Significant amounts of sodium and potassium may be present in dissolved mineral salts that pass undigested through animals after consumption of feed. Calcium, magnesium, chloride, sulfate, bicarbonate, carbonate, and nitrate also may contribute to the salinity of manure. Relatively low levels of salts can increase blood pressure in sensitive individuals, thus increasing their risk of heart attacks and strokes. Few drinking water treatment processes are capable of removing salts. Increasing salinity can disrupt the balance of fresh water ecosystems, making it difficult for native species to thrive.
Dairy cattle wastes have been blamed as the cause of elevated salinity levels in groundwater (Harter et al.,2002a,2002b). Wastes with high salt levels that are applied to land can also contaminate groundwater, adversely impact soil structure, reduce soil permeability, and reduce crop yields (USEPA, 2003a).