note: nd means below the lower limit of detection; the unit of petroleum hydrocarbons is mg·kg-1.由图2可知...stands for area of coal-fired storage; oa stands for office area; la stands for living area; a~e layer mean
图 3 美国国家优先名录污染源治理措施统计 (2012—2014 年)fig. 3 statistics of the pollution source’s treatment measures in...图 2 美国国家优先名录污染源治理措施统计(1982—1991 年)fig. 2 statistics of the pollution source’s treatment measures in us