Immutable heavy metal pollution before and after change in industrial waste treatment procedure.

This study compared state of pollution around an intermediate treatment plant of industrial wastes before and after the change of its treatment procedure. Bulk atmospheric deposition, surface soil, suspended particulate matter and groundwater were collected after the plant changed main operation to waste crushing and volume reduction. Their heavy metals content were comparatively investigated with the previous results obtained when it was burning wastes. The bulk heavy metals deposition showed a clear distance-related attenuation both in burning and crushing periods, indicating that the plant was the main emissions source in either case. High concentrations of heavy metals in suspended particles, soil, and groundwater during the crushing period indicated their diffusion to water environment over time. The bulk atmospheric heavy metals deposition decreased significantly, 0.20~ 0.49 times for Cu, Zn, Cd and Pb and 0.69~0.94 times for Cr, during the crushing period than burning period. However, change of their enrichment factors was not significant. It may indicate that the pollution state did not change qualitatively in a bulk deposition basis and quantitatively in a depositing particle basis. The results showed that heavy metals deposition is dominated by suspended and precipitated particulate matters that adsorb and transport the metals.

Contributions of apoplasmic cadmium accumulation, antioxidative enzymes and induction of phytochelatins in cadmium tolerance of the cadmium-accumulating cultivar of black oat (Avena strigosa Schreb.).

The contributions of cadmium (Cd) accumulation in cell walls, antioxidative enzymes and induction of phytochelatins (PCs) to Cd tolerance were investigated in two distinctive genotypes of black oat (Avena strigosa Schreb.). One cultivar of black oat 'New oat' accumulated Cd in the leaves at the highest concentration compared to another black oat cultivar 'Soil saver' and other major graminaceous crops. The shoot:root Cd ratio also demonstrated that 'New oat' was the high Cd-accumulating cultivar, whereas 'Soil saver' was the low Cd-accumulating cultivar. Varied levels of Cd exposure demonstrated the strong Cd tolerance of 'New oat'. By contrast, low Cd-accumulating cultivar 'Soil saver' suffered Cd toxicity such as growth defects and increased lipid peroxidation, even though it accumulated less Cd in shoots than 'New oat'. Higher activities of ascorbate peroxidase (EC 1.11.1.11) and superoxide dismutase (EC 1. 15. 1. 1) were observed in the leaves of 'New oat' than in 'Soil saver'. No advantage of 'New oat' in PCs induction was observed in comparison to Cd-sensitive cultivar 'Soil saver', although Cd exposure increased the concentration of total PCs in both cultivars. Higher and increased Cd accumulation in cell wall fraction was observed in shoots of 'New oat'. On the other hand, in 'Soil saver', apoplasmic Cd accumulation showed saturation under higher Cd exposure. Overall, the present results suggest that cell wall Cd accumulation and antioxidative activities function in the tolerance against Cd stress possibly in combination with vacuolar Cd compartmentation.

Subcellular distribution and potential detoxification mechanisms of mercury in the liver of the Javan mongoose (Herpestes javanicus) in Amamioshima Island, Japan.

In a previous study, we showed that Hg accumulated to high levels in the liver of the Javan mongoose (Herpestes javanicus), a terrestrial mammal that lives on Amamioshima Island, Japan. This suggests a sophisticated mechanism of hepatic Hg detoxication. Assay of the subcellular localization of Hg and the expression of protective enzymes provides important clues for elucidating the mechanism of Hg detoxication. In the present study, the concentrations of 11 elements (Mg, Cr, Mn, Fe, Cu, Zn, Se, Rb, Cd, total Hg [T-Hg] and organic Hg [O-Hg], and Pb) were determined in the liver and in five liver subcellular fractions (plasma membrane, mitochondria, nuclei, microsome, and cytosol) of this species. As the T-Hg level increased, T-Hg markedly distributed to the plasma membrane. The T-Hg levels in all subcellular fractions correlated with Se levels. Although the T-Hg level in the microsomal fraction was relatively low, the ratio of O-Hg to T-Hg was significantly lower in the microsomes than in the other fractions. Significant positive correlations were found between the level of glutathione-S-transferase-pi, a marker of oxidative stress, and the O-Hg and T-Hg levels, but the correlation was better with O-Hg than with T-Hg. Western blot analysis of thioredoxin reductase 2 (TrxR2), a protein involved in protecting cells from mitochondrial oxidative stress, showed that the level of TrxR2 correlated with that of T-Hg. High TrxR2 levels may be one mechanism by which the Javan mongoose attenuates the toxicity of the high Hg levels present in the liver.

Accumulation of trace elements used in semiconductor industry in Formosan squirrel, as a bio-indicator of their exposure, living in Taiwan.

Concentrations of 17 trace elements were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS) in Formosan squirrels (Callosciurus erythraeus) of Taiwan and Japan to document trace element pollution in Taiwan. High concentrations of elements used to produce semiconductors - Ga, As, Cd, In and Tl - were found in animals captured in Miaoli County, which is the nearest site to Hsinchu City, a chief city of Taiwan's semiconductor industry. Significant correlations between Ga, As, In and Tl were found in the kidney, liver, lung and muscle tissues of Taiwanese squirrels. Hierarchical cluster analysis indicated that Ga, As, In and Tl were of the same clade, indicating that Ga, As, In and Tl were discharged from an identical origin. Molar ratios of Ga/As concentration in lungs of animals captured in Miaoli resembled those of animals after intratracheal administration of particulate gallium arsenide (GaAs). This result might indicate that the higher concentrations of Ga and As in the specimens in Miaoli resulted from atmospheric exposure to GaAs.

Trace element accumulations in 13 avian species collected from the Kanto area, Japan.

In the present study, concentrations of 13 elements (Li, Cr, Mn, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Hg) were measured in the tissues of the livers, the kidneys, pectoral muscles, lungs and brains of 13 avian species collected from the Kanto area of Japan. The difference in hepatic heavy metal levels of the grey herons from the two sites was compared. Metal levels in the sediment of the Tama River estuary, situated in the Haneda area, were also measured. These results revealed that heavy metal pollution is present in an aquatic area of Haneda. The accumulation patterns of Cu and Zn in the livers of grey herons appeared to be separated into two groups. Additionally, the present study includes the properties of other metal accumulations and their relationships in avian species.

Characteristics of cadmium accumulation and tolerance in novel Cd-accumulating crops, Avena strigosa and Crotalaria juncea.

Characteristics of accumulation and tolerance of cadmium (Cd) in green manure crops were investigated to identify Cd-accumulating crops and to clarify the mechanisms involved in Cd accumulation and tolerance. Seedlings of eight crop species were treated with Cd (1 mg l(-1) or 5 mg l(-1)) in the growing medium for 4 d. Cd concentration in leaves of Avena strigosa Schreb. cv. New-oat, Crotalaria juncea L. and Tagetes erecta L. cv. African-tall was greater than values used to define Cd-hyperaccumulation (>100 mg Cd kg(-1) DW). However, in leaves of T. erecta, lipid peroxidation level increased significantly, and the activities of superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase were depressed by both Cd treatments. By contrast, A. strigosa and C. juncea exhibited high Cd tolerance. Avena strigosa leaves showed higher activities of antioxidative enzymes such as superoxide dismutase and ascorbate peroxidase than those of other species tested. Crotalaria juncea showed higher amounts of total soluble phenolics which, in leaves, were doubled by 5 mg l(-1) Cd treatment. When two Cd-tolerant accumulators (A. strigosa and C. juncea) and the non-accumulator (C. spectabilis) were treated with lower Cd concentrations for 4 weeks, A. strigosa and C. juncea exhibited superior Cd accumulation in the shoots with greater biomass production compared with C. spectabilis. These results indicate that A. strigosa and C. juncea possess the greater potential for Cd accumulation and tolerance than common crops.

Accumulation of Hg and other heavy metals in the Javan mongoose (Herpestes javanicus) captured on Amamioshima Island, Japan.

Concentrations of 22 elements (Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, total Hg (T-Hg), Pb) and organic Hg (O-Hg) were examined in the liver, kidney and brain of the Javan mongoose (Herpestes javanicus) and in liver of the Amami rabbit (Pentalagus furnessi) from Amamioshima Island in Japan. Relatively high levels of T-Hg levels (from 1.75 to 55.5 microg g-1 wet wt.) were found in the Javan mongoose. As for a comparison of hepatic T-Hg concentrations between the two areas, there was no significant difference between the Javan mongoose in Amamioshima and those in the Okinawa islands. In addition, T-Hg levels in the livers of the Amami rabbit were the same as in the livers of other herbivorous mammals. Taken together, it suggested that T-Hg accumulation in the livers of the Javan mongoose was not affected by the environment but by a specific physiological mechanism. The comparison of Hg and other heavy metal accumulations between terrestrial mammals (13 species, 61 individuals) including the Javan mongoose and marine mammals (18 species, 508 individuals) were also discussed.

Trace elements accumulation and their variations with growth, sex and habitat: effects on Formosan squirrel (Callosciurus erythraeus).

Formosan squirrels are considered a useful bio-indicator because their habitat exists within that of humans. Therefore, concentrations of 19 trace elements were determined in tissues of this species for assessment of environmental pollution in urban Kamakura and rural Izuohshima. Results of analyses revealed high Cu concentrations in the livers of Formosan squirrels. Moreover, concentrations of some trace elements from automobile exhausts-V, Zn, Cu and As-in the specimens from Kamakura were higher than those from Izuohshima. These results reflect the presence of pollution caused by human activities in Kamakura.