To control pest outbreaks, airplanes sprayed more than 6,280 tons of dichlorodiphenyltrichloroethane (DDT) onto forests in New Brunswick, Canada, between 1952 and 1968, according to Environment Canada. By 1970, growing awareness of the harmful effects of DDT on wildlife led to curtailed use of the insecticide in the area. However, researchers have now shown that DDT lingers in sediments from New Brunswick lakes, where it could alter zooplankton communities.