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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.

[Display omitted] • Safe fish in Samsun's Lagoon Lakes with PTE levels within limits. • Minimal health risks from consumption suggested low noncarcinogenic risks. • Pollution sources identified as residential waste, lithogenic, agriculture. • Esox lucius nutritionally superior, rich in essential nutrients. This study is the first comprehensive investigation into the levels of potentially toxic elements (PTEs) in the muscle tissues of various fish species (Carassius gibelio , Squalis cephalus , Esox lucius , and Tinca tinca) in Lagoon Lakes Akgöl and Semenit (LLAS), Samsun, Türkiye. A multidisciplinary approach was employed, integrating elemental analysis, health risk assessment, and source identification techniques to evaluate the distribution, sources, and health risks of PTE contamination in fish. The mean concentrations of toxic and trace elements (µg/kg) were determined in ascending order: Cd (5) < Co (8) < Cr (18) = Pb (18) < Ni (66) < As (1 6 3) < Cu (2 9 0) < Mn (7 9 8) < Fe (6150) < Zn (6250). In contrast, the concentrations of macro elements are provided in units of mg/kg, as follows: Mg (3 9 1) < Na (6 7 7) < Ca (1698) < P (2314) < K (3837), with notable variations across species. Health risk assessment methodologies indicated that PTE levels in fish muscle tissues generally fell below regulatory limits, indicating their safety for consumption. Noncarcinogenic risk assessment further documented the safety of consuming these fish species, with elevated maximum safe consumption quantity (MSCQ) values observed for all metals. In addition, the estimated daily intake of PTEs was found to be below reference doses, confirming the safety of consumption. Esox lucius demonstrated a highest abundance of essential nutrients (e.g., Ca, K, Mg, and P). Source identification techniques indicated that residential waste, lithogenic materials, and agricultural practices are significant contributors to PTE contamination. Overall, this research stresses the importance of monitoring PTE levels in fish, ensuring food safety and protect human health. [ABSTRACT FROM AUTHOR]

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.

Heavy metal pollution in aquatic habitats can be detrimental to both prey and predators in a food web. To investigate the potential for bio-transfer and bioaccumulation of heavy metals between specific trophic levels, 3rd instar larvae of Aedes aegypti were exposed to mercury (Hg), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) for three consecutive generations and fed to dragonfly (Tramea cophysa) nymphs. Exposure to Hg caused the highest mortality in A. aegypti larvae and T. cophysa nymphs. Bioaccumulation and life-history parameters of A. aegypti, including egg hatching time, larval and pupal duration, male and female life span, and fecundity, were also evaluated after metals exposure. All life-history parameters except larval duration were significantly affected by heavy metal treatments. Bioaccumulation of metals in A. aegypti larvae and adults gradually and significantly increased from 1st to 3rd generation. To the best of our knowledge, this is the first study describing the acute toxicity of heavy metals to mosquitoes. Our study shows that heavy metals cause dietary toxicity to an aquatic predator, dragonfly, via trophic transfer, which could have considerable consequences on aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Urban wastewater contains various detergents, pesticides, pharmaceutical medications, cosmetics, hygiene products, and heavy metals. Discharge of municipal sewage into surface water affects the health of aquatic organisms through altering biochemical markers and accumulating heavy metals in various tissues. The present study aimed to evaluate the toxic effects of municipal sewage on the biochemical markers and bioaccumulation of cadmium and lead in freshwater snail (Galba truncatula) during 14 days. Concentrations of toxic metals in the snails were determined using ICP-OES-PerkinElmer, and biochemical parameters were measured via UV-Vis spectroscopy. The results indicated significantly lower levels of glycogen and total antioxidant in the cells, as well as the significantly lower activities of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, acetylcholine esterase, catalase, and glucose-6-phosphate dehydrogenase in the Galba truncatula exposed to sewage compared to the control. However, the activities of lactate dehydrogenase ,glutathione peroxidase, and malondialdehyde were significantly higher in the snails exposed to sewage compared to the control. Moreover, bioaccumulation of cadmium and lead was observed to increase in the experimental groups exposed to sewage. Alterations in biochemical parameters in the G. truncatula exposed to sewage could be due to the toxic effects of various environmental pollutants in municipal wastewater. According to the findings, oxidative damage to the vital tissues of G. truncatula was associated with the bioaccumulation of cadmium and lead, depletion of total antioxidant levels, changes in biochemical parameters, and lipid peroxidation in soft tissues.

Due to the increasing consumption of platinum (Pt), especially in automobile exhaust catalysts, environmental concentrations of Pt are of emerging concern worldwide. Limited information exists on environmental concentrations, particularly in Pt mining regions, while South Africa is the world's main supplier of Pt. Moreover, other metals are also released as by-products of Pt mining, which might also cause environmental concern. Certain fish parasite taxa have the ability to accumulate metals orders of magnitude higher than their hosts and can be used to reliably detect metals with naturally low abundance. Studies on Pt accumulation in parasite-host systems are limited. Therefore, the aims of the present study were (1) to determine the accumulation of a variety of metals (cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), platinum (Pt), and zinc (Zn)) in helminth fish parasites compared with their hosts from a reference site and an impoundment impacted by Pt mining activities; (2) to assess whether there is a difference between bioaccumulation of metals in infected and uninfected hosts, as well as between hosts with different infection intensities; and (3) to compare the biomarker responses (acetylcholine esterase activity (AChE), metallothionein content (MT), catalase activity (CAT), reduced glutathione content (GSH), malondialdehyde content (MDA), protein carbonyls induction (PC), superoxide dismutase activity (SOD), and cellular energy allocation (CEA)) between infected and uninfected hosts. The cestode Atractolytocestus huronensis accumulated significantly higher concentrations of Cr, Ni, and Pt than their host Cyprinus carpio, while the nematode Contracaecum sp. accumulated significantly higher concentrations of Pt and Zn than their host Clarias gariepinus. Infected fish showed lower metal concentrations compared to uninfected fish, while the parasites had no significant effects on their hosts' biomarker responses. The parasites demonstrated the bioavailability of metals derived from Pt mining activities and their ability to resist its toxic effects. Thus, these parasites are promising sensitive accumulation indicators for Cr, Ni, Pb, and Pt contaminations from Pt mining activities. [ABSTRACT FROM AUTHOR]

Metal accumulation by Spirulina platensis from synthetic effluents with the following chemical composition: Cr/Fe, Cr/Fe/Ni, Cr/Fe/Ni/Zn, and Cr/Fe/Ni/Zn/Cu during repeated cultivation cycle was investigated. Metal ions in different concentrations were added to the culture medium at the exponential and stationary phases of biomass growth and their uptake by biomass was traced using neutron activation analysis. The effect of metal ions on biomass and main biochemical components (proteins, carbohydrates, lipids, phycobilins, and β-carotene) was monitored. S. platensis keeps high metal accumulation capacity during 2–3 cultivation cycles, while the metal ions were added in the stationary phase of its growth. By adding metals in the exponential phase of growth in the following concentrations: 10 mg/L of chromium (VI), 5 mg/L of iron, 2 mg/L of zinc, nickel, and copper, Spirulina platensis acted as renewable accumulator only in Cr/Fe system. It maintained the accumulation capacity during three cultivation cycles when exposed to lower concentrations of metal ions. Its ability to accumulate metal ions during several cultivation cycles was ensured by the maintenance of the optimal level of proteins and lipid in biomass. [ABSTRACT FROM AUTHOR]

The application of sewage sludge (SS) in agriculture is a wastewater recycling method for soil fertilization. The aim of this study was to assess the influences of SS amendment rates (0, 10, 20, 30, 40 and 50 g kg-1) on the green-salad leafy plant Eruca sativa. The SS amendment increased soil salinity and organic matter and decreased soil pH. The heavy metal (HM) contents were below the permissible limits as recommended by the Council of the European Communities. An increase in E. sativa morphometric parameters was detected. The leaf, root and total biomasses of E. sativa increased at amendment rates 10, 20 and 30 g kg-1. The applications of 40 and 50 g kg-1 negatively affected the biomass. The highest concentration of the measured HMs in the plant was detected at the 50 g kg-1 amendment rate. The bioaccumulation factors of Cd, Co, Cr, Fe, Mn, Ni, Pb and Zn were < 1.0, whereas those of Cu and Mo were > 1. The translocation factors for all HMs were < 1.0 except for Cd and Pb. Even though, SS increased the biomass of E. sativa, SS is not recommended as a fertilizer for E. sativa, since translocation factors of Cd and Pb were >1. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the biochemical status of Venerupis decussata collected seasonally from two Tunisian coastline lagoons (Ghar El Melh and Boughrara) submitted to different anthropogenic levels. Trace elements were significantly higher in clams from Boughrara, especially during the warm season. Fatty acids, proximate compositions, and nutritional value of both clam populations were higher, appearing to be the best for human consumption principally during the spring season. The principal component analysis was determined, including phospholipids and reserve lipids, revealing a great variation with the exogenous and endogenous factors. Generally, clams from Boughrara had a significant alteration in biochemical composition principally due to the anthropogenic levels and physicochemical fluctuation of this lagoon. Our results reflected the healthy benefit of clam consumption and the use of energy reserves and essential fatty acids as a great biomarker to assess ecological risk in lagoons and other coastal ecosystems. [ABSTRACT FROM AUTHOR]

Metallothioneins (MTs) are a family of low molecular weight, cysteine-rich, metal-binding proteins, which play important roles in metal homeostasis and heavy metal detoxification. In our previous study, a novel full length MT cDNA was successfully cloned from the freshwater crab (Sinopotamon henanense). In the present study, tandem repeats of two and three copies of the crab MT gene were integrated by overlap extension PCR (SOE-PCR) and expressed in Escherichia coli. The SUMO fusion expression system was adopted to increase the stability and solubility of the recombinant MT proteins. The recombinant proteins were purified and their metal-binding abilities were further analyzed by the ultraviolet absorption spectral scan. Furthermore, the metal tolerance and bioaccumulation of E. coli cells expressing oligomeric MTs were determined. Results showed that the recombinant plasmids pET28a-SUMO-2MT and pET28a-SUMO-3MT were successfully constructed. SDS-PAGE analysis showed that the SUMO-2MT and SUMO-3MT were expressed mainly in the soluble forms. Oligomeric MTs expression significantly enhanced Cu, Cd or Zn tolerance and accumulation in E. coli in the order: SUMO-3MT˃SUMO-2MT˃SUMO-MT˃control. Cells harboring pET28a-SUMO -3MT exhibited the highest Cu, Cd or Zn bioaccumulation at 5.8-fold, 3.1-fold or 6.7-fold higher than that of the control cells. Our research could lay a foundation for large-scale preparation of MTs and provide a scientific basis for bioremediation of heavy metal pollution by oligomeric MTs. • Tandem oligomeric expression of crab metallothionein enhance heavy metal tolerance and bioaccumulation in Escherichia coli. [ABSTRACT FROM AUTHOR]

There is a growing conservation concern about the possible consequences of environmental contamination in the health of bat communities. Most studies on the effects of contaminants in bats have been focused on organic contaminants, and the consequences of bat exposure to metals and metalloids remain largely unknown. The aim of this study was to evaluate the suitability of external biological matrices (fur and wing membrane) for the assessment of exposure and bioaccumulation of metals in bats. The concentration of arsenic, cadmium, cobalt, chromium, copper, manganese, nickel, lead, selenium and zinc was measured in internal organs (liver, heart, brain), internal (bone) and external tissues (wing membrane, fur) collected from bat carcasses of four species (Hypsugo savii , Nyctalus leisleri , Pipistrellus pipistrellus , Pipistrellus pygmaeus) obtained in windfarm mortality searches. With the exception of zinc (P = 0.223), the results showed significant differences between the concentrations of metals in the analyzed tissues for all metals (P < 0.05). Significant differences were also found between organs/tissues (P < 0.001), metals (P < 0.001) and a significant interaction between organs/tissues and metals was found (P < 0.001). Despite these results, the patterns in terms of metal accumulation were similar for all samples. Depending on the metal, the organ/tissue that showed the highest concentrations varied, but fur and wing had the highest concentrations for most metals. The variability obtained in terms of metal concentrations in different tissues highlights the need to define standardized methods capable of being applied in monitoring bat populations worldwide. The results indicate that wing membrane and fur, biological matrices that may be collected from living bats, yield reliable results and may be useful for studies on bats ecotoxicology, coupled to a standardized protocol for large-scale investigation of metal accumulation. Image 1 • Internal and external samples were used to assess metal accumulation in bats. • Metal concentrations measured depended on the tissue/organ analyzed. • Wing membrane and fur had the highest metal concentrations for most metals. • Wing membrane can be a proxy for metal concentrations in internal organs. • External biological matrices are the best option for studies on wildlife ecotoxicology. Wing membrane and fur are reliable biological matrices for studies on bats ecotoxicology, being useful to measure bat's exposure to metals/metalloids. [ABSTRACT FROM AUTHOR]

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]

The natural regeneration of forests in mining areas is typically hampered by edaphic stress. Semiarid conditions add a climatic stress that challenges the restoration of these harsh ecosystems. This is the case of Tetraclinisarticulata (Vahl) Masters mixed forests in the Western Mediterranean region colonizing mining structures abandoned three decades ago. We studied the factors controlling the natural establishment of nine shrub and tree species key in these forests in eight metal mine tailings in SE Spain. In addition, we assessed the success of reintroducing 1480 individuals of the nine species 15 months after planting in one of the tailings. Specifically, we analyzed the effect of (i) species identity in terms of sapling survival, growth, nutritional status and metal bioaccumulation, and (ii) adding organic amendments into the planting holes on the same parameters. Our results indicated that natural colonization is a recent process, with seedling cohorts that vary up to two orders of magnitude among species and a practical absence of adult plants in most species excepting T. articulata. We identified seed limitation as a key factor controlling seedling density, which was significantly explained by the distance from the border of the tailing to the closest adult out of the tailing. Soil metal concentration did not have any explanatory power on the density of naturally-established seedlings, whereas soil fertility was relevant only for Rhamnus lycioides L. Overall survival of planted individuals was over 80%, survival and growth remarkably differing among species. Organic amendments had neutral or negative effects on plant survival, but significantly increased the growth of survivors despite their modest effects on leaf nutrient contents. Most species showed high metal bioaccumulation, which was exacerbated by organic amendments. We discuss how biodiversity conservation programs can benefit from the affordable and successful plantation of stress-tolerant local species, but come at the expense of potential metal transfer through trophic webs.

The main goal of the study was to evaluate the avoidance behaviour of isopods (Porcellio scaber) to food or soil contaminated with different nanoparticles (NPs): Ag-NPs, sulfidized Ag-NPs (Ag 2 S-NPs) or CeO 2 -NPs. These NPs are characterized by different physiochemical properties, and antimicrobial and toxic potentials. Isopods were exposed in three scenarios: (i) 14 d feeding test where animals were fed solely on contaminated leaves; (ii) 14 d food selection test where leaves spiked with NPs were offered simultaneously with uncontaminated leaves; and (iii) 48 h soil avoidance test where animals could choose between uncontaminated and soil spiked with NPs. The isopods decreased feeding on Ag-NP contaminated food and clearly avoided contact with Ag-NP contaminated soil. Substantial accumulation of Ag in the body of isopods was found both in feeding and food selection test. This means that food selection might mitigate but could not prevent Ag accumulation in woodlice. In contrast, no such behavioural response of isopods was found for CeO 2 -NP. These data suggest that the presence of metal ions in the case of Ag-NPs may be the main reason for differential behaviour. Interestingly, moderate avoidance behaviour was observed also towards Ag 2 S-NPs although no Ag+ was detected in stock suspensions. This avoidance was not statistically significant and needs to be further explored. Behavioural test with isopods showed again their value in estimation of potential adverse effects of pollutants comparable to collembolans and earthworms. • Isopods evidently avoided food or soil treated with Ag-NPs. • Discrimination of food or soil contaminated with CeO2 was not prominent. • Food selection might mitigate but could not prevent Ag accumulation in isopods. • Avoidance test with isopods is a good tool to evaluate the contamination of soil. [ABSTRACT FROM AUTHOR]

Accumulation of 17 elements in muscle and liver of common nase and vimba bream, caught between February and May 2016 in the Danube River (1173 river kilometer), were assessed by ICP-OES. The principal component analysis grouped muscle and liver samples based on element concentrations (muscle grouped by higher Ba and Sr values, and liver grouped by higher Al, B, Cd, Cr, Cu, Fe, Mn, and Zn values), but no grouping between the two species was observed. Concentrations of Ba, Cu, Fe, and Zn were significantly higher in muscle, and concentrations of Ba, Cd, Cu, and Mn in liver of common nase, while vimba bream had significantly higher concentrations of Cr and Fe in liver. Common nase has a higher affinity for bioaccumulation of Cu, Fe, and Zn in muscle, while vimba bream has a higher affinity for Al, Cd, and Cr in muscle. [ABSTRACT FROM AUTHOR]

Abstract Protamine-like proteins (PL-II, PL-III and PL-IV) represent the major basic nuclear component of Mytilus galloprovincialis L sperm chromatin. The present study investigates the effects induced on the properties of PL-II protein after exposure of Mytilus galloprovincialis L for 24 h to 1.5 and 5 µM CdCl 2. We found cadmium accumulation in protamine-like proteins with a linear grow up with the exposition dose. In particular, after 5 µM CdCl 2 mussels exposure, the mobility of PL-II band changed in SDS-PAGE, suggesting structural rearrangement in presence of cadmium. Structural analysis using fluorescent probes, indicated that at 5 µM CdCl 2 the complete conformational change of PL-II protein was reached. In the same condition of mussels exposure of 5 µM CdCl 2 , PL-II protein changed its DNA binding mode, which determined a closer DNA binding, because higher amount of NaCl were required for PL-II protein release by sperm nuclei. These results supported the hypothesis that mussel exposure to this CdCl 2 dose, although lower to toxic ones, affects the properties of this protein and as a consequence chromatin organization of spermatozoa that is essential for the success of fertilization. Highlights • Mytilus galloprovincialis L. is an usefull model organism for heavy metals biomonitoring. • Cadmium accumulates in protamine-like proteins. • 5 µM CdCl 2 mussels exposure produces protamine-like-II protein conformational changes. • 5 µM CdCl 2 mussels exposure changes protamine-like-II protein DNA binding mode. [ABSTRACT FROM AUTHOR]

Abstract Bioaccumulation of toxic metal elements including mercury (Hg) can be highly variable in marine fish species. Metal concentration is influenced by various species-specific physiological and ecological traits, including individual diet composition and foraging habitat. The impact of trophic ecology and habitat preference on Hg accumulation was analyzed through total Hg concentration and stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) in the muscle of 132 fish belonging to 23 different species from the Senegalese coast (West Africa), where the marine ecosystem is submitted to nutrient inputs from various sources such as upwelling or rivers. Species-specific ecological traits were first investigated and results showed that vertical (i.e. water column distribution) and horizontal habitat (i.e. distance from the coast) led to differential Hg accumulation among species. Coastal and demersal fish were more contaminated than offshore and pelagic species. Individual characteristics therefore revealed an increase of Hg concentration in muscle that paralleled trophic level for some locations. Considering all individuals, the main carbon source was significantly correlated with Hg concentration, again revealing a higher accumulation for fish foraging in nearshore and benthic habitats. The large intraspecific variability observed in stable isotope signatures highlights the need to conduct ecotoxicological studies at the individual level to ensure a thorough understanding of mechanisms driving metal accumulation in marine fish. For individuals from a same species and site, Hg variation was mainly explained by fish length, in accordance with the bioaccumulation of Hg over time. Finally, Hg concentrations in fish muscle are discussed regarding their human health impact. No individual exceeded the current maximum acceptable limit for seafood consumption set by both the European Union and the Food and Agriculture Organization of the United Nations. However, overconsumption of some coastal demersal species analyzed here could be of concern regarding human exposure to mercury. Graphical abstract Unlabelled Image Highlights • THg, δ13C, δ15N were determined in 132 marine fish from a tropical coastal region. • Coastal and demersal species were more contaminated than oceanic and pelagic ones. • SIA suggest that Hg exposure derived from bottom feeding and/or in estuarine waters. • Conspecific fish fed on different coastal food webs and Hg increased with fish size. • Hg levels in fish from Senegal were not of concern for human consumption. [ABSTRACT FROM AUTHOR]

Abstract The recently developed modelling tool MERLIN-Expo was applied to support the exposure assessment of an aquatic food web to trace metals in a coastal environment. The exposure scenario, built on the data from Daliao River estuary in the Liaodong Bay (Bohai Sea, China), affected by long-term and large-scale industrial activities as well as rapid urbanization in Liao River watershed, represents an interesting case-study for ecological exposure modelling due to the availability of local data on metal concentrations in water and sediment. The bioaccumulation of selected trace metals in aquatic organisms was modelled and compared with field data from local aquatic organisms. Both model results and experimental data demonstrated that As, Cd, Cu, Ni, Pb and Zn, out of examined metals, were accumulated most abundantly by invertebrates and less by higher trophic level species. The body parts of the sampled animals with the highest measured concentration of metals were predominantly muscles, intestine and liver and fish skin in the case of Cr. The Morris and extended Fourier Analysis (EFAST) were used to account for variability in selected parameters of the bioaccumulation model. Food assimilation efficiency and slopes and intercepts of two sub-models for calculating metal specific BCFs (BCF metal -exposure concentration) and fish weight (Weight fish -Length fish) were identified as the most influential parameters on ecological exposure to selected metals. Highlights • Ecological exposure to As, Cd, Cu, Ni, Pb, Zn was assessed for Liaodong Bay. • MERLIN-Expo was applied to model metal bioaccumulation in aquatic species. • As, Cd, Cu, Ni, Pb and Zn accumulate mostly in invertebrates. • Good agreement between simulated and observed data was noted. • Sensitivity of modelled results were analysed using the Morris and EFAST techniques. [ABSTRACT FROM AUTHOR]

Cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) concentrations in the liver and the quadriceps muscle of adult stone marten (9 specimens) and pine marten (11 specimens) from Central Italy were assessed. No significant difference in the heavy metal values for each of the two selected tissues was detected for the two mustelid species. The measured heavy metal values were generally below the contamination level ranges from other areas of Central Italy and Croatia, except for the Cd in this latter area. Toxic Contamination Index (TCI) values for Cd showed high contamination levels both in the stone marten (most synanthropic species, colonizing mainly suburban environments) and in pine marten (species less adaptable to the anthropic environments, colonizing mainly rural and forest environments). High TCI values for Pb were detected only in stone marten. This fact indicates a higher Pb contamination in suburban habitats, probably due to the past use of leaded gasoline and still currently released by several anthropogenic activities, as the industrial emissions of mineral processing and incinerators, making Pb one of the most common heavy metal contaminant in soils. The present study suggests that stone marten and pine marten can be good bioindicators with a complementary role regarding the evaluation of the heavy metal contamination in a given territory. When high levels of TCI (in our case for Cd) are detectable in selected tissues of both stone marten and pine marten, it means that we are in the presence of widespread pollution. On the other hand, when this condition is observed only for stone marten (in our case for Pb), it means that we are in the presence of a local contamination mainly localized in areas with high anthropization. [ABSTRACT FROM AUTHOR]