Historical contamination recorded in a coastal sediment core
- Texas A and M Univ., College Station, TX (United States)
- Texas A and M Univ., Galveston, TX (United States). Dept. of Oceanography
Organic and inorganic contaminant concentrations were determined in 1 cm sections from a 84 cm long sediment core collected from the submarine Mississippi River Delta (N 28{degree} 55.4827, W 89{degree} 40.6362). A sedimentation rate of 0.8 cm/yr was estimated from {sup 210}Pb and {sup 239,240}PU. Aluminum concentrations had only small fluctuation with depth, indicating approximately constant mineralogy for the entire core. Selected contaminant (Ag, Cd, Cr, Pb, chlordane, DDTs, PCBs, and PAHs) had higher concentration in recent surface sediments compared to older bottom sediments. Total DDT (sum of DDT, DDE, and DDD), PAHs, PCBs, and Pb increased above background concentrations in the mid-1940`s. While, chlordane, Ag, Cd and Cr show increased concentrations above background in the early 1950`s. Most of the contaminants reached maximum concentrations in the late 1970`s or early 1980`s. Interestingly after a decline Pb had an increasing trend over the last several years and total DDTs do not show a decreasing concentration trend. Several organic contaminants show a sharp increase in concentration between 1980 and 1988. Temporal contaminant distribution trends, inferred from depth, are complex. Contaminants in this core do not appear to have decreased in a predictable manner in response to environmental regulations. This may be the results of the complexity of sedimentary processes at this site.
- OSTI ID:
- 203588
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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