Determining the background levels of bismuth in tissues of wild game birds: a first step in addressing the environmental consequences of using bismuth shotshells.

Bismuth shotshells have been approved as a "nontoxic" alternative to lead in North America. Approval was based on a limited number of studies; even background levels of bismuth in wildfowl were unknown. We report on the concentration of bismuth (and lead) in muscle and liver tissues of wildfowl (Anas platyrhynchos, Anas acuta, Anas crecca, Branta canadensis, Chen caerulescens) harvested with lead shotshell. Average liver-bismuth levels detected in the present study (e.g., teal, 0.05 microg/g dw; mallard, 0.09 microg/g dw) suggest analytical error in other studies examining the effects of bismuth in birds. Significant positive relationships between bismuth- and lead-tissue levels for muscle when all species were combined (and for B. canadensis and C. caerulescens separately) can be explained by noting that bismuth is a contaminant of lead. Thus, more research is recommended to confirm the appropriateness of bismuth as a "nontoxic" shot alternative.

Testing the validity of a critical sulfur and nitrogen load model in southern Ontario, Canada, using soil chemistry data from MARYP.

The validity of a steady-state mass balance model (Arp et al., 1996; referred to as ARP) was tested using physicochemical soil data from the Monitoring Acid Rain Youth Program (MARYP). Four ARP sites were matched with ten MARYP sites according to proximity, bedrock type and subsoil pH to test the validity of the ARP model for critical load exceedances. Soil solution pH, base concentration and A1 concentration from MARYP sites, which were well matched to ARP sites, validated the modelled critical load exceedances. Higher exceedance areas were associated with more acidic pH and lower base and higher A1 concentrations from matched MARYP sites and vice versa. One ARP site was inappropriately matched with MARYP sites and could not be validated using base and A1 concentrations. This study also confirmed the southern limit of the zero critical load exceedance isopleth from the model. However, variability of the other exceedance isopleths was noted due to the limited number of sites used in the model. The validation of these sites in the ARP model and the zero critical load exceedance isopleth nonetheless allows greater confidence in using this model as a management tool for acidic deposition.

Elevated dentine-lead levels in deciduous teeth collected from remote first nation communities located in the western James Bay region of northern Ontario, Canada.

Teeth were collected from First Nation schoolchildren inhabiting the remote western James Bay region of northern Ontario, Canada. Lead levels in dentine chips were determined by graphite furnace atomic absorption spectrometry, for naturally exfoliated deciduous teeth. Within exfoliated teeth (one tooth supplied per person), no significant differences in lead concentrations between tooth type were found (P = 0.36). The mean lead concentration of exfoliated teeth of 9.2 microg g(-1) dry weight (N = 61) from this remote region was comparable to levels reported by others for children inhabiting urban centers or residing near smelters. Further, 24.6% (N = 15) had elevated dentine-lead levels ( > 10 microg g(-1)). Lead levels in soil, water, and air have been reported as being low and unimportant sources of exposure for people of the western James Bay area. Evidence is reviewed suggesting that lead contaminated game meat was one source of environmental lead exposure. Consumption data indicate that wildlife is still an important food source for First Nation people of the western James Bay region; 98% (46/47) of the children surveyed consumed some type of wild meat.