Stonington - As thick fog hung over Wequetequock Cove Thursday morning, Richard Chamberlain and his 17-year-old daughter, Katherine, reached over the side of their Boston Whaler idling in the shallow gray water to fill and quickly cap several small bottles, then place them in a cooler.
The process has been repeated at four spots on the narrow cove by the Chamberlains and other volunteers with the local nonprofit organization CUSH (Clean Up Sound and Harbors) throughout the summer, as well as at sites in Stonington Harbor, the Mystic Harbor-Mystic River areas and Pequotsepos Cove, as a means of understanding and improving the health of local waters. About $11,000 in grants, including one from Connecticut Sea Grant, is funding the work.
"We always do the same sites, so we have this steady, long-term collection of data with the same parameters, so we can track things over time," said Claire Gavin, a retired toxicologist and CUSH member in charge of the water sampling project. "All of the things that we monitor have a reason, but dissolved oxygen is the most critical."
CUSH volunteers began collecting water samples in 2008, taking advantage of the University of Rhode Island's Watershed Watch program that trains citizen scientists how to test for dissolved oxygen, salinity, nitrates, chlorophyll, fecal coliform and other water quality measures, and cull those numbers together into a single Aquatic Health Index. The data are shared with state and local officials as well as regional watershed and environmental organizations. Overall, said Fran Hoffman, president of CUSH, the results are showing where the biggest pollution challenges lie, and can help direct what actions should be taken in response.
"The data we collect provides a basis for thinking about local issues," she said.
To collect the samples, volunteers ply small boats into the offshore waters in the early morning hours, before the dissolved oxygen results can be distorted by too many hours of sunlight. Afterward, they gather at a Cogan family home on Elihu Island, where, thanks to CUSH member and host Sally Cogan, the kitchen counters and the kitchen table are put into temporary service as lab stations. Thursday morning, Mark Sugar, a CUSH volunteer who had filled bottles in Stonington Harbor, carefully measured water from his samples for the tests. Beside him at the table, Katherine Chamberlain, who is heading to Middlebury College in the fall to major in environmental studies, wielded a pipette to ease drops of the titrant sodium thiosulfate into samples from Wequetequock Cove. The sample first turned a cloudy blue and then clear, once enough of the titrant had been added. By measuring the amount of titrant used, Chamberlain would find and record the corresponding level of dissolved oxygen.
Her father, meanwhile, worked on other samples at one end of the counter, while Hoffman did still another set of tests at the other.
Since the monitoring began, a clear picture of the best and worst in terms of water quality has emerged. Samples from the Stonington Harbor sites have consistently been in the range deemed good to excellent, while the Mystic Harbor and Mystic River sites vary widely from excellent to fair or poor. Wequetequock Cove, which is prone to algae blooms in late summer from excessive nutrient levels, is even worse, rating scores as low as 4, or "very poor" on the zero-to-100 Aquatic Health Index scale.
The brackish cove, Gavin noted, suffers from being naturally shallow and having inflow from only two fresh water streams. In addition, the cove is overloaded by more runoff from lawns, roofs, road and septic systems than it can flush out quickly. Another CUSH initiative to convince home and business owners to adopt organic lawn care practices is intended to reduce the amount of nutrient-rich runoff.
"We got 2.6 parts per million for the level of dissolved oxygen at one of the sites in Wequetequock Cove, and that's close to a toxic level," said Gavin, referring to that morning's results.