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Phytomanagement of radionuclides and heavy metals in mangrove sediments of Pattani Bay, Thailand using Avicennia marina and Pluchea indica
Abstract
This study determines uptake and accumulation of radionuclides and heavy metals by Pluchea indica and Avicennia marina and evaluates phytoremediation potential via greenhouse and field experiments. P. indica and A. marina are considered excluders for40K and262Ra, and Pb since roots accumulated them in higher quantities compared to other plant parts, and the bioconcentration factor (BCF) and transfer factor (TF) values for Pb, and40K and262Ra were >1, respectively. Absorbed dose rate in air (D) showed significant values in sediments, which were generally over the maximum recommended value of 55nGyh-1. Phytostabilization of radionuclides and heavy metals may serve as an appropriate strategy for mangrove-polluted areas. D values in sediments were considered sufficiently high to recommend long-term monitoring. Radionuclide activities may increase in the food chain via uptake and accumulation of edible plants, ultimately resulting in harm to human health.
... The pollution extent could be classified according to the scale proposed by Muller (1981) who distinguished seven classes of contamination (Table 1). It is defined as the ratio of concentration of heavy metal (Kaewtubtim et al., 2018) inside biological tissues to that of the sediment. It was determined using the following equation. ...
... MacFarlane et al. (2003) recorded that Cu and Zn showed some mobility in the plant, being accumulated in leaf tissue in levels of approximately 10% root levels. It is clear that A. marina and H. stipulacea absorbed Pb from the sediment and restricted it in roots, this result is in agreement with results of Kaewtubtim et al. (2018) for A. marina in greenhouse and field experiments. Thus the two plants can be used in phytostablization of Pb form contaminated sediments without hazards on grazing animals. ...
... Heavy metals content (μgg -1 ) in A. marina and H. stipulacea plants from Red Sea CoastMeans in the same Raw with the same litter not significantly differed at P<0.05All these studies recorded low concentration of Pb in A. marina plant parts than the present study. The present results recorded high concentration of Cu in the vegetative parts than the subterranean parts of A. marina and Cu and Zn in H. stipulacea, similar results were recorded byDar et al. (2017) for A. marina in different sites along Red Sea coast,Essa (2016) for H. stipulacea in Safaga, Red Sea Coast andKaewtubtim et al. (2018) for A. marina in in greenhouse and field experiment. Metal concentrations in plant tissues such as Cu and Zn are triggered by metabolic requirements ...
Increasing load of heavy metals and radionuclides in aquatic ecosystems leads to an imbalance state and threatens health of existing biota. Heavy metals (Fe, Mn, Zn, Cu and Pb) and gamma-ray activities produced by natural radionuclides 238 U, 232 Th and 40 K, were determined in un-vegetated and vegetated (mangrove and seagrasses) sediments as well as plants from Safaga area, Egyptian Red Sea Coast. Contamination levels were detected by Zn and Pb in vegetated sediments and Mn, Zn and Pb in un-vegetated sediments. The enrichment factor (EF) and geo-accumulation index (I geo) indicated presence of anthropogenic pollution. Vegetated and un-vegetated sediments contain activity of 238 U and 232 Th lower than permissible levels, while mangrove and un-vegetated sediments contaminated with 40 K radionuclides. Avicennia marina plant has high potential to accumulate high concentrations of Zn, Cu and Pb in its roots but low tendency to translocate them to the shoots. Halophyla stipulacea takes up low concentrations of the investigated heavy metals and translocate most of them to the shoots. A. marina and H. stipulacea plants showed low activity of radioisotopes 238 U and 232 Th but high of 40 K radioisotope with many folds more than the permissible limits. The current investigations showed that all hazard indices of natural radionuclides activity were lower than the permissible levels. The current results are one of the tools to determine the possibility of using A. marina and H. stipulacea plants as bioindicators for contamination with Zn, Cu, Pb and 40 K and recommended that A. marina plants is a good candidate for phytoremediation of Zn, Cu, Pb and 40 K in polluted marine ecosystems.
... The pollution extent could be classified according to the scale proposed by Muller (1981) who distinguished seven classes of contamination (Table 1). It is defined as the ratio of concentration of heavy metal (Kaewtubtim et al., 2018) inside biological tissues to that of the sediment. It was determined using the following equation. ...
... MacFarlane et al. (2003) recorded that Cu and Zn showed some mobility in the plant, being accumulated in leaf tissue in levels of approximately 10% root levels. It is clear that A. marina and H. stipulacea absorbed Pb from the sediment and restricted it in roots, this result is in agreement with results of Kaewtubtim et al. (2018) for A. marina in greenhouse and field experiments. Thus the two plants can be used in phytostablization of Pb form contaminated sediments without hazards on grazing animals. ...
... Heavy metals content (μgg -1 ) in A. marina and H. stipulacea plants from Red Sea CoastMeans in the same Raw with the same litter not significantly differed at P<0.05All these studies recorded low concentration of Pb in A. marina plant parts than the present study. The present results recorded high concentration of Cu in the vegetative parts than the subterranean parts of A. marina and Cu and Zn in H. stipulacea, similar results were recorded byDar et al. (2017) for A. marina in different sites along Red Sea coast,Essa (2016) for H. stipulacea in Safaga, Red Sea Coast andKaewtubtim et al. (2018) for A. marina in in greenhouse and field experiment. Metal concentrations in plant tissues such as Cu and Zn are triggered by metabolic requirements ...
... Therefore, remedial measures are required to mitigate potential impacts of these hazardous trace elements (Mondal et al. 2018). Mangroves are known to play an effective role in alleviating metal pollutants through accumulating them in their own tissues (Zhou et al. 2010;Usman et al. 2013;Nath et al. 2014b) and have been reported to exhibit significant phytoremediation potential for certain heavy metals (Einollahipeer et al. 2013;Kaewtubtim et al. 2016;Kaewtubtim et al. 2018). ...
... In Thailand, the bioconcentration factor (BCF) values for the roots of A. marina were 8.1 for Zn, 1.5 for Cu, 10.1 for Pb, and 10.6 for Cd, while for the leaves, the respective values were 4.7, 1.7, 4.1, and 12.2 (Kaewtubtim et al. 2016). Furthermore, A. marina was considered a heavy metal excluder species, since roots accumulated certain heavy metals in higher quantities than other plant parts (Kaewtubtim et al. 2018). Despite efforts undertaken to evaluate pollution levels in the Persian Gulf, continuous monitoring and additional research on accumulation of pollutants in local marine flora are essential for identifying gaps in our knowledge that could be used for better management of these sensitive ecosystems. ...
Trace elements (Zn, Cu, Pb, and Cd) in root and leaf tissues of the gray mangrove (Avicennia marina) and in corresponding sediment samples were studied. Samples were taken from the inflow/outflow points in two distinct habitats, i.e., the Hara Protected Area and the Azini Bay, of Hormozgan Province in south Iran. Heavy metal concentrations (μg g-1 of dry weight) in the sediments of the Hara Protected Area ranged from 16.0 to 68.0 for Pb, 15.0 to 52.0 for Zn, 9.0 to 27.0 for Cu, and 1.0 to 3.3 for Cd. In the Azini Bay, these concentrations ranged from 7.1 to 27.5 for Pb, 17.1 to 55.9 for Zn, 12.1 to 37.9 for Cu, and 0.2 to 2.3 for Cd. The accumulation trend of heavy metal concentrations in the roots of A. marina was in the order Pb (16.1) > Zn (15.8) > Cu (9.3) > Cd (1.3) μg g-1 of dry weight in the Hara Protected Area and in the order Zn (13.7) > Cu (9.4) > Pb (5.5) > Cd (0.6) μg g-1 of dry weight in the Azini Bay. The value of translocation factor (TLF) was smaller than 1 in both regions. It was estimated from 0.44 to 0.62 in the Hara Protected Area and from 0.51 to 1.01 in the Azini Bay. The enrichment coefficient for root (ECR) varied from 0.32 to 0.93 in the Hara Protected Area and from 0.32 to 0.51 in the Azini Bay. The ratio of heavy metals in leaves/sediments (ECL) also varied from 0.01 to 0.67 in the Hara Protected Area and from 0.01 to 0.47 in the Azini Bay. The enrichment coefficient for leaf (ECL) was always lower than ECR in both regions. Based on the above findings, A. marina can be regarded as an excluder for the heavy metals examined in this study, given its low efficiency in translocating and accumulating the heavy metals in the shoots. Apart from serving as a baseline for the study area, findings could be useful for mitigating heavy metal contamination in these sensitive ecosystems through possible phytomanagement using gray mangrove.
... This issue has garnered considerable focus over the last decade. 4,5 In regions adjacent a tailings pond in southeastern China, the U content in agricultural land can reach up to 6.35 mg/kg. Additionally, the average concentrations of other heavy metals, including Cd, Cr, Pb, Cu, and Zn, exceed national soil background values. ...
BACKGROUND
Soil in uranium mining areas is contaminated by uranium and associated heavy metals, posing a significant threat to human health and ecological security. Chelating agent assisted phytoremediation is a cost‐effective and ecologically friendly remediation approach for uranium and associated heavy metals contaminated soil. In this work, a novel slow‐release composite chelating agent (SRCMC‐g‐CMCD‐EDTA/AC) was fabricated using carboxymethyl chitosan‐graft‐carboxymethyl‐β‐cyclodextrin (CMC‐g‐CMCD) as a slow‐release carrier and EDTA/ammonium citrate (AC) as a composite chelating agent through the spray drying method, which was used for phytoremediation of soil co‐contaminated with uranium and chromium.
RESULTS
CMC‐g‐CMCD exhibited superior slow‐release performance for both EDTA and AC in comparison with CMC and CMCD. When applied to soil contaminated with uranium (U) and chromium (Cr), SRCMC‐g‐CMCD‐EDTA/AC effectively regulated the release of U and Cr. Sunflowers (Helianthus annuus L.) grown in treated soil showed a significant increase in U and Cr uptake by 70.55% and 35.55%, respectively, and reduced leaching losses by 34.88% and 37.42%.
CONCLUSION
SRCMC‐g‐CMCD‐EDTA/AC not only assists in the phytoremediation of soil co‐contaminated with U and Cr but also reduces the risk of leaching into groundwater during the soil phytoremediation process. SRCMC‐g‐CMCD‐EDTA/AC‐assisted phytoremediation technology was an effective and environmentally friendly remediation means for the removal of U and heavy metals from contaminated soils in uranium mining areas. © 2024 Society of Chemical Industry (SCI).
... Nevertheless, there has been limited research on the accumulation of radionuclides in mangrove plants. Hence, the assessment of the transfer factor of radionuclides from soil to plants is crucial for conducting health risk evaluations and phyto-stabilization investigations (Kaewtubtim et al., 2018;Vandenhove et al., 2009). The Sundarban mangrove forest is located in the southwestern region of Bangladesh, where the Ganga-Brahmaputra-Meghna river system merges. ...
The natural radioactivity (226 Ra, 232 Th, and 40 K) levels of some medicinal plants and soils in the Sundarban mangrove ecosystem in Bangladesh were assessed for the first time using gamma-ray spectrometry. Depth-wise activity concentration variations for most of the soil cores indicate an increase in radiological contamination in recent years. Although some radiological hazard parameters for soils are higher than the global average values, excess lifetime cancer risk values are below the acceptable limit. The activity concentrations of 226 Ra, 232 Th, and 40 K in the studied medicinal plant leaves varies from 9.03 ± 3.01 to 66.9 ± 8.2 Bq kg − 1 , 25.3 ± 5.0 to 155 ± 16 Bq kg − 1 , and 68.1 ± 8.3 to 139 ± 12 Bq kg − 1 , respectively. For the studied medicinal plants, the soil-to-plant transfer factors of 226 Ra, 232 Th, and 40 K ranged from 0.20 to 1.36, 0.27 to 2.08, and 0.036 to 0.108, respectively. This study indicates that people's consumption of medicinal plants is radiologically safe. The present study assessed radiological risks to develop new strategies to save the sensitive Sundarban ecosystem.
... Bioconcentration factor (BCF) and transfer factor (TF) were used to evaluate the accumulation capacity of plant heavy metals (Kaewtubtim et al. 2018;Madejón et al. 2018), which respectively reflect the ability of plant to absorb heavy metals from soil and the ability of plant to transfer heavy metals from root to ground after absorption. The calculation formula was as follows: ...
Bioavailable heavy metal and their efficient phytoremediation in mining areas have major implications for environmental and human health. In this study, we investigated 12 dominant plants in a typical Mn ore area of Zunyi, Guizhou Province, China, to determine the heavy metal contents, morphologies, and environmental factors affecting Mn, Cd, Pb, Cu, Zn, and Cr in the plant parts and rhizosphere soil. The bioavailabilities and degrees of metals were evaluated using the ratios of the secondary to primary phase distributions and potential ecological risk indices. Principal component analysis, cluster analysis, positive matrix factorisation modelling, and redundancy analysis were used to trace the origins and correlations among the metals. The results indicate that the bioavailabilities were the highest for Mn and Cd in the study area, and all of the target heavy metals had bioavailabilities above the moderate ecological harm level. Statistical modelling indicates that there are four main pollution sources: mining, smelting, processing operations, and atmospheric deposition. The dominant plants had high heavy metal enrichments, bioconcentration factors, and translocation factors for Mn, Cu, Cr, Cd, and Zn. The redundancy analysis indicates that soil total N, total P, and pH affect metal absorption and distributions in Compositae and non-Compositae plants in low-N, low-P, and slightly alkaline mining environments. This study provides a feasible basis for the screening of heavy metal enrichment plants and the improvement of remediation technology in manganese ore area under the extreme environment of poor nutrition.
... S. portulacastrum also fixed Mn and Cr but with lower performances. In another study (Kaewtubtim et al. 2018), the authors analyzed the metal bioaccumulation potential of Avicennia marina (tree) and Pluchea indica (shrub) in the field and in the greenhouse. The amounts of Mn, Ni, and Cr taken together accumulated in six months were similar to those of our experiment (BCF values were variable but not different on average than ours). ...
... The use of multiple plant species, particularly value-added, may prove helpful in phytomanagement of contaminated sites, mainly those contaminated with organic pollutants (Ma et al. 2013). Phytomanagement, as supported by many scientific research papers, is emerging as a new paradigm all over the world with its benefit in sustainable site management and economic return (Cundy et al. 2016;Ciadamidaro et al. 2017;Martinez-Oró et al. 2017;Kaewtubtim et al. 2018). The word "phytomanagement" is used in the context of remediation of contaminated sites as a new way to regulate ecosystem services to a greater end (Table 10.3). ...
... Pluchea indica (P. indica) is a shrub that grows upto 1 to 2 meters in height and is known for its traditional uses and diverse bioactivities coupled with anti-cancer, insecticidal, anti-inflammatory, anti-microbial and antioxidant properties [21,24]. Researchers have conducted a chemical investigation of this plant and identified several phytoconstituents comprising quinic acids, sesquiterpenes, sterols, flavonoids, lignans, and thiophenes, which could attenuate the production of crystal stones. ...
The focus of this research was to investigate the impact of combining curcumin-loaded gold nanoparticles (Au NPs) with P. indica root extracts on kidney stones formed in male Wistar rats. Besides, kidney stones were induced in male Wistar rats through the oral supplementation of 2% ethylene glycol mixed with drinking water. To evaluate the impact of P. indica-curcumin-Au NPs on kidney stones, the rats were given a dose of 150 mg/kg P. indica root extract, 100 mg/kg curcumin, and 100 ppm of gold nanoparticles via administration. Following the treatment, the Wistar rat’s kidney tissues were collected and analysed for further research. Curcumin is a primary active ingredient in turmeric that has shown significant biological, pharmacological and diverse effects, such as anti-inflammatory, antifibrotic, and antioxidant properties. Additionally, P. indica root extract has been shown to reduce the formation of oxalate stones in the kidneys. The presence of various phenolic compounds in P. indica such as flavonoids, quinic acids, thiophenes, terpenes, and sterols, are more likely to generate Au NPs. Subsequent addition of curcumin with P. indica root extract accelerates the formation of a complex with Au NPs which was confirmed by X-ray diffraction, UV- visible spectroscopy, Dynamic light scattering and Transmission electron microscopy results. The use of P. indica-curcumin-Au NPs relieved the oxidative stress response in the rat model by decreasing MDA content and raising GSH, CAT, GR, GPx, and SOD levels. Moreover, the combination efficiently inhibited the expression of IL-6, -SMA, collagen I, and MCP1 and protected kidney tissues from deterioration.
Graphical Abstract
... Caffeoylquinic acids, flavonol aglycones, and terpenoids in the leaves of P. indica play a vital role as antioxidants and medicinal compounds Srimoon & Ngiewthaisong, 2015;Vongsak et al., 2018). Moreover, P. indica has demonstrated its suitability as a good candidate for the phytoremediation of copper (Cu; Soraya et al., 2019), chromium (Cr;Sampanpanish et al., 2006), arsenic (As;Visoottiviseth et al., 2002), and mixed compositions of heavy metals (Kaewtubtim et al., 2016(Kaewtubtim et al., , 2018. However, high metal contamination is the major concern that arises with using the dried leaves of P. indica as herbal tea. ...
Indian camphorweed (Pluchea indica (L.) Less.) is used as herbal tea due to the presence of volatile aromatic oils and several phytochemical compounds. The aim of this study was to assess the impact of copper (Cu) contamination on the physiology and morphology of P. indica, and the health risks associated with its consumption as tea. The cuttings of P. indica were subjected to 0 mM (control), 5 mM (low Cu), and 20 mM (excess Cu) of CuSO4 treatments for 1, 2, and 4 weeks. Thereafter, Cu contamination as well as physiological and morphological parameters were assessed. Cu accumulation was higher in the root tissues of plants (25.8 folds higher as compared to the leaves) grown under 20 mM CuSO4 for 4 weeks. This increased Cu accumulation resulted in the inhibition of root length, root fresh weight, and root dry weight. Cu concentration was found maximum (1.36 μg g⁻¹ DW) in the leaf tissues under 20 mM Cu exposure for 4 weeks, with the highest target hazard quotient (THQ = 1.85), whereas Cu was not detected in control. Under exposure to 20 mM Cu treatment for 4 weeks, leaf greenness, maximum quantum yield of photosystem II, and photon yield of photosystem II diminished by 21.4%, 16.1%, and 22.4%, respectively, as compared to the control. Leaf temperature was increased by 2.5 °C, and the crop stress index (CSI) exceeded 0.6 when exposed to 20 mM Cu treatment for 2 and 4 weeks; however, the control had a CSI below 0.5. This led to a reduced transpiration rate and stomatal conductance. In addition, the net photosynthetic rate was also found sensitive to Cu treatment, which resulted in decreased shoot and root growth. Based on the key results, it can be suggested that P. indica herbal tea derived from the foliage of plants grown under a 5 mM Cu level (0.75 μg g⁻¹ DW) with a target hazard quotient below one aligns with the recommended dietary intake of Cu in leafy vegetables. The study recommends choosing cuttings from plants with a small canopy as plant material in the greenhouse microclimates to validate the growth performance in the Cu-contaminated soil and simulate the natural shrub architecture and life cycle.
... Plants with high BCF and TF values have high amounts of metal ions in the aerial tissues. Pluchea indica is reported to have a high level of Cr accumulation in leaves and is thus considered a good phytoremediator (Kaewtubtim et al., 2018). The BCF value of Azolla caroliniana is 11 (Pandey, 2012), which makes it a good phytoremediator compared to Amaranthus dubius, which has a lower BCF value than 2 and a TF value of 1.1 (Mellem et al., 2012). ...
Chromium (Cr) is a naturally occurring, carcinogenic heavy metal that has become a pressing concern in recent decadesfor environmentalists. Due to high anthropogenic activities, the concentration of Cr has crossed the environmental threshold levels and consequently contaminated soil and water. The high solubility of Cr ions in the groundwater results in its high uptake by the plants leading to phytotoxicity and yield loss. The dearth of efficient and cost-effective treatment methods has resulted in massive chromium pollution. However, some phytoaccumulators capable of accumulating Cr in high amounts in their shoots and then performing their metabolic activity typically have bdseen identified. Chromium bioremediation using phytoaccumulators is very contemplative due to its eco-friendly and cost-effective outcome. These accumulators possess several mechanisms, such as biosorption, reduction, efflux, or bioaccumulation, naturally or acquired to counter the toxicity of Chromium. This review focuses on the detoxification mechanism of Cr by the phytoaccumulator species, theirresponses against Cr toxicity, and the scope for their application in bioremediation. Besides, Cr bioavailability, uptake, distribution, impairment of redox homeostasis, oxidative stress, and phytotoxicity imposed on the plants are also summarized. Further, the knowledge gap and prospects are also discussed to fill these gaps and overcome the problem associated with the real-time applicability of phytoaccumulator-basedbioremediation.
... Ghasemi et al. [96] reported the phytomanagement of PTMs in mangrove sediments of Hormozgan, Iran, using A. marina. In addition, using greenhouse and field tests, Kaewtubtim et al. [97] assessed the uptake and accumulation of PTMs by Pluchea indica and A. marina and concluded that the mangrove had the potential for phytoremediation. ...
Simple Summary
This study evaluated the capacity for the phytoremediation of mangrove Avicennia, sampled from the Klang mangrove ecosystem, and analysed the ecological-health concerns of potentially toxic metals in the surface sediments. All of the hazard index values of the surface sediments for Cu, Ni, Pb, and Zn, based on a combination of three pathways, indicated 1.00, suggesting that the four metals are not carcinogenic. The lamina has more potential as a phytoremediator of vital Cu, Zn, and Fe, according to the bio-concentration factor values. As a phytoremediator of non-essential Pb and Ni, midrib plus petiole has greater potential. The data presented in this study can be used to monitor and provide ecological-health hazards of potentially toxic metals in the Klang mangrove ecosystem to lessen the threats to the ecosystem. Using the current findings to manage the Klang mangrove ecosystem, a water-energy-food framework can be proposed.
Abstract
This study aimed to evaluate the ecological-health risks of potentially toxic metals in the surface sediments on the Klang mangrove ecosystem and assessed the phytoremediation potential of Avicennia officinalis collected from the area. The results showed that the concentrations (mg/kg dry weight) of Cu, Ni, Pb and Zn in the surface sediments ranged between 5.30–63.8, 14.2–32.7, 30.3–62.3, and 46.4–269, respectively. The ecological risk values of the surface sediments indicated that Ni, Pb and Zn were all classified as ‘low potential ecological risk’, while the Cu ecological risk ranged between ‘low potential ecological risk’ and ‘considerable potential ecological risk’. For the health risks on the sediments, all of the values of hazard index for Cu, Ni, Pb and Zn, based on a combination of three pathways, indicated < 1.00, showing that the four metals are non-carcinogenic. Based on the bioconcentration factor values, it can be concluded that the lamina has better potential as a phytoremediator of essential Cu, Zn and Fe. In contrast, midrib plus petiole has better potential as a phytoremediator of non-essential Pb and Ni. To mitigate the threats to the Klang mangrove ecosystem, the information offered in the present study can be employed in the monitoring and provision of the ecological-health risks of potentially toxic metals in the Klang mangrove ecosystem. Hence, the present findings can be employed for developing a water-energy-food framework for managing the Klang mangrove ecosystem.
... Contudo, Yu et al. Neste contexto, diversos pesquisadores no mundo utilizaram as ferramentas da biogeoquímica na avaliação de impactos ambientais da poluição por metais-traço de sedimentos e das plantas do manguezal, a exemplo dos trabalhos que foram realizados por Defew et al. (2005), Leão et al. (2008), Garcia et al. (2008), Silva (2011), Gonçalves et al. (2012, Birch et al. (2015), Chowdhury et al. (2017), Kaewtubtim et al. (2018), Almahasheer et al. (2019), Barros et al. (2021) Camamu, pôde ser comparada aos níveis destes metais nos sedimentos do manguezal de Santo Amaro, na Bahia, sob pressão da poluição metais-traço associados aos uso da terra, as atividades urbano-industriais e a mineração de chumbo, de acordo com Queiroz (1992). ...
Os bosques de mangue constituem o patrimônio natural, os atrativos ao turismo e ofertam serviços ecossistêmicos para os usos da natureza no Litoral Sul da Bahia. Esta pesquisa teve como objetivo investigar aspectos geobotânicos (diagnose e biometria foliar) e os níveis dos metais-traço (Cu, Zn, Cd, Pb) nos sedimentos e nas folhas de plantas de mangue da APA Tinharé-Boipeba, Cairu, Baixo Sul da Bahia, Brasil. Considerou-se os níveis de metais-traço nas folhas das espécies Avicennia schaueriana e Laguncularia racemosa (10 pontos) e sedimentos (40 pontos), por Espectrometria de Absorção Atômica com Chama (FAAS), e das análises das variáveis ecológicas-geobotânicas. Os níveis dos metais-traço nas folhas das espécies de mangue foram considerados não tóxicos (Zn > Cu > Pb > Cd) e os níveis dos metais-traço nos sedimentos (Zn > Pb > Cd) sugeriram que os bosques de mangue da APA não poderiam ser considerados poluídos. Os valores do FC (< 1,0) apontaram que os metais não estariam biodisponíveis e que o acúmulo destes nas folhas não correspondeu aos níveis nos sedimentos. A análise multivariada indicou que as variações na área e na integridade foliar podem representar uma resposta a um estressor distinto dos investigados e discriminou os metais segundo a mobilidade geoquímica. Recomenda-se a realização de novas pesquisas de biogeoquímica centradas na avaliação de impactos e na conservação.
... A preocupação com os impactos ambientais negativos da poluição dos sedimentos do manguezal por metais-traços, decorrentes de atividades urbano-industriais, foram reportados em P á g i n a | 217 diversos estudos, a exemplo daqueles realizados na Austrália, Brasil, China, Colômbia, Guiana Francesa, Equador, Índia, Panamá, Porto Rico, Tailândia (THOMAS;FERNANDEZ, 1997;SAENGER;MCCONCHIE et al., 2004;DEFEW et al., 2005;MACHADO et al., 2002;MACHADO et al., 2005;MARCHAND et al., 2006;LEÃO et al., 2008;ESPINOSA et al., 2011;GONÇALVES, et al. 2012;QIU et al., 2011;MEJÍAS et al., 2013;FERNÁNDEZ-CADENA et al., 2014;CHOWDHURY et al., 2017;KAEWTUBTIM et al., 2018;SOUZA FILHO, 2021). Oliveira et al.(2009) (SILVA et al., 2009;ALENCAR, 2011;PAIXÃO et al., 2016;ELLIFF;KIKUCHI, 2017;GONÇALVES et al., 2020;PELLEGRINI et al., 2020;VILAR et al., 2021;GONÇALVES et al., 2022a;GONÇALVES et al., 2022b) Em relação ao contexto climático, a APA Tinharé-Boipeba, no Baixo Sul da Bahia, situase sob a zona de clima quente e úmido, tropical costeiro, entre as faixas Aw e Af, com base na classificação de Köppen (1948). ...
O manguezal oferece serviços ecossistêmicos basilares para a reprodução social da vida, dos modos de vida tradicionais e da biodiversidade nas áreas costeiras do Planeta. Esta pesquisa almejou investigar os níveis de metais-traço nas folhas da Laguncularia racemosa e nos sedimentos dos bosques de mangue da Área de Proteção Ambiental (APA) Tinharé-Boipeba, Baixo Sul da Bahia, Brasil. Coletou-se folhas da L. racemosa em 10 pontos amostrais e sedimentos em 40 pontos amostrais para as análises laboratoriais de metais-traço por Espectrometria de Absorção Atômica com Chama (FAAS). Foram realizadas, igualmente, as análises laboratoriais das variáveis integridade foliar e biometria foliar. Os níveis dos metais traço nas folhas da L. racemosa foram normais e não tóxicos (Zn> Cu > Pb > Cd) e os teores de metais traço nos sedimentos (Zn> Pb > Cu) desta APA não caracterizam uma área poluída, porém deve-se incentivar o monitoramento dos metais-traço nos sediementos, biota e nas águas. A análise multivariada sugeriu que a variação da área foliar poderia ser atribuída aos níveis do Cu e Zn, além de fatores geoecológicos distintos dos investigados.
... Mangrove ecosystems are highly dynamic ecosystems, and their physicochemical, hydrological, sedimentological, and geomorphological conditions change rapidly as oceanic and continental drivers change in type and magnitude over time and space (Feller et al., 2010). Mangroves offer critical ecosystem services, such as maintaining biodiversity, filtering pollutants, providing habitat to endangered species, biogeochemical cycling of nutrients, and carbon sequestration (Kaewtubtim et al., 2018;Li et al., 2017;Ray et al., 2021;Su et al., 2021;Zhu et al., 2021). Despite these socio-economic benefits, mangrove ecosystems are threatened by anthropogenic activities. ...
Mangroves are highly dynamic ecosystems that offer important services such as maintaining biodiversity, filtering pollutants, and providing habitats for fishes. We investigated the uptake and accumulation of nutrients and potentially toxic elements in mangrove plants and fish to better understand the role of mangrove restoration in maintaining mangrove biota quality. In mangrove plants, the average bioconcentration factors of nutrients and potentially toxic elements were in the order P > Pb > Mn > Mg > Se > Zn > Hg > Cu > Cd > As > Co > Cr > Ni > Fe > V > Sb, where only P (all plant species) and Pb (Sonneratia apetala Buchanan-Hamilton) had a BCF > 1.0 in mangrove plants. In general, Sonneratia spp. had better performances than Kandelia candel (Linn.) Druce, Aegiceras corniculatum (Linn.) Blanco and Acanthus ilicifolius L. Sp. in terms of nutrient uptake and toxic metal(loid)s accumulation, and the best uptake capacity was found in S. apetala. Fast growth and easy adaptation make S. apetala suitable for a restored mangrove ecosystem, but continual management is needed to prevent its suppression of mangrove species diversity. The concentration of As, Cd, Hg, Cu, Cr and Pb in the mangrove sediment were 30–220% higher than the Chinese National Standard of Marine Sediment Quality Class I limits, suggesting that the sediments were unsuitable for aquaculture and nature reserves. Although a higher toxic metal(loid)s concentration in the sediment was found, the target hazard quotient (THQ) of this toxic metal(loid)s in 5 mangrove habitat fishes was <1.0, except THQ of Pb in Boleophthalmus pectinirostris Linnaeus was 1.17, and THQ of Cr in Bostrychus sinensis Lacépède was 1.12. The low THQ (less than 1.0) of mangrove habitat fishes suggested that the restored mangrove system could alleviate the bioaccumulation of toxic metal(loid)s in mangrove fish.
... According to [7] BCF was calculated to determine the phytoremediation potential. According to [8] the BCF value is classified into 3, namely the value of BCF <1 is called an excluder, BCF = 1 is classified as an indicator plant and BCF>1 is an accumulator. The higher the BCF value, the plant is able to accumulate heavy metals higher than the accumulation of heavy metals in the soil. ...
The existence of number industries in Surabaya as the largest industrial cities in Indonesia have affects how much waste they produce and is wasted in the waters. Heavy metal Zn (zinc) is one of the ingredients in the waste. The aim of this study was to analyze the Zn content in the roots and leaves of Avicennia marina as well as sediments around it which did in triplicates from 3 stations in Wonorejo Mangrove. The method used in this study was descriptive method. Zn analysis was used the Atomic Absorption Spectophotometer (AAS) method. Water quality analysis included temperature, pH and salinity was carried out in the field. The results of the Zn analysis obtained the highest value based on the station, namely at station 1 and the lowest at station 2. Based on the samples taken, the highest Zn concentration was found in the sediment and the lowest was in the leaves. The results of the concentration of Zn in the roots, leaves and sediment at each station did not differ much. The calculated values for BCF and TF were less than 1. Analysis of the water quality of the three parameters was still in normal conditions for the growth of mangrove biota. From this research, A. marina is included in the type of mangrove that can absorb heavy metals at low concentrations. This is in accordance with the BCF and TF values obtained. Low heavy metal absorption, this type of mangrove is still classified as a phytoremediator.
... Many studies on sediment heavy metals (HMs) have been widely reported from the ASEAN-5 countries, including Malaysia [6][7][8][9][10], Thailand [11][12][13], Philippines [14], Vietnam [15,16], and Indonesia [17][18][19]. All the studies partly assessed the ecological risk (ER) of metals but not at all for the human health risk assessment (HHRA) of HMs. ...
Simple Summary
This study aimed to review and compile the concentrations of Cu, Pb, and Zn in the aquatic sediments of the ASEAN-5 countries published in the literature from 1981 to February 2021. The mean values of Cu, Pb, and Zn in aquatic sediments were found to be elevated and localized in high human activity sites in comparison to the earth’s upper continental crust and reference values. All reports (100%) showed the Zn ecological risk (ER) values were categorized as being between ‘low potential ER’ and ‘considerable potential ER’. Almost all Cu ER values (97.7%) showed similar ranges of the above two risk categories except for a few reports. Almost all reports (96%) showed Pb ER values categorized as between ‘low potential ER’ and ‘moderate potential ER’ except for a few reports. For the ingestion and dermal contact pathways for sediments, all non-carcinogenic risk (NCR) values for Cu, Pb, and Zn reflected no NCR. This provided evidence for the ASEAN-5 group of countries to be considered as being a new socio-economic corridor. Lastly, we claim that this study is currently the most up-to-date review on this topic in the literature.
Abstract
The ASEAN-5 countries (Malaysia, Indonesia, Thailand, Philippines, and Vietnam) of the Association of Southeast Asian Nations as a group is an ever-increasing major economy developmental hub in Asia besides having wealthy natural resources. However, heavy metal (HM) pollution in the region is of increasing environmental and public concern. This study aimed to review and compile the concentrations of Cu, Pb, and Zn in the aquatic sediments of the ASEAN-5 countries published in the literature from 1981 to February 2021. The mean values of Cu, Pb, and Zn in aquatic sediments were elevated and localized in high human activity sites and compared to the earth’s upper continental crust and reference values. Based on 176 reports from 113 publications, the ranges of concentrations (mg/kg dry weight) were 0.09–3080 for Cu, 0.37–4950 for Zn, and 0.07–2666 for Pb. The ecological risk (ER) values ranged from 0.02–1077 for Cu, 0.01–95.2 for Zn, and 0.02–784 for Pb. All reports (100%) showed the Zn ER values were categorized as being between ‘low potential ecological risk’ and ‘considerable potential ecological risk’. Almost all Cu ER values (97.7%) also showed similar ranges of the above two risk categories except for a few reports. The highest Cu level (3080 mg/kg dry weight) was reported from a mine-tailing spill in Marinduque Island of the Philippines with ‘very high ecological risk’. In addition, drainage sediments in the western part of Peninsular Malaysia were categorized as Cu ’high potential ecological risk’. Almost all reports (96%) showed Pb ER values categorized as between ‘low potential ecological risk’ and ‘moderate potential ecological risk’ except for a few reports. Six reports showed Pb ER values of ‘considerable potential ecological risk’, while one report from Semarang (Indonesia) showed Pb ER of ‘very high ecological risk’ (Pb level of 2666 mg/kg dry weight). For the ingestion and dermal contact pathways for sediments from the ASEAN-5 countries, all non-carcinogenic risk (NCR) values (HI values 1.0) for Cu, Pb, and Zn reflected no NCR. The ER and human health risk assessment of Cu, Pb, and Zn were compared in an integrative and accurate manner after we reassessed the HM data mentioned in the literature. The synthesis carried out in this review provided the basis for us to consider Cu, Pb, and Zn as being of localized elevated levels. This provided evidence for the ASEAN-5 group of countries to be considered as being a new socio-economic corridor. Beyond any reasonable doubt, an ever-increasing anthropogenic input of HMs is to be expected to a certain degree. We believe that this paper provides the most fundamental useful baseline data for the future management and sustainable development of the aquatic ecosystems in the region. Lastly, we claim that this review is currently the most up-to-date review on this topic in the literature.
... m and is longlived (Yang et al., 2020). Many fast-growing plant species are suitable for phytoremediation, including several shrubs and trees that accumulate low levels of heavy metals in their tissues, as their high biomass production serves to compensate (Hauptvog et al., 2020;Kaewtubtim et al., 2018). Few studies have addressed the phytoremediation potential of P. amaryllifolius in heavy metal-contaminated water. ...
The potential of two aquatic plants, e.g., Typha angustifolia and Acorus calamus, and a terrestrial plant, e.g., Pandanus amaryllifolius, was evaluated in hydroponic experiments for rhizofiltration of cadmium (Cd) and zinc (Zn). Of the three species, T. angustifolia experienced a 100% survival rate and showed no symptoms of toxicity, with substantial values of dry biomass production (11.5–20.8 g) and Cd and Zn uptake (4941.1–14,109.4 mg plant⁻¹ and 14,039.3–59,360.8 mg plant⁻¹), respectively. The other tested plants showed lower performance; P. amaryllifolius experienced phytotoxicity effects in the 40 mg Zn L⁻¹ treatment. Based on our data, T. angustifolia is considered an excluder species for Cd and Zn as this species accumulated high Cd and Zn levels, primarily in roots, with bioconcentration factor (BCF) values > 100 and translocation factor (TF) values < 1 for all Cd and Zn treatments. All study plants exhibited lower heavy metal accumulation and uptake in most metal mixture treatments compared with Cd- or Zn-only treatments due to dilution effects. Percentage uptake of Cd by T. angustifolia increased with increasing Cd concentration (10.8–22.7%). Substantial percentage Zn uptake values were recorded at day 15 in the 40 mg L⁻¹ Zn treatment for A. calamus (89.1%). The study plants are rarely consumed on a daily basis; therefore, such levels of metal uptake should not adversely affect human health. Based on hydroponic system data, hazard quotient (HQ) values of Cd were > 1 for all treatments, indicating possible health risk from Cd via plant consumption. Although HQ values of Zn are also > 1, the maximum permissible level (MPL) (< 20,000 mg kg⁻¹) indicates that it occurs within acceptable levels. Only T. angustifolia is suggested as a suitable candidate plant in constructed wetlands and aquatic plant systems for removal of heavy metals.
Graphical abstract
... Other studies are carried out under experimental conditions, to evaluate the phytoremediation capacity of plants. For example, young plants of A. marina and Pluchea indica were collected from the Pattani Baymangrove forest (Thailand) and cultivated in mangrove sediment for three months inside a greenhouse and in the field [16]. They analyzed heavy metal (Cd, Cr, Pb, Cu, Mn, Ni, Zn) and radionuclide ( 226 Ra, 232 Th, and 40 K) concentrations. ...
Mangroves are coastal ecosystems that encompass diverse gradients of latitude (30∘N–37∘ S), tidal height (<1m to >4 m), geomorphology (oceanic islands for river systems), sedimentary environment (peat to alluvial), climate (hot temperate to arid and humid tropics) and availability of nutrients (oligotrophic to eutrophic). Mangrove ecosystems are also inhabited by large populations of aquatic and terrestrial animal and plant species, in addition to a wide variety of microorganisms. More specifically, mangroves support a unique biological diversity, providing vital habitats, spawning areas, nurseries, and nutrients for various animals, including several endangered reptiles (e.g. crocodiles, iguanas, and snakes), birds (herons, herons, pelicans, and eagles) and mammals (e.g. monkeys). Mangrove sediments house a variety of bacteria and fungi that assist in the cycling of nutrients and immobilization of contaminants. A complex community structure is distributed vertically through supratidal, intertidal, and subtidal zones and horizontally through the land-sea ecotone, which has allowed for the emergence of species specializations, especially in the intertidal zone. The structure provided by the forest essentially defines mangrove communities and ecosystems, creating stable habitats and conditions, modifying abiotic environments, and modulating ecosystem processes. Similar to terrestrial forests, mangrove forests are composed of a woody bole and a leafy canopy inhabited by ecological communities, not unlike those found in other tropical forests. However, unlike terrestrial plant species, the aerial root systems of mangroves also form an extensive aboveground structural framework, which dramatically increases the architectural complexity of these forests.
... Pluchea indica has been reported to have high salt tolerance ability at 273 mM NaCl with 3-4% growth reduction per every g L À1 NaCl (Glenn et al. 1998). Phytoremediating ability of P. indica has been investigated earlier for heavy metals (copper, zinc, arsenic, and chromium), but the phytodesalination ability has not been evaluated so far (Visoottiviseth et al. 2002;Kaewtubtim et al. 2018). Typha angustifolia (Narrow leaf cattail), a perennial aquatic plant, which grows up to 3 m in height, is found in mangrove forests (280 mM NaCl salinity), streams, riverbanks, and wetlands (Demirezen and Aksoy 2004;Kaewtubtim et al. 2016). ...
Sodium salt contamination in the fresh water due to industrial effluents, underground rock salts and inland aquaculture is a major concern needs to be remediated, and subsequently recycled as sustainable bioeconomic strategy. Treatment of saline wastewater requires efficient, cost-effective, rapid, and green technologies, so as to mitigate the negative impacts of salinity on agricultural land. Green technology of phytodesalination is proposed to reduce salinity in the wastewater using salt tolerant plant species. present study was designed with an aim to investigate the sodium (Na⁺) removal capacity of salt tolerant and high biomass producing macrophytes on synthetic saline wastewater. Sesuvium portulacastrum (sea purslane), Pluchea indica (Indian camphorweed), Typha angustifolia (narrow leaf cattail) and Heliconia psittacorum (heliconia) were collected, cultivated in the greenhouse, subsequently treated with 0 (control) and 217 mM NaCl (salt stress) for 4 weeks. Overall growth performance, physiological change and Na⁺ removal rate in root and leaf tissues of the candidate plant species were measured. Plants were able to maintain their growth and physiological abilities except for shoot height in T. angustifolia (reduced by 13.7%) and chlorophyll content in S. portulacastrum (reduced by 64%). Major accumulation of Na⁺ was recorded in the shoots of S. portulacastrum and P. indica (halophytic plant species) and the roots of T. angustifolia and H. psittacorum (glycophytic plant species). Since T. angustifolia and H. psittacorum have high plant biomass, they showed higher Na⁺ removal efficiency at 4.4% and 5.7%, respectively; whereas due to lower plant biomass, S. portulacastrum and P. indica resulted in the removal of only 0.6 and 0.8% Na⁺ from the batch, respectively. Based on the information from this investigation, the selected candidate plant species can further be studied in the constructed wetland together with the controlled environments including optimized flowrate, vertical or horizontal flow system, plant densities and Na-removal rate in relation to swamp habitat.
Novelty statement: T. angustifolia and H. psittacorum have high plant biomass, they showed higher Na⁺ removal efficiency at 4.4% and 5.7%, respectively; whereas due to lower plant biomass, S. portulacastrum and P. indica resulted in removal of only 0.6 and 0.8% Na⁺ from the batch. Based on the information from this investigation, the selected candidate plant species can further be studied in the constructed wetland together with the controlled environments including optimized flowrate, vertical or horizontal flow system, plant densities and Na-removal rate in relation to swamp habitat.
... Heavy metal content in plant parts varies on the basis of several accumulation mechanisms in vascular plants (Kováčik et al. 2017). Many plant species are known to concentrate heavy metals in roots during the natural processes of growth, while other plant parts, i.e., stems and leaves, manifest lower accumulation capability for most heavy metals (Kaewtubtim et al. 2018;Zhao and Duo 2015). Root cell walls act as the initial barrier to heavy metal translocation and inhibit heavy metal translocation from root apoplasts to the root xylem as a consequence heavy metals are distributed throughout the plant organs, e.g., stems and leaves, etc. (Lasat 2002;Liu et al. 2009). ...
Cadmium (Cd) and zinc (Zn) accumulation and uptake ability have been investigated in three ornamental monocot plants (Heliconia psittacorum x H. spathocircinata, Echinodorus cordifolius, and Pontederia cordata) grown in hydroponic systems. All study plants in the highest heavy metal treatments were found to be excluders for Cd and Zn with translocation factor values < 1 and bioconcentration factor (BCF) values > 100. The highest Cd and Zn accumulations were found in roots of E. cordifolius (4766.6 mg Zn kg⁻¹ and 6141.6 mg Cd kg⁻¹), followed by H. psittacorum x H. spathocircinata (4313.5 mg Zn kg⁻¹) and P. cordata (3673.3 mg Cd kg⁻¹), respectively, whereas shoots had lower performances. However, P. cordata had the lowest dry biomass production compared to the other two plant species in this study. As a result of dilution effects, heavy metal accumulation for all study plants was lower in the combined heavy metal treatments than in solely Cd and Zn only treatments. At the end of experiments, the highest uptakes of Cd and Zn were found in H. psittacorum x H. spathocircinata (62.1% Zn²⁺ from 10 mg Zn L⁻¹ solution) and E. cordifolius (27.3% Cd²⁺ from 2 mg Cd L⁻¹ solution). Low percentage metal uptakes were found in P. cordata; therefore, E. cordifolius and H. psittacorum x H. spathocircinata are clearly better suited for removing Cd and/or Zn from contaminated waters and hydroponic systems.
Graphical abstract
... Studies of environmental radioactivity levels have been of great importance and interest, mainly of natural radionuclides ( 238 U, 226 Ra) and their descendants ( 222 Rn, 210 Pb) present in the natural environment (Salles et al., 2019). Among the natural resources, the mangrove areas represent a remarkable heritage, since they have considered zones of high biological productivities being responsible for the productive dynamics of the tropical estuaries and adjacent areas (Kaewtubtim et al., 2018). ...
Currently, the increase in the environmental radioactivity levels was due to anthropic activities, such as the oil industries that produce around 2.5x104 to 2.25x105 tons of contaminated materials per year. Thus, the study aimed to determine the 210Pb concentrations in the estuarine region of the SUAPE industrial complex in the state of Pernambuco. The 210Pb concentrations were determined in soil, sediment, fish, and leaf samples, using ion exchange and gamma spectrometry methods. 210Pb concentrations in soils, sediments, fish, and mangrove leaves ranged from less than LD (Detection Limit) to 992.35 Bq.kg-1. The results showed that the area related to the preoperational situation found values above those estimated for regions considered natural, presenting anthropogenic interference.
... Therefore, P. dioscoridis has an exclusion strategy for Cu, Pb, Cd, and Zn to avoid excessive uptake. This result is in accordance with studies carried out on the same species (Eid and Shaltout, 2016;Klausen, 2017); and some other Pluchea species such as P. sagittalis (Rossato et al., 2012) and P. indica (Kaewtubtim et al., 2018). ...
The present study aims at developing a regression model for biomass estimation of Pluchea dioscoridis and investigating its ability to accumulate heavy metals from urbanized soils in order to be used as a potential bio-indicator of contaminated soils. In each of three residential sites, seven permanent quadrats (10 × 10 m) were selected for investigating the phenological behavior of P. dioscoridis, while an additional three quadrats were sampled for soil and plant analysis during March to November 2015. The flowering time of P. dioscoridis covers 7 months, with a peak in July. The above- and below-ground biomass attained their highest values in July. Concentrations of macro-nutrients in the shoot were significantly higher than in the root. However, concentrations of most heavy metals were significantly higher in the roots than in the shoots. The regression equations based on plant size index, as a predictor variable, was the best equation for different shoot compartments, while that based on plant diameter was the best equation for root biomass estimation. Based on the results of the bio-accumulation and translocation factors, P. dioscoridis can phytostabilize Cu, Pb, Cd, and Zn and can be used in a phytoextraction strategy for Cr. The significant positive correlations between Cd and Cr in soil with those in P. dioscoridis tissues suggest its potential use as a bioindicator and biomonitor for Cd and Cr pollution.
... S.K. Mandal, et al. Geoderma 354 (2019) 113891 were observed compared to those in sediments (Alongi et al., 2003;Kaewtubtim et al., 2018). In this current study, partitioning and transfer of As within sediment and mangrove plant was also very prominent. ...
... Phytomanagement-a new paradigm supported by several scientific research papers and based on the combination of phytoremediation and sustainable site management with economic return is emerging in research all over the world (Cundy et al., 2016;González-Alcaraz et al., 2013a;Martinez-Oró et al., 2017;Quintela-Sabarís et al., 2017;Ciadamidaro et al., 2017;Kaewtubtim et al., 2018). The term "phytomanagement" is used in the remediation of polluted sites as a new trend to manage ecosystem services, which has proved by published research papers shown in Table 1.4. ...
This introductory chapter summarizes the progress of the theoretical and practical aspects of phytoremediation, mainly focusing on phytoremediation actions. Several expansions in the theory and practices of phytoremediation have been achieved around the world mainly in developed countries during the past decade, though phytoremediation is still not popularized as a holistic approach with multiple benefits to remediate environmental pollution. Coordinating, we also attempt to link the gap between the theory and practice of phytoremediation through describing the term “phytomanagement.” The last section of this introductory chapter discusses the topic, sustainability issues of phytoremediation, in detail. In conclusion, economically valuable, unpalatable, and native plant-based phytoremediation is a promising idea to generate an income for phytocompanies, provide revenue to landowners, and for multiple benefits to the environment as well as to reduce the dangers faced by animals. In our opinion, our evidence-based suggestions and specific cases of phytoremediation around the world offer to put phytoremediation into action.
... A high production of aerial biomass is one of the main requirements for plants to be used for the decontamination of soils (Fern andez-Fuego et al., 2017;Kaewtubtim et al., 2018), and it has been demonstrated that the accumulation of photoassimilates in the aerial parts induces greater absorption of water (Rock, 2003), and thus greater absorption and translocation of contaminants from the soil solution to the roots and aerial parts. However, the plants have a limit for how much of such translocation they can achieve, and this limit is associated with the exhaustion of the transporters and internal complexers of the metals (Robinson et al., 1993). ...
Macrophytes are widely used in water treatment and have potential for remediation of flooded soils. Many techniques have been proposed to increase the phytoextraction of metals by macrophytes, however, the knowledge of periods of maximum absorption and translocation is essential and is a gap in the management of phytoremediation. To evaluate the absorption and translocation of Ba over time by Eleocharis acutangula, a greenhouse experiment was conducted and the dry matter production of plants, Ba content in the roots and aerial parts, mass of Ba accumulated in plants, translocation factors and removal coefficients of Ba, and Ba content in two layers of the soil (0.0–0.1 m and 0.1–0.2 m) were determined. The highest translocation rates were observed after 105 days of cultivation, when the plants reached a state of hyperaccumulation. The maximum accumulation of barium occurred in the aerial parts of the plants at 105 days and in the roots at both 120 and 180 days. The barium content was reduced up to 120 days, as a result of an increase in available barium content in the soil layer of 0.0–0.1 m up to 105 days and in the layer 0.10–0.20 m up to 120 days, favoring the intense accumulation of Ba during this period. After 120 days of cultivation, the accumulation in the roots maintained a high coefficient of removal of Ba from the soil to the plant. After 180 days the available barium in the soil was depleted due to this high rate of removal by the roots.
... Thus, suggesting that mangroves in the central Red Sea area are not under severe heavy metal pollution. Whereas, previous studies reported similar or higher metal concentrations in mangrove roots and shoots compared to those in soils (Alongi et al., 2003;MacFarlane et al., 2003MacFarlane et al., , 2007Kaewtubtim et al., 2018;Kulkarni et al., 2018), However, in our study, we found heavy metals concentrations in the soil to be significantly higher than the leaves, in particular, we found that some of the metals (i.e., Al, Cd, Fe, Mn, and V) were significantly higher along the 30-cm soil profile in Petro Rabigh, which could be due to industruial activities compared to the rest of locations. However, metal profiles in soils reveal significant fluctionations of metals inputs over time ( Figure 5). ...
Several studies have been carried out on heavy metal pollution in mangrove ecosystems. However, the role of mangroves in heavy metal remobilization is still relatively unknown. On one side, mangrove woody organs and soils sequester heavy metals for long time periods, but on the other hand, senescence of mangrove leaves may return these metals collected by roots to the upper layers of the soil. Here, we analyzed the concentration of chemical elements (Al, As, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sr, V, and Zn) as a function of age in mangrove leaves to understand heavy metals retention by the plant and to quantify the amounts shed with senescing leaves. In addition, we estimated metal concentrations and stocks in mangrove soils. Our results revealed that the concentration of most metals increased with leaf age, resulting in the remobilization of metals stored in soil, thereby returning metals to the upper layers of the soil during senescence of mangrove leaves. Only Cu was reabsorbed prior to shedding of leaves, a mechanism similar to that described for nutrients in mangroves globally. These results provide key data to understand mangroves role in the dynamics of heavy metals.
... Methods involving the use of plants (the so-called phytomanagement), which are safer and affect the environment to a lower degree, provide an alternative to physicochemical solutions aimed at eliminating TEs contamination from soil (Kaewtubtim, Meeinkuirt, Seepom, & Pichtel, 2018;Wan, Lei, Chen, Tan, & Yang, 2017). The most dynamically developing technologies include phytoremediation, which uses plants to clean soils, waters, and sediments. ...
Areas degraded by industrial activity demonstrate unfavourable chemical and physical conditions, including a high concentration of trace elements (TEs), which reduce the growth and development of appropriate plant cover. For the above reasons, in recent years the demand for the development of natural and effective technologies for removing particularly hazardous compounds such as TEs from the environment has been growing. Since aided phytostabilization is a relatively new technology, examination of new additions immobilizing TEs in combination with an appropriately selected species plan poses a challenge in environmental protection and engineering. The novelty of this study is in the assessment of the usefulness of previously not applied soil amendments in processes of TEs immobilization in contaminated soils. This study presents the results of a vegetation experiment using a mix of grasses and rarely‐used mineral soil amendments (halloysite, diatomite, dolomite) for aided phytostabilization of soil originating from an area affected by industrial activity and characterized by high TEs concentrations. Additionally, the degree of phytotoxicity of the examined soils was determined. The greatest above‐ground biomass was observed when diatomite, dolomite and halloysite were added to the soil. The concentrations of the analysed TEs in test plants were higher in roots than in the above‐ground parts. This indicates that mineral amendments affected soil properties promoting TEs precipitation and decreasing TEs bioavailability. The highest increase in soil pH was observed after the application of dolomite to the soil. The average contents of Pb, Ni, Cu and Cr in soil demonstrated the highest reduction after diatomite and halloysite application. The conducted research confirms the possibility of applying the examined soil additives to support phytostabilization of alkaline soil highly contaminated with TEs.
Radioactive pollution has become a cause of concern these days, especially with the growing industrial revolution. After traditional fossil fuels, nuclear power is important for fulfilling the growing needs of the world that leads to the release of radionuclides like uranium (235,238U), cesium (137Cs), neptunium (237Np), plutonium (239Pu), americium (241,243Am), curium (245Cm), strontium (90Sr), barium (133,140Ba), etc. that have long-term radiological and chemical toxicities, which make them hazardous even in small concentrations. They can also pollute the environment to varying degrees. They have long-term negative impacts on human health, including neurological abnormalities, birth deformities, infertility, and numerous types of cancer in different organs. Thus, there is an utmost need for the management and isolation of radioactive waste for the safety of the people and the future of the world. Phytoremediation is the process of removing contaminants from the contaminated site or making sure that the contaminants are less harmful after the process. Some of the phytoremediation approaches known to have mitigated radioactive pollutants include Phytoextraction, Phytodegradation, Phytostabilization, Phytovolatilization, Rhizofilteration, and/or a combination of these methods. A few of the plant species that have been reported for radionuclide phytoremediation include Triticum, Calotropis, Brassica, Helianthus, Catharanthus, Eichhornia, etc. Compared to existing remediation technologies, phytoremediation is more economical and environmentally beneficial. However, there are still some challenges that need to be addressed for more commercial applications of these methods such as the selection of suitable plant species, slower and long-term low performance, seasonal factors, applicability for contaminants deep in the soil, proper disposal, and management of plant due to potential chance of spread of more invasive plant species. Along with that, these approaches may face regulatory hurdles and public skepticism due to concerns about potential exposure to contaminants, negative effects on local communities and individuals near the contaminated sites, and long- term effects on the ecosystem and local biodiversity due to the risks associated with these remediation methods. Addressing these challenges will require ongoing study, technological developments, and a case-by-case assessment of phytoremediation’s feasibility for specific radioactive contaminants and environmental conditions. With ongoing research being continuously explored in this field, phytoremediation is projected to assume a growing function in the wider picture of environmental remediation, providing a sustainable and natural solution to the challenges faced by radioactive contaminants. The present study aims to present a comprehensive review exploring the pivotal role of plants in mitigating the threat of radioactive pollutants through phytoremediation elucidating its fundamental principles, mechanisms, hyperaccumulating plant species, addressing present challenges, and future research directions for phytoremediation to tackle this critical environmental concern.
Toxic pollutants released from various human activities persistently pose significant threats to living organisms, affecting soil fertility, and impacting human health. Among the various remediation approaches, phytoremediation has gained popularity due to its cost-effectiveness and environmentally friendly characteristics. This method involves utilizing plant species to restore polluted soils, emphasizing the intrinsic abilities of plants to remediate contaminated environments. There are various phytoremediation approaches and combinations that have been developed, ranging from phytoextraction to rhizofiltration, each tailored to specific contaminants and environmental conditions. While acknowledging the slow and time-consuming nature of the phytoremediation process and its potential impact on plant growth and development, this review emphasizes the increasing significance of this eco-friendly approach. Moreover, the exploration suggests that leveraging plant-microbe interactions could enhance the efficiency of remediating contaminated areas. Furthermore, understanding the microbial mechanisms involved in phytoremediation is crucial for optimizing remediation outcomes. Microbes play a pivotal role in enhancing plant tolerance to pollutants, facilitating pollutant degradation, and promoting plant growth in contaminated environments. Harnessing the power of microbial communities through bioaugmentation or stimulating indigenous microbial populations can significantly improve phytoremediation efficiency. Emerging omics technologies and the application of CRISPR/Cas9 technology in phytoremediation offer promising avenues for advancing soil remediation efforts. Omics approaches, including genomics, transcriptomics, proteomics, and metabolomics, provide insights into the genetic and molecular mechanisms underlying plant responses to pollutants and can aid in identifying key genes or pathways for enhancing phytoremediation efficiency. Meanwhile, CRISPR/Cas9 technology presents an innovative solution for targeted genome editing in plants, enabling precise modification of genes involved in pollutant uptake, tolerance, and detoxification. By engineering plants with enhanced capabilities for metal sequestration or pollutant degradation, CRISPR/Cas9 holds tremendous potential for accelerating the remediation of contaminated soils. This comprehensive review serves as a valuable resource for environmental practitioners and scientists, providing insights into both traditional and innovative technologies that have the potential to transform soil remediation practices, ultimately contributing to a cleaner and healthier environment.
The Faculty of Engineering and Technology of the Universidad Autónoma del Carmen (UNACAR), through the Educational Program of the Master's Degree in Materials and Energy Engineering, organized the 5th Master's Student Colloquium, held from August 28 to 31, 2023. The purpose of this event was to provide a space for the dissemination of research topics of the students of the different master's and doctoral programs offered by UNACAR and other graduate programs in the region. It is important to highlight that students from the Universidad Autónoma de Campeche, the Universidad Autónoma del Estado de Morelos, the Benemérita Universidad Autónoma de Puebla, the Universidad Autónoma Metropolitana and the Centro de Investigación Científica de Yucatán - Unidad de Energía Renovable participated in the event.
Phytoremediation is an essential, eco-friendly, cost-effective as well as a sustainable solution to the problems leading to environmental contamination. Phytoremediation may be used in two ways either in situ or ex situ. It requires the use of plants that helps in uptake, accumulation, detoxification, translocation, and volatilization of inorganic and organic pollutants from the contaminated soil and water. The major constraints of phytoremediation are time-consuming process and limited to the accumulation and tolerance of metals from the sites having a high concentration. Thus, to improve and enhance the phytoremediation process there is a need to develop new insights. Biotechnological interventions like genetic engineering to the phytoremediator plant species have been found helpful to speed up the metal accumulation, translocation, and detoxification significantly. The most common host plants tested for phytoremediation are genetically modified (GM), including Nicotiana tabacum, Oryza sativa, Arabidopsis thaliana, Sedum plumbizincicola, etc. Hence in this chapter, we have focused to explore the phytoremediation potential of transgenic plants specially designed for the removal of heavy metals (HMs). With several case studies, the mechanism of GM phytoremediator plants is also discussed in this chapter.
The remediation of heavy metal contaminated mangrove soil with proper washing agents is critical for reducing the harmfulness of heavy metal contaminated soil to the environment. This work is aimed to investigate the potential of natural-based deep eutectic solvents as soil washing agents. Choline chloride (ChCl) and two organic acids, lactic acid and levulinic acid, are used as degradable and natural washing agents to remove Pb in the soil. Results verified that ChCl: Lactic Acid (1:2) [ChCl-LacA] and ChCl: Levulinic Acid (1:2) [ChCl-LevA] were found to be suitable for the removal of Pb from the contaminated soils, which significantly lowers the total Pb concentration in the soil. The high distribution ratio from the Conductor-like Screening Model for Real Solvents (COSMO-RS) screening gave an early indication that natural acid DESs are effective soil washing agents. The effect of washing agent concentration, soil to liquid ratio, contact time, and the interaction between acid DESs and metal ions was evaluated. ChCl-LacA and ChCl-LevA remove lead to 97% and 99%, respectively, under optimum conditions. ICP-MS, XRD, and FTIR spectroscopy analysis clarified the interaction between DES and metal ions. As a washing agent, green and natural DESs provide an environmentally sustainable alternative. Employing soil washing to remove heavy metals is a simple, rapid, and cheap remediation technology that could potentially be used in mitigating soil pollution.
Global developmental strategies and population expansion are continuously showing their odd impacts on the living world, thereby causing stresses of multiple natures. To combat these stresses, hydrogen sulfide (H2S) is well-examined signaling molecule that acts as a priming agent and helps in regulating the response of plants to various stressful conditions. Hydrogen sulfide is formed in the plant cells as an intermediate of an assimilatory sulfate reduction. Despite the endogenous release of hydrogen sulfide, its exogenous application has been found to be beneficial in the amelioration of multiple abiotic stresses. These responses are also mediated by the expression of genes and proteins that participate in signaling and metabolic pathways induced through several small signaling molecules known as plant hormones or phytohormones. Phytohormones are also found to be involved in regulation of the protective responses under various abiotic and biotic stress conditions. H2S in crosstalk with these phytohormones significantly ameliorates the abiotic stress in plants. In this chapter we have discussed in detail how H2S in crosstalk with phytohormones helps in the enhancement of defense against abiotic stress in plants.
Soil contamination by heavy metals due to rapid industrialization and anthropogenic activities is a serious global environmental issue. Heavy metals adversely affect the soil and plant health. Exposure of plants to heavy metals cause oxidative stress due to excessive production of reactive oxygen species (ROS) which result in decreased crop productivity. Hyperaccumulators have well developed antioxidative defense mechanism which protects the plants against the deleterious effects of the oxidative stress generated by heavy metals. Thiols participate in various chemical reactions that are involved in cellular redox homeostasis and detoxification of ROS. GSH is an important antioxidant that plays vital role in protecting the cell from the damage caused due to ROS generation during abiotic stress. Pytochelatins are also involved in metal stress tolerance due to their high antioxidant ability. This chapter sheds light on the role of thiols in metal tolerance in plants.
We evaluated the concentration of copper (Cu), zinc (Zn), mercury (Hg), nickel (Ni), chromium (Cr), vanadium (V), and cobalt (Co) in the mangrove tissues (leaf and root) and adjusted sediments, as well as seawater samples in the north coast of the Persian Gulf from three counties (Mahshahr, Bord Khun, Asaluyeh). Assaluyeh and Mahshahr were selected because of their proximity to the oil and petrochemical industries and Bord Khun was considered for being away from pollution sources. The metal detected in highest concentration in mangrove leaves and roots was Cu (Asaluyeh: 1.507 μg/g and 1.198 μg/g, Bord Khun: 1.812 and 1.756 μg/g, and Mahshahr: 0.880 and 1.617 μg/g, for leaves and roots, respectively). For sediments, Cr (among the metals) had the highest concentration (1.325 μg/g) in Asaluyeh, whereas in Bord Khun and Mahshahr Ni was predominant: 2.542 and 2.237 μg/g, respectively. For seawater, Cu was the most abundant metal and Hg was the one with the lowest concentration. The bio-concentration factor for Zn and Cu revealed that mangroves in the study areas have suitable potential for phytoremediation of these two metals. Translocation factors from the roots to leaves also indicated higher transportability for Zn and Cu through the plant tissues, compared to the other metals. Ecological indexes quantified the contamination of sediments and revealed a low level of heavy metal accumulation in sediments of the north of the Persian Gulf. Human risk hazards appeared low in all the areas under study. Gas and petrochemical activities can be considered as a potential source of the discharge of heavy metals into the aquatic environment.
Arsenic (As) is highly carcinogenic and toxic in nature. Increased levels of As contamination is a threat to health and environment, as it could accumulate into the agricultural soils and enters into the food chain. The conventional strategies of remediation, like capping, landfilling, excavation, and chemical methods for As, are found to be expensive and therefore cause imbalance in the ecosystem. Alternatively, phytoremediation techniques are eco-friendly and remove As from contaminated soil. As-resistant bacteria ameliorate the process of phytoextraction in As-hyperaccumulating plants, such as Pteris vittata. In this review, we have described the prospects of P. vittata, which is an As-hyperaccumulator, for the remediation of As-contaminated soil. The research information available on P. vitatta has been compiled, analysed and presented, with details of its response to As toxicity, mechanism of As uptake and transport, and detoxification/resistance mechanisms, to promote it as a model system for As-phytoremediation. Also, the role of soil microorganisms, which assist P. vittata in the process of As-remediation, has been discussed for improvement of phytoremediation efficiency.
Environmental degradation by contaminants is a serious concern in the developing world. The remediation strategies to overcome the problem of environmental degradation should be assorted for its ecological impacts. Phytoremediation is a green technology for the removal of pollutants from various environmental compartments by employing green plants. An ideal phytoremediation plant candidate should possess some characteristic features such as exhibiting stronger growth traits with high biomass, unpalatable nature, exuberant root system, hyper accumulation of target contaminants accompanied with stress tolerance attributes. The growth of natural vegetation is prevented by the barren and uncongenial conditions prevailing in the contaminated sites, but however invasive plants are capable of establishing themselves on those sites due to their opportunistic incursive nature. Since, it is hard to eradicate an invasive species once after their establishment in a new habitat or ecosystem, they can possibly be controlled by sustainable management through the way of exploiting them in contaminant remediation, thus phytoremediation. Therefore, it is of foremost requisite to determine the ability of invasive species in offering various ecologically viable services including contaminant remediation through scientific exploration. In this review, the implications of using invasive plants in contaminant remediation with accompanying challenges and scopes involved are discussed with the available volume of literatures in contaminant remediation using plants, especially the invasive plants.
A field test was conducted to determine the ability of three plant species to extract ¹³⁷ Cs and ⁹⁰ Sr from contaminated soil. Redroot pigweed ( Amaranthus retroflexus L.), Indian mustard [ Brassica juncea (L.) Czern.], and tepary bean ( Phaseolus acutifolius A. Gray) were planted in a series of spatially randomized cells in soil that was contaminated in the 1950s and 1960s. We examined the potential for phytoextraction of ⁹⁰ Sr and ¹³⁷ Cs by these three species. Concentration ratios (CR) for ¹³⁷ Cs for redroot pigweed, Indian mustard, and tepary bean were 2.58, 0.46, and 0.17, respectively. For ⁹⁰ Sr they were substantially higher: 6.5, 8.2, and 15.2, respectively. The greatest accumulation of both radionuclides was obtained with redroot pigweed, even though its CR for ⁹⁰ Sr was the lowest, because of its relatively large biomass. There was a linear relationship between the ¹³⁷ Cs concentration in plants and its concentration in soil only for redroot pigweed. Uptake of ⁹⁰ Sr exhibits no relationship to ⁹⁰ Sr concentrations in the soil. Estimates of time required for removal of 50% of the two contaminants, assuming two crops of redroot pigweed per year, are 7 yr for ⁹⁰ Sr and 18 yr for ¹³⁷ Cs.
Because of their direct contact with society, urban buses are prioritized targets for air quality improvement. In this study, a sample group of in-use urban old buses powered by compressed natural gas (CNG) and diesel engines was chosen for particle emission analysis. The CNG buses do not have any type of after-treatment, while diesel ones are equipped with a diesel particulate filter (DPF). To measure the lung deposited surface area (LDSA), a possible physical metric of exhaust particles’ toxicity, a diffusion charger-based analyzer was utilized. The measurements were done at different engine speeds in stationary conditions. The results revealed that although the particle mass emission of CNG buses remains at a low level, the number of emitted particles for 75% of the CNG buses (depending on their maintenance conditions) is 10 to 100 times more than the retrofitted diesel ones, with the range of 10⁶ to 10⁷ p/cm³. The rest 25% of the CNG buses were performing the same as the retrofitted diesel ones in terms of exhaust particle number in the range of 10⁵ p/cm³. In addition, the lowest LDSA parameter at low idle engine speed was measured to be 97.8 and 229.4 μm²/cm³ for a CNG and a DPF retrofitted diesel bus, respectively. This result indicates the same and even lower LDSA and surface area and thus the lower possible toxic potentiality of exhaust particles of CNG buses compared to diesel vehicles at DPF downstream. Investigation on the different behavior of the CNG buses in the emission of particles showed the correlation of some aging parameters such as lubricant oil aging mileage with the released particles and the importance of periodic maintenance interval.
Graphical abstract
The study deals with the accumulation of Pb, Zn and Cd in an important mangrove species, Avicennia marina (Forssk.) Vierh., in the Vamleshwar mangrove ecosystem, near Narmada estuary, West coast of Gujarat, India with height differences of 0.5, 1.5, 2.5 meters and carried out under field conditions during October, 2009. The site was located on 21�30�11.55�� N latitude and 72�43�53.68�� E longitude. Mangrove receives heavy metal pollution from upstream areas of Narmada estuary and highly populated settlements. However, little is known about the capacity of mangrove plants to take up and store heavy metals in them. Water, sediment and plant parts such as roots, stems and leaves were analyzed for finding the trace metal accumulation of different height groups by Inductive Coupled Plasma Analyser (ICPA). Amount of the content of metals found in the water, sediment and plant parts were in the order of Pb>Zn>Cd. The average contents of heavy metals in the waters were 57.83 mg l-1 for Pb, 3.89 83 mg l-1 for Zn and 0.42 mg l-1 for Cd. It was observed that the average contents of Pb (73.6 mg l-1), Zn (8.1 mg l-1) and Cd (0.73 mg l-1) in the sediments were below the critical soil concentrations. The concentrations of heavy metals in different parts of Avicennia marina were in the order Roots>stem>leaf except for Cd, but Cd found higher in leaf. The ranges of the content of heavy metals in plants were 18.5-102.2 mg l-1 for Pb, 3.5-19.5 mg l-1 for Zn and 0.2-4.1 mg l-1 for Cd. The concentrations of all heavy metals in Avicennia marina except Pb were falling within the normal range and were much more in the plants have the highest height. The present study has shown the potential of Avicennia marina as a phytoremediation species for selected heavy metals in many mangrove ecosystems.
Soil contamination by cadmium (Cd) poses a serious environmental and public health concern. Phytoremediation, i.e., the use of plants to remove contaminants from soil, has been proposed for treatment of Cd-contaminated ecosystems. In this study, we demonstrated the potential of Vetiveria zizanioides, commonly known as vetiver, to serve as an effective phytoremediation agent. Two ecotypes, i.e., India and Sri Lanka, were grown in greenhouse pots and in the field. Soils were amended with cow manure, pig manure, bat manure, and an organic fertilizer. Among all amendments, pig manure performed best in both greenhouse and field studies in terms of increasing total V. zizanioides biomass production in both ecotypes. In both greenhouse and in the field, tissue of the Sri Lanka ecotype had higher Cd concentrations than did the India ecotype. In the greenhouse, the presence of Cd did not affect total biomass production or root dry weight. The Sri Lanka ecotype had 2.7 times greater adventitious root numbers and 3.6 times greater Cd accumulation in roots than did the India ecotype. In the field study, the Sri Lanka ecotype offers potential as an excluder species, as it accumulated Cd primarily in roots, with translocation factor values <1 and a bioconcentration coefficient for roots >1 for all experiments except for the pig manure amendment. In addition, the highest Cd concentration in the Sri Lanka ecotype root (71.3 mg kg(-1)) was consistent with highest Cd uptake (10.4 mg plant(-1)) in the cow manure treatment. The India ecotype contained lower root Cd concentrations, and Cd accumulation was slightly higher in shoots compared to roots, with translocation factor (TF) values >1. The India ecotype was therefore not considered as an excluder in the Cd-contaminated soil. With the use of excluder species combined with application of organic amendments, soil contamination by Cd may be treated by alternative remediation methods such as phytostabilization.
Greenhouse and field experiments were conducted to evaluate the influence of three different organic amendments (cow manure, pig manure, and organic fertilizer) on the Cd phytostabilization potential of Eucalyptus camaldulensis grown on Cd-contaminated soil. The application of all amendments, particularly organic fertilizer, improved plant growth (i.e., height and biomass production) when compared to the control (Cd-contaminated soil alone), in both greenhouse and field experiments. E. camaldulensis treated with organic fertilizer experienced the greatest height (39 cm and 3.8 m) and biomass production (2.0 g and 3.3 kg) in greenhouse and field experiments, respectively. Plants grown on amended soils had lower Cd accumulation than those grown on the Cd soil alone. Among the treatments, organic fertilizer resulted in a translocation factor < 1 and a bioconcentration factor for the root (BCFR) > 1, indicating the potential of this species to stabilize Cd in the roots. The results showed that E. camaldulensis is a promising species for phytostabilization of Cd-contaminated soil. The wood of the mature tree is used in the manufacture of commercial products; given the low Cd uptake by E. camaldulensis, it is feasible to harvest the wood grown on Cd-affected soils for making paper and furniture.
In a mangrove forest in Pattani Bay, Thailand, rhizosphere soil and leaf, stem and root tissue from various plant species were tested for concentrations of Cd, Cr, Cu, Mn, Ni, Pb and Zn. Of these metals, Pb concentrations in the mangrove sediment were somewhat elevated. Mn occurred in highest concentrations in tissue of all mangrove species whereas Cd contents were lowest. Both sediment physicochemical properties (e.g., pH, EC, redox potential) and plant species characteristics have likely influenced metal concentrations in plant tissue. Several mangrove species fit the criteria for excluder plants as they accumulated metals mainly in roots, with a resultant translocation factor (TF) < 1 and a bioconcentration factor (BCF) > 1. These include Cyperus involucratus for Cu, Ipomoea pes-caprae for Zn, Typha angustifolia for Mn, and Phragmites karka for Pb. Furthermore, some species have accumulator potential, as metals accumulated in aboveground biomass (leaves and stem), and have TF > 1 and BCF > 1; however, these species (e.g., Thespesia populnea for Ni and C. involucratus for Cr) did not accumulate metals to the extent that they fit the criteria for hyperaccumulators. Continued investigation of metals in sediment and plant organs must be carried out to determine additional species suitable for phytoremediation, and to ensure healthy food chains in coastal ecosystems.
Concentrationsofnatural radionuclides226Ra, 232Th and 40K as well as the radiological hazard parameterswere calculated inthe marine sediments inthreeregions in Quseircity along the Red Sea coast; El-Edua area,Phosphate Harbourandnorth Flaminko Village.The average activity concentrations of226Ra, 232Th and 40K at El-Edua areawere,24.9±3, 19.6±2.4and 234.5±43 Bq.kg-1and at QuseirHarbourrecorded the average activities concentrations were;26.2±3.2, 19.4±2.8and 458.6±164.2Bq.kg-1while at north Flaminko Village found to be;25.7±6.9, 22.6±5and 106.4±17.5Bq.kg-1respectivelyin Quseir city, Egypt.Concentrations of the metals; Mn, Zn, Cu, Pb, Ni, Co and Cd were determined by Atomic Absorption Spectrophotometry (AAS) using GBC-932ver.1.1with detection limits of 0.01 ppm
The activity concentrations of naturally occurring and anthropogenic radionuclides in soil, grass and plant were measured in this work with an aim to determine the transfer factors of radionuclides from soil to grass and plant collected from Chittagong city in Bangladesh. The average activity concentrations of 226Ra, 232Th, 228Th, 40K and 137Cs in soil were found to be 22.13 ± 2.30, 38.47 ± 2.72, 50.47 ± 4.75, 451.90 ± 24.89 and 2.41 ± 0.18 Bq kg-1 respectively while in grass, their values were 1.26 ± 0.11, 3.66 ± 0.31, 7.02 ± 0.49, 134.95 ± 3.68 and 0.17 ± 0.02 Bq kg-1 respectively. In branches of the plant, the concentration values of these radionuclides are higher than those for leaves. For soil to grass, the transfer factor values were found to be 0.056, 0.089, 0.137, 0.275 and 0.054 respectively for 226Ra, 232Th, 228Th, 40K and 137Cs. For plant, soil to branch transfer factor values (0.062, 0.098, 0.136, 0.274 and 0.064 respectively for 226Ra, 232Th, 228Th, 40K and 137Cs) are higher than those for soil to leaves (0.054, 0.088, 0.127, 0.266 and 0.061 respectively).
There is widespread contamination of the environment of the Niger Delta, which may include enhanced background levels of naturally occurring radioactive materials (NORM) due to oil production and rapid urbanization activities. Sediments and seafood from the Bonny estuary, Niger Delta, were collected for the purpose of determining baseline data on artificial and natural radioactivity and estimation of effective doses for the public due to ingestion of seafood from the study area. The highest and lowest activity concentrations were reported for 40 K and 137 Cs in both sediments and fish samples of the Bonny estuary. There was some evidence of spatial variability in the 40 K and 137 Cs data, with the latter being the likely result of dredging. Other radionuclides were not significantly different between sites impacted by industrial activities or not. Activity of radionuclides measured in the sediments of the study area were higher than reported elsewhere in the Niger Delta and Nigeria and higher than reported global averages by UNSCEAR. The total highest activity concentration in all fish species of gamma emitting radionuclides was observed for 40 K, followed by 238 U, 232 Th and 226 Ra, respectively, while 137 Cs had the lowest activity concentration. However, 210 Po activities were the most important in terms of dose contribution. Consumption of molluscs at typical rates could result in doses exceeding 1 mSv· y −1. Although this baseline data may not be conclusive on prevailing trends in radioactivity in the study area, higher OPEN ACCESS Challenges 2015, 6 245 consumption rates of the species studied may have public health consequences due to effects of low dose ionising radiation.
Mangroves are essential for protecting coastal environments and biodiversity; however few studies encompass the distribution of radionuclides in soils from these ecosystems. By applying high resolution gamma-ray spectrometry, natural radionuclides were quantified in soils from the Chico Science Mangrove and Rio Formoso Mangrove (RFM), areas subjected to different human impacts. The activity concentrations of 226Ra and 228Ra were quite similar for the mangroves despite the differences found for 40K. Moreover, no correlation with the environmental impacts on the mangroves was observed, although RFM soil was 40K-enriched compared to deep sediments from other estuaries in the world.
Interest in mangrove rehabilitation has increased rapidly since 2003, as has awareness of the damaging effects of natural and anthropogenic pressures that contribute to mangrove loss, which is estimated at 1-2 % per annum. The major pressures are from urbanization and other development in all areas and forestry and fisheries especially where communities depend on mangroves for their livelihood. However rehabilitation success has been uncertain, reflecting gaps in integration between human and ecological components of the rehabilitation system. In particular there are government level issues of gaps and inconsistency in policy and failure in application. Some rehabilitation efforts have had limited success for several reasons including: having insufficient information, using inappropriate methods, not involving local communities, or not following all the steps in the processes that have been identified in the literature. A multi-disciplinary and integrated approach is needed to assist future planning and this needs capacity from a variety of areas in government, research and community. The review concludes with hope for a future where governments work with communities to develop policies and strategies for rehabilitating mangrove for resilience to changing environments.
The present study evaluated the antimutagenic and anticancer activities of A. marina leaf extract. The antimutagenic activity of ethanol and water extracts of A. marina leaf (concentration 10 mg/plate for 48 h) was evaluated using the Salmonella typhimurium TA100 strain in the Ames test with (+S9) and without (-S9) metabolic activation, and its anticancer effect with concentrations of 200, 400, 450, 500, 600, and 800 mu g/ml of ethanol extract for 24, 48, and 72 h on human leukaemic cell line HL-60 was assessed by MIT assay. The ethanol and water extracts of A. marina were revealed to have antimutagenic activity in the Salmonella mutation assay. The number of mutant colonies decreased in the presence of ethanol and water extract with (+S9) and without(-S9) metabolic activation. The ethanol extract showed a higher antimutagenic effect than the water extract, with an inhibition rate of 71% on the mutated bacterium. The MIT cell viability test showed an induction of cytotoxicity in HL-60 cells treated with the extract with 1050 values of 600, 400, and 280 mu g/ml after 24, 48, and 72 h, respectively, in a concentration and time-dependent manner. Flow cytometric analysis confirmed the induction of apoptosis in the cells. Collectively, these results suggest that the Avicennia marina leaf extract contains bioactive compounds with antimutagenic and antileukaemic effects.
Natural radioactive concentration analysis was carried out in the sand sediments that were collected from
the shallow inner shelf region of an ecologically sensitive mangrove forest area at Krusadai Island in Gulf
of Mannar near Rameswaram, Tamil Nadu, India. A NaI (Tl) detector based gamma ray spectrometer was
used for analysing the samples. The Activity concentration of the primordial radionuclide 238U was below
detectable limit (BDL) for all the locations, 232Th had the range between BDL to 27.81 ± 8.9 Bq/kg while
40K had the range from BDL to 413.13 ± 49.6 Bq/kg. The other radiological parameters were calculated
and all are found to be well below the prescribed limit. The study concludes that the Krusadai island
mangrove forest region as a radiologically safer region for the endemic biota.
Constructed root-channel wetland (CRCW) is a term for pre-pond/wetland/post-pond complexes, where the wetland includes plant-bed/ditch landscape and root-channel structure. Source water out of pre-ponds flows through alternate small ditches and plant beds with root-channels via a big ditch under hydraulic regulation. Then source water flows into post-ponds to finish final polishing. This article aims to explore the potential of components of a pilot CRCW in China on mitigating metals in micro-polluted source water during its initial operation stage. We investigated six heavy metals (Cd, Cr, Cu, Ni, Zn, and Pb) in surface sediment, plant-bed subsurface soil, water, and aquatic plants during 2012–2013. Monitoring results showed that pond/ditch sediments and plant-bed soil retained a significant amount of Cr, Ni, and Zn with 93.1%, 72.4%, and 57.5% samples showing contamination factor above limit 1 respectively. Remarkably the high values of metal enrichment factor (EF) occurred in root-channel zones. Water monitoring results indicated that Ni, Zn, and Pb were removed by 78.5% (66.7%), 57.6% (59.6%), and 26.0% (7.5%) in east (west) wetland respectively. Mass balance estimation revealed that heavy metal mass in the pond/ditch sediments accounted for 63.30% and that in plant-bed soil 36.67%, while plant uptake occupied only 0.03%. The heavy metal accretion flux in sediments was 0.41 - 211.08 μg · cm-2 · a-1, less than that in plant-bed soil (0.73 - 543.94 μg · cm-2 · a-1). The 1.83 ha wetland has retained about 86.18 kg total heavy metals within 494 days after operation. This pilot case study proves that constructed root-channel wetland can reduce the potential ecological risk of purified raw water and provide a new and effective method for the removal of heavy metals from drinking water sources.
Electronic supplementary material
The online version of this article (doi:10.1186/2193-1801-3-326) contains supplementary material, which is available to authorized users.
Pot and field experiments were conducted to elucidate the phytostabilization potential of two grass species (Thysanolaena maxima and Vetiveria zizanioides) with respect to lead (Pb) tailing soil. Three fertilizers (Osmocote® fertilizer, cow manure, and organic fertilizer) were used to improve the physicochemical properties of tailing soil. V. zizanioides treated with organic fertilizer and cow manure showed the highest biomass (14.0 ± 2.6 and 10.5 ± 2.6 g per plant, respectively) and the highest Pb uptake in the organic fertilizer treatment (T. maxima, 413.3 μg per plant; V. zizanioides, 519.5 μg per plant) in the pot study, whereas in field trials, T. maxima attained the best performances of dry biomass production (217.0 ± 57.9 g per plant) and Pb uptake (32.1 mg per plant) in the Osmocote® treatment. In addition, both grasses showed low translocation factor (1). During a 1-year field trial, T. maxima also produced the longest shoot (103.9 ± 29.7 cm), followed by V. zizanioides (70.6 ± 16.8 cm), in Osmocote® treatment. Both grass species showed potential as excluder plants suitable for phytostabilization applications in Pb-contaminated areas.
Metals occur in soils through natural and anthropogenic sources. Metals enter into the human food chain through plant uptake and thus cause human health problems. Different techniques are used for the safe use of metal contaminated soils. Growing plants to remediate metal contaminated soils (Phytoremediation) is a good technique for soils with low to moderate level of metal contamination. However, adverse growth conditions due to low fertility, metal toxicity and phyico-chemical conditions restricted the plant growth. Addition of amendments to immobilize the metals is common practice to detoxify the metals in the soils. Among amendments, organic amendments are important due to their role to improve soil physico-chemical, biological properties and nutrient availability and thus favor the plant growth and re-vegetation of contaminated soils. Organic amendments undergo transformation with time due to decomposition of organic matter and thus their effect on phyto-availability of metals is greatly altered. However, the immobilizing effect of organic amendments at the initial stage after their application is important for re-vegetation of metal contaminated soils. In this chapter, we have discussed the role of organic amendments to immobilize metals, improve plant growth and subsequent release of metals due to decomposition of organic matter.
Fifty three samples of different types of imported and locally produced drinks consumed in the central zone of Malaysia were analyzed using gamma-ray spectrometry system equipped with a high purity germanium (HPGe) detector. The activity concentrations of the natural radionuclides 238 U, 232 Th and 40 K present in the studied samples were measured and the radium equivalent activities Ra eq were calculated. In addition, the radiation hazard index (HI) was calculated. The average concentrations of 238 U, 232 Th and 40 K were 0.69 ± 7×10¯ 4 , 1.3 ± 8×10¯ 4 and 20.52 ± 6×10¯ 4 Bq/Kg, respectively. The values of Ra eq were between 0.002 and 10.0 Bq/kg. The HI were between 0.002 and 0.03, which is below one (the higher limit of HI). The results obtained were compared to the standard accepted international values and found to be within the acceptable limits. Keywords: Activity concentration; NORM; radiation hazard index; radium equivalent; 238 U, 232 Th and 40 K ABSTRAk Lima puluh tiga sampel daripada pelbagai jenis minuman tempatan dan import yang terdapat di zon tengah Malaysia dianalisis menggunakan sistem spektroskopi sinar dengan pengesan germanium berketulenan tinggi (HPGe). Kepekatan radionuklid, tabii 238 U, 232 Th dan 40 K dalam sampel diukur dan setara radium Ra eq dikira. Selain itu, indeks bahaya sinaran (HI) juga dikira. Kepekatan aktiviti 238 U, 232 Th dan 40 K dalam sampel berada dalam julat 0.69 ±7×10¯ 4 , 1.3 ±8×10¯ 4 dan 20.52 ± 6×10¯ 4 Bq/Kg. Nilai Ra eq berada dalam julat antara 0.002 dan 10.0 Bq/kg. Indeks bahaya sinaran (HI) berada dalam julat antara 0.002 dan 0.03, kurang daripada satu (had atas HI). Keputusan yang diperoleh dibandingkan dengan piawai di peringkat antarabangsa dan didapati berada dalam julat yang boleh diterima. Kata kunci: Indeks bahaya sinaran; kepekatan aktiviti; kesetaraan radium; NORM; 238 U, 232 Th dan 40 K InTRoDuCTIon
Marine ecosystem is a complex nonlinear system. However, ecosystem health assessment conventionally builds on a linear superposition of changes in ecosystem components and probably fails to evaluate nonlinear interactions among various components. To better reflect the intrinsic interactions and their impacts on ecosystem health, an ecosystem coordination index, defined as the matching level of ecosystem structure/services, is proposed and incorporated into the ecosystem health index for a systematic diagnosis in the Pearl River Estuary, China. The analysis results show that the ecosystem health index over the last three decades decreased from 0.91 to 0.50, indicating deteriorating from healthy to unhealthy status. The health index is 3-16% lower than that calculated using the common method without considering ecosystem coordination. Ecosystem health degradation in the Pearl River Estuary manifested as significant decreases in structure/services and somewhat mismatching among them. Overall, the introduction of coordination in ecosystem health assessment could improve the understanding of the mechanism of marine ecosystem change and facilitate effective restoration of ecosystem health.
Plants colonizing metalliferous soils have evolved physiological mechanisms which enable them to tolerate metal toxicity. These mechanisms do not generally suppress metal uptake but result in internal detoxification. Two basic strategies of plant response are suggested, accumulators and excluders. In the former, metals can be concentrated in plant parts from low or high background levels. By contrast, differential uptake and transport between root and shoot in excluders, lead to more or less constant low shoot levels over a wide range of external concentration. ‘Indicators’ are seen as a further mode of response where proportional relationships exist between metal levels in the soil, uptake and accumulation in plant parts. The physiological properties of accumulator and excluder species are considered in relation to metal tolerance mechanisms.
The application of nuclear energy and the use of radionuclides for industrial, medical, and research purposes have caused significant contamination of certain sites and their environments, which could result in health problems for several centuries if nothing is undertaken to remedy these situations. Except for the close environment of the facility, where decontamination activities may be feasible and affordable, the contamination often extends over a vast area and decontamination would result in considerable amounts of waste. Therefore, a search should be conducted for more realistic, yet efficient, remediation options; phytomanagement is among the potential options.
Little is known regarding phytoremediation of radionuclides from soil; even less is known about radionuclide contamination and removal in tropical ecosystems such as mangrove forests. In mangrove forests in Pattani Bay, Thailand, 18 plant species from 17 genera were evaluated for radionuclide concentrations within selected plant parts. Two shrub species, Avicennia marina and Pluchea indica, accumulated the highest (232)Th (24.6Bqkg(-1)) and (40)K (220.7Bqkg(-1)) activity concentrations in roots, respectively. Furthermore, the aquatic species Typha angustifolia accumulated highest (232)Th, (40)K and (226)Ra activity concentrations (85.2, 363.5, 16.6Bqkg(-1), respectively) with the highest transfer factors (TFs) (3.0, 2.0, 5.9, respectively) in leaves. Leaves of T. angustifolia had an absorbed dose rate in air (D) over the recommended value (74.8nGyh(-1)) that was considered sufficiently high to be of concern for human consumption.
Malaysia, a rapidly growing industrial country, is susceptible to pollution via large-scale industrial engagements and associated human activities. One particular concern is the potential impact upon the quality of locally resourced vegetables, foodstuffs that contain important nutrients necessary for good health, forming an essential part of the Malaysian diet. As a part of this, it is of importance for there to be accurate knowledge of radioactive material uptake in these vegetables, not least in respect of any public health detriment. Herein, using HPGe γ-ray spectrometry, quantification has been performed of naturally occurring radionuclides in common edible vegetables and their associated soils. From samples analyses, the soil activity concentration ranges (in units of Bq/kg) for (226)Ra, (232)Th and (40)K were respectively 1.33-30.90, 0.48-26.80, 7.99-136.5 while in vegetable samples the ranges were 0.64-3.80, 0.21-6.91, 85.53-463.8. Using the corresponding activities, the transfer factors (TFs) from soil-to-vegetables were estimated, the transfers being greatest for (40)K, an expected outcome given the essentiality of this element in support of vigorous growth. The TFs of (226)Ra and (232)Th were found to be in accord with available literature data, the values indicating the mobility of these radionuclides to be low in the studied soils. Committed effective dose and the associated life-time cancer risk was estimated, being found to be below the permissible limit proposed by UNSCEAR. Results for the studied media show that the prevalent activities and mobilities pose no significant threat to human health, the edible vegetables being safe for consumption.
Tigris and Euphrates rivers both emerge in eastern Turkey and cross Syria and Iraq. They unite to Shatt al-Arab/Arvand Rud River and discharge in Arabic/Persian Gulf. The activity concentration of natural and anthropogenic radionuclides was measured during the August of 2011 in a number of surficial sediment samples collected from the seabed along an almost straight line beginning near the estuary mouth and extending seaward. The results exhibited low activity concentration levels and an almost homogeneous spatial distribution except locations where sediment of biogenic origin, poor in radionuclides, dilute their concentrations. Dose rates absorbed by reference marine biota were calculated by the ERICA Assessment Tool considering the contribution of 40 K. The results revealed a relatively low impact of 40 K mainly to species living in, on and close to the seabed. Also, statistical association of radionuclides with selected stable elements (Ca, Ba and Sr) did not indicate presence of by-products related with oil and gas exploitation and transportation activities. Moreover, a semi-empirical sedimentology model applied to reproduce seabed granulometric facies based entirely on radionuclides activity concentrations.
A dated sediment core from a highly-fertilized mangrove wetland located in Cubat~ ao (SE Brazil) presented a negative correlation between mercury (Hg) and organic carbon contents. This is an unusual result for a metal with well-known affinity to organic matter. A dilution of Hg concentrations by autochthonous organic matter explained this observation, as revealed by carbon stable isotopes signatures (d 13 C). Mercury dilution by the predominant mangrove-derived organic matter counterbalanced the positive influences of algal-derived organic matter and clay contents on Hg levels, suggesting that deleterious effects of Hg may be attenuated. Considering the current paradigm on the positive effect of organic matter on Hg concentrations in coastal sediments and the expected increase in mangrove organic matter burial due to natural and anthropogenic stimulations of primary production, predictions on the influences of organic matter on Hg accumulation in mangrove wetlands deserve caution.
The main objective of this study was to evaluate the spatial distribution and ecological risk of the heavy metals in soils around the industrial non-point source in the western town of Yixing city, an area with intensive industrialization in Yangtze River Delta of China. Investigated were the elements of Cd, Cr, Cu and Pb in topsoil with different distances in all the four directions from the industrial town (east, west, south, and north direction, respectively). Results show that Cd, Cr, Cu and Pb element are slightly accumulated, appreciably higher than the background values. The heavy metals concentrations in the west direction evidently exceed in the other three directions. The mainly reason is due to the subtropical monsoon climate and a large amount of discharged waste situated in the west of industrial town. This study also finds that almost all heavy metals show low correlation with the distance in the westward direction but significantly correlation with the increasing distance in the east direction. It is because of a combined effect of heavy metals in soils around non-point source. However, compared with point source, a decreasing trend with increasing distance due to non-point source is not evident, but the polluted territorial scope is wider. By means of correlation analysis, trace metals source in different directions is different around the industrial non-point source. Pb and Cu contaminants are the mainly polluted source in all four directions, especially in the western and eastern direction. Moreover, there are many industrial Cr contaminants in the northward direction and Cd contaminant at the south side of the industrial town is one of mainly contamination sources. The ecological risk assessment results show that all the soil heavy metals around non-point source are at low or moderate risk by the use of catastrophe progression method. Due to the combined effect of soil heavy metals, the ecological risk indices do not evidently change with the increasing distance in all the four directions. It is concluded that the ecological risk due to non-point source is wider than that due to point source.
This paper deals with the absorption, accumulation and distribution of several heavy metals in Avicennia marina community at Futian Nature Reserve in Shenzhen, China. The results showed that: (1) the contents of Cu, Pb, Zn, Cd, Cr, Ni and Mn in the topsoil(0-30cm in depth) were 38.3, 28.7, 11.4, 0.136, 7.97, 25.0 and 537 μg/g respectively; (2) there were significant differences in the contents of heavy metals in different fractions of Avicennia marina, and the content ranges were 1.8-13.8 for Cu, 0.4-3.51 for Pb; 3.4-69.5 for Zn, 0.013-0.295 for Cd, 0.28-0.73 for Cr, 0.43- 7.65 for Ni and 25-1552 μg/g for Mn; (3) The enrichment coefficient (weighted mean) of the plants to topsoil was Cd>Mn>Zn>Cu>Ni = Cr>Pb; (4) the accumulation amounts of seven elements in standing biomass of this community were 53.70, 19.27, 187.89, 0.72, 6.06, 20.76 and 1631.17 mg/m2 for Cu, Pb, Zn, Cd, Cr, Ni and Mn respectively. The net retention amount in the community (1993) were 4.06, 1.32, 16.36, 1.43, 107.98 mg/(m2.a) for Cu, Pb, Zn, Ni and Mn, 60.21 and 431.80μg/(m2.a) for Cd and Cr respectively; (5) the potential amounts of the elements which existed in the residues of soil surface in the community were 2.09, 1.96, 5.05, 1.54 and 405.54 mg/m2 for Cu, Pb, Zn, Ni and Mn, and which of Cd and Cr were 19.30 and 78.00 μg/m2, respectively.
Estuaries are sinks of materials and substances which are released directly into them or transported from rivers that drain the basin. It is usual to find high organic matter loads and fine particles in the sediments. We analyzed radionuclide concentrations ((210)Po, (230)Th, (232)Th, (234)U, (238)U, (226)Ra, (228)Th, (228)Ra, (40)K) in sediments and three different organs (roots, stems and leaves) of three species of halophytes plants (Spartina maritima, Spartina densiflora and Sarcocornia perennis). The study was carried out in two tidal salt marshes, one polluted by U-series radionuclides and another nearby that was unpolluted and was used as a control (or reference) area. The Tinto River salt marsh shows high levels of U-series radionuclides coming from mining and industrial discharges. On the contrary, the unperturbed Piedras River salt marsh is located about 25 km from the Tinto marsh, and shows little presence of contaminants and radionuclides. The results of this work have shown that natural radionuclide concentrations (specially the U-isotopes) in the Tinto salt marsh sediments are one order of magnitude higher than those in the Piedras marsh. These radionuclide enhancements are reflected in the different organs of the plants, which have similar concentration increases as the sediments where they have grown. Finally, the transfer factor (TF) of the most polluted radionuclides (U-isotopes and (210)Po) in the Tinto area are one order of magnitude higher than in the Piedras area, indicating that the fraction of each radionuclide in the sediment originating from the pollution is more available for the plants than the indigenous fraction. This means that the plants of the salt marshes are unhelpful as bioindicators or for the phytoremediation of radionuclides.
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A baseline investigation into heavy metal status in the mangrove sediments was conducted in Shenzhen, China where rapid urban development has caused severe environmental contamination. It is found that heavy metal contamination in this mangrove wetland is characterized by the dominant presence of tungsten and cobalt, which is markedly different from the neighboring Hong Kong and other parts of the world. The vertical variation pattern of these two metals along the sediment profile differed from other heavy metals, suggesting an increasing influx of tungsten and cobalt into the investigated mangrove habitat, as a result of uncontrolled discharge of industrial wastewater from factories that produce or use chemical compounds or alloys containing these two heavy metals. Laboratory simulation experiment indicated that seawater had a stronger capacity to mobilize sediment-borne tungsten and cobalt, as compared to deionized water, diluted acetic, sulfuric and nitric acids.
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Levels of the heavy metals Copper (Cu), Zinc (Zn), Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni), Iron (Fe) and Manganese (Mn) were determined in coastal water, sediments and soft tissues of the Saccostrea cucullata, from the intertidal zone at five stations in the Gulf of Chabahar on the Iranian coasts along the Oman Sea. The concentrations of heavy metals in seawater ranged between 3.37 to 5.74, 18.01 to 22.62, 4.24 to 4.52, 0.15 to 0.19, 20.16 to 21.46, 16.42 to 17.14, 15.43 to 24.76 µg L-1 and 7.06 to 8.67 µg L-1 for Cu, Zn, Pb, Cd, Cr, Ni, Mn and Fe, respectively. The corresponding concentration values in the sediments were 46.79 to 54.76, 40.14 to 43.12, 25.63 to 28.23, 0.53 to 0.63, 47.16 to 51.43, 26.45 to 28.68, 52.13 to 53.46 and 84.42 to 89.14 µg g-1 for Cu, Zn, Pb, Cd, Cr, Ni, Fe and Mn, respectively. The highest accumulated metals were Zn, Cu and Mn in, S. cucullata while the lowest one was Cd. The highest concentrations of all metals in seawater, sediments and Oyster were recorded at Tiss harbour eastern parts of the Gulf, while the lowest concentrations were recorded at Damagheh. Based on this research, land based activities; shipping activity and the sewage disposal from vessels and residential area close to these harbors are the main source of metal pollution in the Gulf of Chabahar.
Key words: Heavy metals, seawater, sediment, Saccostrea cucullata, Oman Sea, Gulf of Chabahar.
The radioactivity concentration of (238)U, (232)Th, (226)Ra, (40)K, and (137)Cs in soil samples collected in a coastal wetland of the Southern Laizhou Bay, China were measured. Mean activity concentrations were 54.4±11.7, 57.9±9.7, 28.6±4.3, 542±21, and 10.2±2.9Bqkg(-1) dry weight for (238)U, (232)Th, (226)Ra, (40)K and (137)Cs, respectively. Statistical analyses suggested significant correlations between clay content and (40)K as well as (137)Cs. The radium equivalent activity, the absorbed dose rate in the air at 1m above the ground surface, and the external hazard index were calculated. The result showed that the radioactivity level in the wetland was in normal range. But sites along the river tended to have higher radiological hazard indexes. The vertical distributions of radionuclides in profiles illustrated some phenomena, such as vertical transport of (238)U, disequilibrium between (238)U and (226)Ra, and change in material sources.
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Phytoremediation, the use of plants and associated microorganisms to eliminate environmental damage or threats posed by environmental pollution, never managed to live up to its expectations, because of long-term restrictions in land use. The recently developed phytomanagement bypasses this drawback by incorporating the aspect of economic revenue production into phytoremediation. Phytomanagement regards contaminated soils not as a problem but as an economic opportunity and a valuable resource that should be used sustainably. The product variety ranges from timber and pulp, over fodder and fertilizers up to pharmaceuticals. Phytomanagement could thus not only offer ecological benefits but offer also economic relief to communities that live near contaminated sites. Plant research could assist in achieving that goal by identifying new marketable plant species, by developing new crop management schemes (e.g. intercropping) and by developing new transgenic plants.
Abstract The work investigates on the potential of ten mangrove species for absorption, accumulation and partitioning of trace metal(loid)s in individual plant tissues (leaves, bark and root/pneumatophore) at two study sites of Indian Sundarban Wetland. The metal(loid) concentration in host sediments and their geochemical characteristics were also considered. Mangrove sediments showed unique potential in many-fold increase for most metal(loid)s than plant tissues due to their inherent physicochemical properties. The ranges of concentration of trace metal(loid)s for As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn in plant tissue were 0.006- 0.31, 0.02- 2.97, 0.10- 4.80, 0.13- 6.49, 4.46- 48.30, 9.2- 938.1, 0.02- 0.13, 9.8- 1726, 11- 5.41, 0.04 - 7.64, 3.81- 52.20 µg g (-1)respectively. The bio-concentration factor (BCF) showed its maximum value (15.5) in Excoecaria agallocha for Cd, suggesting that it can be considered as a high-efficient plant for heavy metal bioaccumulation. Among all metals, Cd and Zn were highly bioaccumulated in E. agallocha (2.97 and 52.2 µg g (-1)respectively. Our findings suggest that the species may be classified as efficient metal trap for Cd in aerial parts, as indicated by higher metal accumulation in the leaves combined with BCF and translocation factor (TF) values.
The paper reports on the study of artificial radionuclide accumulation in agricultural crops grown at the territory with high concentration of radionuclides, and first of all - with high concentration of transuranium elements. As a result of this work, peculiarities of accumulation and distribution of artificial radionuclides in the vegetative and generative organs of the studied plants have been revealed. Basic accumulation factors have been found for (137)Cs, (90)Sr, (239+240)Pu, and (241)Am in agricultural products. Accumulation factor dependence on type of planting was found for the investigated types of plants. It has been found that the vegetative organs accumulate radionuclides most of all.
In the present study, measurements of naturally occurring radioactive materials and 137Cs activity in sediment were conducted for locations covering the entire Burullus Lake in order to gather information about radionuclides mobility and distribution. Low-background γ-spectrometry was employed to determine the activity concentrations of water and sediment samples. The activity concentrations of 226Ra and 232Th are close to uniform distribution in the lake environment. Among the different physical and chemical characteristics measured for water and sediment, only salinity and total organic matter content have the potential to affect the mobility of 137Cs and 40K. The results suggest that these two radionuclides are attached to different mobile particulates. Increasing salinity tends to strengthen the adsorption of 137Cs and solubilization of 40K in sediment. On the other hand, sediment with high organic matter content traps 137Cs and 40K associated particulates to bottom sediment.
A field investigation was conducted for the vegetation composition and (226)Ra uptake by native plant species at a uranium mill tailings impoundment in South China. 80 species belonging to 67 genera in 32 families were recorded in the sampling sites. The Poaceae and Asteraceae were the dominant families colonizing the impoundment. The number of the plant species and vegetation community composition in the sampling sites seemed most closely related to the activities of (226)Ra and the pH value of the uranium tailings. The plant species in the sampling sites with relatively low activities of (226)Ra and relatively high pH value formed a relatively stable vegetation community. The plant species in the sampling sites with medium activities of (226)Ra and medium pH value formed the transitional vegetation community. The plant species in the sampling sites with relatively high activities of (226)Ra and relatively low pH value formed a simple unstable vegetation community that was similar to that on the unused grassland. The activities of (226)Ra and transfer factors (TFs) varied greatly with the plant species. The high activities of (226)Ra and TFs were found in the leaves of Pteris multifida (150.6 Bq/g of AW; 9.131), Pteridium aquilinum (122.2 Bq/g of AW; 7.409), and Dryopteris scottii (105.7 Bq/g of AW; 6.408). They satisfied the criteria for a hyperaccumulator for (226)Ra. They may be the candidates for phytoremediation of (226)Ra in the uranium mill tailings impoundment areas and the contaminated soils around.
Chemical speciation of lead (Pb) and cadmium (Cd) in the coastal and estuarine sediments along the central east coast of India was studied by applying sequential and kinetic extraction methods. The results of this study suggest that concentrations of non-residual and dynamic complexes (which are good indicators of bioavailability) of these toxic metals gradually increase with increasing total metal loading in sediments.Increase in bioavailability of these toxic metals with increasing total metals concentrations in the sediments can be a potential threat to benthic organisms and aquatic biota in the system. This study shows that total organic carbon (TOC) is one of the key factors which play a crucial role in controlling speciation of these toxic metals in sediments. However, distribution and speciation of these metals are influenced by their total metal loading and trace metal competitions rather than only TOC content in sediments.An attempt was made to identify the key factors which control speciation of these toxic metals in natural system and provides a better understanding to predict and control pollution of Pb and Cd in coastal and estuarine sediments.
The behaviour of 134Cs, 110mAg and 85Sr was studied in different soil-plant systems, using two types of Mediterranean soil with contrasting properties (sandy and sandy-loam soils). The plant species used was lettuce (Lactuca sativa). Contamination was induced at different stages of plant growth, using a synthetic aerosol which simulated a distant contamination source.Characterisation of aerosol and soils, interception factors in the various growth stages, foliar and root uptake, leaching from leaves by irrigation and distribution and migration of radionuclides of soils were studied, in an attempt to understand the key factors involving radionuclide soil-to-plant transference.
Submarine groundwater discharge (SGD) has attracted the interest from the scientific community over the past decade for its impact on biogeochemical cycles of coastal ecosystems and/or management of water re- sources. SGD is associated with a flow of natural radionuclides (Ra isotopes and 222Rn), which are often used as SGD tracers that can significantly increase the natural background radiation. Although in many cir- cumstances the discharge is produced directly to the sea and therefore the increase of natural radioactivity levels can generally be considered negligible due to a dilution processes, the discharge into coastal wetlands (marshes, coastal lagoons or ponds), with somewhat restricted exchange with the open sea, may require a detailed study of the distribution of natural radionuclides and their effects on the coastal ecosystem. The Peníscola marsh is a Mediterranean coastal wetland where such studies may be of special interest because it is fed exclusively by groundwater, mainly discharging from a deep aquifer with high natural radioactivity content.
In the Peníscola marsh, brackish groundwater discharging through the wetland sediments is enriched in ra- dionuclides to maximum values of 2.8 and 616 kBq m−3 of 226Ra and 222Rn, respectively. These high dissolved concentrations result in high levels of 222Rn in air (up to 36 Bq m− 3) and 210Pb and 210Po dissolved in water (20 and 5.7 Bq m−3, respectively). These elevated levels of natural radionuclides in the Peníscola marsh are also responsible of the significant increase in 210Po and 210Pb contents in both fish and plants.
Intertidal beach sands were investigated for their use as indicators of metal transport in a contaminated water body, Sepetiba Bay, Rio de Janeiro, Brazil, and are proposed as an alternative and rapid screening method to determine metal pollution status of coastal areas. The results showed that, at least for Cu, Cr, Zn and Pb, beach sands can be included in the existing environmental monitoring programs for heavy metal pollution in water bodies.
Chemical treatment of uranium mine acid drainage generates sludge containing high radioactivity levels with, for example, 238U and 226Ra concentrations at about 18 and 9kBqkg−1 dry weight, respectively. Spontaneous vegetation, such as grass (Polygonum sp.), reeds (Phragmites australis), and bullrush (Typha latifolia) growing in sludge dewatering ponds concentrated uranium and uranium daughter radionuclides. However, bullrush growing in natural wetlands by the stream receiving treated mine water discharges contained even higher radionuclide concentrations, e.g., 21Bqkg−1 dry weight of 238U, about four times higher than bullrush growing on sludge, probably because the uranium in water is more bioavailable to Typha than uranium in the chemical sludge. It is suggested that wetlands with plant species could be used as a secondary treatment to further reduce radioactivity in chemically treated uranium mine water and to improve water quality in streams receiving treated water discharges. Furthermore, it is concluded that vegetation both from sludge drying ponds and from streams receiving treated water discharges, due to the high radionuclide concentrations in the vegetation, is not suitable as cattle feeding.
Absorbed dose rates in air (dose rate) from terrestrial gamma radiations obtained using a scintillation survey meter ranged from 13.8 to 187 nGy/h depending on the geological features in Kochi Prefecture. Mean dose rates of four geological belts were found in the following order; Alluvial Deposits < Sambagawa Belt = Chichibu Belt < Shimanto Belt. The mean dose rate of the prefecture was about 60 nGy/h, which was 20% higher than that of Japan as a whole. The mean effective dose rate per person in this prefecture was about 0.37 mSv/y, which was the same as the Japanese mean. The ratio of the mean dose rates of 40K, nuclides of the thorium series and the uranium series in the soil determined using a germanium detector were 2 : 2 : 1. The relationship between 40K, 208Tl and 214Bi was positive, and therefore 40K, nuclides of the thorium series and the uranium series were considered to have the same behavior in the soil. 137Cs in the soil ranged from 1.4 to 150 Bq/kg with a mean of 24.5 ± 23.1 (S.D.) Bq/kg, suggesting that we continue to be under the influence of nuclear tests in the atmosphere.
This paper presents a table of abundances of the elements in the various major units of the Earth's lithic crust with a documentation of the sources and a discussion of the choice of units and data.
Soils and porewater of the rhizosphere of mangrove trees Rhizophora mangle and Avicennia schaueriana of the salt marsh grass Spartina alterniflora and of unvegetated mud flats, were analyzed. The study was conducted in a fringe mangrove forest in Sepetiba Bay, Rio de Janeiro, Brazil. The rhizospheres differed in their biogeochemistry and redox conditions. The distribution of trace metals (Fe, Zn, Cu, Pb and Cd) varied with the major physical and chemical charactersitics. Mud flat soils presented the highest total trace metal concentrations followed by mangrove soils and Spartina soils. However, exchangeable trace metals were similar among the different soils with the exception of Avicennia soils, which due to instability of redox conditions, presented much higher exchangeable trace metals concentrations. -from Authors