Spatial distribution, source identification, ecological risk assessment, and air–seawater/seawater– Sediment exchange rates of polycyclic aromatic hydrocarbons in Pars special economic energy zone, Iran

Abstract

Polycyclic aromatic hydrocarbons (PAHs) have been introduced as major pollutants released by the oil, gas, and petrochemical industries. Against this background, the present study examined the coastal air, seawater, and sediments in the Pars Special Economic Energy Zone (PSEEZ), Iran, in terms of pollution caused by such compounds. Considering the industrial facilities and residential areas in this region, the total suspended particulate (TSP), seawater, and sediments were sampled (n = 10) and then analyzed over the course of two seasons via gas chromatography-mass spectrometry (GC–MS). The total concentrations in the TSP, seawater, and sediments were found to be in the range of 346-739ng_PAH/g_TSP, ND-84.87 µg/L, and ND–306.7 ngg⁻¹(dw), respectively. The positive correlation coefficients between sediment organic matter (OM) and concentrations did not show a significant relationship. Crude oil and its derivatives and biomass-coal combustion were identified as the main sources of pollution. Carcinogenic PAHs (CPAHs) were further detected at much higher concentrations near industrial facilities. Sediment quality guidelines (SQGs) and risk quotients (RQs) showed that coastal seawater and sediments posed acceptable and moderate ecological risks. According to the fugacity diagrams, the seabed and seawater served as secondary sources of pollution. The total concentration and values obtained in earlier investigations were also comparable. Nonetheless, most maximum points could provide a point-form of the pollutant concentration. Therefore, preventive measures are required to ensure the protection of the environment.