Environmental Toxicology and Chemistry最新文献

Elevated concentrations of toxic cationic aluminum (Al_i) are symptomatic of terrestrial and freshwater acidification and are particularly toxic to salmonid fish species such as Atlantic salmon (Salmo salar). Speciated metal samples are rarely included in standard water monitoring protocols, and therefore the processes affecting Al_i dynamics in freshwater remain poorly understood. Previous analysis of Al_i concentrations in Nova Scotia (Canada) rivers found that the majority of study rivers had concentrations exceeding the threshold for aquatic health, but a wide-scale survey of Al_i in Nova Scotia has not taken place since 2006 (Dennis, I. F., & Clair, T. A., 2012, Canadian Journal of Fisheries and Aquatic Sciences, 69(7), 1174-1183). The observed levels of dissolved aluminum in Atlantic salmon (Salmo salar) rivers of Atlantic Canada have potential serious and harmful effects for aquatic populations. We present the findings of the first large-scale assessment of the Al_i status of Nova Scotia rivers in 17 years; we measured Al_i concentrations and other water chemistry parameters at 150 sites throughout the Southern Uplands region of Nova Scotia from 2015 to 2022. We found that Al_i concentrations exceeded toxic thresholds at least once during the study period at 80% of the study sites and that Al_i concentrations increased during the study period at all four large-sample study sites. Modeling of relationships between Al_i concentrations and other water chemistry parameters showed that the most important predictors of Al_i are concentrations of the dissolved fractions of Al, iron, titanium, and calcium, as well as dissolved organic carbon and fluoride. We developed a fully Bayesian linear mixed model to predict Al_i concentrations from a test data set within 15 μg/L. This model may be a valuable tool to predict Al_i concentrations in rivers and to prioritize areas where Al_i should be monitored. Environ Toxicol Chem 2024;00:1-12. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Excessive dietary metal intake from crops grown on contaminated urban dumpsites poses a global health risk to consumers. We evaluated the health risk to adult and child consumers from dietary exposure to metals and metalloids in crops cultivated at the Mbale (Uganda) dumpsite centre. Thirteen crop types grown on the dumpsite soil were sampled and analyzed for concentrations of 11 metals: Fe, Al, Zn, Mn, Cu, Pb, Cr, Hg, Co, Ni, Cd, and two metalloids: Se and As. Different proportions of the crops were combined into 12 meal classes to simulate the diets of residents and estimate noncancer and cancer risks. The findings indicated that most individual crop types and simulated diets lacked sufficient selenium for bodily functions. Furthermore, their metal accumulations exceeded the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) permissible limits (mg/kg) for Al (20), Fe (100), Ni (10), Cu (20), Mn (10), Pb (0.3), Se (0.05), and Zn (99.4). The four most abundant metals in the various crop types and diets were Al, Fe, Mn, and Zn. A positive correlation between the metals in the crops indicated a common origin, which could possibly be the dumpsite soil. The chronic dietary intake (CDI) of metals was higher in children, and thus children faced higher noncancer and cancer risks compared with adults. The overall CDI values for each metal ranged from 0.000718 to 2.171 in adults, and 0.00125 to 3.781662 in children, which is approximately 1.74 times higher in children than in adult consumers. The noncancer and cancer risks ranged from moderate to high with Co, Cr, Fe, Mn, and Zn being mostly responsible for the high noncancer risks, and Al being the predominant contributor to cancer risks. The total noncancer risk levels equally ranged from moderate (1.4-3.3) for adults, and moderate to high (2.4-5.7) for children; the cancer risks were moderate to high in adults, with Al contributing to between 68% and 92% of the total risks across the 12 meal classes. Overall, CDI values and noncancer and cancer risks were all higher in children than in adults. The vegetables Amaranthus hybridus, Vigna unguiculate, Amaranthus dubius, and Cucurbita maxima significantly contributed to the high noncancer risk to both adults and children, particularly when they constituted 40% or more of the meal. Four additional vegetables (Cocorhrous olitorous, Brassica oleracea, Amaranthus cruentus, and Gynandropsis gynandra) also posed a high risk to children when consumed in large quantities. Our results highlight the urgent need to develop regulatory frameworks and/or rigorously enforce existing land and food governance policies to protect consumers' health from unsafe metal concentrations in crops grown on dumpsites. Environ Toxicol Chem 2024;00:1-17. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.