Benzo[a]pyrene and Phenanthrene in Municipal Sludge from the Yangtze River Delta, China

To evaluate the contaminated conditions of benzo[alpyrene （B[a]P） and phenanthrene （PA） in sludge and to ascertain whether B[a]P limit for land application of sludge exists, the contents of B[a]P and PA in 46 sludge samples from 15 cities in the Yangtze River Delta area of China were determined using high performance liquid chromatography （HPLC） coupled with a fluorescence detector after ultrasonic extraction and silica gel cleanup. B[a]P contents ranged from non-detectable to 1.693 mg kg^-1 dry weight （DW）, averaged 0.402 mg kg^-1 DW, and were 〈 1.0 mg kg^-1 DW in most of the sludge samples. PA was found in all the sludge samples analyzed; its contents ranged between 0.028 and 1.355 mg kg^-1 DW, with an average value of 0.298 mg kg^-1 DW. Most of the sludge samples contained 〈 0.5 mg kg^-1 DW PA. All 46 municipal sludge samples analyzed in this study showed B[a]P contents 〈 3.0 mg kg^-1 DW, which is the limit value for sludge applied to agricultural lands in China. The contents and distributions of B[a]P and PA in municipal sludge were related to sludge types, sources and treatment technologies, along with the physical and chemical properties of these pollutants.