Archives of Environmental Contamination and Toxicology最新文献

Urban freshwater streams across northern latitudes are undergoing increasing salinization due, in part, to road salt inputs during winter months. Road salt contamination has been monitored across Canada for over 40 years; however, the scale of contamination in the Pacific Northwest, which experiences relatively mild and rainy winters, is not well understood. A network of almost 40 water quality loggers in the Lower Mainland of Vancouver, B.C., Canada (VLM) was leveraged to better understand the scale of road salt inputs to local streams and identify factors that influence the magnitude and occurrence of these contamination events. Specific conductance data from these loggers indicate that road salt is entering creeks, resulting in brief salt pulses that typically last 1 day or less. Road salt pulses occur as frequently as three times per week in winter months and can attain maximum chloride concentrations above British Columbia’s acute guideline for chloride (600 mg/L Cl⁻) by as much as 11-fold in streams. The amount of road salt entering creeks is influenced by the extent of impervious surface in the surrounding catchment basin, with more urbanized creeks receiving higher inputs. Interestingly, cumulative salt inputs do not correlate with winter severity and remain consistent even during mild winters. Acute pulses of road salt occur in VLM streams between November and March, coinciding with the spawning and incubation period of locally important Pacific salmon species such as coho and chum salmon. This timing poses a direct risk to developing salmonids, and the benthic invertebrates which sustain them later in development.

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Lead (Pb) poisoning poses a significant threat to wildlife. A primary cause of Pb poisoning is the unintentional ingestion of Pb ammunition and fishing weights, which are still used for hunting and fishing in numerous regions globally. While the effects of Pb poisoning on birds and mammals are well established, impacts on reptiles are less well documented and difficult to assess under field conditions. In this study, we investigated the effects of extreme Pb exposure on captive sub-adult Nile crocodiles (Crocodylus niloticus; n = 18). We administered Pb dosages in the form of fishing weights (54–215 g) and monitored changes in blood lead concentrations, packed cell volumes, urine Pb concentrations, growth, and body condition over a 48-week period. Crocodiles exhibited a remarkable tolerance to exceptionally high Pb exposure over the duration of the study. Despite the lack of obvious clinical signs of Pb toxicity, elevated BPb concentrations were linked to lower PCVs, indicating anaemia across all treatment groups by week eight. However, crocodiles showed a sustained erythropoietic response which may be contributing to their resilience to acute Pb toxicity. While Pb exposure did not significantly affect body condition, it was associated with a discernible reduction in weight gain over the duration of the study. Our estimation of a 5.8–7.3-year timeframe for complete dissolution of the Pb fishing weights in the experimental crocodiles’ stomachs carries significant implications for wild populations, which are likely to be exposed to Pb for far longer than 48-week duration of this study.

This study utilized the methodology of digital soil mapping (DSM) to investigate the spatial prediction of toxic metals and their environmental covariates in the Ghorveh Plain, western Iran. The environmental covariates are defined as the factors that control the distribution of toxic metals at the geographical scale under investigation. They could be used for predicting the sources and monitoring of pollution. A total of 150 soil samples (0–30 cm) were analyzed for toxic metal concentrations and some soil properties. A comprehensive set of environmental variables was obtained from remote sensing imagery, DEM, and ancillary data, which were identified as likely to control the spatial distributions of toxic metals. The genetic algorithm was utilized to identify “all-relevant” environmental covariates for each toxic metal. Three machine learning algorithms, namely random forests (RF), cubist, and regression trees (RT), were employed to establish the statistical relationships between toxic metals and the environmental covariates. The RF model exhibited the most optimal prediction performance. All three models, particularly the RF, demonstrated robust performance, exhibiting minimal impact on the model’s functionality when confronted with alterations in the training and testing data. Consequently, the optimal model, RF, was integrated with a bootstrapping method to generate prediction and uncertainty maps. The soil properties and hydrologic factors were the primary variables influencing the spatial distribution of each toxic metal. This study indicates that the integration of DSM techniques with machine learning models and supplementary datasets offers a viable approach to the generation of maps for monitoring and prioritizing remediation measures in areas contaminated by toxic metals.

Karst water bodies are vital groundwater resources particularly vulnerable to pollution. Protecting their water quality requires documenting contaminants traditionally associated with anthropogenic activities (metals, nutrients, and fecal indicator bacteria) as well as emerging contaminants, such as antibiotic-resistant organisms (AROs) and perfluoroalkyl substances (PFAS). This study detected contaminants in karst-associated water bodies on the Yucatán Peninsula, including 10 sinkholes (cenotes) and one submarine groundwater discharge (SGD) site. The concentrations of metals (strontium, cadmium, nickel, lead), nutrients (phosphate, silicate, ammonium, nitrate, and nitrite), and fecal indicator bacteria (fecal coliforms, Escherichia coli) were consistent with previous reports, sometimes exceeding recommended standards for groundwater or the protection of aquatic life. This included elevated lead (80.3 µg/L) and nitrate (413 μmol/L) concentrations at two cenotes, and elevated E. coli levels (167 – 1800 CFU/100 mL) in five cenotes. Additionally, 34 antibiotic-resistant E. coli strains were identified in nine cenotes and most strains were multidrug-resistant. Perfluorooctanesulfonic acid (PFOS) and perfluorohexanoic acid (PFHxA) were also detected in eight cenotes and the SGD, with total PFAS concentrations from 0.68 to 10.71 ng/L. The absence of associations between contaminants and urban cover suggests karst hydrology influences contaminant cycling—stable isotope signatures (δ¹⁸O, δ²H) confirming that most systems are interconnected to regional groundwater flows, that could allow contaminants to travel long distances. The Yucatán Peninsula’s karst is an important freshwater reservoir used for consumption and recreation; the presence of contaminants and the karst’s vulnerability to their spread raises concerns and highlights the need for continued monitoring and conservation.

Pollution from past industrial activities can remain unnoticed for years or even decades because the pollutant has only recently gained attention or been identified by measurements. Modeling the emission history of pollution is essential for estimating population exposure and apportioning potential liability among stakeholders. This paper proposes a novel approach for reconstructing the history of polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) pollution from municipal solid waste incinerators (MSWIs) with unknown past emissions. The proposed methodology relies on the search for technical and operational data on the pollution source in archives, the extraction of representative data from the scientific literature, and the use of kinetic models of the formation and decomposition of PCDD/Fs within combustion chambers. This new methodological tool allows to estimate any MSWI’s stack emission and relative profile of seventeen PCDD/F congeners over time. The approach is validated through a case study of an MSWI in Switzerland. The modeled congener profile achieved a Pearson correlation coefficient of 0.98 with measurements in fly ash washwater. Additionally, the simulated soil quantity (1,115–1,419 gTEQ _WHO-2005 or 1,283–1,698 gTEQ_WHO-2022) agrees in order of magnitude with the estimated quantity from measurements (371 gTEQ _WHO-2005 or 425 gTEQ _WHO-2022).

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This study investigates airborne concentrations of six insecticides widely used on crops grown in agricultural, semi-urban, and rural areas of Bursa Province, Türkiye. Sorbent-impregnated passive air samplers (SIP-PASs), consisting of polyurethane foam (PUF) disks impregnated with XAD-2 resin, were deployed at ten strategically selected sites representing diverse agricultural and demographic profiles within the province. Analytes were quantified using gas chromatography–mass spectrometry (GC–MS) for depuration compounds and liquid chromatography–tandem mass spectrometry (LC–MS/MS) for target insecticides. Although this study focused solely on insecticides, future research should expand monitoring to include herbicides and fungicides—especially those applied to fruit crops—to provide a more comprehensive evaluation of airborne pesticide exposure. Spatial and temporal concentration patterns were analyzed, alongside Clausius–Clapeyron and back-trajectory analyses to assess temperature-driven volatilization and potential source regions. Health risks were evaluated for various age groups, with emphasis on children. The results offer new insights into CUP behavior and associated inhalation risks in intensively farmed regions. Average CUP concentrations were three times higher in agricultural areas than semirural, and nine times higher than rural zones, with peak levels in Ağaköy, Kestel, Demirtaş, and Mudanya. Concentrations were significantly elevated during warm periods. Temperature effects were evaluated using the Clausius–Clapeyron equation, while cluster analysis indicated long-range transport. Inhalation risk assessment showed hazard quotients below 1 and most lifetime cancer risk values under 10⁻⁶, indicating low health risks.

Dust palliatives are used to reduce fugitive dust in areas susceptible to erosion by wind and rain. In 2015, the Bureau of Land Management (BLM) temporarily approved the use of polymer-based dust palliatives during the construction and operation of a solar energy facility and, in 2019, on a mining access road in Clark County, Nevada. The areas treated with palliative are habitat to the desert tortoise. The desert tortoise consumes water opportunistically from puddles, saturated soils, or by the collection of precipitation on their carapaces. Since little is known about the toxicity of polymeric substances to the desert tortoise, the BLM is concerned with the exposure of the desert tortoise to palliative in stormwater runoff. The BLM collaborated with the US Geological Survey (USGS) to evaluate the transport of butyl acrylate vinyl acetate (BA-VA), the copolymer ingredient in the dust palliatives applied in the study, away from areas of application. BA-VA concentrations were measured in soils treated with palliative up to 90 days post-treatment, after which the copolymer became undetectable (< 0.55 mg/g). BA-VA concentrations in all stormwater samples within and outside treated areas were consistently below detection (< 0.20 mg/mL). Although stormwater and treated soils eroded from the solar facility application area were found to have BA-VA concentrations below detection (< 0.55 mg/g), it is likely that some BA-VA (parent or degradation product) was transported with suspended material. It is also likely that the amount of BA-VA transported away from areas of application was a small fraction of that applied.

This paper presents the results of a study of the physicochemical conditions and contamination of a peat deposit in a representative northern boreal bog with the persistent organic pollutants (POPs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB), and pentachlorophenol (PCP), as well as compounds from another organochlorine compounds, the chlorinated phenols (CPs). Despite the remoteness from the industrial sources of these compounds, a wide range of the organochlorine compounds were detected in the studied peat deposit. The maximum concentrations of HCB, PeCB, and PCP reached 9.4 ng/g, 0.5 ng/g, and 2.6 ng/g, respectively. Moreover, the total CPs content exceeded 1400 ng/g. It was established that the main pathway of the input of POPs into peat deposit was the atmospheric deposition of particulate matter (ash particulates) transported from local emission sources and sources located in low-latitude territories and adjacent regions. The low mobility of POPs, as well as the high sorption capacity of high-moor peats in relation to compounds with similar properties, lead to their concentration in the upper aerated 40 cm layer of the peat deposit, the formation of which coincides with the age of the "chloroorganic society." Factor and correlation analysis revealed that the key factor determining the distribution of these compounds in normally functioning bogs is the mineral component (ash content of peat and pore water mineralization).

Oil and gas extraction, refining, reforming and transport are important production activities mainly conducted in the Southern Patagonia region of Argentina. Several threats to natural ecosystems have been associated with this industry, most of them related to the increase in toxic metals and metalloids in the environment and biota. Birds of prey are widely used to assess metals and metalloids pollution in the environment. This study determined levels of selected trace elements including both essential and toxic metals in the blood of Crested Caracara (Caracara plancus) nestlings and evaluated relationships between the trace elements composition levels and the distance between nests and oil production plants and the prevailing wind in Southern Patagonia, Argentina. Pb, As, Zn, Se, Ni, Cu, Cr, Cd and V were determined by inductively coupled plasma-mass spectrometry. Two groups of trace elements were correlated according to the blood levels detected (As-V-Cr; Zn-V-Cr), suggesting a common source of exposure to these trace elements. The prevailing wind constituted a promising mechanism to explain an association between the oil pipe-derived trace elements and the exposure of nestlings. Nestlings showed elevated levels of As, Se, Cd, Ni and Zn, which were higher than reference levels reported for other raptor populations. These results indicate that nestling Crested Caracaras are exposed to toxic trace elements in Southern Patagonia. This is the first report of trace elements in the blood of Crested Caracara nestlings inhabiting Southern Continental Patagonia, Argentina, and provides baseline data of this contamination in this species.

The Province of Saskatchewan in western Canada is a global player when it comes to uranium (U) production. There are several active and decommissioned uranium mines in the northern region of the province, and new deposits continue to be discovered. Increases in U in the aquatic ecosystems surrounding uranium mining operations can lead to toxic effects on aquatic organisms. However, aquatic organisms only take up U when it is in its bioavailable form. Bioavailability of uranium is affected by such water quality variables as pH, dissolved organic carbon, and hardness and alkalinity. Hardness and alkalinity usually vary together and have often been examined in other studies in this fashion. The aim of this study was to investigate the effect alkalinity has on the toxicity of U to Daphnia pulex when hardness is kept constant and vice versa. The acute lethality effects after a 96 h exposure period were determined. The toxicity of U to D. pulex was highly dependent on hardness. At an alkalinity of 20 mg/L as CaCO₃, the 96 h LC₅₀ value for U increased from 170.1 to 4050 μg/L when the hardness increased from 20 to 180 mg/L as CaCO₃. A similar hardness effect on U toxicity was seen at higher alkalinity values. Alkalinity also had a significant effect on U toxicity as the 96 h LC₅₀ at a hardness of 20 mg/L as CaCO₃ increased from 170.1 to 1048.7 μg/L when alkalinity increased from 20 to 180 mg/L as CaCO₃. U speciation modeling using the chemical equilibrium program Visual MINTEQ revealed significant changes in U species present at different alkalinities, suggesting a possible explanation for the decrease in U toxicity.