The distribution of 4-nonylphenol in marine organisms of North American Pacific Coast estuaries

Abstract

One of the chemical breakdown products of nonylphenol ethoxylates, 4-nonylphenol (4-NP), accumulates in organisms and is of concern as an environmental pollutant due to its endocrine disrupting effects. We measured 4-NP levels in the seawater, sediment, and twelve organisms within the California estuary, Morro Bay, and examined biomagnification of 4-NP using stable isotope abundances (δ15N and δ13C) to quantify trophic position. 4-NP concentrations in organisms from Morro Bay included 25000±8600ngg−1lw in liver of California sea lion, 14000±5600ngg−1lw in liver of harbor porpoise, 138000±55000ngg−1lw in liver of sea otters, 15700±3600ngg−1lw in liver of seabirds, 36100±6100ngg−1lw in arrow goby fish, 62800±28400ngg−1lw in oysters, and 12700±1300ngg−1lw in mussels. 4-NP levels generally showed a pattern of trophic dilution among organisms in Morro Bay, with exceptions of biomagnification observed between three trophic links: mussel to sea otter (BMF 10.9), oyster to sea otter (BMF 2.2), and arrow goby to staghorn sculpin (BMF 2.7). Our examination of other west coast estuaries of USA and Canada revealed that mean 4-NP concentrations in gobies and mussels from Morro Bay were significantly higher than those from a more urbanized estuary, San Francisco Bay (goby: 11100±3800ngg−1lw) and from a remote estuary, Bamfield Inlet, Canada (goby: 9000±900ngg−1lw, mussel: 6100±700ngg−1lw). Relative to other estuaries worldwide, 4-NP levels in seawater (0.42±0.16μgL−1) and sediment (53±14ngg−1dw) of Morro Bay are low, but gobies and oysters have higher 4-NP levels than comparable fauna.