Quantification of brominated flame retardants in soil

Soil quality plays a crucial role for farm animals, particularly those raised under free-range or organic conditions. Substances contaminating soil with a significant impact on food of animal origin are persistent organic pollutants (POPs). Recently, polybrominated diphenyl ethers (PBDEs) were included in this group. Novel brominated flame retardants (nBFRs) may also be included soon because they behave similarly in the environment. The aim of the study was to develop and validate a multicomponent method for determining 10 PBDE congeners and 8 compounds classified as nBFRs in soil.

Three soil samples were taken from potentially contaminated sites and three from theoretically uncontaminated sites. A high-resolution gas chromatography coupled with high-resolution mass spectrometry method was adapted.

The method demonstrated high sensitivity, precision and repeatability. The validated procedure enables quantification of $\sum \text{PBDEs}$ in the range of 0.16-1700 ng·g^-1 dry weight (d.w.) and $\sum \text{nBFRs}$ in the range of 0.072-1130 ng·g^-1 d.w. The optimised extraction and clean-up steps addressed the physicochemical diversity of the analytes and ensured reliable separation from co-contaminants. The levels of PBDEs in contaminated samples ranged from 0.23 to 485.7 ng·g^-1 d.w., while nBFRs were detected at significantly lower levels (0.11-0.81 ng·g^-1 d.w.).

Given the absence of regulatory limits for BFRs in food and feed, and their documented presence in agricultural products, the developed method provides a valuable tool for environmental monitoring and risk assessment related to soil contamination and its potential impact on food safety.