The Effect of Water and Sewage Treatment on Reducing Residues of Selected Organochlorine Pesticides in Szczecin (Poland)

Water is principally intended for direct consumption and for the production of food and beverages. It is also a valuable raw material in the industry. Despite the use of multi-stage treatment processes, the quality of drinking water may still be a concern in some countries due to the presence of toxic pollutants, often challenging to remove through the conventional treatment process. The presence of even trace amounts of organochlorine pesticides in drinking water is dangerous due to their ability to accumulate in the human body and their effects, especially their capacity for endocrine disruption. The present study aimed to assess the effect of water and sewage treatment on the efficiency of reducing residues of selected organochlorine pesticides in drinking water and treated sewage. It was found that the water treatment process reduced concentrations of these compounds by an average of 80% (46–100%) and that the levels of organochlorine pesticides in the drinking water were no higher than 0.55% the maximum residue limit (MRL). The sewage treatment process led to a reduction in organochlorine pesticide concentration of 37–100%, averaging 85%, and the sums of organochlorine pesticide residues in treated sewage ranged between 0.02 and 14.97 ng/L in annual terms.