Ward N I, Brooks R R, Roberts E
Bull Environ Contam Toxicol. 1978 Jul;20(1):44-51. doi: 10.1007/BF01683484.
The lead content of whole blood of 62 sheep grazed continuously for 6 months near a major highway was compared with 38 sheep from a nearby uncontaminated area. Mean values of 0.90 and 0.20 microgram/ml were obtained. Four sheep from the contaminated area were placed in an uncontaminated paddock and the lead content of the blood decreased rapidly during the first 10 days and thereafter more slowly. After 185 days, blood lead levels had still not quite reached normal levels. Animal from an uncontaminated area showed an immediate rise in the blood lead levels when placed near a major highway. Sheep placed in a concrete pen away from motor vehicle exhaust emissions showed a rise in lead levels when fed with forage cut from the verges of a busy highway. Sheep placed near a highway and fed with forage from an uncontaminated area showed an increase of lead levels in the blood, comparable to that of the previous experiment. It was concluded that lead uptake by ingestion of polluted forage and by inhalation of airborne particulates are both mechanisms responsible for enhanced lead levels in ovine blood.
将在一条主要公路附近连续放牧6个月的62只绵羊的全血铅含量，与来自附近未受污染地区的38只绵羊进行了比较。得到的平均值分别为0.90微克/毫升和0.20微克/毫升。将来自污染地区的4只绵羊置于未受污染的围场中，血液中的铅含量在最初10天迅速下降，此后下降速度较慢。185天后，血铅水平仍未完全恢复到正常水平。来自未受污染地区的动物被放置在主要公路附近时，血铅水平立即上升。放置在远离机动车尾气排放的混凝土围栏中的绵羊，当喂食从繁忙公路边缘割下的草料时，铅含量上升。放置在公路附近并喂食来自未受污染地区草料的绵羊，血液中的铅含量增加，与之前的实验相当。得出的结论是，摄入受污染的草料和吸入空气中的颗粒物导致铅摄入，这两种机制都是绵羊血液中铅含量升高的原因。
