Investigation of dissolved organic matter's influence on the toxicity of cadmium to the cyanobacterium Microcystis aeruginosa by biochemical and molecular assays.

Rapid economic development has increased the accumulation of dissolved organic matter (DOM) and heavy metals in aquatic environments. In addition, Microcystis aeruginosa can cause the outbreak of cyanobacteria bloom and can produce microcystin, which poses a threat to human water safety. Therefore, this study analyzed the biochemical and molecular assays of DOM (0, 1, 3, 5, 8, 10 mg C L-1) extracted from four different sources on the toxicity of cadmium (Cd) to M. aeruginosa. The results showed that the addition of different concentrations of DOM from sediment, biochar, and humic acid alleviated the toxicity of Cd to M. aeruginosa. But the addition of rice hulls DOM at high concentrations (8 and 10 mg L-1) significantly reduced the normal growth and metabolic activities of M. aeruginosa. DOM from four different sources promoted the expression level of microcystin-related gene mcyA and the production of microcystin-leucine-arginine (MC-LR), and mcyA was positively correlated with MC-LR. DOM from biochar, sediment, and humic acid were able to bind Cd through complexation. The results will help to understand the toxic effects of heavy metals on toxic-producing cyanobacteria in the presence of DOM, and provide certain reference for the evaluation of water environmental health.

Heavy metals assessment of ecosystem polluted with wastewaters and taxonomic profiling of multi-resistant bacteria with potential for petroleum hydrocarbon catabolism in nitrogen-limiting medium.

The coexistence of heavy metals (HMs) and petroleum hydrocarbons (PHs) exacerbates ecotoxicity and impair the drivers of eco-functionalities that stimulate essential nutrients for the productivity of the impacted environment. Profiling the bacteria that stem the ecological impact via HMs sequestration and PHs catabolism with nitrogen fixation is imperative to bioremediation of the polluted sites. The sediment of site that was consistently contaminated with industrial wastewaters was analysed for ecological toxicants and the bacterial strains that combined HMs resistance with PHs catabolism in a nitrogen-limiting system were isolated from the sediment and characterized. The geochemistry of the samples revealed the co-occurrence of the above-benchmark concentrations of HMs with the derivatives of hydrocarbons. Notwithstanding, nickel and mercury (with 5% each of the total metal concentrations in the polluted site) exhibited probable effect concentrations on the biota and thus hazardous to the ecosystem. Approx. 31% of the bacterial community, comprising unclassified Planococcaceae, unclassified Bradyrhizobiaceae, Rhodococcus, and Bacillus species, resisted 160 µmol Hg2+ in the nitrogen-limiting system within 24 h post-inoculation. The bacterial strains adopt volatilization, and sometimes in combination with adsorption/bioaccumulation strategies to sequester Hg2+ toxicity while utilizing PHs as sources of carbon and energy. Efficient metabolism of petroleum biomarkers (> 87%) and Hg2+ sequestration (≥ 75% of 40 µmol Hg2+) displayed by the selected bacterial strains portend the potential applicability of the bacilli for biotechnological restoration of the polluted site.

Phytoremediation of industrial effluents assisted by plant growth promoting bacteria.

Industrialization plays a crucial role in the economic development of a country; however, the effluents produced as a byproduct generally contain toxic substances which are detrimental to living organisms. In this regard, it is essential to treat these toxic effluents before exposing them to the natural environment by selecting the most appropriate method accordingly. Several techniques are used to remediate industrial effluents including physical, chemical, and biological. Although some physical and chemical remediation technologies are of substantially important in remediation of industrial effluents, however, these technologies are either expensive to be applied by developing countries or not suitable for remediation of all kinds of effluents. In contrast, biological remediation is cost effective, nature friendly, and easy to use for almost all kinds of effluents. Among biological remediation strategies, phytoremediation is considered to be the most suitable method for remediation of industrial effluents; however, the phytoremediation process is slow, takes time in application and some effluents even affect plants growth and development. Alternately, plant microbe interactions could be a winning partner to remediate industrial effluents more efficiently. Among the microbes, plant growth promoting bacteria (PGPB) not only improve plant growth but also help in degradation, sequestration, volatilization, solubilization, mobilization, and bioleaching of industrial effluents which subsequently improve the phytoremediation process. The current study discusses the role of PGPB in enhancing the phytoremediation processes of industrial effluents.

Heavy metal contents in salted fish retailed in Egypt: Dietary intakes and health risk assessment.

Background: In Egypt, salted fish is considered a typically processed fish, including salted sardine, salted mullet (feseikh), keeled mullet (sahlia), and herrings. High-quality protein, polyunsaturated fatty acids, vital amino acids, and trace minerals such as magnesium and calcium are all abundant in fish. However, eating salted fish can expose people to toxins found in the environment, such as heavy metals. Aim: In Zagazig, Egypt, four types of locally produced salted fish-salted sardine, feseikh, sahlia, and herrings-were tested for heavy metals, specifically lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg). Second, the assessed heavy metals linked to the Egyptian population's consumption of salted fish were used to calculate estimated daily intakes (EDIs) and potential health hazards, such as hazard quotient (HQ) and hazard index (HI). Methods: Samples of salted herrings, feseikh, sahlia, and sardines were gathered from the markets in Zagazig. Samples of salted fish were subjected to acid digestion and then heavy metal extraction. Atomic absorption spectrometers (AAS) were used to measure heavy metals. HI, HQ, and EDI were computed computationally. Results: With the exception of mercury, which was not found in the salted herrings, the recorded results showed that all of the tested metals were present in the samples that were evaluated. The herrings contained residual Pb and Cd contents that were highest, followed by sardine, feseikh, and sahlia, in that order. After sardine, herrings, and sahlia, feseikh has the greatest concentration. Sardine, feseikh, and sahlia had the highest quantities of mercury, in that order. A number of samples were found to be above the maximum allowable levels. There were no apparent hazards associated with consuming such conventional fish products, according to the computed HQ and HI values for the heavy metals under investigation based on the daily intakes. Conclusion: Samples of salted fish sold in Zagazig, Egypt, had high quantities of the hazardous elements Pb, Cd, As, and Hg. Due to the bioaccumulation and biomagnification characteristics of these studied metals, such data should be taken carefully even though the computed health hazards revealed no potential problems.

Assessment of the biological effect of metal ions and their complexes using Allium cepa and Artemia salina assays: a possible environmental implementation of biological inorganic chemistry.

The pollution of aquatic ecosystems due to the elevated concentration of a variety of contaminants, such as metal ions, poses a threat to humankind, as these ecosystems are in high relevance with human activities and survivability. The exposure in heavy metal ions is responsible for many severe chronic and pathogenic diseases and some types of cancer as well. Metal ions of the groups 11 (Cu, Ag, Au), 12 (Zn, Cd, Hg), 14 (Sn, Pb) and 15 (Sb, Bi) highly interfere with proteins leading to DNA damage and oxidative stress. While, the detection of these contaminants is mainly based on physicochemical analysis, the chemical determination, however, is deemed ineffective in some cases because of their complex nature. The development of biological models for the evaluation of the presence of metal ions is an attractive solution, which provides more insights regarding their effects. The present work critically reviews the reports published regarding the toxicity assessment of heavy metal ions through Allium cepa and Artemia salina assays. The in vivo toxicity of the agents is not only dose depended, but it is also strongly affected by their ligand type. However, there is no comprehensive study which compares the biological effect of chemical agents against Allium cepa and Artemia salina. Reports that include metal ions and complexes interaction with either Allium cepa or Artemia salina bio-indicators are included in the review.

Removal of toxic heavy metals using genetically engineered microbes: Molecular tools, risk assessment and management strategies.

The direct release of industrial effluent into the water and other anthropogenic activities causes water pollution. Heavy metal ions are the primary contaminant in the industrial effluents which are exceptionally toxic at low concentrations, terribly disturb the endurance equilibrium of activities in the eco-system and be remarkably hazardous to human health. Different conventional treatment methodologies were utilized for the removal of toxic pollutants from the contaminated water which has several drawbacks such as cost-ineffective and lower efficiency. Recently, genetically modified micro-organisms (GMMs) stand-out for the removal of toxic heavy metals are viewed as an economically plausible and environmentally safe technique. GMMs are microorganisms whose genetic material has been changed utilizing genetic engineering techniques that exhibit enhanced removal efficiency in comparison with the other treatment methodologies. The present review comments the GMMs such as bacteria, algae and fungi and their potential for the removal of toxic heavy metals. This review provides current aspects of different advanced molecular tools which have been used to manipulate micro-organisms through genetic expression for the breakdown of metal compounds in polluted areas. The strategies, major limitations and challenges for genetic engineering of micro-organisms have been reviewed. The current review investigates the approaches working on utilizing genetically modified micro-organisms and effective removal techniques.

Review: Mytilus galloprovincialis: An essential, low-cost model organism for the impact of xenobiotics on oxidative stress and public health.

The level of pollution becomes more and more of a pressuring matter for humankind at a worldwide level. Often the focus is on the effects that we can directly and see such as decreased air quality and higher than normal temperatures and weather, but the effects we cannot see are frequently overlooked. For at least the past decade increasing importance has been given towards the effects of pollution of living animals or non-target organisms and plants. For this purpose, one model animal that surfaced is the purpose, one model animal surfaced is Mytilus galloprovincialis. As all mussels, this species is capable of bio-accumulating important quantities of different xenobiotics such as pesticides, paints, medicines, heavy metals, industrial compounds, and even compounds marketed as antioxidants and antivirals. Their toxic effects can be assessed through their impact on oxidative stress, lysosomal membrane stability, and cell viability through trypan blue exclusion test and neutral red retention assay techniques. The purpose of this paper is to highlight the benefits of using M. galloprovincialis as an animal model for toxicological assays of various classes of xenobiotics by bringing to light the studies that have approached the matter.

Reduction of Hexavalent Chromium [Cr(VI)] by Heavy Metal Tolerant Bacterium Alkalihalobacillus clausii CRA1 and Its Toxicity Assessment Through Flow Cytometry.

A chromate-resistant bacterial strain was isolated from tannery effluent; based on morphological, biochemical, and 16S rRNA gene sequencing, it was identified as Alkalihalobacillus clausii and designated A. clausii CRA1. It was found to be halophilic, alkaliphilic, and resistant to multiple heavy metals like Cr(VI), Cd(II), As(II), Pb(II), Ni(II), Hg(II), Cu(II), Zn(II), and Fe(II). The strain was found to reduce 72% of chromate in 6 days in Cr(VI) spiked Luria Bertani medium with unaffected bacterial growth at an initial C(VI) concentration of 50 mg L-1. Chromate reductase activity of culture supernatant (cultivated in LB broth) and cell lysate of the bacterium was found to be 23 and 43U, where 1U is µmol of Cr(VI) reduced/min/mg protein. Flow cytometry studies revealed that no significant effect of Cr(VI) on cell viability was observed till 12 h of exposure at 100, 200, 400 mg L-1 concentrations, indicated by non-significant cell death (propidium iodide positive cells). However, at 800 and 1000 mg L-1 Cr(VI) concentration, toxicity (cell death) was observed after 12 h of exposure. FACs studies also indicated that exposure to Cr(VI) increases cell size and cell granularity, which was also confirmed in SEM and TEM images of Cr(VI) treated cells. The presence of Cr(III) species in EDX spectra of Cr(VI) treated cells confirms that reduction of Cr(VI) to Cr(III) is the primary mechanism of Cr(VI) removal by the bacterium. Therefore, the bacterium A. clausii has potential for application in chromate removal from industrial waste effluents.

Prospective bioremediation of toxic heavy metals in water by surfactant exopolysaccharide of Ochrobactrum pseudintermedium using cost-effective substrate.

Globally, the underlying peril of cumulative toxicity of heavy metals in water bodies contaminated by industrial effluents is a matter of great concern to the environmentalists. Heavy metals like lead, cadmium, and nickel are particularly liable for this. Such toxic water is not only hazardous to human health but also harmful to aquatic animals. Remedial measures are being taken by physico-chemical techniques, but most of them are neither eco-friendly nor cost-effective. Biological means like bioaccumulation of heavy metals by viable bacteria are often tedious. In the present study, biosorption of heavy metals is successfully expedited by surfactant exopolysaccharide (SEPS) of Ochrobactrum pseudintermedium C1 as a simple, safe, and economically sustainable option utilizing an easily available and cost-effective substrate like molasses extract. Its efficacy in bioremediation of toxic heavy metals like cadmium, nickel, and lead have been studied by UV-Vis spectrophotometry and verified by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). FTIR and zeta potential studies have also been carried out to explore this novel biosorption potential. Results are conclusive and promising. Moreover, this particular SEPS alone can remediate all these three toxic heavy metals in water. For futuristic applications, it might be a prospective and cost-effective resource for bioremediation of toxic heavy metals in aqueous environment.

In vivo assessment of bisphenol A induced histopathological alterations and inflammatory gene expression in lungs of male Wistar rats.

Bisphenol A (BPA), an imperative environmental contaminant used in polycarbonate plastics. Due to limited information concerning the effect of BPA on lungs, this study design to assess whether BPA cause alterations in histopathology and trace metal content in lungs of rats. They were divided into five groups with five rats per group. Group I was named as control group. Group L6 and L12 were received BPA (10 mg/kg body weight/day) for 6 weeks and 12 weeks respectively. Group H6 and L12 were given BPA (25 mg/kg body weight/day) for 6 weeks and 12 weeks respectively. Considerable alteration in Cu, Zn and Fe was detected in experimental groups. BPA also caused significant increase in the expression of tumor necrosis factor α that mediate the pulmonary inflammatory response. Comparative study of resolved proteins i.e. 72 KDa (matrix metalloproteinase 2 fragment) and 109 KDa (nucleolin) on SDS-PAGE showed their altered expression in experimental groups. Histopathology of experimental groups revealed altered architecture of lungs. Special staining of BPA treated groups showed significant number of mast cells in alveoli and bronchioles. Prolonged administration of BPA causes deleterious aggravating lung damage even at extremely low dose, so the use of BPA should be prohibited in plastic synthesizing industries.

Analysis of the Genome of the Heavy Metal Resistant and Hydrocarbon-Degrading Rhizospheric Pseudomonas qingdaonensis ZCR6 Strain and Assessment of Its Plant-Growth-Promoting Traits.

The Pseudomonas qingdaonensis ZCR6 strain, isolated from the rhizosphere of Zea mays growing in soil co-contaminated with hydrocarbons and heavy metals, was investigated for its plant growth promotion, hydrocarbon degradation, and heavy metal resistance. In vitro bioassays confirmed all of the abovementioned properties. ZCR6 was able to produce indole acetic acid (IAA), siderophores, and ammonia, solubilized Ca3(PO4)2, and showed surface active properties and activity of cellulase and very high activity of 1-aminocyclopropane-1-carboxylic acid deaminase (297 nmol α-ketobutyrate mg-1 h-1). The strain degraded petroleum hydrocarbons (76.52% of the initial hydrocarbon content was degraded) and was resistant to Cd, Zn, and Cu (minimal inhibitory concentrations reached 5, 15, and 10 mM metal, respectively). The genome of the ZCR6 strain consisted of 5,507,067 bp, and a total of 5055 genes were annotated, of which 4943 were protein-coding sequences. Annotation revealed the presence of genes associated with nitrogen fixation, phosphate solubilization, sulfur metabolism, siderophore biosynthesis and uptake, synthesis of IAA, ethylene modulation, heavy metal resistance, exopolysaccharide biosynthesis, and organic compound degradation. Complete characteristics of the ZCR6 strain showed its potential multiway properties for enhancing the phytoremediation of co-contaminated soils. To our knowledge, this is the first analysis of the biotechnological potential of the species P. qingdaonensis.

Integrative assessment of the ecological risk of heavy metals in a South American estuary under human pressures.

Biomonitoring of heavy metal pollution through the use of biomarkers could be a difficult task since the organisms' physiological changes could shift regarding natural factors (i.e., the season of the year) and due to the anthropogenic pressures of the environment. In the Southwest Atlantic Ocean, where most industrial and developing countries are settled, it is essential to address these concerns to generate information for the stakeholders and monitoring programs that aim to use biochemical biomarkers as early warning signals to detect heavy metal pollution. The present study intended to determinate the heavy metal concentrations in sediments and the hepatopancreas of the crab species Neohelice granulata as well as the ecological risk through the use of biomarkers and geochemical indices in sites with different anthropogenic pressures of the Bahía Blanca estuary (SW Atlantic Ocean) during the warm and cold season. The results showed low to moderate heavy metal pollution in the sediments by Cu with possible effects on the biota in a site with sewage waters' discharges. Except for GST that was explained by Cd, the biomarkers employed were not useful to assess spatial heavy metal pollution, and they might be ruled out by physiological seasonal variations rather than anthropogenic constraints, or another type of pollutants in the area.

Content of toxic metals and As in marine and freshwater fish species available for sale in EU supermarkets and health risk associated with its consumption.

BACKGROUND: The present study investigated Pb, Cd and As concentrations in canned tuna, tuna steak, rainbow trout, smoked mackerel, and Baltic and Atlantic cod, as well as Atlantic salmon. The aim was to spot check the quality of the most commonly purchased types of fish that are available for sale in most common supermarket chains throughout the Poland, as well as to determine potentially less contaminated sources of fish available for retail. A dry ashing digestion protocol followed by inductively coupled plasma mass spectrometry analysis was employed to achieve a better recover of heavy metals and As from fish muscle tissues. RESULTS: The cumulative concentration of metals and As in fish muscle tissue decreases in order: farmed Atlantic salmon > mackerel > Baltic cod > rainbow trout > canned tuna fish > Atlantic cod > yellowfin tuna steak. It was found that canned tuna from Central and Eastern Pacific Ocean were more contaminated than tuna from East and West Indian Ocean, Baltic cod was significantly more contaminated than cod from North-East Atlantic. Smoked mackerel from North-East Pacific Ocean is three times more contaminated than mackerel from Northern North Sea. All fish, except for yellowfin tuna steak, should not be intended for retail because they exceed maximum levels for Cd and Pb. CONCLUSION: Consuming only one serving (140 g) of Baltic cod exposes one to 51% of the daily acceptable Cd intake, while the same portion of canned tuna and smoked mackerel from the Pacific Ocean deliver 69% and 72% of this element respectively. The most cadmium is consumed with smoked mackerel from the North Sea, comprising as much as 162% of the daily acceptable dosage . © 2020 Society of Chemical Industry.

Heavy metal pollution and risk assessment by the battery of toxicity tests.

The current study was carried out on dominant fish Oreochromis niloticus and water collected from the polluted Yamuna River, Agra, India. The heavy metals in water, recorded as follows: Fe > Mn > Zn > Cu > Ni > Cr > Cd and all were found to be above the prescribed limits. According to metal pollution index, exposed muscle (49.86), kidney (47.68) and liver (45.26) have been recorded to have higher bioaccumulation. The blood biochemical analysis of exposed O. niloticus indicated significant increase in activities of aspartate aminotransferase (+ 343.5%), alkaline phosphatase (+ 673.6%), alanine aminotransferase (+ 309.1%), and creatinine (+ 494.3%) over the reference. However, a significant decrease in albumin (A): globulins (G) ratio (- 87.86%) was observed. Similarly, the exposed fish also showed significant increase in total leucocyte count (+ 121%), differential leucocyte count, respiratory burst (+ 1175%), and nitric oxide synthase (+ 420%). The histological examination of liver and kidney showed tissue injury. Moreover, micronuclei (0.95%), kidney shaped nuclei (1.2%), and lobed nuclei (0.6%) along with DNA damage in the form of mean tail length in the liver (20.7 µm) and kidney (16.5 µm) was observed in the exposed O. niloticus. Potential health risk assessments based on estimated daily intake, target hazard quotient, hazard index, and target cancer risk indicated health risks associated with the consumption of these contaminated fishes. In conclusion, the present study showed that exposure to heavy metals contaminated water can alter immunological response; induce histopathological alterations and DNA damage in the studied fish. The consumption of this contaminated water or fish could have serious impact on human health.

Heavy Metals Assessment in Water, Sediments, Algae and Two Fish Species from River Swat, Pakistan.

The heavy metals were studied in water, sediments, algae, and various tissues of Glyptosternon reticulatum and Cyprinus carpio from River Swat, Pakistan, using flame atomic absorption spectrophotometer. The Zn, Cu, Pb and Ni were higher in water at sewage site compared to upstream and downstream sites. In sediments, the Ni and Cd were not detected whereas Cu, Pb and Zn were higher at downstream followed by sewage and upstream sites. The Ni and Zn in algae were higher at upstream and sewage sites compared to downstream site whereas Pb and Cd were higher at upstream site compared to sewage and downstream sites and Cu was found same at all the three sites. The heavy metals (Zn > Cu > Pb and Ni) in tissues (liver > gills > skin > muscles) of G. reticulatum was higher than in C. carpio. This study recommends the proper monitoring of River Swat in order to save its water and inhabitant aquatic life.

Assessment of Heavy Metals Pollution in Noyyal and Chinnar Rivers, Western Ghats of Tamil Nadu, India with Reference to Crabs (Gecarcinucidae)-A Baseline Study.

In the present study, heavy metals (Cd, Cu, Pb, and Zn) level in the water, sediment, and crabs were analyzed from Noyyal and Chinnar Rivers of the Western Ghats in Tamil Nadu, India. Based on our results, Noyyal River is considered as polluted environment due to the discharge of contaminants by various anthropogenic activities, whereas, Chinnar River maintained as unpolluted one due to its tributary nature of Noyyal River located in Western Ghats hills. The results showed that the heavy metals in water and sediments were higher in Noyyal River. Also, the level of bioaccumulation of studied metals and biochemical constituents were higher in the crab Spiralothelphusa hydrodroma sampled from Noyyal River than Barytelphusa cunicularis collected from Chinnar River. The present findings revealed that the crab sampled from Noyyal River had elevated heavy metals which lead to a significant increase in biochemical constituents to overcome the stress.

Assessment of Cd availability in rice cultivation (Oryza sativa): Effects of amendments and the spatiotemporal chemical changes in the rhizosphere and bulk soil.

Immobilization is widely used to decrease the availability of heavy metals, such as Cd and Pb, in contaminated soils. However, the spatial and temporal changes in the immobilization of soil by amendments combined with planting effects have not been studied well. In this study, unplanted and planted (with rice plants) pot experiments were used to assess the spatial and temporal changes in water-soluble Cd, Fe, Mn, and Ca. Soil properties, such as pH, redox potential (Eh), and dissolved organic carbon (DOC), were continuously recorded in both the rhizosphere and bulk soil using non-invasive rhizon samplers and a microelectrode system (Unisense). In unplanted soil, pH and Eh varied with time, but showed little radial variation from the rhizosphere to the bulk soil. The addition of hydrated lime (Ca(OH)2) sharply increased the pH, DOC, and Ca content; decreased the Eh, Fe content, and Mn content; and gradually decreased the water-soluble Cd content in the soil profile. Hydroxyapatite showed no obvious effects in reducing Cd concentrations in different soil zones. The water-soluble Fe, Mn, Ca, and DOC content did not differ significantly between soil zones over time and a non-significant correlation with water-soluble Cd was shown. In planted soil, the pH increased while the Eh value decreased with an increase in the distance from the roots, regardless of the soil amendments used during the rice growth period. Hydroxyapatite gradually increased but hydrated lime decreased the water-soluble Cd in the rhizosphere. The concentration of water-soluble Cd in the rhizosphere was higher than that of the other soil zones during rice growth. These changes lead to more Cd uptake by roots and induced Cd accumulation in rice tissues. In addition, Cd and Fe concentration in iron plaque showed a significant positive correlation with Cd in rice, indicating that iron plaque promotes the uptake and accumulation of Cd in rice with soil amendments. Compared with the control, hydroxyapatite did not significantly affect the Cd content, while Ca(OH)2 significantly reduced the Cd content in iron plaque and rice tissues. In conclusion, the application of hydrated lime can significantly reduce the risk of Cd accumulation by rice in Cd-contaminated soils under flooding conditions.

[Research progress in phytoremediation of heavy-metal contaminated soils with high-biomass economic plants].

Phytoremediation is one of the important methods for restoring heavy-metal contaminated soils. Using high-biomass economic plants to restore heavy-metal contaminated soils can have both ecological and economic benefits, with great application prospects. Based on the analysis of current situation and existing problems of phytoremediation, we propose the advantages of high-biomass economic plants in contaminated soil remediation, and summarize the recent advances and mechanisms involved in absorbing heavy metals in high-biomass economic plants. Furthermore, the possible methods for improving the remediation efficiency of high-biomass economic plants are also discussed, to provide insights for improving the economic benefits of phytoremediation and promoting its widespread application in the future.

Assessment of long-term effects from cage culture practices on heavy metal accumulation in sediment and fish.

Fish cage farming has been generally banned in some regions since there is growing concern about adverse environmental issue caused by cage culture practices. This paper presents the long-term effects of past cage culture activities on heavy metal accumulation in sediment and fish in one historical cage culture lake (Changshou reservoir, Chongqing, China). Although cages were removed for over one decade in this studied lake, the average concentrations of heavy metals in sediments were still above 2 times higher than their background values, posing a moderate ecological risk. Higher levels of heavy metals appeared in demersal fish who is more susceptible to heavy metals exposure in sediment. Fish consumption would not lead to a significant health risk of most heavy metals. Hg levels in catfish posed a health risk to vulnerable group (children) and specific group (fishermen), whereas the presence of Se decreased Hg toxicity to a safety level. Therefore, it can be speculated that the cage culture activities could influence the heavy metal accumulation in sediment in the long term, however, consumption of current farmed fish in one lake used to carry out cage-culture is safe for local residents.

Impact assessment of legacy wastes from ancient mining activities on current earthworm community.

Mineral resource exploitation by human societies throughout history led to the deposit of mining and smelting wastes and the subsequent contamination of surrounding soils by trace metals. After several centuries, the impact of these legacy hazardous wastes may remain a cause of environmental concern, especially for indigenous soil invertebrate populations such as earthworms. Therefore, we conducted a passive biomonitoring campaign in a former metallurgical district (Vosges Mountains, eastern France). According to community descriptors, we evidenced a significant decrease of anecic and endogeic earthworm density in the former mining stations. To link these results to soil contamination and bioaccumulation levels in earthworm tissues, we propose an original modelling approach using nonlinear mixed-effects regression models. Beyond a dose-response relationship between metal internal concentrations and their levels in soils, we highlighted contrasted behaviors according to ecological groups (epianecics and endogeics most impacted). We interpreted these results in relation to some eco-physiological features without completely exclude the influence of textural characteristics of soil, especially for deep-burrowing species such as anecic strict. Nonetheless, the presence of earthworm populations currently living in highly contaminated sites and handling elevated internal concentrations raises the question of the acquisition of genetic adaptive traits and the trophic transfers of metals.