Canadian researchers have warned that many off-the-shelf brewed teas purport- edly contain lead in excess of levels considered safe for pregnant and lactating women. Gerry Schwarlfenberg, et al., “The Benefits and Risks of Consuming Brewed Tea: Beware of Toxic Element Contamination,” Journal of Toxicology, December 2013. Using 30 samples of black, green, white, and oolong teasobtained from supermarkets and health food stores, the study’s authors steeped the teas using one tea bag and 250 mL of distilled water for 3-4 minutes and 15-17 minutes

The results evidently showed that “all brewed teas contained lead,” with 73 percent of teas brewed for three minutes and 83 percent of teas brewed for 15 minutes having lead levels ranging from 0.1 μgm/L to 4.39 μgm/L. According to the study, California’s Proposition 65 currently sets an acceptable limit for lead in reproductive health at 0.5 μgm/L per day. In addition, the study notes that aluminum levels exceeded recommended guidelines in 20 percent of brewed teas.

“Toxic contamination by heavy metals was found in most of the teas sampled. Some tea samples are considered unsafe,” conclude the study’s authors. “There are no existing guidelines for routine testing or reporting of toxicant levels in ‘naturally’ occurring products. Public health warnings or industry regulation might be indicated to protect consumer safety.” See National Post, December 1, 2013.