Bulletin of Environmental Contamination and Toxicology最新文献

Anthropogenic particles occur in various aquatic environments, and rainwater acts as a carrier of these contaminants by incorporating them into water droplets. To test the potential of rainfall to remove airborne particles, rainwater was collected three times during the rainy season in the municipality of Macapá, Amapá, Brazil. Chemical digestion and filtration protocols were applied to identify particles. A total of 225 ml of rainwater yielded 194 particles. Particle abundance increased with the number of preceding rain-free days, suggesting that rainfall may contribute to the atmospheric removal of these particles.

Paclobutrazol is used as both a fungicide and growth regulator in onion, its residue persistence raises concerns for food safety and environmental health. A field study was conducted to estimate the residues of paclobutrazol on onion crop. Two foliar sprays of Paclobutrazol 23% SC with 15 days interval were applied at recommended dose (X) i.e. 34.5 g a.i. ha^- 1 and 1.25X recommended dose i.e. 43.13 g a.i. ha^- 1 in onion, Samples were collected at different intervals to estimate dissipation and persistence of paclobutrazol. QuEChERS method was used to extract residues which were further estimated via LCMS/MS. Initial residues were observed to be 0.29 and 0.35 mg kg^- 1 in samples applied with X and 1.25 X dose. Residues of paclobutrazol reached below LOQ (limit of quantification) at 10th day at X dose and 15th days of sampling at 1.25X dose after last application. Residues of paclobutrazol were below the LOQ in mature onion and soil samples collected at harvest. Dissipation kinetics showed that paclobutrazol residues dissipated via first order kinetics at both the doses. T_1/2 (half-life) of paclobutrazol was calculated to be 4.57 and 5.04 days, at X Dose and 1.25 X Dose respectively, in green onion. Dietary risk assessment showed the hazard quotient (HQ) observed at both the doses was less than 1 for both adults and children.

Heavy metal contamination in coastal sediments presents ecological risks, particularly in rapidly developing regions like Southeast Asia. This study assesses the distribution, speciation, and environmental risk of cobalt (Co), nickel (Ni), arsenic (As), cadmium (Cd), and lead (Pb) in surface seagrass sediments from the Pulai River Estuary, Malaysia. Total and sequential extraction methods were employed to evaluate metal bioavailability. Results indicated that Ni (18.47 ± 1.37 µg/g) and Pb (17.79 ± 0.44 µg/g) were the most abundant elements in the total concentrations, whereas As (19.04 ± 0.70 µg/g) exhibited the highest concentration in the sequential extraction fractions. Sequential extraction results indicated mixed natural and anthropogenic sources, mainly from industrial discharges contributing to elevated As concentrations, while other metals remained in stable forms. Although geochemical indices of Enrichment Factor (EF), Geoaccumulation Index (I_geo), Contamination Factor (CF), and Pollution Load Index (PLI) generally classified the sediments as non-polluted, a comparison with the Sediment Quality Guidelines of Effect Range-Low (ERL) revealed potential biological risks associated with elevated Ni and As concentrations. These findings highlight the necessity for long-term monitoring and mitigation strategies to protect seagrass ecosystems in the Pulai Estuary.

This study reports a simple and efficient dispersive solid-phase extraction (DSPE) method using phosphonate ester-functionalized poly(amidoamine) (PAMAM) dendrimer-coated magnetic nanoparticles for the trace determination of Co(II) and Cr(III) in environmental samples by flame atomic absorption spectrometry (FAAS). The nanoparticles were synthesized and characterized by NMR, FT-IR, SEM, and TGA analyses. Under optimized conditions, detection limits were 0.8 µg L⁻¹ for Co and 1.9 µg L⁻¹ for Cr, with linear calibration ranges of 2.5-250 µg L⁻¹ and 5.0-500 µg L⁻¹, respectively. Compared with direct FAAS, the enhancement factor (EF) was 110 for Co and 204 for Cr. Recovery tests in spiked tap water and black tea infusions yielded recoveries of 79% to 114%, confirming the method's precision and applicability in real matrices. This approach provides a cost-effective and reliable alternative to advanced instrumental methods and demonstrates the potential of functionalized magnetic sorbents for trace metal monitoring in environmental and food analysis.