Water hardness in relation to cadium accumulation and microscopic signs of cardiovascular disease in horses.

The hardness of drinking water (i.e., the sum of calcium and magnesium concentrations) has been related to cadmium concentration in kidney cortex and to microscopic signs of arteriosclerosis and focal myocardial fibrosis in 50 Swedish horses slaughtered for meat production. A significant negative correlation was found between water hardness and cadmium concentrations in kidney cortex. This indicates that horses living in soft water areas are more inclined to accumulate cadmium from the general environment. Microscopic changes in the aorta and myocardium were approximately 2 times as frequent in horses that drank soft water compared to horses that drank hard water. The differences were, however, not statistically significant. It is concluded that horses are well suited for studies of the "water factor".