Bulletin of Environmental Contamination and Toxicology最新文献

Accumulation of plastic waste is an alarming environmental concern across globe. For which, microbial degradation offers an efficient ecofriendly solution. Thus, the present study focuses on the exploration of new bacterium that can grow on and utilize polyethylene. Ochrobactrum intermedium SA1 isolated from sewage sludge (Jaipur, India) was characterized and evaluated for growth on both thermally pre-treated and untreated low-density polyethylene (LDPE) and high-density polyethylene (HDPE) films in synthetic medium at 35 °C and pH 6.5 for 30 days. The bacterium was grown successfully on the polyethylene films such that 3.458 ± 0.373% and 1.586 ± 0.142% gravimetric weight loss was observed for LDPE and HDPE films, respectively. Further, LDPE and HDPE films showed highest decrease in tensile strength of 126.67% and 75.62%, respectively which was corelated with atomic force microscopy analysis depicting the increase in surface roughness after incubation with the bacterial isolate. Therefore, we believe that more detailed studies will establish Ochrobactrum intermedium SA1 as a potential tool in clearing the global burden of plastics.

Sediment cores were collected from the nearshore to bay mouth region in Daya Bay, aiming to describe the historical patterns of heavy metals deposition in the sediment. During the last 40 years, the heavy metals exhibited significant different deposition behaviors in the sediment, in which As, Zn, Cr were more enriched and contributed to metals pollution in this area. Moreover, heavy metals deposition exhibited completely opposite behaviors from the nearshore to bay mouth region. An increasing of pollution level and ecological risk was observed in the nearshore, whereas a decreasing trend was detected in the bay mouth. Principal component analysis suggested that heavy metals were possibly derived from anthropogenic activities in the nearshore, whereas natural sources were the main sources in bay mouth. The results indicated the urgency of implementing efficient measures to mitigate heavy metals contamination in the adjacent sea.

This study focuses on the composition and sources of dissolved organic matter (DOM) in the Fancun Reservoir, located in Ningguo City, Anhui Province, China. The investigation was conducted by analyzing the spectral characteristics of DOM using UV-Vis absorption spectra and fluorescence spectroscopy. The humic substances were dominated by fulvic acid, with an average DOM concentration of 30.54 mg/L at the reservoir outlet primarily originating from internal release. Fluorescence indices suggested a strong autochthonous contribution of DOM and weak humus characteristics. Three DOM components were identified through parallel factor analysis. Aromatic protein substances in DOM ranged from 0.52 to 4.49%, suggesting minimal anthropogenic influence. The average fluorescence lifetime increased from 0.81 ns at the reservoir entrance to 0.91 ns at the outlet, with an average relative quantum yield of 4.99%, implying stabilization throughout the reservoir. Correlation analysis indicated positive correlations (P < 0.001) between absorption coefficients at specific wavelengths. Principal component analysis explained 67.7% of the total variance, indicating highly common DOM sources across sites.

The co-occurrence of pesticides in aquatic ecosystems highlights the need for studies investigating their potential toxicity as mixtures to the aquatic biota. Well-designed studies are essential to assess the presence and toxicity of relevant pesticide mixtures, particularly those such as the chloroacetamide herbicide metolachlor (MET), the triazole fungicide epoxiconazole (EP) and the diamide anthranilic insecticide chlorantraniliprole (CAP), which have not been previously tested, and whose co-occurrence is possible in waters close to cultivated areas. A solid phase extraction ultra-performance liquid chromatography-tandem quadrupole mass spectrometry method was developed to quantify equivalent toxicity concentrations for CAP, EP, and MET in artificial freshwater during acute toxicity tests. Compounds were separated within 1.30 min, showing linearity over the calibration ranges of 2-150 µgL^-1 for CAP and 50-3000 µgL^-1 for EP and MET. Detection and quantification limits were (µgL^-1): 0.001 and 0.0037 MET; 0.000038 and 0.00013 EP; and 0.002 and 0.007 CAP, respectively. Precision and accuracy met intra-assay validation requirements. Recoveries were tested at low and high concentration levels and were between 77% and 120%. Additionally, matrix effect showed different behavior among compounds. In an acute toxicity test proposed, MET and EP remained stable (24 h), while CAP decayed 27% ± 4% in the same period. The method proved effective despite different concentrations in toxicity testing design.

Microalgae are often used in different industrial sectors and can be used as indicators of aquatic environmental health. An essential step for cultivating microalgae is assessing the cell density, which is traditionally performed through cell counting by optical microscopy (OM). However, this method has limitations, mainly in terms of runtime and low reproducibility. Assessing the optical density (OD) by spectrophotometry was investigated as an affordable alternative. The OD of the green microalgae Desmodesmus subspicatus and Tetraselmis sp. was detected at 680 nm. The correlation between the cell density and OD was suitable for both microalgae and the accuracy was comparable to traditional OM counting. In toxicological tests, the OD technique allowed the monitoring of microalgal growth in the presence of the chemicals K₂Cr₂O₇, KCl and sodium dodecyl sulfate. This study sheds some light on this well-known technique, which is an important contribution since few articles have explored its potentialities and fragilities.

Atrazine is a predominant herbicide globally, and its residues are commonly found in natural water bodies due to its extensive use. Atrazine is known for its detrimental effects on the reproductive abilities of aquatic plants and animals. Our study explored the impact of maternal exposure to atrazine on the survival and performance of offspring using the water flea Daphnia magna as a model organism. We investigated how the life-history traits and population dynamics of maternal D. magna and their offspring are influenced by atrazine. We hypothesized that exposure to atrazine in mothers would negatively affect the survival and performance of their offspring. The findings revealed that short-term exposure to atrazine adversely affects fitness-related traits, manifesting as decreased survivorship and reduced fecundity. Offspring from atrazine-exposed mothers displayed a limited recovery in fitness; no mortality was observed during the 14-day experiment, yet fecundity remained significantly reduced. At the population level, maternal exposure to atrazine led to a decreased population carrying capacity. The notable maternal effects on offspring reproduction underscore the long-term toxicity of atrazine to D. magna populations, suggesting prolonged consequences even after the cessation of atrazine pollution. This study underscores the transgenerational effects of atrazine, highlighting its persistent threat to D. magna populations.

Fast-paced global industrialization due to population growth poses negative water implications, such as pollution by heavy metals. Phytoremediation is deemed as an efficient and environmentally friendly alternative which utilizes different types of hyperaccumulator plants known as macrophytes for the removal of heavy metal pollutants from contaminated water. In this study, the removal of Cu(II), Ni(II), Pb(II), and Cd(II) heavy metal ions contaminated water was studied by using an aquatic plant, Persicaria amphibia (L.) collected from Ladik Lake, Samsun, Turkiye. The experiments were carried out hydroponically in the laboratory conditions. Synthetic heavy metals contaminated water (5, 10, 25, 50, 100 mg kg^- 1), and domestic and industrial water were used in the experiments. The domestic and industrial water samples were taken from Aksu and Batlama streams in Giresun province. All physical plant changes were noted, and pH, conductivity, and dissolved oxygen levels of the hydroponic system were measured regularly during the experiments. In order to determine the effects of heavy metals on the plant, the chlorophyll (a, b and total) and carotenoid contents as well as the biomass of the plant, were measured. According to the phytoremediation experiments the amounts of accumulated heavy metals in plants were found as Cd(II) > Ni(II) > Cu(II) > Pb(II) in single systems and as Cd(II) > Ni(II) > Pb(II) > Cu(II) in competitive systems. The maximum amounts of heavy metals accumulated in plants were determined as 171 ± 9 mg kg-1 for Cd(II), 143 ± 7 mg kg-1 for Ni(II), 134 ± 8 mg kg-1 for Cu(II) and 55 ± 4 mg kg-1 for Pb(II). In addition, bioconcentration factor (BCF) values ​​were calculated to make comparisons with the phytoextraction potential of the plant. This study emphasizes the importance of P. amphibia with high bioaccumulation potential for phytoremediation and suggests that it could be employed to restore water in heavy metal-contaminated areas.

This study aims to investigate the ability of cadmium (Cd) accumulation in Peristrophe bivalvis cultivated in a pot experiment for 60 days at various Cd amounts of 0, 20, 60, and 100 mg/kg. Throughout the experiment, no toxic effects were observed, and the presence of Cd did not inhibit the growth of the plants. A linear correlation coefficient (P < 0.05) showed that there was a significant decrease in leaf stomata opening due to Cd stress. After treatment with a high concentration of Cd in the root rather than the shoot (P < 0.05), the plant's Cd accumulation increased significantly. P. bivalvis demonstrated reduced translocation factor (TF) and bioconcentration factor (BAF) values < 1; nevertheless, by the end of the experiment, the enhanced Cd uptake value on concentration showed the maximum value of 1.56 mg/plant. The results suggest that P. bivalvis had a tolerance and phytostabilization ability for Cd.

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.