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This study presents the level of organochlorine pesticide (OC) residues in human milk samples collected from donor mothers aged from 18 to 30 years old, from four cities in Eastern district of Saudi Arabia (Al-Hassa, Al- Khobar, Al-Jubail, and Al-Dammam). Pesticides residues were extracted from the samples and analyzed using GC-MS. The results showed that, only pp’DDE and p,pDDD, were found in 82.5% and 70% of analyzed samples respectively, the total DDT were at level of 0.37, 0.32, 0.30 and 0.46 μg/L in the four cities respectively and were far below the MRL of 50 μg/L (FAO/WHO). The estimated daily intake (EDI) of DDT ingested by infant weight 3.5 kg ranged between 0.06 and 0.10 μg/kg, which is less than the ADI issued by (EFSA, 2014). Lindane (γ-HCH) found in 91.25% of the analyzed samples at level of 0.37, 0.35, 0.35 and 0.29 μg/L. The EDIs of Lindane by infant were far below the ADI of 5 μg/kg bw/day. Dieldrin and Enderin were found in 27.5% and 58.8% of samples respectively and were lower than MRL issued by FAO/WHO, but the (EDI) was higher than the ADI issued by EFSA. The isomer A-heptachlor was detected in 51% of the samples, at levels were 15 times lower than the MRL issued by FAO/WHO, but EDIs by infants were 2–4 times higher than the ADI issued by EFSA. However, the results of the four studied areas in Saudi Arabia showed no statistically different among locations (p > 0.05). [ABSTRACT FROM AUTHOR]

To evaluate the maximum possible hazard of veterinary antimicrobial mixtures at doses accessible to humans, Sprague-Dawley male rats were orally dosed with a mixture of 26 commonly used veterinary antimicrobials for 90 consecutive days. The daily dosage of each component was 100 times (G1), 10 times (G2) and, 1 time (G3) of acceptable daily intake (ADI) in China. Hematology analysis and biochemical analysis found significant changes of several parameters, suggesting liver damage. Histopathological examination further indicated that mixtures of veterinary drugs at three levels caused obvious hepatotoxicity, and the severity of damage increased with dosage. LC-MS-based metabolomics analysis was carried out to detect metabolite changes in liver tissue. In G1, G2, and G3, 208, 165, and 195 differential accumulated metabolites (DAMs) compared with the Ctrl group were filtered, respectively. Similarly, RNA-seq helped us to filter a total of 183, 118, and 38 differentially expressed genes (DEGs) in G1, G2, and G3 compared with the Ctrl group, respectively. By integrating with the transcriptomic and metabolomic data, we revealed that mineral absorption, ascorbate and aldarate metabolism may be the major pathways affected by the veterinary antimicrobial mixtures in our study. This study provided useful data for the risk assessment of multiple chemicals. [Display omitted] • A mixture of 26 commonly used veterinary antimicrobials induced hepatotoxicity on rats at the dose of ADI level. • Possible major pathways affected by the veterinary antimicrobial mixtures were filtered. • Ugt1a1, Ugt2b15, and, Ugt2b35 were downregulated at three doses. [ABSTRACT FROM AUTHOR]

In malaria-endemic areas, where DDT is still used for vector control by indoor residual spraying (IRS), the concentrations of DDT in human blood and breast milk are high, and there are indications of human health impacts. To identify the possible avenues of exposure reduction, we created the concept of a Total Homestead Environment Approach (THEA). THEA characterizes the interactions between DDT, humans, and the biota within and around homesteads. One dietary route of human exposure and uptake of DDT, namely, chicken egg consumption, has to our knowledge never been studied. The ΣDDT in eggs from a DDT-sprayed village ranged between 5200 and 48,000 ng/g wm (wet mass), with a median of 11,000 ng/g wm. On a lipid mass-basis (lm), the mean ΣDDT for eggs from the sprayed village was 100,000 ng/g lm. The maximum egg concentration observed was three orders of magnitude higher than the median. The acceptable daily intake (ADI) was not exceeded based on the consumption of three eggs per week for a 60 kg person. This equates to an intake of 0.089 g DDT per person per year. Chicken egg consumption is therefore a possible target for exposure reduction, probably best achieved by reducing the DDT concentrations in soils. [ABSTRACT FROM AUTHOR]

The present study developed a new step-wise approach to estimate the potential human health risk of antibiotics in binary mixture for drinking water samples for two different sub-populations. Monte Carlo simulation based uncertainty analysis was performed to reduce uncertainty in risk assessment. Human health risk assessment studies were carried out using the acceptable daily intake (ADIs) for exposures of individual antibiotics considering point of departure (POD) and uncertainty factors (UFs). The estimated ADI values were used to estimate the predicted no effect concentrations (PNECs), at or below which no adverse human health effects are anticipated. Hazard quotient (HQ) in risk assessment was calculated as a ratio of environmental concentrations (ECs) and PNECs (EC/PNEC). The study showed that the average HQs values of individual antibiotics in adult and children were found below the acceptable limit, demonstrating no possible human health risk for both the subgroups. HI interaction values of antibiotics in binary mixture was calculated using HQ values of antibiotics. The study observed that the estimated HI interaction values of antibiotics in binary mixture was found to be less than 1 for both the sub populations, indicating no potential adverse effects on human health. Concentration of antibiotics was the primary contributor (>65%) to the overall variance in the uncertainty estimates for HQs of individual antibiotics in drinking water for adult and children. The co-occurrence of antibiotics in binary mixture for drinking water samples doesn't possess any possible risk on human health for the studied population. • First study on antibiotics risk in binary mixture by UESPA weight of evidence. • Use of pharmacological data for risk assessment of antibiotics in binary mixture. • Binary mixture of antibiotics under the studied condition do not possess any risk. • USEPA weight of evidence method can be used for risk assessment of antibiotics. • Concentration of antibiotic was major contributor to overall variance in risk estimate. [ABSTRACT FROM AUTHOR]