Chalk Point: A Case Study of the Impact of Brackish Water Cooling Towers on an Agricultural Environment
1982
Mulchi, Charles L. | Armbruster, James A. | Wolf, D. C.
The construction of two brackish water, natural-draft cooling towers (Units 3 and 4) by the Potomac Electric Power Co. at their Chalk Point Generating Station, located in a major agricultural region in southern Maryland, aroused concern that saline aerosol emissions from the facility might significantly impact the crops and soils near the facility. Permanent research and monitoring sites were established at distances of 1.6, 4.8, and 9.6 km north, east, south, and west from the cooling towers. Over the period May 1973–May 1980, baseline and postoperational information was obtained on monthly Na and Cl deposition rates; foliar chemistry and yields of corn (Zea mays L.) and soybeans (Glycine max L. (Merr.)); soil pH and extractable P, K, Ca, Mg; Na; and electrical conductivity values on 0- to 15-cm depth soil samples. Unit 3 began operations in July 1975. The quantities of saline aerosol emissions from Unit 3 were insufficient to cause detectable changes in the Na and Cl deposition rates above baseline values at or beyond the 1.6-km sites, the closest agricultural areas to the power plant. Also, no significant changes were observed in Na and Cl levels in vegetative samples collected from corn and soybeans grown in the research sites after Unit 3 began operations. Significant reductions in corn yields that were more associated with rainfall patterns than to salt emissions were observed during post-Unit 3 operations. Significant changes that, in most cases, could be closely associated with the general increases observed in soil acidity, were observed in each of the soil chemistry parameters with time. In conclusion, saline aerosol emissions from Chalk Point Unit 3 natural draft cooling tower did not have a detectable impact on the agricultural crops and soils adjacent to the emission source.
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