TRACE ELEMENTS ENRICHMENT IN STREAM SEDIMENTS ALONG NAUGATUCK RIVER, CONNECTICUT

The Naugatuck River which is about 40 miles long is a major river in the state of Connecticut. The river is the largest tributary of the Housatonic River, and it is the only river that flows entirely within the state (Connecticut). On October 27^th, 2017, several million gallons of raw sewage from Waterbury Sewage Treatment facility accidentally flowed into the Naugatuck River for five hours killing scores of fish in several towns. Also, on January 21^st, 2018, another accidental release of more than 1000 gallons of oil from Onlin Brass manufacturing facility spilled into Naugatuck River. All these have clearly impaired both the water, and sediment quality. However, there is scarcity of data on trace element concentration along the Naugatuck drainage system. This project examined the impact of accidental release on the chemical signature of fifteen chemical elements K, Al, Ca, Mg, Cr, Mn, Fe, Ni, Cu, p, Zn, Cd, As, Pb, and Na in the river sediments. A total of thirty seven (37) sediment samples were collected along the entire length of Naugatuck River, and analyzed for acid extractable, particle size distribution, organic matter contents, and soluble salts. Result of the particle size analysis using Hydrometer method showed that most of the sediments are sands, loamy sand, sandy loam, silty loam to silt. Chemical analysis on acid digested samples showed variability in average concentrations in order of abundance Al> Fe>Mg>Ca>P>Mn>Na>Zn> K>Cu>Cr>Pb>Ni>As>Cd. Fine grain sizes were positively correlated to geochemical data, an indication of possible partitioning to fine grain sizes. Calculations of element enrichment factors and geoaccumulation index revealed that most of the sediment samples were enriched, which is obviously related to anthropogenic activities. However, the enrichment is not correlated with any specific land use along the river.