Ecosystem Targets and Supporting Indicators

Sediment Quality Index

Reduce the area of impaired sediment in Long Island Sound by 20% by 2035 from 2006 baseline.

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Status and Trends

Meeting this target requires an average reduction in the area of impaired sediment of 0.7 per year from 2006-2035.

The Sediment Quality Index (SQI) from EPA 2015 National Coastal Condition Assessment for Long Island Sound (23 spatially-weighted sampling sites), showed that sediment condition was good at 72% of the sites, fair at 23% of the sites, and poor at 5% of the sites. This compares with the 2010 Assessment for Long Island Sound (22 spatially-weighted sampling sites), which showed that sediment condition at 60% of the sites was good, 15% of the sites fair, and 25% poor.  

As of 2015, the SQI Ecosystem Target, to reduce the area of impaired sediment by 20% from the 2006 baseline, has been met. In 2006, the area of impaired sediment was 47% (37% fair and 10% poor); while in 2015, the area decreased to 28% (23% fair and 5% poor). This is a 40% decrease from the 2006 baseline in which exceeds our 20% reduction target.


The EPA 2015 National Coastal Condition Assessment is currently conducted only every five years.

The current number of sampling locations in Long Island Sound is considered too low for good statistical significance, 50 locations would be required for such significance.

The Long Island Sound Study has very limited management tools to improve sediment quality.

How is This Target Measured?

Sediment quality is measured by the Sediment Quality Index (SQI) of the EPA National Coastal Condition Assessment.  This index is a combination of measurements of both sediment toxicity and sediment contaminants.  The most recent Assessment provides information from 2015.


Sediment quality is important because contaminated sediment can harm organisms that live in the sediment and potentially concentrate the contamination in organisms that consume these sediment-dwelling organisms.


Dr. James Ammerman, Long Island Sound Study
[email protected]

Source of Data

EPA National Coastal Condition Assessment,


  • The technical explanation on how the target was selected is found in Appendix B of the Comprehensive Conservation and Management Plan.
  • The number of stations in Long Island Sound in 2010 was limited (22 sites).

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