Comparison of sperm viability with seminal plasma metal levels.

This study compares the semen levels of lead (Pb), cadmium (Cd), and aluminum (Al) in relation to live sperm in semen samples from 64 apparently healthy men. The measured levels were separated into live sperm count tertiles (<25% [18 subjects], 25-50% [26 subjects], and >50% [20 subjects]). The mean +/- SD for each group was calculated, and the difference between the means of the high and low tertiles were compared by ANOVA. Significant differences were observed between the high and low live sperm groups for Pb (p < 0.01) and Al (p < 0.05), but not Cd. Spearman's rank correlation between sperm viability and the semen plasma metal levels showed a direct relation to Mg (p < 0.05). However, there was an inverse relation to lead (p < 0.001), cadmium (p < 0.01), and aluminum (p < 0.01). There was no significant correlation between Ca and Zn. Linear regression between the live sperm counts and semen level of the three metals show that metal levels were inversely correlated with the percentage of live sperm (p < 0.001, < 0.01). Apparently, the presence of these metals in the environment and in seminal plasma exerts a toxic effect on sperm.