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Trophic transfer, bioaccumulation, and biomagnification of non-essential hazardous heavy metals and metalloids in food chains/webs—Concepts and implications for wildlife and human health
Abstract
Heavy metals are transferred from the abiotic environment to living organisms, accumulated in biota at different trophic levels, and thus contaminate the food chains/webs. Trophic transfer, bioaccumulation, and biomagnification of hazardous heavy metals in food chains have important implications on wildlife and human health. This review article deals with different aspects of trophic transfer, bioaccumulation, and biomagnification of four most hazardous heavy metals and metalloids, that is, Cd, Pb, Hg, and As. Different terms and concepts used in relation to trophic transfer of heavy metals, such as biotransference, bioconcentration, dietary accumulation, bioaccumulation, biomagnification, biodilution, and trophodynamics, have been discussed. Equations for quantification of trophic transfer of heavy metals and calculation of different metal transfer factors (MTFs) have been given. The important and controversial question of biomagnification of non-essential heavy metals in food chains has been addressed and discussed with examples from the available studies. Criteria for definition of metal biomagnification have been discussed. Soil-to-plant transfer of heavy metals is briefly discussed while bioaccumulation of these elements in different animal groups such as invertebrates, fish, amphibians and reptiles, birds, and mammals has been discussed with some examples. The last section briefly discusses harmful effects of these elements on wildlife and human health.
... Heavy metals are naturally present in coastal environments as a result of weathering processes, in addition, they are a result of anthropogenic activity like mining, shipping, tourism, and the burning of fuel for a vehicle [5]. The poor sediment's health was caused by heavy metal contamination, surface and groundwater, and food contamination which is a hazard to human health [6][7][8][9]. Therefore, knowledge about the heavy metal pollution of sediments is required to determine how governments and the scientific community should work together. ...
... To evaluate the environmental quality of the sediments of the study area, ecological indicators of heavy metal deposits were measured and obtained as shown in Table ( 8). (Igeo) contamination factor results are less than one (≤1), which indicates that the severity of heavy metal contamination in sediments ranges from unpolluted to moderately polluted according to the (EF) enrichment factor as estimated by [48] and (49) classifications. ...
... The findings of field measurements of the parameters relating to water quality (temperature, TDS, Eh, pH, and DO) are presented in Table ( 8). According to [60], One of the most important environmental factors influencing chemical and biological activities in water is the water's temperature, during the current investigation, there were no discernible regional variations in water temperature. ...
... Metallic trace elements (MTEs) constitute a significant part of environmental pollution at a global scale (Ullrich et al., 2001;Pacyna et al., 2007;Ali and Khan, 2019). MTEs can originate from natural sources, mainly volcanism and soil and rock erosion, but most of the environmental contamination originates from anthropogenic sources, especially from industry, agriculture and gas combustion (Ullrich et al., 2001;Pacyna et al., 2007;Ali and Khan, 2019). ...
... Metallic trace elements (MTEs) constitute a significant part of environmental pollution at a global scale (Ullrich et al., 2001;Pacyna et al., 2007;Ali and Khan, 2019). MTEs can originate from natural sources, mainly volcanism and soil and rock erosion, but most of the environmental contamination originates from anthropogenic sources, especially from industry, agriculture and gas combustion (Ullrich et al., 2001;Pacyna et al., 2007;Ali and Khan, 2019). In addition to their production from various and widespread human activities, MTEs can be transported by atmosphere and water, leading to an expansion of the contamination by leaching, transportation by soil particles and deposition of airborne emissions (Pacyna et al., 2007;Ullrich et al., 2001;Vareda et al., 2019). ...
... All the MTEs have a potential for toxicity at certain concentrations, still, some of them play essential roles in the physiological functions of organisms, such as copper (Cu), iron (Fe), manganese (Mn), selenium (Se) and zinc (Zn) (Grillitsch and Schiesari, 2010). In turn, cadmium (Cd), mercury (Hg), lead (Pb) do not participate in molecular or physiological processes and have detrimental effects on organisms (Grillitsch and Schiesari, 2010;Ali and Khan, 2019). These non-essential elements, Cd, Hg, Pb can bioaccumulate with increasing age in regularly polluted environments (Burger, 2008;Lavoie et al., 2013;Pain et al., 2019). ...
Metallic trace elements (MTEs) constitute a major source of chemical pollution and represent a threat to aquatic ecosystems and organisms. Important variation in contamination may exist at a local scale in relation to the environment (hydrosystem, trophic ressources) and individual traits (age, sex). Heretofore, the factors influencing MTEs exposure of freshwater reptiles in temperate regions are not fully understood. Freshwater turtles have a relatively high trophic position and a long lifespan, thus being potentially highly exposed due to bioaccumulation and bioamplification processes. We investigated MTE blood concentrations from two populations of the European Pond Turtle Emys orbicularis in the Camargue wetland (France). These populations, monitored since 1997, differ in their habitat and exposure (irrigation versus drainage canal). In this study, we detected 7 MTEs (Cu, Fe, Hg, Mn, Pb, Se, and Zn) which levels depended on site and individual characteristics. Hg was positively related to body size and age, indicating an increase of exposure in older individuals. We found differences between males and females with the interaction with body size for Pb and Se and with age for Pb. Nitrogen and carbon stable isotopes varied only marginally between individuals and were poorly associated with MTEs concentrations, showing that trophic position might not explain MTEs contamination for these populations. At the individual level, Hg, Pb, Se blood values were repeatable over years. Further studies should concentrate on potential ecophysiological effects to such exposure, especially since we recently evidenced that these populations of E. orbicularis are highly exposed to organic contaminants, which can lead to synergistic effects.
... Mycoremediation is a bioremediation technique that utilizes the unique properties and capabilities of fungi to remove or reduce contaminants from the environment (Fig. 5). Specifically, mycoremediation focuses on harnessing the potential of fungi for the remediation of cadmium contamination in soil or water [176]. The mycoremediation potential of various fungal strains to cope with cadmium pollution. ...
... Similarly, A. fumigatus had relatively modest but significant bioleaching capability, with rates of removal of 79%. Their findings show that A. niger and A. fumigatus M3Ai can be applied to create fresh plans for ex-situ or in-situ mycoremediation to clean up soil polluted with Cadmium [176]. In the context of cadmium remediation, certain fungi have demonstrated the ability to accumulate, transform, or immobilize cadmium through the following mechanisms: ...
Understanding the sources of cadmium (Cd) is crucial for implementing effective control measures and minimizing its environmental impact. The present study was aimed to investigate the environmental impacts of cadmium sources and to evaluate potential remedial measures for cadmium contamination. The results showed that the average amount (mg/kg) of Cd in rocks was 92 (05 (Romania). The mode of occurrence of Cd is geogenic, namely oxidation of mineralized rocks, stream sediments, volcanic materials , and soil, while anthropogenic sources include commercial and industrial wastes, hospital wastes, fertilizer , construction wastes, paints, and pigments, batteries, steel works, contaminated food, and cigarettes. Exposure to cadmium can lead to a range of health issues, including gastrointestinal distress, lung and kidney cancer, mutagenic and teratogenic effects, liver dysfunction, and fragile bone deformation. The Cd contamination can be removed through various processes such as bioremediation, phytoremediation, nano-particle remediation, soil washing, electrokinetic remediation, ion exchange, and phytostabilization may remediate the Cd level up to the maximum level. The study concluded that the toxic elements, such as Cd can be effectively remediated from contaminated media using the aforementioned methods, thereby limiting the health consequences associated with cadmium. These approaches help to remediate the health risks associated with Cd exposure. In-depth research is needed to explore the Cd in the biogeochemical cycle for better geo-management.
... Mycoremediation is a bioremediation technique that utilizes the unique properties and capabilities of fungi to remove or reduce contaminants from the environment (Fig. 5). Specifically, mycoremediation focuses on harnessing the potential of fungi for the remediation of cadmium contamination in soil or water [176]. The mycoremediation potential of various fungal strains to cope with cadmium pollution. ...
... Similarly, A. fumigatus had relatively modest but significant bioleaching capability, with rates of removal of 79%. Their findings show that A. niger and A. fumigatus M3Ai can be applied to create fresh plans for ex-situ or in-situ mycoremediation to clean up soil polluted with Cadmium [176]. In the context of cadmium remediation, certain fungi have demonstrated the ability to accumulate, transform, or immobilize cadmium through the following mechanisms: ...
... Counotte et al. (2019); Pilarczyk et al. (2020); Tekeli et al. (2021)), including for heavy metals (e.g. Ali and Khan (2019); Jota Baptista et al. (2024)), in the tissues of animals at sites where there is likely to be obvious contamination of the environment by human activity, or the research is focused on animals that are sensitive to even small changes in the environment (e.g. sentinel and bioindicator animals; Amadi et al. 2022;Parmar et al. 2016). ...
... It is the main pathway of exposure to soil metal contamination for organisms (Cui et al. 2004). Plants, as primary producers, bridge metal flows between abiotic and biotic components of ecosystems (Ali and Khan 2019). Marmot diet consists mainly of plants (grasses, berries, lichens, mosses), particularly lush herbs and soft parts of plants (shoots, leaves, heads, flowers), which are easily digestible and have a high nutritional value. ...
The Dzungarian Alatau in Central Asia and the Western Carpathians in Central Europe are exposed to anthropogenic sources of pollution that are impacting high-altitude mountain systems through long-range transport of emissions. Based on analyses of the autumn faeces of two species of marmots (Marmota baibacina from the alpine habitats of Zhongar Alatau National Park, Marmota marmota latirostris from the alpine habitats of the Western Tatras), we determined the environmental load of mercury and other chemical elements. Our results show significantly higher levels of total mercury amounts (p < 0.0001) in faeces of marmots from the Western Tatras, Slovakia (mean = 0.066 µg/g dry weight; SD = 0.43), than in Zhongar Alatau National Park, Kazakhstan (mean = 0.034 µg/g dry weight; SD = 0.01), as well as sulphur and heavy metals (Ba, Mn, Mo, Zn, Cu, and Cr) that originate from anthropogenic activities. Other significant differences in levels of mineral nutrients (K, Cl, Ca, Fe) and Sr rather indicate differences in food sources reflecting environmental factors.
... than Cr (III), considering its significant cytostatic effects and carcinogenicity [63]. Cr (VI) is dangerous and harmful and lingers in the environment, accumulates in the food chain, and poses serious risks to both human and the environment and public health [4]. Specifically, it may pose a detrimental effect on an individual's health, affecting the skin, stomach, kidneys, lungs, and liver [12]. ...
... Cation adsorption is favored at pH values above the pH pzc , while anion adsorption is preferred below the pH pzc . 0.05 g of AC zm and 50 mg/L of Cr (VI) solution were utilized in batch investigations at different pH (2)(3)(4)(5)(6)(7)(8)(9)(10) to better understand the impact of pH on Cr (VI) adsorption (Fig. 5a). Adsorption efficiency decreased notably after pH 2 and continued to decline at higher pH levels. ...
This study investigates the potential of mung bean husk, an agricultural waste, as a precursor for producing activated carbon (ACzm) to remove Cr (VI) from water. ZnCl2 activation was employed to develop a mesoporous (2.30 nm) ACzm with a high surface area (1594.15 m²/g) and abundant functional groups. Batch adsorption experiments demonstrated efficient Cr (VI) removal (97.88%) under optimal conditions (pH 2, temperature 25 °C, and adsorbent dose 1 g/L). Langmuir isotherm and pseudo-second-order kinetic models accurately described the adsorption process. Thermodynamic studies confirmed the spontaneous and exothermic nature of Cr (VI) adsorption. Moreover, the AC exhibited good reusability, maintaining 87.94% removal efficiency after five cycles. This research highlights the potential of agricultural waste–derived AC as a sustainable and cost-effective solution for Cr (VI) remediation.
... The variability of Hg levels in fish, both between and within species, has been associated with factors such as size, age, trophic position and environmental conditions (Choy et al., 2009). However, significant gaps remain in understanding how these environmental and biological factors drive Hg accumulation (Choy et al., 2009;Ali & Khan, 2018;Córdoba-Tovar et al., 2022). To protect ecosystems and human health effectively, it is essential to understand how Hg levels fluctuate in fish and how variables like size, weight, age, sex, and environmental parameters such as pH, dissolved carbon, and primary productivity influence bioaccumulation (De Pinho et al., 2002;Moore et al., 2009;Dang and Wang, 2012;Clayden et al., 2013;Azevedo et al., 2019;Wu et al., 2022). ...
... For instance, prey selectivity can significantly impact both the quantity and the type of ingested T-Hg (Choy et al., 2009;Karimi et al., 2016). Different prey items and food sources may contain varying concentrations and chemical forms og Hg (Ali & Khan, 2018;Pouilly et al., 2012). Furthermore, interactions between feeding habits and trophic level can greatly modify exposure to this pollutant. ...
... The contamination of water reservoirs− particularly freshwater sources− through heavy metals is increasing because of the expansion of industries, agricultural practices and household wastes (H. Ali & Khan, 2019b). With lacking standardized management practices and pretreatment of water before the release into water bodies; this issue is becoming more severe with time (Wakejo et al., 2022). ...
The Accumulation levels of heavy metals for intestine, muscle, gill and liver tissues of two freshwater fishes Shizothorax Plagiostomus and Crossocheilus Diplocheilus were investigated. The heavy metals such as Cobalt, Zinc, Nickel and Cadmium were determined through atomic absorption spectrophotometer. The aim of current study to evaluate heavy metal concentration in different organs of two freshwater fishes. The concentration of heavy metals is lowest in gills of both species. Metals accumulated in the body of Schizothorax Plagiostomus in order of Cd >Zn >Ni >Co. Metals concentration in various organs of Schizothorax Plagiostomus was intestine> liver> muscle> gills. Whereas, the concentration of heavy metals in different organs of Crossocheilus Diplocheilus was intestine> muscles> liver and gills. Similarly, the accumulation pattern of heavy metals in the body of Crossocheilus Diplocheilus was Cd> NI> Zn> Co. The accumulation pattern of heavy metals was different in both species, while in both species Cd was highest and Co was less accumulated heavy metal. The current study has reported that the concentration of heavy metals Zn, Ni, Cd and Co are more in Schizothorax Plagiostomus as compared to Crossocheilus Diplocheilus.
... For example, hydrocarbons are toxic to several marine and terrestrial species, leading to reduced biodiversity and altered ecosystem dynamics [10]. Heavy metals can bioaccumulate in the food chain [11], posing a risk to predators including humans who consume contaminated food. Moreover, the infiltration of these pollutants into groundwater sources can lead to long-term environmental and public health concerns including carcinogenic effects and other health issues [12]. ...
The main goal of this study is to optimize the treatment of produced water (PW) using a pilot-scale advanced electrochemical oxidation unit. The electro-cell is outfitted with a boron-doped diamond BDD anode and gas diffusion (GDE) cathode. Synthetic PW was prepared in the laboratory following a protocol designed to closely replicate the characteristics of real PW. The PW used in this study had a total dissolved solids (TDS) concentration of 16,000 mg/L and a total organic carbon (TOC) concentration of 250 mg/L. The effect of various electrooxidation parameters on the reduction in TOC was investigated including pH (2–12), electric current (I) (50–200 mA/cm2), and airflow rate (0–4 NL/min). Response surface method RSM with a Box–Behnken design at a confidence level of 95 percent was employed to analyze the impact of the above factors, with TOC removal used as a response variable. The results revealed that the TOC level decreased by 84% from 250 to 40 mg/L in 4 h, current density of 200 mA/cm2, pH of 12, and airflow rate 2 (NL/min). The investigation verified the influential role of diverse operational factors in the treatment process. RSM showed that reducing the airflow rate and increasing pH levels and electric current significantly enhanced the TOC removal. The obtained results demonstrated profound TOC removal, confirming the substantial potential of treating PW using the electrochemical method.
... They can be transferred from prey to a predator and thus can spread across food webs causing potential risks to human health (Liu et al., 2019). Thus, whether essential or not, TEs can pose an environmental problem when their concentrations exceed a threshold value causing deleterious effects on marine organisms (Ali & Khan, 2019). Cobalt (Co) is one of these TEs, at high concentrations, can be toxic to plants, aquatic organisms and humans (Gal et al. 2008). ...
Cobalt (Co) is an essential element to fish and other organisms that become toxic at high concentrations. This element is emerging as a concerning pollutant in water bodies, potentially endangering the health of marine biota. The aim of this study was to investigate the short-term subcellular toxicity of cobalt in the common carp Cyprinus carpio (0, 1.13, 11.34, 22.68 and 45.37 µg/L of Co²⁺ for 72 h), with emphasis on oxidative balance (enzymatic and non-enzymatic antioxidants), fatty acid composition, Na⁺K⁺/Mg²⁺ATPases activities and histopathological changes. Co exposure increased the levels of the ferric reducing antioxidant power, hydrogen peroxide, malondialdehyde and protein carbonyl along with enzymatic and non-enzymatic antioxidant-related markers. The observed prooxidant-antioxidant imbalance in exposed fish was solidified by histological sections confirming alterations in the histomorphological structure of C. carpio gills. Results showed that increases in Co²⁺ exposure of fish altered the ATPases activities revealing changes in osmoregulation. Additionally, the analysis of fatty acids (FA) underscored shifts in the fish's fatty acid profile, which is indicative of Co²⁺ impact on C. carpio overall metabolism and immune response. Significant changes occurred in some major FA which were associated with lipid peroxidation increase and the inhibition of Na⁺K⁺ and Mg²⁺ ATPases activities. Overall, the current results suggest that the mechanism of Co²⁺ toxicity involves oxidative damage, disruption of ionic balance, cellular homeostasis and the normal physiological function of the fish gills.
... Besides their wide chemical diversity, all of them are essentially non-biodegradable substances. Therefore, they can undergo processes of bioaccumulation and biomagnification, leading to adverse effects on organisms at different levels of organisation and along the trophic chain (Ali and Khan, 2019). For instance, insecticides, herbicides, fungicides, microplastics, particulate matter, and heavy metals can deposit on flowers and/or accumulate in the soil and then be transferred to plants (Perugini et al., 2011;Sawidis et al., 2011). ...
We present a review about histological sub-lethal effects due to anthropogenic contaminants on the midgut of bees and other aculeate hymenopterans. Contaminant types, damage types, and methodology were extracted and summarized from 74 published articles, and then quantitatively analyzed. We found that the western honeybee (Apis mellifera) is by far the most widely used model. Contaminants have largely been tested under laboratory conditions, particularly insecticides and fungicides. Tissue-level damage (e.g., degradation of epithelium and of peritrophic membrane) were often detected together with cell-level damage (e.g., cell vacuolisation, karyorrhexis). Descriptive statistics and mixed models suggested that herbicides may cause a specific mix of alterations with an overall lower severity compared with other pesticides, while the combined use of light and electron microscopy seemed to detect more damage types. We claim for efforts to reduce biases in future studies on such histological effects, allowing their clearer use as markers of human activities.
... Plants, animals, and microorganisms may be exposed to pollutants in environmental media through various channels, and pollutants have adverse effects on the growth and behavior of organisms through bioaccumulation or biomagnification in the food chain/web, especially in some sites that are planned to be developed as parks, green spaces, and mining areas with high biodiversity. Heavy metals can accumulate in the muscles, feathers, liver, kidneys, and bones of birds [1,2]. Gainer et al. (2019) found that concentrations of Cd, Zn, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, and heavy metals. ...
While methodologies for health risk assessment at contaminated sites are well established, ecological risk assessment remains in its exploratory stages. To explore suitable methods for evaluating the ecological risks of soil pollution, this study selected ten protected birds as risk receptors and evaluated the ecological risks posed by lead (Pb), arsenic (As), and total petroleum hydrocarbons (TPHs) at a petrochemical-contaminated site using a tiered approach. In the first tier, the risks of pollutants in soil and water were preliminarily evaluated based on existing ecological risk screening values, environmental quality standards, etc. The results indicated that pollutants in the soil and water at certain sampling points required attention. In the second tier, the ecological risks of multi-pathway exposure were assessed using the quotient method. This study improved the traditional exposure calculation model, which relied solely on bird body weight, by incorporating an exposure frequency adjustment coefficient. This coefficient accounts for the global activity patterns of birds, including the types of their activities (overwintering, breeding, migration, etc.) on the site, the temporal patterns of their activities, and the proportion of the site area relative to their annual activity range. Due to the low exposure frequency of birds on the site, ranging from 7.8 × 10⁻¹¹ to 9.69 × 10⁻⁷, the total exposure levels of birds were relatively low and their risk quotients were below 1, indicating an acceptable level. This study demonstrates the rationality and feasibility of a tiered ecological risk assessment method based on an improved pollutant exposure model for birds, laying the foundation for developing soil pollution ecological risk assessment methodologies and standards in China and other countries while also supporting comprehensive and effective risk management and sustainable utilization of land.
... It could spread quickly from contaminated soil to vegetation. It is also seen that the trophic level of food chains further biomagnifies Cd in environments (Ali and Khan, 2019). Cereals and vegetables are the primary food sources for the world's population. ...
In recent years, increasing heavy metal contamination in environment has raised worldwide concerns. Cadmium (Cd), being a highly toxic metal, poses potential risks both to ecosystems and human health. Various researches are focusing to investigate the effects of plant growth regulators (PGRs) on mitigating Cd toxicity in plants. Gamma-aminobutyric acid (GABA) and Methyl jasmonate (MeJA) are essential PGRs which act as signalling molecules involved in various plant physiological and biochemical processes, such as plant growth and development, cell division, nitrogen metabolism, cytoplasmic streaming and photosynthesis. Recent studies have shown that GABA and MeJA could be used as exogenous substances to protect plants against Cd stress by the alleviation of growth inhibition, regulation of metal uptake and translocation, improvement of photosynthesis, mitigation of oxidative damages and the control of signal transduction in the plants. This review focuses on alleviatory activity of GABA and MeJA in plants exposed to toxic concentration of Cd and also provides deeper knowledge in plant cellular homeostasis thereby improving the plant resilience to Cd stress.
... In addition, samples of bottom sediments from the 5-cm surface layer (two samples at midchannel and two samples near the banks) were collected at each location. 10 12,6 (5,3-18,8) 9,9 (7,0-12,0) 1 -2 11 10 6,2 (4,1-11,4) 8,0 (7,0-10,0) 1 -2 P. phoxinus 1 10 4,1 (2,4-7,1) 6,9 (6,0-9,0) 1-2 2 10 2,8 (1,9-4,2) 6,6 (6,0-7,5) 1-2 3 10 2,2 (1,0-3,5) 6,0 (4,5-7,2) 1 5 10 2,7 (1,5-5,0) 6,2 (5,0-7,5) 1-2 6 10 2,7 (1,5-8,1) 6,1 (5,2-8,5) 1-2 7 10 2,2 (1,6-3,5) 6,0 (5,5-7,0) 1 9 10 3,3 (2,4-3,7) 6,5 (5,6-7,4) 1-2 10 10 4,9 (3.5-10,0) 7,3 (6,5-9,0) 1-2 11 10 2,7 (1,4-4,9) 5,8 (5,0-7,0) 1-2 12 10 5,3 (2,3-7,6) 7,6 (6,0-8,5) 1-2 ...
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The Skawinka River is a right-bank tributary of the Vistula River, which drains from a large area near Krakow, Poland. The aim of the study was to compare the concentrations of selected heavy metals in two fish species (Gobio gobio and Phoxinus phoxinus) from the Skawinka River and its tributaries, to identify the most contaminated locations, and to assess the usefulness of gudgeon and minnow as bioindicator species. Fish and bottom sediments were sampled at selected locations, and the levels of Cd, Pb, Ni, Mn, Zn and Cu in the samples were measured using AAS. The results show that minnows accumulate higher concentrations of heavy metals in their tissue than do gudgeons. The concentrations of the metals analysed in gudgeons and minnows were positively correlated with their concentrations in the bottom sediments. The study also showed a positive association between heavy metal concentrations in fish tissue and the body weight, body length, and age of the fish, which confirms that the accumulation of the metals in fish tissue increases over time. The highest concentrations of heavy metals in the bottom sediments were found mainly at the outlet of heated wastewater from the Skawina power plant. Their concentrations in fish tissue were highest in fish from the same location and, additionally, in fish from the Cedron River in Zarzyce and from the stream Piegżówka. The results confirm that the gudgeon and Eurasian minnow are useful bioindicator species for monitoring levels of heavy metals in the environment. </p
... The mobility of Cr in soil [76,77] highlights the risk of groundwater contamination, emphasizing the interconnectedness of contaminated groundwater with soil and aquatic environments. Pb is known to bio-accumulate in aquatic organisms, leading to the bio-magnification of the metal up the food chain [78][79][80]. This can result in the decline of sensitive aquatic species, disruption of food webs, and the potential for human exposure through the consumption of contaminated seafood [60,64]. ...
Nigeria, like many other regions globally, faces challenges with groundwater contamination, particularly from toxic metal(loid)s such as lead (Pb), nickel (Ni), arsenic (As), and chromium (Cr). This chapter examined the sources, impacts, and removal techniques associated with Pb, Ni, As, and Cr contamination in Nigeria’s groundwater. It explored the geological, industrial, anthropogenic, and combined sources of these contaminants, their detrimental effects on human health and the environment, and various methods employed for their removal. It also explored the relationships between contamination sources and remediation techniques specific to Nigeria, emphasizing the need for tailored solutions. The novelty lies in providing insights into the unique challenges and opportunities for managing heavy metal contamination in Nigerian groundwater systems. These toxic elements in Nigerian groundwater pose significant health and ecological risks to the human and aquatic populations due to their bioaccumulation potential; and thus, demand effective mitigation strategies. Geological and environmental factors contribute to the metal(loid)s pollution in Nigeria, impacting both shallow and deep aquifers. Tracing and tracking these pollutants in Nigerian groundwater is very crucial for understanding the contamination sources and implementing remediation strategies effectively. The remediation of these heavy metal(loid)s in Nigeria employs physicochemical, biological, and hybrid methods. Several challenges were identified and highlighted in this chapter. Understanding these issues and challenges, policymakers, researchers, and stakeholders can develop informed strategies to safeguard water resources and protect public health in the country.
... River Heavy or hazardous metals refer to trace metals that possess a density at least five times greater than that of water [1]. In general, these substances do not undergo further decomposition into less detrimental components and instead concentrate at the site of their release [2,3]. Certain heavy metals have the potential to exhibit toxicity, including but not limited to arsenic, cadmium, lead, and mercury. ...
p> The objective of this study was to evaluate the proximate composition, microbiological contamination, and levels of heavy metals in water, sediment, and four fish species (catfish ( Clarias gariepinus ), Nile tilapia ( Oreochromis niloticus ), snakehead ( Parachanna obscura ), and marine catfish ( Arius gigas )) obtained from the Oluwa River. Water, sediment, and fish samples were collected monthly in the Oluwa River over a period of three consecutive months. The proximate composition, microbial loads, and heavy metal contents of water and fish samples were assessed utilizing established protocols. The proximate composition result shows that the moisture of the fish content ranges from 7.32 to 9.24%, the crude protein ranges from 82.16 to 85.32%, crude fiber ranges from 0.29 to 2.33%, fat ranges from 0.84 to 4.73%, ash ranges from 3.38 to 6.62%, and carbohydrates range from 0.00 to 0.11%. The findings from the analysis of microbial burdens in water and fish demonstrate a statistically significant distinction ( P < 0.05) in the counts of Enterobacteriaceae and total viable counts between the chosen samples of fish and water. The average values (mg/L) of heavy metals in the water range between 0.01 ± 0.00 and 0.53 ± 0.01, with no detection of mercury or manganese. The measured values of the parameters fell within the acceptable limits set by the World Health Organization (WHO) (0.05 mg/L), except for lead, which exceeded the limits. The average concentration (mg/L) of heavy metals in sediment was above the permissible limits except for zinc, which fell within the acceptable range. The average values (mg/kg) of heavy metals range from 1.85 ± 1.15 to 31.75 ± 0.00; 0.03 ± 0.02 and 33.21 ± 0.02; 0.02 ± 0.00 and 29.57 ± 0.02; 0.01 ± 0.00 and 23.52 ± 0.02 for P. obscura , C. gariepinus , O. niloticus, and A. gigas, respectively, and were within the maximum permissible limits set by the WHO with the exception of manganese and copper. The concentrations of heavy metals identified in the Oluwa River may not present an imminent or severe risk to fish and human consumers, potentially leading to adverse health effects. </p
... Metal speciation conditions their affinity with biological ligands at the solution-organism interface, which can be predicted based on the biotic ligand model (BLM) (Campbell et al. 2002;Zhao et al. 2016). Once internalized, metals can affect cell integrity and impair organisms, with effects that can cascade along the trophic chain Ali and Khan 2019). ...
Biofilms are increasingly used as tools for biomonitoring disturbed environments, for example, in urban, agricultural, and mining contexts. In this study, we used biofilms as integrators and bioindicators of metal contamination of Lone Elm Creek, a highly contaminated stream within the Tri-State Mining District in Joplin, Missouri (USA). We sampled biofilms upstream and downstream of a mine adit and analyzed metal content (Fe, Zn, Cd and Pb), diatom assemblage composition, and the presence and severity of frustule teratologies. Physico-chemical analyses showed marked differences in nitrogen and oxygen concentrations at the first site downstream of the mine adit. Metal concentrations in the water were elevated at all sites and did not vary markedly along the upstream–downstream gradient. In addition to metallic contamination from mine tailings, legacy of past activities may represent other sources of contamination. Diatom assemblage composition differed markedly at the site immediately downstream of the mine adit compared to other sites. The presence of frustule deformities as well as their type and their severity were investigated. Ulnaria ulna, Achnantidium minutissimum, and Fragilaria austriaca were the most frequently deformed diatoms and showed the most severe abnormalities. However, the percentage of teratologies was not correlated with metal concentrations in the water or in the biofilm. Metal bioaccumulation in the biofilm as a function of metal concentration in the water fitted well to predictive models developed in previous studies, highlighting the potential of biofilms to be used as a tool to assess exposure to metal contamination.
... The pollutants affect habitats of invertebrates and vertebrates [10]. As organisms accumulate these substances at different steps through the food chain, the affected organisms suffer, and the complexity of formulating policies to deal with the drug menace includes establishing rehabilitation aims that accommodate the harmful effects of drugs [3]. ...
The emergence of such widespread pharmaceuticals as a pollutant has become one of the world's critical environmental problems that may lead to both the public's health and biodiversity deterioration. This article provides an exhaustive account of the current understanding of the environmental persistence of pharmaceutical contaminants following in-depth analysis of the additive effects of existing natural biodegradation pathways on the human health impact of these drugs. Paying special attention to biodegradation decomposing agents such as bacteria, fungi, and algae the paper estimates their ability to convert drug ingredients to compound that is eventually less toxic. Although these biologic systems contain an enormous potential for killing the unwanted pollutants, the variability in the complexity and endurance of the pharmaceutical substances overburden the degradation capabilities of these organisms thus necessitating improved biodegradation methods. Addressing the above-mentioned environmental factors, which include temperature, pH, and the occurrence of other contaminants, play a crucial role and have a direct impact that on the process of biodegradation, enhancing pollutants removal rate. To sum up, this paper enables the environmental science, microbiology and bioengineering enables creating progressively more functional and sustainable techniques of neutralizing these long-standing toxins; thus, protecting ecosystems, as well as human health.
... The amount of Li in the human body is approximately 7 mg, with a recommended daily allowance of 1 mg. Li intake through ingestion depends on its concentration in food and varies based on soil Li levels [40]. ...
Elements which are detected in small but not precisely known amounts in the living body were called “trace elements” in the past. Recent advances in analytical technologies, such as the development of atomic absorption spectrometry, have made it possible to measure these elements precisely and to determine their functions and the characteristics of their deficiency and excess states. The so-called vitamin boom has passed, and it now appears to be boom-time for trace elements. Nowadays, cases with trace element deficiencies are often encountered clinically, especially during high-calorie parenteral therapy or enteral nutrition, and congenital abnormalities of trace element metabolism have been clarified successively. Thus, knowledge of the clinical aspects of trace elements is becoming indispensable for front-line clinicians. Meanwhile, epidemiological surveys and animal studies have suggested the possibility that some trace element deficiencies are associated with a reduced anti-oxidant potential in organisms (which is believed to possibly underlie the onset of cancer and atherosclerosis), accelerated aging, developmental retardation in children, and an increased incidence of abnormal pregnancies, immunological abnormalities, and lifestyle-related diseases. Thus, from the viewpoint of prophylactic medicine, study, survey, and prophylaxis of trace elements are also attracting close attention. Some Heavy metals have bio-importance as trace elements but the biotoxic effects of many of them in human biochemistry are of great concern. Hence, there is a need for proper understanding of mechanism involved, such as the concentrations and oxidation states, which make them harmful. It is also important to know their sources, leaching processes, chemical conversions and their modes of deposition in polluting the environment, which essentially supports life. Literature sources point to the fact that these metals are released into the environment by both natural and anthropogenic means, especially mining and industrial activities, and automobile exhausts. They leach into the underground waters, moving along water pathways and eventually depositing in the aquifer, or are washed away by run-off into surface waters thereby resulting in water and subsequently soil pollution. Poisoning and toxicity in ecosystem occur frequently through exchange and co-ordination mechanisms. When ingested, they form stable biotoxic compounds, thereby mutilating their structures and hindering bioreactions of their function.
... Pollutants, particularly inorganic pollutants such as heavy metals(HMs), disrupt soil microbial community levels, enhancing resistant organisms over sensitive ones and may even induce antimicrobial resistance in microorganisms [2]. In addition, soil contaminants have cascading effects on the primary productivity of natural and agricultural ecosystems and lead to loss of biodiversity and services of soil ecosystem due to these contaminants enter the food chain and associated with a set of adverse impacts on natural ecosystems and economy [3]. The loss of biodiversity and biomass therefore leads to a decrease in organic matter and changes in nutrient inputs and cycling [4]. ...
... The presence of PTEs in soil affects the soil's pH and interferes with nutrient cycles and microbial activity, reducing soil fertility [30,31]. In addition, in contaminated soil with PTEs, the plants bioaccumulate them, which then causes risks for plant, animal, and human health through the trophic chain [32]. Plants and animals exposed to contaminated environments can experience a range of adverse health effects, from the development of abnormalities to death [31,33]. ...
Rainwater is a source of freshwater that affects the aquatic and terrestrial ecosystems, and consequently human health. Since potential toxic elements (PTEs) have been found in rainwater in Southern Europe, its quality should be evaluated. This review assesses the current knowledge of the quality of rainwater in Southern Europe concerning PTEs, as well as its impact on the environment and human health. The presence of PTEs in rainwater poses challenges and simultaneously an opportunity for innovation in environmental management, particularly in water management. Further monitoring of rainwater quality, research, and policy development are needed to ensure that rainwater remains a viable and safe water resource. The challenges of rainwater quality regarding PTEs and of rainwater harvesting as a measure of drought mitigation, as observed in Southern Europe, require investing in rainwater treatment technologies. The treatment of rainwater harvested in Southern Europe can reduce environmental and health risks posed by PTEs, while enhancing the region’s resilience to climate change and water scarcity.
... HMs can enter the food chain through agriculture, surface waters, animal feed, industrial emissions, and waste. Crops, animals, and their derived products can become contaminated due to soil, water, or air affected by these metals [18,19]. Selenium (Se) is an essential trace element that is a component of the amino acids selenocysteine and selenomethionine. ...
The state of Zacatecas (Mexico) is one of the places most affected by pollution from the mining industry. A total of 21 samples from two areas were collected (6 samples from zone A and 15 samples from zone B) to evaluate the level of radioactivity and the degree of contamination with heavy metals. The activity concentration for 238U and 232Th was within typical values but that of 226Ra exceeded the value of 60 Bq kg−1 in both areas. In some places, the concentration of 40K was higher than the world average according to UNSCEAR. The radium equivalent activity Raeq and outdoor gamma exposure dose (D) indicated that some sites presented a radiological risk for the population. The excess lifetime cancer risk (ELCR) presented a higher risk than the world average in both sampled areas. Other parameters, such as the radiation index Ri, the external risk index Hex, and the internal risk index Hin, also indicated that there was a greater risk due to radiation exposure in these areas. In the case of heavy metals, some parameters, such as the EF, the Igeo, and the CF, showed that some places in zone A and zone B were contaminated with As and Pb. However, the concentration of selenium obtained by ICP-MS in the sampled soil was higher than the average in the Earth’s crust, both in mine waste dumps and in unaltered soil, which indicated that the background concentration for selenium in these places is higher than the world average.
... Environmental Pollution xxx (xxxx) 125285 have been reported, Croatia's neighbouring countries in southeastern Europe were identified as the most critical in Europe concerning metal (oid) levels in plants (Frontasyeva et al., 2020). Metal(loid)s enter the plant by root and foliar transfer, accumulate in herbivorous and omnivorous animals, and peak in top predators (Ali and Khan, 2019;Rodríguez-Jorquera et al., 2017). European brown bears (Ursus arctos) and the Canadian population of American black bears (Ursus americanus), both large carnivores with predominantly herbivorous diets, have been shown to accumulate more metal(loid)s in their kidneys compared to sympatric large carnivore species in forest ecosystems (Crichton and Paquet, 2000;Flaten et al., 2008;Lazarus et al., 2017). ...
Inorganic elements in trace and ultra-trace quantities play a vital role in sustaining the life process at the molecular level. Some essential trace elements may become toxic and thereby raise concern if their potential uptake is excessive in human biochemistry. The toxicity mainly arises due to undesirable coordination with the metalloenzymes and metalloproteins. It is, therefore, mandatory to comprehend thoroughly those conditions and mechanisms, such as the concentrations and oxidation states, under which the elements become harmful and bio-toxic. To fundamentally sustain life, it is essential to understand the various polluting sources, leaching processes, chemical transformations, and deposition mechanisms that impact the ecosystem. Heavy metals can infiltrate the human body through ingestion of food, water, air, or through the skin. The discovery of Minamata disease still stands as the most prominent example that illustrates the complex ecological pathway of heavy metals. Toxicity of heavy metals in the soft tissues of animals or humans occurs through their unmetabolized deposition. This toxicity can lead to interference with metabolic processes, deactivation of enzymes, weakening of the antioxidant defence, oxidative stress, destruction of proteins and lipids and damage to the functioning of the kidney, brain, liver, blood composition and other important organs. Long-term exposure to the heavy metals causes several neurological diseases like Parkinson’s, Alzheimer’s and also multiple sclerosis, dystrophy and even defects in DNA lead to cancer. In order to detoxify these toxic metals from the living system, chelation therapy is required, which utilizes the administration of some suitable chelating agents to remove the toxic metal from the living body. This review discusses in detail the mechanism of metal toxicity, toxic activity in humans and detoxification of some toxic metals like arsenic, mercury, cadmium, lead, chromium and nickel.
Heavy metal pollution in aquatic systems has become a major problem on a global scale. Many heavy metals are regarded as essential nutrients that aid in fish growth and more effective feed utilization. However, when these metal concentrations rise over the maximum amount that can be tolerated, they disrupt ecological processes and jeopardize human and fish health. Fish are dangerous due to lead contamination in their body. Lead cause toxicity because they are long-lasting and non-biodegradable in the environment. This review looked at the impact of heavy metals on fish early development, growth, and reproduction. Fish embryos and larvae, as well as each developmental stage of the embryo, react to intoxication differently and varies between species. Lead poisoning has been linked to decreased gonad somatic index (GSI), fecundity, hatching rate, fertilization success, aberrant form of reproductive organs, and ultimately loss of reproduction in fish. In summary, this review aims to increase awareness of the prevention and control of aquatic environmental pollution while shedding insight on how heavy metals manipulate fish physiology, review also gives the validate concerns regarding potential impacts of deteriorating conditions of aquatic environment and their surroundings as well as impacts on fish species and from food chain it invades ecosystem dynamics.
Phytoremediation stands at the forefront of modern environmental science, offering an innovative and cost-effective solution for the remediation of heavy-metal-contaminated soils through the natural capabilities of plants. This study aims to investigate the effects of lead (Pb) and cadmium (Cd) metals on plant growth (e.g., seedling height, stem diameter, fresh and dry weight), physiological properties (e.g., tissue relative water content, tissue electrical conductivity), and biochemical parameters (e.g., chlorophyll content, superoxide dismutase (SOD), catalase (CAT), peroxidase (POD) enzyme activities) of maize compared to the control group under greenhouse conditions at the Atatürk University Plant Production Application and Research Center. The results show that plant height decreased by 20% in the lead (Pb3000) application and by 42% in the cadmium (Cd300) application compared to the control group. The highest Pb dose (Pb3000) caused a 15% weight loss compared to the control, while the highest Cd dose (Cd300) caused a weight loss of 63%. The accumulation rates of heavy metals in soil, roots, and aboveground parts of plants indicated that maize absorbed and accumulated more Cd compared to Pb.
Soil health and ecosystem stability are increasingly under risk due to the introduction of emerging inorganic pollutants (EIPs) into the environment. Emerging inorganic pollutants have complicated interactions with soil, water, biota and lack restrictions, in contrast to well-established pollutants with explicit laws. Because of their impact on cell division, nutritional imbalances, oxidative stress, and osmotic pressure change, high quantities of several inorganic contaminants may impede plant development. Along with their phytotoxic effects, these pollutants alter the shape of roots, which results in decreased biomass and stunted development. To safeguard plant life, human health, and ecosystem integrity amidst evolving industrial, technological, and environmental challenges, it is critical to understand the impacts of these factors to devise effective mitigation strategies. This review examines the diverse sources and pathways through which novel inorganic contaminants infiltrate plant systems, underscoring their insidious nature. It explores the potential of biochar as a remediation agent, emphasizing its distinctive properties and mechanisms for immobilizing pollutants. The study highlights the necessity of considering soil-plant interactions concerning newly identified inorganic contaminants, underscoring the urgency of addressing these emerging environmental concerns.
Cadmium (Cd) stress constitutes a significant issue in agricultural soil, inflicts lethal damages to plants and posing a serious risk to public health as it enters the food chain. This review addresses the cause of Cd toxicity, its numerous forms and absorption mechanism via various transporters and their detrimental impacts on plants. At high level, Cd interacts with cellular molecules leading to overproduction of reactive oxygen species. Under Cd stress, plants naturally synthesize various compatible solutes to enhance the plant’s stress tolerance and glycine betaine (GB) is one of such solutes which act as osmoprotectant in plants. The Cd causes oxidative damage to the cells, resulted in changes in morphological attributes, physiological processes etc. and it is indispensable to alleviate Cd toxicity. To mitigate the harmful impacts of Cd, plants adapt self-regulating tolerance mechanism by producing naturally occurring osmolytes and phytochelatins (PCs). Biosynthetic pathway of GB and GB-mediated tolerance mechanism via redox homeostasis, osmotic adjustment, and mechanism of compartmentalization of Cd into the vacuole, the role of genetic engineering in GB biosynthesis in crop plants through which plants can improve their stress tolerance have been discussed. Amalgamation of this strategy must be implemented in the market with synchronization of farmers into cooperatives. This will be beneficial for the improvement in soil, plant and human health alongwith the reduction of Cd toxicity in environment. Further, this strategy must be used by government and non-government agencies, which is the most economical approach to apply at the farmer level.
Microplastics (MPs) in the world ocean ranges from 0.002 to 62.50 item/m3, with a mean abundance of approximately 2.76 items/m3, with a mean size 2.50 to 2.63 mm. Plastics enter aquatic environments without treatment and undergo photodegradation, mechanical decomposition, and bacterial breakdown, which fragment them into finer particles. The potential toxic effects of these MPs on a diverse range of aquatic organisms and humans have generated global concern. MPs that are ingested by aquatic organisms can result in substantial adverse health effects, such as accumulation, impaired reproduction, disturbed functioning of gills, altered swimming behavior, immunosuppression, and bacterial dysbiosis. Various approaches have been applied for the removal of MPs; however, a nature-based mechanism is proposed, which could play a significant role in the mitigation of MPs in aquatic environments. This article provides a concise overview of the potential origins, pathways, bioavailability, trophic transfer, and effects of MPs on aquatic organisms. In addition, the review article aimed to emphasize a range of mitigation strategies, including the application of nanotechnology for MPs.
This study evaluates the environmental and human health impact of sewage sludge generated in the Indo-Gangetic region (Uttarakhand and Uttar Pradesh) used as organic fertilizer and landfill disposal. The research conducts a comprehensive risk assessment, including physicochemical and heavy metals analysis, on triplicate sludge samples obtained from 30 sewage treatment plants. The study provides both qualitative and quantitative insights into potential hazards associated with sewage sludge. The results indicate varying concentrations (mg/kg) of heavy metals in sewage sludge (expressed in mean ± SD) as determined by inductively coupled plasma mass spectrometry (ICP-MS) with the following order, zinc (966.15 mg/ kg ± 279) > chromium (851.23 mg/kg ± 3079) > cadmium (150.07 mg/kg ± 307) > copper (186.09 mg/kg ± 56.25) > arsenic (5.24 mg/kg ± 3.54) > nickel (21.97 mg/kg ± 2.13) > mercury (1.05 mg/kg ± 0.12). The metal pollution indices underscore greater non-compliance in samples from STPs of Uttar Pradesh compared to those from Uttarakhand, with 40% of samples falling into poor to particularly poor categories. Multivariate analysis of samples reveals potential pollution sources, implicating industrial effluents and agricultural runoff, with identified controlling factors being Cu (0.948, p < 0.05); Zn (0.941 p < 0.05); Pb (0.921 p < 0.05); Ni (0.806 p < 0.05); Cd (0.717, p < 0.05); and electrical conductivity (0.620, p < 0.05). Monte Carlo-based uncertainty analysis emphasizes sludge-based chromium (Cd) as the highest risk at 62.86% (p < 0.001), trailed by chromium (59.29%, p < 0.001) for target cancer risk. The study also suggests potential management options, including the application of AI-based sensors for heavy metal monitoring, exploration of improved trapping or diluting technologies, and raising public awareness about stringent rules regarding sewage sludge remediation for effective risk mitigation strategies. Graphical Abstract
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This study evaluates the environmental and human health impact of sewage sludge generated in the Indo-Gangetic region (Uttarakhand and Uttar Pradesh) used as organic fertilizer and landfill disposal. The research conducts a comprehensive risk assessment, including physicochemical and heavy metals analysis, on triplicate sludge samples obtained from 30 sewage treatment plants. The study provides both qualitative and quantitative insights into potential hazards associated with sewage sludge. The results indicate varying concentrations (mg/kg) of heavy metals in sewage sludge (expressed in mean ± SD) as determined by inductively coupled plasma mass spectrometry (ICP-MS) with the following order, zinc (966.15 mg/kg ± 279) > chromium (851.23 mg/kg ± 3079) > cadmium (150.07 mg/kg ± 307) > copper (186.09 mg/kg ± 56.25) > arsenic (5.24 mg/kg ± 3.54) > nickel (21.97 mg/kg ± 2.13) > mercury (1.05 mg/kg ± 0.12). The metal pollution indices underscore greater non-compliance in samples from STPs of Uttar Pradesh compared to those from Uttarakhand, with 40% of samples falling into poor to particularly poor categories. Multivariate analysis of samples reveals potential pollution sources, implicating industrial effluents and agricultural runoff, with identified controlling factors being Cu (0.948, p < 0.05); Zn (0.941 p < 0.05); Pb (0.921 p < 0.05); Ni (0.806 p < 0.05); Cd (0.717, p < 0.05); and electrical conductivity (0.620, p < 0.05). Monte Carlo-based uncertainty analysis emphasizes sludge-based chromium (Cd) as the highest risk at 62.86% (p < 0.001), trailed by chromium (59.29%, p < 0.001) for target cancer risk. The study also suggests potential management options, including the application of AI-based sensors for heavy metal monitoring, exploration of improved trapping or diluting technologies, and raising public awareness about stringent rules regarding sewage sludge remediation for effective risk mitigation strategies.
Graphical Abstract
Increased population growth coupled with heightened industrial processes and improved lifestyles have led to more generation of solid waste which end up in indiscriminate and unregulated dumpsites. These slid wastes are well repositories for heavy metals which can impact negatively on the ecosystem causing severe ecological damage affecting biota. In this study, soils and Chromolaena odorata collected from ten dumpsites in Kazaure town were assayed for their heavy metal content using Flame Atomic Absorption Spectrophotometer. Physicochemical parameters of the soil were also examined using standard analytical procedures. The results revealed varying concentration of the metals in the soil and plant sample. The mean concentrations (mg/kg) of the heavy metals in the soil were: 43.0±9.3>24.4±8.4>14.0±9.0>1.3±0.7, respectively while for Chromolaena odorata the mean metal concentrations (mg/kg) reveal: 36.20 ± 7.70, 21.10 ± 5.30, 11.20 ± 3.00 and 1.5 ± 0.8 for Zn, Cu, Pb and Cd, respectively. The general trend in the metal abundance in both the soil and Chromolaena odorata is: Zn>Cu>Pb>Cd. The metal level of metals in both the soil and plant is higher than the control sites and generally exceeded the WHO maximum permissible limits. The metal transfer factors were greater than unity in several sampling locations which suggest that the plant has high potential to translocate and bio accumulate the metal in its tissues. This implies higher risk concerns about the use of soils of dumpsites as manures to grow crops for consumption. Therefore regular monitoring and decontamination of the soils from the dumpsite needs to be done before using it for agricultural activities. Moreso, it is imperative that stringent waste management policies be put in place to mitigate contamination risks, and ensure resilient and secure food system
The Amazon region has faced substantial anthropogenic pressures, resulting in an increase in the presence of pesticides and heavy metals in aquatic ecosystems. This situation is primarily attributed to population growth, uncontrolled urban expansion, high deforestation rates, and the expansion of mining activities. This review assessed more than 100 papers and reports published between 1999 and 2024 describing different effects of metals (Cu, Hg, Mn, Cd, Pb, and Ni) and pesticides (herbicides, insecticides, fungicides, and parasiticides) in the water of the Amazon basin. This chapter delves into the critical issue of pesticide and heavy metal pollution in Amazon’s aquatic environments, focusing on the toxicological effects and their implications for Amazonian fish populations. We also examine the varying degrees of toxicological vulnerability among different Amazon fish species based on recent studies. Furthermore, we offer insights into the prospects of the Amazonian aquatic biota within the context of this pollution and present emerging trends and prospective developments.
Toxic heavy metal contamination in fish sources poses significant health risks, particularly in populations that rely on fish as a primary dietary component. Thus, this study aimed to assess the concentrations of cadmium (Cd) and lead (Pb) in selected tuna species and evaluate the associated health risks and cancer burdens to consumers in Ghana through a systematic review and meta-analysis of data covering the period 2015 to 2019. A Disability Adjusted Life Year (DALY) approach was used to quantify the health burden with secondary data from the Institute of Health Metrics and Evaluation (IHME). Median contaminant exposure was 1.26 × 10 ⁻⁵ mg/kg(bw)-day for Cd, and 1.04 × 10 ⁻⁴ mg/kg(bw)-day for Pb. The highest DALY was found in the elderly age group (55-89) and it ranged from 10 ⁻⁵ - 10 ⁻³ . The results indicate that in the elderly age group, stomach cancer was the most prevalent for both males and females, reflecting a significant cancer burden. For elderly males, prostate cancer was also a severe concern, contributing to the overall cancer burden, although its prevalence was lower than that of stomach cancer. In elderly females, however, pancreatic cancer was observed to have a higher prevalence compared to males, indicating gender-specific differences in cancer risk among older adults. The findings underscore the need for public health interventions to mitigate the risks of heavy metal contamination in fish.
Citation: Santoyo-Martínez, M.; Mussali-Galante, P.; Hernández-Plata, I.; Valencia-Cuevas, L.; Rodríguez, A.; Castrejón-Godínez, M.L.; Tovar-Sánchez, E. Phytoremediation Potential of Crotalaria pumila (Fabaceae) in Soils Polluted with Heavy Metals: Evidence from Field and Controlled Experiments. Plants 2024, 13, 1947. https://doi. Abstract: Phytoremediation is a useful, low-cost, and environmentally friendly alternative for the rehabilitation of heavy-metal-contaminated (HM) soils. This technology takes advantage of the ability of certain plant species to accumulate HMs in their tissues. Crotalaria pumila is a herbaceous plant with a wide geographical distribution that grows naturally in environments polluted with HMs. In this work, the bioaccumulation capacity of roots and leaves in relation to five HMs (Cr, Cu, Fe, Pb, and Zn) was evaluated, as well as the morphological changes presented in C. pumila growing in control substrate (without HMs) and mine-tailing substrate (with HMs) under greenhouse conditions for 150 days. Four metals with the following concentration pattern were detected in both tissues and substrates: Fe > Pb > Cu > Zn. Fe, Pb, and Zn concentrations were significantly higher in the roots and leaves of individuals growing on mine-tailing substrate compared to the control substrate. In contrast, Cu concentration increased over time in the exposed individuals. The bioconcentration factor showed a similar pattern in root and leaf: Cu > Fe > Pb > Zn. Around 87.5% of the morphological characters evaluated in this species decreased significantly in individuals exposed to HMs. The bioconcentration factor shows that C. pumila is efficient at absorbing Cu, Fe, and Pb from the mine-tailing substrate, in the root and leaf tissue, and the translocation factor shows its efficiency in translocating Cu from the roots to the leaves. Therefore, C. pumila may be considered as a HM accumulator plant with potential for phytoremediation of polluted soils with Cu, Pb, and Fe, along with the ability to establish itself naturally in contaminated environments, without affecting its germination rates. Also, it exhibits wide geographical distribution, it has a short life cycle, exhibits rapid growth, and can retain the mine-tailing substrate, extracting HMs in a short time.
he present study aimed to determine the concentration of heavy metals (lead, cadmium and nickel) in the external and internal body tissues of house sparrow (Passer domesticus) living in Tehran, Iran, as a biological monitoring and also to identify possible sources of these pollutants. One of the challenges of this research was sampling and determining the population of city sparrows. The concentration of these heavy metals (in mg/kg) was measured in feather, muscle, blood, adipose tissue and diet samples of birds collected by systematic sampling (n = 96) from selected parks in the north, south, west and east of the city using inductively coupled plasma optical emission spectroscopy (ICP-OES) under optimal measurement conditions. Based on the results, the unwashed feather samples showed the highest concentration for cadmium, as Cd (449.23)> Ni (4.12)> Pb (3.67), and the washed feather samples indicated that the highest concentration of cadmium in the northern (456.75) and southern (449.23) regions. The concentration of lead in most of the regions had relatively similar values, but it was higher in the northern (5.11) and southern (3.67) regions. The highest concentration of nickel was related to the eastern (29.76) and western (9.76) regions. The comparison of our results reveals the correlation between the concentration of heavy metals studied in different tissues of house sparrows and the distribution of polluting sources in Tehran in terms of traffic load, the establishment of gas stations and industrial pollution transfer routes.To conclude, house sparrow can be used as a suitable biological indicator in determining the distribution of changes in the concentration of some heavy metals.
Traditional gold mining contributes significantly to soil mercury pollution. Stabilization/Solidification (S/S) Technology offers a remediation solution for soils contaminated with heavy metals. Besides the low cost of the technology, the S/S technology can be carried out in situ and ex-situ with material pozzolanic properties, such as Portland cement and fly ash, effectively bind these metals. This study aims to identify the proportion of mercury-contaminated soil mixed with a combination of Portland cement and fly ash. Artificial soil samples with a mercury content of 150 mg/kg were used, and test specimens were formed into 5 cm cubes. In the first phase, different ratios of Portland cement to fly ash were tested: 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50. The second phase focused on the optimal mix ratio based on compressive strength tests for combinations of Portland cement and fly ash with mercury-contaminated soil, with the same ratios as in the first phase. Subsequent compressive strength and specimens were tested using the Toxicity Characteristic Leaching Procedure (TCLP). The first phase identified the optimal 50:50 ratio of Portland cement to fly ash, achieving a compressive strength of 5559 tons/m ² . In the second phase, the same 80:20 ratio for the mix of Portland cement, fly ash, and mercury-contaminated soil yielded a compressive strength of 2902 tons/m ² and a TCLP result of 0.0062 mg/L. All samples met the criteria set by the United States Environmental Protection Agency (US EPA), with variations ranging from 17 MPa for residential concrete to 28 MPa and the TCLP-B quality standard. According to Regulation by Government No. 22 of 2021, the permissible concentration is 0.05 mg/L. The study concludes that increasing the proportion of soil and fly ash Included in the mixture reduces the quality of S/S products.
Lead (Pb) is an extremely toxic heavy metal pollutant pervasive in many environments with serious health consequences for humans and wildlife. Identifying organisms that can serve as biomonitors of lead contamination and models to understand mechanisms of lead tolerance is therefore an important goal. We used the Cuban brown anole lizard (Anolis sagrei) in New Orleans, USA, to investigate the consequences of variation in environmental lead exposure at the physiological and gene regulatory levels. We found that brown anole blood lead levels are associated with soil lead contamination, and that their blood lead levels are extreme. At our most contaminated site, the mean and highest individual blood lead levels were over two times higher than the next highest values reported in free-living vertebrates. However, this lead exposure did not decrease performance in whole-organism traits commonly affected by lead (balance, sprint speed, endurance). A 60-day lead dosing experiment demonstrated that the brown anole blood lead threshold for decreased whole-organism performance is actually an order of magnitude higher than the highest mean field concentration. Transcriptomic analysis of brain and liver from lizards in high and low lead sites revealed relatively minor effects of lead exposure. However, several of the differentially expressed genes function in metal ion homeostasis and oxygen carrying capacity, pointing to cellular mechanisms that may contribute to high lead tolerance. The brown anole may be the most lead-tolerant vertebrate known to date and has the potential to be a powerful model system to help us better understand how organisms cope with heavy metal exposure.
Seed priming technology (SP) is a practice (conducted prior to sowing) where seeds are treated with a wide range of seed priming agents (SPA) for a set time period followed by withdrawal. The efficacy of SP has been widely examined against various abiotic and biotic stressors with various crops in controlled field environmental conditions. Among the abiotic stressors, heavy metals and/or metalloids (HMs) are considered as a serious threat to sustainable agriculture. Compared with other stressors, the efficacy of SP in ameliorating HM-induced phytotoxicity and minimizing HMs content in edible parts are limited. However, there is a lack of a comprehensive study dedicated to HMs stress in wide range of crops. This review article employs a blend of bibliometric-based analysis (to assess global trends) followed by systematic evaluation of traditional (micronutrient, biomolecules, etc.) and nanomaterial (NMs)-based SPAs in ameliorating HMs-induced stress and accumulation in various crops. Our assessment suggests SPs as a suitable means to fill the vacuum that exists among the controlled environment and field condition, cost effective, easy remedial measure for HMs-induced stress. However, the need of in-depth (cellular and molecular level) as well as multi-location trials will definitely add to the current knowledge for development of effective HM stress resilience.
This chapter provides a comprehensive examination of the impacts of microplastics and nanoplastics on Arctic marine fauna within the context of biodiversity conservation efforts. Microplastics, defined as plastic particles smaller than 5 mm, and nanoplastics, even smaller particles at the nanometer scale, have become pervasive pollutants in the Arctic marine environment, posing significant threats to marine organisms and ecosystems. This chapter begins by elucidating the sources and pathways of microplastics and nanoplastics in the Arctic marine environment. These particles originate from various anthropogenic sources, including plastic debris fragmentation, microbeads in personal care products, and the breakdown of synthetic fibers from textiles. Despite their small size, microplastics and nanoplastics have the potential to accumulate in Arctic waters and sediments, where they persist for long periods. Next, this chapter delves into the ecological impacts of microplastics and nanoplastics on Arctic marine fauna. These particles can be ingested by a wide range of marine organisms, including zooplankton, fish, seabirds, and marine mammals. Once ingested, microplastics and nanoplastics can cause physical harm, blockages in the digestive tract, and internal injuries. Additionally, these particles can adsorb and concentrate toxic chemicals, such as persistent organic pollutants (POPs) and heavy metals, posing additional risks to marine organisms through chemical exposure and bioaccumulation. Furthermore, this chapter explores the implications of microplastic and nanoplastic pollution for biodiversity conservation efforts in the Arctic. Marine fauna in the Arctic region are integral components of complex ecosystems, and their well-being is crucial for maintaining ecosystem balance and resilience. The presence of microplastics and nanoplastics can disrupt marine food webs, alter species interactions, and degrade habitat quality, ultimately threatening the biodiversity of Arctic marine ecosystems. In light of these challenges, this chapter discusses strategies for mitigating the impacts of microplastics and nanoplastics on Arctic marine fauna and promoting biodiversity conservation. These strategies may include measures to reduce plastic consumption, improve waste management practices, enhance recycling efforts, and promote the use of biodegradable alternatives to conventional plastics. Additionally, this chapter emphasizes the importance of interdisciplinary research, monitoring programs, and public awareness campaigns to address the complex issues surrounding microplastic and nanoplastic pollution in the Arctic marine environment. By shedding light on the impacts of microplastics and nanoplastics on Arctic marine fauna within the context of biodiversity conservation efforts, this chapter aims to raise awareness, inform policymaking, and mobilize action to protect the delicate ecosystems of the Arctic and preserve the rich biodiversity they support. Through collaborative efforts and concerted action, we can strive toward a future where Arctic marine fauna thrive in a clean and healthy environment.
The hazardous nature of heavy metals (HMs) in the ecosystem has drawn global attention due to its emergence as a major environmental and public health concern. As toxic metals are non-degradable, they affect not only animals but also human beings and vegetation. These HMs are long-lasting pollutants that travel vast distances from their site of origin in the environment and bioaccumulate in humans and other organisms through the food chain. These pollutants can cause extensive pollution since they are frequently produced by industrial activities and inappropriate disposal procedures. Biosurfactants’ (BSs) versatility makes them an appealing category that plays an essential role in various biotechnological applications for environmental remediation. BSs have a variety of characteristics, including metal binding, solubilization, and emulsification. They remediate the HMs through processes like complexation, ion exchange, and metal solubilization. Furthermore, owing to their amphiphilic nature, they improve the sorption and solubility of hydrophobic contaminants and reduce the surface area and interfacial tension of immiscible liquids. As a result, BS-based remediation plays an important part in the heavy metal removal process in multiple ways. This review aims to provide information on the function of BSs in eliminating HMs through bioremediation processes for environmental sustainability.
Contamination of freshwater fish with toxic heavy metals and metalloids is a major environmental issue in terms of public health. For instance, Cd, Pb, Hg and As are biologically non-essential elements with known adverse effects. Consumption of fish contaminated with metals thus poses a risk to human health. Here we review the bioaccumulation of Cd, Pb, Hg and As in freshwater fish, and we discuss the associated risk to human health. We present possible routes for uptake of heavy metals and metalloids in fish. Various factors affect bioaccumulation in fish, such as fish feeding guilds. We also present various indices used to assess risk to human health, such as metal pollution index, health risk index, target hazard quotient and hazard index.
The term ‘heavy metals’ is commonly used in the environmental literature to refer to metals and metalloids associated with environmental pollution, toxicity and adverse effects on biota. The term has been diversely defined, mostly in terms of density, relative atomic mass and atomic number. This diversity of definitions has raised questions about the nomenclature of these elements. The inclusion of the metalloid As and the nonmetal Se with heavy metals is also an important issue. Some people have called the term as meaningless, imprecise and poorly defined and have suggested abandoning the use of the term. The term itself may not be problematic but the careless and inconsistent use of terminology has led to a confusion about the meaning of the term. The use of the term may be continued but it should be defined in a more comprehensive and scientific way. Here a more comprehensive definition of the term ‘heavy metals’ is suggested as ‘naturally occurring metals having atomic number (Z) greater than 20 and an elemental density greater than 5 g cm−3.’ A screening of the Periodic Table according to this definition yields 51 elements to be called ‘heavy metals.’ As and Se are excluded from heavy metals.
Heavy metals and some organic substances which are drained into the aquatic environments and cannot be decomposed or eliminated will sink into sediments or find their way into different levels of food chain. Bioaccumulation is the process of continuous deposition and aggregation of these substances into the body tissue of living organisms. Mollusks are remarkably appropriate to be used as bio-indicators because of their motionless or almost sessile nature, relatively high abundance, selective absorption of certain ions, and worldwide distribution in marine and inland aquatic habitats. Chiton lamyi is a sedentary species from the phylum, Polyplacophora, which is usually abundant on the rocky shores and intertidal zone of marine environments. Sediment and Chiton samples were taken from four stations of Chabahar Bay in autumn 2013. After acid digestion of samples, the concentration of heavy metals (mercury, cadmium, arsenic, nickel, lead and copper) were measured by the graphite furnace atomic absorption apparatus, and the bioaccumulation factor in relation to sediment was calculated. The highest concentration value was calculated as 3.28 for cadmium in the Hafte Tir station. The results of this study indicated that chitons can be used as an appropriate bio-indicator for heavy metals particularly cadmium pollution in the marine environment.
Bioindicators have been generating great interest in environmental pollution research. Insects and especially arthropod are useful to assess the effects of anthropogenic activities on the terrestrial ecosystem, because they are inclose contact with toxic elements present in soil and in leaf litter. Beetles are extremely sensitive to several ecological parameters, react quickly to environmental modifications and can be easily and cost-effectively sampled by various methods. These criteria make beetles excellent indicators of terrestrial ecosystem. In order to evaluate the environmental impact of human activities on different ecosystems, the use of Coleoptera in ecological studies has been largely increased in recent years.
This review presents the results obtained by researchers when using beetles as bioindicators of metallic pollution and forest disturbance.
Determination of metal levels in muscles and livers of twelve fish species from Aegean Sea and Mediter-ranean Sea by ICP-AES was made. The levels of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in muscles of fish were <0.01–0.39, <0.01–0.45, 0.07–1.48, 0.51–7.05, 9.18–136, 0.18–2.78, 0.03–1.72, 0.21–1.28 and 3.51– 53.5 mg kg À1 , respectively. Metal levels in muscles were generally lower than those in livers. Metal concentrations in the edible parts of fish were assessed for human uses according to provisional tolerable weekly intake (PTWI) and provisional tolerable daily intake (PTDI). The estimated values of all metals in muscles of fish in this study were below the established values. Therefore, it can be concluded that these metals in edible parts of the examined species should pose no health problems for consumers.
Contamination of aquatic ecosystems with heavy metals leads to accumulation of these elements in aquatic biota including fish. Bioaccumulation of heavy metals in fish is of public health concern because fish are an important part of human diet. The present study was conducted to investigate the bioaccumulation of two heavy metals, Cu and Zn, in muscles of two economically important fish species, an herbivorous fish Schizothorax plagiostomus and a predatory fish Mastacembelus armatus, from three rivers of Malakand Division, Pakistan. Concentrations of Cu and Zn were determined in fish samples by atomic absorption spectrophotometer. Highest Cu concentration of 4.52 ± 0.24 mg kg⁻¹ wet weight was observed in muscles of M. armatus at Chakdara on River Swat while highest Zn concentration of 18.00 ± 1.88 mg kg⁻¹ wet weight was observed in muscles of S. plagiostomus at Daggar on River Barandu. A site wise comparison of both Cu and Zn concentrations in muscles of the study fish generally showed no significant differences among different sites on the rivers. However, in some cases, metal concentrations showed significant increase down the stream. Similarly, a comparison of metal concentrations in muscles of the two species generally did not show significant differences between the two species. Zn concentrations in fish muscles were higher than Cu concentrations in all cases. Bioaccumulation factor (BAF) values for Cu were in the order of kidneys > muscles > liver > gills > skin while for Zn the order was skin > kidneys > liver > gills > muscles.
Mercury (Hg) is a highly toxic metal that has detrimental effects on wildlife. We surveyed Hg concentrations in 10 species of bats collected at wind farms in the central United States and found contamination in all species. Mercury concentration in fur was highly variable both within and between species (range 1.08-10.52 μg/g). Despite the distance between sites (up to 1200 km), only 2 of the 5 species sampled at multiple locations had fur Hg concentrations that differed between sites. Mercury concentrations observed in the present study all fell within the previously reported ranges for bats collected from the northeastern United States and Canada, although many of the bats we sampled had lower maximum Hg concentrations. Juvenile bats had lower concentrations of Hg in fur compared to adult bats, and we found no significant effect of sex on Hg concentrations in fur. For a subset of 2 species, we also measured Hg concentration in muscle tissue; concentrations were much higher in fur than in muscle and Hg concentrations in the 2 tissue types were weakly correlated. Abundant wind farms and ongoing post-construction fatality surveys offer an underutilized opportunity to obtain tissue samples that can be used to assess Hg contamination in bats. This article is protected by copyright. All rights reserved.
Mercury (Hg) is a ubiquitous environmental contaminant that affects avian reproduction and condition, in both aquatic and terrestrial species. Because Hg binds strongly to the keratin of growing feathers, molt is an important avenue for Hg elimination. We investigated the rate of depuration of Hg from songbird blood and organs (brain, kidney, liver, muscle) as a function of molt. We exposed 2 species of captive songbirds, European starling (Sturnus vulgaris) and zebra finch (Taeniopygia guttata), to environmentally relevant dietary Hg (1.2-1.5 mg/kg wet wt) for extended periods of time and then allowed them to depurate on a Hg-free diet for 20 wk. Depuration occurred either while birds were regrowing new feathers or when there was little to no molt occurring. Both species quickly eliminated Hg from blood and reduced Hg concentrations in other tissues by more than 90% over 20 wk. The rate of depuration was more rapid than previously reported in the literature, but depuration in small-bodied songbirds has rarely been studied. Molting birds depurated Hg from their blood more rapidly than nonmolting birds. The effect of molt on Hg retention in other tissues was more difficult to resolve, because by the time we sampled organ tissue, depuration was nearly complete. Our results confirm that molting expedites depuration and raises mechanistic questions about how songbirds depurate Hg stored in their tissues. Environ Toxicol Chem 2017;9999:1-7. © 2017 SETAC.
Chaohu Lake is the fifth largest freshwater lake in China, which tolerates substantial amount of anthropogenic discharge from surrounding cities that resulting in the degradation of water and damage of aquatic ecosystem. Metal analysis of sediment and aquatic organisms can provide important information on the environmental contamination and potential impact of aquatic food consumption. Thus, the concentrations of Cu, Pb, Zn, Cr, Cd, As, and Hg in sediment and fish from Chaohu Lake were analyzed with inductively coupled plasma mass spectrometry and atomic fluorescence spectrometry. The mean content of Cu, Pb, Zn, Cr, Cd, As, and Hg in the sediment samples were 27.4 ± 6.3, 40.5 ± 12.3, 136.8 ± 65.5, 68.5 ± 9.1, 0.357 ± 0.141, 10.8 ± 1.7, and 0.117 ± 0.049 mg/kg, respectively. The results were compared with background values and evaluation methods, to characterize the potential ecological risk. The concentrations of Cu, Pb, Zn, Cr, Cd, As, and Hg in the fish muscle samples were 1.68-5.31, 0.078-0.31, 15.55-372.98, 0.31-0.93, 0.001-0.033, 0.29-1.03, and 0.04-0.197 mg kg(-1) of dry mass, respectively. Most of the concentrations of the studied metals in muscles were found to be below the safe limits; however, the concentration of inorganic As (10% of total As) in two specimens exceeded the maximum allowance in fish. The ecological risk evaluation showed that the metals in sediment posed low to medium risk. The health risk assessment suggested that the consumption of fish from Chaohu Lake is currently safe with respect to the metals.
Heavy metals in the environment may be toxic for human and animals. Tanneries are a source of pollution by heavy metals. There is little information on heavy metals pollution in tanneries, especially on metals produced by the process of hair burning and liming. Liming is the first stage of chemical treatment where animal hair or wool is removed with sodium sulphide and calcium oxide. Here we studied cow, goat, buffalo and sheep hair, conventional liming agents and liming wastewaters from several sources. Samples were acid-digested and aliquots were analysed by atomic absorption spectroscopy following APHA standard method to measure concentrations of arsenic, lead, cadmium, zinc, manganese and iron. Results show that the range of metal contents in hair or wool and liming agents are 1.3–8.2 mg/kg for arsenic, 0.02–21.8 mg/kg for lead, 17.7–121.0 mg/kg for manganese, 7.3–141.1 mg/kg for zinc and 119.6–10613.8 mg/kg for iron. Liming wastewaters contain 1.9–5.6 µg/L arsenic, 0.03–6.05 µg/L lead, 38.6–139.0 µg/L manganese, 144.0–171.5 µg/L zinc and 399.5–1069.0 µg/L iron. Cadmium was below detection limits. This is the first investigation that reveals that hair burning liming operation is a potential source of heavy metals in the environment.
The health risks arising from heavy metal pollution (HMP) in agricultural soils have attracted global attention, and research on the accumulation of heavy metals in soil-plant systems is the basis for human health risk assessments. This review studied the accumulation of seven typical heavy metals-Cd, Cr, As, Pb, Hg, Cu, and Zn-in soil-corn and soil-wheat systems. The findings indicated that, in general, wheat was more likely to accumulate heavy metals than corn. Bioconcentration factor (BCF) of the seven heavy metals in wheat and corn grains decreased exponentially with their average concentrations in soil. The seven heavy metals were ranked as follows, in ascending order of accumulation in corn grains: Pb < Cr < Zn < As < Cu < Cd <Hg. As for the order of accumulation in wheat grains, their ranking was as follows: Zn < Pb < Cr < Cu < As < Hg <Cd. The minimum BCFs of Cd, Cr, As, Pb, Hg, Cu, and Zn in corn grains were 0.054, 6.65 × 10(-4), 7.94 × 10(-4), 0.0044, 0.028, 0.13, and 0.19, respectively. The corresponding BCFs values for wheat grains were 0.25, 0.0045, 5.42 × 10(-4), 0.009, 4.03 × 10(-4), 0.11, and 0.054, respectively.
Routine monitoring of contaminant levels in wildlife is important for understanding chemical exposure and ultimately the link to ecosystem and human health. This is particularly important when the monitored species is recreationally hunted for human consumption. In the southeastern United States, recreational alligator harvesting takes place annually and in locations that are known to be contaminated with environmental pollutants. In this study, we investigated the biodistribution of trace elements in the American alligator (Alligator mississippiensis) from five sites in Florida, USA. These sites are locations where annual recreational alligator harvesting is permitted and two of the sites are identified as having high mercury contamination with human consumption advisories in effect. We utilized routinely collected monitoring samples (blood and scute), a commonly consumed tissue (muscle), and a classically analyzed tissue for environmental contaminants (liver) to demonstrate how the trace elements were distributed within the American alligator. We describe elemental tissue compartmentalization in an apex predator and investigate if noninvasive samples (blood and scute) can be used to estimate muscle tissue concentrations for a subset of elements measured. We found significant correlations for Hg, Rb, Se, Zn and Pb between noninvasive samples and consumed tissue and also found that Hg was the only trace metal of concern for this population of alligators. This study fills a gap in trace elemental analysis for reptilian apex predators in contaminated environments. Additionally, comprehensive elemental analysis of routinely collected samples can inform biomonitoring efforts and consumption advisories.
Study was carried out to investigate the genotoxic effect of different levels of heavy metals on gill cells of freshwater mussels (Anodonta anatina), a sentinel species in aquatic environment. Freshwater mussels were exposed to none (0µg L-1), low (120 µg L-1), medium (240 µg L-1) and high (360 µg L-1) levels of lead (Pb), chromium (Cr) and copper (Cu) alone and in combinations (Pb + Cr + Cu) for 15 days under laboratory conditions. Gill cells of mussels were used to determine the DNA damage by comet assay. The tail DNA (%), comet tail length and olive tail moment (OTM) were the parameters selected to detect DNA damage. Low doses (120 µg L-1) of each metal induced significantly higher levels of DNA strands breaks as compared to medium dose (240 µg L-1) and very low levels of DNA damaged was observed at high dose (360 µg L-1). Cu and Pb showed significantly higher value of % of tail DNA (56.74±1.81, 47.36±1.23) and comet tail length (41.30±0.758, 49.15±1.90), respectively, as compared to Cr and combined metal exposure (Pb + Cu + Cr). The lowest levels of DNA damage for all the parameters were observed in combined metal treatment. Genotoxic effect of metals on freshwater mussels is very important to assess the aquatic health and could be suggested as biomarker. It is concluded that the Cu and Pb induced more DNA damage as compared to Cr and combined metal exposure (Pb + Cu + Cr). Moreover, our results showed that the low dose treatment of metals have more genotoxic effect as compared to the medium and high doses.
Arsenic (As) is found in waters such as seawater, warm springs, groundwater, rivers, and lakes. In aquatic environments, As occurs as a mixture of arsenate and arsenite, with arsenate usually predominating. The unrestricted application of As pesticides, industrial activities, and mining operations has led to the global occurrence of soluble As above permissible levels of 0.010 mg/L. Continuous exposure of freshwater organisms including fish to low concentrations of As results in bioaccumulation, notably in liver and kidney. As a consequence As induces hyperglycemia, depletion of enzymatic activities, various acute and chronic toxicity, and immune system dysfunction. Here we review arsenic chemistry, the occurrence of arsenic in aquatic system, the transformation and metabolism of arsenic; arsenic bioaccumulation and bioconcentration; behavioral changes; and acute and other effects such as biochemical, immunotoxic, and cytogenotoxic effects on fish.
The current study investigated metal concentrations (Zn, Cd, Pb, Mn and Fe) in the habitat and body tissues (blood, liver and kidney) of common skittering frog Euphlyctis cyanophlyctis along the Korang River, Islamabad, Pakistan. Samples were collected from three selected contaminated sites and a reference site at four different occasions from October 2010 to March 2012. All studied metals showed elevated levels in river water, as well as in blood, liver and kidneys of frogs from all contaminated sites. Specifically, Mn showed significantly higher levels in all analysed matrices from contaminated sites compared to the reference site. Histological sections of frog livers exposed to elevated metals showed abnormal hepatocytes, while their kidney sections showed discontinuous glomeruli with dead or ruptured cells exhibiting improper shapes with cytoplasmic depositions. This study indicates that frogs inhabiting Korang River are at potential risk of metal toxicity from the environment. © 2016, Asociacion Herpetologica Espanola. All rights reserved.
In the developing world, vegetables are commonly grown in suburban areas irrigated with untreated wastewater containing potentially harmful elements (PHEs). In Pakistan, there is no published work on the bioaccessibility aspect of PHEs and dietary minerals (DMs) in sewage-irrigated soil or the vegetables grown on such soils in Pakistan. Several industrial districts of Pakistan were selected for assessment of the risk associated with the ingestion of vegetables grown over sewage-irrigated soils. Both the total and bioaccessible fraction of PHEs (Cd, Co, Cr, Ni, and Pb) and DMs (Fe, Cu, Mn, Zn, Ca, Mg, and I) in soils and vegetable samples were measured. The concentrations of these PHEs and DMs in sewage-irrigated and control soils were below published upper threshold limits. However, compared to control soils, sewage irrigation over the years decreased soil pH (7.7 vs 8.1) and enhanced dissolved organic carbon (1.8 vs 0.8 %), which could enhance the phyto-availability of PHEs and DMs to crops. Of the PHEs and DMs, the highest transfer factor (soil to plant) was noted for Cd and Ca, respectively. Concentrations of PHEs in most of the sewage-irrigated vegetables were below the published upper threshold limits, except for Cd in the fruiting portion of eggplant and bell pepper (0.06–0.08 mg/kg Cd, dry weight) at three locations in Gujarat and Kasur districts. The bioaccessible fraction of PHEs can reduce the context of dietary intake measurements compared to total concentrations, but differences between both measurements were not significant for Cd. Since the soils of the sampled districts are not overly contaminated compared to control sites, vegetables grown over sewage-irrigated soils would provide an opportunity to harvest mineral-rich vegetables potentially providing consumers 62, 60, 12, 104, and 63 % higher dietary intake of Cu, Mn, Zn, Ca, and Mg, respectively. Based on Fe and vanadium correlations in vegetables, it is inferred that a significant proportion of total dietary Fe intake could be contributed by soil particles adhered to the consumable portion of vegetables. Faecal sterol ratios were used to identify and distinguish the source of faecal contamination in soils from Gujranwala, Gujarat, and Lahore districts, confirming the presence of human-derived sewage biomarkers at different stages of environmental alteration. A strong correlation of some metals with soil organic matter concentration was observed, but none with sewage biomarkers.
Exposure of heavy metals to humans is higher today than ever before in modern history due to continuously increasing industrialization around the globe. Industrial wastes are rich in heavy metals and these wastes are discharged near agricultural fields or mixed with soil, from where these metals are taken up by the crops and are finally transported to humans. Due to this increasing threat of heavy metals contamination in food, it is necessary to analyze the food before consumption. Content of selected metals (Cd, Cr, Cu, Pb and Zn) in cow milk is determined in this study. To investigate the possible pathways of these metals to reach in milk; fodder supplied to these cows was analyzed besides analysis of soil samples on which this fodder was grown. Pearson correlation among metal contents in soil-forage and forage-milk was also determined to check the route of transfer of these metals from soil to forage and from forage to milk. It was found that a strong correlation (p < 0.5) exists for Cr, Cd, Cu and Zn. This shows that these metals are mainly transferred through soil. However, a weak correlation was found for Pb, which shows that Pb is introduced into forage through some other source (automobile exhaust etc.). A comparison of present study is also done with previously reported work from other countries on metal contents in milk and findings of both the studies were in good agreement mutually.
This study is aimed to assess the heavy metals contamination and health risk in Shrimp (Macrobrachium rosenbergii and Penaeus monodon) collected from Khulna-Satkhira region in Bangladesh. The results showed that the Pb concentrations (0.52–1.16mg/kg) in all shrimp samples of farms were higher than the recommended limit. The Cd levels (0.05–0.13mg/kg) in all samples and Cr levels in all farms except tissue content at Satkhira farm were higher than the permissible limits. The individual concentration of Pb, Cd, and Cr between shrimp tissue and shell in all rivers and farms were not statistically significant (P>0.05). Target hazard quotient (THQ) and hazard index (HI) were estimated to assess the non-carcinogenic health risks. Shrimp samples from all locations under the current study were found to be safe for consumption, the possibility of health risk associated with non-carcinogenic effect is very low for continuous consumption for 30 years.
The numbers of chemicals which are the most important group of environmental pollution were limited to a few thousand until the beginning of this century. But nowadays, due to intensive production and the unconscious usage, the chemical pollution is increasing throughout the food chain and is damaging all living creatures. The chemical levels of the water, the sediment and the aquatic organisms are very important to determine the level of the chemical contamination of the marine environments by biological. The aquatic organisms, such as fish, crustaceans, algae, protozoa, macrophytes, bacteria and plankton are widely used as a biomarker in determining the quality of aquatic systems for the environmental contaminants. Because of this importance the description and differences of marine pollution terms are significant. In this review, the data were collected from different literatures around the World in uses terms of monitoring the aquatic organisms for chemical pollution in aquatic system.
Wastewater irrigated fields can cause potential contamination with heavy metals to soil and groundwater, thus pose a threat to human beings . The current study was designed to investigate the potential human health risks associated with the consumption of okra vegetable crop contaminated with toxic heavy metals. The crop was grown on a soil irrigated with treated wastewater in the western region of Saudi Arabia during 2010 and 2011. The monitored heavy metals included Cd, Cr, Cu, Pb and Zn for their bioaccumulation factors to provide baseline data regarding environmental safety and the suitability of sewage irrigation in the future. The pollution load index (PLI), enrichment factor (EF) and contamination factor (CF) of these metals were calculated. The pollution load index of the studied soils indicated their level of metal contamination. The concentrations of Ni, Pb, Cd and Cr in the edible portions were above the safe limit in 90%, 28%, 83% and 63% of the samples, respectively. The heavy metals in the edible portions were as follows: Cr>Zn>Ni>Cd>Mn>Pb>Cu>Fe. The Health Risk Index (HRI) was >1 indicating a potential health risk. The EF values designated an enhanced bio-contamination compared to other reports from Saudi Arabia and other countries around the world. The results indicated a potential pathway of human exposure to slow poisoning by heavy metals due to the indirect utilization of vegetables grown on heavy metal-contaminated soil that was irrigated by contaminated water sources. The okra tested was not safe for human use, especially for direct consumption by human beings. The irrigation source was identified as the source of the soil pollution in this study.
Cd, Pb, and Zn were quantified in liver and kidney of red foxes (Vulpes vulpes) which were hunted during the 2003–2011 hunting seasons in Galicia (NW Spain). The effects of age and gender were evaluated to determine whether these variables should be included in future biomonitoring studies. The concentrations of hepatic and renal Cd (average 0.6 and 1.3 µg/g) and Pb (0.8 and 0.06 µg/g, respectively) were similar to background levels, with no known toxicological relevance. Similarly, the average levels of Zn in liver and kidney (77 and 17 µg/g) were in the range of physiological levels for canids. Although no significant gender-dependent variations were observed, the effect of aging was evident: the levels of hepatic Pb and both hepatic and renal Cd were higher in adults than in juveniles. Age should be included as a parameter during future biomonitoring programs focusing on trace metal bioaccumulation in red foxes.
In a recently published study we observed that effluents from marble industry affected physicochemical characteristics of River Barandu in District Buner, Pakistan. These changes in water quality due to marble effluents may affect fish community. The present study was therefore conducted to evaluate the impacts of marble industry effluents on fish communities in River Barandu using abundance, richness, diversity and evenness of fish species as end point criteria. The fish samples were collected by local fishermen on monthly basis from three selected sites (upstream, effluents/industrial, and downstream sites). During the study period, a total of 18 fish species were found belonging to 4 orders, 5 families and 11 genera. The Cyprinidae was observed to be the dominant family at all the three selected sites. Lower abundance and species diversity was observed at the industrial (22 %) and downstream sites (33 %) as compared to the upstream site (45 %). Effluents of marble industry were associated with lower abundance of species in River Barandu. It is recommended that industries should be shifted away from the vicinity of river and their effluents must be treated before discharging to prevent further loss of fish abundance and diversity in the River.
Concentrations of 10 heavy metals (Cu, Zn, Cd, Pb, Fe, Mn, Cr, Se, As, and Hg) were determined in different organ tissues of four selected common red sea fish species viz., Lethrinus nebulosus, Cetoscarus pulchellus, Plectorhynchus schotaf and Epinephelus spp. There was a highly significant (P< 0.01) difference among the 4 fish species and between organs for the accumulation of all 10 metals. The concentration of Fe was highest closely followed by Zn, whereas Cd was detected in the lowest concentration. The liver accumulated the highest concentration of metals and muscles had the concentration of all studied metals. It has been observed that Lethrinus nebulosus species accumulated the highest concentration of total analyzed elements in this study, which indicate that this species have more potential to accumulate all of metals in each tissue.
The contamination of heavy metals, such as chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), cadmium (Cd) and lead (Pb) were evaluated in the water and tissues of African catfish Clarias gariepinus and Sabaki tilapia Oreochromis spilurus from Wadi Hanifah, Riyadh. The samples were collected from three sampling sites (Namar, Al-Masani and Al-Hair) of Wadi Valley of central Saudi Arabia during May-June 2013. The water and fish samples collected from Al-Masani, nearby a vehicle mechanical industrial area, were found to be more contaminated by Cr, Fe, Zn and Pb than those of other sampling sites. The high concentrations of Fe were detected in all the water and fish samples, followed by Zn, Pb, Cr, Co, Ni and Cd. However, none of the detected HM (heavy metals) concentrations were exceeded the permissible limits set by the different authorities. The estimated daily intake was found to be below the provisional tolerable daily intake (PTDI), established by the FAO and WHO, indicating that there was no carcinogenic risk for humans.
Heavy metal contamination is a globally recognized environmental issue, threatening human life very seriously. Increasing population and high demand for food resulted in release of various contaminants into environment that finally contaminate the food chain. Edible plants are the major source of diet, and their contamination with toxic metals may result in catastrophic health hazards. Heavy metals affect the human health directly and/or indirectly; one of the indirect effects is the change in plant nutritional values. Previously, a number of review papers have been published on different aspects of heavy metal contamination. However, no related information is available about the effects of heavy metals on the nutritional status of food plants. This review paper is focused upon heavy metal sources, accumulation, transfer, health risk, and effects on protein, amino acids, carbohydrates, fats, and vitamins in plants. The literature about heavy metals in food plants shows that both leafy and nonleafy vegetables are good accumulators of heavy metals. In nonleafy vegetables, the bioaccumulation pattern was leaf > root ≈ stem > tuber. Heavy metals have strong influence on nutritional values; therefore, plants grown on metal-contaminated soil were nutrient deficient and consumption of such vegetables may lead to nutritional deficiency in the population particularly living in developing countries which are already facing the malnutrition problems.
To study the accumulation and contamination of heavy metals (i.e., Cd, Cr, Cu, Ni, and Zn) in soil, air, and water, few insect species were assayed as ecological indicators. Study area comes under industrial zone of district Gujrat of Punjab, Pakistan. Insects used as bioindicators included a libellulid dragonfly (Crocothemis servilia), an acridid grasshopper (Oxya hyla hyla), and a nymphalid butterfly (Danaus chrysippus) near industrial zone of Gujrat. Accumulation of Cd was highest in insect species followed by Cu, Cr, Zn, and Ni at í µí± < 0.05. Hierarchical cluster analysis (HACA) was carried out to study metal accumulation level in all insects. Correlation and regression analysis confirmed HACA observations and declared concentration of heavy metals above permissible limits. Metal concentrations in insects were significantly higher near industries and nallahs in Gujrat and relatively higher concentrations of metals were found in Orthoptera than Odonata and Lepidoptera. The total metal concentrations in insects were pointed significantly higher at sites S3 (Mid of HalsiNala), S9 (End of HalsiNala), and S1 (Start of HalsiNala), whereas lowest value was detected at site S6 (Kalra Khasa) located far from industrial area. HACA indicates that these insect groups are potential indicators of metal contamination and can be used in biomonitoring.
An assessment of the dietary risk of heavy metal exposure to humans is important since it is the main source of exposure. This study aimed to estimate the degree of contamination and assess the probable health risk in the prawn food chain. In prawn feed, the concentrations of metals were detected in the following order: Hg > Co > Pb > Cd. The concentrations of heavy metals in prawn were the highest for Co and lowest for Cd. Trace amounts of As and Cr were detected in the analyzed sample. Target hazard quotients for heavy metals for adults were >1 for Pb, Cd, Hg, and Co, and for children, the same were high for Co and Hg, indicating significant health risks upon dietary exposure. All the prawn samples contained nine-fold and fourteen-fold higher concentrations than the maximum acceptable levels for Pb and Hg, respectively (0.5 mg kg−1; WHO/FAO). Human health risk due to the Co exposure is quite alarming as the level of exposure was found to be very high. In the prawn samples intended for human consumption, the hazard index (HI) was highest in the samples obtained from Bagerhat (3.25 in flesh and 3.26 in skin), followed by the samples obtained from Satkhira (2.84 in flesh and 3.10 in skin) and Dhaka City Corporation (2.81 in flesh and 3.42 in Skin); this indicates a potential risk of prawn consumption obtained from Southeast Bangladesh. This is particularly problematic as this area accounts for the majority of prawn production and export of the country.
Contamination of freshwater bodies and consequently freshwater fish with toxic heavy metals is a serious environmental issue. The trophic transfer of potentially toxic heavy metals in the human food chains, especially in fish has important implications for human health. The present research study was designed to assess the concentrations of the heavy metals Cr, Ni, Cd, and Pb in the water, sediments, and different freshwater fish species of River Kabul, Pakistan. The heavy metals were quantified in the samples with Atomic Absorption Spectrophotometer. Heavy metal contamination in fish muscles was characterized in terms of metal pollution index and biota-sediments accumulation factor, while human health risk was assessed through calculation of estimated weekly intake. The average concentrations of Cr, Ni, Cd, and Pb in muscle samples of the analyzed fish species at different sampling sites of the river ranged from 12.3 to 33.0, 33.2 to 109.2, 0.98 to 1.5, and 13.9 to 29.6 mg kg⁻¹ wet weight, respectively. Based on the current study data, consumption of the analyzed freshwater fish species from River Kabul was generally safe in terms of potential risk from Cd and Pb but the observed Ni accumulation may pose a potential health risk to regular/excessive fish consumers.
In the present study five heavy metals were analyzed in the milk samples of cow, buffalo and goat. The level of Pb was found to exceed the maximum permissible limit (0.02 μg/g) set by Codex Alimentarius Commission in 53% milk samples. In 44% milk samples the level of Cd was found to exceed the permissible limit (0.0026 μg/g) set by International Dairy Federation (1979). The mean levels of Ni, Cu and Co were found in the normal ranges. The data for estimated daily intake of heavy metals through milk showed that infants are most prone towards heavy metal toxicity due to the higher rate of milk consumption.
h i g h l i g h t s • Feeding behaviour was 27–63 times more sensitive than lethality in Daphnia magna. • Five out of seven mixtures interacted differently on lethal and sublethal endpoints. • Metals had the same order of toxicity for both endpoints (Cu > Cd > Ni > Zn). a b s t r a c t The toxicity of metal mixtures is currently of particular interest among aquatic toxicologists. To provide insight into whether the interaction of multiple metals is similar at different biological levels, the survival and feeding behavior of Daphnia magna were studied following exposure to four metals (Cd, Cu, Ni, Zn) and their binary and quaternary combinations. In terms of survival, Zn-Cu and Cu-Cd mixtures produced more-than-additive mortality, while Ni-Cd mixtures resulted in less-than-additive mortality. Regarding behavior, Zn-Cu and Zn-Cd mixtures produced a more-than-additive reduction in feeding rate. Four (i.e. Zn-Cu, Cu-Cd, Ni-Cd, and Zn-Cd) out of six binary mixtures in the present study interacted differently at the survival and behavioral levels, strengthening the emphasis on carefully selecting the toxicological endpoint when addressing metal mixture toxicity. The results of the present study demonstrated that metals are toxic to feeding behavior of D. magna at much lower concentrations (i.e. 27–63 times lower) compared to survival, suggesting that applying sub-lethal endpoints are required for producing protective regulations.
An assessment of the dietary risk of heavy metal exposure to humans is important since it is the main source of exposure. This study aimed to estimate the degree of contamination and assess the probable health risk in the prawn food chain. In prawn feed, the concentrations of metals were detected in the following order: Hg > Co > Pb > Cd. The concentrations of heavy metals in prawn were the highest for Co and lowest for Cd. Trace amounts of As and Cr were detected in the analyzed sample. Target hazard quotients for heavy metals for adults were >1 for Pb, Cd, Hg, and Co, and for children, the same were high for Co and Hg, indicating significant health risks upon dietary exposure. All the prawn samples contained nine-fold and fourteen-fold higher concentrations than the maximum acceptable levels for Pb and Hg, respectively (0.5 mg kg⁻¹; WHO/FAO). Human health risk due to the Co exposure is quite alarming as the level of exposure was found to be very high. In the prawn samples intended for human consumption, the hazard index (HI) was highest in the samples obtained from Bagerhat (3.25 in flesh and 3.26 in skin), followed by the samples obtained from Satkhira (2.84 in flesh and 3.10 in skin) and Dhaka City Corporation (2.81 in flesh and 3.42 in Skin); this indicates a potential risk of prawn consumption obtained from Southeast Bangladesh. This is particularly problematic as this area accounts for the majority of prawn production and export of the country.
Human society actually faces many environmental challenges such as environmental pollution, climate changes and loss of biodiversity. These issues induce major risks for ecosystems and are a serious threat for further life on Earth. Anthropogenic pressure may continue to exacerbate the present-day problems. Prevention and mitigation of environmental issues demands sound science and dedicated political support. For that, environmental chemistry is a central and multidisciplinary science that will provide new concepts and applied methods to solve actual environmental issues. Here, we outline the scope of environmental chemistry. The Anthropocene era and major chemical disasters are discussed. We present also the challenges of atmospheric chemistry, analytical chemistry, statistics and chemometrics, and education in environmental chemistry.
Anthropologic activities have transformed global biogeochemical cycling of heavy metals by emitting considerable quantities of these metals into the atmosphere from diverse sources. In spite of substantial and progressive developments in industrial processes and techniques to reduce environmental emissions, atmospheric contamination by toxic heavy metals and associated ecological and health risks are still newsworthy. Atmospheric heavy metals may be absorbed via foliar organs of plants after wet or dry deposition of atmospheric fallouts on plant canopy. Unlike root metal transfer, which has been largely studied, little is known about heavy metal uptake by plant leaves from the atmosphere. To the best of our understanding, significant research gaps exist regarding foliar heavy metal uptake. This is the first review regarding biogeochemical behaviour of heavy metals in atmosphere-plant system. The review summarizes the mechanisms involved in foliar heavy metal uptake, transfer, compartmentation, toxicity and in plant detoxification. We have described the biological and environmental factors that affect foliar uptake of heavy metals and compared the biogeochemical behaviour (uptake, translocation, compartmentation, toxicity and detoxification) of heavy metals for root and foliar uptake. The possible health risks associated with the consumption of heavy metal-laced food are also discussed.
In drinking water, arsenic (As) food chain accumulation may pose a risk to human health. An attempt was made to synthesise the published information concerning As trophic transfer along the food chain/web of various marine, freshwater, and terrestrial ecosystems. Some investigations included As speciation. Further objectives were to outline the factors potentially influencing As trophodynamics and to understand the consequence of As trophic transfer in the environment.
In this study, manganese (Mn) zinc (Zn), copper (Cu), cadmium (Cd) and lead (Pb) concentrations were determined in muscle and liver of Sind sardinella (Sardinella longiceps) collected from Balochistan coast, Pakistan, during autumn inter monsoon, north east monsoon, spring inter monsoon and south west monsoon during October 2005 - September 2006. Fish showed accumulation of Mn (1.73±0.96, 4.5±2.47 μg g-1), Zn (3.10±2.11, 23.82±9.77 μg g-1), Cu (3.18±1.50, 26.08±13.81 μg g-1), Cd (0.17±1.88, 0.91±0.61 μg g-1) and Pb (0.25±1.77, 1.33±0.53 μg g-1) in muscle, and liver respectively. Mn was above the permissible limits.
A characterization study of 7 hazardous (Hg, Pb, Cd, As, Cr, U, and Ni) and 11 essential (Co, Mo, Se, Cu, Zn, V, Ca, Al, Sr, Mn, and Fe) trace elements in date mussels (Lithophaga lithophaga,Linnaeus, 1758) was carried out by inductively coupled plasma mass spectrometer. Date mussels (231 individuals), caught in the Gulf of Manfredonia (Southern Italy), were divided into 4 size-related groups. The different tissues (muscle, stomach, hepatopancreas and rest of soft tissues) were separated and analyzed to study the capability of absorption of this species. No particular differences were reported on the basis of the shell size; the soft tissues play an important role on the accumulation levels of hazardous and essential trace elements. These marine animals may be considered a good bioindicator of marine environmental pollution for their longevity and habitat permanence peculiarities.
The muscle tissue of freshwater fish, Tor putitora netted from River Kabul was analysed to investigate the presence of heavy metal pollution in the river. For this purpose fish samples were collected from two sites - site 1 and 2 of highly polluted belt of the Main River. Both these samples were considered fish samples from polluted water (test sample) and were compared with the third fish sample (control sample) collected from the almost non polluted Warsak Dam (Site 3) upstream of the polluted part of the River. Metal bioaccumulation was analyzed in the muscle tissue. Muscle of fish from polluted river site 1 had accumulated 62.8% more chromium in polluted sample 1 and 60.3% more chromium in polluted sample 2, when compared with control, 46.9% more nickel in samples 1 and sample 2, 24.6% more lead in sample 1 and 172% in sample 2, 19.3% more copper in sample 1 and 31.8% more in sample 2, 56.5% more zinc in sample 1 and 44.1% more in sample 2 when compared with these parameters in control fish. In muscle zinc was found to be highly concentrated metal, whereas chromium was the least concentrated. The order of metal bioaccumulation in muscle was zinc > lead > nickel > copper > chromium.
A total of 484 rice samples were collected from five polluted areas in China to investigate the cadmium (Cd) contamination of rice and its potential health risks. The mean Cd contents of analyzed rice samples obtained from different areas ranged from 0.149 to 0.189 mg·kg(-1). Cd concentrations in more than 18 % of rice samples exceeded the maximum allowable Cd concentration, and the highest level of 41.1 % was observed in samples from Hezhang, Guizhou, which was characterized by serious Cd pollution. Target hazard quotient (THQ) values of 1.5 to 7.8 from rice intake indicated a significant non-carcinogenic health risk for humans, particularly for highly exposed consumers. Children are more at risk than adults, as indicated by the higher THQs. Moreover, carcinogenic risks of Cd from rice intake for average and high consumers in the selected areas were two to three and four to eight greater, respectively, than the threshold value recommended by the International Commission on Radiological Protection.
The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. These metals have been extensively studied and their effects on human health regularly reviewed by international bodies such as the WHO. Heavy metals have been used by humans for thousands of years. Although several adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues, and is even increasing in some parts of the world, in particular in less developed countries, though emissions have declined in most developed countries over the last 100 years. Cadmium compounds are currently mainly used in re-chargeable nickel-cadmium batteries. Cadmium emissions have increased dramatically during the 20th century, one reason being that cadmium-containing products are rarely re-cycled, but often dumped together with household waste. Cigarette smoking is a major source of cadmium exposure. In non-smokers, food is the most important source of cadmium exposure. Recent data indicate that adverse health effects of cadmium exposure may occur at lower exposure levels than previously anticipated, primarily in the form of kidney damage but possibly also bone effects and fractures. Many individuals in Europe already exceed these exposure levels and the margin is very narrow for large groups. Therefore, measures should be taken to reduce cadmium exposure in the general population in order to minimize the risk of adverse health effects. The general population is primarily exposed to mercury via food, fish being a major source of methyl mercury exposure, and dental amalgam. The general population does not face a significant health risk from methyl mercury, although certain groups with high fish consumption may attain blood levels associated with a low risk of neurological damage to adults. Since there is a risk to the fetus in particular, pregnant women should avoid a high intake of certain fish, such as shark, swordfish and tuna; fish (such as pike, walleye and bass) taken from polluted fresh waters should especially be avoided. There has been a debate on the safety of dental amalgams and claims have been made that mercury from amalgam may cause a variety of diseases. However, there are no studies so far that have been able to show any associations between amalgam fillings and ill health. The general population is exposed to lead from air and food in roughly equal proportions. During the last century, lead emissions to ambient air have caused considerable pollution, mainly due to lead emissions from petrol. Children are particularly susceptible to lead exposure due to high gastrointestinal uptake and the permeable blood-brain barrier. Blood levels in children should be reduced below the levels so far considered acceptable, recent data indicating that there may be neurotoxic effects of lead at lower levels of exposure than previously anticipated. Although lead in petrol has dramatically decreased over the last decades, thereby reducing environmental exposure, phasing out any remaining uses of lead additives in motor fuels should be encouraged. The use of lead-based paints should be abandoned, and lead should not be used in food containers. In particular, the public should be aware of glazed food containers, which may leach lead into food. Exposure to arsenic is mainly via intake of food and drinking water, food being the most important source in most populations. Long-term exposure to arsenic in drinking-water is mainly related to increased risks of skin cancer, but also some other cancers, as well as other skin lesions such as hyperkeratosis and pigmentation changes. Occupational exposure to arsenic, primarily by inhalation, is causally associated with lung cancer. Clear exposure-response relationships and high risks have been observed.