Reproductive Effects and Duckling Survivability Following Chronic Dosing With Tungsten-Iron and Tungsten-Polymer Shot in Adult Game-Farm Mallards

Abstract

Tungsten-iron and tungsten-polymer shot were given conditional approval for waterfowl hunting by the U.S. Fish and Wildlife Service based partly on the results of a 30-day acute toxicity trial utilizing mallards (Anas platyrhynchos). Final approval of the two tungsten-containing shot was contingent on the results of a 150-day study that assessed the health and reproductive effects of tungsten-iron and tungsten-polymer shot in adult mallards. Reproductive data are presented in this paper. Sixteen male and 16 female adult mallards were dosed orally with eight #4 steel shot (control), eight #4 tungsten-iron shot, or eight #4 tungsten-polymer shot on days 0, 30, 60, 90, and 120 of a 150-day trial (26 January 1998 to 25 June 1998). Reproductive performance was assessed during the last 90 days (day 61 to day 150) of the trial. There were no significant differences in egg production and fertility and hatchability of eggs from tungsten-iron-and tungsten-polymer-dosed ducks compared to control ducks. There was no evidence of differences in percent survivability and body weight of ducklings from tungsten-iron and tungsten-polymer mallards compared to ducklings from control ducks. Tungsten-iron or tungsten-polymer shot repeatedly administered to adult mallards during the 150 day trial did not adversely affect reproduction or their offspring.

Hematological Effects and Metal Residue Concentrations Following Chronic Dosing With Tungsten-Iron and Tungsten-Polymer Shot in Adult Game-Farm Mallards

“…In general, the concentration of iron was highest in the tissue samples from the tungsten-iron-dosed and control ducks and higher in females than males. The high concentration of iron in liver samples from control and tungsteniron-dosed ducks agreed with the histological documentation of hemosiderosis (Mitchell et al, 2001a). Locke et al (1967) dosed mallards with eight pellets of iron shot, which resulted in hemosiderosis of the liver and elevated hepatic iron concentrations.…”

“…The increase in uric acid concentration is thought to be a result of a decreased rate of tubular excretion plus poor nutritional status, which can cause an increase in uric acid production as body proteins are degraded (March et al, 1976;Campbell and Coles, 1986). Renal tubular damage was documented in the kidneys from lead-dosed ducks in the present study (Mitchell et al, 2001a). The hepatic enzymes alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase can be useful diagnostic tests to determine lead poisoning in mallards.…”

“…Six male/female pairs were administered by gavage eight pellets of #4 lead shot (97% lead, 3% antimony; positive control) on day 0. The dosing procedure was described in Kelly et al (1998) and the husbandry was described in Mitchell et al (2001a).…”

“…On day 150 of the trial, all surviving ducks were killed by cervical dislocation and necropsied as described in Mitchell et al (2001a). The right femur and portions of the liver, kidneys, and testes or ovary were frozen and shipped to CT&E Environmental Services (Ludington, Michigan, USA) for analysis of iron and tungsten.…”

Embedded Metal Fragments

“…Primarily, these investigations have focused on the safety of implanted medical devices (International Agency for Research on Cancer [IARC], 1999) and the development of "nontoxic" hunting ammunition (Brewer, Fairbrother, Clark, & Amick, 2003;Kelly et al, 1998;Kraabel, Miller, Getzy, & Ringelman, 1996;Mitchell et al, 2001a;Mitchell et al, 2001b;Mitchell et al, 2001c). Little has been done throughout the years to assess the long-term health effects of military-relevant metals and metal mixtures (Kane, Kasper, & Kalinich, 2009).…”