Is DDT only found in soils and sediments near Montrose?
No. DDT can be found in soil at low levels in southern Los Angeles County because DDT was widely used in the past. EPA took more than 70 samples of surface soil in residential areas two or more miles away and upwind from the former Montrose plant. The sampling showed that it is common to find 1-3 ppm and as much as 8-10 parts per million (ppm – a measure of how much DDT is in soil) even in soil not close to Montrose. These are very low levels of DDT that do not pose a health concern. This is called background DDT. EPA’s investigations — in residential areas especially — has been checking to see where there might be DDT from the former Montrose plant at levels higher than the background DDT. EPA also has evaluated whether such higher levels in soils might pose a health risk. What levels of DDT are a problem? To cause harm to people, DDT generally must be swallowed, or dust with DDT must be breathed in, trapped on the mucosa and then swallowed. DDT in soil is not readily absorbed into
