Heavy metal(loid)s (HM) pollution in aquatic environments is a serious issue due to the toxicity, persistence, bioaccumulation, and biomagnification of these pollutants. The main sources of HM contamination are industrial activities, mining, agricultural practices, and combustion of fossil fuels. Fish can accumulate HMs through a process called bioaccumulation. As larger predatory fish consume smaller fish, these HMs enter the main food chains and can become increasingly concentrated in their tissues and finally reach humans. Here, we provided a general and concise conclusion from current research findings on the toxicological effects on different body systems. Exposure to HMs can lead to a range of adverse health effects, including neurological damage, developmental disorders, kidney damage, cardiovascular problems, and cancers. Their long-term accumulation can result in chronic toxicity even at low levels of exposure. HMs exert cellular cytotoxicity by disrupting essential cellular processes and structures. They can interfere with enzyme function, disrupt cell membrane integrity, induce oxidative stress, and cause DNA damage, ultimately leading to cell death or dysfunction. Prevention and control of HMs involve implementing measures to reduce their release into the environment through regulations on industrial processes, waste management, and pollution control technologies. Additionally, monitoring and remediation efforts are crucial for identifying contaminated sites and implementing strategies such as soil and water remediation to reduce human exposure and mitigate the impact on ecosystems. To conclude, HM accumulation in fish poses serious risks to public health and the environment, necessitating urgent interdisciplinary efforts to mitigate their harmful effects and promote sustainable practices that reduce HM flow into biological systems.

Ny-& Aring;lesund, located in Arctic Svalbard, is one of the most sensitive areas on Earth to global warming. In recent years, accelerated glacier ablation has become remarkable in Ny-& Aring;lesund. Glacial meltwaters discharge a substantial quantity of materials to the ocean, affecting downstream ecosystems and adjacent oceans. In August 2015, various water samples were taken near Ny-& Aring;lesund, including ice marginal meltwater, proglacial meltwater, supraglacial meltwater, englacial meltwater, and groundwater. Trace metals (Al, Cr, Mn, Fe, Co, Cu, Zn, Cd, and Pb), major ions, alkalinity, pH, dissolved oxygen, water temperature and electric conductivity were also measured. Major ions were mainly controlled by chemical weathering intensity and reaction types, while trace metals were influenced by both chemical weathering and physicochemical control upon their mobility. Indeed, we found that Br & oslash;ggerbreen was dominated by carbonate weathering via carbonation of carbonate, while Austre Lov & eacute;nbreen and Pedersenbreen were dominated by sulfide oxidation coupled with carbonate dissolution with a doubled silicate weathering. The higher enrichment of trace metals in supraglacial meltwater compared to ice marginal and proglacial meltwater suggested anthropogenic pollution from atmospheric deposition. In ice marginal and proglacial meltwater, principal component analysis indicated that trace metals like Cr, Al, Co, Mn and Cd were correlated to chemical weathering. This implies that under accelerated glacier retreat, glacier-derived chemical components are subjected to future changes in weathering types and intensity.

Long-term wastewater irrigation leads to the loss of calcium carbonate (CaCO3) in the tillage layer of calcareous land, which irreversibly damages the soil's ability to retain cadmium (Cd). In this study, we selected calcareous agricultural soil irrigated with wastewater for over 50 years to examine the recalcification effects of sugar beet factory lime (SBFL) at doses of 0%, 2.5%, 5%, and 10%. We found that SBFL promoted Cd transformation in the soil from active exchangeable species to more stable carbonate-bonded and residual species, which the X-ray diffraction patterns also confirmed results that CdSO4 reduced while CdS and CaCdCO3 increased. Correspondingly, the soil bioavailable Cd concentration was significantly reduced by 65.6-84.7%. The Cd concentrations in maize roots and shoots were significantly reduced by 11.7-50.6% and 13.0-70.0%, respectively, thereby promoting maize growth. Nevertheless, SBFL also increased the proportion of plant-unavailable phosphorus (P) in Ca8-P and Ca10-P by 4.3-13.0% and 10.7-25.9%, respectively, reducing the plant-available P (Olsen P) content by 5.2-22.1%. Consequently, soil P-acquiring associated enzyme (alkaline phosphatase) activity and microbial (Proteobacteria, Bacteroidota, and Actinobacteria) community abundance significantly increased. Our findings showed that adding SBFL to wastewater-irrigated calcareous soil stabilized Cd, but exacerbated P limitation. Therefore, it is necessary to alleviate P limitations in the practice of recalcifying degraded calcareous land.

Coastal wetland soils are frequently underlain by sulfidic materials. Sea level fluctuations can lead to oxidation of sulfidic materials in acid sulfate soils (ASS) and increased acidity which mobilises trace metals when water levels are low, and inundation of coastal wetland soils and reformation of sulfidic materials when water levels are high. We measured the effect of surface water level fluctuations in soils from coastal wetland sites under four different vegetation types: Apium gravedens (AG), Leptospermum lanigerum (LL), Phragmites australis (PA) and Paspalum distichum (PD) on an estuarine floodplain in southern Australia. We assessed effects of fluctuating water levels on reduced inorganic sulfur (RIS) in terms of acid volatile sulfide (AVS), chromium reducible sulfur (CRS) and trace metals (Fe, Al, Mn, Zn, Ni). Intact soil cores were incubated under dry, flooded and wet-dry cycle treatments of 14 days for a total of 56 days. The flooded treatment increased RIS concentrations in most depths in the AG, PA and PD sites. Lower CRS concentrations occurred in all sites in the dry treatment due to oxidation of sulfidic materials when the surface layer was exposed to lower water levels. CRS was positively correlated with SOC in all treatments. The highest net acidity occurred in the dry treatment and lowest occurred in the flooded treatment in most sites. Inundation with seawater caused SO42- reduction and decreased soluble Fe in the PA and PD sites. General decreases in Al, Zn and Ni concentrations in flooded treatments may have been due to adsorption onto colloids or co-precipitation with slight increases in pH. SO42- concentrations decreased in the LL, PA and PD sites in the flooded treatment due to reformation of pyrite. In general, accumulation of RIS in soils under different vegetation types following brackish water inundation varied according to vegetation type, which may be linked to differences in organic material input and particle size distribution. Geochemical characteristics reflected whether oxidation or reduction processes dominated at each site in the wet-dry cycle treatments, with oxidation dominating in the LL and PA sites and reduction dominating in the AG and PD sites. This is likely due to more readily decomposable organic matter forming sulfidic materials during short periods of inundation.

Glaciochemical records serve as one of the best archives and as good proxies to indicate regional and global anthropogenic influences. The Himalayas, with fragile ecosystems and pristine environments, hold the third largest reservoir of glacier ice and represent an ideal region to investigate trace metal pollution using glacier records. Limited studies on glacially recorded trace metals in the Himalayas usually collect samples from individual glaciers and report a few trace metals in different seasons. We provide a comprehensive and in-depth understanding of the glacially recorded trace metals in the central Himalayas regarding their spatial distribution, seasonal variability, and anthropogenic signals. We analyzed six representative metals (Cu, Zn, Cd, Cr, Pb, Co) and found that the trace metal concentration range largely varied between the studied metals and sampling sites. The Zn metal concentration is higher, attributed to the contribution of natural sources (e.g., forest fires, dust storms) and anthropogenic sources, including industrial and traffic-related emissions. The Pb concentration showed striking seasonality due to the relatively natural input of local material during the monsoon season and the regional and long-range transport of anthropogenic sources during the non-monsoon season. There was a clear spatial variation in certain trace metals, such as Cu, Zn, and Pb, showing decreasing trends with increasing elevation. The enrichment factor (EF) results showed that Zn metal was highly enriched, followed by Cu and Cd, indicating that Zn metal was relatively highly susceptible to intensified human activities. The seasonal paradox between the enrichment factor and metal concentration revealed that the EF of the monsoon season was usually higher than that of the non-monsoon season, and vice versa regarding metal concentrations primarily associated with metal deposition in regional climate regimes, particularly atmospheric circulation. We suggest that the analytical method can influence the trace metal concentration and EF calculation, resulting in a previously unrecognized bias in the seasonality of trace metals. Future research should prioritize stable isotopes of trace elements (e.g., Pb, Cu) in glaciers that would provide valuable information in identifying the potential source of anthropogenic inputs and the degree of extent affecting the glaciochemistry of the Himalayas.