Pesticides in Norwegian Landfill Leachates

Pesticides have been analyzed in 28 grab samples of untreated and 12 samples of treated leachate from eight Norwegian municipal solid waste (MSW) landfills, over a period of 10 years, with the purpose to screen for compounds and to evaluate the removal in different treatment systems. Also 1 grab samples of leachate sediments is included. A total of 12 compounds were detected. The most frequently detected group of compounds are the phenoxy acids, and they also occur in highest concentrations, up to 230 μg/l for mecoprop, in this study. Also three fungicides and one insecticide were detected, but in much lower concentrations. All samples exceeded the maximum limit value (MLV) for the sum concentration of pesticides in drinking water (0.5 μg/l), and six compounds exceeded the environmental toxicity limit (ETL). Reverse osmosis showed good removal of phenoxy acids, while sequential batch reactor aerobic treatment, as well as aerated lagoons in combination with wetlands, groundwater infiltration and reactor treatment showed slightly lower removal.