Meteorological effects on trace element solubility in Mississippi coastal wetlands

Abstract

Trace elements (TEs) vary in toxicity and should be closely monitored to manage their accumulation in marine organisms, which may pass on to the food web. This study utilizes the National Oceanic and Atmospheric Administration’s (NOAA), Data Integration Visualization Exploration and Reporting (DIVER), National Centers for Environmental Information (NCEI), and Drought Monitor Systems to acquire arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), and zinc (Zn) concentrations in marsh soils along the Mississippi Gulf Coast area using the precipitation and drought data for the two sampling periods in 2010 and 2011. Results revealed that Zn had a significantly high correlation (r = 0.80 and p < 0.05) between soil concentrations and daily rainfall amounts, whereas Pb concentrations in soil were shown to occur after heavy storms. There was also significant variation between the months for Cd, Cr, and Pb, over the sampling periods. Arsenic remains relatively stable and statistically similar in the sediment averaging 21.09 µg/kg. Coastal soils were significantly higher in Cd and Cr concentrations in 2010 (28.89 µg/kg for Cd and 28.91 µg/kg for Cr) compared to 2011 (both 9.16 µg/kg). The trace elements, Cd and Cr showed negative correlation (r = −0.63 and −0.27) to increasing drought intensities. Most of these responses can be explained by a redox process where TEs were sequestered or released as solids and subsequently becomes saturated or dried out. It was observed that soils in Mississippi’s Gulf Coast study areas have the ability to be a sink or reservoir during various weather conditions thereby entrapping or releasing TEs, which becomes more available to organisms.

Keywords

• estuary| trace elements| coastal wetlands| Mississippi gulf coast| weather