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Bioaccumulation of heavy metals in earthworms from field contaminated soil in a subtropical area of China

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Abstract

Bioaccumulation factors for heavy metals (Cd, Zn, Cu, and Pb) were examined for selected earthworm species (Metaphire californica, Amynthas homochaetus, Amynthas pecteniferus, and Amynthas heterochaetus) that inhabit metal-polluted soils in a subtropical area (Hunan Province) of South China. The earthworms had high plasticity in inhabiting in situ contaminated areas and showed high uptake of the heavy metals and capability for their accumulation in the tissues. The bioaccumulation factor (BAF) were greatest for cadmium and ranked as follows: Cd (10.6–18.8) >> Zn (1.15–1.75) > Cu (1.01–1.35) > Pb (0.56–0.95). Earthworm species with the similar BAF of heavy metals (p > 0.05) belong to the same ecological group. Within individual groups, Cd, Cu, Zn, Cu, and Pb concentrations in earthworms are consistently predicted by total and extractable fraction (DTPA-extractable) in soil. Our results provide insights into the ecological relationships and variations in the uptake and accumulation of heavy metals in different earthworm species in contaminated soils in China.

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... Earthworms have been shown to accumulate relatively high levels of metals from soils contaminated by various anthropogenic sources (Beyer et al., 1982;Martin, 2012;Wang et al., 2018). Earthworms ingest organic and mineral material, but their principal food is the microbial biomass associated with these soil materials (McInerney & Bolger, 2000). ...
... A-horizon Pb BSAF values exhibited no significant variation with distance from the road. The comparatively low Pb levels in earthworms compared to A-horizon soil may be attributed to sorption and chelation reactions that restrict Pb mobility and bioavailability in the A-horizon (Bolan et al., 2014;Rodríguez-Seijo et al., 2017;Wang et al., 2018) or to epigeic feeding patterns. On mine-tailing contaminated pasture soil, Dai et al. (2004) reported that Pb BSAF was < 1 for two species of earthworms (0.08-0.38 in Aporrectodea caliginosa and 0.04-0.13 in Lumbricus rubellus). ...
... Table 1 shows that earthworms in both NACE and ROCR were two to four times as concentrated in Zn as the O-horizon and A-horizon soil where they were collected. Previous research reported that earthworms have higher Zn concentrations than the O-horizon and mineral soil (Gish & Christensen, 1973;Morgan & Morgan, 1988;Richardson et al., 2015a;Wang et al., 2018). Nannoni et al. (2014) explained that Zn is essential for earthworm growth, maturation, and reproduction, and may be required for metabolic activities. ...
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Heavy metals emitted by vehicles have the potential to accumulate in soil near roadways, threatening the health of soil, plants, animals, and humans. This study evaluates Pb, Zn, and Cu levels in forest O‐horizons, mineral soil, and earthworms near busy roadways in the metro‐Washington, DC area. The study sites comprised road‐edge environments within urban parks. Six transects were sampled in each park, collecting mineral soil at 1‐ to 30‐m distances from the road edge and dividing it into eight depth increments (0–30 cm). O‐horizon plant litter and earthworm samples were also collected at these locations. All samples underwent total Pb, Zn, and Cu X‐ray fluorescence analysis. Generally, Pb concentrations (in upper 0–10 cm) were 1–4.8 times higher at 3 m compared to 30 m from the road, with less consistent gradients for Zn and Cu. Concentrations peaked near the soil surface, with lower levels in the O‐horizon above and deeper soil layers. Leaded vehicle fuel was phased out by the early 1980s, but legacy Pb contamination persisted in roadside forests, averaging 365 mg kg⁻¹ in the upper 10 cm within 3 m of the roadway (< EPA action level of 1200 mg kg⁻¹ for non‐play areas). Zinc, often present in vehicle tires, accumulated in earthworms to 192–592 mg kg⁻¹, concentrations exceeding those in the soil, while Pb and Cu were less concentrated in earthworms than in either O‐horizon or mineral soil. Factors such as plant uptake, erosion, wind, soil texture, and metal solubility influence how heavy metals redistribute and bioaccumulate in the O‐horizon, mineral soil, and soil fauna.
... Gut cleared earthworms were then placed in beakers and dried in a TK/L 4105 (EHRET) at 60 °C for 48 hours and weighed. Dry earthworms were then digested following the method by Wang et al. (2018). Samples were then diluted, centrifuged and subjected to flame atomic absorption spectrophotometer (FAAS) analysis in High Tech Laboratory, University of agriculture Faisalabad following the method of (Zhang and Reynolds, 2019). ...
... But, Cd accumulation in earthworm (Eudrilus eugeniae) tissues was more than that of Pb which was opposite to present study (Pattnaik and Reddy, 2011). This change in bio-assimilation and uptake of heavy metals by earthworm tissues could be due to exposure rout or particle size of amendments, dietary habits (Vijver et al., 2005) and behavioral adaptations (Pattnaik and Reddy, 2011;Wang et al., 2018). Furthermore, ingestion of any organic matter containing metals is big source of metal uptake by earthworms (Nannoni et al., 2014). ...
... As the concentrations of CD increased, in soil-CD treatments, the BAFs values were decreased in all treatments (except T 1 ) due to formation of organometallic complexes (CD as organic source) which reduce the uptake of heavy metals (Singh and Kalamdhad, 2013). However, the BAFs values examined in this work were decreased compared to previous workers (Wang et al., 2018). This BAFs values difference might be due to varies concentrations of the metals (Hobbelen et al., 2006), exposure period (Pattnaik and Reddy, 2011), habitat variations, food preferences (Quenea et al., 2009), metabolic physiology and earthworm species specificity (Wu et al., 2020). ...
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To investigate the role of cow dung in soil reclamation and bio assimilation along with bio accumulation of heavy metals in earthworm (P. posthuma) (N=900) earthworms were used and treatment groups of CD-soil mixture of different proportion of cow dung were designed. Nonlethal doses of lead acetate and cadmium chloride were added in treatment groups. Mature P. posthuma were released in each experimental pot maintaining the favorable conditions. The pH, carbon, nitrogen, phosphorus, exchangeable cations, and heavy metal level of each mixture was evaluated. The results indicated that bio-assimilation of Pb and Cd by P. posthuma were significantly (P ˂ 0.01) higher in different soil-CD treatments compared to control. Highest bio-assimilation of both metals was observed in T 1 of both groups (Pb = 563.8 mg/kg and Cd = 42.95 mg/kg). The contents of both metals were significantly (P ˂ 0.05) lowered in casting. The nutrient concentration in the final castings of all soil-CD treatments were also equally transformed from less or insoluble to more soluble and available for plants, except for carbon level which increased with CD proportion. It is concluded that cow dung as organic matter has a positive effect on soil reclamation and bio-assimilation of metals by P. posthuma. RESUMO Para investigar o papel do esterco de vaca na recuperação do solo e bioassimilação, juntamente com a bioacumulação de metais pesados em minhocas (P. posthuma) (N = 900), minhocas foram usadas e grupos de tratamento de mistura CD-solo de diferentes proporções de esterco de vaca foram projetados. Doses não letais de acetato de chumbo e cloreto de cádmio foram adicionadas aos grupos de tratamento. P. posthuma maduros foram liberados em cada vaso experimental, mantendo as condições favoráveis. Foram avaliados o pH, carbono, nitrogênio, fósforo, cátions trocáveis e nível de metais pesados de cada mistura. Os resultados indicaram que a bioassimilação de Pb e Cd por P. posthuma foi significativamente (P ˂ 0,01) maior em diferentes tratamentos de solo-CD em relação ao controle. A maior bioassimilação de ambos os metais foi observada em T1 de ambos os grupos (Pb = 563,8 mg / kg e Cd = 42,95 mg / kg). O conteúdo de ambos os metais foi significativamente (P ˂ 0,05) reduzido na fundição. A concentração de nutrientes nas fundições finais de todos os tratamentos de solo-CD também foi igualmente transformada de menos ou insolúvel para mais solúvel e disponível para as plantas, exceto o nível de carbono que aumenta com a proporção de CD. Conclui-se que o esterco de vaca como matéria orgânica tem um efeito positivo na recuperação do solo e na bioassimilação de metais por P. posthuma. Palavras-chave: esterco de vaca, bioassimilação, metais pesados, recuperação de solo, Pheretima posthuma.
... Gut cleared earthworms were then placed in beakers and dried in a TK/L 4105 (EHRET) at 60 °C for 48 hours and weighed. Dry earthworms were then digested following the method by Wang et al. (2018). Samples were then diluted, centrifuged and subjected to flame atomic absorption spectrophotometer (FAAS) analysis in High Tech Laboratory, University of agriculture Faisalabad following the method of (Zhang and Reynolds, 2019). ...
... But, Cd accumulation in earthworm (Eudrilus eugeniae) tissues was more than that of Pb which was opposite to present study (Pattnaik and Reddy, 2011). This change in bio-assimilation and uptake of heavy metals by earthworm tissues could be due to exposure rout or particle size of amendments, dietary habits (Vijver et al., 2005) and behavioral adaptations (Pattnaik and Reddy, 2011;Wang et al., 2018). Furthermore, ingestion of any organic matter containing metals is big source of metal uptake by earthworms (Nannoni et al., 2014). ...
... As the concentrations of CD increased, in soil-CD treatments, the BAFs values were decreased in all treatments (except T 1 ) due to formation of organometallic complexes (CD as organic source) which reduce the uptake of heavy metals (Singh and Kalamdhad, 2013). However, the BAFs values examined in this work were decreased compared to previous workers (Wang et al., 2018). This BAFs values difference might be due to varies concentrations of the metals (Hobbelen et al., 2006), exposure period (Pattnaik and Reddy, 2011), habitat variations, food preferences (Quenea et al., 2009), metabolic physiology and earthworm species specificity (Wu et al., 2020). ...
Article
Full-text available
To investigate the role of cow dung in soil reclamation and bio assimilation along with bio accumulation of heavy metals in earthworm (P. posthuma) (N=900) earthworms were used and treatment groups of CD-soil mixture of different proportion of cow dung were designed. Nonlethal doses of lead acetate and cadmium chloride were added in treatment groups. Mature P. posthuma were released in each experimental pot maintaining the favorable conditions. The pH, carbon, nitrogen, phosphorus, exchangeable cations, and heavy metal level of each mixture was evaluated. The results indicated that bio-assimilation of Pb and Cd by P. posthuma were significantly (P ˂ 0.01) higher in different soil-CD treatments compared to control. Highest bio-assimilation of both metals was observed in T 1 of both groups (Pb = 563.8 mg/kg and Cd = 42.95 mg/kg). The contents of both metals were significantly (P ˂ 0.05) lowered in casting. The nutrient concentration in the final castings of all soil-CD treatments were also equally transformed from less or insoluble to more soluble and available for plants, except for carbon level which increased with CD proportion. It is concluded that cow dung as organic matter has a positive effect on soil reclamation and bio-assimilation of metals by P. posthuma. RESUMO Para investigar o papel do esterco de vaca na recuperação do solo e bioassimilação, juntamente com a bioacumulação de metais pesados em minhocas (P. posthuma) (N = 900), minhocas foram usadas e grupos de tratamento de mistura CD-solo de diferentes proporções de esterco de vaca foram projetados. Doses não letais de acetato de chumbo e cloreto de cádmio foram adicionadas aos grupos de tratamento. P. posthuma maduros foram liberados em cada vaso experimental, mantendo as condições favoráveis. Foram avaliados o pH, carbono, nitrogênio, fósforo, cátions trocáveis e nível de metais pesados de cada mistura. Os resultados indicaram que a bioassimilação de Pb e Cd por P. posthuma foi significativamente (P ˂ 0,01) maior em diferentes tratamentos de solo-CD em relação ao controle. A maior bioassimilação de ambos os metais foi observada em T1 de ambos os grupos (Pb = 563,8 mg / kg e Cd = 42,95 mg / kg). O conteúdo de ambos os metais foi significativamente (P ˂ 0,05) reduzido na fundição. A concentração de nutrientes nas fundições finais de todos os tratamentos de solo-CD também foi igualmente transformada de menos ou insolúvel para mais solúvel e disponível para as plantas, exceto o nível de carbono que aumenta com a proporção de CD. Conclui-se que o esterco de vaca como matéria orgânica tem um efeito positivo na recuperação do solo e na bioassimilação de metais por P. posthuma. Palavras-chave: esterco de vaca, bioassimilação, metais pesados, recuperação de solo, Pheretima posthuma.
... The bioavailability of TE in soils is considered a dynamic process comprising three distinct steps: (1) environmental availability, i.e., the total amount of TE in the soil, including both actual and potential fractions, which can be dissolved from the soil matrix into the pore water; (2) environmental bioavailability, i.e., the amount of dissolved fraction in the pore water that can be taken up by plant roots or other soil organisms; and (3) toxicological bioavailability, i.e., the amount of TE that can physiologically induce bioaccumulation or other effects within plants depending on translocation, metabolism, and degradation [3,[8][9][10]. All these approaches to bioavailability are strongly affected by soil physicochemical properties [3,7,[10][11][12][13]. Soil components imply the sorption processes and control TE behavior because soils differ greatly in their sorption capacity, their cation and anion exchange ability, and the binding energies of their sorption sites. ...
... The development of effective tools to accurately predict the bioavailable fraction of metals constitutes a very important step in providing a risk assessment of the potential exposure of soil-dwelling organisms and can contribute to improvements to ecosystem health, as well as in remediated ecosystems. The methods for the measurement of TE availability are based on different techniques, including chemical extraction [9,10,12,13,21,24,25], modeling processes [26,27], and bioassays [7,8,12,13,21,24,28,29]. Of these, bioassays give a more direct measurement of biological responses, as well as the real bioaccumulation rate of TE [8,12,13,21,[29][30][31]. ...
... The development of effective tools to accurately predict the bioavailable fraction of metals constitutes a very important step in providing a risk assessment of the potential exposure of soil-dwelling organisms and can contribute to improvements to ecosystem health, as well as in remediated ecosystems. The methods for the measurement of TE availability are based on different techniques, including chemical extraction [9,10,12,13,21,24,25], modeling processes [26,27], and bioassays [7,8,12,13,21,24,28,29]. Of these, bioassays give a more direct measurement of biological responses, as well as the real bioaccumulation rate of TE [8,12,13,21,[29][30][31]. ...
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The aim of this study was to assess the impact of soil amendments, characterized by different sorption properties, on the effectiveness of trace elements’ (Cu, Zn, Pb, Cd, Ni, and Cr) stabilization and bioavailability to earthworms. The study was conducted as a microcosm experiment using soil derived from a heavily contaminated post-industrial area. The Eisenia veneta earthworm was cultured for 4 weeks in soils amended with materials characterized by different properties, origins, and potential effects on limiting the availability of metals in soils: two type of compost (Zabrze compost-ZC; GWDA compost-GC), two types of biosolid (Bełchatów biosolids-BB, Grabów biosolids-GB), calcium phosphate (CP), iron oxide (IO), bentonite (BE), rock waste (RW), and limestone (CC). After the incubation, the biomass and survival numbers of the earthworm species decreased significantly (p < 0.05). The accumulation of metals in the earthworm tissues expressed by the bioaccumulation factor value (BSAF) were dependent on the type of amendment applied to the soil. The highest decrease in the earthworms’ weight and survival rate was caused by compost (72%) and bentonite (33%), while the lowest was caused by the rock waste (10%) and iron oxide (11%). The biosolids exhibited the greatest toxicity, causing the mortality of all the earthworms. The accumulation of metals in earthworm tissues and the BSAF value were dependent on the type of amendment applied to the soil. The BSAF for the contaminated soil by Cd decreased to the greatest extent after the addition of ZC (by 57%), GC (55%), CP (41%), and IO (37%). A similarly positive effect was noted for Pb after IO addition (45% decrease). The Zn, Cr, and Ni concentration in earthworms, contrary to other elements, increased, regardless of the amendment. The results showed that the applied soil amendments were characterized by varying potential for the reduction in the metal bioavailability in the soil, depending on their composition and physicochemical properties. Moreover, earthworms may exhibit a diversified response to soil amendments as a result of the impact of amendment on the metal forms in soils and their direct impact on organisms. Generally, the Cd was easily transferred from the soil into and accumulated in the earthworm tissues. Our study confirms that this element creates the highest risk for the trophic chain in soils affected by the Zn and Pb smelting industry. Moreover, greater Zn supply reduces the accumulation of Cd in animal bodies. This study provides valuable practical knowledge on the short-term biological effects of a range of soil amendments in metal-contaminated soils.
... Additionally, bioaccumulation factor (BAF) was calculated according to the methodology utilized by Wang et al. (2018), to determine the accumulation potential in earthworm tissue of every metal in the exposure bioassay. ...
... A study conducted on earthworms collected from different sampling sites in a contaminated field in China, found higher bioaccumulation factors in the following order: Cd (10.6 -18.8) > Zn (1.15 -1.75) > Cu (1.01 -1.35) > Pb (0.56 -0.95). The authors of this study indicated that the bioaccumulation of these elements in earthworms is influenced by different factors related to the habits of the organism and the depth at which they are found, allowing them to absorb elements through skin contact, or through the ingestion of contaminated organic matter, and absorbing the metals through intestinal tissues (Wang et al. 2018). ...
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Purpose The aim of this study was to evaluate the toxic potential of mining residues by 1) evaluating the concentrations of heavy metals and arsenic in soil and earthworm’s samples from impacted and reference sites in Charcas and Villa de la Paz, San Luis Potosí, México; and 2) evaluating effects by laboratory bioassays and the comet assay in the earthworm Eisenia andrei. Methods The quantification of metals in soils was carried out by the Thermo Scientific Niton XL3t Gold Serie 500 environmental analyzer for X-ray fluorescence (XRF), and in the earthworm tissue through ICP-MS. The evaluation of the genotoxic potential of soils was assessed through movility and exposure bioassays with earthworms, determining DNA damage using the comet assay at the end of the bioassays. Results In Charcas, the concentrations in soils of heavy metals from highest to lowest were: Pb > Cu > Mn > Cd (Impacted); and Mn > Pb (Reference). In Villa de la Paz, the concentrations were: As > Mn > Cu > Pb (Impacted) and Mn > Pb > As (Reference). The exposure pattern to heavy metals in earthworms in Charcas was: Pb > As (Impacted and Reference); and in Villa de la Paz it was: As > Mn > Pb > Cu > Cd (Impacted), y Pb > As (Reference). In both mining districts, the magnitude of DNA damage in earthworms was: Impacted > Reference > Control. Conclusion The results indicate that the impacted soils of both sites represent a significant source of exposure to edaphic organisms, with a notable genotoxic potential.
... A similar picture was seen in Pb and Zn and shows the enormous capability of the earthworm to bioaccumulate metals. Earthworms are known to bioaccumulate heavy metals from soils (Wang et al. 2018;Wijayawardena et al. 2018;Parihar et al. 2019;Huang et al. 2021;Xiao et al. 2022). As the metal concentrations increased in the earthworms over time it decreased from the soil (Fig. 1b). ...
... A significant positive linear relationship was found between the concentrations of each metal in the earthworms at days 35 and 56 (Fig. 1c) as well as relative to the soil both after 35 and 56 days (Fig. 2). This is in agreement with the findings of several authors who have shown that metal uptake by earthworms could be consistently predicted from the levels in the soil (Haghparast et al. 2013;Wang et al. 2018;Huang et al. 2021;Lobo et al. 2021). Cu was less correlated, probably due to the earthworm's ability to regulate it internally since it is an essential metal (Giska et al. 2014;Richardson et al. 2020). ...
Article
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Elevated heavy metal concentrations in soils are a cause for concern as they are hazardous to soil organisms including earthworms which are considered as ecosystem engineers. Current ecotoxicity tests predominantly use temperate earthworm species, and thus there is the need to include a broader genera of native species to improve ecological risk assessment. Alma nilotica, is a tropical anecic earthworm species that survives well under laboratory conditions and has potential for use in ecotoxicology testing but lacks published toxicity data for important pollutants. Growth and reproduction bioassays were carried out with A. nilotica to determine the relationship between the concentrations of Cu, Zn, Pb and Cr in spiked soils and their bioaccumulation and toxic effects. Positive linear relationships were found between soil-metal and internal earthworm-metal concentrations. Cu did not inhibit growth up to 35 days of exposure but became toxic with longer exposure duration. Zn was not regulated by A. nilotica although it is an essential metal that is well regulated by Eisenia sp. commonly used in standard ecotoxicity tests, showing differences in metal regulation by earthworms of different ecological categories. Based on bioaccumulation factors (BAFs), growth inhibition and reproduction effects the metals were ranked in decreasing toxicity as Pb > Cr > Zn > Cu. The mean 20% Internal Effects Concentrations (IEC20s) for reproduction were 1.04, 2.9, 8.3 and 224.2 mg metal kg−1 earthworm for Pb, Cr, Zn and Cu respectively. These data can contribute to the improvement of metal risk assessment particularly in tropical contexts.
... Pandey et al. (2016) in their experiments found that after 28 days of exposure, Cd and Pb concentrations in earthworms (Metaphire posthuma) were considerably greater than those in the control group. Several studies have reported heavy metal bioaccumulation in earthworms (Chao et al., 2016;Cao et al., 2017;Tang et al., 2017;Wang et al., 2018b;Zhao et al., 2018;Maity et al., 2018;Ecimovic et al., 2018;Yuvaraj et al., 2020;Zaltauskaite et al., 2020). After bioaccumulation, heavy metals exert various toxic effects on earthworms. ...
... The bioavailability and dispersion of heavy metals in the soil have been found to be influenced by earthworms. Wang et al. (2018b) in their studies found that earthworms lowered the proportion of As in the residual fraction and increased the proportion of As linked to Fe oxides. As a result, bound arsenic's bioavailability may be increased. ...
Article
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Earthworms are important soil organisms, contributing to many beneficial ecological services that can be harmed by heavy metal contamination. Because of their permeable skin and constant contact with soil through their digestive tract, they are extremely sensitive to soil contamination. Heavy metals get bioaccumulated in their bodies and cause major health problems. In this review, we describe the findings of various studies on the toxicity of heavy metals to earthworms, mechanisms of toxicity, detoxification responses and consequences on the environment. Heavy metals have deleterious impact on earthworms at all levels of organization, including inhibiting enzyme activities, causing DNA damage, reducing survival, growth and cocoon production, altering behavior and reducing total earthworm community diversity and biomass. These negative effects of heavy metals on earthworms can have disproportionate adverse consequences for community stability as well as serious ecological consequences for the entire terrestrial ecosystem. So, heavy metal pollution of soil poses a serious threat to earthworms, reducing their activity and posing a risk to the environment and human health.
... The order of average enrichment coefficients for six heavy metals is Cd > Cu > Zn > Ni > Pb > Cr. Among them, the enrichment coefficients of Cu and Zn are close, which is consistent with most reported results [25,26], because both Cu and Zn are biologically necessary elements; The difference between the bioconcentration coefficients of Cr, Ni and Pb is also small, and these three elements are significantly lower than Cd, Cu and Zn, which is mainly due to the low bioavailability of these three elements in the soil. At the same time, the average BCF of earthworms to Cd is 4.00, while the average BCF of other elements is less than 1, which is due to the strong mobility of Cd in soil, which is easy to be absorbed and enriched by earthworms [27,28]. ...
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p>This summary outlines a significant challenge in ecological risk assessment of contaminated sites: quantitatively evaluating the ecological effects of combined heavy metal pollution in real-world soil. The study proposes a novel quantitative ecological assessment approach that integrates both broad ("top-down") and detailed ("bottom-up") knowledge. This approach involves three key steps: identifying effective biomarkers, pinpointing dominant pollutants, and assessing the combined effects of various exposure types and contaminants. To validate this approach, researchers examined an abandoned electronic waste site in Jiangsu Province using soil microcosms with earthworms. By analyzing biomarkers such as malondialdehyde (MDA), metallothionein (MT), catalase (CAT), superoxide dismutase (SOD), and reduced glutathione (GSH), they found that earthworms accumulated heavy metals in the order of Cd > Cu > Zn > Ni > Pb > Cr. Principal component analysis (PCA) identified GSH, CAT, and MDA as effective biomarkers, with Cd and Zn as the primary contaminants. The study revealed significant linear relationships between biomarker changes and specific heavy metal concentrations in soil (e.g., GSH with total Cd and DTPA-extractable Zn, MDA with DTPA-extractable Cd, and CAT with total Zn and bioaccumulated Zn). The sensitivity of the biomarkers to heavy metal contamination was ranked as GSH > CAT > MDA. Furthermore, the study highlighted complex interactions among different heavy metals, exposure types (e.g., soil vs. bioaccumulated), and biomarkers, emphasizing the need for comprehensive assessments in contaminated site evaluations.</p
... Vol:. (1234567890) ways including absorption through dermal contact and adsorption through the intestinal tissues (Nirola et al., 2016;Wang et al., 2018b). Regression analysis displayed that A. caliginosa had a quite constant body concentration of Cu, Cd, and Pb and a slight increase in Zn concentration with the increase in the soil heavy metal concentration. ...
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The presence of elevated levels of heavy metals in soil poses a significant environmental concern with implications for human health and other organisms. The main objective of our study was to reduce the gap information of seasonal abundance, distribution of heavy metals in soil, leaf litter, and some macroinvertebrates in a citrus orchard (Citrus sinensis) in Sohag Governorate, Egypt. The heavy metals copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) were determined by atomic absorption spectrometry. Degree of contamination (DC) was determined for both soil and leaf litter contamination. However, the bioaccumulation factor (BAF) was estimated to determine metal accumulation in the macroinvertebrates including earwigs Anisolabis maritima, chilopoda Scolopendra moristans, spider Dysdera crocata, and earthworm Aporrectodea caliginosa. The study area had clay-loam with varying organic matter, salinity, and pH levels. The degree of contamination varied among seasons, with the highest levels typically observed in autumn in both soil and leaf litter. The soil ranged from low contamination (1.82) to high contamination levels (4.4), while the leaf litter showed extremely high (30.03) to ultra-high (85.92) contamination levels. The mean ecological risk index results indicated that the sampling area had moderate ecological risk levels for Cd (44.3), Zn (42.17), and Pb (80.05), and extremely high levels for Cu (342.5). Heavy metal concentrations in the selected fauna were the highest in autumn, and the bioaccumulation factor varied among species and seasons with some species classified as e-concentrators, micro-concentrators, and macro-concentrators of certain heavy metals. Scolopendra moristans exhibited the highest mean metal concentrations (Cd, Pb, and Zn), while Aporrectodea caliginosa had the lowest. Thus, the differences in heavy metal concentrations found in different soil taxa highlight the significance of taxing a holistic understanding of feeding mechanisms into account when evaluating the potential risk for animals that consume invertebrates.
... In arid ecosystems, intensified anthropogenic activities could easily lead to ecological degradation as the area is rather fragile, and restoration would be difficult if it was contaminated [14]. Industrial activities such as mining and smelting in arid regions often release into the environment, which in most cases brings the serious pollution of PTEs [15]. ...
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Intensive mining activities in large-scale opencast coal mines have had a significant impact on the local environment. Elements that are potentially harmful to the environment are brought to the surface from deep underground, altering the geochemical conditions for their transport and redistributing them to the surface, causing serious local pollution. However, in-depth studies of toxic metal contamination in soils of arid coal mining areas have not yet received the attention they deserve. Although previous studies have conducted a great deal of research on heavy metal elements in surface coal mine soils, there are few studies related to the more seriously polluted surface coal mines in the arid regions of Northwest China, and there are no in-depth studies on the ecology of soil heavy metal contamination, health risks and source analysis according to the authors’ knowledge. To make up for this shortcoming, the present study takes Zn, Cu, Cr, Pb, Hg, and As in the surroundings of the tertiary coal mines in the Hongsachuan Mining Area (northern Xinjiang, China) as an example. The health, ecological risks, and pollution sources of heavy metal elements in surface coal mine soils were comprehensively analyzed. The results showed that the average concentrations of Cr, Hg, and As in the soils of open-pit coal mines greatly exceeded the corresponding provincial background values, with the Cr content exceeding China’s soil environmental quality standard Ⅰ and the As content even higher than standard Ⅱ (GB15618-1995). Geostatistical and multivariate statistical results showed that the six metals analyzed in this study can be divided into four groups, as follows. Group 1 included Zn and Cu and was mainly controlled by natural sources related to soil parent materials. Group 2 consisted of Cr and Hg and was associated with industrial practices. Group 3 was explained by As and was mainly from coal combustion during the mining activities. Group 4 was Pb and was dominantly from natural sources, together with vehicular emission during the mining activities, indicating a mixed source. Potential ecological risk index (PER) values exhibited low ecological risk in contaminated soils with Zn, Cu, Pb, and Cr, and only 10% of As samples exhibited moderate risks, while 77% of Hg samples posed ecological risks at different level, implying that Hg was the main contributor for comprehensive risk index (RI). Regardless of non-carcinogenic and carcinogenic health risk assessment, As was the primary risk element followed by Cr, and children tended to have a higher health risk than adults. In this paper, statistical methods, pollution assessment methods, and potential ecological risk models are skillfully combined, and relevant conclusions are drawn based on the human and economic geographical background information of the study area. The results can provide references for the investigation and evaluation of soil heavy metals and quantitative analysis of pollution sources in the same type of areas. In order to grasp the pollution level of potential toxic elements in the soil of large open-pit coal mines in arid areas, effective source-cutting measures are taken to provide data support the sustainable management of coal mines and local soil safety utilization measures.
... This pattern shows that E. fetida decreased the content of Cd in the soil because earthworms play an important role in enriching heavy metals, thereby protecting soil health. This finding is consistent with previous research (Wang et al., 2018b). The specific effect of heavy metal adsorption and desorption on MPs is related to the type and size of MP (Sheng et al., 2021). ...
Article
LDPE had no effect on the mortality, growth, and reproduction of earthworms. LDPE did not alter the mortality, growth, and reproduction of earthworm caused by Cd. LDPE alleviated histopathological damage to earthworms caused by Cd. LDPE alleviated DNA damage in earthworm coelomocytes caused by Cd. LDPE did not affect the accumulation of Cd in earthworms. Cadmium (Cd) can accumulate in the food chain, with serious impacts on human health and safety. Microplastics (MPs) such as low-density polyethylene (LDPE) should be considered not only as a single pollutant but also as a carrier of other pollutants. In this study, we investigated the joint effects of 30% LDPE and 313 mg kg−1 Cd on mortality, growth, reproduction, microstructure, DNA damage, oxidative stress, and mRNA levels in the earthworm Eisenia fetida. We found that 313 mg kg−1 Cd inhibited growth and reproduction and damaged the microstructures of the skin and intestine. Meanwhile, LDPE had no effect on the mortality, growth, or cocoon production of earthworms. Moreover, it did not increase the mortality, growth, or inhibition of cocoon production caused by Cd and instead alleviated the DNA damage in coelomocytes caused by Cd treatment. Finally, it did not alter the accumulation of Cd in the worms. These indicators can be used for toxicity safety assessment and soil ecological risk assessment of LDPE and Cd cooccurrence in soil.
... Van Hook et al. found that earthworms fed chromium-polluted soil had an enrichment effect, and the chromium content in their bodies was 17 times that of the soil [21]. However, studies have shown that different ecological types of earthworms have different abilities to accumulate heavy metals in their bodies [22]. ...
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Soil heavy metal pollution has become one of the major environmental issues of global concern and solving this problem is a major scientific and technological need for today’s socio-economic development. Environmentally friendly bioremediation methods are currently the most commonly used for soil heavy metal pollution remediation. Via controlled experiments, the removal characteristics of chromium from contaminated soil were studied using earthworms (Eisenia fetida and Pheretima guillelmi) and plants (ryegrass and maize) at different chromium concentrations (15 mg/kg and 50 mg/kg) in acidic and alkaline soils. The effects of chromium contamination on biomass, chromium bioaccumulation, and earthworm gut microbial communities were also analyzed. The results showed that E. fetida had a relatively stronger ability to remove chromium from acidic and alkaline soil than P. guillelmi, and ryegrass had a significantly better ability to remove chromium from acidic and alkaline soil than maize. The combined use of E. fetida and ryegrass showed the best effect of removing chromium from contaminated soils, wih the highest removal rate (63.23%) in acidic soil at low Cr concentrations. After soil ingestion by earthworms, the content of stable chromium (residual and oxidizable forms) in the soil decreased significantly, while the content of active chromium (acid-extractable and reducible forms) increased significantly, thus promoting the enrichment of chromium in plants. The diversity in gut bacterial communities in earthworms decreased significantly following the ingestion of chromium-polluted soil, and their composition differences were significantly correlated with soil acidity and alkalinity. Bacillales, Chryseobacterium, and Citrobacter may have strong abilities to resist chromium and enhance chromium activity in acidic and alkaline soils. There was also a significant correlation between changes in enzyme activity in earthworms and their gut bacterial communities. The bacterial communities, including Pseudomonas and Verminephrobacter, were closely related to the bioavailability of chromium in soil and the degree of chromium stress in earthworms. This study provides insights into the differences in bioremediation for chromium-contaminated soils with different properties and its biological responses.
... Lumbricus rubellus was used for 90 days to rehabilitate disturbed soil in Malaysia that was contaminated by toxic elements (Cu, Mn, Pb, Fe, Cr, Ni, Zn, and As) (Cheng-Kim et al., 2016). According to Wang et al. (2018), Cd, Cu, Pb, and Zn contamination was found in areas (soil systems) close to mining sites. Earthworm species of the Amynthas heterochaetus, Metaphire californica, Amynthas pecteniferus, and Amynthas homochaetus, as well as others, were common in these areas. ...
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Heavy metals are a severe concern that causes a variety of health issues in both human beings and animals. They also have an impact on the variety of soil organisms and the ecosystem. The inoculation of earthworms in their natural environments can assist in monitoring heavy metal concentrations. The earthworm Lampito mauritii is a significant species for bioaccumulating highly toxic metals from soil and organic wastes for vermicomposting. This research aims to investigate the concentrations of heavy metals such as cobalt (Co), chromium (Cr), and lead (Pb) found in various animal dungs, earthworm Lampito mauritii body tissues before and after vermicomposting, soil, and rice grains (Oryza sativa L.). Compared to the initial feed mixture of various animal dungs, it was found that the Co, Cr, and Pb heavy metal concentrations decreased (P < 0.05) in the final vermicompost. When the soil was mixed with cow dung vermicompost that had been inoculated with the earthworm Lampito mauritii, the highest concentrations of cobalt (Co) and chromium (Cr) were found to decrease by nearly 44.03% and 17.08%, respectively, while the maximum concentration of lead (Pb) was significantly reduced by 32.46% when the soil was mixed with goat dung. Heavy metal concentrations in rice grains were measured both before and after harvesting. When the soil was combined with goat dung vermicompost, the highest concentrations of Co, Cr, and Pb were found to decrease. Before and after crop harvesting, heavy metal concentrations were also investigated in the earthworm body in soil and soil with vermicompost of different animal dungs. When soil and cow dung were combined, the highest amount of cobalt (Co) was found to increase by 29.91% in the earthworm Lampito mauritii body, whereas the highest concentrations of chromium (Cr) and lead (Pb) were found to increase by 18.05% and 30.22%, respectively, in the earthworm body when soil and buffalo dung were combined. For the protection of both the health of humans and the environment, vermicomposting and the utilization of Lampito mauritii are considered to be efficient methods for extracting these harmful metals from rice field soil.
... However, it is dependent by the concentration of available/total metals in soils (Beaumelle et al., 2015). Also, it may depend on the earthworm species because of their different burrowing activities, ingestion behavior and niche structure (Suthar et al., 2008;Wang et al., 2018;Xiao et al., 2020). However, the gathering pattern is liable to the element because they present different chemical properties as well as mobility and bioavailability (Wang et al., 2014;Fan et al., 2016;Boughattas et al., 2018;Aziz et al., 2019). ...
Article
Heavy metal pollution is causing harmful consequences on soil fertility, and earthworms are frequently employed as test organisms to evaluate the ecotoxicity of polluted soils. In this study, Eisenia andrei was exposed for 7 and 14 days to polymetallic contaminated soils collected from an industrial zone in the south-eastern Tunisia. Earthworm growth, heavy metal accumulation, genotoxicity, cytotoxicity, biochemical and transcriptional responses were determined. Results revealed a higher accumulation of heavy metals in earthworms after 14 than 7 days of soil exposure, a reduction in lysosomal membrane stability (LMS), besides an increase in micronuclei frequency (MN). Moreover, earthworm oxidative status was affected in terms of increases in malondialdehyde (MDA) and metallothionein (MTs) content, and enhancement of catalase (CAT) and glutathione-S-transferase (GST) activities. An inhibition of acetylcholinesterase (AChE) activity was also observed in treated earthworms, whereas transcriptional data demonstrated an up-regulation of cat, gst, mt, p21 and topoisomerase genes. Overall, these findings support the use of earthworms as suitable bioindicator species for pollution monitoring and assessment, advance our understanding of the interaction between heavy metals and earthworms, and provide valuable information about the harmful impact of biota exposure to naturally contaminated soils.
... Our findings were within these ranges except for Cd, which was higher and Se, which was lower in our study. In the study by Wang et al. (2018), transfer of heavy metals into earthworms was lower than in our study for Cd and Zn, whereas higher transfer of Cu and Pb was observed. A study in Kosovo (Latifi et al. 2020) showed lower CR values in earthworms from five different sites for Cd and Zn but higher CRs for Fe than those observed in our study. ...
Article
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Data on the transfer of elements (such as heavy metals) and their radionuclides into organisms is needed for assessing environmental risks. The current data on many elements, species and environments is limited, but more information can be obtained both from field studies and experimental laboratory studies. However, it is essential to evaluate whether experimental studies adequately predict transfer in natural conditions. Moreover, because of the sparsity of species-specific empirical data, it is a common practice in current radioecological modelling to use data available for related species under the assumption that transfer into organisms is similar within broader taxonomic groups. Earthworms and ground beetles are examples of important invertebrates living near soil surface in terrestrial ecosystems. In this study, the transfer of 34 elements from soil to these organisms was studied in a field study conducted in boreal forest. The earthworm concentrations were compared to the values obtained in an experimental mesocosm study using soil from the field site and were found to be highly correlated. This indicates that the results of mesocosm studies can be used for predicting the transfer of elements from soil to fauna in natural conditions. Furthermore, concentrations in individual earthworm and beetle species were found to be similar to those observed in broader groups of related species, indicating that the generic approach used in current radioecological models may be useful for predicting uptake of elements into single species.
... M. californica, A. hupeiensis, A. asacceus accumulated Zn (2.86-6.46 m mol kg − 1 ), Cu (0.55-1.62 m mol-kg − 1 ), and Cd (0.27-0.60 m mol kg − 1 ), respectively [61]. Through the development of MTs and/or other induced-proteins in their stomach, earthworms can detoxify by reducing the bioavailability of HMs [62,63]. ...
Article
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In recent years, soil pollution by massive accumulation of heavy metals (HMs), microplastics, and refractory hydrocarbon chemicals has become an emerging and global concern, drawing worldwide attention. These pollutants influence soil diversity by hindering the reproduction, abundance, thereby affecting aboveground productivity. The scientific community has recently emphasized the contribution of earthworms to heavy metal accumulation, microplastic degradation, and the decomposition of organic matter in the soil, which helps maintain the soil structure. This review paper aimed to compile scientific facts on how earthworms cope with the effect of HMs, microplastics, and plant polyphenols so that vermiremediation could be widely applied for well-being of the soil ecosystem by environmentalists. Earthworms have special surface-active metabolites in their guts called drilodefensins that help them defend themselves against the oxidative action of plant polyphenols. They also combat the effects of toxic microplastics, and other oxidative compounds by elevating the antioxidant activities of their enzymes and converting them into harmless compounds or useful nutrients. Moreover, earthworms also act as biofilters, bioindicators, bioaccumulators, and transformers of oxidative polyphenols, microplastics, toxic HMs, and other pollutant hydrocarbons. Microorganisms (fungi and bacteria) in earthworms' gut also assist in the fixation, accumulation, and transformation of these toxicants to prevent their effects. As a potential organism for application in ecotoxicology, it is recommended to propagate earthworms in agricultural fields; isolate, and culture enormously in industry, and inoculate earthworms in the polluted soil, thereby abate toxicity and minimizing the health effect caused by these pollutants as well enhance the productivity of crops.
... Filtered digest liquid was determined by an inductively coupled plasma-mass spectrometry (ICP-MS; 7700ce, Agilent Technologies, USA). The authenticated reference substance (Shrimp powder, GBW10050) was used to ensure the analysis quality, and the overall recovery deviation was less than 5% (Wang et al., 2018b;Yue et al., 2021). ...
Article
Hazardous pollutants released into the real environment mostly own long-lasting cumulative characteristics and have progressively negative impacts on organisms, which are always neglected in laboratory toxicological tests. Here in this study, the different ecotoxicity of Ag nanoparticles (AgNPs) on earthworm Eisenia fetida was compared via various endpoints and transcriptional sequencing between the 28-day progressively repeated (from 60 to 80, final 100 mg/kg) and one-step (directly to 100 mg/kg) exposure. The results showed that earthworms under progressively repeated exposure showed significantly less biomass loss and reproductive inhibition, as well as lower Ag bioaccumulation (15.6 mg/kg) compared with one-step exposure (17.9 mg/kg). The increases in enzyme activities (superoxide enzyme and catalase) and gene expression (metallothionein) also implied higher antioxidant and genetic toxicity in one-step exposed earthworms compared with those from progressively repeated exposure. Furthermore, the transcriptomic analysis identified 582 and 854 differentially expressed genes in the treatments of one-step and repeated exposure respectively compared with the control group. The results of pathway annotation and classification suggested similar enrichments of damage induction but different in toxic stress responses, whereas earthworms from repeated exposure possessed more detoxification-related pathways like translation and multicellular organismal processes. This study innovatively took into account the impacts of processive exposure occurring in the real environment and elucidated distinctions of toxicity and adaptation caused by different exposure patterns, which provided the theoretical basis for real risk identification under the framework and guidance of traditional toxicology, also the implication for the improvement of eco-toxicological risk assessment.
... The chemical characteristics of the soil, such as organic carbon content, pH, oxide forms, carbonates, and some physical properties such as clay content, might influence the concentration of chemical elements [47]. The soil content of the heavy metals Cr, Cu, Ni, Pb, and Zn was analysed, determined, and interpreted [48][49][50][51][52]. ...
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This study aimed to analyse the bioaccumulation of heavy metal ions in plants of spontaneous flora. An urban area was established from which soil samples were taken and analyses were performed on the content of heavy metal ions. The soil samples were collected from Iasi's urban area to determine the heavy metal concentrations, obtain maps of sensitive land, and determine the content of heavy metals in spontaneous flora and transfer these into an aqueous extract. The investigation of heavy metal ion levels in certain plants revealed the following: (i) all plants from the Brassicaceae accumulate heavy metals, and B. juncea has a great ability to accumulate and transfer Cu, Cr(VI), Cd, Ni, Pb, and Zn towards the shoots; (ii) heavy metals (Fe, Cu, Cr, Mn, Zn) were present in variable concentrations, with mint and nettle being notable for their increased level of iron and thyme, and rattle for its zinc levels; (iii) toxic metals (Pb, Cd, Ni) are present in low concentrations in plants as well as in infusions, except for in primula and plantain, which do not have high levels of Pb and Cd. The results showed that values exceeded the maximum recommended values in areas with industrial pollution. Taking into account the potential for the bioaccumulation of heavy metal ions by plants from spontaneous flora and their use as medicinal plants, it is recommended, based on the studies conducted, to harvest and use plants from soils that do not contain heavy metal ions.
... No damage to soil structure, low cost Poor genetic stability of microorganisms [20,21] Animal remediation No destroy the soil structure, improve the soil condition Long cycle time and small application range [22,23] years. Therefore, the application and improvement of biochar in remediation of soil heavy metal pollution were summarized, and the future development direction of biochar was prospected. ...
... All three sampling sites Wanshou (WSC, 112 • 40 ′ 05''; 26 • 44 ′ 49 ′′ ), Daxing (DXC, 112 • 47 ′ 18''; 26 • 54 ′ 21 ′′ ), and Lupu (LPC, 112 • 79 ′ 50''; 27 • 00 ′ 07 ′′ ) ( Fig. 1) were located in the "hometown of nonferrous metals", Hengyang City, Hunan Province, the subtropical areas of southern China. These sites showed different distances away from mining or tailing areas with over 30 years of pollution history, which were all confirmed as long-term observing and sampling points by our field survey studies began in 2018 Wang et al., 2018bWang et al., , 2018c. ...
Article
Reproduction is a significant biological process for organisms responding to environmental stresses, however, little is known about the reproductive strategies of invertebrates under long-term exposure to contaminations. In this study, earthworm Metaphire californica (Kinberg, 1867) from contaminated fields with an increased metal gradient were collected to investigate their reproductive responses. The results showed heavy metals (Cd, Cu, Zn, and Pb) induced histological damage to earthworms’ seminal vesicles, including tissue disorders and cavities, and decreases in mature spermatozoa. Sperm morphology analysis indicated deformity rates were up to13.2% (e.g. head swollen or missing) for worms from the most contaminated site, which coincided with DNA damages. Furthermore, the computer-assisted sperm analysis (CASA) system was employed for the evaluation of sperm kinetic traits. Results suggested earthworms exposed to higher contamination showed a lower sperm viability rate but faster sperm velocity after re-exposure with Cd solution (like the curvilinear velocity and straight-line velocity paraments) compared with those from relatively clean sites. The activities of lactate dehydrogenase and sorbitol dehydrogenase showed the highest 32.5% and 12.5% up-regulation respectively with the increased metal gradient. In conclusion, this study elucidated the earthworm reproductive toxicity, underlying reproductive compensation, metal stress-induced damages, and adaptive responses caused by heavy metal exposure, while also providing the possibility of sperm trait analysis (CASA) for related earthworm toxicological studies.
... Heavy metals including copper, cadmium, lead, and zinc can be accumulated by the earthworms (Wang et al., 2018a). Through two pathways which include absorption following dermal contact and adsorption through the intestinal tissues, metallic accumulation occurs by earthworms (Leveque et al., 2013;Nirola et al., 2016;Wang et al., 2018b). Report suggests the strong binding ability and tolerance of metals by gut microbiota of other animals (Breton et al., 2013;Giri et al., 2018) and thus, they hypothesized the concept of metal tolerance and removal using intestinal microorganisms of earthworms. ...
Article
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In the present time of speedy developments and industrialization, heavy metals are being uncovered in aquatic environment and soil via refining, electroplating, processing, mining, metallurgical activities, dyeing and other several metallic and metal based industrial and synthetic activities. Heavy metals like lead (Pb), mercury (Hg), cadmium (Cd), arsenic (As), Zinc (Zn), Cobalt (Co), Iron (Fe), and many other are considered as seriously noxious and toxic for the aquatic environment, human, and other aquatic lives and have damaging influences. Such heavy metals, which are very tough to be degraded, can be managed by reducing their potential through various processes like removal, precipitation, oxidation–reduction, bio‐sorption, recovery, bioaccumulation, bio‐mineralization etc. Microbes are known as talented bio‐agents for the heavy metals detoxification process and fungi are one of the cherished bio‐sources that show noteworthy aptitude of heavy metal sorption and metal tolerance. Thus, the main objective of the authors was to come with a comprehensive review having methodological insights on the novel and recent results in the field of mycoremediation of heavy metals. This review significantly assesses the potential talent of fungi in heavy metal detoxification and thus, in environmental restoration. Many reported works, methodologies and mechanistic sights have been evaluated to explore the fungal‐assisted heavy metal remediation. Herein, a compact and effectual discussion on the recent mycoremediation studies of organic pollutants like dyes, petroleum, pesticides, insecticides, herbicides, and pharmaceutical wastes have also been presented.
... Compared with foreign energy forest plants, there are several prominent problems in the excellent energy plants that have been screened in China: first, there are not many excellent varieties or clones [13]. There are many tree species such as Quercus japonica, Robinia pseudoacacia, Amorpha japonica, Sand jujube, sea buckthorn, and willow tree selected in northern China, but there are not many varieties with obvious advantages. ...
Article
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Phytoremediation technology is a measure to purify pollutants in soil or water through the absorption, volatilization, root filtration, degradation, and stabilization of plants, and its core is to find plants with large biomass and high enrichment. The wild willow tree found in Tonglushan is a fast-growing Euphorbiaceae plant, which has strong tolerance to the heavy metal copper (Cu) and has the characteristics of developed root system, barren resistance, and high economic value. Taking willow as the research object, this paper studied the composition, copper enrichment sites, morphology, subcellular distribution characteristics and absorption, transportation, and enrichment mechanism of willow root exudates under copper stress through hydroponic and pot experiments. By adding phosphate fertilizers, inducers, and other agronomic control measures, the strengthening technology and mechanism of Cu-contaminated soil phytoremediation were studied. The main research contents and results are as follows: the results of hydroponics and pot experiments show that the willow tree has a certain tolerance to Cu, and Cu mainly accumulates in its roots. Oxalic acid, succinic acid, tartaric acid, citric acid, and malic acid are the main organic acids in willow root exudates. Root exudation activity acidified the rhizosphere soil, increased acid exchangeability, and reducible Cu content, while other forms of Cu content decreased. Root exudates affect the uptake and accumulation of copper by willow trees by altering the bioavailability of copper in soil.
... On the only hand, infected soil influences earthworm feeding and burrowing [45]. is is newly discovered that increasing soil concentrations significantly inhibits earthworm digging activities, with a significantly prolonged avoidance response (from ∼10% to >80%) [46]. Wang et al. [47] indicate a decrease in the density of earthworms in soil from 70 to less than 20 worms m 2, while Cd content material elevated from 0.81 to over 17.8 mg/kg, and touchy worm species (e.g., A. homochaetus and A. hupeiensis) steadily faded withinside the infected soils. It is possible that raising the soil lead content from 480 to 5060 mg/kg would significantly reduce the worm density from 135 to 5 m 2 of worms [48]. ...
Article
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The earthworm is the most beneficial organism for assessing metallic contamination due to the fact that critical high-quality correlations have been determined between earthworm steel concentrations and soil cadmium, copper, lead, zinc, and mercury concentrations. The mercury compounds are very poisonous for most organisms. Here, we investigated the ability of earthworms (Lumbricus terrestris) to HgCl2 (below laboratory conditions). A study of the effect of five different salt concentrations of mercury chloride (HgCl2) 1 ppm, 5 ppm, 10 ppm, 50 ppm, and 100 ppm was studied on worm survival and calculation of the concentration required to destroy half the number of worms (LC50). The results showed that there is an inverse relationship between these salt concentrations and the time required to perish 100% of worms. It was found that the concentration of 100 ppm is the lethal concentration of half the number (LC50) of the earthworm (Lumbricus terrestris). The effects of the salt concentrations used confirmed their effect on the experimental worm weights as well, so the concentration of 50 ppm was the most influential on earthworm weights of the type of Lumbricus terrestris, as it caused a reduction 12% of worm weights with a significant difference, while the concentrations 1 ppm and 100 ppm were the least effective, as they caused the worms to decrease by only (5%), while the remaining two concentrations 5 ppm and 10 ppm caused their effect to decrease by 7% only. Thus, it can be concluded that lower worm weights have nothing to do with the lethal concentrations of the heavy metal salt (HgCl2). The histological study also showed that low concentrations of mercury chloride salt have less effect on earthworms’ skin tissue compared to higher concentrations.
... These results might be related with the higher OM content usually present in northern soils (Decorte et al., 2016;Xu et al., 2019) and also by the high partition coefficient of esfenvalerate (Kom: 145997 L/kg). Both factors together could lead to pesticide binding to soil OM, consequently an increase pesticide uptake by soil ingestion could occur on earthworms (Belfroid, 1994;Chung and Alexander, 1998;Contreras-Ramos et al., 2006, 2008Wang et al., 2018). TER values in pore water (TER pw ) were under TER critical values (suggesting risk) for both acute and chronic exposure. ...
Article
Plant Protection Products (PPP) raise concerns as their application may cause effects on some soil organisms considered non-target species which could be highly sensitive to some pesticides. The European Food and Safety Authority (EFSA), in collaboration with the Joint Research Centre (JRC) of the European Commission, has developed guidance and a software tool, Persistence in Soil Analytical Model (PERSAM), for conducting soil exposure assessments. EFSA PPR Panel has published recommendations for the risk assessment of non-target soil organisms. We have used PERSAM for calculating PPPs predicted environmental concentrations (PECs); and used the estimated PEC for assessing potential risks using Toxicity Exposure Ratios (TER) for selected soil organisms and good agricultural practices. Soil characteristics and environmental variables change along a latitudinal axis through the European continent, influencing the availability of PPP, their toxicity upon soil biota, and hence, impacting on the risk characterization. Although PERSAM includes as input geographical information, the information is aggregated and not further detailed in the model outputs. Therefore, there is a need to develop landscape based environmental risk assessment methods addressing regional variability. The objective was to integrate spatially explicit exposure (PECs) and effect data (biological endpoints i.e. LC50, NOEC, etc.) to estimate the risk quotient (TER) of four PPP active substances (esfenvalerate, cyclaniliprole, picoxystrobin, fenamidone) on non-target species accounting European landscape and agricultural variability. The study was focused on the effects produced by the above-mentioned pesticides on two soil organisms: E. fetida earthworms and Folsomia sp. collembolans. After running PERSAM assuming a worst case application of PPPs, PECs in total soil and pore water were obtained for different depths in northern, central and southern European soils. With this data, soil variability and climatic differences among soils divided in three large Euroregions along a latitudinal transect (Northern, Central, Southern Europe) were analysed. Summarising, a trend to accumulate higher PECs and TERs in total soil was observed in the north decreasing towards the south. Higher PECs and TERs could be expected in pore water in southern soils, decreasing towards the north. The risk disparity between pollutant concentrations at different soils compartments should be taken into account for regulatory purposes, as well as the potential landscape variabilities among different Euroregions.
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Soil contamination has increased significantly over the last few decades due to anthropogenic activities such as industrial waste disposal, agricultural practices, urbanization, construction, mining and drilling, waste dumping, and lack of regulation and enforcement. These activities cause soil contamination with pollutants such as heavy metals, pesticides, industrial chemicals, and pathogens. These pollutants disrupt the food chain, contaminate crops and water, and threaten living beings and the environment. To effectively assess soil pollution, it is essential to establish non-hazardous threshold technologies for determining the quantity of pollutants in the soil. A bio-monitoring approach that focuses on metal toxicity and its availability in the soil, as well as its impact on unidentified metabolites, is appropriate. As a major component of soil biota, earthworms play a crucial role in organic matter decomposition and soil reconstruction in terrestrial ecosystems. Several
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The environment and human health are greatly impacted by heavy metals, and there is an increasing global concern about these potentially dangerous compounds. Heavy metal contamination can have a substantial effect on how the soil ecosystem functions. For this, feasible, effective, and advantageous restorative methods are required. "Ecosystem engineers," as earthworms are called, may alter and enhance the quality of soil. Earthworms might be a valuable biological indicator of soil pollution since they can bioaccumulate significant levels of metals in their tissues. Earthworms are utilized in a novel field of bioremediation research called vermiremediation to purify soils that have been polluted by organic matters. Earthworms have a potent metabolic system, and their propensity to valorize and detoxify heavy metals is mostly due to the gut flora and chloragocyte cells within them. Remediation with earthworms is seen as sustainable, efficient, and friendly to the environment. This review provides in-depth information on earthworms' capacity as possible species for bioremediation and detoxification of heavy metal-polluted soil, addressing problems connected to both human health and the environment. metals in the environment: Bioremediation technique utilizing earthworms for remediating heavy metal-contaminated soil. Intern. J. Zool. Invest. 10(2): 387-409, 2024.
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Soil cadmium (Cd) contamination is an urgent environmental problem, which endangers human health through the food chain. Bioremediation attracted extensive attention around the world due to the high cost-efficiency. However, the remediation efficiency of different plant and earthworm species of soil Cd pollution is still unclear, it is thus of great significance to explore the combined effects of different remediation plants and earthworm species to improve the bioremediation capacity. In the present study, we consequently selected three species of Cd hyperaccumulator plants (vetiver, P. vittata and S. emarginatum) and three species of earthworms (E. fetida P1, E. fetida P2, and P. guillelmi) to compare the differences in Cd accumulation among various earthworm-plant combinations. Results indicated that the changes of soil pH and SOM in plant-animal combined application induced the higher soil Cd removal efficiency. The Cd removal efficiency showed highest in combination groups P. vittata-E. fetida P2 and P. vittata-P. guillelmi. Meanwhile, the improvements of biomass of plants and animals also were consistent with the increasing of Cd concentration in both plants and earthworms after combined application. It showed that the Cd concentrations in P. vittata were the highest while the TFs of Cd in S. emarginatum displays significantly more than that in others. In conclusion, the recommended combined system of earthworm-plant (P. vittata-E. fetida P2 and P. vittata-P. guillelmi) to provide reference for soil Cd bioremediation system in practice.
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Relationships between soil water saturation (SWS) and the accumulation of arsenic (As), cadmium (Cd), and lead (Pb) in soils and aboveground biomass of Populus tremula and Salix caprea were explored. SWS was computed with the hydrological model ParFlow/CLM and compared to data from field observations. Plant and soil samples collected at the main pollution sources contained the highest concentrations of As, Cd, and Pb. S. caprea contained higher concentrations of As, Cd, and Pb than P. tremula. In both species, metal(loid) concentrations in leaves were significantly higher than in branches. At strongly mining-affected locations, metalloid concentration in the trees largely reflected the pollution levels in the soil. In remote study locations, the soil–plant transfer of Cd and Pb was affected by water saturation: element accumulation increased significantly with soil moisture. Results demonstrate that coupling field observations with hydrological modelling is a promising approach for estimating element accumulation.
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Organic solid waste loading emerges as a serious environmental threat. Vermicomposting and composting are the two biological processes having the potential to effectively treat organic waste. In composting, in a controlled environment, microorganisms are used to treat organic wastes. Vermicomposting is a low-cost waste management technique incorporates earthworms and microorganisms to produce highly nutritive vermicompost, which in turn preserves the ecosystem. In vermicomposting, earthworms are the important players, the rate of mineralization is increased and nutritive cast is produced as a byproduct. Vermicompost improves soil aeration, microbial population, soil enzyme activity, and texture while also fostering plant growth. Crop growth and yield are greatly impacted by vermicompost. Vermicast ensures sustainable agricultural practices in addition to improve soil health and plant growth. Adsorption, precipitation, redox reactions, and complexation all work together to make heavy metals unavailable during composting. Heavy metals like mercury, cadmium, lead, copper, zinc, and manganese are bioaccumulated by earthworms. When persistent organic pollutants are composted, microbes take them up and reduce their bioavailability. Through vermicast, earthworms convert microplastics into nanoplastics. This review discusses developments in composting and vermicomposting of organic wastes, the potential contribution of earthworms, presence of heavy metals in organic waste, the influence of biochar on composting and removal of toxic pollutants through composting and vermicomposting.
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Earthworms are considered as the intestine of the soil and play a key role as ecological engineers. The earthworms along with soil were sampled from different regions of Punjab. The soil and earthworm samples were digested using standard protocol and further heavy metal analysis was done through ICP-MS in central Hi-Tech Lab Government College University Faisalabad. The pollution index, bioaccumulation factor and health risk assessment, due to heavy metal contamination, was calculated. The data were subjected to regression analysis to find the relationship between abiotic factors and heavy metals, heavy metal concentration and its bioaccumulation. The highest pollution index was due to cadmium contamination in Bahawalnagar i.e.,4.5. The pollution index of heavy metals shows a trend Cd ≥ Pb ≥ Sr ≥ Fe ≥ Cu ≥ Mn ≥ Co ≥ Cr ≥ Zn ≥ Ni ≥ Ca. The highest bioaccumulation was of Calcium recorded in the region of Faisalabad i.e., 8.18 and lowest bioaccumulation was of Nickel recorded the region of Muzaffargarh is -2.58. The bioaccumulation of other heavy metals shows a trend Mn ≥ Cu ≥ Sr ≥ Zn ≥ Co ≥ Cr ≥ Cd ≥ Fe ≥ Pb ≥ Ni. The highest average daily dose (ADD) was of cadmium through ingestion of soil in Children was found in the region Bahawalnager is 0.002. The maximum hazard quotient (HQ) of was of cadmium through ingestion of soil in children was found in Bahawalnager is 1.13. The highest carcinogenic risk (CR) was due to lead through ingestion of soil in children, was found in the region Muzaffargarh showing 3 persons per 10000 at cancer risk. Most potent impact on BAF has been found of electrical conductivity, including cadmium, followed by moisture and total dissolved solids followed by pH followed by total suspended solids. The lead has negative relationship with BAF of strontium, manganese, cobalt, chromium and cadmium. This study provides an insight regarding bioaccumulation of heavy metals and bioremediation of the soil through earthworms in Punjab Pakistan.
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l-ascorbic acid is found to be an effective and environmentally friendly reagent for remediation of Cr(VI)-contaminated soil. Soil-phase batch kinetics experiments elucidated the effects of chromium(VI) and l-ascorbic acid dosing, pH, soil-to-water ratio, and temperature on Cr(VI) reduction. An extended reductive environment was observed at a lower pH range, possibly due to ligand oxidation of several reactive intermediates. The kinetic data were fitted into a second-order rate model, and the rate constant was evaluated. A reaction mechanism was proposed. Reduction was substantially complete within about 3 h at natural pH conditions at an appropriate dosing of the reagent, and any residual Cr(VI) is reduced by the remaining ascorbic acid during aging of the soil. The reagent worked much better than other organic reductants reported in the literature. The rate constant correlated linearly with the soil-to-water ratio, while its logarithm correlated linearly with pH within the specified range. The reduction was primarily attributed to the presence of carboxylic, hydroxyl, and carbonyl groups in the ascorbic acid molecule, as confirmed by FTIR and XRD analysis. Medium-term stability experiments suggest that treatment with l-ascorbic acid significantly decreased leaching concentrations of Cr(VI) and total Cr which remained stable for 75 d. Ecological studies have shown that remediated soil promotes plant growth and increases earthworm survival rates, thus negating the emergence of any secondary pollutants. Response surface methodology (RSM) was used to investigate the relationship between Cr(VI) reduction and experimental parameters and to determine the optimum values. About 98.8 % reduction was achieved, which was consistent with the calculated optimal value. The study provides new insights into the use of l-ascorbic acid for sustainable remediation of Cr(VI)-contaminated soil. The optimum process conditions and the rate data obtained in this study are expected to be useful for the process design of a remediation facility for Cr(VI)-contaminated soil.
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Встановлено, що порушення ґрунтів внаслідок воєнних дій можуть носити довгостроковий характер та становити небезпеку для населення та територій. Процес моделювання поширення забруднювачів є складним завданням через необхідність врахування багатьох змінних, як у часі, так і у просторі. На сьогодні не створено універсальних методологій оцінки безпеки ґрунтів територій, які зазнали воєнного впливу, та підходів щодо допустимого рівня їх забруднень. Сформовані базові методологічні критерії досліджень з попередження надзвичайних ситуацій на територіях, які зазнали ракетно-артилерійських уражень.
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Heavy metals pose serious threats to both individuals and the environment, and there is growing global concern over potentially harmful elements. Heavy metal contamination can have a significant impact on the soil ecosystem's functioning. This requires convenient, efficient, and beneficial remediation approaches. The "ecosystem engineer", earthworms, can modify and enhance soil quality. The ability of earthworms to bioaccumulate metals in substantial amounts in their tissues makes them potentially beneficial as an ecological indicator of soil pollution. Vermiremediation is a new discipline of research in which earthworms are used to detoxify organically contaminated soils. Earthworms have an influential metabolic system, and their gut bacteria and chloragocyte cells play a significant role in their tendency to valorize and detoxify heavy metals. Remediation by earthworms can be considered sustainable, efficient, and ecologically beneficial. The present review provides a wide range of information on earthworms' appropriateness as prospective species for bioremediation and detoxification of toxic metal-contaminated soil to mitigate human health and environmental problems.
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Environmental pollution has become a pressing concern worldwide due to the accumulation of pollutants from industries and agricultural sectors in soil and water environments. Heavy metals pose severe hazards to the environment, plants, and human health. Consequently, an eco-friendly technique is needed to combat environmental pollutants. Vermibiochar, a product prepared through the combined action of earthworms and biochar, demonstrates great potential in reducing heavy metal concentrations in contaminated soil. Its large surface area and high cation exchange capacity enhance the sorption of contaminants onto the vermibiochar surface, reducing their bioavailability. This review highlights the roles played by earthworms and biochar in heavy metal detoxification and immobilization. It discusses the current methods of remediation, vermibiochar production, its effects on soil properties and plant growth, and biochar’s impact on earthworm growth and reproduction. The studies reviewed suggest that vermibiochar is a novel strategy for addressing heavy metal contamination.
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Elevated heavy metal concentrations in soils is a cause for concern as they are hazardous to soil organisms including earthworms which are considered as ecosystem engineers. Current ecotoxicity tests predominantly use temperate earthworm species, and thus there is the need to include a broader genera of native species to improve ecological risk assessment. Alma nilotica , is a tropical anecic earthworm species that survives well under laboratory conditions and has potential for use in ecotoxicology testing but lacks published toxicity data for important pollutants. Growth and reproduction bioassays were carried out with Alma nilotica to determine the relationship between the concentrations of Cu, Zn, Pb and Cr in spiked soils and their bioaccumulation and toxic effects. Positive linear relationships were found between soil-metal and internal earthworm-metal concentrations. Cu did not inhibit growth up to 35 days of exposure but became toxic with longer exposure duration. Zn was not regulated by Alma nilotica although it is an essential metal that is well regulated by Eisenia sp. commonly used in standard ecotoxicity tests, showing differences in metal regulation by earthworms of different ecological functional groups. Based on bioaccumulation factors (BAFs), growth inhibition and reproduction effects the metals were ranked in decreasing toxicity as Pb > Cr > Zn > Cu. The mean 20% Internal Effects Concentrations (IEC20s) for reproduction were 1.03. 1.77, 10.2 and 218 mg metal/kg earthworm for Pb, Cr, Zn and Cu respectively. These data can contribute to the improvement of metal risk assessment particularly in tropical contexts.
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Metal contamination is widespread, but only a few studies have evaluated the toxicological risks of metals (Cd, Cu, and Pb) in earthworms from farmlands in North China (Hebei province). Amynthas hupeiensis, the dominant species in the study area, was used to determine the responses and detoxification mechanisms of uncontaminated (CK), and low (LM)-, and high (HM)-metal-contaminated soils following 7-, 14-, and 28-days exposure. Metal toxicity in LM and HM soils inhibited the biomass of A. hupeiensis. The concentrations of Cd in A. hupeiensis bodies indicated accumulated Cd appeared to remain steady with prolonged exposure, while Cu/Pb increased significantly with soil levels. Bioaccumulation occurred in the order Cd > Pb > Cu in LM soil, and in the order Cd > Cu ≈ Pb in HM soil, which was attributed to differences in available fractions between LM and HM soils. Physiological levels of biomarkers in A. hupeiensis were determined, including total protein (TP), glutathione (GSH), glutathione peroxidase (GPx), acetylcholinesterase (AChE), and malondialdehyde (MDA). Deviations in GSH, GPx, and AChE were considered to denote sensitive biomarkers using the IBRv2 index. Metabolomics data (1H nuclear magnetic resonance-based) revealed changes in metabolites following 28-days exposure to LM and HM soils. Differences in metabolism in A. hupeiensis following exposure to LM and HM were related to energy metabolism, amino acid biosynthesis, glycerophospholipid metabolism, inositol phosphate metabolism, and glutathione metabolism. Metal stress from LM and HM soils disturbed osmoregulation, resulting in oxidative stress, destruction of cell membranes and inflammation, and altered levels of amino acids required for energy by A. hupeiensis. These findings provide biochemical insights into the physiological and metabolic mechanisms underlying the ability of A. hupeiensis to resist metal stress, and for assessing the environmental risks of metal-contaminated soils in farmland in North China.
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Soil contaminated with hexavalent chromium seriously threatens the environment and human health. The use of FeS, which has a high redox activity and excellent reduction capacity, limits its application in soil remediation due to its premature surface oxidation and massive aggregation. To prevent premature surface oxidation and agglomeration, cetyltrimethylammonium bromide-supported nano-ferrous sulfide (CTAB-nFeS) was chemically synthesized and used for immobilizing Cr(VI) in contaminated soil. In order to evaluate the role of CTAB stabilization of nFeS and interaction mechanisms were investigated by XPS, FTIR, XRD, and FESEM. Batch experiments showed a complete reduction of Cr(VI) within 3 h with only 235% excess of CTAB-nFeS at a soil pH of 8 compared to days as reported in the literature with alternative FeS forms. The reduction kinetic data could be satisfactorily fitted into the second-order rate model. The rate constant linearly depends on the soil-to-water ratio, but its logarithmic form is linear in the given pH range. The oxidation-reduction potential increases with decreasing initial pH, thus positively impacting the reduction process. XPS analysis revealed the reduction process as multi-steps (reduction, adsorption, and co-precipitation). Ecological studies showed improved plant growth and earthworm survival rate in the remediated soil. Medium-term stability experiments suggested a significant decrease in TCLP leachate concentration of Cr after CTAB-nFeS treatment and remained stable for 60 d. Overall results of our study suggested a sustainable, feasible, and effective strategy for in-situ remediation of Cr(VI)-contaminated soil using CTAB-nFeS at natural pH.
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Present study is aimed to evaluate the influence of earthworm (Eisenia fetida), Cyanobacteria (Cylindrospermum stagnale), and rice husk biochar (BC) on cadmium (Cd) detoxification in artificially contaminated soil. The Cd content was kept at 10 mg/kg in factorial design I, coupled with 2% and 0% BC. E. fetida and C. stagnale un-inoculated and inoculated experiments were maintained respectively as negative and positive controls. In factorial design II, E. fetida and C. stagnale were inoculated, along with BC (0% and 2%, denoted as B), without BC (WB), along with four different Cd concentrations (Cd-0, Cd-5, Cd-10, and Cd-20 mg/kg). Results suggest a substantial amount of Cd removal in BC-assisted treatments when compared to negative control-1. Cd (mg/g) in E. fetida tissue ranged from 0.019 (WB2) to 0.0985 (B4). C. stagnale of WB4 (0.036) bioaccumulated the most Cd (mg/g), while B2 showed the least (0.018). The maximum quantity of metallothionein (5.34 μM/mg) was detected in E. fetida of B4 (factorial design – II) and the minimum was claimed in WB1 (0.48 μM/mg) at the end. Earthworm metallothionein protein is a key component in Cd removal from soil by playing an important role in detoxification process. Microbial communities and humic substances were observed in BC-assisted treatments, which aided in Cd-contaminated soil remediation. The present findings suggest that BC (2%) + earthworms + algae could be a suitable remediation strategy for Cd contaminated soil. BC + earthworm + algal-based investigation on heavy metal remediation will be a valuable platform for detoxifying harmful metals in soils.
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Atrazine has been widely used in the world and caused environmental pollution, especially soil pollution. When assessing the toxicity of atrazine in soil, most studies used standardized artificial soils, while few studies focused on the real soil environments. In the present study, three natural soils and artificial soil were selected as test soils to study and compare the toxicities of atrazine to Eisenia fetida. Acute toxicity of atrazine was determined by filter paper and soil tests. In chronic toxicity study, after atrazine exposure, the content of reactive oxygen species in Eisenia fetida significantly increased and showed a dose-response relationship. The activity changes of three antioxidant enzymes and glutathione transferase showed that atrazine had obvious oxidative stress effect on earthworms. The contents of malondialdehyde and 8-hydroxy deoxyguanosine in 0.1 and 1 mg/kg atrazine treatment groups were significantly higher than the control, indicating that medium and high concentrations of atrazine could cause lipid and DNA damage in Eisenia fetida. The acute toxicity results and the integrated biomarker response index for chronic toxicity indicated that the toxicity order of atrazine was: red clay > fluvo-aquic soil > artificial soil > black soil, and that the toxicity of atrazine in artificial soil was not representative of its toxicity in real soil environment. The results of correlation analysis showed that three soil property parameters of organic carbon, organic matter and sand were most related to the toxicity of atrazine.
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The organic manures contain large proportion of organic matter, small quantities of plant nutrients and play pivotal role in improving the soil physical, chemical and biological properties. The use of FYM and compost in agriculture is an age old practice to improve crop productivity. The inoculations of microorganisms in soil are also beneficial for maintaining soil health though decomposition of organic matter, N fixation, solubilization/mineralization, production of antibiotics and plant growth regulators etc. In the paper, the roles of vermicompost, FYM and biofertilizers on crop productivity and soil health have been discussed in detail. The bioxidation and stabilization of organic material by using earthworms and mesophilic microorganisms is known as vermicomposting. The vermicompost applications in soil stimulate soil microbial activity and mineralization processes. The application of FYM and vermicompost boost the activities of beneficial soil microorganisms and improve the supply of mineral nutrients, soil structure, water retention capability and enzymatic activities. Seed or soil inoculated biofertilizers promotes the nutrient cycling and improves crop productivity with two ways i.e. direct - N fixation, solubilization of nutrients production of phytohormones, indirect – development of resistance in plant against the stress and diseases and heavy metals bioremediation. The use of manures along with biofertilizers in farming ensures the improvement in soil biodiversity and food safety for human consumption. The use of manures in agriculture is essential for sustainable production systems and to keep the soil alive and healthy.
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Heavy metal contamination in lake sediments is a serious problem, particularly in developing countries such as China. To evaluate heavy metal pollution and risk of contamination in lake sediments on a national scale in China, we collated available data in the literature of the last 10 years on lake sediments polluted with heavy metals from 24 provinces in China. Based on these data, we used sediment quality guidelines, geoaccumulation index, and potential ecological risk index to assess potential ecological risk levels. The results showed that approximately 20.6% of the lakes studied exceeded grade II level in Chinese soil quality standards for As, 31.3% for Cd, 4.6% for Cu, 20.8% for Ni, 2.8% for Zn, and 11.1% for Hg, respectively. Besides, the mean concentrations for As in 10.3% of lakes, Hg in 11.9% of lakes, and Ni in 31.3% of lakes surpassed the probable effect level. The potential ecological risk for toxic metals decreased in the order of Cd > Hg > As > Cu > Pb > Ni > Cr > Zn, and there were 21.8% of the lakes studied in the state of moderate risk, 10.9% in high risk, and 12.7% in very high risk. It can be concluded that Chinese lake sediments are polluted by heavy metals to varying degrees. In order to provide key management targets for relevant administrative agencies, based on the results of the pollution and ecological risk assessments, Cd, Hg, As, Cu, and Ni were selected as the priority control heavy metals, and the eastern coastal provinces and Hunan province were selected as the priority control provinces. This article, therefore, provides a comprehensive assessment of heavy metal pollution in lake sediments in China, while providing a reference for the development of lake sediment quality standards.
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Soil pollution at firing ranges is an issue of growing importance, due to the accumulation in soils of contaminants derived from ammunition and clay targets. The concentration of Pb and PAHs was determined in five soils of an abandoned shooting range in Galicia (northwest Spain), and an ecotoxicological characterization was performed in order to obtain an assessment of risks. Therefore, the retention capacity of soils was assessed using test organisms of different trophic levels, and the role of soils as habitat for soil invertebrates was assessed by reproduction tests and bioaccumulation assays with earthworms. The sum of 15 PAHs ranged between 38 and 360mgkg(-1), which exceed, together with Pb (160-720mgkg(-1)), the Galician generic reference value for urban and sporting field soils. Bioaccumulation in E. andrei showed contents up to 104,000μgPbkg(-1)dw, and up to 645μgPAHskg(-1)fw. High contents of Pb and PAHs in soil samples and in Eisenia andrei whole body, caused a reduction in the number of juveniles produced, whereas, Vibrio fischeri, Raphidocelis subcapitata and Daphnia magna displayed a slight toxic response to the soil elutriates tested. Therefore, the function of these soils to retain contaminants seemed not compromised, probably due to the high organic matter content and pH values, which are weakly acidic. The habitat function was affected, indicating that soil solution is not the only route of exposure to contaminants to E. andrei. The integration of chemical and ecotoxicological lines of evidence give rise to high risks values, restricting the use of these areas, and pointing for risks to surrounding ecosystems due to possible trophic transferences. The calculation of risks using the chemical and ecotoxicological data, required by Spanish legislation, could be a good approach to communicate with those responsible and/or involved in the management of contaminated sites.
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The invasion of the pheretimoid earthworms in North America, especially the genera Amynthas and Metaphire, has raised increasing concerns among ecologists and land managers, in turn increasing the need for proper identification. However, the commonly used keys to this group are more than 30 years old with outdated taxonomic information and are based primarily on internal morphology. The requirement of significant amount of taxonomic expertise and dissection, even from the first entry of the key, has prevented broader use of these keys. As a result, many publications in the United States have used Amynthas spp. to represent the group without identifying the species. We present here a new key and diagnoses for the 16 pheretimoid earthworm species recorded in North America north of Mexico, including four genera: Amynthas (10), Metaphire (4), Pithemera (1), and Polypheretima (1). The descriptions were based on published records with modifications following inspection of specimens archived at the National Museum of Natural History, Smithsonian Institution, Washington, D.C. Photos of external and internal characters, including male pores, spermathecal pores, genital markings, spermathecae, prostate glands, and intestinal caeca, are presented to help identification. A summary of current knowledge about the ecology and historical context is provided for each species. We also highlight the previously overlooked, and potentially common and widespread co-occurrence of three species-A. agrestis, A. tokioensis, and M. hilgendorfi-and point out that many recent claims of invasion of A. agrestis need to be re-evaluated for potential misidentification.
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The Pheretima complex within the Megascolecidae family is a major earthworm group. Recently, the systematic status of the Pheretima complex based on morphology was challenged by molecular studies. In this study, we carry out the first comparative mitogenomic study in oligochaetes. The mitogenomes of 15 earthworm species were sequenced and compared with other 9 available earthworm mitogenomes, with the main aim to explore their phylogenetic relationships and test different analytical approaches on phylogeny reconstruction. The general earthworm mitogenomic features revealed to be conservative: all genes encoded on the same strand, all the protein coding loci shared the same initiation codon (ATG), and tRNA genes showed conserved structures. The Drawida japonica mitogenome displayed the highest A + T content, reversed AT/GC-skews and the highest genetic diversity. Genetic distances among protein coding genes displayed their maximum and minimum interspecific values in the ATP8 and CO1 genes, respectively. The 22 tRNAs showed variable substitution patterns between the considered earthworm mitogenomes. The inclusion of rRNAs positively increased phylogenetic support. Furthermore, we tested different trimming tools for alignment improvement. Our analyses rejected reciprocal monophyly among Amynthas and Metaphire and indicated that the two genera should be systematically classified into one.
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The rhizosphere plays an important role in altering cadmium (Cd) solubility in paddy soils and Cd accumulation in rice. However, more studies are needed to elucidate the mechanism controlling rice Cd solubility and bioavailability under different rhizosphere conditions to explain the discrepancy of previous studies. A rice culture with nutrient solution and vermiculite was conducted to assess the effects of pH, Eh, and iron (Fe) concentration on Cd, Fe fractions on the vermiculite/root surface and their uptake by rice. The solution pH was set from 4.5 to 7.5, with additions of Fe (30 and 50 mg L−1) and Cd (0.5 and 0.9 mg L−1). At pH 5.5, the Eh in the rice rhizosphere was higher whereas transpiration, Cd2+, and Fe2+ adsorption on the vermiculite/root surface and accumulation in rice were lower than the other pH treatments. Cadmium addition had no impact on pH and Eh in rice rhizosphere while Fe addition decreased pH and increased Eh significantly. Compared with control, Fe addition resulted in the decrease of rhizosphere Cd, Fe solubility and bioavailability. Higher redox potential in the rice rhizosphere resulted in the decline of transpiration, Cd, and Fe accumulation in the rice tissues, suggesting that the transfer of two elements from soil to rice was depressed when the rhizosphere was more oxidized.
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As, Cd, Cu, Pb, Sb and Zn concentrations were determined in two earthworm species (Allolobophora rosea and Nicodrilus caliginosus) from a mining and industrial area in northern Kosovo and compared with their contents in the bulk soil and the main soil fractions. Earthworm specimens were collected at fifteen sites located at different distances from a Pb–Zn smelter along a gradient of decreasing contamination. Individuals of A. rosea and N. caliginosus showed similar tissue levels of As, Cd, Cu, Pb, Sb and Zn, suggesting that earthworm species belonging to the same eco-physiological group have a similar propensity to uptake and bioaccumulate heavy elements. Cd, Pb, Sb and Zn concentrations in both earthworm species were positively correlated with the respective total soil contents and generally decreased with distance from the smelter. The bioaccumulation factor (BAF) revealed that Cd and Zn were the only elements bioaccumulated by earthworms. The rank order of BAF values for both species was as follows: Cd>>Zn>>Cu>As=Pb=Sb. The absorption of Cd, Pb, Sb and Zn by earthworms mostly depended on the extractable, reducible and oxidable soil fractions, suggesting that the intestine is likely the most important uptake route. The extractable soil fraction constantly influenced the uptake of these heavy elements, whereas the reducible fraction was important mainly for Pb and Zn. The water soluble fraction had an important role especially for the most mobile heavy elements such as Cd and Zn, suggesting that dermal uptake is not negligible. As a whole, the analytical data indicate that soil fractionation patterns influence the uptake of heavy elements by earthworms, and the extractable fraction is a good predictor of heavy element bioavailability to these invertebrates in soil.
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Collections made in montane forests of the Bicol region of the Philippine island Luzon contained earthworm species new to science. The new genus Dendropheretima has intestinal caeca paired in xxv, lamellar oesophageal pouches in xi‐xiii, testes free of sacs, and last hearts in xii. The two species, D. banahawensis and D. bicolensis, are both arboreal. A second new genus Isarogoscolex contains two species, Isarogoscolex abiadai and I. albayensis which are also arboreal but have more posteriorly located caeca and more pairs of caeca, have only meganephridia in the intestinal segments, and the lamellar oesophageal pouches are arranged differently from Dendropheretima. Among the other genera of the Pheretima complex, these new taxa may be closest to the Australo‐Papuan Begemius.
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Examination of new earthworm material from Cape York Peninsula, Queensland, revealed the presence of five new species (one with two subspecies) of the Pheretima group of genera, family Megascolecidae. A new genus, Begemius, is erected to contain the new taxa (B. gavini, jamiesoni jamiesoni, j. hornensis, lockerbiensis, raveni and yorkensis), also the species cyclops, monoperus and queenslandicus which were previously accommodated in the genus Amynthas. A key is provided to the eight species in the genus and the Australian members are described. Other new pheretimoid material from Northern Territory, Queensland, Western Australia and New South Wales consists of allochthonous species only, representing new locality records and including four species, Amynthas gracilis, A. morrisi, Metaphire bahli and Pithemera bicincta, new to the Australian list. These species and the other eight allochthonous species of the Pheretima group reported from Australia, Amynthas corticis, A. minimus, A. rodericensis, Metaphire californica, M. houletti, Pheretima darnleiensis, Polypheretima elongata and P. taprobanae are reviewed, each is diagnosed and a key is provided for their identification.
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Due to diffuse atmospheric fallouts of process particles enriched by metals and metalloids, polluted soils concern large areas at the global scale. Useful tools to assess ecotoxicity induced by these polluted soils are therefore needed. Earthworms are currently used as biotest, however the influence of specie and earthworm behaviour, soil characteristics are poorly highlighted. Our aim was therefore to assess the toxicity of various polluted soils with process particles enriches by metals and metalloids (Pb, Cd, Cu, Zn, As and Sb) collected from a lead recycling facility on two earthworm species belonging to different ecological types and thus likely to have contrasted behavioural responses (Eiseina hortensis and Lumbricus terrestris). The combination of behavioural factors measurements (cast production and biomass) and physico-chemical parameters such as metal absorption, bioaccumulation by earthworms and their localization in invertebrate tissues provided a valuable indication of pollutant bioavailability and ecotoxicity. Soil characteristics influenced ecotoxicity and metal uptake by earthworms, as well as their soil bioturbation.
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Earthworm specimens collected in southern Taiwan consisted of seven new species of Amynthas and several previously known species, mostly widely distributed peregrines. The new species are A. nanrenensis of the octothecal A. corticis species group, A. monsoonus and A. huangi of the sexthecal A. aelianus species group, and four proandric octothecal species: A. chaishanensis, A. hengchunensis, A. kaopingensis and A. ailiaoensis. Amynthas chaishanensis has dorsal intrasegmental spermathecal pores, but the other three proandric species have dorsal, lateral or ventral intersegmental spermathecal pores, respectively. The proandric species are united by several features, including the enclosure of segment xi in a sac, as in A. formosae (also proandric), octothecal with spermathecae in vi–ix, spermathecal diverticula stalks generally kinked and often enclosed in membrane, and prostatic ducts divided polytomously into numerous small ductlets, which may be grouped into bundles of two to five. In A. ailiaoensis the prostatic duct trunk contains up to seven separate lumens in the ental half, surrounded by the circular muscle of the duct, while in A. chaishanensis the prostatic duct trunk contains about 40 small lumens. Of the previously known species in the collection, Pontodrilus litoralis and Metaphire houlleti are first reported from Taiwan. Additional locations for A. incongruus and A. robustus are given, and in the latter case the material appears to be the usual male‐sterile morph. Other species found are Pontoscolex corethrurus, Amynthas corticis, A. gracilis, Metaphire californica, and Polypheretima elongata.
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Fine and ultrafine metallic particulate matters (PMs) are emitted from metallurgic activities in peri-urban zones into the atmosphere and can be deposited in terrestrial ecosystems. The foliar transfer of metals and metalloids and their fate in plant leaves remain unclear, although this way of penetration may be a major contributor to the transfer of metals into plants. This study focused on the foliar uptake of various metals and metalloids from enriched PM (Cu, Zn, Cd, Sn, Sb, As, and especially lead (Pb)) resulting from the emissions of a battery-recycling factory. Metal and metalloid foliar uptake by various vegetable species, exhibiting different morphologies, use (food or fodder) and life-cycle (lettuce, parsley and rye-grass) were studied. The mechanisms involved in foliar metal transfer from atmospheric particulate matter fallout, using lead (Pb) as a model element was also investigated. Several complementary techniques (micro-X-ray fluorescence, scanning electron microscopy coupled with energy dispersive X-ray microanalysis and time-of-flight secondary ion mass spectrometry) were used to investigate the localization and the speciation of lead in their edible parts, i.e. leaves. The results showed lead-enriched PM on the surface of plant leaves. Biogeochemical transformations occurred on the leaf surfaces with the formation of lead secondary species (PbCO(3) and organic Pb). Some compounds were internalized in their primary form (PbSO(4)) underneath an organic layer. Internalization through the cuticle or penetration through stomata openings are proposed as two major mechanisms involved in foliar uptake of particulate matter.
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This paper reviews quite a few heavy metal contamination related studies in several cities from China over the past 10 years. The concentrations, sources, contamination levels, sample collection and analytical tools of heavy metals in urban soils, urban road dusts and agricultural soils were widely compared and discussed in this study. The results indicate that nearly all the concentrations of Cr, Ni, Cu, Pb, Zn, As, Hg and Cd are higher than their background values of soil in China. Among the cities, the contamination levels of the heavy metals vary in a large range. The geoaccumulation index shows that the contamination of Cr, Ni, Cu, Pb, Zn and Cd is widespread in urban soils and urban road dusts of the cities. Generally, the contamination levels of Cu, Pb, Zn and Cd are higher than that of Ni and Cr. Agricultural soils are also significantly influenced by Cd, Hg and Pb derived from anthropogenic activities. The integrated pollution index (IPI) indicates that the urban soils and urban road dusts of the developed cities and the industrial cities have higher contamination levels of the heavy metals. The comparison of the IPIs of heavy metals in urban soils and urban road dusts of Shanghai, Hangzhou, Guangzhou and Hongkong reveals that the contamination levels of the metals in urban road dusts are higher than that in urban soils in the cities. Moreover, the main sources of the metals in urban soils, urban road dusts and agricultural soils are also different.
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New methods are needed for research into non-model organisms, to monitor the effects of toxic disruption at both the molecular and functional organism level. We exposed earthworms (Lumbricus rubellus Hoffmeister) to sub-lethal levels of copper (10-480 mg/kg soil) for 70 days as a real-world situation, and monitored both molecular (cDNA transcript microarrays and nuclear magnetic resonance-based metabolic profiling: metabolomics) and ecological/functional endpoints (reproduction rate and weight change, which have direct relevance to population-level impacts). Both of the molecular endpoints, metabolomics and transcriptomics, were highly sensitive, with clear copper-induced differences even at levels below those that caused a reduction in reproductive parameters. The microarray and metabolomic data provided evidence that the copper exposure led to a disruption of energy metabolism: transcripts of enzymes from oxidative phosphorylation were significantly over-represented, and increases in transcripts of carbohydrate metabolising enzymes (maltase-glucoamylase, mannosidase) had corresponding decreases in small-molecule metabolites (glucose, mannose). Treating both enzymes and metabolites as functional cohorts led to clear inferences about changes in energetic metabolism (carbohydrate use and oxidative phosphorylation), which would not have been possible by taking a 'biomarker' approach to data analysis. Multiple post-genomic techniques can be combined to provide mechanistic information about the toxic effects of chemical contaminants, even for non-model organisms with few additional mechanistic toxicological data. With 70-day no-observed-effect and lowest-observed-effect concentrations (NOEC and LOEC) of 10 and 40 mg kg-1 for metabolomic and microarray profiles, copper is shown to interfere with energy metabolism in an important soil organism at an ecologically and functionally relevant level.
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The causation between bioavailability of heavy metals and environmental factors are generally obtained from field experiments at local scales at present, and lack sufficient evidence from large scales. However, inferring causation between bioavailability of heavy metals and environmental factors across large-scale regions is challenging. Because the conventional correlation-based approaches used for causation assessments across large-scale regions, at the expense of actual causation, can result in spurious insights. In this study, a general approach framework, Intervention calculus when the directed acyclic graph (DAG) is absent (IDA) combined with the backdoor criterion (BC), was introduced to identify causation between the bioavailability of heavy metals and the potential environmental factors across large-scale regions. We take the Pearl River Delta (PRD) in China as a case study. The causal structures and effects were identified based on the concentrations of heavy metals (Zn, As, Cu, Hg, Pb, Cr, Ni and Cd) in soil (0–20 cm depth) and vegetable (lettuce) and 40 environmental factors (soil properties, extractable heavy metals and weathering indices) in 94 samples across the PRD. Results show that the bioavailability of heavy metals (Cd, Zn, Cr, Ni and As) was causally influenced by soil properties and soil weathering factors, whereas no causal factor impacted the bioavailability of Cu, Hg and Pb. No latent factor was found between the bioavailability of heavy metals and environmental factors. The causation between the bioavailability of heavy metals and environmental factors at field experiments is consistent with that on a large scale. The IDA combined with the BC provides a powerful tool to identify causation between the bioavailability of heavy metals and environmental factors across large-scale regions. Causal inference in a large system with the dynamic changes has great implications for system-based risk management.
Article
Contaminated soil is a problem throughout the industrialized world, and a significant proportion of these sites are polluted with heavy metals such as copper. Ecological risk assessment of contaminated sites requires ecotoxicological studies with spiked soils as well as in-situ ecological observations. Here, we report laboratory and field assessment of copper toxicity for earthworms at a Danish site (Hygum) exclusively contaminated with an increasing gradient in copper from background to highly toxic levels (>1000 mg kg⁻¹ dry soil). More specifically, we report effects on field populations, body contents of copper, hatching of earthworm cocoons and reproduction of the common species Aporrectodea tuberculata. Abundance of earthworms and cocoons decreased significantly from about 400–150 m⁻² along the gradient as the soil copper concentration increased from ca. 50 to ca. 1000 mg kg⁻¹. At lower concentrations, the population was dominated by endogeic species, whereas at high concentrations the population was dominated by epigeic species. At high copper contents the internal concentration of copper was in the range 100–160 mg kg⁻¹ dry tissue. Despite the high internal copper contents, hatchability of field collected cocoons was not impaired in any species. The EC50 reproduction value of A. tuberculata was about 220 mg copper kg⁻¹ dry soil in the first two exposure periods, but nearly doubled in the third period suggesting that an acclimation response had occurred. Also in the laboratory reproduction test, cocoon hatchability was not reduced, but rather slightly stimulated by copper. Based on these results we discuss the possibility that acute exposure in laboratory experiments is more detrimental than exposure in a field situation, perhaps because increased tolerance may be acquired through natural selection and genetic adaptation through increased use of defense mechanisms such as metallothioneins. Further, we discuss that the rather high tissue copper level of earthworms from the Hygum site may have smaller effects in these free-ranging worms than it would have in acute-exposure laboratory tests because the copper is more efficiently sequestered and detoxified in the field situation where populations have been exposed for many generations.
Article
The study assessed the long-term effects of anthropogenic pressure of the sulfur industry on turf-covered soils located in the vicinity of the sulfur mine Grzybów. The study assumes that 20 years which elapsed since the end of the exploitation of sulfur is a period sufficiently long for the content of sulfur compounds in soils not to exceed the permissible level and that soil of the region can be classified as not contaminated. A part of the study involved identification of changes in the contents Stot. and SSO42− in soils collected in the 1970s and early twenty-first century. It was also traced the relationship between the content of sulfur compounds and selected soil properties and estimated risk of soil environment pollution by heavy metals. Mean contents of trace elements studied amounted to 10.2–10.8 mg kg−1 for Pb, 14.3–39.4 mg kg−1 for Zn, 0.2–0.4 mg kg−1 for Cd, 3.8–32.2 mg kg−1 for Cr, 2.7–15.1 mg kg−1 for Cu and 2.9–18.7 mg kg−1 for Ni. Based on the results of SSO42− content in soils collected at a distance of 1 km from the mine, it was found out that despite the passage of years, the amount of this type of sulfur still is increased and exceeds 0.14 g kg−1. As the distance from the mine grew lower (from 0.017 to 0.03 g kg−1) average content of the sulfur form was observed. In the studied soil material we found generally positive, strong correlation between the Stot. and SSO42− content and analyzed trace elements. The degree of contamination of examined soils with heavy metals was estimated on the basis of the integrated pollution index, which pointed to a moderate and low level of antropogenization of this area. In addition, the relationship between the determined characteristics of soils (Corg. contents, the fraction <0.002 mm and pH) and heavy metals confirms that the trace elements present in soils do not occur in mobile forms in the soil solution.
Article
Earthworms are abundant and ecologically very important organisms in the soil ecosystem. Impacts by pollutants on earthworm communities greatly influence the fertility of the terrestrial environment. In ecotoxicology, earthworms are good indicators of metal pollution. The observed median lethal concentrations (LC50) and the effective concentrations that cause 50 % reduction of earthworm growth and reproduction (EC50) are referred to as toxicity concentrations or endpoints. In addition, the 'no observed effective concentration' (NOEC) is the estimation of the toxicity of metals on earthworms expressed as the highest concentration tested that does not show effects on growth and reproduction compared to controls. This article reviews the ecotoxicological parameters of LC50, EC50 and NOEC of a set of worms exposed to a number of metals in various tested media. In addition, this article reviews metal accumulation and the influences of soil characteristics on metal accumulation in earthworms. Morphological and behavioural responses are often used in earthworm toxicity studies. Therefore, earthworm responses due to metal toxicity are also discussed in this article.
Article
China faces great challenges in protecting its soil from contamination caused by rapid industrialization and urbanization over the last three decades. Recent nationwide surveys show that 16% of the soil samples, 19% for the agricultural soils, are contaminated based on China's soil environmental quality limits, mainly with heavy metals and metalloids. Comparisons with other regions of the world show that the current status of soil contamination, based on the total contaminant concentrations, is not worse in China. However, the concentrations of some heavy metals in Chinese soils appear to be increasing at much greater rates. Exceedance of the contaminant limits in food crops is widespread in some areas, especially southern China, due to elevated inputs of contaminants, acidic nature of the soil and crop species or cultivars prone to heavy metal accumulation. Minimizing the transfer of contaminants from soil to the food chain is a top priority. A number of options are proposed, including identification of the sources of contaminants to agricultural systems, minimization of contaminant inputs, reduction of heavy metal phytoavailability in soil with liming or other immobilizing materials, selection and breeding of low accumulating crop cultivars, adoption of appropriate water and fertilizer management, bioremediation, and change of land use to grow non-food crops. Implementation of these strategies requires not only technological advances, but also social-economic evaluation and effective enforcement of environmental protection law.
Article
Chu-Fa Tsai, Huei-Ping Shen and Su-Chen Tsai (2000) Native and exotic species of terrestrial earthworms (Oligochaeta) in Taiwan with reference to Northeast Asia. Zoological Studies 39(4): 285-294. Of the 35 nominal species of terrestrial earthworms (Oligochaeta) reported from Taiwan, there are 30 species of the Megascolecidae, two species of the Lumbricidae, and 1 species each for the Moniligastridae, Glossoscolecidae, and Octochaetidae. The genera Amynthas and Metaphire of the Megascolecidae are dominant and include 27 species, of which 12 species are native. Among these 35 species, the 12 native species occur primarily in hills and mountains of the island, where natural environments (forests) still remain, or in areas relatively less disturbed by humans. The other 23 species are exotic, including 4 species with presumed origins from America and Europe, four species from Southeast Asia, and 15 species from southern China. They occur in disturbed environments (urban areas and cultivated lands) on the plains and in some hill and mountainous areas. Endemism based on the nominal species in Taiwan is 34.3%, which is much lower than 74.2% for Hainan Island, 78.1% for China, 65.0% for Japan, 60.0% for Korea, and 37.0% for the Ryukyus. The native species of Amynthas and Metaphire in Taiwan are apparently offshoots of the oligochaete fauna of southern China, resulting from dispersion differentiation.
Article
This paper presents an up-to-date list of the terrestrial earthworms of Hainan Island, which is the second largest island of China and separated by Qiongzhou Strait from the Leizhou Peninsula, Guangdong Province. Actually, 45 species are already known in this island, 60% of which is native species. Ten new species which were collected in the fieldwork in 2006 are also included in the list. Of these 45 species, 82% belongs to the family Megascolecidae, with the dominant genus Amynthas (70%). Some of the species also disperse in other regions of the Southeast Asia and China mainland, except 5 species only have a limited distribution. The endemism rate of Hainan (60%) is similar with that of China mainland (66%) and Taiwan (58%), but its endemism rate of Amynthas (77%) is much higher. All of these results maybe have some links with the geographical history of Hainan Island.
Article
The earthworm Eisenia fetida avoidance behaviour test was used to assess the quality recovery of metal-contaminated soils from lands submitted for 10 years to remediation. Soils were from plots located in the surroundings of a former lead smelter plant of Northern France. Metal concentrations in the soils ranged from 93 to 1231, 56 to 1424, 0.3 to 20 and 15 to 45.5mg metal/kg dry soil for Pb, Zn, Cd and Cu, respectively. Several former agricultural plots were treated either by a single phytostabilisation process involving the plantation of a tree mix or by fly ash aided-phytostabilisation. Silico-aluminous or sulfo-calcic ashes used were ploughed up to a 25- to 30-cm soil depth at a rate of 23.3kg/m(2) (i.e., 6 percent W/W). E. fetida was shown to avoid significantly the 10 years ash-treated soils whose habitat function has to be considered as limited. This avoidance would relate to a change of the texture of soils induced by the addition of ashes and consisting in an increased level of fine silts together with a decreased level of clays. By contrast, afforested metal-contaminated soils appeared for E. fetida as more attractive than unplanted ones. Regarding the influence of the metal contamination of the soils on E. fetida, none of the soils tested even the highest contaminated one was significantly avoided by worms. This lack of reaction would result from the low bioavailability of the metals in the soils tested. At the lights of our results and those previously published on both these ashes and these ash-treated soils, the usefulness of these soil treatments is discussed.
Article
This paper reports the results of a study focused on the metal (Cd, Co, Cr, Cu, Ni, Pb, Sb, U and Zn) distribution in soils and uptake and accumulation by earthworms Nicodrilus caliginosus (Savigny) from urban, peri-urban, green-urban and non-urban zones of Siena municipality (central Italy). The main goal was to define the influence of soil properties and metal soil contents on the uptake of these contaminants by earthworms. Data indicated that Cd, Cu, Pb, Sb and Zn soil contents increased in the following order: non-urban < green-urban < peri-urban < urban soils, suggesting that vehicular traffic affects the distribution of these metals. Pb and Sb were the main soil contaminants and their highest enrichments were found in urban sites where stop-and-go traffic occurs. Concentrations of these traffic-related metals in earthworms showed a distribution pattern similar to that in soil, suggesting that soil contamination influenced the uptake of Cd, Cu, Pb, Sb and Zn by N. caliginosus. There were significant positive correlations between Cd, Pb and Sb earthworm concentrations and their soil contents. The lack of correlation for Cu and Zn could be due to the physiological regulation of these elements by earthworms. Statistical analysis pointed out that the uptake and accumulation of Cd, Cu, Pb, Sb and Zn by earthworms were affected by some soil physicochemical properties such as the organic carbon and carbonate contents that are able to rule the bioavailability of metals in soils.
Article
Nine toxicity tests were conducted using a procedure based on the OECD (1984) artificial soil earthworm toxicity test. For each test, Eisenia fetida were exposed to zinc in a range of artificial soils with differing pH and/or organic matter (OM) content. Earthworm survival and cocoon production, and the concentrations of zinc in two fractions (nitric acid extractable, water extractable) and the exposed earthworms were measured. The proportion of total zinc that was soluble was greater in soil with low pH and low OM content. Zinc burdens were greatest in worms maintained in the most contaminated soils. However, the slopes of the relationships between earthworm zinc concentrations and zinc concentrations in soils (total and soluble) were less than one indicating probable regulation of net assimilation of this essential element by Eisenia fetida. Toxic effects of zinc on Eisenia fetida as measured by reductions in survival and cocoon production were related more closely to soluble than total metal concentrations in soil. In a previous series of tests, zinc toxicity for Eisenia fetida was found to be at least ten times greater in OECD artificial soil when compared to contaminated soils collected from a polluted field site (Spurgeon & Hopkin, 1995). It was concluded that this was due to the greater bioavailability of the metals in the OECD soil. The results of the present paper support this hypothesis.
Article
This study aimed at assessing the bioavailability and toxicity of lead to Eisenia andrei in shooting range soils representing different land uses (forest, grassland, bullet plot). Soils contained 47-2398 mg Pb/kg dry weight (dw), but also had different pH-CaCl2 (3.2-6.8) and organic matter contents (3.8-13%). Therefore artificial soils with different pH and organic matter contents and two natural soils were included as control soils. Earthworms were exposed for 28 days and toxicity and uptake of Pb were related to total, water and 0.01 M CaCl2 extractable and porewater Pb concentrations as well as to soil characteristics. Pb uptake in the earthworms linearly increased with increasing soil concentrations. At >2000 mg Pb/kg dw and pH 3.3-3.5, high earthworm mortality with significant weight loss and complete inhibition of reproduction were recorded. At <1000 mg/kg dw, earthworm reproduction was more related to differences in pH and other soil characteristics than to Pb.
Article
Seventeen soil samples from acidic forest soils and near-neutral agricultural soils were used in an experiment to compare three methods of determining c.e.c. The methods tested are the sum of cations displaced with 0.1 M BaCl2, and exchangeable Ba, after saturation with BaCl2 and replacement with either MgSO4 (compulsive exchange) or MgCl2. The results show that when Al, Mn and Fe are included with Ca, Mg, Na and K in the sum of cations, this method gives the same result as do the other methods. It is recommended that this simple one-step method be used in routine analysis of acidic soils, especially when non-agricultural lands are under investigation. (Authors' abstract)-C.N.
Article
Heavy metal concentrations in 6 terrestrial slug species (Deroceras reticulatum, D. caruanae, Arionater, A. hortensis, A. subfuscus and Milax budapestensis) inhabiting a disused Pb/Zn mine site were measured by atomic absorption spectrophotometry. Relationships between dry weight: metal content and dry weight: metal concentration, respectively, were investigated by regression analysis before and after log transformation. Interspecies, as well as inter-metal differences in metal accumulation were more effectively demonstrated by comparing metal content: dry body weight relationships, as opposed to metal concentration: dry body weight relationships. Regression analysis revealed differences in metal accumulation between the non-essential trace metals Pb/Cd and the metabolically essential trace metals Zn/Cu. Species differences in metal accumulation were more pronounced when their coefficients of functional regression were compared, the greatest differences being observed for species belonging to different genera. However, the presence of a high level of intrinsic variability in metal levels reduces the effectiveness and significance of the metal content: dry body weight expressions, and also detracts from the immediate prospect of using terrestrial slugs as biomonitors of environmental metal pollution.
Article
Glyphosate (GPS) and copper (Cu) are common pollutants in soils, and commonly co-exist. Due to the chemical structure of GPS, it can form complexes of heavy metals and interface their bioavailability in soil environment. In order to explore the interactions between GPS and Cu, subacute toxicity tests of Cu and GPS on soil invertebrate earthworms (Eisenia fetida) were conducted. The relative weight loss and whole-worm metal burdens increased significantly with the increasing exposure concentration of Cu, while the toxicity of GPS was insignificant. The joint toxicity data showed that the relative weight loss and the uptake of Cu, as well as the superoxide dismutase, catalase and malondialdehyde activities, were significantly alleviated in the present of GPS, which indicated that GPS could reduce the toxicity and bioavailability of Cu in the soil because of its strong chelating effects.