Publication Summary

A screening level survey of sediment quality in inner Shelton Harbor was conducted in May 1999. The primary objectives of this investigation were to (1) evaluate contaminant levels (metals and organics) near potential sources and (2) estimate the distribution of wood waste in subtidal sediments.

Ten nearshore stations were sampled for chemical screening analysis. An additional 37 subtidal stations were sampled to evaluate and quantify the distribution of wood debris. Field observations, digital photos, and towed underwater video were used to qualitatively assess the distribution of wood in the inner harbor.

A screening level survey of sediment quality in inner Shelton Harbor was conducted in May 1999. The primary objectives of this investigation were to (1) evaluate contaminant levels (metals and organics) near potential sources and (2) estimate the distribution of wood waste in subtidal sediments.

Ten nearshore stations were sampled for chemical screening analysis. An additional 37 subtidal stations were sampled to evaluate and quantify the distribution of wood debris. Field observations, digital photos, and towed underwater video were used to qualitatively assess the distribution of wood in the inner harbor.

Concentrations of both metals and organics were relatively low at the nearshore sites evaluated for chemical contamination. Most of the contamination appears to be associated with specific sources. Nineteen violations of the sediment quality standards (marine criteria) were noted. Tributyltin concentrations at two locations exceeded the Puget Sound Dredge Disposal Analysis/ Sediment Management Standards interim screening level of 73ugTBT/kg. PCBs were low at all sites tested.

The highest wood levels (measured by total volatile solids) were present in the southwest portion of the harbor. Four strata had significantly higher levels of wood than the reference site. Three organic compounds (benzoic acid, phenol, and 4-methylphenol) commonly associated with wood debris were measured at concentrations above the SMS cleanup screening levels in four of the wood characterization areas.

Underwater video indicated a patchy distribution of wood debris, ranging from a clean bottom to bark accumulations that completely covered the sediment surface. The predominant wood debris was bark. Sulfur reducing bacteria mats were abundant on the sediment surface in the inner harbor, indicating anoxic conditions. It is recommended that best management practices be implemented immediately at the Simpson Mill to minimize the loss of wood chips during barge loading operations.

Link to EIM data for User Study ID SHELHARB