Elevated dentine lead levels in adult teeth of First Nation people from an isolated region of northern Ontario, Canada.

Lead is neither essential nor beneficial to living organisms, being a toxin that adversely affects humans exposed to it, even at low doses (USCDC 1991). In the past, lead was present in a variety of environmental media, such as food, drinking water, air, soil/dust, and consumer products. In the last two decades, lead levels in the different environmental media have been decreased or eliminated in North America (USCDC 1991). However, a significant source of environmental lead exposure still exists in the form of lead shot used in hunting (e.g. Tsuji and Nieboer 1997). Two criteria commonly used to assess lead levels in humans are blood and tooth lead concentrations. Because elevations in blood lead are transitory reflecting only recent exposure of one to two months and other types of samples, such as, hair and nail risk external contamination, the study of dentine lead levels in human teeth has become more popular (e.g., Shapiro et al. 1972; Bercovitz et al. 1993). Since lead is deposited permanently in dentine of teeth, analysis of lead content in dentine can be used as an indicator of chronic lead exposure in humans (Bercovitz et al. 1993). In the western James Bay region of northern Ontario, Canada, all communities are fly-in with no road access. In the most industrialized town of the region, Moosonee, water and soil lead levels have been found to be very low and not of importance as an environmental exposure factor for humans (OMHE 1989). Similarily, air lead levels have been found to be well below the Ontario Ambient Quality Criterion of 5 μg/m 3 (OMHE 1989). Only two possible sources of environmental lead exposure have been identified for people of this region: white lead used in boat repairs and lead shot contaminated wildmeats (OMHE 1989; Smith 1995; Tsuji and Nieboer 1997). White lead is an unlikely source with only small quantities being sold in the region (Smith 1995). In addition, white lead users are aware of the required safety procedures (Smith 1995). In this paper, lead levels in teeth collected from adults of Fort Albany, Ontario (western James Bay region) were compared to lead levels found in other