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Hexavalent chromium (Cr6+) is one of the stable oxidation states of chromium that has been reported to elicit various toxic effects in aquatic organisms. However, the mechanisms of Cr6+ toxicity are still poorly understood. Thus, the present study investigated the tissue accumulation, cytotoxic, oxidative stress, and immunotoxic effects of Cr6+ in juvenile Clarias gariepinus. The fish were exposed to waterborne Cr6+ concentrations (0, 0.42, 0.84, and 1.68 mg/L) for 28 days, after which they were sacrificed and various organs were harvested for the determination of Cr6+ levels. Other parameters that were indicators of oxidative stress, cytotoxicity, and immunotoxicity were measured. Cr6+ accumulated more in the kidney and liver of the exposed fish, especially at the highest concentration. The levels of lipid peroxidation and DNA fragmentation increased significantly in the exposed fish. The activities of superoxide dismutase and lactate dehydrogenase increased significantly in exposed fish compared to the control. The total white blood cells, lymphocytes, and neutrophils counts were significantly higher in the exposed fish compared to the control fish. The respiratory burst activity decreased significantly in the exposed fish while the myeloperoxidase content did not differ significantly. There were upregulations of TNF-α and HSP 70 while CYP II and MHC 2 were downregulated in the exposed fish. Also, exposure to Cr6+ resulted in various histopathological alterations in the architecture of the head kidney. The results indicate concentration-dependent toxic effects of Cr6+ in C. gariepinus. The study reveals the potentials of Cr6+ to accumulate in the different tissues of fish and caused cytotoxic, oxidative stress, and immunotoxic effects in the exposed fish. [ABSTRACT FROM AUTHOR]

In some areas, soil, sediment, water, and organic materials may exhibit elevated concentrations of various metals. Under certain conditions, these metals can take on most bioavailable forms. To assess the impacts and potential risks associated with elevated element concentrations, understanding the fraction of whole elements in water, sediment, and soil which are bioavailable is very important. The study aims to examine these conditions to accurately assess potential environmental impacts. For the study, searches were carried out using the keywords "bioavailability", "metal" and "environment" in various combinations in English. The search was limited to articles published open access in NCBI or PubMed, Scopus, and Google Scholar. The language of the manuscript was not restricted. The complex interactions of these diverse factors highlight the difficulty of assessing and understanding the bioavailability of metals in different environmental matrices. The study identified key factors affecting the bioavailability of the metal. These factors can change over time and among different microorganisms, plants, and animals. Research involving field and laboratory studies conducted at specific locations in soil, sediment, and flora using selective chemical extraction techniques is critical to a detailed understanding of the complex ecological processes associated with the bioavailability of metals to organisms.

Biotic samples from Algeciras Bay (South-west Europe) were studied to assess its ecological status, complementing the previous abiotic monitoring of trace metals in water and sediments. This bay is a densely populated area with intense port traffic and is highly industrialised with metal inputs. To study the impact of this, Zn, Cd, Pb, and Cu contents were determined in tissues of benthic (Solea senegalensis) and benthopelagic species (Scorpaena porcus, Trigloporus lastoviza, and Diplodus sargus sargus). Notable levels of Zn and Cu were found in the liver and gills of all fish species. Compared to international muscle guidelines, Pb sometimes exceeded the most restrictive values, outstanding S. porcus with 27% of samples above the permissible value. Metal pollution indexes revealed that the liver and gills of benthic species were more affected by metal pollution than benthopelagic species, especially in most industrialised sites. Particularly, S. senegalensis presented a higher accumulation factor from sediment of Cd and Cu in the liver (30.1 and 345.1), probably due to the close interaction as benthic species. Among the species studied, S. senegalensis and D. sargus sargus proved to be the best representative and useful bioindicators of metal-polluted environments as this bay. The results were consistent with the findings from the abiotic samples. [ABSTRACT FROM AUTHOR]

The ecological status of Algeciras Bay (South-west Europe), highly influenced by anthropogenic activities, was assessed by monitoring Zn, Cd, Pb, and Cu in water and sediment samples. Total contents and metal fractions with different availabilities and their spatial-seasonal distribution were determined. The trend in water and sediment contents were Zn > Pb ≈ Cu > Cd, without significant seasonal variations. Sites 3 and 4, closest to industrial activities, had the highest metal concentrations, mainly in sediments. Cd showed low partition coefficient in water, indicating higher bioavailability. Total metal content in sediments exceeded the threshold effect level for Cu and were close to Pb. The BCR procedure revealed the highest availabilities for Cd and Pb, due to its higher content in exchangeable and reducible fractions. Higher Pb levels (21.4 ± 5.1 mg/kg) were found in sediments of this bay compared with other ecosystems. Pollution indexes for sediment quality revealed that site 3 was the most polluted (CF = 7.12 and Igeo = 2.25). For an integrative study of the ecological status of this significant bay, these results have been complemented with the metal evaluation in benthic and benthopelagic fish tissues in Ecological status of Algeciras Bay, in a highly anthropised area in south-west Europe, through metal assessment—Part II: Biotic samples. [ABSTRACT FROM AUTHOR]

This study attempts to assess the spatio-temporal distribution of total organic carbon (TOC) and heavy metals in one of the Ramsar wetlands of Indo-Burmese province. Water samples were collected from 10 sampling points during the premonsoon, monsoon and postmonsoon season of 2016 and 2017. The general water parameters such as low DO, high BOD, and high fluoride imply the wetland water's deteriorated quality. The mean TOC of water was estimated to be 2.4 ± 0.33 ppm, the first report from Deepor Beel. Pearson's correlation coefficient showed a significant positive relation (> 0.7) between TOC, phosphate, and nitrate, which indicates the seasonal inflow of these parameters from a similar source. The computed heavy metal indices revealed that most of the water samples were highly contaminated by metals. The metal concentration recorded in the selected macrophytes and fishes species was far above the concentration of the respective metal in the water samples. Metal distribution in plant samples disclosed that Euryale ferox showed better accumulation ability than Hydrilla verticillata and Eichhornia crassipes. Among the fish species, the highest metal accumulation was recorded in Xenentodon cancila (zinc, iron, manganese, and nickel) and Channa punctatus (lead and cadmium). In the fish samples, metal accumulation was found to be higher in the organs (particularly in the kidney) than in the muscles. Bioconcentration factor revealed a high metal accumulation in the submerged type plants and surface feeder fishes. [ABSTRACT FROM AUTHOR]

Elevated heavy metal concentrations in soils are a cause for concern as they are hazardous to soil organisms including earthworms which are considered as ecosystem engineers. Current ecotoxicity tests predominantly use temperate earthworm species, and thus there is the need to include a broader genera of native species to improve ecological risk assessment. Alma nilotica, is a tropical anecic earthworm species that survives well under laboratory conditions and has potential for use in ecotoxicology testing but lacks published toxicity data for important pollutants. Growth and reproduction bioassays were carried out with A. nilotica to determine the relationship between the concentrations of Cu, Zn, Pb and Cr in spiked soils and their bioaccumulation and toxic effects. Positive linear relationships were found between soil-metal and internal earthworm-metal concentrations. Cu did not inhibit growth up to 35 days of exposure but became toxic with longer exposure duration. Zn was not regulated by A. nilotica although it is an essential metal that is well regulated by Eisenia sp. commonly used in standard ecotoxicity tests, showing differences in metal regulation by earthworms of different ecological categories. Based on bioaccumulation factors (BAFs), growth inhibition and reproduction effects the metals were ranked in decreasing toxicity as Pb > Cr > Zn > Cu. The mean 20% Internal Effects Concentrations (IEC20s) for reproduction were 1.04, 2.9, 8.3 and 224.2 mg metal kg−1 earthworm for Pb, Cr, Zn and Cu respectively. These data can contribute to the improvement of metal risk assessment particularly in tropical contexts. [ABSTRACT FROM AUTHOR]

Mine wastewater often contains dissolved metals at concentrations too low to be economically extracted by existing technologies, yet too high for environmental discharge. The most common treatment is chemical precipitation of the dissolved metals using limestone and subsequent disposal of the sludge in tailing impoundments. While it is a cost‐effective solution to meet regulatory standards, it represents a lost opportunity. In this study, we engineered Escherichia coli to overexpress its native NikABCDE transporter and a heterologous metallothionein to capture nickel at concentrations in local effluent streams. We found the engineered strain had a 7‐fold improvement in the bioaccumulation performance for nickel compared to controls, but also observed a drastic decrease in cell viability due to metabolic burden or inducer (IPTG) toxicity. Growth kinetic analysis revealed the IPTG concentrations used based on past studies lead to growth inhibition, thus delineating future avenues for optimization of the engineered strain and its growth conditions to perform in more complex environments. [ABSTRACT FROM AUTHOR]

Human industry and land use has led to the anthropogenic release of manganese (Mn) into the air and soil near manufacturing centers. Overexposure to Mn can cause considerable health problems in birds. We studied whether the concentration of Mn in bird feathers correlates with the distance to point sources of Mn air emissions. Feathers were collected from Tufted Titmice (Baeolophus bicolor) at two sites in western Pennsylvania, USA. One site was in proximity (0.3 km) to a steel plant with documented Mn releases, and the other site was in a different town about 4.0 km away from other steel plants with documented Mn releases. Using the microwave plasma–atomic emission spectrometer (MP–AES), we found that tail feathers collected from nearest to a steel plant had a significantly higher concentration of Mn compared to the samples from the site further from the emission source. A body mass index was calculated for each set of birds; however, the indices did not vary significantly. This is the first published study of Mn sequestration in Tufted Titmouse feathers. This study develops our general understanding of the potential use of bird feathers as non-invasive bioindicators of environmental metal exposure.

Biotic samples from Algeciras Bay (South-west Europe) were studied to assess its ecological status, complementing the previous abiotic monitoring of trace metals in water and sediments. This bay is a densely populated area with intense port traffic and is highly industrialised with metal inputs. To study the impact of this, Zn, Cd, Pb, and Cu contents were determined in tissues of benthic (Solea senegalensis) and benthopelagic species (Scorpaena porcus, Trigloporus lastoviza, and Diplodus sargus sargus). Notable levels of Zn and Cu were found in the liver and gills of all fish species. Compared to international muscle guidelines, Pb sometimes exceeded the most restrictive values, outstanding S. porcus with 27% of samples above the permissible value. Metal pollution indexes revealed that the liver and gills of benthic species were more affected by metal pollution than benthopelagic species, especially in most industrialised sites. Particularly, S. senegalensis presented a higher accumulation factor from sediment of Cd and Cu in the liver (30.1 and 345.1), probably due to the close interaction as benthic species. Among the species studied, S. senegalensis and D. sargus sargus proved to be the best representative and useful bioindicators of metal-polluted environments as this bay. The results were consistent with the findings from the abiotic samples.

The ecological status of Algeciras Bay (South-west Europe), highly influenced by anthropogenic activities, was assessed by monitoring Zn, Cd, Pb, and Cu in water and sediment samples. Total contents and metal fractions with different availabilities and their spatial-seasonal distribution were determined. The trend in water and sediment contents were Zn > Pb ≈ Cu > Cd, without significant seasonal variations. Sites 3 and 4, closest to industrial activities, had the highest metal concentrations, mainly in sediments. Cd showed low partition coefficient in water, indicating higher bioavailability. Total metal content in sediments exceeded the threshold effect level for Cu and were close to Pb. The BCR procedure revealed the highest availabilities for Cd and Pb, due to its higher content in exchangeable and reducible fractions. Higher Pb levels (21.4 ± 5.1 mg/kg) were found in sediments of this bay compared with other ecosystems. Pollution indexes for sediment quality revealed that site 3 was the most polluted (CF = 7.12 and Igeo = 2.25). For an integrative study of the ecological status of this significant bay, these results have been complemented with the metal evaluation in benthic and benthopelagic fish tissues in Ecological status of Algeciras Bay, in a highly anthropised area in south-west Europe, through metal assessment—Part II: Biotic samples.

Abstract Mine wastewater often contains dissolved metals at concentrations too low to be economically extracted by existing technologies, yet too high for environmental discharge. The most common treatment is chemical precipitation of the dissolved metals using limestone and subsequent disposal of the sludge in tailing impoundments. While it is a cost‐effective solution to meet regulatory standards, it represents a lost opportunity. In this study, we engineered Escherichia coli to overexpress its native NikABCDE transporter and a heterologous metallothionein to capture nickel at concentrations in local effluent streams. We found the engineered strain had a 7‐fold improvement in the bioaccumulation performance for nickel compared to controls, but also observed a drastic decrease in cell viability due to metabolic burden or inducer (IPTG) toxicity. Growth kinetic analysis revealed the IPTG concentrations used based on past studies lead to growth inhibition, thus delineating future avenues for optimization of the engineered strain and its growth conditions to perform in more complex environments.

Simple Summary: Steel production emits manganese and other heavy metals into the environment, where these byproducts can lead to health problems in humans and other animals. Birds have historically been used to detect harmful chemicals in the air, and in this paper, we show that this role continues into the present day. Feathers of a small terrestrial songbird, the Tufted Titmouse, were collected from live birds captured both near (0.3 km) and far (4.0 km) from steel production facilities in western Pennsylvania, USA. Tail feathers from birds living near the facilities had significantly higher amounts of manganese embedded in their structure compared to the feathers of birds living farther away. This shows that manganese is present in the environment, is localized at industrial sites, is encountered by birds, and is sequestered in their tissues. Animals could suffer ill health if exposures are high enough. Feather data cannot be used to assess the magnitude of this health risk since metals laid down within feathers are no longer circulating in the birds' bodies. However, our data do suggest that the environmental monitoring of manganese should continue, as inadvertent exposure is still occurring. Human industry and land use has led to the anthropogenic release of manganese (Mn) into the air and soil near manufacturing centers. Overexposure to Mn can cause considerable health problems in birds. We studied whether the concentration of Mn in bird feathers correlates with the distance to point sources of Mn air emissions. Feathers were collected from Tufted Titmice (Baeolophus bicolor) at two sites in western Pennsylvania, USA. One site was in proximity (0.3 km) to a steel plant with documented Mn releases, and the other site was in a different town about 4.0 km away from other steel plants with documented Mn releases. Using the microwave plasma–atomic emission spectrometer (MP–AES), we found that tail feathers collected from nearest to a steel plant had a significantly higher concentration of Mn compared to the samples from the site further from the emission source. A body mass index was calculated for each set of birds; however, the indices did not vary significantly. This is the first published study of Mn sequestration in Tufted Titmouse feathers. This study develops our general understanding of the potential use of bird feathers as non-invasive bioindicators of environmental metal exposure. [ABSTRACT FROM AUTHOR]

Concentrations of essential metals (Cu, Co, Cr, Fe, Ni, Mn, and Zn) and non-essential and toxic metals (Ag, Cd, Hg, and Pb) were quantified in hepatopancreas and abdominal muscle for 73 specimens (37 males and 36 females) of Procambarus clarkii from Lake Trasimeno (Italy) in a year's campaign (July 2018 to June 2019). Elemental concentrations determined in crayfish differed in tissues, seasons, and gender. Both sexes showed lower concentrations in abdominal muscle than in hepatopancreas. Essential metals accumulated in higher concentrations in both tissues than non-essential elements, while associations between essential metals were stronger, especially for females; however, a strong correlation was also observed between Cu and Ag in both sexes. No significant differences in concentrations were recorded between sexes for all seasons; contrarily, significant differences among the total seasonal concentrations (males plus females) were observed only for essential metals and for Ag. Seasonal Toxic Contamination Index (TCI) for Cr, Ni, Cu, Zn, Cd, Pb, and Hg were calculated to assess the toxicity level of metals in the sediments. TCI higher than 1 was detected for Ni only in summer, confirming the close connection between the fluctuating hydrological levels of the shallow Lake Trasimeno, strongly dependent on precipitation, and the metal contamination levels of sediments. [ABSTRACT FROM AUTHOR]

This study aims to verify the relevance of Brachidontes pharaonis to assess the ecotoxicological status of polluted sites. For this, the levels of some heavy metals (i.e. Zn, Cu, Pb, and Cd) and a battery of biomarkers including metallothionein (MT), malondialdehyde (MDA), reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) were assessed in mussels collected from the harbor of Rades (North), and the harbor of Zarzis (South). Moreover, abiotic parameters including temperature, salinity, pH, and dissolved oxygen were assessed. Results from the ICP-OES showed that the southern population exhibited a higher metal pollution index with significantly higher Zn, Cu, and Pb concentrations. Moreover, the specimens from Zarzis displayed significantly higher levels of MDA, MT, GSH, GPx, SOD, and CAT reflecting higher levels of oxidative and chemical stress. These results emphasize the potential utility of B. pharaonis for the monitoring of heavily impacted sites. [ABSTRACT FROM AUTHOR]

To assess its utility as a bioindicator of estuarine contamination, Amphibola crenata , a pulmonate mud snail, was collected from 17 estuaries in New Zealand. Whole-body soft tissue trace element concentrations were measured via quadrupole inductively coupled plasma mass spectrophotometer (Q-ICP-MS) and were found to be significantly positively correlated with sediment trace element profiles for arsenic, copper and lead. Snails from polluted estuaries generally displayed higher ammonia excretion rates, elevated whole-body soft tissue catalase activity and lipid peroxidation compared to snails from reference sites. Across all sites haemolymph glucose was positively correlated with the tissue burdens of arsenic, copper, nickel and zinc, while haemolymph protein was negatively correlated with arsenic, cadmium and zinc soft tissue concentrations, indicative of altered energy metabolism associated with trace element contamination. Overall, sites were distinguishable by application of the array of measures employed. Our findings suggest that gastropods have significant value as bioindicators of estuarine health. • Metal burdens and biomarkers were investigated in Amphibola crenata. • Tissue As, Cu and Pb burdens were significantly related to their sediment levels. • Ammonia excretion and catalase activity were predictive of site contamination. • This estuarine gastropod has significant potential as an estuarine bioindicator. [ABSTRACT FROM AUTHOR]

The present study has been elaborated with the aim of justifying the high efficiency of in-situ slaughterhouse sludge recycling and its usage in Lolium perenne cultures. Stabilized slaughterhouse sludge was used to complete the high deficiency in nutrients of the poor terrains. Slaughterhouse sludge represents an excessive, final by product from a meat-processing unit in Western Romania. It contains 59.78-90.77% easily bio-degradable organic substances. Moreover, it has compounds containing nitrogen and phosphorus, total N=1.922-3.318%, total P=1107-1126mg*kg‘ 'D.M. The experimental variants have been prepared, having the following characteristics: control variants of non fertilized soils and variants of soils fertilized with slaughterhouse sludge, 50t*ha''. The experimental variants used were arranged in a completely randomized block design, with three replicates each. The efficiency of fertilization with slaughterhouse sludge was a 30-35% rise in the quantity of grass harvested vs. the quantities harvested from the control variants. The quantity of Cd and Pb has been determined from the aerial parts of the harvested plants and they were below the maximum limit admitted by the sanitary regulations in Romania. Cr didn’t bio-accumulate in plants at a detection limit. The quantity of other metals determined from the aerial parts of the plants was low: i.e.

The capacity to accumulate metal in the lichen communities has been used to identify the level of air pollution due road traffic. Several analyses have been conducted in the study, on tissue from lichens collected from six areas: the park of a town, various sites on the town’s freeway and on a county road segment with moderate traffic. The analyzed lichens were from the Parmelia spp. species which grow naturally on trees found in borderline lanes of motorways. Based on the degree of heavy metal accumulation such as Cd, Cr, Cu, Fe Mn, Pb, Ni and Zn in the Parmelia spp. lichens, a correlation has been made, with the road traffic. According to the metal bioaccumulation degree in lichens tissue, it has been established that the sources such as traffic from the outskirts of cities, from the perimeter of gas stations and of county roads continuously spread products which contain these elements, into the atmosphere. The fast information regarding the quality of the air in the environment allows the use of lichens as organism which can indicate environmental conditions and their modification by accumulating substances.

The study compares the amounts of Zea mays, grains, cobs and stalks, harvested on fertilized / unfertilized variant with different fertilizers: M-control, V1-fertilized with sewage sludge 50 t/ha + indigenous volcanic tuff, 5 t/ha, V2-fertilized with sewage sludge 50 t/ha, V3-fertilized with cattle manure, 50 t/ha. The amount of grains and cobs harvested from variant fertilized with cattle manure or sewage sludge mixed with indigenous volcanic tuff were similar. The amount of cobs and grains harvests from variant fertilized with sewage sludge mixed with indigenous volcanic tuff were higher between 15.1-17.5%, respectively 15.4-19.1% than those harvested from variant fertilized with sewage sludge. The indigenous volcanic tuff used as addition at sewage sludge was an important factor for the reduction of bioavailability of metals in the aerial tissues of the plant. The amount of toxic metals, Cd, Cr, Ni, Pb and Zn from the tissues of Zea mays plants was below the maximum limits allowed by the UE rules.

This study determined the concentration of trace metals in vegetables (lettuce, tomato and cabbage) from Gombe markets, Gombe State, Nigeria. A total of 60 samples of vegetables were analyzed for trace metals (Cd, Pb, Mn, Cr, Zn, Ni and Cu) using Atomic Absorption Spectrophotometer (AAS). The mean concentration of Cd in lettuce, tomato and cabbage samples ranged from (0.05 - 0.06 mg/kg), (0.03 - 0.07 mg/kg) and (0.08 - 0.90 mg/kg), Pb ranged from (BDL - 0.02 mg/kg), (BDL - 0.03 mg/kg) and (0.01 - 0.02 mg/kg), Mn ranged from (0.27 - 1.02 mg/kg), (0.09 - 0.12 mg/kg) and (0.25 - 0.31 mg/kg), Cr ranged from (0.05 - 0.65 mg/kg), (0.04 - 0.05 mg/kg) and (0.03 - 0.05 mg/kg), Zn ranged from (2.67 - 3.32 mg/kg), (1.93 - 2.87 mg/kg) and (2.45 - 3.26 mg/kg), Ni ranged from (0.68 - 0.77 mg/kg), (0.23 - 0.26 mg/kg) and (0.73 - 0.86 mg/kg), and Cu ranged from (0.95 - 0.97 mg/kg), (0.76 - 0.83 mg/kg) and (0.94 - 1.00 mg/kg) respectively. The abundance of trace metals was found in decreasing order: Zn > Cu > Ni > Mn > Cr > Cd > Pb in lettuce, tomato and cabbage samples. The concentration of trace metals in the different vegetables were below the World Health Organization/Food and Agriculture Organization (WHO/ FAO) standard, except Cd in all studied samples. Therefore, monitoring and strict regulation is recommended to control the safety of vegetables sold in these markets. [ABSTRACT FROM AUTHOR]

Histopathologies are widely recognized as biomarkers of environmental pollution. In this sense, we evaluated the putative relationship of gill histopathologies and distinct ecological impacts in two regions of Todos os Santos Bay (BTS), Brazil, the largest bay in Northeastern Brazil, South Atlantic. We compared the presence and concentration of metals (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn) in water, sediments, and gills and gill histopathologies of a demersal fish (Diapterus rhombeus) and a benthic fish (Ogcocephalus vespertilio). As expected, fish and sediment samples from historically contaminated areas (Aratu) showed more remarkable traces of metals than apparently low-impact areas (Jaguaripe). Likewise, the DTC (degree of tissue change) index and the volume densities were higher in fish caught in Aratu. In addition, the Diapterus rhombeus species showed more potential than Ogcocephalus vespertilio for risk assessment as it showed more responses to the environment reflected on more histopathologies. These data support the effectiveness of incorporating functional gill morphology to monitor impacts on estuarine biota that can be used as a reference to improve the management of ecosystems and prevent harm to human health. [ABSTRACT FROM AUTHOR]

This study determined the concentration of trace metals in vegetables (lettuce, tomato and cabbage) from Gombe markets, Gombe State, Nigeria. A total of 60 samples of vegetables were analyzed for trace metals (Cd, Pb, Mn, Cr, Zn, Ni and Cu) using Atomic Absorption Spectrophotometer (AAS). The mean concentration of Cd in lettuce, tomato and cabbage samples ranged from (0.05 - 0.06 mg/kg), (0.03 - 0.07 mg/kg) and (0.08 - 0.90 mg/kg), Pb ranged from (BDL - 0.02 mg/kg), (BDL - 0.03 mg/kg) and (0.01 - 0.02 mg/kg), Mn ranged from (0.27 - 1.02 mg/kg), (0.09 - 0.12 mg/kg) and (0.25 - 0.31 mg/kg), Cr ranged from (0.05 - 0.65 mg/kg), (0.04 - 0.05 mg/kg) and (0.03 - 0.05 mg/kg), Zn ranged from (2.67 - 3.32 mg/kg), (1.93 - 2.87 mg/kg) and (2.45 - 3.26 mg/kg), Ni ranged from (0.68 - 0.77 mg/kg), (0.23 - 0.26 mg/kg) and (0.73 - 0.86 mg/kg), and Cu ranged from (0.95 - 0.97 mg/kg), (0.76 - 0.83 mg/kg) and (0.94 - 1.00 mg/kg) respectively. The abundance of trace metals was found in decreasing order: Zn > Cu > Ni > Mn > Cr > Cd > Pb in lettuce, tomato and cabbage samples. The concentration of trace metals in the different vegetables were below the World Health Organization/Food and Agriculture Organization (WHO/ FAO) standard, except Cd in all studied samples. Therefore, monitoring and strict regulation is recommended to control the safety of vegetables sold in these markets.

The term "Plastisphere" refers to the biofilm layer naturally formed by microorganisms attaching to plastic surfaces. This layer possesses the capability to adsorb persistent organic and inorganic pollutants, particularly trace metals, which are the focus of this research study. Immersion experiments were concurrently conducted in five locations spanning four European countries (France, Ireland, Spain, and Italy) utilising eight distinct polymers. These immersions, repeated every three months over a one-year period, aimed to evaluate the baseline bioaccumulation of 12 trace metals. The study underscores the intricate nature of metal bioaccumulation, influenced by both micro-scale factors (such as polymer composition) and macro-scale factors (including geographical site and seasonal variations). Villefranche Bay in France exhibited the lowest metals bioaccumulation, whereas Naples in Italy emerged as the site where bioaccumulation was often the highest for the considered metals. Environmental risk assessment was also conducted in the study. The lightweight nature of certain plastics allows them to be transported across significant distances in the ocean. Consequently, evaluating trace metal concentrations in the plastisphere is imperative for assessing potential environmental repercussions that plastics, along with their associated biota, may exert even in locations distant from their point of emission. [Display omitted] • Anthropogenic activities have a direct impact on the metal accumulation in the plastisphere. • The biopolymer PLA and fossil-fuel based polymers behave similarly. • The plastisphere diversity, and not its biomass, influence metal bioaccumulation. • Bioaccumulation of metals in the plastisphere is a potential trophic risk. [ABSTRACT FROM AUTHOR]

The biggest world tailing dam rupture occurred in Brazil in 2015, releasing approximately 32 million m3 of iron tailings in the Doce River watershed, along its 660 km trajectory, reaching the Atlantic Ocean. This disaster significantly altered water and soil properties, increasing the soil metal contents, mainly iron concentration. Little is known about the concentration of toxic elements in plants grown in these areas. Brachiaria decumbens stands out as the most cultivated grass in the affected areas and is widely used for cattle grazing. This study verified the metal contents in soils and in samples of B. decumbens grown in the initial pathway of the debris flow. It was noted that the tailing deposition altered the substrate chemically, increasing Fe by 181% and reducing Zn soil contents by 188%. However, the metal contents in the forage grass were below the toxic limit for cattle feed. In addition, the results suggest that the natural geological characteristics of the region also influenced the metal contents in plants since those plants grown in nonaffected areas also showed high metal concentrations. The impacted area soils had a slightly basic pH, which can reduce the metal availability. Considering that, in the future, these soils would return to their natural acid state, the metal contents in plants grown in the affected regions could probably increase. Thus, long‐term studies are needed to ensure the food safety of the forage production in these areas. Integr Environ Assess Manag 2022;18:528–538. © 2021 SETAC KEY POINTS: The tailing deposition chemically altered the substrate, increasing Fe and reducing Zn contents. The metal contents in the forage grass were below the toxic limit for cattle feed. Long‐term studies are needed to ensure the food safety of the forage production in these areas. Brachiaria decumbens has developed mechanisms and adaptive strategies to cope with high soil metal contents, so it can limit absorption and/or accumulation of toxic elements. [ABSTRACT FROM AUTHOR]

This study aimed at determining in animal model the health effects of in situ exposure to landfill chemicals. We evaluated metal concentrations in tissues and cytogenetic and clinico-biochemical effects in Wistar rats (Rattus norvegicus) exposed in situ at Olusosun landfill in Lagos, Nigeria. Male rats (n = 30/point) were exposed at three different points to ambient air and underground water (via drinking) at the landfill for 4-, 8-, 12-, 16-, 20- and 24-week periods. Rats concurrently sited at a residential area, 17.3 km from the landfill site served as control. There was significantly (p < 0.05) time-dependent: accumulation of lead, cadmium, chromium, copper and zinc in the liver and kidney and increase in body weight gain, in exposed rats compared to control. There was significant induction of micronuclei and cytotoxicity (reduced PCE/NCE ratios) in exposed rats. Haematological parameters (RBC, PCV, Hb and WBC) and serum biomarkers of hepato-renal damage [aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH) activities; creatinine and urea levels] revealed significant increases. There was significant increase in hepatic levels of reduced glutathione, malondialdehyde, catalase activities, and decrease in superoxide dismutase, at all periods. Chromium and copper concentrations in the liver and kidney revealed significant positive correlations with either one or more of AST, ALT, LDH and urea. Significant metal concentrations in the underground water and tissues suggest that heavy metals are responsible for the observed alterations, and this may have been via oxidative stress. These findings suggest potential health risk due to occupational and residential exposure to landfill pollutants. [ABSTRACT FROM AUTHOR]

The presence of metal contaminants in agricultural soils and subsequent uptake by food crops can pose serious human health risk. In this study, we assessed the levels of toxic metals – arsenic, chromium, copper, iron, manganese, nickel, and zinc – in soils and some edible root tuber crops from two gold mining and two non-mining communities in Ghana to evaluate the potential human health risks associated with exposure to these metals. Concentrations of the metals in 154 soil and edible root tuber samples were analyzed using field portable x-ray fluorescence spectrometer prior to confirmation by inductively coupled plasma mass spectrometry. Bioaccessibility of the metals was determined using an in vitro physiologically based extraction technique. Concentrations of the metals were generally higher in the gold mining communities than in the non-mining communities. The contamination indices indicated low to moderate contamination of the soil and food crops. Bioaccessibility for the metals varied from 1.7% (Fe) to 62.3 (Mn). Overall, the risks posed by the metals upon consumption of the tubers were low. [ABSTRACT FROM AUTHOR]

Coastal eutrophication is an indisputable reality and becoming a worldwide concern. However, whether and how eutrophication affects metal bioaccumulation in marine bivalves have not yet been elucidated. Here, we present the potential influence of coastal eutrophication on metal bioaccumulation in the Manila clam Ruditapes philippinarum. The degree of coastal eutrophication was examined monthly over a 1-year period at three sampling sites. The bioconcentration factor (BCF), biosediment accumulation factor (BSAF) and metal pollution index (MPI) were applied to evaluate the efficiency of metal bioaccumulation in R. philippinarum. BCF and BSAF indicated that eutrophication did not significantly affect the bioaccumulation of Cr, Cu, Zn, Cd, Pb, Hg, and As in R. philippinarum. However, up to 56% of MPI variation can be related to the level of eutrophication. Therefore, further research should address the synergistic effects of eutrophication and metal pollution on coastal ecosystems.

Metallothioneins (MTs) are low molecular weight cysteine-rich proteins that bind to metals. Owing to their high cysteine (Cys) content, MTs are effective mediators of heavy metal detoxification. To enhance the heavy metal binding ability of MT from the freshwater crab Sinopotamon henanense (ShMT), sequence-based multiple sequence alignment (MSA) and structure-based molecular docking simulation (MDS) were conducted in order to identify amino acid residues that could be mutated to bolster such metal-binding activity. Site-directed mutagenesis was then used to modify the primary structure of ShMT, and the recombinant proteins were further enhanced using the SUMO fusion expression system to yield SUMO-ShMT1, SUMO-ShMT2, and SUMO-ShMT3 harboring one-, two-, and three- point mutations, respectively. The resultant modified proteins were primarily expressed in a soluble form and exhibited the ability to readily bind to heavy metals. Importantly, these modified proteins exhibited significantly enhanced heavy metal binding capacities, and they improved Cd2+, Cu2+ and Zn2+ tolerance and bioaccumulation in Escherichia coli (E. coli) in a manner dependent upon the number of introduced point mutations (SUMO-ShMT3 > SUMO-ShMT2 > SUMO-ShMT1 > SUMO-ShMT > control). Indeed, E. coli cells harboring the pET28a-SUMO-ShMT3 expression vector exhibited maximal Cd2+, Cu2+, and Zn2+ bioaccumulation that was increased by 1.86 ± 0.02-, 1.71 ± 0.03-, and 2.13 ± 0.02-fold relative to that in E. coli harboring the pET28a-SUMO-ShMT vector. The present study offers a basis for the preparation of genetically engineered bacteria that are better able to bioaccumulate and tolerate heavy metals, thus providing a foundation for biological heavy metal water pollution treatment.

Copper pyrithione (CuPT) is used as a co-biocide in new antifouling paints but its toxicity remains little known. To compare the toxicity of copper-based compounds, rainbow trout (Oncorhynchus mykiss) larvae were exposed for 8-day to CuPT and CuSO 4 at equivalent copper concentrations. CuPT exposure led to the greatest accumulation of Cu in larvae. Exposure to 10 µg.L−1 CuPT induced 99% larval mortality but only 4% for CuSO 4 -exposed larvae. The larval development and growth were affected by CuPT (from 0.5 µg.L−1 Cu) but not by CuSO 4. Lipid peroxidation was not induced by either contaminant. The expression of genes involved in oxidative stress defence, detoxification and copper transport was induced in larvae exposed to CuSO 4 and CuPT but at higher concentrations for CuPT. This study highlights the marked toxicity of CuPT for early life stages of fish and raises the question of the possible environmental risks of this antifouling compound. [Display omitted] • Rainbow trout larvae were exposed for 8 day to CuPT or CuSO 4. • CuPT but not CuSO 4 increased Cu tissue content. • CuPT but not CuSO 4 induced 99% of larval mortality at 10 µg Cu2+. L−1. • CuPT at dose of 0.5 µg Cu2+. L−1 impacted the growth of larvae. • Both compounds induced an overexpression of genes involved in metal transport, antioxidant defence and detoxification. [ABSTRACT FROM AUTHOR]

Spatial variability of Cd, Cu, Cr, Ni, Zn, Fe, Mn, Pb and metallothionein (MT) concentrations were determined in mesozooplankton samples along the west-east axis of the Cretan Passage in the western Levantine Sea (Eastern Mediterranean). Metal and MT values from the present study are proposed as background levels, due to the lack of substantial anthropogenic activities in the area, where only maritime traffic and atmospheric deposition could be potential sources. Higher concentrations, of both metals and MTs, were recorded mainly at the western stations indicating higher metal bioavailability than in the eastern part. An inverse relationship of the metal zooplankton levels with zooplankton biomass, abundance and vital rates (production, respiration and ingestion rates), as well as salinity, was evident. We discuss the hypothesis that physical and biological characteristics of the marine environment, affecting growth dynamics of phytoplankton and zooplankton communities, may also act on metal uptake in oligotrophic marine systems. • Zooplankton metal levels were inversely correlated to physiological parameters. • Higher salinity at the eastern stations suppressed zooplankton metal levels. • Predominance of gelatinous organisms over copepods resulted in lower metal levels. • Metal and MT concentrations considered as background levels for the area. [ABSTRACT FROM AUTHOR]

Concentrations of aluminium, cadmium, chromium, lead, nickel and zinc in muscle and liver of a marine fish in Indo-Pacific region, Siganus javus captured in Negombo estuary were evaluated and potential human health risks associated with dietary exposure were assessed. Of the six metals analyzed, zinc was the most abundant metal in both tissues. No significant differences were found between muscle and liver with respect to cadmium and lead concentrations whereas concentrations of other metals were higher in liver compared to muscle. In human health perspective, estimated target hazard quotients for cadmium and lead were greater than the threshold of one indicating potential non-cancer health risks to heavy consumers. Estimated excess cancer risk of cadmium indicate carcinogenic health risks associated with their consumption even at moderate meal frequencies. The results revealed that consumption of S. javus from the estuary needs to be limited concerning non-cancer and cancer risks to human health. • Of the six metals analyzed, zinc was the most abundant metal in muscle and liver. • Except cadmium and lead, metals in muscle were below the maximum allowable levels. • THQ estimates for cadmium and lead indicated non-carcinogenic health risks to human. • Excess cancer risk estimates indicate cancer risks associated with cadmium exposure. • Fish consumption limits were estimated for safeguarding health of fish consumers. [ABSTRACT FROM AUTHOR]

The electric charge at a reactive interface influences the diffusion rate of ionic species towards the interface as well as their local concentration profiles. For metal ions (M) and their complexes (ML) formed with ligands (L), the interfacial electric field at a metal-consuming interface will lead to coupling between reaction layer and electric Debye layer, interfacial polarization of species concentrations and, thereby, so-far unexplored changes in ML contribution (lability) to sustain or not metal accumulation fluxes. A formalism and computational approach -based on coupled steady-state Nernst-Planck equations corrected for interfacial electrostatics and chemical kinetics- are here elaborated to obtain relevant metal surface flux and spatial distributions of M, L and ML. ML lability is subsequently derived and evaluated for practical settings of ML chemodynamics and macrosurface electrostatics under metal sink boundary condition. The extent to which the interfacial electric field affects lability of metal complexes depends on the charges of the reactive species and macrosurface. For example, repulsive M/ML-macrosurface interactions lead to significant loss of lability. Mass transfer features of ligands, even when present in large excess in bulk solution, are also found to impact on lability, even for moderately charged reactive surfaces. Predictions are in qualitative agreement with the available experimental data. [Display omitted] [ABSTRACT FROM AUTHOR]

This study provides the first geographic and temporal large-scale analysis of Cu stable isotope compositions in indigenous oysters to biomonitor anthropogenic Cu inputs in aquatic systems. It includes oyster samples from French marine environments with distinct Cu-pollution levels and histories and extends over several decades of biomonitoring. Sample series composed of oysters from the same season and similar size/age intended to avoid biological biases. Oysters in macrotidal estuaries (Loire and Gironde, Western France) display fluctuating Cu concentrations without clear temporal trends, challenging to infer anthropogenic influence. Conversely, the time series of their Cu isotope ratios indicate a constant proportion of natural and anthropogenic Cu sources since the 1980s. In contrast, Cu isotope compositions in oysters from the progressively developing locales (urbanization and recreational boating) of Arcachon and Vilaine bays shift positively over time, along with increasing Cu concentrations. This finding suggests a gradual augmentation in the bioaccumulation of anthropogenic Cu over time. Thus, Cu isotope compositions in oysters is an unambiguous and robust approach to pinpoint anthropogenic Cu contamination in marine biomonitoring. Furthermore, Cu concentrations combined with isotope compositions yield site-specific fingerprints allowing geographic discrimination among oysters. This two-dimensional Cu signature is promising as a tool for seafood traceability. [Display omitted] • The first large-scale analysis of Cu stable isotope ratios in oysters is presented. • Bioaccumulation of anthropogenic Cu shift isotope ratios of oysters' soft tissues. • Isotope biomonitoring indicates temporal trends in anthropogenic Cu contamination. • Elemental and isotope Cu discriminate geographic origins of oysters. [ABSTRACT FROM AUTHOR]

The Covid-19 outbreak had a critical impact on a massive amount of human activities as well as the global health system. On the other hand, the lockdown and related suspension of working activities reduced pollution emissions. The use of biomonitoring is an efficient and quite recent tool to assess environmental pollution through the analysis of a proper bioindicator, such as bees. This study set out to ascertain the impact of the Covid-19 pandemic lockdown on the environmental occurrence of eleven heavy metals in the Campania region (Italy) by analyzing bees and bee products. A further aim of this study was the assessment of the Honeybee Contamination Index (HCI) in three different areas of the Campania region and its comparison with other Italian areas to depict the current environmental pollutants levels of heavy metals. The results showed that the levels of heavy metals bioaccumulated by bees during the pandemic lockdown (T1) were statistically lower than the sampling times after Covid-19 restrictions and the resumption of some or all activities (T2 and T3). A comparable trend was observed in wax and pollen. However, bee, pollen, and wax showed higher levels of Cd and Hg in T1 than T2 and T3. The analysis of the HCI showed a low contamination level of the sampling sites for Cd and Pb, and an intermediate-high level as regards Ni and Cr. The biomonitoring study highlighted a decrease of heavy metals in the environmental compartments due to the intense pandemic restrictions. Therefore, Apis mellifera and other bee products remain a reliable and alternative tool for environmental pollution assessment. [Display omitted] • Environmental pollution by heavy metals was assessed through bees and their products. • The Covid-19 pandemic lockdown led to a decrease in the levels of metals. • Bees are a reliable tool for the environmental quality assessment. • Metals levels in three areas of Campania did not differ from other regions of Italy. [ABSTRACT FROM AUTHOR]

The application of bioavailability-based risk assessment for the management of contaminated sediments requires new techniques to rapidly and accurately determine metal bioavailability. Here, we designed a multimetal isotopically modified bioassay to directly measure the bioavailability of different metals by tracing the change in their isotopic composition within organisms following sediment exposure. With a 24 h sediment exposure, the bioassay sensed significant bioavailability of nickel and lead within the sediment and determined that cadmium and copper exhibited low bioavailable concentrations and risk profiles. We further tested whether the metal bioavailability sensed by this new bioassay would predict the toxicity risk of metals by examining the relationship between metal bioavailability and metal toxicity to chironomid larvae emergence. A strong dose-toxicity relationship between nickel bioavailability (nickel assimilation rate) and toxicity (22 days emergence ratio) indicated exposure to bioavailable nickel in the sediment induced toxic effects to the chironomids. Overall, our study demonstrated that the isotopically modified bioassay successfully determined metal bioavailability in sediments within a relatively short period of exposure. Because of its speed of measurement, it may be used at the initial screening stage to rapidly diagnose the bioavailable contamination status of a site.

Metal release into the environment from anthropogenic activities may endanger ecosystems and human health. However, identifying and quantifying anthropogenic metal bioaccumulation in organisms remain a challenging task. In this work, we assess Cu isotopes in Pacific oysters (C. gigas) as a new tool for monitoring anthropogenic Cu bioaccumulation into marine environments. Arcachon Bay was taken as a natural laboratory due to its increasing contamination by Cu, and its relevance as a prominent shellfish production area. Here, we transplanted 18-month old oysters reared in an oceanic neighbor area into two Arcachon Bay mariculture sites under different exposure levels to continental Cu inputs. At the end of their 12-month long transplantation period, the oysters' Cu body burdens had increased, and was shifted toward more positive δ65Cu values. The gradient of Cu isotope compositions observed for oysters sampling stations was consistent with relative geographic distance and exposure intensities to unknown continental Cu sources. A binary isotope mixing model based on experimental data allowed to estimate the Cu continental fraction bioaccumulated in the transplanted oysters. The positive δ65Cu values and high bioaccumulated levels of Cu in transplanted oysters support that continental emissions are dominantly anthropogenic. However, identifying specific pollutant coastal source remained unelucidated mostly due to their broader and overlapping isotope signatures and potential post-depositional Cu isotope fractionation processes. Further investigations on isotope fractionation of Cu-based compounds in an aqueous medium may improve Cu source discrimination. Thus, using Cu as an example, this work combines for the first time a well-known caged bivalve approach with metal stable isotope techniques for monitoring and quantifying the bioaccumulation of anthropogenic metal into marine environments. Also, it states the main challenges to pinpoint specific coastal anthropogenic sources utilizing this approach and provides the perspectives for further studies to overcome them. [Display omitted] • Cu isotopes in transplanted oysters were used for monitoring Cu bioaccumulation in a marine environment. • 18-month old oysters were transplanted into Cu-contaminated French mariculture sites. • Oysters have their Cu isotope compositions shifted toward more positive values after a one-year exposure period. • A binary isotope model allowed quantifying the bioaccumulation of anthropogenic Cu. • This approach is an alternative to marine sites with unavailable sample banks of costly environmental monitoring networks. [ABSTRACT FROM AUTHOR]

Biofouling causes major functional and economic problems for aquaculture due to their settlement and subsequent growth on fish-cage netting. As biofouling management is an economic and environmental issue, feasible management practices are clearly required to balance industries and environmental requirements. The most frequent way to control biofouling in aquaculture is by applying Cu-based antifouling paints on fish nets to prevent the undesired growth of biofouling. The most important fish species employed in marine fish farming are cultivated with knotted nylon and ultra-high-molecular-weight polyethylene (UW-polyethylene) nettings. In this study, we examined the effects of two commercial Cu coatings and two manufactured net materials (nylon and UW-polyethylene) on biofouling biomass, community structure, Cu bioaccumulation and the metal composition of fouling assemblages in order to provide farmers with a tool to help reduce the environmental impact of the biocide employed for coating nets. The MDS ordination of the samples coated with both paints on nylon and UW-polyethylene nets showed a gradual modification of community structure associated with rising Cu concentrations. The PCA analysis indicated that the ordination of trace element composition of biofouling varied between concentrations and nets in both paints. The experiments revealed that the fouling biomass decreased following negative exponential regression with an increasing Cu concentration. The increase in fouling biomass with reduced Cu bioaccumulation was greater in nylon than in UW-polyethylene nets. In the nylon nets, the median bioaccumulation on nets (Cu F-50) rose with an 0.75- to 0.82-fold increase in the basal biomass. Conversely, biomass increased 0.50- to 0.63-fold the basal or minimum fouling biomass with a full antifouling paint concentration (B 0) when Cu F-50 was calculated in the UW-polyethylene nets. These results suggest that similar reductions in bioaccumulated Cu in both nets could be achieved without sacrificing excessive fouling biomass increases. [ABSTRACT FROM AUTHOR]