Persistent DDE in the Mesopotamian wetlands of southern Iraq.

Screening of potential pollutants in surface sediments revealed that almost all persistent organochlorine pesticides were not detected in the newly flooded Mesopotamian wetlands of southern Iraq. This observation suggests that there has been minimal input of organochlorine pesticides recently except for p,p'-DDE which was the only pesticide residue detected (0.29-2.33 microg/kg). It was found in all samples indicating its ability to persist under severe drying of previously exposed surface sediments, high temperature, and intensive solar radiation. p,p'-DDE appears to have a negative relationship with wetland biota, such as zooplankton.