Predictors of Serum Dioxins and PCBs among Peripubertal Russian Boys

Background: Although sources and routes of exposure to dioxins and polychlorinated biphenyls (PCBs) have been studied, information regarding exposure among children is limited. Breast-feeding and diet are two important contributors to early life exposure. To further understand other significant contributors to childhood exposure, we studied a cohort of children from a city with high environmental dioxin levels. Objectives: We investigated predictors of serum concentrations of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs)/co-planar PCBs (C-PCBs), toxic equivalents (TEQs), and PCBs among 8- to 9-year-old boys in Chapaevsk, Russia. Methods: We used general linear regression models to explore associations of log10-transformed serum concentrations of PCDDs/PCDFs/C-PCBs, TEQs, and PCBs at study entry with anthropometric, demographic, geographic, and dietary factors in 482 boys in Chapaevsk, Russia. Results: The median (25th, 75th percentile) concentration for total 2005 TEQs was 21.1 pg/g lipid (14.4, 33.2). Boys who were older, consumed local foods, were breast-fed longer, and whose mothers were employed at the Khimprom chemical plant (where chlorinated chemicals were produced) or gardened locally had significantly higher serum dioxins and PCBs, whereas boys with higher body mass index or more educated parents had significantly lower serum dioxins and PCBs. Boys who lived less than 2 km from Khimprom had higher total TEQs (picograms per gram lipid) [adjusted mean = 30.6; 95% confidence interval (CI), 26.8–35.0] than boys who lived greater than 5 km away (adjusted mean = 18.8; 95% CI, 17.2–20.6). Conclusions: Our findings suggest that there are specific local sources of dioxin and PCB exposure among children in Chapaevsk including maternal gardening, consumption of locally grown food, and residential proximity to the Khimprom plant

Usage of spatial lattice metal structures as roofing for mechanical equipment rooms of hydroelectric power stations

The paper focuses on technical analysis of spatial attice structures used in roofing of mechanical equipment rooms of hydroelectric power stations in Russia. The analysis reveals that spatial structures of “Markhi” type are used most frequently there and shows their advantages and disadvantages. The authors put forward their own solution for combining advantages of spatial spatial lattice roofing structures with those of truss frames with gusset plate units. The solution is aimed at enhancing the safety and reliability of hydraulic engineering constructions with no changes in accuracy requirements to their manufacturing. The authors also introduce their model of a spatial lattice roofing unit and give an account of its reliability and strength based on software system calculations

Usage of spatial lattice metal structures as roofing for mechanical equipment rooms of hydroelectric power stations

The paper focuses on technical analysis of spatial attice structures used in roofing of mechanical equipment rooms of hydroelectric power stations in Russia. The analysis reveals that spatial structures of “Markhi” type are used most frequently there and shows their advantages and disadvantages. The authors put forward their own solution for combining advantages of spatial spatial lattice roofing structures with those of truss frames with gusset plate units. The solution is aimed at enhancing the safety and reliability of hydraulic engineering constructions with no changes in accuracy requirements to their manufacturing. The authors also introduce their model of a spatial lattice roofing unit and give an account of its reliability and strength based on software system calculations