Archives of Environmental Contamination and Toxicology最新文献

In general, mercury (Hg) undergoes biomagnification in aquatic systems. The absence of Hg biomagnification in a certain aquatic environment constitutes an exceptional finding and this seems to be the case for Sepetiba Bay, in Rio de Janeiro state (RJ), Brazil. There are three distinct ecological populations of Guiana dolphins in the Sepetiba Bay (SB)-Ilha Grande Bay (IGB) Complex, inhabiting: (1) the inner part of SB; (2) SB entrance; and (3) IGB. In addition, there are two other delphinid species, rough-toothed dolphin and Atlantic spotted dolphin, that feed on the SB-IGB Complex. Considering the widely employed use of cetaceans as sentinels of environmental contamination by bioaccumulative toxicants, we have biopsy sampled individuals of the abovementioned ecological populations/species for measuring skin Hg concentrations. Two Bryde's whales and one humpback whale were biopsied in the SB-IGB Complex as well. Skin Hg concentrations [μg g^-1 dry weight (dw)] of Guiana dolphins were the highest in IGB, followed by SB entrance and the inner part of SB (0.99-5.47; 0.09-6.00; 0.08-2.22). Considering all species investigated in the present study, skin Hg concentrations were found in the following order: humpback whale < Bryde's whale < Guiana dolphins from SB inner part < Guiana dolphins from SB entrance < Guiana dolphins IGB = Atlantic spotted dolphins < rough-toothed dolphins. The skin Hg concentrations found in Guiana dolphins from the inner part of Sepetiba Bay (0.08-2.22) and rough-toothed dolphins from the SB-IGB Complex (1.26-20.0) are among the lowest and highest ever reported for dolphins worldwide, respectively.

Pesticides have posed health risks to consumers and the ecosystems in different parts of the world, including Ethiopia, and researchers recommend continual assessments of pesticide residues in food items and ecosystems to know the level of risks. This study aimed to quantify the pesticide residues in samples of cabbage and fish and their risks to humans and the ecosystems. The cabbage samples were collected from April to May 2023 from 3 market centers, and the fish samples were collected in June 2023 from two fish ponds of Fogera District of Ethiopia using appropriate sampling procedures, extracted using the modified QuEChERS methods, and analyzed using a triple quadrupole GC/MS technique to quantify the pesticide residues and level the risks to humans and the ecosystems. The findings of the present study confirmed that all the samples of cabbage and fish were contaminated with pesticide residues. More than 44% and 37% of pesticide residues detected in both cabbage and fish samples were organochlorine and organophosphate pesticides, respectively. Furthermore, 92.86% of the pesticide residues and 96.43% of the maximum pesticide residues in cabbage exceeded the MRL and the TQ set by the Codex Alimentarius Commission. The sum total hazard indices of the pesticide residues in the cabbage (22.320) and fish (43.071) were much higher than the threshold value. Though Fogera District is a potential area for fish production in ponds, agricultural pesticides are a threat to the sector. Establishing an efficient system of monitoring for the pesticide supply chain and application procedures, choosing the appropriate pesticide types, timing in spraying, and establishing pesticide-free buffer zones are crucial steps in mitigating the negative effects of pesticides in the area.

This study focuses on the "El Lavadero" tailings deposit, a mining environmental liability (MEL) located near the town of San Felipe de Jesús, Sonora, in northwest Mexico. The objective was to determine the total arsenic (As) content, its granulometric and geochemical distribution, as well as its mobilization capacity and bioavailability. The results from oxidized and unoxidized tailings showed low potential of hydrogen (pH) values (2.4-5.7) and high concentrations of total arsenic (8235-36,004 mg kg^-1), predominantly in the finer granulometric fractions (< 0.05 mm). Arsenic also prevails in the finest fraction of agricultural soil (> 2 mm). These fine particles could present adverse environmental effects due to their potential to be transported by leaching and water suspension. In contrast, arsenic in the effluent sediments is primarily found in the coarser fraction (> 2 mm). A significant proportion of arsenic in the tailings (5-40%) was found in the non-residual geochemical fractions (I + II + III) (1106-7675 mg kg^-1), indicating potential for mobilization and bioavailability. Depending on environmental conditions (redox potential and pH), arsenic can redissolve and exhibit high mobility in abiotic media, which may ultimately impact the environment and human health. Therefore, it is crucial to rehabilitate the "El Lavadero" MEL to prevent further environmental damage. This study provides useful information to understand some phenomena in other global mining environmental liabilities, such as mobilization and bioavailability of arsenic and its possible impact on the surrounding environment and biota, contributing to the worldwide research of ecosystems polluted by mining activity, especially in arid and semi-arid climates.

Isocyanates are used as raw materials for polyurethane foams, paints, and building materials. The isocyanates can cause acute adverse health effects such as irritation of the respiratory tract, skin, and eyes, and induce asthma and sick house syndrome. However, investigations into the potential sources and risk assessments of indoor isocyanates are limited. Thus, this study aimed to determine the sources and exposure routes of isocyanates and to assess their risk in indoor environments. The results showed that household products, such as infant chairs, mattresses, and polyurethane foam spray, used in indoor environments are potential sources of atmospheric isocyanic acids (ICA). Toluene diisocyanate and methyl isocyanate pose relatively high risks to indoor environments. Total concentrations of isocyanates ranged from 38.2 to 1570 ng g^-1 in infant chairs, mattresses, and spray polyurethane foams. The indoor products can be indoor sources of ICA because emission rates of ICA from household products were observed in all products (0.0536-1.37 ng g^-1 d^-1). Field observations showed that isocyanate concentrations in house-dust samples ranged from 0.194±0.126 (ethyl isocyanate) to 70.1±67.8 (ICA) ng g^-1. Atmospheric isocyanate concentrations ranged from 0.0030±0.020 (propyl isocyanate) to 26.0±14.3 (ICA) ng m^-3. An estimation of human exposure demonstrated that air inhalation was the major route of isocyanate exposure. The minimum margin of exposure values of methyl isocyanate and toluene diisocyanate were 523 and 655, respectively, for children, indicating that they may pose a relatively high risk.

In order to investigate the distributions and possible dispersion mechanism(s) of naturally occurring radioactive materials (NORMs: ²²⁶Ra, ²³²Th, and ⁴⁰K) from coal-based brick kilns, a systematic set (n = 60) of coal, ash, surface-soil, and subsurface soil samples were analyzed. High-quality analytical data of U, Th and K obtained from HPGe detector and TRIGA Mark-II research reactor-based neutron activation analysis were converted to the corresponding radioactivities. Average (n = 10) radioactivities of ²²⁶Ra, ²³²Th, and ⁴⁰ K in coal samples were 15.6, 16.7, and 145.5 Bq.kg^-1, respectively, where only ⁴⁰ K surpassed the corresponding global mean value. Average (n = 10) radioactivities of ²²⁶Ra, ²³²Th, and ⁴⁰ K in ash samples were 62.7, 88.5, and 521 Bq.kg^-1, respectively, where only ²²⁶Ra was within the established limit. In soil samples, average (n = 40) activities of ²²⁶Ra, ²³²Th, and ⁴⁰ K were 62.7, 95.1, and 641 Bq.kg^-1, respectively, which have surpassed the corresponding worldwide mean values. The observed differences in activity levels between soil samples collected near and far from the kilns, as well as between topsoil and subsoil samples, suggest the presence of distinct transport mechanisms for NORMs within the pedosphere. Dispersions of NORMs from the brick kilns to the ambient pedosphere are largely governed by aerodynamic convection and hydrodynamic leaching. These mechanisms are also influenced by geochemical mobility and relative solubility of NORMs, as well as factors such as rainfall patterns and wind-flow direction. Radiological indices invoke long-term carcinogenic-risks, whereas aerodynamic convection of finer particles (coal fly ash) from chimneys can cause significant health hazards to the nearby dwellers. Scientific processes as well as public awareness are essential to mitigate the risks.

Understanding the relationship between the aerobic transformation of organic matter (OM) and the bioavailability of lead to plants may allow the safe application of organic fertilizers (OF) in agriculture. The present study aimed to elucidate the relationship of different OM structures with Pb, revealing the action of OF (poultry litter) on Pb dynamics, presenting the effects of OM transformations on bioavailability and transfer to vegetables produced in tropical mountain agroecosystems (TMA). The association of Pb with hydrophilic structures (CAlk-O and CAlk-di-O) during the aerobic transformation of poultry litter (PL) contributes to the increase in the water-soluble form of this metal (3.17-15.30%). The structural changes promoted by the transformation of OM, in addition to reducing the adsorption capacity of Pb in PL (Kd reduction from 1135.50 to 87.49), favor the formation of outer-sphere complexes. PL that have a more labile structure, i.e., those that are less humified, have greater affinity for Pb. The greater affinity of Pb for labile structures that are preserved in PL during OM transformations contributed to its increase and transport to edible plant parts. Considering the edible parts of vegetables grown in TMA and fertilized with fresh PL, 100% of broccoli, 91.78% of cabbage, 80.00% of tomato, 65.96% of parsley, 49.19% of lettuce, and 32.88% of cauliflower showed Pb contamination that exceeded the permitted level. Therefore, OF contributes to lead contamination of food produced in TMA, representing a risk to human health. Studies are needed to propose additional treatments for this residue before its use.

Removing lowermost dams can reestablish fish passage on Great Lakes tributaries. This can increase the transfer of contaminants from anadromous fish to piscivorous wildlife upstream; however, concentrations of bioaccumulative contaminants in Great Lakes fish have decreased over the last several decades. We analyzed concentrations of PCBs and the toxic equivalence (TEQs) calculated from PCBs, DDTs, other organochlorine pesticides, and PBDEs in the plasma of bald eagle nestlings above and below lowermost dams on five river systems in Michigan from 1999 to 2013. We examined relationships between contaminants and metrics of reproductive success from 1997 to 2018, including the effects of year and location relative to the lowermost dam. Σ₂₀PCB and p,p'-DDE were important in characterizing differences in contaminant mixtures above and below dams. Concentrations of contaminants were generally greater below dams than above. There were generally greater nest success and more nestlings per nest below dams, but nest location explained little variability (R² values = 0.03-0.15). Neither Σ₂₀PCB nor p,p'-DDE was a significant predictor of 5-year productivity means by river reach despite concentrations exceeding previously established effects thresholds for healthy bald eagle populations in the Great Lakes (≥ 1 nestling/nest). Our study indicates that dams may continue to reduce the upstream movement of contaminants to bald eagles, but at the measured concentrations, contaminants did not impair productivity and reproductive success as indicated by nestlings per nest. Additional information about population dynamics could clarify population-level effects of contaminants on bald eagles and to what degree these populations are self-sustaining throughout the Great Lakes.