劉俊曉,王孟麗,王戰(zhàn)會(huì)
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鉛污染區(qū)學(xué)齡前兒童血鉛暴露水平及其對(duì)兒童體格發(fā)育的影響
劉俊曉,王孟麗,王戰(zhàn)會(huì)
摘要:目的了解鉛污染區(qū)學(xué)齡前兒童的血鉛暴露水平,評(píng)估血鉛暴露對(duì)兒童生長發(fā)育的影響。方法對(duì)鉛污染區(qū)153例和對(duì)照地區(qū)150例學(xué)齡前兒童(3~6歲),進(jìn)行血鉛水平檢測,同時(shí)進(jìn)行身高、體重、頭圍、胸圍等指標(biāo)測量分析。結(jié)果暴露組兒童血鉛水平(14.42±6.92 )μg·dL-1高于對(duì)照組(8.69±4.33) μg·dL-1,差異具有統(tǒng)計(jì)學(xué)意義(P<0.05);暴露組兒童血鉛值≥10 μg·dL-1者占69.9%(107/153);高鉛負(fù)荷(≥10 μg·dL-1)和低鉛負(fù)荷(<10 μg·dL-1)兒童比較,6歲兒童的頭圍(50.04±1.29)cm vs. (48.71±1.66) cm 差異有統(tǒng)計(jì)學(xué)意義(P<0.01),和胸圍(52.87±2.49)cm vs (51.70 ± 3.35)cm差異有統(tǒng)計(jì)學(xué)意義(P<0.05);兒童的身高、年齡與血鉛水平呈負(fù)相關(guān)。結(jié)論鉛污染區(qū)學(xué)齡前兒童血鉛負(fù)荷增高,高鉛負(fù)荷可能影響兒童的生長發(fā)育;要預(yù)防鉛污染區(qū)的兒童鉛污染,保護(hù)兒童健康。
關(guān)鍵詞:兒童;鉛污染;體格發(fā)育
作者單位:鄭州大學(xué)附屬洛陽中心醫(yī)院,河南洛陽 471009
鉛廣泛存在于生產(chǎn)和生活環(huán)境中,主要通過呼吸道和消化道等途徑進(jìn)入人體,是危害人體健康的有毒重金屬之一。鉛可造成機(jī)體神經(jīng)、血液、骨骼、腎臟等多系統(tǒng)及功能的損害,尤其是出生前和兒童時(shí)期的鉛暴露,能影響兒童的神經(jīng)系統(tǒng)發(fā)育、行為認(rèn)知和智力發(fā)育等[1]。鉛還能通過影響鈣、鐵、鋅等的吸收,抑制激素的合成和利用,從而影響兒童的體格發(fā)育,使兒童身體發(fā)育遲緩,女孩青春期延遲等[2]。本研究通過對(duì)比鉛污染區(qū)學(xué)齡前兒童的血鉛水平和健康發(fā)育情況,評(píng)估鉛污染區(qū)兒童的血鉛暴露水平及其對(duì)體格發(fā)育的影響。
1材料與方法
1.1研究對(duì)象暴露組為某電子垃圾拆解集散地出生并長期居住的年齡3~6歲學(xué)齡前兒童153例(男童89例,女童64例);同時(shí),對(duì)照組為鄰鎮(zhèn)(從事內(nèi)衣生產(chǎn))同年齡段兒童150例(男童88例,女童62例)。取得家長知情同意后,對(duì)兒童進(jìn)行靜脈采血和體格檢查。
1.2標(biāo)本采集采集兒童肘部靜脈血,采血前,依次用5%洗潔凈棉球清潔,體積分?jǐn)?shù)2%的EDTA棉球反復(fù)擦拭,75%酒精棉球常規(guī)消毒后,采集抗凝靜脈血2 mL,充分混勻,-20℃冰箱保存。
1.3體格發(fā)育指標(biāo)測量測量指標(biāo)包括:身高、體質(zhì)量、頭圍和胸圍。所用測量儀器和軟尺均事前經(jīng)計(jì)量校準(zhǔn),測量員接受統(tǒng)一培訓(xùn)。使用落地式身高體質(zhì)量計(jì),進(jìn)行身高和體質(zhì)量測量,受檢兒童需空腹、排尿、脫鞋后進(jìn)行;使用軟尺測量頭圍和胸圍 ,取呼氣和吸氣時(shí)數(shù)值的平均值,讀數(shù)均精確至小數(shù)點(diǎn)后一位。
1.4檢測儀器及工作條件采用日本島津AA-660型原子吸收分光光度計(jì)進(jìn)行血鉛的檢測。波長283.30 nm,狹寬1.00 nm,工作電流10 mA,水壓 0.5 kg·cm-2,氣壓2.5 kg·cm-2,10 μL進(jìn)樣,BGC-D2類型測量峰高,加熱程序:150 ℃干燥30 s,350 ℃灰化40 s,1 400 ℃原子化4 s,2 000 ℃清除2 s,冷卻20 s。采用血鉛標(biāo)準(zhǔn)參照物進(jìn)行質(zhì)量控制。
2結(jié)果
2.1兒童血鉛水平分析
暴露組兒童血鉛為偏態(tài)分布,對(duì)照組血鉛服從正態(tài)分布,結(jié)果顯示,暴露組血鉛水平高于對(duì)照組,差異具有統(tǒng)計(jì)學(xué)意義(P<0.01);暴露組兒童血鉛值≥10 μg·dL-1者有107人,占69.9%;本研究中對(duì)照組兒童血鉛中位數(shù)具有較高水平為8.24 μg·dL-1,因此對(duì)照組為弱陰性對(duì)照,見表1。
μg·dL-1
注:暴露組與對(duì)照組血鉛相比:①Z=-8.001,P<0.01;②χ2=33.68,P<0.01。
不同年齡組兒童血鉛水平見表2,結(jié)果顯示,暴露組和對(duì)照組中均為3歲兒童血鉛中位數(shù)最高,隨著年齡的增高血鉛中位數(shù)值下降,暴露組與對(duì)照組間,各年齡段血鉛差異比較,均有統(tǒng)計(jì)學(xué)意義(均為P<0.01)。
μg·dL-1
注:與同年齡段比:①Z=-2.25,P<0.01;②Z=-3.16,P<0.01;③Z=3.65,P<0.01;④Z=4.01,P<0.01。
暴露組男童和女童的血鉛分別與對(duì)照組間比較,差異均有統(tǒng)計(jì)學(xué)意義(均為P<0.05),暴露組和對(duì)照組的男、女童間血鉛水平分別比較,差異均無統(tǒng)計(jì)學(xué)意義(均為P>0.05),見表3。
μg·dL-1
注:與對(duì)照組比較:①Z=-5.001,P<0.01;②Z=-4.23,P<0.01。
2.2兒童鉛暴露水平與體格發(fā)育指標(biāo)的影響
按照2006年2月我國衛(wèi)生部有關(guān)兒童血鉛水平判斷標(biāo)準(zhǔn)相關(guān)公報(bào)內(nèi)容[3],本研究中將兒童血鉛值≥10 μg·dL-1標(biāo)識(shí)為高血鉛負(fù)荷狀態(tài)。以暴露組和對(duì)照組所有兒童為研究對(duì)象,比較高鉛負(fù)荷(≥10 μg·dL-1)和低鉛負(fù)荷(<10 μg·dL-1)對(duì)兒童各項(xiàng)體格發(fā)育指標(biāo)的影響。高鉛負(fù)荷和低鉛負(fù)荷兩組比較,結(jié)果顯示,不同年齡組中,6歲兒童的頭圍(50.04±1.29 ) cm vs (48.71±1.66) cm,差異有統(tǒng)計(jì)學(xué)意義(t=3.143,P=0.003),和胸圍(52.87±2.49) cm vs (51.70 ± 3.35) cm,差異有統(tǒng)計(jì)學(xué)意義(t=-2.011,P<0.05);高鉛負(fù)荷的女童胸圍低于低鉛負(fù)荷女童(49.23±2.27) cm vs (50.31 ± 3.22) cm,差異有統(tǒng)計(jì)學(xué)意義(t=-1.870,P<0.05)。
以兒童血鉛為應(yīng)變量,將兒童的體格發(fā)育、年齡等指標(biāo)作為考察因素,經(jīng)Spearman相關(guān)分析,兒童的身高與血鉛水平呈負(fù)相關(guān)(rs=-0.168,P=0.004),兒童的年齡與血鉛水平也呈負(fù)相關(guān)(rs=-0.162,P=0.008)。
3討論
以前認(rèn)為血鉛值低于10 μg·dL-1是兒童鉛負(fù)荷水平的安全范圍[3]。但近年來研究表明,兒童血鉛的安全標(biāo)準(zhǔn)受到質(zhì)疑,低于10 μg·dL-1水平的鉛負(fù)荷也可損害兒童的智力發(fā)育,鉛的毒性損害幾乎沒有下限值[4]。研究發(fā)現(xiàn),兒童低水平的鉛暴露就會(huì)對(duì)其神經(jīng)認(rèn)知功能和發(fā)育有顯著的負(fù)面影響[5]。本研究中兒童的身高與血鉛水平呈負(fù)相關(guān),高鉛負(fù)荷影響兒童的生長發(fā)育,使身高降低。高鉛負(fù)荷的6歲兒童的頭圍和胸圍,與低鉛負(fù)荷兒童比較,差異均有統(tǒng)計(jì)學(xué)意義;高鉛負(fù)荷的女童的胸圍小于低鉛負(fù)荷兒童,差異有統(tǒng)計(jì)學(xué)意義,這表明了高鉛負(fù)荷可能影響兒童的生長發(fā)育。本研究中暴露組兒童長期處于鉛污染環(huán)境,并導(dǎo)致鉛在體內(nèi)不斷蓄積,由于鉛污染的持久性,提示該地區(qū)鉛污染的嚴(yán)重性,將導(dǎo)致當(dāng)?shù)貎和霈F(xiàn)健康問題,應(yīng)引起當(dāng)?shù)刈銐虻闹匾?,需要進(jìn)一步的研究證實(shí)鉛污染對(duì)兒童健康發(fā)育的影響,并做好相應(yīng)的防治工作。
鉛作為一種多系統(tǒng)毒物,其毒性作用有顯著的年齡差異,因兒童處于生長發(fā)育期的生理特點(diǎn),低齡兒童對(duì)鉛的毒性作用更為易感和脆弱[6],本研究顯示低齡兒童中3歲兒童血鉛值最高,并且兒童的年齡與血鉛水平呈負(fù)相關(guān),也驗(yàn)證了此結(jié)論。本研究1~3歲為兒童血鉛高峰年齡段與美國第3次全國健康營養(yǎng)調(diào)查以及國內(nèi)一些城市兒童血鉛普查的結(jié)果基本一致[7-8]。而且,兒童的血鉛水平無明顯性別差異,此結(jié)果與Huo等報(bào)道相同[9]??傊?,本研究顯示鉛污染區(qū)學(xué)齡前兒童中3歲兒童血鉛值最高,并且兒童的身高、年齡與血鉛水平呈負(fù)相關(guān),預(yù)防兒童鉛污染,保護(hù)兒童健康,勢在必行。
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Association Between Blood Lead Levels in Children and Their Physical Development in a Lead-Contaminated Area
LIU Jun-xiao, WANG Meng-li, WANG Zhan-hui
(Luoyang Central Hospital Affiliated to Zhengzhou University,Luoyang 471009,China)
Abstract:ObjectiveTo investigate the children’s blood lead level in a lead-contaminated area and evaluate the effects of lead contamination on children’s health. MethodsThe health status of 153 children aged six years and lived in a lead-contaminated area and that of 150 children in normal area as a control group were observed. The blood lead level were determined by graphite atomizer absorption spectrophotometer. The height, weight, chest measurement, and head circumference of physical development survey was also performedin the two groups. ResultsChildren living in lead-contaminated area had significantly higher blood lead levels than that of control group (14.42±6.92)μg·dL-1vs (8.69±4.33) μg·dL-1(P<0.05). In lead-contaminated area 69.9% of children (107/153) blood lead levels had greater than or equal to 10 μg·dL-1. Chlidren’s head circumferences and chest circumferences of 6-year-old with blood lead levels ≥10 μg·dL-1was significantly higher than that in blood lead levels <10 μg·dL-1[head circumferences: (50.04±1.29)cm vs (48.71±1.66) cm(P<0.05); chest circumferences: (52.87±2.49)cm vs (51.70 ± 3.35) cm(P<0.05)]. Chlidren’s height and age were negative correlation to children’s blood lead levels. ConclusionThe blood lead level was significantly high in the lead-contaminated area children, which has threatened the health of children in lead-contaminated area,and the measures should be made to reduce lead pollution and protect the children health.
Key words:children;lead contaminated;physical development
通信作者:王戰(zhàn)會(huì),男,主任醫(yī)師,E-mail:zhanhuiwangxyjt@163.com
作者簡介:劉俊曉(1978-),女,河南洛陽人,博士,主管技師,從事環(huán)境毒理與人體健康研究工作。
收稿日期:2015-11-26
基金項(xiàng)目:洛陽市科技發(fā)展計(jì)劃項(xiàng)目(1301069A-3)
中圖分類號(hào):R179
文獻(xiàn)標(biāo)志碼:B
DOI:10.15926/j.cnki.issn1672-688x.2016.01.022
文章編號(hào):1672-688X(2016)01-0060-03