趙富強(qiáng),高 會(huì),李瑞婧,金帥辰,張海波,李十盛,3,張克玉,3,束 芹,3,那廣水,3,4*

環(huán)渤海區(qū)域典型河流下游水體中抗生素賦存狀況及風(fēng)險(xiǎn)評(píng)估

趙富強(qiáng)1,2,高 會(huì)1,李瑞婧1,金帥辰1,張海波1,李十盛1,3,張克玉1,3,束 芹1,3,那廣水1,2,3,4*

(1.國(guó)家海洋環(huán)境監(jiān)測(cè)中心,遼寧 大連 116023；2.大連海洋大學(xué)海洋科技與環(huán)境學(xué)院,遼寧 大連 116023；3.上海海洋大學(xué)海洋生態(tài)與環(huán)境學(xué)院,上海 201306；4.海南熱帶海洋學(xué)院生態(tài)環(huán)境學(xué)院,海南 三亞 572022)

利用高效液相色譜-串聯(lián)質(zhì)譜法分析了環(huán)渤海區(qū)域典型河流下游水體中6類58種抗生素的賦存特征,采用生態(tài)風(fēng)險(xiǎn)模型和人類健康風(fēng)險(xiǎn)模型分別評(píng)估了抗生素對(duì)生態(tài)和人體的健康風(fēng)險(xiǎn).結(jié)果顯示:環(huán)渤海區(qū)域4大典型河流(小凌河、灤河、黃河和大遼河)下游水體中有6類50種抗生素被檢出,青霉素G濃度水平最高,最高濃度為353.13ng/L.β-內(nèi)酰胺類、大環(huán)內(nèi)酯類和喹諾酮類為該區(qū)域水體中主要抗生素污染類型.與國(guó)內(nèi)其它河流相比,環(huán)渤海區(qū)域4大河流下游水體中抗生素濃度處于中等污染水平,與國(guó)外河流相比,處于較高的污染水平.抗生素在研究區(qū)域水體中的總濃度水平為124.50～489.16ng/L,平均濃度大小排序?yàn)?小凌河>大遼河>灤河>黃河.風(fēng)險(xiǎn)評(píng)估的結(jié)果表明:阿莫西林、脫水紅霉素和紅霉素對(duì)研究區(qū)域水體中敏感水生物種呈現(xiàn)出高生態(tài)風(fēng)險(xiǎn),四環(huán)素、土霉素、恩若沙星、氧氟沙星和西諾沙星呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn);目標(biāo)抗生素對(duì)不同年齡階段人群的健康風(fēng)險(xiǎn)值在2.53×10-7～6.79×10-3,遠(yuǎn)小于1,抗生素的污染對(duì)環(huán)渤海區(qū)域人群構(gòu)不成健康威脅.

環(huán)渤海區(qū)域；水體；抗生素；風(fēng)險(xiǎn)評(píng)估

抗生素作為高效的抗菌藥物,被廣泛應(yīng)用于人類和動(dòng)物疾病的預(yù)防和治療[1].在被人類和動(dòng)物食用后,大約25%～75%的抗生素會(huì)隨著排泄物以原藥或代謝產(chǎn)物的形式進(jìn)入環(huán)境中[2].盡管排泄的污水通常會(huì)經(jīng)過污水處理廠處理,但在傳統(tǒng)的廢水處理工藝中,抗生素的去除效率僅有36%～79%[3].隨著抗生素的持續(xù)生產(chǎn)和過度使用,環(huán)境中抗生素的污染日趨嚴(yán)重.迄今為止,在地下水[4]、地表水[5]、沉積物[6]、土壤[7]、甚至生物體[8]中都發(fā)現(xiàn)不同種類抗生素的污染.環(huán)境中多種抗生素的污染會(huì)對(duì)生態(tài)系統(tǒng)安全產(chǎn)生負(fù)面影響,一方面其作為有機(jī)化學(xué)物質(zhì),在水生環(huán)境中的殘留會(huì)抑制植物根的生長(zhǎng)[9],水生動(dòng)物和有機(jī)蔬菜對(duì)抗生素的生物累積也可能通過食物鏈或食物網(wǎng)間接對(duì)人類健康造成危害[10];另一方面抗生素會(huì)誘導(dǎo)環(huán)境中產(chǎn)生抗生素抗性細(xì)菌(ARB)和抗生素抗性基因(ARGs)[11].ARGs對(duì)人類和生態(tài)環(huán)境的危害遠(yuǎn)高于抗生素,世衛(wèi)組織認(rèn)為, 在21世紀(jì)抗菌藥物的耐藥性是威脅人類公共健康最大的對(duì)手之一[12].

我國(guó)用于人類治療疾病的處方藥中有70%是抗生素,而發(fā)達(dá)國(guó)家只有30%是抗生素.如今我國(guó)已經(jīng)成為世界上最大的抗生素生產(chǎn)國(guó)和使用國(guó).2013年抗生素的產(chǎn)量估計(jì)是24.8萬(wàn) t,約是2009年總產(chǎn)量的2倍,使用量高達(dá)16.2萬(wàn)t,其中大約有48%被人類使用[13-14].在我國(guó)抗生素的總消耗量中,超過5萬(wàn)t被排放到水體和土壤中[13],抗生素在水環(huán)境中的污染和循環(huán),對(duì)生態(tài)環(huán)境和人類健康構(gòu)成了嚴(yán)重威脅.相比于西方國(guó)家,我國(guó)水環(huán)境中抗生素的濃度和檢出率均處于較高水平[15].目前,針對(duì)我國(guó)不同水系抗生素污染的研究日益增多,在珠江流域[16]、長(zhǎng)江流域[17]、漢江流域[18]、黃河流域[19]、海河流域[20]、遼河流域[21]等均被證實(shí)存在多種抗生素的污染,濃度水平在ng/L～μg/L.鑒于抗生素對(duì)水生環(huán)境的危害性,它們?cè)诓煌貐^(qū)河流中的污染應(yīng)該引起人們重視.

環(huán)渤海區(qū)域由北京市、天津市、河北省、山東省和遼寧省組成,總面積約112萬(wàn)km2,人口約2.6億[22].該地區(qū)是我國(guó)重要的人口密集區(qū)和工業(yè)密集區(qū),其作為我國(guó)經(jīng)濟(jì)增長(zhǎng)的第三極,在現(xiàn)代化經(jīng)濟(jì)體系建設(shè)中具有重要戰(zhàn)略地位[23].隨著城市化進(jìn)程的加快和高度發(fā)達(dá)的工、農(nóng)業(yè)體系建設(shè),不可避免地導(dǎo)致了環(huán)渤海區(qū)域河流水體中新型有機(jī)污染物的污染.據(jù)報(bào)道,環(huán)渤海區(qū)域河網(wǎng)普遍存在多種抗生素的污染,并且證實(shí)河流排放是渤海灣抗生素污染的重要來(lái)源[24].為進(jìn)一步探究環(huán)渤海區(qū)域典型河流下游水體中抗生素污染特征,本研究以該區(qū)域4大入海河流(小凌河、灤河、黃河和大遼河)為研究對(duì)象,探究了各河流水體中58種抗生素的污染特征,并利用風(fēng)險(xiǎn)評(píng)估模型評(píng)估了抗生素污染對(duì)生態(tài)、人類健康造成的風(fēng)險(xiǎn),以期為環(huán)渤海區(qū)域河流抗生素污染防治提供數(shù)據(jù)支撐.

1 材料與方法

1.1 試劑和儀器

主要試劑有:氯霉素類抗生素(APs):甲砜霉素(TAP)、氟苯尼考(FF)、氯霉素(CAP);四環(huán)素類抗生素(TCs):四環(huán)素(TC)、土霉素(OTC)、金霉素(CTC)、強(qiáng)力霉素(DC);磺胺類抗生素(SAs):磺胺醋酰(SCM)、磺胺嘧啶(SDZ)、磺胺噻唑(STZ)、磺胺吡啶(SPD)、磺胺二甲嘧啶(SMT)、磺胺對(duì)甲氧嘧啶(SM)、磺胺間甲氧嘧啶(SMM)、磺胺氯噠嗪(SCP)、磺胺甲基異噁唑(SMX)、磺胺甲噻二唑(SMI)、磺胺甲基嘧啶(SMR)、磺胺二甲氧嗪(SDM)、磺胺甲氧噠嗪(SMP)、磺胺鄰二甲氧嘧啶(SD)、磺胺二甲異噁唑(SIZ);β-內(nèi)酰胺類抗生素(β-Ls):阿莫西林(AMX)、頭孢氨芐(CEL)、頭孢拉定(CRD)、青霉素G(PCG);大環(huán)內(nèi)酯類抗生素(MLs):紅霉素(ETM)、脫水紅霉素(AETM)、螺旋霉素(SPM)、替米考星(TIL)、竹桃霉素(OLE)、泰樂菌素(TYL)、那他霉素(NATA)、吉他霉素(LCM)、維及霉素M1(VGM1);喹諾酮類抗生素(QNs):洛美沙星(LOM)、達(dá)氟沙星(DAN)、恩諾沙星(ENR)、那氟沙星(NF)、氧氟沙星(OFL)、麻保沙星(MAR)、氟羅沙星(FLE)、加替沙星(GAT)、氟甲喹(FLU)、惡喹酸(OXO)、西諾沙星(CIN)、萘啶酸(NDA)、吡呱酸(PIPA)、諾氟沙星(NOR)、依諾沙星(ENO)、沙拉沙星(SAR)、吉米沙星(GMF)、司帕沙星(SPA)、奧比沙星(ORB)、雙氟沙星(DIF)、莫西沙星(MOX)、妥舒沙星(TELX)、環(huán)丙沙星(CIP).回收率指示劑:紅霉素-d3(ETM- d3)、恩諾沙星-d5(ENR-d5)、氯霉素-d5(CAP-d5)、阿莫西林-d4(AMX-d4)、磺胺嘧啶-13C(SDZ-13C).

所有目標(biāo)抗生素中,磺胺類、四環(huán)類、β-內(nèi)酰胺類抗生素購(gòu)自德國(guó)Dr.Ehrenstorfer公司,喹諾酮類、大環(huán)內(nèi)酯類、氯霉素類抗生素購(gòu)自美國(guó)A ChemTek公司;在回收率指示劑中,ETM-d3、CAP-d5、AMX-d4、SDZ-13C購(gòu)自德國(guó)Dr.Ehrenstorfer公司; ENR-d5購(gòu)自上海安譜實(shí)驗(yàn)科技股份有限公司.甲醇、乙腈、甲酸、氨水(均為色譜純)在美國(guó)Tedia公司購(gòu)買;Na2EDTA在天津科密歐公司購(gòu)買;C18反相色譜柱(150mm×2.1mm,3.5μm)和HLB固相萃取柱(Oasis HLB 6cc,200mg)在美國(guó)Waters公司購(gòu)買;醋酸纖維濾膜(0.45μm,50mm)在上海市新亞凈化器件廠購(gòu)買;0.22μm有機(jī)相濾膜在津騰實(shí)驗(yàn)設(shè)備有限公司購(gòu)買.

儀器設(shè)備有:高效液相色譜分析系統(tǒng)(Finnigan Surveyor,Thermo 公司,美國(guó))、質(zhì)譜分析儀(Finnigan TSQ Quantum,Thermo公司,美國(guó))、24位半自動(dòng)固相萃取裝置(VISIPREP 24TM DL,Supelco公司,美國(guó))、氮吹儀(N-EVAP12,北京康林公司,中國(guó))、超純水制造儀(Milli-Q,Millipore公司,美國(guó)).

1.2 區(qū)域概況和樣品采集

本研究于2019年6月對(duì)環(huán)渤海區(qū)域小凌河、灤河、黃河、大遼河下游進(jìn)行樣品采集(118.347°～ 122.267°E,37.595°～41.012°N),一共有18個(gè)采樣點(diǎn),其中小凌河有3個(gè)(XLH1-XLH3),灤河有3個(gè)(LUH4-LUH6),黃河有4個(gè)(HH7-HH10),大遼河有8個(gè)(DLH11-DLH18),共采集20份水樣(包括2份平行樣品).采樣點(diǎn)分布如圖1所示.采集4L河流表層水體裝于棕色玻璃瓶?jī)?nèi),4℃環(huán)境中避光保存.所有水樣于48h內(nèi)完成前處理過程.

圖1 環(huán)渤海區(qū)域典型河流采樣點(diǎn)分布

1.3 實(shí)驗(yàn)方法與質(zhì)量控制

本研究采用固相萃取(SPE)和高效液相色譜串聯(lián)質(zhì)譜(HPLC-MS/MS)分別進(jìn)行了樣品前處理和樣品上機(jī)檢測(cè).前處理過程具體如下:

取1L河水水樣通過0.45 μm醋酸纖維濾膜過濾后,加入0.5g乙二胺四乙酸二鈉(Na2EDTA),用3mol/L的稀硫酸調(diào)節(jié)pH=3.0,加入100ng抗生素回收率指示劑,振蕩混合均勻.將樣品通過HLB(6cc, 200mg)固相萃取柱富集,在富集之前,分別使用10mL甲醇、6mL純水和6mL的0.1%甲酸水溶液對(duì)HLB固相萃取柱進(jìn)行淋洗活化,隨后以3～5mL/ min的流速富集樣品,富集完成后,分別使用5mL的超純水和5mL的10%甲醇水清洗HLB小柱,抽真空干燥30min.將真空干燥的HLB小柱分別用5mL的甲醇和5mL 2%的氨-甲醇洗脫,隨后將裝有洗脫液的玻璃試管轉(zhuǎn)移至40℃水浴鍋中,使用氮吹儀將樣品氮吹至近干(0.2～0.3mL),用0.1%甲酸-甲醇溶液定容至1mL,使用0.22μm有機(jī)相濾膜將定容后的樣品過濾到進(jìn)樣小瓶中,放在-20℃保存,待測(cè).

使用HPLC-MS/MS儀器對(duì)6類抗生素進(jìn)行檢測(cè).SAs、TCs、QNs和APs使用相同的流動(dòng)相,A相為0.1%甲酸水溶液,B相為甲醇,梯度洗脫程序?yàn)?流動(dòng)相B的初始體積為20%,8min時(shí)增長(zhǎng)到80%,穩(wěn)定至10min時(shí)開始下降,在12min時(shí)下降至20%,保持至25min.β-Ls和MLs的流動(dòng)相A相和C相分別為:0.1%甲酸水溶液、乙腈;梯度洗脫程序?yàn)?流動(dòng)相C的初始體積為5%,8min時(shí)增長(zhǎng)到95%,穩(wěn)定至10min時(shí)開始下降,在12min時(shí)下降至5%,保持至25min.

本研究采用外標(biāo)法對(duì)樣品進(jìn)行定量分析,標(biāo)準(zhǔn)曲線濃度范圍為0～100ng/L,擬合效果較好(R>0.99).將空白樣品(實(shí)驗(yàn)室和采樣現(xiàn)場(chǎng))、現(xiàn)場(chǎng)加標(biāo)樣品和平行樣品進(jìn)行上機(jī)分析,空白樣品中抗生素的濃度不超過檢出限.以(/)=3計(jì)算抗生素檢出限,目標(biāo)抗生素的檢出限在0.002～4.839ng/L.SAs、QNs、APs、MLs、β-Ls使用對(duì)應(yīng)的回收率指示劑求取回收率,其中,SAs的回收率在75.89%～92.56%,QNs的回收率在52.14%～90.12%,APs的回收率在45.00%～ 71.78%,MLs的回收率在57.28%～89.14%,β-Ls的回收率在61.12%～91.87%.TCs采用實(shí)驗(yàn)室空白樣品加入目標(biāo)化合物實(shí)驗(yàn)求取回收率,回收率為69.03%～ 88.67%.

1.4 風(fēng)險(xiǎn)評(píng)估模型

生態(tài)風(fēng)險(xiǎn)評(píng)估:根據(jù)歐盟委員會(huì)評(píng)估環(huán)境風(fēng)險(xiǎn)的標(biāo)準(zhǔn),本研究使用風(fēng)險(xiǎn)熵法(RQs)對(duì)環(huán)渤海典型河流水體中抗生素的污染狀況進(jìn)行了生態(tài)風(fēng)險(xiǎn)評(píng)估.計(jì)算公式如下:

式中:MEC為實(shí)際檢測(cè)濃度,ng/L.PNEC為預(yù)測(cè)無(wú)效應(yīng)濃度,ng/L.LC50為半致死濃度,EC50為最大半效應(yīng)濃度,單位均為ng/L.AF為評(píng)價(jià)因子,歐盟關(guān)于風(fēng)險(xiǎn)評(píng)估的技術(shù)指導(dǎo)文件中(TGD)規(guī)定:使用急性毒性數(shù)據(jù)時(shí),AF取1000.Hernando等[25]認(rèn)為:當(dāng)RQs31時(shí),高風(fēng)險(xiǎn);當(dāng)0.1￡RQs<1時(shí),中等風(fēng)險(xiǎn),當(dāng)0.01￡RQs<0.1時(shí),低風(fēng)險(xiǎn).抗生素的毒性數(shù)據(jù)來(lái)源于美國(guó)環(huán)保署生態(tài)毒理學(xué)知識(shí)庫(kù)(ECOTOX)和相關(guān)文獻(xiàn).

人類健康風(fēng)險(xiǎn)評(píng)估:根據(jù)WHO推薦的人類健康風(fēng)險(xiǎn)評(píng)估方法對(duì)研究區(qū)域進(jìn)行了抗生素的人類健康風(fēng)險(xiǎn)評(píng)估(RQH).計(jì)算公式如下:

式中:RQH為抗生素的健康風(fēng)險(xiǎn)熵;DWEL為飲用水當(dāng)量值,μg/L;MEC為抗生素實(shí)測(cè)濃度,μg/L;DWI為每日飲水量,L/d;AB為腸胃吸收率,AB=1;FOE為暴露頻率,FOE=0.96;ADI為日允許攝入量,μg/(kg·d); BW為人均體重,kg;HQ為最大風(fēng)險(xiǎn),HQ=1[26].其中不同年齡階段人群的BW和DWI數(shù)據(jù)采樣美國(guó)EPA推薦值,具體見表1所示.抗生素的ADI數(shù)據(jù)主要從澳大利亞政府衛(wèi)生署、美國(guó)ECOTOX數(shù)據(jù)庫(kù)和文獻(xiàn)報(bào)告中獲得.美國(guó)EPA認(rèn)為,當(dāng)RQH31時(shí),對(duì)人體健康有高風(fēng)險(xiǎn);當(dāng)0.1￡RQH<1時(shí),為中等風(fēng)險(xiǎn);當(dāng)0.01￡RQH<0.1時(shí),為低等風(fēng)險(xiǎn);當(dāng)RQH<0.01時(shí),為無(wú)風(fēng)險(xiǎn)[26].

表1 不同年齡階段體重和日飲用水量推薦值[27]

2 結(jié)果與討論

2.1 抗生素在各河流水體中的賦存特征

在環(huán)渤海區(qū)域18個(gè)河水采樣點(diǎn)中,除STZ、SM、SMM、SMR、LOM、FLU、NOR和CIP沒有被檢出外,其他50種抗生素在該流域典型河流水體中均存在不同程度的污染,具體如表2所示.6大類50種抗生素的濃度水平為N.D.～353.13ng/L, PCG濃度水平最高,其次為AETM,濃度為176.88ng/L.已檢出抗生素的檢出率為6%～100%,其中FF、ETM、AETM檢出率均為100%,TAP、CAP檢出率均為94%,TYL、LCM檢出率均為78%, AMX、CEL、CRD、SPM、OLE檢出率分別為61%、56%、50%、67%、89%,剩余的38種抗生素的檢出率均低于50%.在6大類抗生素中總濃度水平為51.33～1820.42ng/L,總濃度水平最高的是β-Ls,其次是MLs和QNs,總濃度水平分別為1436.36和1086.93ng/L.各類抗生素的總濃度水平大小排序?yàn)?β-Ls>MLs>QNs>APs>TCs>SAs.為了探究不同類型抗生素在環(huán)渤海典型河流水體中的污染特征,本研究對(duì)各類抗生素總濃度水平進(jìn)行了聚類分析,結(jié)果發(fā)現(xiàn),Mls、β-Ls和QNs的濃度水平相對(duì)較高,可聚為一類,APs、TCs和SAs的濃度水平相對(duì)較低,具有相似性,可聚為另一類(圖2A).綜上所述,β-Ls、Mls和QNs是環(huán)渤海區(qū)域典型河流下游水體中主要抗生素污染類型.高污染意味著高消耗,據(jù)報(bào)道,β-Ls、Mls和QNs是我國(guó)華北地區(qū)和東北地區(qū)使用量最高的3類抗生素[13].

4種β-Ls在環(huán)渤海區(qū)域典型河流下游水體中均被檢出,檢出率為39%～61%,該類抗生素的濃度水平為N.D.～353.13ng/L,PCG的濃度高于其它內(nèi)酰胺類抗生素,最高濃度為353.13ng/L,平均濃度為66.54ng/ L.雖然β-Ls在環(huán)境中容易降解[28],但是由于該類抗生素在我國(guó)的高消耗水平,環(huán)境中經(jīng)常發(fā)現(xiàn)它們的存在.MLs的濃度水平為N.D.～176.88ng/L,濃度水平最高的是AETM.該類抗生素的檢出率為6%～100%,其中AETM和ETM的檢出率均為100%. AETM和ETM在環(huán)渤海區(qū)域河流水體中的普遍存在是合理的.ETM被認(rèn)為是最常見的MLs[29],由于其化學(xué)性質(zhì)不穩(wěn)定,在水環(huán)境中容易脫去水分子形成AETM.據(jù)報(bào)道,AETM在我國(guó)使用較為廣泛,僅2013年該抗生素的使用量高達(dá)3.8×106kg[13].在23種QNs中,有19種被檢出(LOM、FLU、NOR和CIP未被檢出),濃度水平為N.D.～111.38ng/L,檢出率為6%～44%. GMF和MOX濃度水平超過100ng/ L,其他的該類抗生素均低于100ng/L.APs在環(huán)渤海區(qū)域典型河流下游水體中的濃度水平為N.D.～ 64.06ng/L,檢出率為94%～100%,盡管該類抗生素的濃度水平不高,但從檢出率的角度來(lái)看,環(huán)渤海區(qū)域下游水體中普遍受到APs的污染.TCs和SAs不僅濃度水平較低(低于40ng/L),而且檢出率也普遍較低(均低于40%).TCs抗生素的低濃度和低檢出是合理的,因?yàn)樵擃惪股卦谒h(huán)境中極易降解[30]. SAs作為典型的獸用抗生素被廣泛應(yīng)用于水產(chǎn)養(yǎng)殖過程中,但在環(huán)渤海區(qū)域典型河流下游水體中該類抗生素濃度水平普遍較低,為N.D.～8.87ng/L.在SAs中,SMX濃度水平和檢出率最高,分別為8.87ng/L和28%.

表2 水體中抗生素的濃度水平

注: “n.d.”為未檢出,下同.

為了將環(huán)渤海4大典型河流水體中抗生素的污染水平與國(guó)內(nèi)外其他地區(qū)河流水體抗生素的污染進(jìn)行比較,本研究在每類抗生素中篩選出檢出率相對(duì)較高、濃度值相對(duì)大或者報(bào)告較為頻繁的抗生素與國(guó)內(nèi)外其他河流進(jìn)行對(duì)比分析.與國(guó)內(nèi)一些典型河流地表水中抗生素的污染水平相比,環(huán)渤海4大典型河流水體的抗生素的總濃度水平雖然低于海河和珠江,但是高于長(zhǎng)江、淮河和漢江,總體上處于中等污染水平.與國(guó)外典型河流水體中抗生素的濃度水平相比,環(huán)渤海4大典型河流水體的抗生素的總濃度普遍高于國(guó)外典型河流,具體如表3所示.

表3 國(guó)內(nèi)外地表水體中抗生素的濃度水平(ng/L)

注: “-”為數(shù)據(jù)缺失.

環(huán)渤海區(qū)域典型河流下游水體中抗生素的污染存在明顯的空間分布特征.在抗生素的濃度水平分布上,小凌河、灤河、黃河、大遼河的18個(gè)采樣點(diǎn)抗生素的總濃度水平為124.50～489.16ng/L, XLH1、XLH2和DLH17抗生素的濃度水平相對(duì)較高,分別為485.68, 489.16和461.78ng/L.一般來(lái)說(shuō),抗生素在水體中分布差異與其環(huán)境行為和使用量有一定的關(guān)系,對(duì)于人口相對(duì)密集和養(yǎng)殖業(yè)發(fā)達(dá)的下游入海河流,由于廢水的直接排放和污水廠處理效率較低,抗生素的污染水平也會(huì)增高[31].小凌河下游水體中各個(gè)采樣點(diǎn)抗生素的總濃度水平為278.84 ～489.16ng/L,平均濃度水平為417.90ng/L.XLH1、XLH2的抗生素的總濃度相對(duì)較高,其中MLs和β-Ls在這2個(gè)采樣點(diǎn)處的貢獻(xiàn)率超過70%.MLs和β-Ls在小凌河下游的排放使得該河流抗生素平均總濃度水平高于其它3條河流.大遼河抗生素的總濃度水平為124.50～461.78ng/L,平均濃度水平為293.19ng/L,其中DLH17抗生素的總濃度水平最高,β-Ls在該點(diǎn)的貢獻(xiàn)率超過85%.由于大遼河所有采樣點(diǎn)均處于人口較為密集的盤錦市區(qū),與灤河和黃河相比,該河流水體中抗生素處于相對(duì)較高的污染水平.灤河和黃河下游水體中抗生素的總濃度水平分別為142.33 ～323.89ng/L、134.77 ～269.93ng/L,平均總濃度水平分別為241.77和204.82ng/L.灤河下游灌區(qū)人口相對(duì)稀少,距離中心城市較遠(yuǎn),抗生素使用和排放在一定程度上受到限制,因此灤河下游水體中抗生素的污染處于相對(duì)較低的水平.黃河下游水體中抗生素濃度水平最低,這可能與該地區(qū)抗生素的使用狀況以及區(qū)域水環(huán)境條件等有關(guān).水環(huán)境中抗生素的賦存受到降雨、溫度、光解作用、微生物代謝和人類活動(dòng)等因素的影響,它們的改變會(huì)造成抗生素分布的復(fù)雜變化[38].各類抗生素在不同采樣點(diǎn)的分布狀況具體如圖2B所示.4條河流水體中抗生素平均總濃度大小排序?yàn)?小凌河(417.90ng/L)>大遼河(293.19ng/L)>灤河(241.77ng/ L)>黃河(204.82ng/L).

圖2 環(huán)渤海區(qū)域典型河流下游水體中抗生素在不同采樣點(diǎn)的濃度水平

2.2 抗生素的生態(tài)風(fēng)險(xiǎn)評(píng)估

本研究篩選了抗生素對(duì)水環(huán)境中3類典型物種(魚類、無(wú)脊椎動(dòng)物、藻類)的急性毒性數(shù)據(jù),并針對(duì)最敏感物種對(duì)應(yīng)的急性毒性數(shù)據(jù),計(jì)算出PNEC值.由于少數(shù)目標(biāo)抗生素在水體中未檢出或者急性毒性數(shù)據(jù)缺失(STZ、SM、SMM、SMR、LOM、OLE、FLU、LCM、DAN、NF、MAR、GAT、NOR、ORB、CIP),本研究對(duì)剩余的6大類43種抗生素進(jìn)行了風(fēng)險(xiǎn)評(píng)估,具體見圖3.

圖3 環(huán)渤海區(qū)域典型河流下游水體中抗生素的生態(tài)風(fēng)險(xiǎn)評(píng)估

環(huán)渤海區(qū)域典型河流下游水體中抗生素對(duì)敏感水生物種的RQs值為0～13.13.其中,AMX、AETM和ETM呈現(xiàn)出高生態(tài)風(fēng)險(xiǎn);TC、OTC、ENR、OFL和CIN呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn);其它抗生素則呈現(xiàn)出低生態(tài)風(fēng)險(xiǎn)或者無(wú)生態(tài)風(fēng)險(xiǎn).AMX、AETM和ETM對(duì)環(huán)渤海區(qū)域水體中藻類均呈現(xiàn)出高生態(tài)風(fēng)險(xiǎn),它們的最大RQs值分別為13.13, 8.84和1.05.AMX在小凌河、大遼河、灤河和黃河水體中均呈現(xiàn)出高生態(tài)風(fēng)險(xiǎn).除在灤河水體中呈現(xiàn)中等生態(tài)風(fēng)險(xiǎn)外, AETM在其它3條河流水體中呈現(xiàn)出高生態(tài)風(fēng)險(xiǎn).ETM僅在小凌河水體中呈現(xiàn)高生態(tài)風(fēng)險(xiǎn),在大遼河、灤河、黃河水體中呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn).TC、OTC、ENR和OFL對(duì)環(huán)渤海區(qū)域水體中藻類呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn),CIN對(duì)無(wú)脊椎動(dòng)物(水蚤)呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn),它們的RQs在0.1～1.TC在小凌河、灤河和大遼河水體中呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn),在黃河水體中呈現(xiàn)出無(wú)生態(tài)風(fēng)險(xiǎn);OTC在小凌河和灤河水體中呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn);ENR在小凌河和黃河水體中呈現(xiàn)中等生態(tài)風(fēng)險(xiǎn),CIN僅在小凌河水體中呈現(xiàn)中等生態(tài)風(fēng)險(xiǎn).綜上所述,AMX、AETM和ETM在環(huán)渤海區(qū)域典型河流下游水體中呈現(xiàn)出高生態(tài)風(fēng)險(xiǎn),對(duì)該流域敏感水生物種存在潛在的生態(tài)風(fēng)險(xiǎn),應(yīng)該引起重視.

2.3 抗生素的人類健康風(fēng)險(xiǎn)評(píng)估

在58種目標(biāo)抗生素中,共有30種在環(huán)渤海區(qū)域典型河流下游水體中未檢出或者它們的ADI值缺失.因此,本研究?jī)H對(duì)剩下的28種抗生素進(jìn)行人類健康風(fēng)險(xiǎn)評(píng)估,ADI參考值如表4所示.如圖4所示,28種抗生素污染水平對(duì)嬰幼兒到成人等不同年齡階段人群的RQH在2.53′10-7～6.79′10-3,環(huán)渤海區(qū)域典型河流下游水體中抗生素的污染對(duì)不同年齡階段的人群均無(wú)健康風(fēng)險(xiǎn)(RQH<0.01).盡管如此,抗生素對(duì)不同年齡階段的人群健康風(fēng)險(xiǎn)呈現(xiàn)出差異性,整體表現(xiàn)為:隨著年齡的增加,RQH有降低的趨勢(shì),其中抗生素對(duì)0～3月的嬰兒的健康風(fēng)險(xiǎn)最高,對(duì)16歲以上人群的健康風(fēng)險(xiǎn)最低.在研究的28種抗生素中,FF和ETM的RQH最高值分別高達(dá)6.79′10-3和6.53′10-3,相比其它抗生素,這2種抗生素的RQH更接近0.01,成為潛在健康風(fēng)險(xiǎn)因素,應(yīng)該引起重視.綜上所述,抗生素在小凌河、大遼河、灤河和黃河下游水體中的污染對(duì)流域周圍不同年齡階段的人體健康尚構(gòu)不成威脅.

表4 ADI參考數(shù)值

圖4 水體中抗生素的人類健康風(fēng)險(xiǎn)評(píng)估

3 結(jié)論

3.1 在環(huán)渤海區(qū)域典型河流下游水體中共有6大類50種抗生素被檢出,濃度水平為N.D.～353.13ng/L, PCG濃度最高.6大類抗生素的總濃度大小排序?yàn)?β-Ls>MLs>QNs>APs>TCs>SAs,其中β-Ls、MLs和QNs成為該流域水體中主要抗生素污染類型.環(huán)渤海區(qū)域典型河流下游水體中抗生素的濃度在國(guó)內(nèi)典型河流中處于中等污染水平,與國(guó)外河流相比,處于較高的污染水平.

3.2 環(huán)渤海區(qū)域4條典型河流下游水體中抗生素的污染水平呈現(xiàn)出一定的差異性,總體表現(xiàn)為:小凌河>大遼河>灤河>黃河.

3.3 生態(tài)健康風(fēng)險(xiǎn)評(píng)估的結(jié)果表明:AMX、AETM和ETM對(duì)研究區(qū)域下游水體中敏感水生物種呈現(xiàn)出高生態(tài)風(fēng)險(xiǎn),TC、OTC、ENR、OFL和CIN對(duì)研究區(qū)域水體中敏感水生物種呈現(xiàn)出中等生態(tài)風(fēng)險(xiǎn).

3.4 人類健康風(fēng)險(xiǎn)評(píng)估的結(jié)果表明:目標(biāo)抗生素對(duì)不同年齡階段人群的RQH在2.53′10-7～6.79′10-3,抗生素的污染對(duì)該流域人群構(gòu)不成健康威脅.

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Occurrences and risk assessment of antibiotics in water bodies of major rivers in Bohai Rim Basin.

ZHAO Fu-qiang1,2, GAO Hui1, LI Rui-jing1, JIN Shuai-chen1, ZHANG Hai-bo1, LI Shi-sheng1,3, ZHANG Ke-yu1,3, SHU Qin1,3, NA Guang-shui1,2,3,4*

(1.National Marine Environmental Monitoring Center, Dalian 116023, China；2.College of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China；3.College of Marine Ecology and Environment, Shanghai Ocean University, Shanghai 201306, China；4.College of Ecology and Environment, Hainan Tropical Ocean University, Sanya 572022, China)., 2022,42(1)：109～118

This study was conducted to characterize the occurrences and accumulation of antibiotics in surface water of each river’s downstream in Bohai Rim Basin and to evaluate their ecological risk and human health risk. The results indicate that 50 antibiotics falling into 6 categories were detected in the lower reaches of four major rivers (Xiaoling, Luanhe, Yellow River and Daliao) in Bohai Rim Basin. Off all kinds of antibiotics, β-Ls, MLs and QNs were dominant in those waterbodies of the basin, of which the concentration of Penicillin G was the highest, up to 353.13ng/L. Compared with other rivers in China, The concentration of antibiotics ranged from 124.50ng/L to 489.16ng/L whose average concentration over the study area was rated at a moderate pollution level, but higher than that in other rivers of China. The accumulation level of different rivers was rated in the order as: Xiaoling River>Daliao River>Luanhe River>Yellow River. In addition, amoxicillin, anhydroerythromycin and erythromycin presented higher ecological risk to sensitive aquatic species than did tetracycline, oxytetracycline, enrofloxacin, ofloxacin and cinoxacin which were evaluated at a moderate ecological risk. According to the threshold of the human health risk value of target antibiotics (2.53×10-7～6.79×10-3), the pollution level of the antibiotics in the Bohai Rim Basin did not become a health threat to people yet.

the Bohai Rim Basin；water；antibiotics；risk assessment

X522,X826

A

1000-6923(2022)01-0109-10

趙富強(qiáng)(1994-),男,河南信陽(yáng)人,大連海洋大學(xué)(國(guó)家海洋環(huán)境監(jiān)測(cè)中心聯(lián)合培養(yǎng))碩士研究生,主要從事多環(huán)境介質(zhì)中新型有機(jī)污染物環(huán)境行為研究.

2021-06-08

國(guó)家重點(diǎn)研發(fā)計(jì)劃(2019YFD0901104);國(guó)家自然科學(xué)基金資助項(xiàng)目(41976222,42006195);自然資源部海洋大氣化學(xué)與全球變化重點(diǎn)實(shí)驗(yàn)室開放基金(GCMAC2010);環(huán)境化學(xué)與生態(tài)毒理學(xué)國(guó)家重點(diǎn)實(shí)驗(yàn)室開放基金(KF2018-05)

* 責(zé)任作者, 研究員, gsna@nmemc.org.cn