Apostoli P, Alessio L
Cattedra di Medicina del Lavoro, Università degli Studi di Brescia.
Med Lav. 1992 Nov-Dec;83(6):539-56.
Present lead (Pb) exposures in working and general environments are undoubtedly lower than several decades ago so that mean blood lead levels (PbB) in the main industrial sectors using lead, such as ceramics and accumulator manufacturing, are now about 30 micrograms/100 ml and in the general population between 10 and 15 micrograms/100 ml and in some situations decidedly below 10 micrograms/100 ml. At the same time increasingly more accurate and sometimes original knowledge has been acquired on the effects of low-level Pb exposure, especially the effects on the nervous system, the cardiovascular system, the endocrine and immune systems, on heme-containing enzymes, and on the reproductive system. The question of a possible mutagenic and carcinogenic action of Pb is, however, still open. It is also clear that many of the above effects were observed for PbB levels considerably below the current limit levels. For certain effects, like those on heme, the central nervous system, and blood pressure, it has not been possible to establish a threshold below which they will not occur. With effects that are so different in nature and degree and with changed exposure conditions, a critical re-examination of the assumptions on which current knowledge and prevention models are based appeared appropriate. In particular, action models are proposed for discussion which, besides the priority aim of restricting use of Pb to those situations where there is no alternative and to those working environments which guarantee compliance with modern regulations and prevention procedures, have two differentiated objectives: the first is to eliminate the dose-dependent effects occurring at exposures higher than those in the general population; the second is to reduce to the lowest possible level the effects with no threshold or with as yet unestablished threshold, by means of actions in favour not only of occupationally exposed groups but also the general population.
目前，工作环境和一般环境中的铅（Pb）暴露量无疑低于几十年前，因此，在使用铅的主要工业部门，如陶瓷和蓄电池制造业，平均血铅水平（PbB）现在约为30微克/100毫升，而普通人群的平均血铅水平在10至15微克/100毫升之间，在某些情况下肯定低于10微克/100毫升。与此同时，人们对低水平铅暴露的影响，特别是对神经系统、心血管系统、内分泌和免疫系统、含血红素酶以及生殖系统的影响，已经获得了越来越准确、有时甚至是全新的认识。然而，铅可能的诱变和致癌作用问题仍然没有定论。同样明显的是，上述许多影响是在血铅水平远低于当前限值的情况下观察到的。对于某些影响，如对血红素、中枢神经系统和血压的影响，尚未确定一个不会产生这些影响的阈值。由于这些影响在性质和程度上差异很大，且暴露条件发生了变化，因此，对当前知识和预防模式所基于的假设进行批判性重新审视似乎是合适的。特别是，提出了一些行动模式供讨论，这些模式除了将铅的使用限制在没有替代方案的情况以及保证符合现代法规和预防程序的工作环境这一首要目标外，还有两个不同的目标：第一个目标是消除在高于普通人群暴露水平时出现的剂量依赖性影响；第二个目标是通过采取不仅有利于职业暴露人群而且有利于普通人群的行动，将无阈值或尚未确定阈值的影响降至尽可能低的水平。
