Water Quality Assessment of Newton Creek and Its Effect on Hog Island Inlet of Lake Superior

摘要

A study of water quality was conducted for Newton Creek that flows in an urban area in the city of Superior and discharges into Hog Island Inlet (HII). Water quality data were collected from five locations located along the creek flow from its head to its mouth. Throughout the year there was a wide range in measured values for the temperature, dissolved oxygen (DO), electro conductivity (EC), and pH. These ranges showed there were numerous factors affecting these properties of the creek, with the impact from oil refinery being the greatest. Some of the recorded salinity was observed to be much greater than the acute criteria. The high salinity of the creek water is attributed to the chloride and sodium concentrations with relatively elevated concentrations of sulfate and nitrate. A geochemical model revealed that the water chemical composition of HII was the result of a mixing ratio of about 90%of Lake Superior water and 10 % of Newton Creek water. Faxon Creek, which was monitored for comparison purposes, recorded salinity concentrations much higher than the salinity of Newton Creek. Both Newton and Faxon creeks revealed different chemical makeup. Faxon Creek revealed that all major cation and anion concentrations in its water were higher than in Newton Creek waters with the exception of potassium, sulfate and nitrate. Nitrate and phosphorous concentrations in Newton Creek are much higher than in Faxon Creek and all the surface water in the area, and they exceed the recommended concentration values set by U.S. Environmental Protection Agency (EPA). The chemical makeup and the variation of the major ions in both creeks show that the source of water contamination in Newton Creek originates mainly from the discharge of oil refinery treated wastewater with minimum contribution from surface runoff. The source of contamination and mainly the elevated salinity in Faxon Creek water is mainly from urban surface runoff from the city of Superior.