Exposure can occur from inhalation of lead fumes and particles (e.g., from smelting) or from ingestion of lead-contaminated dust (for example, from decaying lead paint), water (from leaded pipes) and food (from lead-glazed or lead-soldered containers).
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发生这种接触的时间可能较短(急性中毒),也可能较长(慢性中毒)。
This exposure may occur over a short period (acute poisoning) or over a prolonged period (chronic poisoning).
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迄今尚未确定没有有害影响的铅接触水平。
No level of exposure to lead that is without harmful effects has so far been identified.
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因此,一些卫生部门确定,血铅浓度高于整体人口参照值,即为过度接触。
As a consequence, some health authorities define excessive exposure as having a blood lead concentration above the reference value for the population as a whole.
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该参考值通常是代表人口前2.5%或5%(即百分位第97.5位和95位)的血铅浓度。
This reference value is usually the blood lead concentration that characterises the top 2.5% or 5% of the population, i.e., the 97.5th or 95th percentile, respectively.
For example, in the USA, the Centre of Disease Control and Prevention lowered its blood lead reference value to 3.5 µg/dL for children ages 1-5 years in October 2021 (2) , in France, 5 µg/dL is the 98th percentile value for children under 7 years (3).
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而法国7岁以下儿童的第98百分位值为5µg/dL (3) 。
WHO recommends that for an individual with a blood lead concentration 5 µg/dL, the source(s) of lead exposure should be identified and appropriate action taken to reduce and terminate exposure (4).