THE ACCUMULATION OF MERCURY IN THE MILL POND PARK OF THE PARK RIVER WATERSHED, NEWINGTON, CT

We investigated the sediment of a stream reach that contained elevated levels of total mercury (THg) that were found during a wide-scale study of the Park River watershed, a sub-watershed of the Lower Connecticut watershed. A section of the Mill Brook, at Mill Pond Park in Newington, CT contained sediment THg levels as high as 298 μg/kg, where the baseline concentrations across much of this urban stream were between 58 μg/kg and 191 μg/kg. In order to assess the accumulation of THg levels in the Mill Pond Park, 32 mud samples were collected and analyzed for THg concentration using a Milestone DMA-80 Total Mercury Analyzer. Percentages of organic materials were also analyzed using the loss on ignition method and later compared to the THg levels to see the relationship between organic carbon and THg. The locations and distribution of the samples were plotted using GIS. The highest concentrations of THg were observed in the sediments directly at and downstream of a storm water conduit that drains an adjacent bus parking lot. It is interpreted that since the Park River watershed contains a high percentage of impervious surfaces, airborne mercury accumulates in stream bedload deposits as a result of direct runoff. Future studies will investigate THg deposition and accumulations in the White Mountain National Forest of New Hampshire.