Studies on Metals in Air Pollution. IV. Studies on the Air-pollutional Nickel

Abstract

Seasonal and geographic variation of nickel concentrations in airborne particulates and deposits were surveyed in Kei-yo industrial zone (Chiba prefecture). The deposits were collected by using deposit gauges at eight sampling points located in the zone from february, 1967 to october, 1968, and airborne particulates were collected by low-volume air samplers at two points from october, 1971 to january, 1973. Samples were ashed in an electric furnace at 500° for 1 hr, and nickel was determined by colorimetry with dimethylglyoxime after two extractions with 20 ml of (1+1) HCl and 1-2 ml of 30% H₂O₂. Maximum amount of nickel (2.81×10^-3 ton/km²/month) was found in the deposit obtained at sampling point III in Chiba City and among the airborne particulates, maximum of nickel (0.059μg/m³) was observed at sampling point V in Ichihara City. The results of seasonal and geographic variation of the concentrations of nickel and the relationship between nickel and other metals in deposits and airborne particulates suggested that main emission source of the air-polluting nickel in Chiba City was an iron work, and in Ichihara City, industries using crude oil.