饮水型砷暴露人群改水前后尿砷甲基化代谢产物水平分析

目的探讨改水对饮水型砷暴露人群尿砷甲基化代谢的影响。方法采用整群抽样方法选取内蒙古自治区巴彦淖尔市饮水型地方性砷中毒病区居住年限≥10年的常住居民作为调查对象, 分别在2004(改水前)、2014(改水后4年)及2017年(改水后7年)采集调查对象尿样(n = 874、111、145), 并于2014、2017年对部分人群进行跟踪随访。采用高效液相色谱电感耦合等离子体质谱仪(HPLC-ICP-MS)检测尿中不同形态砷代谢产物[无机砷(iAs)、一甲基胂(MMA)、二甲基胂(DMA)], 计算总砷(tAs)含量、无机砷百分比(iAs%)、一甲基胂百分比(MMA%)、二甲基胂百分比(DMA%)、一甲基化率(PMI)、二甲基化率(SMI)、一甲基胂与二甲基胂比值(MMA/DMA)。对改水前后及改水后不同时间点砷暴露人群尿砷代谢产物含量及分布进行对比分析。结果与2004年比较, 2014年砷暴露人群尿中iAs、MMA、DMA、tAs、iAs%水平均较低(Z =-14.12、-12.79、-14.27、-14.21、-6.90, P均< 0.001), MMA%、DMA%、PMI水平均较高...     

高砷暴露致皮肤损伤人群尿砷代谢产物分析

目的 探讨高砷暴露致皮肤损伤人群尿砷代谢的特点.方法 应用氢化物发生.冷阱捕获.原子吸收分光光度法测定高砷暴露地Ⅸ(水砷浓度分别为0.21、0.24、0.36 mg/L)皮肤损伤组人群(77人)和未见皮肤损伤对照组人群(77人,性别、年龄1:1配比)尿中无机砷(iAs)、一甲基胂酸(MMA)和二甲基胂酸(DMA)含量.以iAs、MMA及DMA的总和表示总砷(tAs)水平;以iAs/tAs、MMMtAs和DMA/tAs分别计算iAs%、MMA%、DMA%;以(MMA+DMA)/tAs及DMM(MMA+DMA)分别计算一甲基化率(FMR)和二甲基化率(SMR)水平.结果 皮肤损伤组人群与对照组人群相比尿中各形态砷化合物及总砷含量差异无统计学意义(JD>0.05),而皮肤损伤组尿iAs%水平高于对照组,DMA%、FMR和SMR水平低于对照组差异均有统计学意义(P<0.05).皮肤损伤组人群中男性SMR水平显著低于女性,且尿中MMA%显著高于女性(P<0.05).结论 高砷暴露情况下,出现皮肤损伤症状的人群对砷的甲基化能力较低.

Abstract：

Objective To explore the characteristics of urine arsenic metabolism of people with skin lesion. Methods The levels of inorganic arsenic (iAs), monomethylated arsenic (MMA), dimethylated arsenic (DMA) in urine were detected with hydride generation-cold trap-atomic absorption spectroscopy among population exposed to higher levels of arsenide (0.24 ,0.36,0.21 mg/L), which consisted of skin lesion group(n=77) and non-skin lesion group (n=77,control group) in Apr.,2009 . Total arsenic (tAs) , iAs %, MMA%, DMA%, the first methylation ratio (FMR) and the secondary methylation ratio (SMR) were calculated as iAs + MMA+ DMA , iAs/tAs, MMA/tAs, DMA/tAs, (MMA + DMA)/ tAs and DMA/(MMA + DMA), respectively. Results No significant difference was observed in urinary concentrations of arsenic species and tAs between two groups (P>0.05), iAs% was much higher and the levels of FMR, SMR and DMA% were significantly lower in skin lesion group compared with the control (P<0.05). There were statistically significant differences in iAs% and SMR between males and females of the skin lesion group(P<0.05). Conclusion The arsenic methylation capacity of the persons with skin lesions is lower at high arsenic exposure.     

不同浓度饮水型砷暴露人群尿砷代谢产物的研究

目的 结合WHO推荐的饮水砷卫生标准(0.01 mg/L)和我国农村分散式供水采用的饮水砷卫生标准(0.05 mg/L),初步探讨不同浓度饮水砷暴露人群的砷代谢状况和甲基化水平.方法 于2008年10月选择山西高砷地区不同饮水砷浓度暴露的部分成年人为研究对象,高暴露组124人,饮水砷浓度≥0.05 mg/L;低暴露组154人,0.01 mg/L≤饮水砷浓度<0.05 mg/L;对照组70人,饮水砷浓度<0.01 mg/L.采用氢化物发生原子吸收分光光度法检测其尿中不同形态的砷代谢产物.结果 随着饮水砷暴露浓度的升高,尿中各种形态砷代谢产物以及总砷含量也逐渐增高(P<0.05) .在同一水砷浓度暴露水平下,高暴露组中女性DMA,TAs含量以及SMR水平显著高于男性(P<0.05);低暴露组和对照组iAs、MMA、DMA、TAs含量、FMR和SMR水平在不同性别间差异均无统计学意义(P>0.05).高暴露组中60岁～人群FMR水平显著高于18～39岁人群和40～49岁人群(P<0.05).而低暴露组与对照组内不同年龄段人群FMR和SMR水平均无显著差异(P>0.05).结论 成人在较高饮水砷暴露水平下,女性二甲基化能力高于男性,高年龄组显示甲基化能力增强.在低饮水砷暴露条件下,性别、年龄对机体甲基化能力未见明显影响.     

饮水型地方性砷中毒病区人群砷代谢模式影响因素分析

目的探讨饮水型地方性砷中毒(简称饮水型砷中毒)病区人群砷代谢模式及影响因素。方法 2004年12月, 采用整群抽样方法, 选取内蒙古自治区巴彦淖尔市饮水型砷中毒病区内砷中毒人群(砷中毒组)与健康人群(对照组)作为调查对象, 对其进行问卷调查。采用高效液相色谱-电感耦合等离子体质谱法检测调查对象家中饮用水砷含量, 尿砷及其代谢产物[三价砷(AsⅢ)、无机砷(iAs)、一甲基胂酸(五价, MMAV)、二甲基胂酸(五价, DMAV)、总砷(tAs)、无机砷百分比(iAs%)、一甲基胂酸百分比(MMA%)、二甲基胂酸百分比(DMA%)、一甲基化率(PMI)、二甲基化率(SMI)]水平;采用原子荧光光度计检测指甲砷和指甲硒水平。采用多元线性回归分析砷代谢模式的影响因素。结果共纳入调查对象536人, 其中砷中毒组155人、对照组381人, 水砷含量范围为0.0 ～ 825.7 μg/L。与对照组比较, 砷中毒组性别、文化程度、氟斑牙患病分布情况, 差异均无统计学意义(均P > 0.05);而年龄、婚姻状况、吸烟、饮酒、水砷含量分布情况, 差异均有统计学意义(均P < 0.05)。与对照...     

不同饮水砷暴露人群尿中的砷代谢物水平

目的 测定内蒙古高砷病区不同浓度饮水砷暴露人群尿中各种形态砷代谢物和总砷(total arsenic,TAs)含量.方法 于2004年10月运用横断面调查方法,随机抽取病区(A村:水砷浓度为240μg/L;B村:水砷浓度为160μg/L;C村:水砷浓度为90 μg/L,D村即对照组:水砷浓度＜5μg/L)人群尿样,采用氢化物发生原子吸收分光光度法检测尿中各形态砷代谢物和TAs含量.结果 随着饮水砷暴露浓度的增高,人群尿中无机砷(inorganic arsenic,iAs)、甲基砷(monomethylarsine,MMA)、二甲基砷(dimethylarsine,DMA)和TAs含量均增高(P＜0.05).暴露于相同水砷浓度的条件下,尿中iAs、MMA、DMA和TAs含量以及一甲基化率(primary methylation index,PMI)和二甲基化率(secondary methylation index,SMI)在不同性别间未见统计学差异(P＞0.05).各暴露组成人和儿童尿中PMI和SMI水平分别低于对照组成人和儿童(P＜0.05);240μg/L组成人尿中PMI和SMI水平显著低于90和160μg/L暴露组(P＜0.05);240μg/L组儿童尿中PMI水平低于160μg/L组儿童(P＜0.05),各暴露组儿童尿中SMI水平顺序为160μg/L组＞90μg/L组＞240μg/L组(P＜0.05);各暴露组中儿童尿中SMI水平均高于相应的成人(P＜0.05).结论 饮水中高砷暴露可能降低人群对砷的甲基化能力.相同饮水砷暴露水平,男女对砷的甲基化能力无差别,儿童二甲基化能力高于成人.低水平砷暴露可能诱导儿童对砷的二甲基化能力.     

渔村与砷暴露地区居民尿砷代谢产物检测比较

目的 测定渔村居民和饮水型砷暴露地区人群尿中各种形态砷和尿总砷(TAs).方法 选取饮水型砷暴露地区[口肯板村水砷浓度为0.16 mg/L;乃莫板村水砷浓度为0.09 mg/L;塔布塞村(对照组)饮用水砷浓度<0.01 mg/L]和渔村居民.采用氢化物发生原子吸收分光光度法检测尿中各形态砷代谢物和TAs含量.结果 TAs含量渔村居民明显低于0.16 mg/L暴露组,高于对照组(P<0.05),与0.09 mg/L暴露组差异无统计学意义;渔村居民尿无机砷(iAs)含量明显低于0.09和0.16 mg/L暴露组(P<0.05);尿甲基砷(MMA)含量同尿二甲基砷(DMA)含量,各组之间差异均有统计学意义(P<0.05);渔村居民尿iAs百分比明显低于对照组、0.09和0.16 mg/L暴露组(P<0.05);尿MMA百分比同尿iAs百分比;各组尿DMA百分比差异均有统计学意义(P<0.05);渔村居民特异性的检测出尿三甲胺(TMA).结论 人群尿总砷水平受食用海产品等因素影响,不能单独作为砷暴露指标,应使用分析性方法来区分砷复合物中无机砷和有机砷的代谢产物.     

2012年平罗县饮水型地方性砷中毒调查

为了解平罗县饮水型地方性砷中毒情况,于2012年对3个被列为国家级监测点的病区村(A、B、C)进行砷中毒患病调查;每村采集30名以往暴露过高砷水的成人(年龄在15～78岁,不足30人时,可补充检测疑似患者、正常人)尿样;并于枯水期采集1份末梢水水样,按照相应国标监测尿砷、水砷含量. 三个监测点由2个改水工程覆盖(B村2009年3月改水,A、C村2008年5月改水),改水工程运转正常且3个村水砷含量(＜0.01～0.024 mg/L)均合格.共检查46人,未发现砷中毒患者;仅在C村检出4例可疑病例,占11.43％(4/35).尿砷含量在0.001～0.055 mg/L,中位数为0.008 mg/L,几何均值为0.009 mg/L.见表1.     

江苏省高砷地区尿砷、发砷含量调查

目的：为了解江苏省高砷区居民砷中毒情况,对其尿砷、发砷含量进行测定,以协助地方性砷中毒临床诊断。方法：选择苏北地区高砷村和对照村,采集30岁以上成人尿样和发样,测定其砷含量。结果：高砷村尿砷、发砷含量范围分别在0.008～0.320mg/L和0.068～4.158mg/kg之间,对照村分别在0.004～0.127 mg/L和0.011～0.568mg/kg之间,高砷村明显高于对照村（P〈0.01）。结论：通过尿砷和发砷含量的测定,可协助地方性砷中毒的临床诊断。     

陕南燃煤型砷中毒典型村居民的发砷含量特征

目的研究陕南燃煤型地方性砷中毒病区的高砷石煤暴露人群发砷含量与年龄、性别、病情的关系。方法采集病区高砷暴露居民的发样90份,对照村居民的发样14份。用电感耦合等离子体质谱(ICP-MS)测定发砷。结果陕南砷暴露村居民发砷含量显著高于对照村,同时显著高于砷中毒病情更加严重的贵州省兴仁县长青镇,经比较差异均有统计学意义(P<0.05)。高砷暴露人群内部发砷含量随着年龄增加和砷中毒病情加重而增加,符合慢性砷暴露的特征,男性和女性的发砷差异不显著。41名未出现临床体征的居民发砷含量高达7.83 mg/kg,与轻度、中度中毒患者的发砷含量差异无统计学意义(P>0.05),表明在皮肤损伤症状出现之前,砷已经在人体内蓄积并达到有害程度,可能处于亚临床阶段。结论陕南燃煤型砷中毒病区暴露人群具有高砷蓄积特征;无临床体征的高砷暴露人群可能处于亚临床阶段,提示在地方性砷中毒的诊断标准中,应重视发砷值而不能仅注重临床症状和体征。     

人体发、甲、尿中砷含量的调查

砷对人体是一种蓄积性毒物,危害人体健康可引起慢性砷中毒。为了探讨砷在人体的蓄积部位,危害人群健康的诊断依据,我们选择三个污染区和一个非污染区进行了753人份的头发、482人份的指(趾)甲、507人份的尿样砷含量的抽样调查,结果:污染区的头发、指(趾)甲、尿砷含量分别为7.63、14.53、0.20ppm,非污染区分别为0.63、2.15、0.17ppm。除尿砷外不同区域有非常显著性差异。 过去习惯采用尿砷作为诊断慢性砷中毒的常用指标,本次调查表明污染区砷暴露人群和对照区人群尿砷无差异,提示砷进入人体达到一定浓度后,肾脏就不一定再是排砷的主要途径了;头发、指(趾)甲是砷蓄积的重要部位,因此头发、指(趾)甲砷比尿砷对慢性砷中毒的诊断更有意义。     

新疆地方性砷中毒地区居民改水前后发砷和尿砷的变化

目的 研究砷在人体内蓄积与排泄的情况,评价改水对地方性砷中毒的影响.方法 于2001年追踪调查新疆奎屯高砷区改水前后35人(男性21人,女性14人)和对照区31人尿砷含量(男性14人,女性17人).另外选择奎屯高砷区44人(男性24人,女性20人),追踪其中21人(男性14人,女性7人)发砷变化;并测定了对照区32人(男性16人,女性16人)发砷含量.尿、发中砷含量的测定均采用二乙氨基二硫代甲酸银比色法.结果 改水前男性、女性的尿砷、发砷水平均高于改水后,经秩和检验,差异有统计学意义(P＜0.05).改水前7人发砷超标,超标率为33.33%;改水后1人发砷超标,超标率为4.76%.改水后高砷区人群尿砷水平高于对照区,高砷区女性尿砷水平高于对照区,高砷区男性、女性的发砷水平均高于对照区,经秩和检验,差异均有统计学意义(P＜0.01).结论 改水可减少砷在人体内蓄积,降低高砷地区地方性砷中毒的流行.     

Association between chronic exposure to arsenic and slow nerve conduction velocity among adolescents in Taiwan

The association between chronic exposure to arsenic and peripheral neuropathy has been controversial in previous studies, which may be due to the influence of factors, such as age, gender, chronic diseases, occupational injuries, and arsenic exposure. To clarify the question of this association, a cross-sectional study was designed. In total, 130 junior high school students aged 12-14 years were included and examined for the motor and sensory nerve conduction velocity of peripheral nerves in their right-upper and lower limbs. Concentrations of arsenic in well-water and history of drinking well-water were retrieved from a baseline database created in 1991. After adjustment for gender and height, a significant odds ratio of 2.9 (95% confidence interval [CI] 1.1-7.5) was observed for the development of slow nerve conduction velocity of the sural sensory action potential (SAP) among the study subjects with a cumulative arsenic dosage of>100.0 mg. In addition, a borderline statistical significance with odds ratio of 7.8 (95% CI 1.001-69.5) for the development of slow nerve conduction velocity of sural SAP was also observed among the study subjects who drank well-water containing arsenic concentrations of >50.0 microg/L and with a cumulative arsenic dosage of >100.0 mg. The study found that chronic exposure to arsenic might induce peripheral neuropathy. It also found that the slowing of the nerve conduction velocity of sural SAP might be an early marker of chronic arsenic neuropathy.     

中国9个长寿地区65岁及以上人群血砷水平与高尿酸血症的关联研究

目的分析65岁及以上人群血砷水平与高尿酸血症的关联。方法研究对象来自2017-2018年在我国9个长寿地区开展的“老年健康生物标志物队列研究”,共纳入2438名血砷和血尿酸数据完整的65岁及以上研究对象。通过问卷调查和体格检查,收集调查对象的人口学特征、生活方式及健康状况等信息;同时采集调查对象的静脉血以检测血砷、血尿酸等水平。根据血砷水平的三分位数将对象分为砷低水平组、砷中水平组和砷高水平组,采用logistic回归模型分析血砷水平和高尿酸血症的关联。结果2438名研究对象年龄为(84.57±11.41)岁,其中男性1172名(48.07%),≥80岁者1525名(62.55%),高尿酸血症的检出率为17.23%(420例)。砷低、中、高水平组的高尿酸血症检出率分别为11.77%、19.25%和20.62%(P<0.001)。多因素logistic回归模型分析结果显示,调整相关混杂因素后,与砷低水平组相比,砷中、高水平组高尿酸血症检出风险较高[OR(95%CI)值分别为1.57(1.12~2.23)和2.08(1.46~2.99)]。与女性相比,男性老年人血砷水平与高尿酸血症的关联更为显著(P_交互值<0.05)。结论中国9个长寿地区65岁及以上老年人群血砷水平与高尿酸血症的检出风险存在关联。     

Arsenic groundwater contamination in Middle Ganga Plain,Bihar, India: a future danger?

The pandemic of arsenic poisoning due to contaminated groundwater in West Bengal, India, and all of Bangladesh has been thought to be limited to the Ganges Delta (the Lower Ganga Plain), despite early survey reports of arsenic contamination in groundwater in the Union Territory of Chandigarh and its surroundings in the northwestern Upper Ganga Plain and recent findings in the Terai area of Nepal. Anecdotal reports of arsenical skin lesions in villagers led us to evaluate arsenic exposure and sequelae in the Semria Ojha Patti village in the Middle Ganga Plain, Bihar, where tube wells replaced dug wells about 20 years ago. Analyses of the arsenic content of 206 tube wells (95% of the total) showed that 56.8% exceeded arsenic concentrations of 50 micro g/L, with 19.9% > 300 micro g/L, the concentration predicting overt arsenical skin lesions. On medical examination of a self-selected sample of 550 (390 adults and 160 children), 13% of the adults and 6.3% of the children had typical skin lesions, an unusually high involvement for children, except in extreme exposures combined with malnutrition. The urine, hair, and nail concentrations of arsenic correlated significantly (r = 0.72-0.77) with drinking water arsenic concentrations up to 1,654 micro g/L. On neurologic examination, arsenic-typical neuropathy was diagnosed in 63% of the adults, a prevalence previously seen only in severe, subacute exposures. We also observed an apparent increase in fetal loss and premature delivery in the women with the highest concentrations of arsenic in their drinking water. The possibility of contaminated groundwater at other sites in the Middle and Upper Ganga Plain merits investigation.     

Levels of arsenic in drinking-water and cutaneous lesions in Inner Mongolia

The most common health effects from drinking-water containing dissolved arsenic are skin abnormalities and lesions that are typically diagnosed as keratosis and pigment disorder. It was previously reported that the prevalence of cutaneous lesions was about 44% in arsenic-affected villages. However, there has been little research on the relationship between levels of arsenic in drinking-water and cutaneous lesions in Inner Mongolia. One study examined the association between the prevalence of keratosis and levels of arsenic exposure and the relationship between pigment disorder and levels of arsenic exposure among villagers aged 18 years or older in the arsenic-affected village of Hetao Plain in Inner Mongolia, PR China. The study included 227 participants who were affected by cutaneous lesions and 221 participants who were not affected by cutaneous lesions diagnosed in 1996 and 1998. Well-water drunk by the participants was collected to analyze arsenic content. Adjusting for age, sex, and smoking, logistic regression was applied to calculate the risks that arsenic in drinking-water will lead to cutaneous lesions. The results from the logistic regression showed that, with the increase of arsenic concentration in water, the risk of pigment disorder also increased (odds ratio [OR]=5.25, 95% confidence interval [CI] 1.32-83.24 for 50-199 microg/L; OR=10.97, 95% CI 1.50-79.95 for 200-499 [microg/L; OR=10.00, 95% CI 1.39-71.77 for > or = 500 microg/L (p=0.000), but the association between risk of keratosis and levels of arsenic was not significant (p=0.346). The findings suggest that keratosis is an early feature of arsenic poisoning, and the development of pigment disorder depends on higher doses of arsenic intake rather than keratosis. Further studies are needed to confirm that cutaneous lesions and other adverse health effects occur at low levels of arsenic exposure.     

慢性鼻-鼻窦炎患者嗅觉障碍患病情况及其影响因素

目的 分析慢性鼻-鼻窦炎(CRS)伴嗅觉障碍发生情况及其影响因素,为制定相应干预措施提供依据。方法 以2018年辽宁省阜新市某医院就诊的成年CRS患者为研究对象,进行问卷调查、T&T嗅觉功能检查、血清总免疫球蛋白E(IgE)水平检测及鼻内镜Lund-Kennedy评分。采用单、多因素分析方法对CRS伴嗅觉障碍发生影响因素进行分析。结果 本研究共对340例CRS患者进行研究,平均年龄(45.73 ± 10.14)岁,以41~64岁为主,占45.88%,男性占65.00%,女性占35.00%。CRS伴嗅觉障碍患病率为44.12%。多因素分析结果显示,血清总IgE水平阳性(OR=1.526)、Lund-Kennedy评分≥2分(OR=2.813)、前期鼻内镜手术史(OR=1.504)、哮喘史(OR=1.870)、鼻息肉(OR=2.139)、阿司匹林不耐受(OR=1.317)是CRS伴嗅觉障碍的危险因素。结论 辽宁省阜新市CRS伴嗅觉障碍患病率处于高水平,其危险因素有哮喘史、前期鼻内镜手术史、鼻息肉、阿司匹林不耐受、血清总IgE水平阳性、Lund-Kennedy评分≥2分等,建议采取相应干预措施降低CRS伴嗅觉障碍患病率。     

青岛市市售海产品砷污染状况及无机砷暴露风险评估

目的 通过分析青岛市市售海产品中总砷及无机砷含量水平以及居民的海产品膳食摄入量，对本市市售海产品中的砷污染状况及人群无机砷暴露风险进行评估。方法 在全市采集215份海产品样品，采用氢化物发生原子荧光光谱法、液相色谱-原子荧光光谱法分别测得总砷及无机砷含量，并根据青岛市居民海产品平均摄入量，利用靶器官危害系数(THQ)对青岛市居民海产品中无机砷食用健康风险进行评估。结果 总砷含量由高到低依次为甲壳类、贝类、鱼类，无机砷含量由高到低依次为贝类、甲壳类、鱼类。2 007名青岛市居民的膳食调查结果显示，居民每日海产品摄入量均值为1.68 g/kg·bw。海产品中，贝类是居民摄入无机砷的主要来源。45～59岁男性组中，由于摄入较多的海产品，摄入水平较高的居民THQ值＞1，可认为存在一定的健康风险。结论 青岛市居民海产品的食用健康风险在安全范围内，但对于45～59岁年龄段中海产品摄入较高的男性居民而言，存在健康风险，应注意重点防范。     

Association between nutritional status and arsenicosis due to chronic arsenic exposure in Bangladesh

The role of nutritional factors in arsenic metabolism and toxicity is not clear. Provision of certain low protein diets resulted in decreased excretion of DMA and increased tissue retention of arsenic in experimental studies. This paper reports a prevalence comparison study conducted in Bangladesh to assess the nutritional status among the chronic arsenic exposed and unexposed population. 138 exposed individuals diagnosed as arsenicosis patients were selected from three known arsenic endemic villages of Bangladesh and age, sex matched 144 unexposed subjects were randomly selected from three arsenic free villages. The mean arsenic concentration in drinking water for the exposed and unexposed population was 641.15 and 13.5 microg L(-1) respectively. Body Mass Index was found to be lower than 18.5, the cut off point for malnutrition, in 57 (41.31%) out of 138 exposed arsenicosis cases and 31 (21.53%) out of 144 unexposed individuals. The crude prevalence ratio (or risk) was 1.92 (95% CI = 1.33-2.78) for poor nutritional status among the arsenicosis cases compared to the unexposed population. The findings of this study add to the evidence that poor nutritional status may increase an individual's susceptibility to chronic arsenic toxicity, or alternatively that arsenicosis may contribute to poor nutritional status.     

Arsenic concentrations in prediagnostic toenails and the risk of bladder cancer in a cohort study of male smokers

At high concentrations, inorganic arsenic can cause bladder cancer in humans. However, it is unclear whether low exposure to inorganic arsenic in drinking water (<100 microg/liter) is related to bladder cancer risk. No study has been known to use biomarkers to assess the relation between individual arsenic exposure and bladder cancer risk. Toenail samples provide an integrated measure of internal arsenic exposure and reflect long-term exposure. The authors examined the relation between toenail arsenic levels and bladder cancer risk among participants in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study, a cohort of Finnish male smokers aged 50-69 years. Data for 280 incident bladder cancer cases, identified between baseline (1985-1988) and April 1999, were available for analysis. One control was matched to each case on the basis of age, toenail collection date, intervention group, and smoking duration. Arsenic levels in toenail samples were determined by using neutron activation analysis. Logistic regression analyses were performed to estimate odds ratios. Arsenic toenail concentrations in this Finnish study were similar to those reported in US studies (range: 0.02-17.5 microg/g). The authors observed no association between inorganic arsenic concentration and bladder cancer risk (odds ratio = 1.13, 95% confidence interval: 0.70, 1.81 for the highest vs. lowest quartile). These findings suggest that low-level arsenic exposure is unlikely to explain a substantial excess risk of bladder cancer.     

Arsenic in drinking water in the Los Altos de Jalisco region of Mexico.

OBJECTIVE: To establish the degree of contamination by arsenic in drinking water in the Los Altos de Jalisco (LAJ) region of west-central Mexico, and to estimate the levels of exposure that residents of the area face. METHODS: Total arsenic concentration (the sum of all arsenic forms, organic and inorganic) was determined for 129 public water wells in 17 municipal capitals (cabeceras municipales) of the LAJ region, using inductively coupled plasma-optical emission spectroscopy. For most of the wells, water samples were taken in both November 2002 and October 2003. The levels of exposure to arsenic were estimated for babies (10 kg), children (20 kg), and adults (70 kg). RESULTS: Mean concentrations of arsenic higher than the Mexican national guideline value of 25 micro g/L were found in 44 (34%) of the 129 wells. The mean concentration of total arsenic for the 129 wells ranged from 14.7 micro g/L to 101.9 micro g/L. The highest concentrations were found in well water samples collected in the cities of Mexticacán (262.9 micro g/L), Teocaltiche (157.7 micro g/L), and San Juan de los Lagos (113.8 micro g/L). Considering the global mean concentration for all the wells in each of the 17 cities, the mean concentration of arsenic exceeded the Mexican guideline value in 7 of the cities. However, the global mean concentration in all 17 cities was higher than the World Health Organization guideline value of 10 micro g/L for arsenic. The range of the estimated exposure doses to arsenic in drinking water was 1.1-7.6 micro g/kg/d for babies, 0.7-5.1 micro g/kg/d for children, and 0.4-2.7 micro g/kg/d for adults. CONCLUSIONS: At the exposure doses estimated in the LAJ region, the potential health effects from chronic arsenic ingestion include skin diseases, gastrointestinal effects, neurological damage, cardiovascular problems, and hematological effects. While all the residents may not be affected, an important fraction of the total population of the LAJ region is under potential health risk due to the ingestion of high levels of arsenic. Epidemiological studies to determine the arsenic levels in the blood, hair, and nails of humans should be conducted in the LAJ region to help assess the relationship between the prevalence of health problems and the chronic ingestion of arsenic.