In order to clarify the origin of lead contamination in gas station, the distribution and the existence of lead in gas station site soil have been investigated. The gas station site soils were collected in accordance with the Soil Contamination Countermeasures Act (SCCA). The total concentration of lead in the site soils were in the range from 8.9 to 4520 mg/kg(n＝22). The lead concentration of the 10 samples were exceed the elution standards based on the SCCA, and the 8 samples were exceed the content standards by 1 mol/L-HCl elution test. It was found that the criteria of SCCA is not enough to identify the origin of lead pollution. The chemical species of anthropogenic lead contaminated in the soil are known to present in such as carbonate, sulfide, hydroxide, and organic complexes. Thus, the existence of lead in the gas station site soils have been estimated by sequential chemical extraction. A large amount of lead eluted from the soil with a high concentration of lead by sequential chemical extraction, but the elution of lead from a low concentration soil was less. These lead easily eluted from gas station site soil was estimated to be anthropogenic origin, but in the samples analyzed were considered to also include those of natural source (HB17-1, HB17-2). It was not possible to determine exactly the origin of the lead contamination in such a chemical extraction. Therefore, the analysis of the origin of contaminated lead using its stable isotopes have been performed. From the historical trends of the lead isotope ratios that has been used in Japan since the Meiji Restoration, if the ²⁰⁷Pb/²⁰⁶Pb ratio is greater than or equal to 0.86, it is assessed that the lead is originates from anthropogenical contamination. On the basis of the lead isotope ratio, 8 samples out of 22 gas station site soils were estimated to be anthropogenically contaminated by lead.

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The sum of 9 PFCs concentrations in water of Lake Biwa was 10.6 ～13.5 ng/L and little differences among 4 sites of northern basin of Lake Biwa (12B, 17A, 17B, 17C') in August 2011. The order of average PFCs composition in 7 sites of all over the Lake Biwa was PFOA ＞PFNA ＞PFHpA ≧PFHxA ＞PFOS ＞PFDA ＞PFHxS ＞PFUnDA ≧PFBS, little differences among the sites. The concentration range (average) in water of 12 rivers around Lake Biwa was 0.48 ～59.2(26.4) ng/L and large differences among the 12 rivers. The order of average PFCs composition in water of the 12 rivers was PFOA ＞PFNA ＞PFOS ＞PFHxA ≧PFHpA ＞PFDA ＞PFBS ＞PFHxS ＞PFUnDA, slightly different from that in Lake Biwa. Seasonal changes of PFCs concentrations and compositions in water of 3 sites of Lake Biwa (6B, 12B, 17B) were little in May, August, November 2012 and February 2013. The sum of 15 PFCs concentration range (average) in sediment of Lake Biwa was ND ～4.42 (1.51) ng/g dry wt. in May ～December 2013. The PFCs concentration was high in clay-like sediment of deep central area of northern basin of Lake Biwa. There were no differences between southern and northern basins of Lake Biwa in the PFCs composition of the water and the order of PFCs composition was PFOA ＞PFHxA ≧PFBA ≧PFNA ≧PFHpA ＞PFPeA ＞PFOS. However, there were differences for the PFCs composition of the sediment and the order was PFDoDA ＞PFTrDA ＞PFOS ＞PFDA in the southern basin and PFUnDA ＞PFTrDA ＞PFDoDA ＞PFOS in the northern basin. The ratio of short-middle chain carbon (C4 ～C9) PFCs was high and long chain carbon (C12 ～C14) PFCs were not detected in the water of Lake Biwa. However, the ratio of middle-long chain carbon (C10 ～C13) PFCS and PFOS was high and short-middle chain carbon (C4 ～C7) PFCs were not detected in the sediment of Lake Biwa.

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We measured 13 perfluorinated compounds (PFCs) in the groundwater in Tokyo. PFCs with nine carbons or fewer were frequently detected. PFOS and PFOA were detected at high concentrations, despite discharge reduction measures taken since 2010. Chromatograms of PFOS showed variations in the peak area ratio between linear-PFOS and branched-PFOS with the sampling points. To investigate the cause, leaching experiments were conducted for the 13 PFCs and branched-PFOS isomers. The results show that branched-PFOS penetrated the soil faster than linear-PFOS, and shorter chain PFCs faster than longer-chain PFCs. Long chain PFCs with more than 10 carbons were expected to remain in soil.

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House dust has been considered major source of lead for the Japanese. In this study isotope ratios of lead (²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb) were used for the apportionment of lead in house dust. ²⁰⁷Pb/²⁰⁶Pb and ²⁰⁸Pb/²⁰⁶Pb in house dust (＜250µm fraction of vacuum cleaner dust), soil (＜250 µm fraction of garden soil), and outdoor dust (exterior windowsill dust), sampled from 20 detached housings in Japan, were measured by ICP mass spectrometry after HNO₃/HClO₄/HF decomposition. Correlation of ²⁰⁷Pb/²⁰⁶Pb between house dust and outdoor dust was significant (r＝0.539, p＝0.023) while that between house dust and soil was not (r＝0.275, p＞0.05) indicating that a part of lead in house dust of residences of general Japanese was due to infiltration of outdoor dust. However, the correlation was rather weak (R²＝0.29) suggesting that exterior factors contribute less than interior factor(s). Identification of other factors than outdoor dust infiltration would be necessary for the reduction of levels of lead exposure via house dust ingestion.

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Currently, many kinds of pesticides in drinking water have listed up in water quality management of Japan, but some pesticides among these compounds were not clear for their analytical procedures. This paper describes the analytical methods for targeted pesticides in aqueous samples, based on their physiochemical properties such as octanol/water partition coefficients (log Pow) and chemical forms at different pH values (pK_a and pK_b) in water. These values could be employed in liquid-liquid extraction and solid-phase extraction of targeted pesticides from water samples to eliminate contaminants and to extract the compounds. The use of gas chromatography/mass spectrometry (GC/MS, GC/MS/MS), liquid chromatography/mass spectrometry (LC/MS, LC/MS/MS) are more elevated accuracy and selectivity during pesticide analysis in water layers.

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