UPTAKE OF CS-137 IN VEGETABLE CROPS GROWN ON A CONTAMINATED LAKEBED

Mean concentrations and plant:soil concentration ratios of Cs-137 mere determined for six vegetable crops grown on an exposed, contaminated lakebed of a former reactor cooling reservoir in South Carolina. Each crop species was grown with or without potassium fertilizer, Selected crops were also irrigated with either reservoir water or groundwater. Subsamples of crops were prepared for human consumption before analysi s to determine the extent of any loss. Plant:soil concentration ratios (dry basis) ranged from 0.22 to 6.82, values which were substantially higher than those used in generic assessment models. While there was no statistically significant effect of irrigation source or culinary p reparation, the effect of potassium-fertilizer was dramatic. In many c ases, concentrations of Cs-137 in, those plants receiving potassium me re less than half of the concentrations in plants that did not receive potassium. Significant differences among species and plant parts for Cs-137 concentrations were observed, Dose/risk calculations for the in gestion of these vegetables by a hypothetical 30-y resident indicates the possibility of a lifetime fatal cancer risk well-above the U.S. En vironmental Protection Agency's regulatory guideline of 10(-4).