Gas exchange of OCPs across the air–water interface at the creek adjoining Mumbai harbour, India

Abstract

The concentrations of organochlorine pesticides (OCPs) such as hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane (DDT) and its metabolite (DDE) and endosulfans were determined in air and water in order to estimate the magnitude and direction of gas flux across the air-water interface at the creek adjoining Mumbai harbour, India. The range of HCH residues in air was found to be between 1.0 and 22.5 pg m(-3) and that in sea-water was between 1.7 to 34.4 ng l(-1) DDT and its metabolite (DDE) residues in air ranged between 2.1 and 80.8 pg m(-3) and in sea-water between 1.4 to 19.2 ng l(-1). The concentrations of beta-endosulfan in air and sea-water samples were found to be 1.0-1.6 pg m(-3) and 1.0-2.6 ng l(-1) respectively. The HCHs revealed positive values of the fluxes (1.001 microg m(-2) d(-1) for alpha-HCH, 0.107 microg m(-2) d(-1) for beta-HCH and 0.455 microg m(-2) d(-1) for gamma-HCH) indicating the tendency to transfer these contaminants from water to air. This implies that the marine water bodies principally act as a source of HCHs. The fluxes for DDTs (p,p'-DDE and p,p'-DDT) also follow the same pattern as HCHs and show high positive values (1.698 microg m(-2) d(-1) for DDE and 2.422 microg m(-2) d(-1) for DDT). The present study suggests the active transfer of these dissolved OCPs into the atmosphere due to volatilization.

Selected Organochlorine Pesticides and Polychlorinated Biphenyls in Urban Atmosphere of Pakistan: Concentration, Spatial Variation and Sources

“…The fresh use of OCPs in Karachi appeared to be limited, which was supported by the overall lower OCPs concentration (∼half of that observed for Lahore). In recent past, the oceanic waters and marine sediments are found to become secondary sources of POPs due to their volatilisation back to the atmosphere. , A study conducted on coastal sediments in Karachi reported higher residual contamination of pesticides including DDT, HCH, and heptachlor. Karachi receives untreated sewage of millions of residents, industrial effluent, and runoff from agriculture lands through the Lyari and Malir river streams, which finally drains into the Arabian Sea (Figure ). , High temperatures in Karachi throughout the sampling period, ranging between 18 and 32 °C (Table SI-4, Supporting Information) was enough to aid revolatilization of residual POPs.…”

“…In earlier studies, , a higher concentrations of residual DDTs, especially p , p ′-DDE, HCH-isomers, and other pesticides, have been recorded in samples from Arabian seawater and sediments. Pandit et al reported the volatilization of OCPs from the Arabian Sea water to the atmosphere, which may lead to the higher levels of OCPs near south coastal zone of Karachi. In addition, the DDT-containing antifouling paints have been reported to be used on fishing ships for preventing the adhesion of halobios (e.g., barnacles, mollusks, and algae), which could be a potential source of DDTs.…”

Diffusive exchange of PAHs across the air–water interface of the Kaohsiung Harbor lagoon, Taiwan

“…However, in many instances, including the present study, the sum of the diffusive fluxes of Ph and Py could account for over 50% of total PAH flux (Bamford et al, 1999a;Gustafson and Dickhut, 1997;Nelson et al, 1998;Pandit and Sahu, 2001;Tsapakis et al, 2006). Therefore, between-study flux comparisons are useful for these two PAHs.…”

Current status of persistent organic pesticides residues in air, water, and soil, and their possible effect on neighboring countries: A comprehensive review of India

“…This might affect global POP concentration. Pandit and Sahu (2001) also suggested that OCPs are removed rapidly from inland water and agricultural fields, and washed out, in the majority of cases, to the ocean. The concentration of DDTs, HCHs and endosulfans in the air is dependent on concentrations in the surface seawater.…”