Atmospheric deposition of organochlorine pesticides (OCPs): Species, levels, diurnal and seasonal fluctuations, transfer velocities

Abstract

Organochlorine pesticides (OCPs) in the persistent organic pollutants class are pollutants that can enter water reservoirs, soils, and sediments by atmospheric deposition. The aim of the present study was to determine the total atmospheric deposition fluxes of OCPs in a semi-rural area in Bursa, Turkey. Total deposition fluxes, phase distributions, dry deposition velocities and mass transfer coefficients were calculated in the samples collected during day and night periods. Ambient air OCP samples were also taken simultaneously. Samples were analyzed for 9 OCP compounds (alpha-, beta-, and gamma-hexachlorocyclohexane; heptachlor epoxide; endrin; endosulfan beta; endrin aldehyde; and methoxychlor). OCPs were found predominantly in gas and dissolved phases in all seasons for the ambient air and deposition samples, respectively. The annual maximum averages of deposition fluxes for dissolved and particulate phases for the beta-HCH compound were 200.2 ng/m(2)-day and 28.6 ng/m(2)-day, respectively. The average dry deposition velocity and mass transfer coefficient values calculated for OCPs were 4.6 +/- 5.5 cm/s and 0.46 +/- 0.37 cm/s, respectively, and these values were in line with the values in the literature. In the nighttime and daytime samples, the average deposition fluxes of OCP compounds in the dissolved phase were 1.5-10 times higher than those in the particulate phase. Although there were no great differences in daytime and nighttime samples, it was found that the flux values during daytime periods were sometimes higher.