DETERMINATION OF CADMIUM, CHROMIUM, COPPER, IRON, LEAD, AND ZINC IN OYSTERS FROM SOUTHWEST LOUISIANA BY INDUCTIVELY COUPLED PLASMA-OPTICAL EMISSION SPECTROMETRY

Abstract

This article presents a follow-up, a more comprehensive and extensive study to a previous, but limited study on three metals in oysters from the West Cove area of Lake Calcasieu in Southwest Louisiana. Results from a two-sampling period in mid-October and mid-December 2009 showed concentrations levels in μg/g (mean of 15 oysters, ± standard deviation, and range) as determined by inductively coupled plasma-optical emission spectrometry (ICP-OES) of cadmium, 5.0, ±0.5, 4.0–6.3, and 3.0, ±0.5, 1.8–5.3; chromium, 3.1, ±0.6, 2.0–3.6, and 1.7, ±0.6, 0.7–3.0; copper, 125.0, ±115, 58–245, and 115, ±45, 76–228; iron, 224, ±66, 142–403, and 311, ±111, 160–559; lead, 3.4, ±0.7, 1.6–5.8, and 4.7, ±2.3, 0.7–13; and zinc, 1859, ±774, 740–3471, and 1578, ±783, 692–3056. These concentrations were lower by at least a factor of 10 from the previous study on cadmium and lead but similar to store-bought oysters. The two sampling period concentrations were not statistically different for the two sampling month periods. The lowering of the concentration was attributed to a cleaner (from metals) oyster beds. Results of the six metals from soils in six different sites in the oyster beds showed comparable or slightly higher concentrations than the oysters. Water samples from the six sites were low, or below the detection limit of the ICP-OES instrument.

Keywords:

• cadmium
• chromium
• copper
• inductively coupled plasma-optical emission spectrometry
• iron
• lead
• oysters
• soils
• Southwest Louisiana
• zinc

ACKNOWLEDGMENTS

One of the authors, PRMS, is thankful for the award of the Mark S. Delaney Summer Research Fellowship in the Chemistry Department at McNeese State University for Summer 2009, from the Southwest Louisiana section of the American Chemical Society (SWLa-ACS).