Environmental exposure to benzene: evaluation of urinary S-PMA and polymorphism (CYP2E1-1293G>C and NQO1 609C>T) in Campos Elíseos residents, Duque de Caxias, Rio de Janeiro State, Brazil

Benzene is one of the most important substances for assessment, due to its significant use, the environmental contamination resulting from its emission and the effects on human health. It is classified by the International Agency for Research on Cancer (IARC) as a known carcinogen to humans (group 1) and associated with the development of leukemia. In general, the population is exposed to this substance by inhaling contaminated air, which varies according to the location and intensity of its potential sources. The petrochemical industry is one of the most important sources of this compound. The municipality of Duque de Caxias, specifically the Campos Elíseos district, in Rio de Janeiro State, Brazil, houses the Industrial Complex of Campos Elíseos (PICE), a grouping of over 25 industries, which includes the second largest oil refinery in Brazil. Environmental contamination from the PICE has been recognized, but there is a lack of studies concerning its impact on the health of the surrounding population. S-phenylmercapturic acid (S-PMA) concentrations ranging from 0.80 to 8.01μg.g-1 creatinine were observed in the local population, apparently related to hematological changes also observed in exposed population. The quantifiable presence of urinary S-PMA from the benzene metabolism is associated with the fact that 60% of the participants present specific hematological changes, which may be due to the environmental benzene exposure. The allele and genotype frequencies of the CYP2E1 and NQO1 enzymes observed in the study population were similar to those reported in other studies. The presence of the variant allele in the NQO1 genotype may be a risk factor for the observed hematological changes.苯（Benzene）是环境健康评估中最为重要的物质之一，这源于其广泛的应用场景、排放所引发的环境污染，以及其对人类健康造成的诸多危害。国际癌症研究机构（International Agency for Research on Cancer, IARC）将苯归类为人类确认致癌物（第1组），且明确其与白血病的发病存在关联。通常情况下，人群可通过吸入受污染的空气接触苯，暴露水平会随潜在污染源的位置与强度差异而变化。石化工业是该化合物的核心污染源之一。巴西里约热内卢州杜克德卡西亚斯市的坎波斯埃利塞乌斯街区，坐落着坎波斯埃利塞乌斯工业综合体（PICE），该综合体汇聚了超过25家工业企业，其中包含巴西第二大炼油厂。尽管PICE造成的环境污染已被证实，但针对其对周边居民健康影响的相关研究仍较为匮乏。研究在当地居民尿液中检测到浓度介于0.80~8.01μg·g⁻¹肌酐的S-苯基巯基尿酸（S-phenylmercapturic acid, S-PMA），该代谢产物与暴露人群中观察到的血液学改变存在显著相关性。尿液中可检测到源于苯代谢的S-PMA，这一现象与60%的研究参与者出现特异性血液学改变相关，该改变可能由环境苯暴露所致。本研究人群中CYP2E1与NQO1酶的等位基因及基因型频率，与其他已发表研究的报道结果基本一致。NQO1基因型携带变异等位基因，可能是上述血液学改变的风险因素。