HEAVY METAL CONCENTRATIONS IN SALT MARSH SOIL AND PLANTS: CASE STUDY NEAR ST. SIMONS ISLAND, GA, USA

This study investigates the concentrations of heavy metals in the plants and soil of a salt marsh near St. Simons Island, GA, USA, and estimates the negative biological impact of these concentrations using established marine sediment quality guidelines. Salt marshes are coastal environments that serve many important ecological and economic functions. Heavy metal contamination poses a threat to marshes because nearly all heavy metals are toxic to plants and wildlife at elevated concentrations. The field site has experienced stress and dieback of its predominant grass Spartina alterniflora in the past decade, which has prompted investigations into soil and water quality parameters. This marsh is also bisected by a four-lane causeway and in proximity to an oil spill event that occurred in St. Simons Sound in 2019, which could both introduce trace heavy metals found in petroleum to the marsh. Eighteen surgical soil samples and eighteen green S. alterniflora leaves were collected at sampling sites along three lateral transects of the marsh, with samples being taken in both healthy and stressed areas of marsh. The soil and plant samples were analyzed for the elemental concentrations of cadmium (Cd), nickel (Ni), arsenic (As), zinc (Zn), chromium (Cr), and copper (Cu) using inductively coupled plasma mass spectrometry (ICP-MS). We will present preliminary data regarding the distribution of observed heavy metal concentrations across the marsh platform. This analysis will be conducted using geospatial software to analyze spatial trends in individual elemental distribution, sediment quality based on established guidelines, and relationships to degree of plant dieback.