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Water Quality Monitoring in the St. Croix Watershed

Project History:

  The St. Croix watershed faces unique environmental and economic management challenges as well as an international border. In the past there have been sewage and industry spills within the watershed; infrequent water quality sampling has often left spills undetected, causing increased damage to the environment. The most recent assessment of the watershed prior to this study was completed in 2000. In 2017 the Saint Croix International Waterway Commission (SCIWC) began to monitor water quality throughout the St. Croix watershed. Regular water quality analysis will allow for a timely detection of contaminants, measurable comparisons of historical to current water quality, and will contribute to longstanding data records.

Project Summery:

  The SCIWC selected 25 water quality sample sites from “Future Water Quality in the St Croix Watershed: A proposal for preliminary surface water classification under New Brunswick’s Clean Water Act” prepared by the SCIWC in March of 2000.  These sites were re-sampled during August to November of 2018, and all sample sites were in New Brunswick. Water quality sampling sites in Maine are being monitored by the Sipayik Environmental Department and Indian Township.


  The sampling conducted included testing each predetermined site with a pH meter, conductivity meter, YSI readings for temperature and dissolved oxygen (DO), and the collection of surface water samples for testing at RPC in Fredericton. The water samples were analyzed for surface water chemistry, surface water metals, total suspended solids, and Escherichia coli. Notes were taken for air temperature and visual inspections of each site were also conducted. Notes about the weather, nearby vegetation, algae, pollution sources, insects, and fish were recorded. The presence of any pollen, oil, or foam on the surface of the water was also recorded in the field notes.

  Water samples were collected in sample jars from RPC. The samples were kept in a cooler, then stored in a refrigerator, until they could be shipped to RPC the next morning via courier.

  The parameters included in the surface water chemistry analysis are sodium, potassium, calcium, magnesium, alkalinity (as CaCO3), chloride, fluoride, sulfate, bromine, ammonia (as N), Kjeldahl nitrogen, nitrate + nitrite, nitrite, nitrate, phosphorus, dissolved organic carbon, colour, conductivity, pH, turbidity, bicarbonate, carbonate, hardness, nitrogen (total), total dissolved solids, saturation pH, and the Langelier Index.  See Table 1.

  The parameters included in the surface water metals analysis are aluminum, antimony, arsenic, barium, beryllium, bismuth, boron, cadmium, calcium, chromium, cobalt, copper, iron, lead, lithium, magnesium, manganese, molybdenum, nickel, potassium, rubidium, selenium, silver, sodium, strontium, tellurium, thallium, tin, uranium, vanadium, and zinc. See Table 2.

Escherichia coli and total dissolved solids were also tested for. See Tables 3 and 4.

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