Springer Science and Business Media LLC

Florida apple snails (Pomacea paludosa) were exposed to three concentrations of copper (Cu), in water (8 μg/L, 16 μg/L, 24 μg/L), for one generation to examine uptake and the effects on survival, growth, and reproduction of the F0 generation and survival, growth, and whole body Cu of the F1 generation. During a 9-month Cu exposure, apple snails exposed to 8–16 μg/L Cu had high Cu accumulation (whole body, foot, viscera, and shell) and significantly reduced clutch production (8–16 μg/L) and egg hatching (16 μg/L). Apple snails exposed to the 24 μg/L Cu had low survival and the treatment was therefore terminated. Concentrations of minerals (Na+, K+, Mg2+, Ca2+) in tissues were maintained regardless of Cu exposure, but the distribution of Cu in the body of snails differed, depending on exposure concentrations. Higher exposure concentrations resulted in a greater percentage of Cu accumulated in the viscera of the snail. Copper exposure to the F0 generation did not affect the survival, growth, or whole body Cu concentrations in the F1 generation. These finding are significant, given the importance of the Florida apple snail in the Everglades food chain. Changes in the abundance of apple snail populations, as a result of Cu exposure, could ultimately affect foraging success of predators.

Toxic effects of the herbicides dinoseb and paraquat, both individually and combined, on embryonic development and hatching ofFasciola hepatica miracidia were assessed by exposing the eggs to varying concentrations (0–20 μg/ml) of each of the herbicides. The results showed that dinoseb has an LC50 value of 4.3 μg/ml, paraquat has an LC50 of 4.9 μg/ml and the mixture of both dinoseb and paraquat has an LC50 of 7.1 μg/ml. Based on the LC50 values, dinoseb is slightly more toxic than paraquat on the tested organisms. The results also showed that the mixture of dinoseb and paraquat is significantly less toxic than the individual pesticides. Eggs ofF. hepatica cultured in either dinoseb or paraquat both individually and combined showed a delay of embryonic development and hatching of the miracidia. Eggs cultured in 0–2 μg/ml of dinoseb, paraquat and their mixture, fully embryonated and hatched within 14–16 days, while eggs cultured in 4–6 μg/ml of the same herbicides showed a delay of four days for embryonic development and hatching of their miracidia.

Parabens are widely used as preservatives in personal care products, foodstuffs, and pharmaceuticals. Concerns have been raised regarding the potential endocrine disruption effects of parabens. In the present study, the urinary concentration of four common parabens, including methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP), in 100 Iranian adolescents randomly referring to health services centres were analyzed using GC/MS. The association of sociodemographic and lifestyle variables, collected through questionnaire, with the concentration of parabens also were studied. Median concentrations of MP, EP, PP, and BP were 92.21, 8.46, 12.26, and 8.42 µg/g creatinine, respectively. There was a strong positive significant correlation between MP and PP (r = 0.694) and moderate to a weak correlation between the other parabens. The concentration of urinary MP in females was significantly higher than those in male (p = 0.021). There was a significant negative association between different BMI groups and MP and EP. There also was a positive significant association between the MP and age, and between MP, EP, and PP, and tobacco use. Although the estimated daily intake of the parabens was lower than the Acceptable Daily Intake, it was higher than those reported in other countries. This confirms the widespread exposure of Iranian adolescents to the paraben compounds and their association with sociodemographic factors. This was the first study reporting the urinary parabens level in Iranian adolescents, and the data can be used as a basis for assessing the risk of exposure to parabens in the Iranian population in future studies.

Bisphenol A (BPA) and bisphenol S (BPS) are implicated in the development of metabolic disorders, such diabetes mellitus. However, the epigenetic mechanism underlying the pancreatic β-cell dysregulation for both BPA/BPS needs clarification. This exploratory study was designed to investigate whether embryonic exposure to low BPA/BPS concentrations impair early pancreatic β-cell differentiation as well as DNA methylation in its gene expression profile using an in vivo model, zebrafish. Zebrafish embryos were exposed to 0, 0.01, 0.03, 0.1, 0.3, and 1.0 µM BPA/BPS at 4-h post fertilization (hpf) until 120 hpf. BPA/BPS-induced effects on pancreatic-related genes, insulin gene, and DNA methylation-associated genes were assessed at developmental stages (24–120 hpf), while glucose level was measure at the 120 hpf. The insulin expression levels decreased at 72–120 hpf for 1.0 µM BPA, while 0.32 and 0.24-fold of insulin expression were elicited by 0.3 and 1 µM BPS respectively at 72 hpf. Significant elevation of glucose levels; 16.3% (for 1.0 µM BPA), 7.20% (for 0.3 µM BPS), and 74.09% (for 1.0 µM BPS) higher than the control groups were observed. In addition, pancreatic-related genes pdx-1, foxa2, ptfla, and isl1 were significantly interfered compared with the untreated group. Moreover, the maintenance methylation gene, dnmt1, was monotonically and significantly decreased at early stage of development following BPA exposure but remained constant for BPS treatment relative to the control group. DNMT3a and DNMT3b orthologs were distinctively altered following BPA/BPS embryonic exposure. Our data indicated that embryonic exposure to low concentration of BPA/BPS can impair the normal expressions of pancreatic-associated genes and DNA methylation pattern of selected genes in zebrafish early development.