Effect of Drinking Desalinated Seawater on Copper, Zinc, Calcium, Magnesium and Iron in Rats Blood

Objectives To analyse the components of desalinated seawater and determine the content of blood copper, zinc, calcium, magnesium and iron in rats drinking desalinated seawater, to evaluate the effect of drinking desalinated seawater on blood copper, zinc, calcium, magnesium and iron of rats.

Methods Twenty sensory characteristics and chemical indexes and 73 toxicological indexes of desalinated seawater were analysed to confirm if they were accorded with the "Hygienic Standard for Drinking Water" (GB 5749-2006). Then, the blood copper, zinc, calcium, magnesium and iron contents of rats drinking municipal tap water (control group) or desalinated seawater (test group) were determined, and the copper-zinc ratio and calcium-magnesium ratio were calculated.

Results The sensory characteristics and chemical indexes of desalinated seawater were qualified; the chromacity was < 5, the pH value was 6.94, showing a faint acidity. Total dissolved solids was 186 mg/L and total hardness was 13 mg/L in desalinated seawater, which were all accorded with the hygienic standard for drinking water. While the content of boron (1.3 mg/L) was higher than the upper limit (≤ 0.5 mg/L); fluoride (0.02 mg/L) was lower than the limit (≤1 mg/L) of the standard; and other indexes were not detectable. Blood copper and copper-zinc ratio in rats drinking desalinated seawater for 180 d was higher than the rats drinking municipal tap water (control rats). Blood calcium and calcium-magnesium ratio in rats drinking desalinated seawater for 90 d were higher than the control rats. Blood magnesium and iron in rats drinking desalinated seawater for 180 d were lower than the control rats. While blood calcium-magnesium ratio in rats drinking desalinated seawater for 180 d was higher than the control rats.

Conclusions The increase of blood copper and cooper-zine ratio, and the drop of blood iron level in rats, might be induced by drinking desalinated seawater for 180 d. While the calcium-magnesium ratio in rats would be increased after drinking desalinated seawater for 90~180 d.