Archives of Environmental Contamination and Toxicology最新文献

The St. Johns River (SJR) is an ecologically and economically important estuarine river system undergoing extensive anthropogenic change. In this study, water quality parameters (dissolved oxygen, temperature, salinity, pH, hardness, alkalinity, ammonia–N, nitrate–N, and nitrite–N) and a suite of metals (cadmium, copper, lead, nickel, silver, and zinc) were measured in water samples collected from eight sites in the lower SJR from 2019 to 2022. This project was continued from previous work that documented these parameters in the river from 2017 to 2019. Aquatic communities such as phytoplankton can be indicative of river health; therefore, phytoplankton were also collected from each site, and the diatom component was identified. The total number of taxa in each sample ranged from 60 to 190, with 25 taxa accounting for the majority (64%). Similar to water quality, seasonal fluctuations in phytoplankton abundance and diversity were observed, with an increased relative abundance of Skeletonema costatum and Skeletonema subsalsum in times of lowered diversity. Furthermore, decreased phytoplankton diversity correlated with increased metal concentrations in the lower SJR. Multivariate analyses highlighted significant interactions among phytoplankton diversity and water quality variables. Significant parameters affecting phytoplankton biodiversity included salinity, pH, temperature, copper hazard quotient, and the nickel hazard quotient. This study provides new information about the impact of human disturbance on biotic communities and the complexity in predicting population changes.

The escalating concentrations of emerging contaminants in water systems and the possible environmental threats they emphasize the necessity for more sophisticated methods in the evaluation of water quality. Traditional bioassays raise ethical concerns, require intricate procedures, entail significant expenses, and only allow for endpoint measurements. The using of nitrifying bacteria in bioassays has resulted in increased sensitivity to a wide range of toxic substances, making them valuable for the identification of water pollution. This study introduces a novel nitrifying bacteria bioassay kit for detecting heavy metal contaminants in water. This bioassay is specifically designed for expedited analysis of oxygen consumption. This technique enables the identification of a range of toxic metals. Optimization studies indicated that 100 mg ammonia NH₄⁺–N/L, and 1 mL acclimated culture were the ideal conditions facilitating the necessary volume of gas consumption for sensitive data generation. Determined EC₅₀ values of the selected toxic metals were: chromium (Cr⁶⁺), 0.51 mg/L; silver (Ag⁺), 2.90 mg/L; copper (Cu²⁺), 2.90 mg/L; nickel (Ni²⁺), 3.60 mg/L; arsenic (As³⁺), 4.10 mg/L; cadmium (Cd²⁺), 5.56 mg/L; mercury (Hg²⁺), 8.06 mg/L; and lead (Pb²⁺), 19.3 mg/L. Metagenomics analysis found key species in the research included Nitrosomonas eutropha, Nitrosomonas oligotropha, Nitrosomonas europaea, Nitrobacter vulgaris, Nitrobacter winogradskyi, Nitrospira moscoviensis and Nitrospira lenta. In addition, this bioassay is ideal for field screening and real-time monitoring due to its simplicity and reliability. This bioassay provides a precise, economical, and effective substitute for more intricate and ethically problematic techniques, enhancing the effectiveness of water quality monitoring programs.

Neonicotinoids are insecticides that are used globally and can persist in soil and surface water, posing a threat to ecosystems. In this study, we exposed the invasive freshwater amphipod Dikerogammarus villosus to environmentally relevant and relatively high concentrations of thiacloprid, a widely used agricultural neonicotinoid active ingredient and its commercial form Calypso® for two days. The acute effects were investigated at the behavioral (immobility time) and biochemical [glutathione S-transferase (GST) and acetylcholine esterase (AChE) activity] levels. Calypso® concentrations of 10 µg/l and 100 µg/l a significantly increased the immobility time, while thiacloprid exerted such an effect only at 100 µg/l. The GST enzyme activity did not change in the thiacloprid-treated groups; however, the 10 µg/l and 100 µg/l Calypso® concentrations significantly increased the GST activity. All Calypso® concentrations significantly decreased AChE activity until the highest Calypso® concentration was reached, and an interesting outcome was the ‘U-shaped dynamics’ of AChE activity. In contrast, thiacloprid had no significant blocking effect on AChE activity at any of the concentrations tested. Neonicotinoid insecticides are neurotoxins that selectively target nicotinic acetylcholine receptors in the insect central nervous system. However, their widespread use has a growing impact on nontarget animals. This study confirms the risk of neonicotinoids to aquatic invertebrates by providing evidence that neonicotinoids can also affect both behavioral and biochemical processes in D. villosus.

Long-term fire retardants are employed to combat and control wildfires by altering the way fuels burn, and they continue to decrease fire intensity after water in the retardant solution has evaporated. After application, fire retardants may persist on dry stream beds or in riparian habitats before precipitation events flush the retardant into intermittent streams. We exposed juvenile (30–60 days post swim-up) rainbow trout (Oncorhynchus mykiss) to fire retardants weathered for 7–56 days on different substrates (duff, gravel, high organic content soil, and low organic content soil) under static conditions for 96 h to evaluate the potential toxicity of two current-use long-term fire-retardant (LC95A-R and MVP-Fx) products. Trout mortality was greater in LC95A-R treatments compared to MVP-Fx due to higher concentrations of LC95A-R in the applied product than MVP-Fx at the same application rate. Underlying substrate affected fire-retardant toxicity, with 31% higher average mortality for products applied to duff and gravel compared to soil. Differences in mortality across substrates and products after weathering may be attributed to differences in the mix ratio of applied product and interactions of product chemistries with underlying substrate. These interactions resulted in elevated ionic concentrations of the overlying water in duff and gravel treatments. Trout mortality decreased 15% for products weathered 56 days compared to 7 days. Our results suggest that long-term fire retardants may persist in the environment and that underlying substrate may alter the toxicity of these products upon entrance into an intermittent stream.

The aquatic environment has been contaminated by pyrethroids and triazole pesticide applications, which pose serious health risks to the aquatic ecosystem and human beings. Therefore, the current study aims to evaluate water quality parameters, fungal diversity, and distribution of snails and aquatic plants of certain Egyptian water courses contaminated with pyrethroids and triazole pesticides. Seasonal samples were taken throughout 2021 from different water courses at Giza Governorate and Tanta (Gharbeya Governorate). Qualitative and quantitative surveys showed significant differences in water physical parameters between the two investigated governorates. Deltamethrin, permethrin, Es-fenvalerate, and lambada-cyhalothrin showed the highest pyrethroids concentrations, while tebuconazole, tetraconazole, and difenoconazole were the highest triazole concentrations. Fungal diversity displayed 21 molecularly identified fungal species related to four fungal genera: Aspergillus, Fusarium, Penicillium, and Trichoderma. Penicillium sp. and Aspergillus niger were the most frequent species. Snail diversity recorded 10 and 9 species in Giza and Tanta, respectively. Physa acuta was the most abundant snail. Ten species of aquatic plants were observed in Giza, while six species were observed in Tanta. Specifically, Eichhornia crassipes and Lemna gibba were the dominant species in the two governorates, with the relative abundance (39 and 22%) in Giza and (27 and 23%) in Tanta, respectively. Water quality parameters and seasonal variations could control fungal diversity, snails, and aquatic plant distribution. Different relations between pesticides and biological communities may reflect the ability/inability of certain snails and fungi species to commensalism with pesticide concentrations. Continuous pesticide monitoring is essential for life below water and aligns with SDG14.

This study investigates the contamination status and dispersion of 11 potentially toxic elements by exploring the potential mechanistic pathways by analyzing 60 samples (coal, ash, topsoil, and subsoil) from and around the coal-based brick kilns by neutron activation analysis. The mean_n=10 concentrations (μg g⁻¹) of scandium (Sc: 3.85), zinc (Zn: 79.21), Antimony (Sb: 4.06), and cesium (Cs: 4.81) in coal samples and manganese (Mn: 488), antimony (Sb: 10.9), and cesium (Cs: 20.3) in ash samples were 2.8–4.3 times and 1.1–2.5 times higher than world average values, respectively. In soil samples, average_n=40 abundances (μg g⁻¹) of chromium (Cr: 109), zinc (Zn: 144), arsenic (As: 8.98), rubidium (Rb: 113), antimony (Sb: 2.29), and cesium (Cs: 14.3) are 1.1–5.7 times higher than the crustal values. Additionally, geo-environmental indices showed that cesium (Cs) and chromium (Cr) had undergone severe modification relative to the crustal value, and the corresponding soil samples were moderately contaminated. The positive matrix factorization (PMF) model reveals that aerodynamic transportation contributes 22% to the elemental transportation of manganese, titanium, and iron throughout the soil profile in distant soil. In comparison, hydrodynamic transportation contributes 25% for As, Zn, and Sc in both topsoil and subsoil in the nearby soil. However, the combined process of bio-geo-accumulation, hydrodynamic leaching, and aerodynamic convection mechanisms contributes 53% of the dispersion and distribution of cesium (Cs), cobalt (Co), rubidium (Rb), and chromium (Cr) in the ambient pedosphere around the brick kilns which local geology, soil properties, solubility, and weathering can further influence. Our research findings contribute to advancing scientific approaches for investigating soil contamination, including the mechanistic pathways of potentially toxic elements and the risks associated with brick kilns.

The widespread use of incense in indoor environments, particularly in cultural and religious practices, poses significant health risks due to particulate matter (PM) emissions. This study examines the chemical composition, particle morphology, and deposition dynamics of PM from four types of incense: Cup dhoop, Cone dhoop, Natural Incense Powder, and Agarbatti. Advanced analytical techniques, including SEM, FTIR, ICP-MS, and CAM, were employed to characterize particles, focusing on their size, elemental makeup, and surface properties. Particle sizes ranged from 12.02 µm to 422.3 nm, with lenses showing higher concentrations than filters. Elements such as sodium (300 µg/m³) and mercury (1.99 µg/m³) were prominent in lenses, while arsenic (6.2 µg/m³) and cadmium (0.19 µg/m³) were dominant in filters. Neurotoxins like aluminum, lead, and mercury highlighted potential risks, including oxidative stress and systemic toxicity. Deposition modeling revealed age-related differences, with children (8 years) experiencing higher pulmonary deposition (16.8% for Cup dhoop), while adults (21 years) showed greater head region deposition (37.6% for Agarbatti). Hydrophobic particles in filters (contact angle 119.2°) contrasted with hydrophilic particles in lenses (69.8°), increasing ocular exposure risks. Cone dhoop exhibited the highest cancer risk, affecting 5 in 100,000 individuals, emphasizing its hazardous nature. FTIR identified microplastics like polypropylene and polyvinyl chloride, known to adsorb and transport heavy metals, compounding health risks. These findings highlight the critical health impacts of incense emissions, particularly for children, and underscore the urgent need for stricter regulations, improved ventilation, and public awareness to mitigate exposure.

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Freshwater salinization is increasing globally through seawater intrusion, road de-icing, and changes in anthropogenic land uses. Concurrently, freshwaters are browning with the rise in dissolved organic carbon (DOC) concentrations, while water pH is falling. Elevations in external major ion concentrations (Na⁺ or Ca²⁺) and low pH, independently disturb osmoregulatory homeostasis in freshwater organisms. Several studies have demonstrated that DOC often mitigates osmoregulatory stress responses to acidic pH. However, the interactive effects of these three water quality parameters together have been relatively understudied. Transepithelial potential (TEP), the electrical gradient across the gills between the animal and the external water, can be used as an index of osmoregulatory stress. We investigated whether DOC and exposure to elevated major ions interact with TEP responses at circumneutral and low environmental pH in the freshwater rainbow trout. Two natural DOCs, one allochthonous and the other autochthonous, were used. To aid interpretation, three model compounds of known chemical structure were also employed (tannic acid, sodium dodecyl sulfate, bovine serum albumin), based on the criteria that they structurally resemble or functionally behave like certain chemical moieties of humic or fulvic acids, major components of DOC. The Multi-Ion Toxicity Model predicts that a disturbance in absolute TEP is indicative of salt toxicity; however, recent studies have shown that ΔTEP (the change in TEP relative to the baseline) may be more predictive. Our data followed a pattern that could be described by the Michaelis–Menten equation. Therefore, considering Michaelis–Menten constants (Km and ΔTEP_max), absolute TEP and ΔTEP, we used a weight of evidence approach to predict how DOC and pH will influence Na⁺ or Ca²⁺ toxicity. We conclude that key chemical moieties of DOC will likely play pH-dependent roles in both Na⁺ and Ca²⁺ toxicity.

Graphical Abstract

Aquatic organisms can uptake metals directly from contaminated water or by consuming contaminated prey. Knowing the relative importance of these routes is critical to understand how metals enter and move through aquatic food webs. We previously established that nymphs of the aquatic dragonfly Erythemis simplicicollis accumulate elevated copper (Cu) concentrations when living in contaminated wetlands, but the route of uptake was not identified. In this study, we evaluate copper accumulation with a model two-trophic-level laboratory food chain comprised of E. simplicicollis dragonfly nymphs as predators and Aedes aegypti mosquito larvae as prey to gain better insight into Cu accumulation dynamics in these aquatic insect predators. Treatments consisted of dragonfly nymphs exposed to copper through diet (A. aegypti larvae prey exposed to 100 µg/L Cu-contaminated water), water (100 µg/L Cu), diet + water, and a control. Each treatment included 15 replicates, and 10 pretreatment nymphs were analyzed. Exposures lasted 32 days or until nymph death. Copper accumulation in nymphs and nymph mortality was compared among treatments. Eating contaminated prey did not elevate copper concentrations in E. simplicicollis. In contrast, highest copper concentrations accumulated in E. simplicicollis when exposed to contaminated water, in both the water-only and in the diet + water treatments. Additionally, mortality was greater when exposed to copper-contaminated water. Even though the nymphs did not trophically accumulate Cu, direct uptake of Cu from water provides a point of Cu entry into a food chain.

Artisanal and small-scale gold mining (ASGM) is the largest anthropogenic source of mercury globally. Few studies have explored how this toxicant affects avian wildlife in Indonesia, an ASGM hotspot. Here, we use feather samples from museum specimens (n = 92) of Indonesian birds to examine changes through time in methylmercury (MeHg), diet, and foraging habitat (inferred from stable isotope ratios of nitrogen, δ¹⁵N, and carbon, δ¹³C, respectively). We ask how MeHg changes between time period (1860–1980 vs. 1980–2019) given increases in mercury emissions due to ASGM and describe how foraging guild and among-species variation in diet influence Indonesian bird feather MeHg concentrations. Time period was not a significant factor, with specimens associated with increased ASGM activity (collected post-1980) not significantly higher in MeHg concentrations compared to specimens collected pre-1980. Feather MeHg concentrations varied significantly among species, foraging guilds, and by habitat use. Carnivore and insectivore MeHg concentrations were above thresholds associated with sublethal effects. This is the first report of MeHg in Indonesian passerines, kingfishers, and woodpeckers. It provides critical information on mercury exposure in a region with high avian diversity that is severely impacted by mercury pollution.