Selected current‐use and historic‐use pesticides in air and seawater of the Bohai and Yellow Seas, China

Abstract

Consumption of pesticides in China has increased rapidly in recent years; however, occurrence and fate of current-use pesticides (CUPs) in China coastal waters are poorly understood. Globally banned pesticides, so-called historic-use pesticides (HUPs), are still commonly observed in the environment. In this work, air and surface seawater samples taken from the Bohai and Yellow Seas in May 2012 were analyzed for CUPs including trifluralin, quintozene, chlorothalonil, dicofol, chlorpyrifos, and dacthal, as well as HUPs (hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and endosulfan). CUP profile in both air and seawater samples generally reflected their consumption patterns in China. HUPs in the air and seawater samples were in comparable levels as those of CUPs with high concentrations. α-Endosulfan, dicofol, and chlorothalonil showed strong net deposition likely resulting from their intensive use in recent years, while CUPs with low consumption amount (quintozene and dacthal) were close to equilibrium at most samplings sites. Another CUP with high usage amout (i.e., chlorpyrifos) underwent volatilization possibly due to its longer half-life in seawater than that in air. α-HCH and γ-HCH were close to equilibrium in the Bohai Sea, but mainly underwent net deposition in the Yellow Sea. The net deposition of α-HCH could be attributed to polluted air pulses from the East China identified by air mass back trajectories. β-HCH showed net volatilization in the Bohai Sea, which was driven by its relative enrichment in seawater. HCB either slightly favored net volatilization or was close to equilibrium in the Bohai and Yellow Seas.