Bulletin of Environmental Contamination and Toxicology最新文献

Accurate quantification of neurotoxic methylmercury (MeHg) in environmental samples is crucial for exploring its formation, behaviors, and risks. Here, we developed and optimized an alkaline digestion-manual purge trap/gas chromatography-cold atomic fluorescence spectrometry (GC-CVAFS) method for the quantification of MeHg in solid matrix samples such as sediments, soils or sedimentary rocks. The alkaline digestion method yielded higher recoveries of MeHg than the acid extraction method. The manual purge trap/GC analysis enhanced the detection of MeHg by increasing the loading volume of the digestion solution, thereby facilitating the detection of lower concentrations of MeHg in the samples when compared to fully automated analysis. The optimized method achieved a method the limit of detection (LOD) of 0.0263 ng·g^-1 and a limit of quantification (LOQ) of 0.0876 ng·g^-1 with relative standard deviations of less than 10%. These results suggest that the alkaline digestion method is appropriate for the pretreatment and quantification of MeHg analysis in sediments or soils, particularly those from non-Hg contaminated sites.

The chronic ecological risks posed by residual PAEs in China remain unclear. In this study, we analyzed the spatial distribution of five typical PAEs in the surface waters of China, dibutyl phthalate (DBP), diethylhexyl phthalate (DEHP), butylbenzyl phthalate (BBP), diethyl phthalate (DEP), and dimethyl phthalate (DMP). The highest concentration of PAEs were detected in the Liao River, ranging from 5 to 79.8 µg/L. DBP was of the PAEs type with the highest concentration in the surface waters in China. By fitting the species sensitivity distribution curves base on the collected data over the past decade, the chronically hazardous concentrations affecting 5% of the aquatic species were calculated to be 0.018, 0.022, 0.062, 0.851, and 9.437 mg/L for DBP, DEHP, BBP, DEP, and DMP, respectively. Thus, DBP, DEHP, and BBP pose the greatest threat to aquatic organisms, and PAEs pose high ecological risks in the Liao, Huangpu, and Pearl Rivers.

Bullfrog tadpoles were exposed (96 h) to water from two sites (the Ibiúna and the Itupararanga reservoir) on the Sorocaba River (São Paulo, Brazil). Metal concentrations (Ba, Cu, Mn, Sr and Zn) and metallothioneins (MTs) levels were determined in the gills (n = 27) and caudal muscle (n = 18). Metals increased in the gills of the animals exposed to the waters of the Sorocaba River in relation to the control and in relation to the animals exposed to the waters of the Ibiúna point. The levels of MT in gills were higher in animals exposed to the Itupararanga reservoir compared to the control. There was a strong correlation between metals and the presence of MT in gills, indicating that this organ can be used in environmental biomonitoring. The results demonstrate the need to protect the waters of the Sorocaba River, and especially the Itupararanga reservoir, through quality monitoring and reduction of anthropogenic pressure.

This study investigates microplastic prevalence in wastewater mixing point from major coastal cities in Tamil Nadu, India, highlighting a significant environmental challenge. In January 2023, 16 wastewater samples revealed microplastics (< 5 mm) ranging from 20 to 51 items per litre. Predominant colours were pink, black, brown, white, green, blue, red, and yellow, with orange being the least common. Microplastic sizes mostly varied from 0.05 to 0.5 mm. Fiber shaped MPs are the predominant, followed by fragments, foam, film and pellets. Predominant polymer types were polyethylene (45%), polystyrene (18%), and polypropylene (15%). These results emphasize wastewater's significant role in introducing microplastics into coastal ecosystems from domestic and industrial sources. Addressing this issue requires effective management plans, including advanced wastewater treatment, public awareness campaigns and regulatory measures. Further research is essential to comprehensively assess ecological impacts and inform sustainable management strategies.

Nowadays, textile industries are one of the major contributors to water pollution, causing a devastating impact on aquatic ecosystems. Therefore, the current study aimed to investigate the impact of a textile azo dye, Eriochrome Black T (EBT), on the liver of a freshwater fish, Clarias batrachus. Fish were exposed to three concentrations of EBT, i.e., 1 mgL^-1, 10 mgL^-1 and 20 mgL^-1, to evaluate oxidative stress markers such as level of lipid peroxidation (LPO) and activity of enzymatic antioxidants (SOD, CAT, GPx and GR), as well as histology and histochemitry following 96 h of exposure. The results revealed a significant increase (p < 0.05) in EBT bioaccumulation, resulting in elevated level of LPO and significant variation (p < 0.05) in the activities of antioxidant enzymes. The percent change calculation of oxidative stress markers of exposed fishes from control one showed that EBT had most significant impact on the fishes exposed to 20 mgL^-1 of EBT. Histological and histochemical examinations also demonstrated the deteriorating impact of EBT on structural architecture of liver. Hence, the present study concludes that EBT causes detrimental impact on fish health by impairing its liver detoxification system and metabolism. Therefore, it is suggested to explore mechanism of EBT toxicity on aquatic organisms so that its hazardous risk can be monitored and preventive measures can be taken.

The pesticide transportation to deeper soil layers can result in groundwater contamination and, consequently, environmental issues. In this research, our objective was to investigate transport efficiency of indoxacaarb using three different soils to understand the leaching potential. The leaching experiments were performed using a 0.01 M calcium chloride solution over five consecutive days. Leachates (water) and soil samples were collected and the residues of indoxacarb were analyzed using gas chromatography mass spectrometry. The method's accuracy was validated by conducting recovery experiments at levels ranging from 0.01 to 0.1 µg/g. The results showed that 82.67 to 84.00%, 80.67 to 82.70% and 76.68 to 78.70% of the indoxacarb applied was retained in the topsoil layer (0-10 cm) for acid, alkali and neutral soil, respectively. Its low leaching behavior, as evidenced by its retention in the topsoil layer and absence in the leachate, contributes to its limited mobility within the soil profile. The study suggests that indoxacarb has no potential for contaminating groundwater and the soil environment through leaching processes.

Field experiments were conducted to investigate the dissipation and persistence residues of trinexapac acid in paddy crop. The treatments consisted of one control and two different concentrations of Trinexapac-ethyl 25% EC (Emulsifiable concentrate) at 30 and 60 g a.i. ha^- 1(recommended and double the recommended dose). Leaf samples were collected at random in each plot separately at 0, 1, 3, 5, 7, 10 and 15 days after foliar application and grain, straw and soil samples were collected at harvest. The mean recovery of trinexapac acid (@ 0.01, 0.05 and 0.1 mg kg^- 1 was more than 75%. At application rate of 30 and 60 g a.i. ha^- 1 (gram of active ingredient per hectare), initial trinexapac acid residues on leaves were 0.29 and 0.44 mg kg^- 1, respectively. Residues were observed even after 15 days of spray. At harvest time, the residues of trinexapac acid in grains were below LOQ (limit of quantification) at 30 g a.i. ha^- 1 treatment whereas, at 60 g a.i.ha^- 1, the residues were found to be 0.02 mg kg^- 1. In straw, trinexapac acid residues were detected to be 0.05 and 0.08 mg kg^- 1 at 30 and 60 g a.i. ha^- 1 treatments, respectively. The soil samples showed 0.04 and 0.08 mg kg^- 1 residue at 30 and 60 g a.i. ha^- 1, respectively. The half life calculated for trinexapac acid came to be 10.10 and 9.09 days revealed the slow dissipation of trinexapac acid in paddy crop. The residue of trinexapac acid reached below LOQ at harvest time. Therefore the recommend dose of trinexapac ethyl is considered safe from consumption point of view.

The effects of B[a]P and Cd on the growth, free-radical metabolism, antioxidants, and photosynthetic fluorescence parameters of Poa pratensis were studied by pot experiments. Results showed that low-concentration Cd (≤ 10 mg·kg^- 1) increased fresh weight, dry weight, malondialdehyde, superoxide anion radical, glutathione, and ascorbic acid. Conversely, high-concentration Cd (≥ 50 mg·kg^- 1) significantly decreased the fresh weight and dry weight, photosynthetic gas exchange, and fluorescence parameters. Water-use efficiency increased by 1.55 times compared with the control at high concentrations of B[a]P (≥ 25 mg·kg^- 1) and Cd (≥ 50 mg·kg^- 1). Principal component analysis showed that Cd played an important role in co-pollution. P. pratensis mitigated B[a]P and Cd co-contamination toxicity by regulating antioxidant activity and water-use efficiency. P. pratensis can tolerate 1, 5, and 25 mg·kg^- 1 B[a]P, as well as 1 and 10 mg·kg^- 1 Cd. P. pratensis was also highly capable of degrading B[a]P and extracting Cd in soils co-contaminated with B[a]P and Cd.

Although microplastic (MP) pollution in aquatic ecosystems has been a critical issue, a significant portion of previous studies has been limited to marine environments. Few studies have evaluated MP abundance in inland waters, and those that exist often ignore seasonal variations. This study aimed to assess the seasonal variations in microplastic (MP) abundance in the İskenderun Technical University (İSTE) Pond. MP abundance ranged from 0.5 MPs/L to 10.8 MPs/L, with a mean of 3.7 MPs/L. Fiber-shaped, black-colored, small-sized (< 1000 μm) MPs were commonly found on the surface water. Statistical analysis confirmed significant variations in MP abundance across seasons. The abundance of MPs in the surface water correlated with the mean annual precipitation. Atmospheric deposition and storm water runoff were major contributors to microplastic pollution in the pond. PP and PET particles were identified. The findings of this study contains preliminary results that can be used in the development of future legislations and regulations.

This study evaluated the effects of water-soluble fractions (WSF) of stranded oil sampled from the beaches of Trancoso and Massarandupió (Bahia, Brazil) following a mysterious oil spill along Brazil's northeast coast (2019-2020). The samples were characterized for aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) and tested for chronic toxicity in the embryo-larval stages of the sea urchin Echinometra lucunter. The WSFs contained high levels of PAHs, some of which were above the acceptable levels for water in Brazil, and toxicity to sea urchin embryos tended to occur at higher concentrations.