Trace metal residues in biota and sediments from Lake Pontchartrain, Louisiana

Pontchartrain lake, La., is a shallow oligohaline estuary in the deltaic plain of the Mississippi river; it has 3 indirect restricted connections to the Gulf of Mexico. The lake was used for recreational activities and fisheries, and was subject to pollution. A study was carried out to determine baseline values for 12 priority-pollutant trace metals in oysters, clams, and sediment at the entrances of the 3 connections to the lake. Analytical procedures are outlined, and the results are tabulated. Of the 12 metals tested, only thallium was not detected in mollusc tissue samples. The results are compared in tables with data from other Gulf Coast estuaries.