Polycyclic aromatic hydrocarbons in Washington coastal sediments: an evaluation of atmospheric and riverine routes of introduction

Abstract

Polycyclic aromatic hydrocarbon (PAH) compositions were characterized monthly over a 1-year period in atmospheric particulate material (APM) collected from three locations in western Washington state and riverine suspended particulate material (SPM) collected near the mouth of the Columbia River. PAH mixtures of APM are dominated by compounds of combustion origin, with minor levels of the resin acid-derived PAH retene often present. SPM contained comparable levels of individual combustion PAH, retene, and perylene. Atmospheric and riverine contributions of individual combustion PAH to the Washington coastal environment were estimated from these data and other available information. Comparison of estimates with respective PAH accumulation rates measured in lead-210 dated coastal sediments shows that >30% of all combustion PAH, retene, and perylene in these sediments is supplied by SPM discharge from the Columbia River and direct atmospheric input accounts for at most 10% of the combustion PAH. Atmospherically transportable PAH are removed from the air over land to soils and freshwaters within the river drainage basin, eroded on particles, and discharged into the Washington coastal environment along with other nonatmospherically transportable PAH such as perylene as intrinsic constituents of the Columbia River's suspended sediment load.