Determination of hydroxy derivatives of PAHs in sewage sludge by GC-MS/MS

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are organic environmental contaminants, many of which pose serious health risks due to their persistence, toxicity and potential carcinogenicity. Their hydroxyl derivatives (OH-PAHs) are increasingly recognised as important contaminants in wastewater treatment systems because they are more water soluble, mobile and bioavailable than their parent PAHs. The aim of this study was to determine the content of common OH-PAHs in stabilised sewage sludge. The sediments were prepared by extraction using the QuEChERS method and analysed by GC-MS/MS technique. The results confirmed the highest levels of 1-naphthol and 2-naphthol in sludge samples collected in summer (78.1 ± 8.2 μg·kg‐1 and 126.9 ± 10.9 μg·kg‐1, respectively) compared to samples collected in winter (68.5 ± 9.3 μg·kg‐1 and 54.7 ± 9.7 μg·kg‐1, respectively). The concentrations of the remaining OH-PAHs were higher in winter than in summer. The highest content of OH-PAHs in summer was 2-naphthol (126.9 ± 10.9 μg·kg‐1) and the lowest was 2-fluorenol (1.17 ± 0.3 μg·kg‐1), and in winter 3-hydroxybenzo(a)pyrene (78.1 ± 7.4 μg·kg‐1) and 2-fluorenol (7.6 ± 0.7 μg·kg‐1). The validation parameters were within acceptable limits. The GC-MS/MS method demonstrated high accuracy and selectivity and can be successfully used for the detection and determination of OH-PAH concentrations in sewage sludge. Monitoring the content of OH-PAHs in wastewater systems provides information on the possible accumulation of these compounds in the environment and can therefore contribute to sustainable sludge management.

Keywords

• OH-PAHs
• sewage sludge
• QuEChERS
• gas chromatography
• mass spectrometry