Sedimentary nonylphenol contamination in an urbanized, industrialized segment of the Delaware River estuary, USA

Nonylphenols (NPs) are primarily used as intermediates in the manufacture of nonylphenol ethoxylates (NPEs), a major group of nonionic surfactants. Worldwide, about 500,000 tons of alkylphenol ethoxylates (which include NPEs) are produced annually for use in detergents, paints, pesticides, textile and petroleum recovery chemicals, metal working fluids, and personal care products (Naylor et al. 1992). Because of their wide spread use, especially in cleaning products and as industrial processing aids, the majority of NPEs are delivered to wastewater treatment plants (WWTPs). During anaerobic sewage digestion, NPEs are biodegraded by the hydrolytic removal of ethoxylate groups forming short-chain ethoxylates, carboxylic acid derivatives and NPs. Subsequently, wastewaters originally containing high concentrations of NPEs may potentially contain elevated concentrations of NPs upon discharge. Additionally, NPs may be formed after NPE-containing waters are discharged directly to receiving waters from run-off and equipment cleaning areas (Hale et al. 2000). Studies reporting environmental levels of NPs are relatively limited, even in heavily urbanized and industrialized areas where concentrations would likely be detectable and potentially high. This is particularly true for the Delaware River estuary which stretches approximately 200 Km from the fall line of the Delaware River just above Trenton, NJ to the mouth of the Delaware Bay between Cape May, NJ and Cape Henlopen, DE. The most industrialized and urbanized segment of the river runs between the cities of Philadelphia, PA and Camden, NJ. In 1978, NP isomers were identified within the water column of the Delaware River with highest levels being centered around Philadelphia (0.04 to 2.00 mu g/L) (Sheldon and Hites 1978). However, since this study, levels of nonylphenols in the water column, particularly those adjacent to the urbanized and industrialized regions of Philadelphia, PA, have not been reported in the literature.