METADATA

There are two data files that will be discussed: 
1. The surface sediment concentration data file
2. The change in concentration data file

DATA SOURCE: 
Paleomagnetics and Environmental Geochemistry Laboratory, University of Rhode Island, Graduate School of Oceanography

CONTACT: 
John King, Kathryn Ford

CONTACT ADDRESS:
South Ferry Rd. Narragansett, RI 02882

CONTACT PHONE:
(401) 874-6182

CONTACT EMAIL:
jking@gso.uri.edu; kford@gso.uri.edu

FIELDS:
Shape		Type of symbol
Site_id		Site name used to identify image map polygons for website
Site		Official site number
Name		Official site name
Easting		Location, RI state plane feet
Northing	Location, RI state plane feet
Mo/yr collected	Month and year sediment sample was collected
Ag (ug/g)	Data currently unavailable
Al (ug/g)	Data currently unavailable
As (ug/g)	Data currently unavailable
Cd (ug/g)	Data currently unavailable
Cr (ug/g)	Data currently unavailable
Cu (ug/g)	Copper concentrations in micrograms per gram dry weight
Fe (ug/g)	Data currently unavailable
Hg (ug/g)	Mercury concentrations in micrograms per gram dry weight
Mn (ug/g)	Data currently unavailable
Ni (ug/g)	Data currently unavailable 
Pb (ug/g)	Lead concentrations in micrograms per gram dry weight
Zn (ug/g)	Data currently unavailable
% sand		% of sediment sample >63 microns
% silt		% of sediment sample 3.9-63 microns
% clay		% of sediment sample <3.9 microns
% total carbon	% of sediment sample that is carbon; for Ninigret, Quonochontaug, and Winnapaug the value represents organic carbon, not total carbon

METHODS:
For full description of methods, and how this data was generated, please see the "tech info" section of the website.

LOCATION INFORMATION:
Narragansett Bay Project, 1988	Loran-C
Narragansett Bay Project, 1998	Sites located with Trimble NT 200D GPS, not differential corrected.
Salt Ponds Project, 1999	Sites located with Trimble NT 200D GPS, not differential corrected.

SURFACE SEDIMENT CONCENTRATION DATA NOTES:
Some site names are listed as "Old Station X."  This refers to the original site name in the Narragansett Bay Project, 1989.  The sites were renamed in the Narragansett Bay Project, 1998.
Some values are missing.  These sites were not measured for metals due to high sand content.

SEDIMENT QUALITY CRITERIA:
Long, et al (1995) took a large database of sediment toxicity tests and screened it for samples labeled as toxic by the original investigators. The lower 10th percentile of these concentrations is the ER-L.
The ER-M is the median concentration of the same database screened for samples labeled as toxic by the original investigators. 
Concentrations below the ER-L are within the defined "no effects range," concentrations between the ER-L and ER-M are within the defined "possible effects range," and concentrations above the ER-M are defined as the "probable effects range."
From Long, et al 1995, Environmental Management, Vol 19: 81-97 (NOAA)
ERL and ERM are also described in the tech info section of the website.

CHANGE IN CONCENTRATION DATA NOTES:
The values listed were calculated by subtracting the concentration measured in 1989 from the concentration measured in 1998.
Positive values indicate an increase in concentration.
Negative values indicate a decrease in concentration.
Small changes should be interpreted with caution.

WEBSITE NOTES:
The background map was kindly provided by Paul Jordan, RIDEM, with the help of Tom Ardito, Narragansett Bay Journal.
Much of the website coding was created by Roland Duhaime, Dept. of Natural Resources, University of Rhode Island.