HEAVY METAL CONTAMINATION OF A RESTRICTED TIDAL MARSH OF THE SYBIL CREEK WATERSHED, BRANFORD, CT

Sybil Creek is a tributary of the Branford River, which discharges into Long Island Sound approximately five miles east of New Haven, Ct. The watershed area of Sybil Creek, at its Route 146 tidegate, comprises 232 acres, most of which are glaciated uplands. Degraded tidal wetlands consisting of three interconnected marshes, the Central Marsh (6.4 acres), the North Marsh (14.2 acres) and the East Marsh (52.6 acres) are scheduled for tidegate augmentation. By generating a higher tidal prism with more invigorated flow, restored circulation will encourage a natural succession of preferred salt marsh plants. Lying within the North Marsh is an area identified as an old landfill. Thick oily sediment discharges have been observed by the DEP at the road crossing at the marsh’s southern boundary. Fieldwork during the summer of 2000 was designed to sample these discharges and to test the water quality of tidal channels and pools up-gradient and down-gradient from the landfill site. Two sets of samples, totaling nineteen in number, were taken along the reaches of Sybil Creek at high and low tide. Standing water close to the landfill was also sampled. Samples were subjected to spectrophotometric analyses for select heavy metals using a HACH DRE 2010 Spectrophotometer. Ranges for the indicator metals currently run are as follows (Concentrations in mg/L): Copper 0.02 - 1.61, Manganese 0.0 - 2.1, KMnO 0.0 - 6.0, MnO4 0.0 - 4.5, Iron 0.0 - 3.26, Chromium (Cr6+) 0.01 - 0.14, NaCrO4 0.02 - 0.45, CrO4 0.02 - 0.32. Concentrations of heavy metals are roughly equivalent along the reaches of Sybil Creek during low and high tides. It is possible, however, that heavy metals are being contributed by the Branford River, equilibrating in the estuary, and are influencing the high tide values. Exceptionally high concentrations also occur in standing pools on the west slope of the landfill and in the tidal marsh adjacent to the Branford River estuary.