Archives of Environmental Contamination and Toxicology最新文献

For years, the Caspian Sea has been affected by chemical pollution resulting from human activities. More recently, Viral Nervous Necrosis (VNN) has emerged as a new threat, severely impacting fish populations in this aquatic ecosystem. The aim of this study was to evaluate differences between healthy and VNN-infected mullets along the southwestern coast of the Caspian Sea. A total of 63 individuals were randomly sampled, including 34 Chelon auratus and 29 Chelon saliens. Viral prevalence was higher in C. saliens. Statistical test revealed clear differences between healthy and infected individuals based on their elemental profiles. Infection with NNV was associated with significantly elevated concentrations of several metals, particularly Hg, Pb, Mo, V, and Cu, with Hg showing up to a tenfold increase in infected fish. These findings confirm that the southern Caspian Sea is contaminated with multiple trace elements, which not only compromise ecosystem health but may also predispose fish to viral infections such as VNN.

This study assesses heavy metal accumulation in water, sediment, feeds, and farmed shrimp-tilapia (Penaeus monodon, Macrobrachium rosenbergii, Oreochromis mossambicus) from aquaculture hotspots in Satkhira and Khulna, Bangladesh, to apportion potential metal sources and evaluate associated human health risks. Metal concentrations were quantified using flame atomic absorption spectrometry (AAS) and hydride generation AAS (HG-AAS). The determined average content of As, Cr, Pb, Mn, and Ni in fish species exceeded FAO permissible levels, indicating significant contamination. As, Cr, Pb, and Mn concentrations in water; As, Cr, Pb, Cu, Mn, and Ni content in sediment; and Cr, Pb, Cu levels in fish feeds surpassed FAO and USEPA maximum safe limits. Self-organizing maps (SOM) and positive matrix factorization (PMF) revealed that fish feed inputs were the dominant contributors to Cu (68.1%), Pb (40.1%), Cr (36.1%), Cd (31.6%), As (30%), and Ni (26.1%) accumulation. Principal component analysis (PCA) supported likely shared anthropogenic and natural sources, while cluster analysis (CA) indicated sampling stations’ homogeneity. Target hazard quotient (THQ) values for children indicated potential non-carcinogenic risks from As and Cr exposure, with hazard index (HI) scores for adults (1.22–1.44 > 1) and children (4.77–5.20 > 1), inferring possible cumulative effects in consuming all these fishes. Target risk (TR) assessment suggested a likelihood of carcinogenic risks from As, Cd, Cr, and Pb exposure, with As posing the highest potential risk for both children (TR = 1.36 × 10⁻³) and adults (TR = 3.75 × 10⁻⁴). These findings underscore the necessity of developing strong regulatory structures to ensure sustainable aquaculture by controlling sources of toxic metal contamination.

Graphical Abstract

As a key economic marine aquaculture species in China, sea cucumbers (Apostichopus japonicus) were widely cultured in coastal regions, where were susceptible to crude oil pollution threatening their survival and population recruitment, and the impact of crude oil on non-specific immune functions of sea cucumbers was still limited. Therefore, this study exposed sea cucumbers to water-accommodated fractions (WAFs) of Oman crude oil for 7 d to investigate the effects of crude oil on non-specific immune functions, which were composed of cellular and humoral immune responses. Results showed that WAFs exposure caused oxidative stress and lipid peroxidation, evidenced by elevated reactive oxygen species levels in coelomocytes and initially increased and then reduced malondialdehyde content in coelomic fluid of sea cucumbers. For cellular immune, results showed that WAFs exposure caused dysregulation of phagocytic activity, and a rough reduction in total cell count and an obvious increase in respiratory burst capacity in coelomocytes in a dose-dependent manner, indicating coelomocytes dysfunction and suppression of cellular immune function. Regarding humoral immune function, an obvious decrease in the lysozyme content, total nitric oxide synthase, acid phosphatase and alkaline phosphatase activities, was observed in coelomic fluid with the increase in total petroleum hydrocarbons concentrations, indicating lysosomal dysfunction and suppression of humoral immune function. These findings revealed adverse effects on both cellular and humoral immune responses, suggesting acute immunotoxicity of crude oil in sea cucumbers.

Crude oil and its water-soluble fractions (WSF) are highly toxic to early life stages of fishes, while exposed adults are often considered more resilient. However, research suggests that parental exposure can result in toxic effects in subsequent generations. This study investigated the impact of a crude oil WSF on Atlantic cod (Gadus morhua) broodstock and the subsequent maternal effects on their offspring. Mature Atlantic cod at late gametogenesis were exposed for 20 days to either a crude oil WSF or to control conditions. Over the following month, fish from both groups were repeatedly strip-spawned, and egg batches were fertilized in vitro using pooled sperm from control males. Maternally exposed offspring had accumulated levels of petroleum-derived aromatic hydrocarbons, including monoaromatic and polyaromatic hydrocarbons (PAHs). However, the profile of accumulated compounds was skewed towards lower-molecular weight compounds compared to the exposure water. Crude oil WSF exposure appeared to accelerate spawning readiness in females, resulting in smaller egg diameters in strip-spawned eggs. Additionally, sperm from oil-exposed males showed reduced curvilinear velocity and linearity. Despite these impacts, no significant differences in larval malformations or cardiac activity were observed. Our findings highlight the importance of advancing our understanding of intergenerational impacts of crude oil contamination on key fish species to accurately assess the long-term ecological consequences of petroleum pollution.

Many national and international initiatives aim to control and limit the use of mercury (Hg) in gold extraction. However, the feasibility of Hg eradication from the environment depends on understanding the extent of its distribution. This case study focuses on the spatial and vertical distribution of total mercury (THg) residues at five artisanal mining sites in Tanzania namely, Mgongo, Sekenke, Nyarugusu, Rwamgasa, and Mugusu to assess the feasibility of remediating the problem. The trend showed presence of THg residues in surface layers (0–20 cm), decreasing with depth but still detectable in deeper layers (> 20–100 cm). A horizontal distribution in surface-layer concentrations was also observed along the Mabubi River, which drains across Mugusu mine into Lake Victoria. Among all sites, the highest surface-layer (20 cm) total mercury (THg) concentration was 1.48 ± 0.02 mg/kg, measured from a sample collected at the Nyarugusu mine site, with a moderate decrease to 0.12 ± 0.001 mg/kg at a depth of 100 cm. Other soil samples from the Rwamgasa mine site showed THg concentrations of 0.048 ± 0.012 mg/kg and 0.082 ± 0.01 mg/kg at depths of 70 and 80 cm, respectively. These findings suggest that significant THg residues are detected from surface to deeper layers and wide area of river sediment distribution, mediated by physical, environmental, biological and chemical processes that support simultaneous Hg transport and suspension. The THg residues in soils and sediments challenge the feasibility of remediation efforts in areas with similar wide contamination extents. They demonstrate a long-term legacy of contamination that will continue to impact environmental quality in many regions affected by artisanal mining.

This study presents a comprehensive depth wise assessment of metal contamination in soils surrounding oil and gas drilling sites in the Krishna–Godavari (K-G) basin, encompassing the agriculturally intensive East and West Godavari districts of Andhra Pradesh, India. These regions are characterized by fertile alluvial soils, intensive farming, and dense hydrocarbon exploration, making them particularly vulnerable to environmental degradation. Eighty soil samples were collected from ten drilling locations at multiple depths (00–20 cm, 20–30 cm, 30–60 cm, and 60–90 cm) and analysed using WD-XRF to quantify thirteen elements. Pollution levels were evaluated using multiple geochemical indices, including Geo-accumulation Index (Igeo), Enrichment Factor (EF), Contamination Factor (Cf), Modified Degree of Contamination (mCd), Nemerow Pollution Index (NPI), and Metal Pollution Index (MPI). Surface soils showed strong enrichment of Cu, Zn, Cr, and Pb, with notable migration of metals such as Ba, Ni, and Co into deeper soil horizons. This vertical transport is facilitated by factors including soil permeability, texture, irrigation practices, and seasonal monsoonal rainfall, which enhance leaching and subsurface mobility, particularly in sandy clay and alluvial soils. The results revealed significant vertical and spatial heterogeneity, with extreme contamination by Cu, Zn, and Cr observed particularly at drilling-intensive sites, indicating strong anthropogenic influence. PCA and Pearson correlation delineated both geogenic and anthropogenic associations among the elements. PMF modelling identified six distinct source profiles, including geogenic weathering, drilling muds, corrosion by-products, fertilizer application, petroleum residues, and wastewater reuse. Metals such as Cu, Pb, and Cr showed strong enrichment in surface and subsurface layers, while Ba and Sc exhibited geogenic accumulation at deeper horizons. The interactions between hydrocarbon residues and elements, along with soil physicochemical properties, were found to influence metal mobility and bioavailability. The study underscores the ecological vulnerability of hydrocarbon-rich agricultural zones to drilling-induced contamination and highlights the critical need for scientifically informed waste management, policy enforcement, and remediation planning. These findings provide a depth-resolved geochemical baseline essential for sustainable land-use practices, groundwater protection, and long-term environmental monitoring in petroleum extraction zones.

Birds serve as ecological bioindicators of metal/metalloid contamination due to their continuous environmental exposure. In northeast China, where metal/metalloid pollution is a serious environmental issue driven by anthropogenic activities, its effects on birds remain understudied. This study analyzed tail feathers from ten terrestrial raptor species across four families to assess ecological risks from cadmium (Cd), lead (Pb), arsenic (As), zinc (Zn), copper (Cu), and manganese (Mn). Results showed that Tiger Shrike (Lanius tigrinus) had the highest As (54.35 ± 69.76 mg kg⁻¹) and Cd (5.45 ± 3.94 mg kg⁻¹) residues, followed by Brown Shrike (Lanius cristatus), which also exhibited elevated Pb concentrations (33.61 ± 93.20 mg kg⁻¹). This suggests Shrikes (Laniidae) are more susceptible to metal/metalloid contamination. Significant differences in pollutant levels were found between Little Owl (Athene noctua) and Long-Eared Owl (Asio otus), despite similar feeding behaviors, indicating species-specific sensitivity. Stable carbon isotopic (δ¹³C) values suggested that predatory birds feeding in habitats with lower δ¹³C values may have greater exposure to metal/metalloid pollutants. All studied predatory bird species, except Long-Eared Owl, showed at least one metal/metalloid concentration above toxicity thresholds, highlighting potential ecological risks. These findings emphasize the need for stringent control of anthropogenic metal emissions to mitigate adverse effects on wildlife and human health.

Ingestion of lead (Pb) derived from ammunition used in the hunting of game animals is recognised as a significant potential source of Pb exposure in wild birds globally. While Pb poisoning in wild birds has been studied extensively in North America and Europe, the prevalence of Pb exposure in bird populations elsewhere, particularly in Africa, remains understudied. To address this gap in knowledge, we examined Pb concentrations in the feathers and bones of four waterfowl species (n = 37) from a region in South Africa where recreational hunting regularly occurs. Lead was detected in all feather and bone samples. While most birds had bone Pb concentrations consistent with low-level exposure (< 10 mg kg⁻¹), three individuals displayed concentrations (maximum = 63.5 mg kg⁻¹) associated with lethal Pb poisoning. Lead isotopic ratios in bone samples suggested that Pb shot was the most probable source of Pb in birds with high exposure. These findings align with recent studies on vultures, suggesting that Pb poisoning is more widespread in southern Africa than is currently recognised, affecting not only scavenging species but also waterfowl. The prevalence of elevated bone Pb concentrations compatible with lethal poisoning (8.1%) indicates that Pb exposure could have significant implications for waterfowl populations in the region. Furthermore, substantial indirect risks exist for scavenging and predatory species, as well as for humans consuming meat contaminated with Pb shot. Our findings highlight the importance of addressing the unregulated use of Pb-ammunition across southern Africa, particularly given the large hunting industry the region supports.

Soil contaminated with trivalent chromium (Cr³⁺) induced manganese (Mn) mobilization potentially leading to increased ecological toxicity. Although Cr³⁺ is relatively immobile in soil, its interaction with soil minerals indirectly increases Mn bioavailability, which poses risks to soil organisms. The objective of this study was to assess the bioavailability and potential ecological toxicity of Mn and Cr in Cr³⁺ contaminated soil using chemical extractions, earthworm (Eisenia fetida) toxicity tests, and dehydrogenase activity (DHA) as bioindicators. The mitigation of Mn toxicity in Cr contaminated soil was evaluated following amendments with biochar and calcium carbonate (CaCO₃). Both amendments increased soil pH and reduced bioavailable Mn concentrations by 44–100% through sorption and pH induced immobilization. While bioavailable Cr concentrations also decreased, the effect was less significant because Cr was originally immobile in the soil. Earthworm survival and loss in biomass was not significantly affected by biochar treatment. Dehydrogenase activity was enhanced in biochar and CaCO₃ amended soils, indicating improved microbial activity. Principal component analysis confirmed that biochar and CaCO₃ amendments reduced bioavailability and metal toxicity to levels comparable to uncontaminated soils. The assessment of bioavailability through chemical extraction and toxicity using earthworm and DHA showed similar trends in this experiment. However, high amounts of biochar may negatively affect earthworms, and a holistic approach is required to effectively evaluate amendments for mitigating metal toxicity in soils.