Distribution, sources and ecological risks of polycyclic aromatic hydrocarbons in water-sediment system in Lake Small Baiyangdian

Abstract

The contents of 15 priority polycyclic aromatic hydrocarbons (PAHs) in water, suspended particulate matter (SPM) and sediment from six sampling sites in Lake Small Baiyangdian nearby Duancun Village were measured by GC-MS. The PAHs distribution, composition, source and ecological risk were analyzed. The following results were obtained: (1) the total contents of 15 priority PAHs (PAH15) varied from 40.1 to 74.0ng/L with the average of 51.0ng/L in water, from 2438.0 to 5927.0ng/g with the average of 4528ng/g in SPM, and from 466.9 to 1366.4ng/g with the average of 755.6ng/g in sediments. Compared with other areas in or out of China, the PAHs contamination was not serious. (2) The percentages of 2- and 3-rings PAHs accounted for more than 80% of PAH15 in water, SPM and sediment, respectively. From water, SPM, to sediments, the percentages of 2-rings PAHs were declined sequentially; while these of 3- and 4-rings as well as 5- and 6-rings PAHs were increased gradually. (3) The major sources of PAHs in sediments were the combustions of biomass fuels (straw, firewood) and coal; while the combustions of liquid fossil fuels including gasoline, diesel and crude oil was the secondary sources. (4) Owing to the contents of Fluorene (FLO) and Phenanthrene (PHE) varying between the ERL(effects range low) and ERM (effects range median), their probabilities of ecological risks was estimated between 10%-50%. The probabilities of ecological risks for the rest species of 15 priority PAHs were below 10%, since their contents were lower than the ERL.