Objectives The American-Vietnam War ended over 35 years ago, but dioxins still remain in human tissue and Vietnam's environment. The main objective of this study was to assess the correlation between dioxin concentration in soil, sediment and breast milk in one of the areas sprayed with herbicide, namely Cam Chinh commune, Quang Tri province, using a geographic information system (GIS). Methods The concentration of polychlorinated dibenzop-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in soil, sediment and breast milk samples was determined and the data analyzed using the geostatistical log-normal Kriging algorithm. Results The mean dioxin levels in soil and breast milk in the sprayed area were significantly higher than those in the non-sprayed area. The distribution pattern of PCDDs and PCDFs in soil was different, and there were no significant correlations between the estimated dioxin levels in soil obtained by the Kriging method and those in breast milk. Conclusions The possibility remains that another exposure route, such as exposure to herbicides used during the Vietnam War, might affect dioxin levels in breast milk, although more soil data are needed to make more reliable geographical estimations.

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La Perouse (Soya) Strait, 40 km in width, separates Hokkaido Island (Japan)

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The main objective of this paper is to demonstrate how Environmental Sensitivity Index (ESI) maps are made. The efforts have been based on the on-site research and various kinds of lessons from the oil spill from the Russian tanker Nakhodka that happened in January 1997. In September 1999 and March 2000, 168 km of the oil-stranded shoreline was surveyed. This survey was conducted by using the Shoreline Oiling Summary (SOS) Form developed by Environment Canada in 1994. Eighty oiled sites were selected for this survey, and oil residue was found in over 80% of the study sites. It has become clear that the amount of residual oil depends on these four parameters of the survey: (1) types of shoreline sediment, (2) scale of the shoreline, (3) existence of sheltering rocks, and (4) slope of the shoreline. These results almost support the correctness of the ESI guideline developed by the National Oceanic and Atmospheric Administration (NOAA). This guideline, however, is dependent mostly on the calcification of the sediment; for developing ESI maps, parameters 2 and 4 are inevitably ignored. This paper presents one style of an ideal ESI map based on ArcView® 3.2, one of the common GIS platforms.