Source apportionment and human health risk assessment of PAHs and PCBs in greenhouse soil systems
Intensive greenhouse farming creates distinct enclosed microclimates that can exacerbate the accumulation of persistent organic pollutants in agricultural soils. The primary objectives of this study were to quantify 16 polycyclic aromatic hydrocarbons (PAHs) and 12 polychlorinated biphenyls (PCBs) in tomato-cultivated greenhouse soils in Antalya, Turkiye, to apportion their emission sources, and to explicitly evaluate the influence of greenhouse cover materials (glass vs polyethylene plastic) and seasonal variations on pollutant dynamics. Furthermore, the study aimed to conduct a multi-pathway occupational health risk assessment specifically tailored for greenhouse workers. A total of 100 soil samples were collected across two campaigns (autumn and winter) from 50 greenhouses and 5 reference sites. Following GC/MS quantification, source apportionment was performed using EPA PMF 5.0, and human health risks were estimated via United States Environmental Protection Agency deterministic models. Results indicated that total PAH concentrations were generally higher in glass greenhouses due to limited UV-driven photodegradation, whereas PCB levels showed stronger inter-compound correlations under plastic covers governed by distinct ventilation practices. Positive matrix factorization modeling identified five PAH sources, dominated by diesel combustion (33%), and three PCB sources, primarily driven by atmospheric transport and commercial mixtures (60%). Occupational health assessments revealed that the incremental lifetime cancer risk for PAHs (6.45 × 10−5) and the non-carcinogenic Hazard Index for PCBs (1.30 × 10−3) remained within acceptable regulatory safety limits. However, dermal contact emerged as the overwhelmingly dominant exposure pathway (accounting for ∼75% of the total risk), highlighting the critical need for targeted occupational hygiene practices in enclosed agricultural environments.