You are here: Home › Stressors › Pollution › Assessment Studies › Magnitude and Extent of Sediment Toxicity in the Hudson-Raritan Estuary
Magnitude and Extent of Sediment Toxicity in the Hudson-Raritan Estuary
Download the ReportA survey of sediment toxicity was performed in the Hudson-Raritan Estuary to determine spatial patterns, severity, and the relationships among measures of toxicity and chemical substances.
In 1991, 117 samples were collected throughout the estuary (Phase 1).
In 1993, 57 samples were collected in Newark Bay and vicinity (Phase 2). Three toxicity tests were performed under controlled laboratory conditions:
- A 10-day, acute survival test of solid-phase sediments with the amphipod Ampelisca abdita;
- A 48-hour liquid phase test of elutriates with bivalve Mulinia lateralis embryos to determine percent survival and normal embryological development; and
- A 15-minute microbial bioluminescence test (Microtox™) of organic solvent extracts. Concentrations of trace elements, polynuclear aromatic hydrocarbons (PAHs), chlorinated pesticides and other hydrocarbons were also determined.
Overall, 69.2% of the Phase 1 samples were toxic for at least one of the test end-points and 84.2% of the Phase 2 samples were significantly toxic in the amphipod tests. Toxicity was most severe in the East River and diminished eastward and southward. Toxicity was also relatively high in Newark Bay, Arthur Kill, and western Raritan Bay and diminished toward the mouth of the estuary.
Samples with relatively high sand content had relatively low toxicity. The spatial extent of toxicity was estimated for each test. All four test end-points together indicated 5.7% of the area was toxic for Phase 1. During Phase 2, 85.0% of the area was toxic relative to the amphipod test controls.
The causes of the toxicity were not determined. However in Phase 1, diminished amphipod and microbial bioluminescence survivals were significantly correlated with increased PAH concentrations. This strong relationship was influenced by contaminated samples from the upper East River. To a lesser degree, the concentrations of some trace elements and chlorinated pesticides were correlated with microbial bioluminescence inhibition.
In Phase 2, diminished amphipod survival was highly correlated with increasing PCBs, pesticides, and dioxins, but not correlated with PAH concentrations. Amphipod survival decreased with increasing concentrations of lead, mercury, and zinc.