Abstract:

Water and surface sediment samples were collected from the Tiaozi River, a branch of Liaohe River, in spring, summer, autumn and winter to determine the contents of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs). On this basis, the distribution and sources of the two organic pollutants were investigated. Results indicate that the total PAHs levels in the water samples were 658.1—3 096.6 ng/L (arithmetic mean: 1 522.1 ng/L) and those in the sediments were 775.7—2 835.4 ng/g (1 374.0 ng/g). α,β,γHexachlorocyclohexanes (HCHs) were detected in all the samples and the total HCHs were 5.36—16.57 ng/L (10.93 ng/L) in the water samples and 2.87—5.56 ng/g (4.34 ng/g) in the sediments. Dichlorodiphenyl trichloroethanes (DDTs) in all the samples were below the detection limit. Temporospatial distributions of PAHs in the river water and sediments were similar: the PAHs levels decreased in the order of winter>autumn>spring>summer and decreased from the upstream to the downstream. In contrast, temporospatial distributions of HCHs in the river water and sediments were opposite: HCHs levels in the water decreased in the order of summer>spring>autumn>winter and reduced from the downstream to the upstream; HCHs levels in the sediments decreased in the order: winter>autumn>spring>summer and decreased from the upstream to the downstream. The results for source identification of PAHs and HCHs reveal that PAHs in the river were mainly from the combustion of coal and transportation, and HCHs were from the past use of lindane.

Key words: Tiaozi River, polycyclic aromatic hydrocarbon (PAHs), organochlorine pesticide (OCPs), temporospatial distribution, source identification