Temporal change in PCDD/F and PCB levels in the serum of the general population following the start-up of an energy recovery plant in northern Spain

The study assessed temporal trends and spatial variation in serum concentrations of PCDD/Fs and dl-PCBs in the general population before and after the commissioning of an energy recovery plant (ERP) in northern Spain (2017-2023). A longitudinal observational design included 154 adults living either near the ERP or in a control area. Serum concentrations of PCDD/Fs and dl-PCBs were measured in the same participants and compared within them at two time points (before and after the ERP began operations). Linear mixed models were applied to evaluate the effects of study period and area of residence, adjusting for sociodemographic, anthropometric, lifestyle, and dietary variables. Among them, 54.5% resided in the vicinity of the ERP, 53.2% reported not consuming alcohol, 11% were non-smokers, and 40% reported consuming locally produced food. The mean serum concentration of PCDD/Fs + dl-PCB in TEQ-WHO2005, over the entire study period was 10.04 pg TEQ/g lipids. Slightly higher concentrations were observed in the post-startup phase (11.47 pg/g lipids), compared with the pre-startup period (10.56 pg/g lipids), although this difference was not statistically significant. Mixed models indicated higher PCDD/Fs + dl-PCB concentrations among residents of the exposed area in both periods. Men exhibited higher dl-PCB concentrations than women. Consumption of locally produced food was associated with higher PCDD/F concentrations. Although spatial differences suggest greater exposure near the ERP, no evidence indicates that its commissioning increased serum PCDD/F or dl-PCB levels. The levels observed are comparable to those recorded in other developed countries.