Temporal Variations and Source Identification of Polycyclic Aromatic Hydrocarbons (PAHs) in Rainwater Collected in a Semi-Urban Area within an Industrial Area in Turkey

Abstract

The purpose of this study was to investigate temporal variations and to identify source of polycyclic aromatic hydrocarbons (PAHs) between October 2019 and September 2020 in forty-one rainwater samples collected in a semi-urban area of Gebze, Kocaeli which is highly affected from by industrial pollution due to the existence of many organized industrial zones. Sampling was done for every rainy day during sampling period and the meteorological data (temperature, humidity, wind speed etc.) for sampling days were recorded. The collection of PAHs from the rainwater samples was done by using the SPE C18 cartridge with the help of hexane-acetone mixture (v/v) and gas chromatography system-triple quadrupole mass spectrometry (GC-MS/MS) was used for the measurement of PAHs. The calibration curves of PAHs, which presented greater than 0.995 of r2 values, possessed quite good linearity. Limit of detection (LOD) values for all PAHs were in the range of 0.10 ng/L and 0.29 ng/L, and the ranges of limit of quantification (LOQ) were from 0.32 ng/L to 0.98 ng/L. All PAHs reached their highest concentrations during the cold season, with a significant decrease in the concentrations from the cold months to the hot months with a few exceptions. Monthly mean total PAH concentrations ranged from 135.0 ng/L (in July) to 401.6 ng/L (in January). The compounds with the highest contribution to the total PAH concentration were naphthalene (28.20%), phenanthrene (16.84%), fluoranthene (12.44%), pyrene (9.31%) and benzo(b)fluoranthene (6.17%). The fraction of benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenz(a,h)anthracene, indeno(1,2,3-c,d)pyrene defined by the competent authorities as high carcinogenic effects on humans to the total PAH concentration in rainwater samples were only 16.93%. When the results obtained from the ratios of different PAH compounds in diagnostic analysis (Fluoranthene/Pyrene ratio: 1.31; Fluoranthene/Fluoranthene + Pyrene ratio: 0.58 and Phenantherene/Phenanthrene + Anthracene ratio varied from 0.92 to 0.95) were evaluated together, all these ratios indicated the dominance of coal combustion in the source of PAHs. The results of benz(a)anthracene, benzo(k)fluoranthene, dibenz(a,h)anthracene, fluorene, naphthalene and pyrene were frequently lower than the previous studies in literature.