Calle P P, Kowalczyk D F, Dein F J, Hartman F E
J Am Vet Med Assoc. 1982 Dec 1;181(11):1299-301.
Mallards and black ducks (n = 409) killed by hunters during the 1980 and 1981 hunting seasons in Pennsylvania (Susquehanna River and Crawford County) were examined to evaluate the effectiveness of regulations that converted the studied areas from lead to steel shotgun pellets in 1977-1978. Gizzards were examined for ingested lead and steel shot, and liver specimens were analyzed for lead. Since there is no evidence to suggest that ducks preferentially ingest steel or lead shot, it was concluded that ducks with steel shot would have contained lead shot. Therefore, we concluded that the conversion to steel shotgun pellets accounted for the decreased prevalence of ingested lead shot from 11.2% to 5.6%. Toxic concentrations of lead (greater than or equal to 6 ppm, wet weight) in the liver were found in 6 of 23 ducks that contained lead shot, whereas only 2 of 386 ducks without lead pellets had toxic concentrations. It was concluded that the conversion to steel shotgun pellets in the studied areas probably has decreased the exposure of ducks to lead shot, thereby decreasing the potential for lead poisoning.
对1980年和1981年狩猎季节期间在宾夕法尼亚州（萨斯奎哈纳河和克劳福德县）被猎人捕杀的绿头鸭和黑鸭（n = 409）进行了检查，以评估1977 - 1978年将研究区域的猎枪子弹从铅弹转换为钢弹的规定的有效性。检查砂囊以确定摄入的铅弹和钢弹情况，并对肝脏标本进行铅分析。由于没有证据表明鸭子会优先摄入钢弹或铅弹，因此得出结论，体内有钢弹的鸭子体内也会有铅弹。因此，我们得出结论，转换为钢质猎枪子弹导致摄入铅弹的比例从11.2%降至5.6%。在23只含有铅弹的鸭子中，有6只鸭子肝脏中的铅浓度达到有毒水平（湿重≥6 ppm），而在386只没有铅弹的鸭子中，只有2只鸭子的肝脏铅浓度达到有毒水平。得出的结论是，研究区域转换为钢质猎枪子弹可能减少了鸭子接触铅弹的机会，从而降低了铅中毒的可能性。
