Mercury (Hg) is a globally distributed and highly toxic pollutant in the environment. Its mobility and biomagnification in aquatic food chains depend on its biogeochemistry and redox cycling. Hg isotope analysis is an important new tool for identifying Hg source and tracking Hg transformations in the environment. This review summarizes the following 4 points to endorse the Hg isotope research; 1) definition of Hg delta (δ) values and Hg standards, 2) methods of Hg isotopic measurement, 3) Hg isotopic fractionation, and 4) natural Hg isotope variation.

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Roadside soils and deposited dusts were collected along the roadways between Kamikochi, Chubu-Sangaku National Park and the central area of Matsumoto City, Nagano Prefecture. Their redox potential (Eh), pH (KCl), cation exchange capacity (CEC) and organic carbon content were measured. As a result, regional and seasonal fluctuations were recognized in pH (KCl) and regional variation was observed in Eh. The regional pH (KCl) fluctuation can be considered to have an association with anthropogenic influences. It was suggested that pH (KCl) is the most fundamental factor of chemical condition in the soils and deposited dusts along roadways, from the interrelationships among pH (KCl), Eh, CEC and organic carbon content. Chemical condition is one of the key factors that controls harmful element behavior and involves in the pollution state. This study indicates a potential of mutually complementary manner in roadside pollution mechanism that both contamination substance emission and soil condition change bring an anthropogenic modification of the environment.

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Environmental risk management is important concept for taking better countermeasures, in particular the estimation of sources and mass abundances are requisite to reduce the risk from persistent organic pollutants (POPs) in the environment and make administrative services more efficient. POPs such as the Dioxins is toxic, resist degradation, bio-accumulate and “Stockholm convention on persistent organic pollutants” was adopted in 2001. The Convention prescribes that each party should implement, for example, measures to reduce or eliminate releases from unintentional production. Therefore the grasp of the present status by dioxins pollutions released from unintentional production in the past is important.
In this study, we conducted a survey on the concentration and congener information of dioxins in samples of paddy soils by three layers, saved samples, rivers, its environmental investigation, and then presumed their sources and mass abundances in Kanagawa prefecture, Japan. The concentration of dioxins was 93 pg-TEQ/g in first layer (0∼15 cm) of paddy soils, 53 pg-TEQ/g in second layer (15∼30 cm), and 3.1 pg-TEQ/g in third layer (30∼45 cm). In order to identify the dioxin source in the first layer of paddy soil, the multiple regression analysis was applied. It was found major two sources: pentachlorophenol (PCP), and chloronitrophen (CNP) amounts to about 90 %. PCP and CNP contained dioxin as impurity and were used extensively as paddy field herbicides in Japan in 1960s ∼ 1970s. The outflow of dioxins from paddy soil was estimated to be 2.97μg-TEQ/10a. Compared with the amount remaining in paddy soils 0.0151 % of dioxins have been flowed out from paddy field at 1 year. The concentration of dioxins from preserved samples showed that its half-lives in paddy soils were calculated to 11∼45 years. Further, dioxins concentrationin Zenba river estimated to be 2.2 pg-TEQ/L in irrigation period, 0.54 pg-TEQ/L in non-irrigation period, and 0.99 pg-TEQ/L in annual average concentration that considered direct influence of paddy field by the irrigation.

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At Mt. Tateyama (Murodo, Altitude; 2,450m) and a summit of Tateyama Mountain Range (Gondola Station, Altitude; 1,180m), 20 volatile organic compounds (VOCs) were determind.
The concentrations of VOCs at each site were as follows; benzene: <0.2μg/m³∼0.58μg/m³ and <0.2μg/m³∼0.55μg/m³, toluene: <0.2μg/m³∼1.14μg/m³ and <0.2μg/m³∼1.21μg/m³, and ethylbenzene: <0.2μg/m³ and <0.2μg/m³∼0.28μg/m³. Oher compounds were below the determination limit value (0.1∼2.5μg/m³).
The influence of East Asia, i.e., China and North Korea, and also the influence of Japan were considered to be the sources of VOCs detected at Tateyama Murodo and Gondola Station.

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The concentrations of indium (In), thallium (Tl) and bismuth (Bi) in rivers and lakes in Hokkaido, Kanto area, Tokai area, Shinetsu area and Kyusyu area of Japan were analyzed by ICP-MS. Five hundreds mL of samples were filtrated with 0.45μm membrane filter. The concentrations of the three elements in the filtrate were shown as soluble In, Tl and Bi. The concentrations of the three elements in the residue on the membrane filter of 0.45μm pore size were shown as filtration residue In, Tl and Bi. The averages and standard deviations (unit:ng/L) of the soluble elements were In 2.3±5.1 (n=195), Tl 8.4±17. 1 (n=195), and Bi 1.2±4.2 (n=159). Those for filtration residues were In 9.3±36. 1 (n=177), Tl 30.0±112.3(n=177), and Bi 31.0±118.7 (n=159), respectively. Although, these samples were collected in various seasons and sampling dates, the average concentration might indicate the representative concentrations of In, Tl and Bi in rivers and lakes in Japan. The results for Japanese samples were compared with the results of foreign countries.

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Aqueous phenol solution with bromide ion was treated with sodium hypochlorite at 20°C under various experimental conditions. Changes in the composition and the concentration of the halogenated products in water were determined by gas chromatographic (GC) and GC-mass spectrometric (GC/MS) analyses of diethyl ether extracts. Phenol was shown to produce a variety of halogenated compounds, including polybrominated/chlorinated phenoxyphenols (PXPPs, Br/Cl-predioxins), having three to five halogen atoms, as byproducts in the chlorine-treated water. Production of these PXPPs is dependent on the number of equivalent chlorine atoms per mole of compound and on the reaction pH. These findings suggest that the chlorinetreatment of water contaminated with phenol and bromide ion leads to the formation of Br/Cl-predioxins, which are precursors of the highly toxic halogenated dibenzo-p-dioxins.

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Hydroxylated PCBs (HO-PCBs) are known to occur as metabolites of PCBs in organisms. It has been reported that certain HO-PCBs are present in human blood, and wildlife such as marine mammals. Previous analytical studies have been performed mainly for higher chlorinated (5Cl<) HO-PCBs, but little is known for lower chlorinated (<4Cl) HO-PCBs. HO-PCBs are complex mixtures of congeners, total number of congeners being 837, has the different toxicity by congeners. The purpose of this study was to develop the analytical methods for lower chlorinated HO-PCBs in addition to higher chlorinated ones together with PCBs, and applied to the determination in blood, liver and gallbladder of great cormorant (Phalacrocorax carbo). HO-PCBs and PCBs were detected in all samples analyzed. It was found that the highest concentration was determined in the gallbladder samples and the second in blood samples. In blood and gallbladder, the concentrations of HO-PCBs were found 1.7 and 2.1 times higher than the concentrations of PCBs, respectively. It is interesting that the composition patterns of HO-PCB congeners are completely different between blood and gallbladder samples. The residue pattern of HO-PCB congeners in great cormorant was also different between blood and gallbladder, probably reflecting metabolic pathway of PCBs and HO-PCBs. One explanation is like that; PCBs are metabolized in liver, and the product HO-PCBs are excreted into bile, the HO-PCB congeners as PCB metabolites being appeared in high concentration in gallbladder. A part of HO-PCBs excreted into bile was reabsorbed in gastrointestinal tract and appears in blood, which has high affinity with blood protein being remaining at higher concentration. Ratios of unidentified HO-PCBs/total HO-PCBs were 54% and 94%, respectively, in blood and gallbladder. It seems to be important to understand the chemical structures and behavior of unidentified congeners in order to evaluate toxicological and environmental meaning for HO-PCBs.

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Concentrations of 25 elements (Al, Ba, Ca, Cd, Co, Cr, Cs, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, S, Sb, Sn, Sr, Ti, U, V, Zn) in house dust samples of households in Tokyo Metropolitan Area and Chugoku district in Japan were measured and the source(s) of their household-to-household variations were analyzed with particular focus on those of Pb variation. Vacuum cleaner dusts were supplied from 2-6 households from each of 8 apartment buildings and one pair of adjacent houses constructed by the same house-maker (total number of samples: 27). House dust samples, prepared by passing the cleaner dust through 250 μm mesh, were acid-digested and element concentrations were determined by ICP emission spectrometry and ICP mass spectrometry. Inter-household variation in elemental concentration, as well as that of elemental ratio to Al calculated to correct for the effect of outdoor soil/dust, was large. Elemental ratio to Al did not differ among the buildings for all of the elements except for Mg, indicating element level in house dust varies more due to “dweller′s factor” than to locality and/or materials for the construction of the buildings. The result of correlation analysis indicated paint and general heavy metal pollution involving Cd, Cu, Ni or Zn of unknown source as source of Pb in house dust, which was consistent with the result of the previous study. Additionally, Pb-Sn correlation indicated solder as another source while no candidate source emerged with regard to highly significant Pb-Mo correlation.

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