Bulletin of Environmental Contamination and Toxicology最新文献

Groundwater arsenic contamination in the middle Indo-Gangetic plains poses an emerging threat to livestock health. We determine the arsenic concentration in water and its bioaccumulation levels in feed and cattle reared in areas with arsenic groundwater contamination. Based on a preliminary survey and observations, ten cattle each from Akbapur village in the Naubatpur block as the control and from Kasimchak village in the Danapur block as the test group, were selected. All selections adhered to established inclusion criteria. Samples of feed, water, and other biological materials were collected from each group. The mean arsenic (mg/L) in water (0.0785 ± 0.004) and feed (1.046 ± 0.076) from test village were above the permissible levels and significantly higher than the control village. The arsenic concentrations in blood, milk, hair, urine, and dung were also significantly higher in test group compared to the control cattle. This study indicates that exposed cattle bio-accumulates arsenic.

The tire rubber antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and its transformation product, 6PPD-quinone (6PPDQ), have garnered much research attention since the latter was identified as the causative agent of urban runoff mortality syndrome in Coho Salmon (Oncorhynchus kisutch) in the Pacific Northwest of the United States. Fewer than 10 species, all within the fish family Salmonidae, have been shown to be sensitive to 6PPDQ, while several fish and invertebrates are sensitive only to the parent compound. We evaluated the toxicity of 6PPD and 6PPDQ at nominal concentrations of up to 2400 and 94 µg/L, respectively, to juveniles of the freshwater mussel Lampsilis siliquoidea. This species was added to the list of those not sensitive to 6PPDQ at concentrations below solubility limits, but water spiked with 6PPD caused mortality, potentially attributed to a hydrolysis product. Additional work would help to further evaluate potential hazards of transformation products of this ubiquitous chemical.

This research investigated the transfer of potentially toxic metals through the agricultural food chain, from water and soil to maize, and subsequently to cow milk, at roadside (RS) and control site (CS) locations. Using atomic absorption spectrophotometry (AAS), the concentrations of Zn, Cu, Co, Mn, Mo, Fe, Pb and Cd were determined in samples of irrigation water, soil, maize and milk. Significant concentrations of Cd and Pb were detected in RS samples compared to CS samples, indicating anthropogenic inputs primarily from vehicle emissions. Milk metal concentrations at RS for Zn, Cu, Co, Mn, Mo, Fe, Pb, and Cd were 0.239, 0.001, 0.0011, 0.035, 0.001, 0.04, 0.0016, and 0.002 mg/L, respectively, while the corresponding CS concentrations were 0.288, 0.0005, 0.0008, 0.115, 0.001, 0.02, 0.0003, and 0.001 mg/L, respectively. The Contamination Factor (CF) and Bioconcentration Factor (BCF) indicated extensive transfer of trace metals in soils to maize. The health risk associated with the daily metal intakes, as assessed by the health risk dimensions (HRI), identified Cu and Cd as the most significant risks. The findings underscore the vulnerability of roadside agricultural systems to potentially toxic metal accumulation and emphasise the importance of continuous monitoring to safeguard food safety and public health.

Due to the increasing concentration of the mixture of nanoparticles in the aquatic system, the interaction of nanoparticles with algae-bacteria consortia has increased immensely, leading to toxicity. The present study investigated the effect of long-term exposure (35 days) of CuO and ZnO nanoparticles (NPs) on the growth of consortia of Scenedesmus obliquus and Escherichia coli in BG-11 medium. The effects of NP concentrations (0, 0.1 mg/L, 1 mg/L, 10 mg/L, and 100 mg/L) on consortia at a ratio of algae to bacteria (100:1) were studied. At an environmentally- relevant NP concentration of 0.1 mg/L, the order of reduction in chlorophyll a (or chlorophyll b or biomass) was found to be: CuO alone > ZnO NPs > mixture of NPs. Overall, the exposure of algae-bacteria consortia to the 0.1 mg/L mixture of NPs resulted in a lesser effect on the growth and biomass production than that due to exposure to one type of NPs. After 35 days, the increase in lipid content for the combination of nanoparticles was estimated to be 0.74 ± 1.38%, 1.28 ± 1.33%, 2.68 ± 1.73%, and 4.51 ± 2.11%, respectively. At the environmentally-relevant 0.1 mg/L concentration, the order of toxicity, based on the reduction in growth parameters (e.g., chlorophyll), was consistently observed as: CuO NPs > ZnO NPs > Mixture of NPs. The primary hypothesis of mechanisms, as supported by the data, is that the NPs heteroaggregate which in turn reduces the overall bioavailability of the toxic components to the microbial consortia over the long-term exposure period.

This study investigated heavy metal pollution in water bodies of metal mining areas in the Han River Basin (Shaanxi section), a critical water source for China's South-to-North Water Diversion Project. Water samples were collected from mining-affected areas, transition zones, and the main stem. Pollution levels, ecological risks, and health risks were assessed using the Nemerow Comprehensive Pollution Index, Potential Ecological Risk Index, and Health Risk Assessment models. The most severe pollution was found in mining-affected waters, where average Fe and Mn concentrations exceeded China's Class III standard by 4.8 and 3.5 times, respectively, and the maximum Cd concentration exceeded the standard by 2.9 times. The Nemerow index indicated moderate to severe pollution in mining areas (P_N up to 4.21), transitioning to no pollution in the mainstream (P_N < 0.7). Cd and Tl were identified as the primary ecological risk factors, with potential ecological risk indices (E_i) reaching 128.32 and 44.0, respectively. The health risks associated with drinking water ingestion were significantly higher than those from dermal contact, with Cd-induced carcinogenic risks for children as high as 5.12 × 10^-5 a^-1, far exceeding the acceptable level (1 × 10^-6 a^-1). Children were particularly vulnerable to elevated risks. Correlation and PCA analyses indicated that Cd, Pb, Fe, Mn, Be, and Ni originated mainly from mining activities, while Sb and Tl were influenced by both geological background and industrial sources. This study provides a foundation for targeted pollution control in high-risk areas.

The toxicity of microplastics (MPs) can vary depending on the route of exposure, yet the effects of dietary exposure remain poorly understood. In this study, we evaluated the effects of chronic dietary exposure to MPs on the marine amphipod Parhyale hawaiensis (Dana, 1853) over 35 days. Amphipods were exposed to 53-63 µm polyethylene microspheres (18 ± 4 MPs per food unit) through their diet. We assessed survival, reproduction, molting frequency, condition factor, oxygen consumption, MP accumulation, and fecal elimination. P. hawaiensis readily ingested and excreted MPs via feces. Exposure to MPs significantly increased oxygen consumption in exposed individuals (0.21 ± 0.053 mg O₂/g/h) compared to controls (0.12 ± 0.07 mg O₂/g/h), suggesting elevated metabolic costs potentially associated with MP processing and elimination. Despite this physiological stress, no significant effects on reproduction or growth were observed. These results indicate that, although ingested MPs can be eliminated through feces, their presence may still impose sublethal metabolic stress on marine detritivores.