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Seeking the possibility of the formation of benzoic acids from benzyl halides in natural soil, a model oxidation reaction of
the halides was carried out in the presence of water and soil in an open air
under UV light irradiation. Addition of TiO2 to soil raised the yield of the acid,
implying such a metal oxide plays a real catalytic role in this oxidation. By
these supplementary experiments, one of the possibilities for the formation of
benzoic acids in natural soil from benzyl chlorides was supported.
The present study examined the effects of air pollutants on people’s health, focusing on dust produced from automobile tires while cars drive on roads. The annual volume of dust resulting from tire wear, calculated based on the number of automobiles registered in Japan, was 1747245.4 m3. To put it simply, this translates to approximately 1.4 times the volume of the Tokyo Dome, a famous Japanese baseball stadium. Particulate substances are categorized into three groups depending on their size, and dust resulting from tire wear is classified into the coarse particle mode along with mold spores, pollen, and dust produced from brake pads. This study examined whether or not tire dust causes health damage similarly to pollen, a particulate substance in the same group. There were 38/cm2 dust particles resulting from tire wear on a busy road in Osaka Prefecture, and this number was larger than that of cedar pollen/cm2 (35), a cause of hay fever, identified in Hokkaido. The results suggest that tire dust may also adversely affect the health of people if any of its constituents has a toxicity or causes allergies.
Apple orchard surface soils in Japan are polluted with copper (Cu), lead (Pb), and arsenic (As) due to long-term use of metal-based pesticides. We investigated the effects of heavy metals accumulated in the surface soils in apple orchards on the microbial biomass and the microbial communities. Soil samples were taken from a chestnut orchard (unpolluted control) and five apple orchards with different degrees of heavy metal pollution. Total concentrations of Cu, Pb, and As in soil ranged from 29 to 931 mg/kg, 35 to 771 mg/kg, and 11 to 198 mg/kg, respectively. The amount of microbial biomass carbon expressed on a soil organic carbon basis decreased with increasing concentrations of heavy metals. Thus, the heavy metals that accumulated in apple orchard surface soils had adverse effects on the soil microbial biomass. The analysis of phospholipid fatty acid (PLFA) composition indicated that the microbial community structure had changed because of the pesticide-derived heavy metals in soil. The relative abundance of gram-positive bacterial marker PLFAs increased and that of fungal marker PLFA decreased with increasing concentrations of heavy metals in soil. Denaturing gradient gel electrophoreses targeting the 16S ribosomal RNA gene of bacteria and the 18S ribosomal RNA gene of fungi also showed shifts in the composition of bacterial and fungal communities induced by soil pollution with heavy metals. However, the diversity of microbial communities was not significantly affected by the heavy metal pollution. This was attributable to the adaptation of the microbial communities in apple orchard surface soils to heavy metals derived from previously used pesticides.