Distributions, sources, and ecological risks of DDT-related contaminants in water, suspended particulate matter, and sediments from Haihe Plain, Northern China.

The residual levels of dichlorodiphenyltrichloroethane (DDT) and its metabolites (DDXs, including p,p'-DDT, DDD, and DDE) in water, suspended particulate matter (SPM), and sediments from major rivers, lakes, and reservoirs in Haihe Plain were measured with a gas chromatograph equipped with a (63)Ni microelectron capture detector. In the fall of 2004, the contents of the total DDXs in the water and SPM were 0.29 ± 0.69 ng L(-1) and 423.13 ± 577.85 ng g(-1) dry wt., respectively. In the spring of 2005, the total DDXs were 0.36 ± 0.91 ng L(-1) for water and 35.93 ± 62.65 ng g(-1) dry wt. for SPM. The average concentration of DDXs for sediments was 7.10 ± 7.57 ng g(-1) dry wt. during the two seasons. The Eastern-Hebei-Province Coastland River System was the most polluted, which was mainly attributable to the extensive use of DDT pesticide and dicofol in that system. Recent DDT inputs still occur in some regions, as indicated by DDT/(DDD + DDE) > 1 at 29-36 % of the sites for water and 55-61 % of the sites for SPM. The potential ecological risks of DDT in the water were assessed using a species sensitivity distribution model. Only shrimp and crabs were found to have potentially affected fraction values of 1.63 × 10(-3) to 2.27 × 10(-4), with probabilities beyond the hazardous concentration for 5 % of species (HC5) values of 1.90-2.56 %, suggesting only slight risks. DDXs in the sediments of some sites were also of potential risk to benthic organism based on consensus-based sediment quality guidelines.