•Pesticides were analysed in the urine of Slovenian mothers and their 7 year-old children.•The concentrations of most OPs and PYRs were higher in children than in their mothers.•The concentrations of ...most OPs and PYRs in mothers and children were correlated.•The parathion metabolite was the one in highest concentration in mothers and children.•The estimated daily intakes of OPs and PYRs did not show adverse health effect risks.
The present study reports one of the few cases in which organophosphate (OP) and pyrethroid (PYR) pesticide human exposure is evaluated in family contexts by the analysis of mother/child pair samples. Urinary concentrations of 6 organic metabolites of organophosphates and 2 pyrethroids were measured in mothers and their 7-to 8-year-old children (n = 168) in a general population from the central area of Slovenia. The results were adjusted for specific gravity and creatinine.
The most abundant OP metabolite in children was 4-nitrophenol (PNP) (median 0.7 ng/ml) and in mothers (0.45 ng/ml), representing parathion exposure. 3-Phenoxibenzoic acid (3-PBA) (0.26 ng/ml), the general metabolite of pyrethroids, and 3,5,6-trichloro-2-pyridinol (TCPY) (0.16 ng/ml; chlorpyriphos) were the second most abundant compounds in children and mothers, respectively. The geometric mean specific gravity adjusted concentrations of OPs and PYRs were statistically significantly higher in children than in their mothers (between 3% and 24% higher), with the exception of TCPY (26% lower). All OP and PYR metabolites found in higher concentration in children showed significant positive correlations with the metabolite concentrations found in the mothers (p < 0.05 and 0.01), involving the fact that higher maternal concentrations were associated with higher children levels.
These differential mother-children distributions and significant correlations were observed for the 2 types of pesticides studied, OPs and PYRs, which have different chemical properties. This agreement is consistent with the incorporation of the pesticides because of the general activities developed in the family context, instead of pesticide-dependent specific inputs.
Comparison of the estimated daily intakes with the acceptable daily intakes of all detected metabolites revealed no significant risk of adverse health effects from exposure to these pesticides.
The traditional rationale for developing nuclear fusion as an energy source has been that it will be practically inexhaustible, environmentally benign, and safe. Its great potential to become a major ...component of the global energy budget in the 21st century notwithstanding, fusion has certain features that make the study of its safety and environmental problems a necessity. Activation of reactor structural materials from plasma neutrons and existence of significant tritium inventories in the fuel processing plant of D-T fueled fusion reactors are the principal safety issues associated with fusion energy. The focal point of this work has been the development of a comprehensive, multi-step methodology in order to incorporate the safety concerns associated with the radiologically hazardous tritiated inventories present in the fusion power plant into the system design process. This methodology includes: (a) the development of a dynamic process-simulation code (TRIDYN, for TRItium DYNamics) in order to assess both the transient and steady-state behavior of the fuel processing system, (b) identification of the reactor-plant sub-systems that are most vulnerable to release of tritium, and calculation of the tritium inventories that could be mobilized in the case of a catastrophic failure, and (c) optimization of the design of the vulnerable sub-systems to minimize releasable tritium inventories. This methodological framework is, more generally, applicable to industrial plants characterized by the presence of significant amounts of hazardous materials. In this work, it has been applied to the fuel processing system envisaged for the first generation of power-producing magnetic fusion reactors. A simplified approach for modeling packed cryogenic distillation columns such as the ones used for separation of the hydrogen isotopes in fusion reactors has been introduced, and other short-cut methods for calculating the tritiated inventories in each sub-system are presented. The results of the TRIDYN code have been checked for accuracy against experimental and simulation data from existing pilot-plant facilities. Parametric studies using TRIDYN have identified the relationship between vulnerable tritium inventories and reactor system parameters such as fusion power, tritium burnup fraction in the plasma, and the purity requirement on the tritium product of the separation system. Finally, the application of the safety optimization algorithm to critical parts of the system, such as the isotope separation system, has shown how different system design configurations may impact the overall safety of the fuel processing plant.
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