Atmospheric deposition of PAHs, PCBs, and organochlorine pesticides to Corpus Christi Bay, Texas

Abstract

Air and rain samples were collected at an atmospheric sampling site on Corpus Christi Bay from 20 August 1998 to 16 September 1999. Water samples were periodically collected from Corpus Christi Bay concurrently with air samples for calculation of the air–water gas exchange. Wet deposition, dry deposition and air–water gas exchange rates of polycyclic aromatic hydrocarbons (PAHs) to Corpus Christi Bay were estimated as 182, 68, and −38.4 μg m −2 yr − 1 (negative values indicate loss from surface water to the air), and those of polychlorinated biphenyls (PCBs) were estimated as 3.93, 0.98, and −67.2 μg m −2 yr − 1. Total input of PAHs and PCBs directly to the surface of Corpus Christi Bay were estimated to be 298 and −87.9 kg yr −1, respectively. The estimation indicates that Corpus Christi Bay is currently acting as a net sink for PAHs and as a net source for PCBs to the atmosphere. Total atmospheric input of PAHs to Corpus Christi Bay is not as large as inputs from land runoff and periodic oil spills. The daily and annual gas exchange fluxes of most pesticides appear to be approaching equilibrium between the atmosphere and bay water (flux in is nearly equal to flux out).