Bulletin of Environmental Contamination and Toxicology最新文献

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.

Global plastic use has surged, generating 20-90 million tons of waste annually, which breaks down into microplastics that contaminate environments. While marine microplastic pollution has been widely studied, research on agroecosystems, particularly paddy soil, remains limited. This study assessed microplastic pollution across four types of agricultural land use in the Cachar district: boro rice cultivation, rainfed rice cultivation, upland rice cultivation, and natural forests. Boro rice soil exhibited the highest contamination (213 particles per 100 g of soil), while natural forests had the lowest (98 particles per 100 g of soil). Two primary types of microplastics were found; fibers (89.86%) and fragments (10.14%). Most microplastics were smaller than 500 μm (67.79%), while only 7.83% were larger than 1 mm. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analyses revealed smoother microplastics in forests and coarser ones in agricultural soils. EDX detected elements such as carbon, oxygen, aluminium, silicon, copper, sulphur, bromine, and molybdenum. This study offers vital baseline data for managing plastic waste and mitigating environmental and health risks.

Anodic oxidation using boron-doped diamond (BDD) anode offers a promising treatment method for the deep treatment of dyeing wastewater. However, limited attention has been on the phytotoxicity evolution and their cause of degraded wastewater. Here, two representative coordination-structured dyeing wastewaters were first degraded using a BDD anode, and the resulting degradation intermediates were analyzed. Subsequently, lettuce seed root length, shoot length, and germination rate were evaluated to assess wastewater's phytotoxicity at different degradation periods. Finally, acute toxicity and the relative concentration changes of intermediates were further analyzed to identify the causes of toxicity. Results indicated that the treated wastewater was more toxic than pre-oxidation due to the generation of multiple toxic intermediates, significantly inhibiting seed growth. The synergistic effects of toxic substances and Na₂SO₄ electrolytes contributed to increased toxicity. This study demonstrated that the decolorization process of dyeing wastewater through anodic oxidation was toxic and provided a basis for evaluating the agricultural reuse potential of oxidized wastewater.

Microplastic (MP) contamination is a growing environmental challenge, affecting marine biodiversity and fisheries on a global scale. This study quantified the abundance, physical characteristics, and polymer types of MPs in the gastrointestinal tracts of two key fish species, Chinese silver pomfret (Pampus chinensis) and white pomfret (Pampus argenteus), collected from the offshore fishing grounds of Bangladesh during March 2024. A total of 25 adult specimens per species were analyzed via oxidative digestion, density separation, and filtration. The polymers of the isolated MPs were identified using Fourier Transform Infrared Spectroscopy (FTIR). MPs were detected in 100% of specimens, with mean abundances of 20.0 items/fish in P. chinensis and 6.6 items/fish in P. argenteus. Fiber-shaped (59-64%) and transparent (53-65%) MPs, predominantly < 500 µm, were most common. Polyamide (PA) and polyethylene terephthalate (PET) were the main polymers. Ecological risk assessment using the Polymer Hazard Index (PHI) indicated the presence of high-risk polymers, but the Pollution Load Index (PLI) suggested overall minor MP contamination relative to the reference baseline. These findings highlight the widespread occurrence of MPs and the predominance of fishing-related polymers in offshore pomfrets of the Bay of Bengal. Notwithstanding the limitations of our sample size and spatial scope, these initial results provide first evidence on the need for regionally coordinated monitoring, improved plastic waste management, and further research on biological effects and food web transfer in tropical marine systems.

Excessive use of petroleum products has led to increased anthracene contamination in ecosystems, highlighting the need for effective monitoring and remediation strategies. This study evaluated the phytoremediation potential of three ornamental plant species-Epipremnum aureum, Tagetes erecta, and Portulaca grandiflora-for anthracene-contaminated soil. After 60 days of exposure to anthracene at concentrations of 25, 50, and 100 mg kg^-1, various parameters including growth, chlorophyll content, malondialdehyde (MDA) levels, and oxidative stress-related enzyme activity-were evaluated. Results revealed that in the presence of anthracene, E. aureum showed no visible stress symptoms, while P. grandiflora exhibited mild stress. In contrast, anthracene treated T. erecta experienced significant reductions in biomass (18.10-62.07%), moisture content (4.65-8.31%), shoot length (20.19-40.07%) and increased root length (14.18-62.92%) compared to the control. The total chlorophyll content in E. aureum and P. grandiflora increased at concentration of 100 mg kg^-1, whereas T. erecta exhibited hormesis in chlorophyll content. Presence of anthracene significantly increased MDA concentrations and altered the oxidative stress related parameters in all three plants. Epipremnum aureum demonstrated the highest anthracene removal efficiency (52.82 ± 2.23%), followed by P. grandiflora (31.64 ± 2.68%) and T. erecta (21.11 ± 2.65%). This study highlights the potential of E. aureum and P. grandiflora as effective candidates for restoring anthracene-contaminated soils, offering valuable insights for environmental remediation efforts.