Application for Approval of Tin Shot as Nontoxic for Waterfowl Hunting

Summary

The U.S. Fish and Wildlife Service (Service) has reviewed the International Tin Research Institute, Ltd.'s (ITRI) application for approval of tin shot as nontoxic for waterfowl hunting in the United States. The Service has found that the Tier 1 test results are inconclusive and Tier 2 testing is required before further consideration.

Full text

Department of the Interior

Fish and Wildlife Service


Application for Approval of Tin Shot as Nontoxic for Waterfowl 
Hunting

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of decision.

SUMMARY: The U.S. Fish and Wildlife Service (Service) has reviewed the 
International Tin Research Institute, Ltd.'s (ITRI) application for 
approval of tin shot as nontoxic for waterfowl hunting in the United 
States. The Service has found that the Tier 1 test results are 
inconclusive and Tier 2 testing is required before further 
consideration.

FOR FURTHER INFORMATION CONTACT: Paul R. Schmidt, Chief, or Carol 
Anderson, Wildlife Biologist, Office of Migratory Bird Management 
(MBMO), (703) 358-1714.

SUPPLEMENTARY INFORMATION: Since the mid-1970s, the Service has sought 
to identify shot that, when spent, does not pose a significant toxic 
hazard to migratory birds and other wildlife. Currently, only bismuth-
tin and steel shot are approved by the Service as nontoxic. Tungsten-iron shot received temporary conditional approval 
for the 1997-98 hunting season. The Service believes approval for other 
suitable candidate shot materials as nontoxic is feasible.
    On February 10, 1998, the Service announced its intention to review 
ITRI's Tier 1 information for approval of pure tin shot as nontoxic 
pursuant to 50 CFR 20.134 (recently amended--see 62 FR 63608, December 
1, 1997). The Service has determined that the Tier 1 test results are 
inconclusive. The Service requires that the Tier 2 test be completed 
before nontoxic approval of the tin shot can be considered. For a 
complete review of the tin shot application and review process, refer 
to the Supplementary Information Section of the February 10, 1998, 
Federal Register (63 FR 6766).
    ITRI submitted a Tier 2 test protocol to conduct an in vitro test 
to determine the erosion rate of the candidate shot and an acute 
toxicity test to determine the short-term effects of the candidate shot 
on game-farm mallards (Anas platyrhynchus) using commercially available 
duck food. The test protocol has been reviewed and approved by the 
Service, with technical assistance provided by the U.S. Geological 
Survey's Biological Resources Division. The general outline of the in 
vitro and acute toxicity tests given below is not a complete 
description of the testing protocol, but gives the basic outline of the 
test procedures being conducted.

In vitro test procedures:

    Five #4 each of tin, steel, and lead shot pellets were separately 
placed in 15 100 ml screw-top pyrex bottles. These bottles were filled 
with 100 ml of a sodium chloride-pepsin (20 g/l) solution. The samples 
were maintained at 42 deg.C and continuously stirred using a magnetic 
stirrer for 14 days. Each day 1 ml of solution was sampled and analyzed 
for metal content. Tin solutions were analyzed using an ICP with 
dilutions of the samples at 10 and 20 times in 10 percent hydrochloric 
acid. The lead solutions were analyzed using flame atomic absorption 
spectroscopy with dilutions at 10 and 50 times in 5 percent nitric 
acid. Steel solutions were analyzed using flame atomic absorption 
spectroscopy with dilutions at 10 and 50 times in 10 percent 
hydrochloric acid.

In vitro results:

    The average increase of metal concentration in solution per day was 
calculated to be 116 ppm for lead, 58.1 ppm for iron (from the steel 
shot), and 26.7 ppm for tin. Extrapolation of these dissolution rates 
shows that complete dissolution of one #4 tin shot takes twice the time 
for dissolution of steel shot and over three times for dissolution of 
lead shot under conditions simulating a waterfowl gizzard.

Acute toxicity test procedures:

    Two sets of eight pairs of mallards will be dosed with the 
candidate shot. One group will be fed a balanced diet, while the other 
is fed a nutritionally deficient (whole corn) diet. Another eight pairs 
will be dosed with steel shot, while three pairs each will be sham- and 
lead-dosed. All mallards will be housed outdoors during the winter at 
low temperatures. All groups, except the sham-dosed group, will be 
dosed with 8 #4 pellets of the appropriate shot type. Birds will be 
observed for 30 days for toxicological responses, shot retention will 
be monitored radiographically, and hematological and biochemical 
parameters will be monitored during the study. Selected tissues (liver, 
kidney, femur, and gonads) will be collected for histopathological 
evaluation and residue analysis.
    If the Tier 2 data result in a preliminary determination that the 
candidate material does not impose a significant danger to migratory 
birds, other wildlife, and their habitats, the Service will propose to 
approve this shot based on the toxicological report and toxicity 
studies and explain why Tier 3 testing is unnecessary. If the results 
are not conclusive or as a result of the public comment period, the 
Service determines that the information does not establish that the 
shot does not impose a significant danger to migratory birds, other 
wildlife, and their habitats, Tier 3 testing will be required and a 
Notice of Review published in the Federal Register.

Authorship

    The primary author of this notice of application is Carol Anderson, 
Wildlife Biologist, Office of Migratory Bird Management.

Dated: March 19, 1998.
Daniel M. Ashe,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 98-8552 Filed 3-31-98; 8:45 am]
BILLING CODE 4310-55-F  

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