Hi Bronwen,
The EPA took a lot of water quality sampling data for the Gowanus, which is available at:
see this appendix for water data
The NYC Dept of Environmental Protection has a Harbor Water Quality Survey which includes three sampling points in the Gowanus
I am attaching the Gowanus Canal Water Sampling report done in 2011 by National Grid, one of the parties responsible for cleaning up the Canal pollutants, which also includes methadone and estrogen readings, contaminants not covered in the EPA or NYCDEP datasets.
The New York City Water Trail Association posts the Citizen water sampling for enterococcus (sewer contamination) is here:
For things living in Gowanus water you can have a look at this invertebrate sampling report:
Generally I wouldn't bother trying to make the Gowanus Canal water drinkable: it's brackish (or salty) and even though a
water desalination plant is being planned for the Hudson River, the main opportunities for drinking water studies are the old fresh water streams that used to feed the salt marsh. You would need to test these at the outflow points before they mix with the salt water.
These outflows are located at the end of Degraw Street, the First Street landfill basin and the Fourth Street Basin (2 sites, one underneath the 3rd Ave Bridge, and one at Dykes Lumber parking lot). Historically these spring and watershed fed streams provided the potable water supply for early settlers farm houses.
If you are looking for a water profiling exercise, you can look at contaminants coming out of those piped streams, and what would need to be done to get them drinkable, if possible.
NYCDEP did some similar work trying to see if there was any possibility of developing a backup drinking water supply in South Brooklyn (the
Ridgewood system) but found groundwater to be too contaminated.
Let me know if you need more information on potential water sampling locations and I would be happy to help with mapping of the best testing sites.
Best
Eymund
PS. am attaching a picture of Staat's Brook in the Fourth Street Basin that was photographed this weekend during the installation of
Harvest Dome, an art project meant to help spark further dialogue about city water quality.