In Yangmingshan National Park, located in the northern part of the Taiwan Island, there is a very rare area where fish (Channa asiatica) live in spite of acid environments. The origin of the acid in local acid ponds and rivers and the evolution of the water chemistry are discussed on the basis of sulfur stable isotope ratios and chemical equilibria. One of the sources of the acid is sulfuric acid, which is derived from the oxidation of hydrogen sulfide in volcanic gas gushing out from fumaroles around the area and from acid deposition supplied from Taipei City. It is also derived from the oxidation of pyrite: the sulfur stable isotope ratios of delta 34S of +1@1000 to +4@1000 (relative to CDT) of sulfate in acid pond waters (pH 3-4) could be related to those of hydrogen sulfide in volcanic gas, pyrite in local pond sediments and soils, and sulfate in rain water. One acid source is sulfuric and hydrochloric acids arising in springs from geothermal activity: the delta 34S values were characterised by +13@1000 to +17@1000 sulfate-S, which was provided by a disproportionation reaction of sulfur dioxide in the depths. Another acid source could be the oxidation of iron(II). Under acidic conditions, the water-rock reaction gives rise to high concentrations of aluminium and iron. While flowing down surface streams, iron(II) is oxidised to iron(III) and then hydrolysed to cause further acidification under oxic conditions. The concentrations of iron and aluminium are controlled by redox and dissolution equilibria.

The diethyl ether extracts from aqueous 4-methylphenol solutions in the presence of bromide ion after treatment with chlorine were mutagenic to the Ames salmonella test strain TA100 in the absence of rat liver homogenate. Gas chromatography/mass spectrometry (GC/MS) showed the occurrence of halogenated products in the extracts: bromo-4methylphenols, bromo-4-methylquinones and brominated 4-methylphenol dimers. The diethyl ether extracts were fractionated into several fractions by polyamide thin-layer chromatography (TLC). The fractionated components were examined for mutagenicity by means of Ames assays, and were identified by GC/MS. TLC fraction of the extracts revealed that two components present in the extracts are mutagenic. GC/MS analysis indicated the presence of 2,6-dibromo-4-hydroxy-4-methylcyclohexa-2,5-lien-1-one (2,6-dibromotolquinol) as the major mutagen and brominated 4-methylphenol dimers as minor mutagenic compounds in the chlorinated 4-methylphenol solutions containing bromide ion. Production of 2,6-dibromotolquinol in water was found to be dependent on the equivalents of chlorine per mole of compound and the reaction pH.

For the purpose of the investigation of characteristics of VOCs found indoors in recently constructed residential buildings, we measured the behavior of VOCs which were sampled at one-month intervals over a period of one year from the, initial occupancy date in both a detached house and an apartment in a multiple' dwelling. At the first passive sampling from the wooden detached residential building, n-hexane, n-undecane, toluene, ethylacetate, methylethylketone, alpha-pinene and (+)-limonene were present in relatively high concentrations of 10 ppb or higher in the living room. Then these VOCs showed a declining trend with time. p-Dichlorobenzene showed an extremely high concentration (approx. 320 ppb) in June, which subsequently declined with each passing month. There is a high possibility that the cause was the use of a pesticide containing p-dichlorobenzene during the period of changeover from winter to summer clothes in June. On the other hand, from the multiple dwelling, four VOCs showed values of 10 ppb or more (toluene, 1,2,4-trimethylbenzene, methylethylketone and alpha-pinene). Of these VOCs, methylethylketone concentration was in excess of 100 ppb, and then also showed a declining trend with time. Even for new residential buildings completed during the same time frame, it was shown that the types of VOC contaminants and their concentrations varied significantly.

Aluminum in lake water and in the organs of the fish Tribolodon hakonensis was investigated in Lake Usoriko (pH 3.6), Lake Inawashiroko (pH 5.0), and the Tenryu River (pH 7.7). The concentration of total soluble aluminum in the water was 0.51 mg l Ϫ1 in Usoriko, 0.05 mg l Ϫ1 in Inawashiroko, and less than 0.01 mg l Ϫ1 in the Tenryu. The chemical forms of soluble aluminum in the acid water were characterized as Al 3ϩ , AlL 2ϩ , and AlL Ϲ1ϩ . More than 90% of soluble aluminum in the water of Usoriko was Al 3ϩ , whereas AlL 2ϩ was dominant in the water of Inawashiroko. The aluminum concentration in the organs of T. hakonensis in Usoriko was 42 µg g Ϫ1 wet weight in gills, 4.2 µg g Ϫ1 in muscle, 6.9 µg g Ϫ1 in bone, 12.7 µg g Ϫ1 in liver, 6.0 µg g Ϫ1 in kidney, and 6.0 µg g Ϫ1 in intestine, indicating accumulation of aluminum in the gills. The aluminum concentration in the organs of T. hakonensis living in Inawashiroko was approximately the same, in spite of the difference in water chemistry of the two acid lakes, especially for pH and aluminum. This suggests that aluminum accumulation might be controlled in the fish living in the acid lakes. In contrast, the aluminum concentration in the gills of T. hakonensis from the Tenryu was 2 µg g Ϫ1 .