Survey of toxicity in ambient waters of the Hudson/Raritan Estuary, USA: Importance of small-scale variations

This study was part of a characterization of the nature and severity of wat er-quality problems in the Hudson/Raritan Estuary in New York Stale and New Jersey, USA. The toxicity of ambient water was measured at 51 stations in the estuary by using standard tests with the sea urchin Arbacia punctulata and the marine red alga Clampia parvula. Toxicity identification evaluation s on samples from two stations suggested that cationic metals were the sour ce of the observed toxicity. Overall results showed that toxicity could var y as much on the small scale, i.e., with depth and tide at a single site, a s over several stations within a given subarea of the estuary. Thus, knowin g about small-scale variations in toxicity is essential to understanding th e significance of the variations from different areas or different sampling events.