Monitoring changes in salinity and metal concentrations in New Jersey (USA) coastal ecosystems Post-Hurricane Sandy

Temporal changes in pore-water salinity and metal concentrations were investigated in soils from two sites (residential and wetland areas) located in the Old Bridge Township, NJ, after Hurricane Sandy hit the Northeast of the United States of America. Core and surface soil samples were collected in both the residential and wetland sites and then analyzed by field portable X-ray fluorescence (NITON XL3t-600 series FP-XRF). Pore-water salinity was determined from continuous measurements (every 10 min) of conductivity in a single sampling well installed in the wetland site. One month after Hurricane Sandy, pore-salinity was as high as 27 g/L, but gradually decreased to 15 g/L in approximately 3 months. Then, it increased gradually to 26 g/L 3 months later. High metal concentrations (lead, arsenic, copper, chromium, and iron) were measured in the surface and top 2-cm soil layer in both residential and wetland sites, often exceeding background levels within weeks of Hurricane Sandy. These metal contaminations were interpreted as being associated with storm surge from Hurricane Sandy that caused substantial flooding of the coastal areas by large amounts of seawater, loaded with dissolved metal and adsorbed metals to suspended sediments from the Raritan Bay Slag Superfund site. The changes in salinity in wetland areas indicated the intrusion of seawater, thus providing evidence for metal-contaminated seawater altering the wetland’s geochemistry. The transport and deposition of metal contaminants in the coastal areas by Hurricane Sandy increased the risk of human exposure to these contaminants.