Bulletin of Environmental Contamination and Toxicology最新文献

This study investigated the effects of different concentrations of zinc (Zn) and selenium (Se) on antioxidant enzyme activity and mercury (Hg) transport/accumulation in rice seedlings under Hg stress through hydroponic experiments. The results demonstrated that combined Zn-Se application significantly enhanced physiological performance and Hg sequestration compared to individual treatments, with low-to-medium concentrations (10-40 mg/L Zn + 0.0005-0.002 mmol/L Se) exhibiting optimal efficacy. The synergistic treatment (40 mg/L Zn + 0.002 mmol/L Se) improved chlorophyll content, upregulated SOD, CAT, and GSH activities (GSH increased by 51.7%), and minimized Hg translocation and accumulation (reduced by 34.95% and 35.06%, respectively). These findings highlight the potential of Zn-Se co-application as a strategy to mitigate Hg toxicity in rice.

Microplastics (MPs) are emerging contaminants of global concern due to their potential to disrupt physiological and biochemical functions in aquatic organisms. This study investigated the effects of polyethylene (PE) microplastics on Labeo rohita, a commercially important freshwater carp. Fingerlings (25 ± 2 g) were exposed to 0 (control), 1, 3, and 5 mg/L PE microplastics for 60 days, followed by a 30-day recovery period in clean water. Microplastic accumulation was quantified in gill, liver, and intestine, and impacts on tissue biochemistry (carbohydrates, proteins, lipids), antioxidant enzyme activities (SOD, CAT, GST), micronucleus formation, and behavioural responses were assessed. Results revealed dose-dependent reductions in carbohydrate, protein, and lipid levels, significant decreases in antioxidant enzyme activities, and a marked increase in micronuclei frequency at higher concentrations, indicating oxidative stress and genotoxicity. During recovery, proteins and carbohydrates largely returned to baseline, whereas lipid content, antioxidant enzymes, and micronucleus frequencies showed partial restoration, especially at higher exposure levels. These findings demonstrate that PE microplastics induce metabolic disruption, oxidative stress, and genomic instability in L. rohita, with recovery being incomplete at elevated concentrations, highlighting potential ecological and aquaculture risks.

Male infertility has become an important concern, with environmental factors playing a significant role. Most studies have focused on single or similar types of environmental endocrine-disrupting chemicals (EDCs) in male infertility, despite human exposure to their complex mixtures. However, the contribution of each chemical remains unclear, and the role of nutrients in mitigating reproductive health effects from chemical exposure is not well understood. This study analyzed NHANES 2013-2016 data (n = 1,455) to examine relationships between exposure to 24 chemicals, 21 nutrients, and sex steroid hormones. Linear regression showed negative associations between phthalate metabolites and total testosterone (TT). Mixture analyses using weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) confirmed this, identifying propylparaben, mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and triclosan as key chemicals. Sufficient zinc, calcium, vitamin C, and vitamin E intake alleviated reproductive hormone dysfunction. Participants in the lowest quartile of zinc intake exhibited the most significant changes in TT and estradiol (E₂) compared to those in the highest quartile. These findings suggest nutrient intake may be associated with attenuation of effects of EDC exposure on sex hormones.

Microplastics (MPs) and cadmium (Cd) are both common contaminants in agro-systems, but research on the synthetic effects remains limited. This study focuses on the eco-physiological responses and assess whether co-contamination of microplastics affects the bioavailability of Cd. Our results found that the co-existing MPs with Cd resulted in a significant increase in malondialdehyde (MDA) compared to the exposure to single MPs. Under the single MPs treatment, MDA content in plants increased first and then decreased with the increase of MPs content. This trend is also manifested in the co-existing polyethylene (PE) with Cd. However, polyvinyl chloride (PVC) co-existing with Cd caused decreases of the content of MDA. The exposure to single polyethylene (PE), polyvinyl chloride (PVC), and co-existing MPs with Cd significantly increased the electrical conductivity of Chinese cabbage, and they showed a fluctuating upward trend, with the increase of the content of added MPs. Both MPs single exposure and co-contaminated with Cd stimulated the antioxidant system, caused in a higher superoxide dismutase and peroxidase activities at lower content of MPs (p < 0.05). The addition of MPs was able to alleviate the stress effects of Cd. Under the same content of Cd and MPs, PE treatment absorbed less Cd than PVC. Under co-existing of PE, the absorption of Cd in stems and roots of Chinese cabbage decreased by 16.20% and 9.12% on average, while with co-presence of PVC, it decreased by 14.21% and 4.98% on average. TF and BCF also showed a similar trend. These results unraveled that the relieving effect of PE on Cd stress was better than that of PVC and it has a better retention capacity for heavy metals. PE and PVC can reduce the Cd transport from the root system to the stem and leaf parts. The findings of this study provide reference to further understanding of the effects of MPs and Cd synergies on the plant-soil system, and also offer a physiological and ecological basis for the construction of synergistic governance strategies for new pollutants in agricultural ecosystems.

Understanding the environmental fate of herbicides is essential for ensuring safe and sustainable crop production systems. This study evaluates the degradation behavior of herbicides in the soil and mustard crop in a rice-mustard cropping system by assessing the combined effects of tillage practises and residue retention. A field experiment was conducted using a split-plot design under conventional tillage without residue (CT-R) and zero tillage with residue retention (ZT + R), involving pre-emergence applications of pendimethalin at 339 and 500 g/ha and pyroxasulfone at 76.5 and 102 g/ha. The herbicides were extracted using ultrasound-assisted extraction and method showed good linearity, minimal matrix effect, high sensitivity and good recoveries confirming its suitability for quantifying herbicides in soil and mustard samples. The half-lives (DT₅₀) of pyroxasulfone ranged from 11.38 to 13.19 and 6.78 to 10.07 days under CT-R and ZT + R, respectively across both years. Pendimethalin exhibited biphasic degradation with initial-phase DT₅₀ ranging from 3.61 to 5.15 and 3.66 to 3.92 days, while final-phase DT₅₀ ranging from 20.21 to 28.51 and 14.34 to 23.73 days in CT-R and ZT + R, respectively. The residues of herbicides in soil (< 0.01 µg/g) and mustard (< 0.05 µg/g) at harvest were below the limit of detection, indicating their safe degradation by crop maturity. The study demonstrates that conservation tillage practices can enhance herbicide degradation dynamics, contributing to safer environmental outcomes and supporting the sustainable intensification of mustard-based cropping systems.

We quantified the acute toxicity of water-soluble fractions (WSFs) from crude oil, gasoline, diesel, lubricant oil, and two insulating mineral oils (IMOa, IMOb) to the Neotropical fish Astyanax altiparanae. Six independent static-renewal assays (110 fish each; 11 nominal WSF dilutions [0-100% v/v]) were performed. The calculated LC₅₀-96 h and LC₁₀-96 h were gasoline = 2.65 and 0.5%; diesel = 16.22 and 2.75%; IMOa = 17.01 and 5.35%; petroleum = 23.59 and 1.76%; lubricant = 27.65 and 11.24%; and IMOb = 53.58 and 7.84%. Gasoline was the most toxic, reflecting its high BTEX and low-molecular-weight PAH content, whereas lubricant oil and IMOb were least toxic, consistent with their dominance of high-molecular-weight hydrocarbons. The unexpectedly high toxicity of IMOa, comparable to diesel, is likely attributable to proprietary antioxidant additives. These baseline LC₅₀/LC₁₀ data fill a gap for tropical freshwater species and provide reference points for subsequent sub-chronic testing and regional environmental-risk assessments. By establishing a clear toxicity hierarchy for common hydrocarbon contaminants and highlighting the overlooked role of additives, this work is crucial for developing scientific-grounded water quality guidelines tailored to protect the unique and often understudied biodiversity of neotropical freshwater ecosystems.

In the present work, we aimed to extract and identify microplastics (MPs) in two different species of fish, namely, Rohu fish (Labeo rohita) and Freshwater Shark (Wallago attu), inhabiting the Tanguar Haor (wetland) that is a part of the Surma River, Bangladesh. Three different parts, namely, the stomach, intestine, and dorsal muscle of the corresponding fish samples, were digested with a 10% KOH solution. We conducted a qualitative assessment using FTIR, UV-visible, and SEM/EDS measurements to confirm the presence of MPs. The study identified various types of MPs, including Polypropylene (PP), Polyethylene (PE), Polyvinylchloride (PVC), Polyamide (PA), Polyethylene terephthalate (PET), and Polymethyl methacrylate (PMMA), in three different parts of the respective fish samples. Among the different portions of fish, the intestine contained the most diverse range of MPs, with six different types identified. In comparison, five types of MPs were found in the stomach, and only three types were observed in the dorsal muscle. The mean diameter of the identified MPs determined by SEM analysis revealed the smallest mean diameter of 570 nm in the dorsal muscle portion of the L. rohita and the largest mean diameter of 889 nm in the intestine part of W. attu, respectively. Thus, the outcome of this investigation sheds light on the possible presence of MPs in freshwater wetland ecosystems.

Diatoms, a type of photosynthetic microalgae, play a crucial role in carbon fixation, accounting for approximately 40% of global carbon sequestration. They respond rapidly to environmental perturbations, making them critical indicators of dynamic marine ecosystems that are often impacted by crude oil contamination. This study aims to assess the resilience of diatom species under crude oil stress. We modelled six-member diatom consortia enriched from oil-contaminated regions of the Cambay basin, Gujarat, India. We exposed them to crude oil (500, 750, 1000 ppm), as well as nitrate (N) and phosphate (P) stress, over 30 days. Results indicated a decline in cell numbers and chlorophyll levels, accompanied by the rapid formation of lipid droplets (LDs). Chaetoceros gracilis, Surirella librile and Halamphora coffeaeformis showed robust resilience, surviving at 750 ppm, while no species thrived at 1000 ppm. Notably, LD formation emerged in S. librile, C. gracilis, H. coffeaeformis, and Navicula rostellata. Identifying them as tolerant and sensitive sentinel species could help earmark them as bioindicators for crude oil pollution and select species for ecological restoration in contaminated marine environments.

Fish is a primary protein source in Côte d'Ivoire, accounting for 39% of animal protein intake. However, the current local production from fisheries is insufficient to meet the annual national demand. Fish farming could address this gap, but the production of high-quality fry remains a key challenge. Water quality plays a crucial role in fry production, yet many tilapia farms in the country are susceptible to agrochemical contamination from nearby agricultural activities, which can affect both fish health and reproduction. This study aims to assess genotoxicity of a hatchery water in tilapia using the alkaline comet assay. Water samples from Modern Hatchery of Gonaté in the Haut-Sassandra Region of Côte d'Ivoire were collected in November 2021 and October 2022 for pesticides analysis. Simultaneously, fish broodstock samples were collected for genotoxicity assessment. Our results show that in 2021, when pesticides were used in the surrounding area, DNA damage in the erythrocytes of tilapia broodstock (41.6 ± 6.7% tail DNA) was significantly higher (ANOVA, F(3,31) = 222.9, P < 0.001) compared to individuals sampled in 2022 (15.5 ± 4.4%) after pesticide use in the adjacent food crops ceased. Pesticide residues, including glyphosate, acetamiprid, and mancozeb, were detected in water samples from 2021 but were absent in 2022, coinciding with the cessation of pesticide use near the hatchery. These findings underscore the impact of agrochemical exposure on DNA damage in tilapia, which may have detrimental effects on fry production.

The global response to the SARS-CoV-2 pandemic involved intensified disinfection of public spaces, predominantly using 70% ethanol (EtOH) and bleach (sodium hypochlorite). However, the extensive application of these agents has raised concerns regarding their ecotoxicological impact on aquatic ecosystems, particularly following their entry into drainage systems where they can form hazardous disinfection by-products. This study assessed the acute toxicity of commercial 70% EtOH and bleach on two key freshwater species: the cladoceran Ceriodaphnia dubia and the gastropod Biomphalaria glabrata. The 24-h median effective concentration (EC50) of 70% EtOH for C. dubia was 0.45% v/v (3.91 g/L), while the 24-h median lethal concentration (LC50) for B. glabrata was 3.8% v/v (33 g/L). For bleach, the corresponding toxicity values were significantly lower, at 0.0000024% (0.025 mg/L) for C. dubia and 0.0776% (815 mg/L) for B. glabrata. These results demonstrate that both disinfectants induce acute toxicity at concentrations substantially below their typical use levels. Notably, bleach proved to be more toxic than 70% EtOH by five orders of magnitude for C. dubia and two for B. glabrata. This study underscores the critical need for cautious use and continuous environmental monitoring of these disinfectants to mitigate their ecological impact and highlights the importance of developing sustainable alternatives.