Bulletin of Environmental Contamination and Toxicology最新文献

There have been reports confirming the presence of microplastic pollution in rice fields, which have potential negative effects on rice cultivation. In this article, the growth characteristics and oxidative stress levels of rice seeds were analyzed in the presence of polystyrene microplastics with different particle sizes (50 μm, 50 nm) and concentrations (0-1500 mg/L), as well as their co-exposure to 2,4-epibrassinolide. The micro-particles had no significant effect on the growth of rice seeds, however, the nano-plastic had an inhibitory effect on the growth of rice seed and the effect was the strongest at high concentration. The addition of brassinolide alleviated the inhibitory effect of the nano-plastics on rice seed. The oxidative stress level results indicated that the addition of brassinolide weakened the oxidation induction effects of microplastics, improved the antioxidant capacity of rice seeds under microplastics stress.

This study investigated the distribution, sources, and ecological toxicity of polycyclic aromatic hydrocarbons (PAHs) in surface sediments along the Mekong River, from its entry into Vietnam to its outflow into the East Sea. The results showed that total PAH concentrations ranged from 53.66 to 1205.35 ng/g dry weight, with an average of 281.08 ± 391.13 ng/g dry weight. Among the 16 PAH compounds analysed, Pyrene (Pyr) and Fluoranthene (Flu) were detected in all sediment samples. Naphthalene (Nap) had the highest concentration among the detected PAHs. Diagnostic ratio and principal component analyses indicated that PAHs originated from mixed sources, including traffic emissions, coal and biomass combustion, petroleum leakage, and wastewater discharge. Based on the risk quotient (RQ), PAHs posed low to moderate ecological risks. Both adults and children in the study area may be exposed to cancer risks due to the presence of carcinogenic PAHs in sediment samples.

The usage of biodegradable plastics as a substitute for traditional plastics is increasing yearly. However, the toxicity of biodegradable microplastics to freshwater microalgae is still unclear compared to traditional microplastics; In addition, the toxic release effects of different aging methods on biodegradable plastics are also unknown. Taking polyethylene (PE) and polylactic acid (PLA) as the research objects, the acute toxicity (96 h) of Microcystis aeruginosa under high temperature aging (HT) and ultraviolet aging (UV) conditions was investigated. Results showed that more cracks appeared on the surface of aged PLA, and the inhibition effect on microalgae was greater than that of aged PE. Moreover, the inhibition rate of microplastics on microalgae after UV aging (PLA: 39.64%, PE: 32.66%) was higher than that of HT aging (PLA: 30.95%, PE: 26.36%). In addition, the reactive oxygen species (ROS) levels in the treatment groups subjected to UV aging (PLA: 7-45%, PE: 3-28%) increased more than those subjected to HT aging (PLA: 6-31%, PE: 2-20%). This study revealed the toxicity difference between PLA and PE on Microcystis aeruginosa under different aging conditions, which provided a theoretical basis for studying the effects of aging biodegradable plastics on freshwater microalgae.

This study assesses the histological abnormalities induced by graphene nanosheets in Cirrhinus mrigala fish (Mrigal) treated orally with plant extracts of Tamarix aphylla and Albizia lebbeck. In 1st phase of experiment LC₅₀ of graphene nanosheets was determined as 81.22 mg/kg over 96 h. In 2nd phase of experiment fish were exposed to 15th, 10th, and 5th fraction of the LC50 for 28 days exhibited liver and intestinal abnormalities, including vacuolation, necrosis, villous atrophy, and crypt hyperplasia. In 3rd phase of experiment co-treatment with Tamarix aphylla and Albizia lebbeck (5, 10, and 15 mg/kg) for 56 days reversed these changes. Graphene nanosheets increased oxidative stress parameters (glutathione, malondialdehyde, catalase, and lipid peroxidase), but the effect is considerably reversed by treatment with plant extracts. Raman and TEM analyses confirmed graphene nanosheet characterization, while GCMS and HPLC analysis of plant extracts revealed antioxidant properties. The study concludes that graphene nanosheets induce oxidative stress and histological damage in Cirrhinus mrigala (Mrigal), mitigated effectively by Tamarix aphylla and Albizia lebbeck extracts.

This study assessed the herbicides atrazine (ATZ) and glyphosate (GLP) concentration in water and sediment of Argentine Pampas shallow lakes with agriculture activity (AA) mainly transgenic crops of soybeans and corn on the coast near the water (Cochicó and Guaminí), and in a lake with extensive cattle activity (CA) close to their coasts (La Salada de Monasterio). Also, the concentration of ATZ in the muscle and the frequency of testicular histopathological lesions (THL) of pejerrey fish (Odontesthes bonariensis) were studied. In the water, maximum concentrations of ATZ (0.279 µg l^- 1) and GLP (0.015 µg l^- 1 were found in Guaminí and Cochicó shallow lakes. For sediments, the maximum concentrations were 32.6, 45.2, and 14.9 µg kg^- 1 for ATZ, GLP, and its metabolite aminomethylphosphonic acid (AMPA), respectively in the same shallow lakes. The results showed that 30.6% of the pejerrey sampled had THL being fish from Guaminí (60%) the most affected. Of the pejerrey analyzed for ATZ, 80.82% of them had this herbicide in the muscle. The highest percentage of THL was found again in pejerrey from Guaminí (68.75). with sterility as dominant (59.38%). These findings suggest a possible adverse effect on the gonads related to the herbicides identified in the water, sediments and in muscle which is an alarm signal in using agrochemicals and protecting the fish biota.

Microplastics, which decompose from large pieces of plastic and cause water pollution, are becoming an increasing environmental problem due to their stable structure, high mobility, and ease of interaction with organic compounds in the environment. Large amounts of microplastics enter surface waters through wastewater and stormwater. Therefore, it is necessary to develop simple and accessible methodologies as a foundation for establishing reliable and effective strategies for microplastic removal from aquatic environmental samples. In this study, the removal of microplastics (< 1 mm) at laboratory scale using synthetic microplastics is investigated by three methods: filtration, centrifugation and flocculation. For this purpose, polypropylene-based microplastic particles are prepared and turbidity is used to measure removal. In this study, all three methods are investigated to determine a more effective method for the removal of microplastic particles. Among the three methods studied, the centrifuge method showed higher removal efficiency than the filtration and flocculation methods for the removal of microplastic particles from aqueous solution. The removal efficiency of microplastic particles by the centrifugation method reached 95.6% and was 90.6% by the filtration method. The flocculation method has a lower removal efficiency of microplastic particles than the centrifugation and filtration methods, ranging from 75.6 to 81.8%. In general, the results show that centrifugation is the more suitable and efficient method to remove microplastic particles from aqueous solution.

In aquatic arthropods, molting is essential for normal development. An earlier study showed that 3-phosphoglycerate (3PG) and phosphoenolpyruvate (PEP), which are present in the exoskeleton, play important roles in its calcification. Under normal culture conditions, we found higher levels of 3PG and PEP at the pre-molt stage than that at the post-molt stage in the carapace of kuruma prawn juveniles (Penaeus japonicus). In subsequent experiments, exposure of environmentally relevant concentrations of fipronil (0.1, 0.05, and 0.025 µg L^-1) for 24-96 h resulted in significant decreases in 3PG and PEP in the exposure group. Furthermore, we found higher internal insecticide concentrations in molted prawns than those in unmolted prawns. Given that molting requires a higher amount of energy, these changes are indicative of the allocation of more and less energy for detoxification and molting, respectively, which may contribute to the mitigation of fipronil bioconcentration.

With the development of nanotechnology, nano-hydroxyapatite (nHAP) is gradually used for the immobilization and remediation of heavy metals in soil. However, there are few studies on the immobilization of Pb in alkaline agriculture soil amend with nHAP. This study applied 0.5% and 1% nHAP as remediation materials to two Pb contaminated alkaline soils (A and B) from the surrounding of substation in northern China. Comprehensive evaluations of Pb mobility were conducted using the Tessier sequence extraction method, DTPA extraction, and in vitro gastrointestinal simulation (SBRC and PBET methods). The Tessier sequence extraction results revealed that following nHAP addition, there was a shift of Pb towards the residual fraction, with decreases in exchangeable, carbonate, and Fe/Mn oxide fraction. The risk assessment code (RAC) decreased from 27.7 to 36.0% to 21.9-35.1%, and the mobility factor (MF) dropped from 78.8 to 85.9% to 65.6-75.0%. DTPA extraction indicated contrasting effects: the bioavailable Pb extracted by DTPA assay in soil A increased from 36.6% to 43.0-58.3%, while the bioavailable Pb in soil B decreased from 68.3% to 48.4-52.7%. Similar to DTPA results, the Pb bioaccessibility of soil A increased from 63.9% to 41.9% to 70.0-72.6% and 47.6-63.8% in SBRC and PBET gastric phase after 0.5% and 1.0% nHAP treatments 90 days. However, the Pb bioaccessibility of soil B decreased from 76.6% to 56.5% to 54.9-56.5%, 35.0-35.6% by SBRC and PBET, respectively. The study highlights the potential of nHAP in alkaline soil, but the immobilization efficiency varied with soil characteristics.

The main goal of this study is to evaluate the potential risk of high levels of particulate matter with diameter ≤ 2.5 μm (PM_2.5) on children´s health, using PM_2.5 monitoring in the western zone of the city of Rio de Janeiro and health data determined in the same area. Results showed that, during this period, in more than 50% of days PM_2.5 concentration were > 15 µg m^- 3. This value is the maximum concentration to ensure a good air quality according to the WHO guidelines and the Brazilian legislation. Furthermore, in 2023, 28.24% and 5.29% of mortality rates, for children between 1 and 5 years old, were due to respiratory and cardiovascular diseases respectively. On the basis of the particulate matter levels recorded in this study and the WHO AIRQ + software, we estimate that PM_2.5 levels may have contributed to approximately 8.5% of the total number of these deaths and could have been prevented.

The sediment equilibrium phosphorus concentration (EPC₀) is used to estimate phosphorus (P) flux at the sediment-water interface. This parameter is most commonly measured by the batch method which potentially disrupts natural sediment structure at sampling. This manuscript describes the use of a dynamic mesocosm system consisting of sediment cores modified to recirculate overlying waters from the cores through an external reservoir that is subject to experimental manipulation. The method allows EPC₀ to be determined on intact cores while preserving in-situ sediment structure. Calibration of the system demonstrated time to steady state after P-spiking to vary by spike concentration and temperature. Comparisons between EPC₀ from batch and mesocosms revealed higher EPC₀ in cores compared to batch methods. When sediment structure was disrupted by homogenization, technique differences were reduced.