Search

Dietary consumption of fish is the greatest contributor to dioxin exposure of the general population in Japan. Unlike with other routes of exposure to dioxins, exposure via foodstuffs does not necessarily occur from local sources. Clarifying the distribution of fish from the catch area to local markets helps to control dioxin exposure from the head of the distribution chain down. We analyzed the data from 30 major central wholesale fish markets to determine both the market share of fish by catch area and the market share of major fish types in fish consumption markets. Probabilistic estimation of dietary exposure of the general population to dioxins in fish was conducted in seven regions in Japan. Probabilistic density functions (PDFs) were assigned to express the variability of data from monitoring of dioxin levels in fish by catch area or by fish type. From histograms of dioxin levels in fish by catch area, the mean and 5th to 95th percentile range of dietary exposure to dioxins in the region with the largest 95th percentile value were estimated, respectively, as 55.5 and 12.9-172.9 pg-TEQ/day. No statistically significant differences in dietary exposure to dioxins in fish were observed among the seven regions. Some specific coastal catch areas and some types of fish that had a greater impact than others on exposure were pinpointed for each region. [ABSTRACT FROM AUTHOR]

Toluene is a chemical substance whose release to the atmosphere is the largest among the pollutant release and transfer registers (PRTR) chemicals and is regarded as one of the major indoor air pollutants. We have developed a method of estimating the distribution of personal exposures of Japanese residents, combining exposure from indoor and outdoor sources. Personal exposure was divided into contributions of indoor and outdoor sources. Ambient toluene concentration was estimated for a 5 x 5 km square grid spatial resolution using the National Institute of Advanced Industrial Science and Technology-atmospheric dispersion model for exposure and risk assessment (AIST-ADMER) using PRTR emission data. The contribution of indoor sources was assumed to be the difference between indoor and outdoor concentrations, which was regarded to have a lognormal distribution. The health risk from toluene exposure in Japanese residents is expressed as the number of people whose personal exposure exceeded the reference values, which were set on the basis of a review of epidemiological studies. Finally, a risk-reduction strategy is suggested according to the proposed principle of risk management.