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The principles of toxicology environmental and industrial applications 2nd edition phần 9

Loại nấm này tạo ra một đa dạng của các amin hữu cơ mà hành động như các chất chủ vận trên thụ thể alpha adrenergic loại bao gồm cả ergotamine, được sử dụng trong điều trị để điều trị chứng đau nửa đầu. | 19.4 PETROLEUM HYDROCARBONS ASSESSING EXPOSURE AND RISK TO MIXTURES 483 Interpretation of Risk Assessment Results and Comment For pregnant workers this indicates that there is a 5 percent likelihood that the fetal blood lead concentration may exceed 7.8 Ug dL in similarly exposed pregnant women. The calculated lead concentration is below the CDC and USEPA level of concern of 10 Ug dL. A greater exposure frequency a higher dust lead concentration or exposure to a highly soluble form of lead such as lead chloride or lead acetate may result in a calculated PbBfetal 0 95 that could potentially exceed 10 Ug dL. In practice blood lead concentrations could also be measured in women of child-bearing age to provide reassurance that they were not being overexposed. Although the preceding equation does not evaluate inhalation exposures to lead it could easily be modified to do so. The Agency for Toxic Substances and Diseases Registry ATSDR has summarized human inhalation studies of lead and determined biokinetic slope factors relating the air lead concentration to increases in blood lead. For example individuals exposed to lead concentrations in air ranging from 3.2 to 11 Ug m3 had average blood lead increases of 1.75 Ug dL for every Ug m3 lead in air. Individuals in the study reviewed by ATSDR were exposed for 23 h day for 18 weeks. Given that workers would not be exposed to the workplace atmosphere for 23 h day it would be reasonable to assume that only half the air breathed in a day was from the affected workplace i.e. a correction factor of 0.5 . If the above equation is modified to reflect exposure to lead in air at a concentration of 0.5 Ug m3 the equation would be revised as follows PbBf t 10 95 1 81-645 X 1300 Ug g X 0-4 Ug dL Ug day 0-05 Ug day 0-12 150 days year 9J - 365 days year 0-5 Ug m3 X 1-75 Ug dL Ug m3 0-5 150 days year 20 Ug dL 09 PbBfetai 0-95 8-2 Ug dL when inhalation exposure to lead is added to ingestion of lead 19.4 PETROLEUM HYDROCARBONS ASSESSING .