Optimization and validation of the methods for the determination of polychlorinated biphenyls in soil

Abstract

Polychlorinated biphenyls (PCBs) are synthetic aromatic compounds produced in large quantities around the world since the 1930s, the synthesis of which was banned in the 1970s. These compounds were widely used, among others, as dielectric fluids in capacitors and transformers, grease and plasticizers. Due to the properties of these compounds, such as resistance to chemical degradation and long half-life (from 3 to 40 years), they constitute persistent environmental pollutants. The highest amounts are found in the soil, but they can also be determined in the air, sediments, water, plants and even living organisms. The aim of the work was to optimize and validate the method for determining PCB congeners 10, 28, 138, 153 and 180 in soil. As part of the method optimization, three extraction reagents and two types of purification sorbents were tested. Validation was performed at two fortification levels to determine the recovery and precision of the method. The optimized and validated method was used to analyze the content of selected PCB congeners in real samples collected from the Podkarpacie region. Based on the conducted research, it was shown that the best reagent for the extraction of PCBs from soil is hexane, and the best sorbent for purification is Florisil. The concentration of PCB 10, 28, 52, 138 and 153 in the analyzed real samples was below the limit of quantification (LOQ<0.005 mg/kg). PCB 180 was determined at a level of 0.007 mg/kg in soil taken from the area next to the railway lines in Głuchów.