污染場地地下水環境污染風險分級評價方法研究

徐瑞(rui)穎1，牛浩博2*，羅(luo)朝暉1，陳 堅2，劉偉江3

(1.中國地質大學(武漢)環(huan)(huan)境學院(yuan)；2.生(sheng)(sheng)態環(huan)(huan)境部(bu)(bu)環(huan)(huan)境規(gui)劃院(yuan)3.生(sheng)(sheng)態環(huan)(huan)境部(bu)(bu)土壤(rang)與農(nong)業(ye)農(nong)村生(sheng)(sheng)態環(huan)(huan)境監管(guan)技術中心(xin)，)

《安全與環境工程》 2022年第1期

摘 要：目前我國(guo)的(de)(de)污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)地(di)(di)(di)地(di)(di)(di)下(xia)(xia)水(shui)(shui)(shui)(shui)環(huan)(huan)(huan)境污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)分(fen)(fen)(fen)(fen)級(ji)評(ping)(ping)(ping)(ping)價(jia)方(fang)(fang)法(fa)(fa)(fa)不(bu)能(neng)完全適合(he)環(huan)(huan)(huan)境管理(li)的(de)(de)要求。從(cong)污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)源負荷、污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)物釋放可(ke)能(neng)性(xing)、受體(ti)特(te)征三個(ge)方(fang)(fang)面，運用層次分(fen)(fen)(fen)(fen)析(xi)法(fa)(fa)(fa)和(he)靈敏(min)度分(fen)(fen)(fen)(fen)析(xi)法(fa)(fa)(fa)對污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)地(di)(di)(di)地(di)(di)(di)下(xia)(xia)水(shui)(shui)(shui)(shui)環(huan)(huan)(huan)境污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)分(fen)(fen)(fen)(fen)級(ji)評(ping)(ping)(ping)(ping)價(jia)指標進(jin)行篩選(xuan)和(he)權重計算，構(gou)(gou)建了污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)地(di)(di)(di)地(di)(di)(di)下(xia)(xia)水(shui)(shui)(shui)(shui)環(huan)(huan)(huan)境污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)分(fen)(fen)(fen)(fen)級(ji)評(ping)(ping)(ping)(ping)價(jia)方(fang)(fang)法(fa)(fa)(fa)，將(jiang)污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)地(di)(di)(di)地(di)(di)(di)下(xia)(xia)水(shui)(shui)(shui)(shui)環(huan)(huan)(huan)境污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)劃分(fen)(fen)(fen)(fen)為(wei)高、中、低三級(ji)，并(bing)運用所(suo)構(gou)(gou)建的(de)(de)評(ping)(ping)(ping)(ping)價(jia)方(fang)(fang)法(fa)(fa)(fa)對兩(liang)個(ge)典(dian)型污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)地(di)(di)(di)地(di)(di)(di)下(xia)(xia)水(shui)(shui)(shui)(shui)環(huan)(huan)(huan)境污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)進(jin)行分(fen)(fen)(fen)(fen)級(ji)評(ping)(ping)(ping)(ping)價(jia)與(yu)驗(yan)證。結果表明(ming)：采用該評(ping)(ping)(ping)(ping)價(jia)方(fang)(fang)法(fa)(fa)(fa)得到的(de)(de)污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)地(di)(di)(di)地(di)(di)(di)下(xia)(xia)水(shui)(shui)(shui)(shui)環(huan)(huan)(huan)境污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)評(ping)(ping)(ping)(ping)價(jia)結果與(yu)現有評(ping)(ping)(ping)(ping)價(jia)方(fang)(fang)法(fa)(fa)(fa)的(de)(de)評(ping)(ping)(ping)(ping)價(jia)結果基本一致(zhi)，并(bing)且可(ke)極大地(di)(di)(di)減少評(ping)(ping)(ping)(ping)價(jia)指標篩選(xuan)及(ji)權重確(que)定的(de)(de)主觀性(xing)，適合(he)于(yu)不(bu)同特(te)征污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)物場(chang)(chang)地(di)(di)(di)地(di)(di)(di)下(xia)(xia)水(shui)(shui)(shui)(shui)環(huan)(huan)(huan)境污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)的(de)(de)風(feng)(feng)險(xian)(xian)評(ping)(ping)(ping)(ping)價(jia)，驗(yan)證了所(suo)構(gou)(gou)建的(de)(de)評(ping)(ping)(ping)(ping)價(jia)方(fang)(fang)法(fa)(fa)(fa)具有合(he)理(li)性(xing)和(he)可(ke)靠性(xing)。該評(ping)(ping)(ping)(ping)價(jia)結果可(ke)為(wei)國(guo)家層面的(de)(de)污(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)地(di)(di)(di)分(fen)(fen)(fen)(fen)級(ji)管理(li)提供(gong)科學依據。

關鍵詞：污(wu)染場地；地下水環境污(wu)染；風險分級；層次分析法；靈敏度分析法

20世紀(ji)80年(nian)代以來(lai)，歐美(mei)發(fa)達國(guo)(guo)(guo)家(jia)逐步將污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)問題納(na)入(ru)國(guo)(guo)(guo)家(jia)環(huan)(huan)境(jing)(jing)(jing)管(guan)(guan)理(li)體(ti)系(xi)中(zhong)，并形成(cheng)了(le)(le)(le)完整、成(cheng)熟的(de)(de)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)分(fen)(fen)級(ji)(ji)(ji)管(guan)(guan)理(li)體(ti)系(xi)。目前，我國(guo)(guo)(guo)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)管(guan)(guan)理(li)相關的(de)(de)法(fa)(fa)律法(fa)(fa)規(gui)、相應的(de)(de)評價方(fang)法(fa)(fa)和管(guan)(guan)理(li)體(ti)系(xi)已經逐漸(jian)建立起來(lai)，但在污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)分(fen)(fen)級(ji)(ji)(ji)分(fen)(fen)類(lei)管(guan)(guan)理(li)方(fang)面還(huan)處于(yu)起步階(jie)段[1-2]。2017年(nian)，為了(le)(le)(le)支(zhi)撐全國(guo)(guo)(guo)土壤環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)狀(zhuang)況(kuang)詳查(cha)(cha)工(gong)作(zuo)，建立了(le)(le)(le)優先管(guan)(guan)控名錄(lu)，對重點行(xing)業(ye)出臺了(le)(le)(le)《關閉(bi)搬遷企業(ye)地(di)(di)(di)塊風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)篩查(cha)(cha)與風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)分(fen)(fen)級(ji)(ji)(ji)技術規(gui)定(試行(xing))》。該(gai)(gai)規(gui)定中(zhong)對污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)等(deng)級(ji)(ji)(ji)評估主要基于(yu)初步采樣調查(cha)(cha)結果，采用“源—途(tu)徑—受體(ti)”風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)三要素的(de)(de)評價方(fang)法(fa)(fa)。與發(fa)達國(guo)(guo)(guo)家(jia)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)分(fen)(fen)級(ji)(ji)(ji)管(guan)(guan)理(li)體(ti)系(xi)相比，該(gai)(gai)評價方(fang)法(fa)(fa)考(kao)(kao)慮(lv)的(de)(de)因素較(jiao)少，評價指(zhi)標(biao)賦分(fen)(fen)方(fang)法(fa)(fa)主觀性較(jiao)強。另外，污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)分(fen)(fen)級(ji)(ji)(ji)分(fen)(fen)類(lei)系(xi)統僅僅是一個(ge)篩查(cha)(cha)工(gong)具，是否需(xu)要采取修復行(xing)動還(huan)依賴于(yu)大量因素[3]。美(mei)國(guo)(guo)(guo)環(huan)(huan)境(jing)(jing)(jing)保護署(EPA)于(yu)1995年(nian)8月設立了(le)(le)(le)一個(ge)由(you)(you)項目專家(jia)組成(cheng)的(de)(de)國(guo)(guo)(guo)家(jia)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)優先小組，對污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)分(fen)(fen)級(ji)(ji)(ji)評估的(de)(de)方(fang)法(fa)(fa)除(chu)了(le)(le)(le)考(kao)(kao)慮(lv)對人體(ti)健康和環(huan)(huan)境(jing)(jing)(jing)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)有(you)關的(de)(de)指(zhi)標(biao)外，還(huan)考(kao)(kao)慮(lv)了(le)(le)(le)創新(xin)技術、成(cheng)本(ben)延遲、環(huan)(huan)境(jing)(jing)(jing)正義等(deng)指(zhi)標(biao)，該(gai)(gai)機(ji)構利用這些指(zhi)標(biao)評估為超級(ji)(ji)(ji)基金(jin)項目中(zhong)所有(you)新(xin)的(de)(de)清潔建設項目確定資金(jin)的(de)(de)優先使用次序[4]。由(you)(you)此(ci)可(ke)見，對于(yu)確定污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)修復的(de)(de)優先順序需(xu)要考(kao)(kao)慮(lv)的(de)(de)因素是多途(tu)徑、多方(fang)面的(de)(de)，我國(guo)(guo)(guo)目前的(de)(de)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)環(huan)(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)(feng)險(xian)(xian)(xian)(xian)分(fen)(fen)級(ji)(ji)(ji)評價方(fang)法(fa)(fa)仍需(xu)進一步改進。

污染(ran)場(chang)地(di)(di)地(di)(di)下水(shui)環境(jing)污染(ran)風(feng)險(xian)(xian)分(fen)級評(ping)(ping)價的方法主要有迭置指數(shu)法、過程模擬(ni)法和統計分(fen)析法。其中，迭置指數(shu)法是通過構(gou)建表征污染(ran)場(chang)地(di)(di)地(di)(di)下水(shui)環境(jing)污染(ran)風(feng)險(xian)(xian)的評(ping)(ping)價指標體系(xi)(xi)，按照特定(ding)的評(ping)(ping)分(fen)原則得到分(fen)級對象的風(feng)險(xian)(xian)指數(shu)，并根據風(feng)險(xian)(xian)指數(shu)評(ping)(ping)價污染(ran)場(chang)地(di)(di)地(di)(di)下水(shui)環境(jing)污染(ran)風(feng)險(xian)(xian)的大小[5-7]，如美國污染(ran)場(chang)地(di)(di)危害等級打分(fen)系(xi)(xi)統(HRS)、加拿大污染(ran)場(chang)地(di)(di)國家分(fen)級系(xi)(xi)統

(NCSCS)等(deng)，該方法(fa)(fa)考(kao)慮指標(biao)全(quan)面(mian)(mian)、計(ji)算簡單方便，但(dan)在(zai)確(que)(que)定(ding)評(ping)(ping)(ping)價(jia)指標(biao)權(quan)重(zhong)時(shi)(shi)存(cun)在(zai)較強(qiang)的(de)(de)(de)(de)(de)主(zhu)(zhu)觀(guan)性(xing)(xing)(xing)，且對(dui)污(wu)(wu)(wu)染(ran)形成(cheng)的(de)(de)(de)(de)(de)機理描述得不夠全(quan)面(mian)(mian)[8-9]；過程(cheng)模(mo)(mo)擬(ni)法(fa)(fa)通常是基(ji)于(yu)水(shui)流(liu)和(he)溶(rong)質運移(yi)模(mo)(mo)型，模(mo)(mo)擬(ni)污(wu)(wu)(wu)染(ran)物在(zai)介(jie)(jie)質中(zhong)遷(qian)(qian)移(yi)轉化(hua)的(de)(de)(de)(de)(de)時(shi)(shi)空(kong)變化(hua)規律[10-11]，如(ru)RBCA、3MRA、HERA等(deng)模(mo)(mo)型，該方法(fa)(fa)對(dui)污(wu)(wu)(wu)染(ran)物在(zai)環(huan)(huan)境介(jie)(jie)質中(zhong)的(de)(de)(de)(de)(de)遷(qian)(qian)移(yi)轉化(hua)過程(cheng)進行了(le)定(ding)量(liang)化(hua)描述，主(zhu)(zhu)觀(guan)性(xing)(xing)(xing)低，但(dan)過程(cheng)模(mo)(mo)擬(ni)法(fa)(fa)需要(yao)(yao)收集大(da)量(liang)的(de)(de)(de)(de)(de)參數(shu)，操(cao)作性(xing)(xing)(xing)較差，對(dui)于(yu)全(quan)國(guo)性(xing)(xing)(xing)的(de)(de)(de)(de)(de)污(wu)(wu)(wu)染(ran)場(chang)地(di)(di)地(di)(di)下(xia)水(shui)環(huan)(huan)境污(wu)(wu)(wu)染(ran)風險分(fen)(fen)級(ji)分(fen)(fen)類管理而言不易推(tui)廣[12]；統(tong)計(ji)分(fen)(fen)析(xi)(xi)法(fa)(fa)是基(ji)于(yu)污(wu)(wu)(wu)染(ran)場(chang)地(di)(di)地(di)(di)下(xia)水(shui)監測數(shu)據及資料(liao)，運用(yong)統(tong)計(ji)學方法(fa)(fa)(如(ru)聚類分(fen)(fen)析(xi)(xi)、主(zhu)(zhu)成(cheng)分(fen)(fen)分(fen)(fen)析(xi)(xi)等(deng)方法(fa)(fa))篩(shai)選出地(di)(di)下(xia)水(shui)環(huan)(huan)境污(wu)(wu)(wu)染(ran)的(de)(de)(de)(de)(de)主(zhu)(zhu)要(yao)(yao)影響因素，并通過回歸方程(cheng)給出其(qi)適當(dang)的(de)(de)(de)(de)(de)權(quan)重(zhong)值，該方法(fa)(fa)避(bi)免了(le)專家評(ping)(ping)(ping)判的(de)(de)(de)(de)(de)主(zhu)(zhu)觀(guan)性(xing)(xing)(xing)，但(dan)需要(yao)(yao)大(da)量(liang)的(de)(de)(de)(de)(de)實際數(shu)據，其(qi)應(ying)用(yong)受到限(xian)制(zhi)[13-14]。目前污(wu)(wu)(wu)染(ran)場(chang)地(di)(di)地(di)(di)下(xia)水(shui)環(huan)(huan)境污(wu)(wu)(wu)染(ran)風險的(de)(de)(de)(de)(de)分(fen)(fen)級(ji)評(ping)(ping)(ping)價(jia)方法(fa)(fa)多采用(yong)迭置(zhi)指數(shu)法(fa)(fa)，但(dan)該方法(fa)(fa)主(zhu)(zhu)觀(guan)性(xing)(xing)(xing)較強(qiang)[8-9,15]。為了(le)保(bao)證(zheng)污(wu)(wu)(wu)染(ran)場(chang)地(di)(di)地(di)(di)下(xia)水(shui)環(huan)(huan)境污(wu)(wu)(wu)染(ran)風險分(fen)(fen)級(ji)評(ping)(ping)(ping)價(jia)過程(cheng)的(de)(de)(de)(de)(de)易操(cao)作性(xing)(xing)(xing)，降低評(ping)(ping)(ping)價(jia)指標(biao)篩(shai)選及權(quan)重(zhong)確(que)(que)定(ding)過程(cheng)中(zhong)的(de)(de)(de)(de)(de)主(zhu)(zhu)觀(guan)性(xing)(xing)(xing)，使評(ping)(ping)(ping)價(jia)結果(guo)更加客觀(guan)合理，本文基(ji)于(yu)迭置(zhi)指數(shu)法(fa)(fa)并結合層次分(fen)(fen)析(xi)(xi)法(fa)(fa)和(he)靈(ling)敏度分(fen)(fen)析(xi)(xi)法(fa)(fa)，構建(jian)了(le)污(wu)(wu)(wu)染(ran)場(chang)地(di)(di)地(di)(di)下(xia)水(shui)環(huan)(huan)境污(wu)(wu)(wu)染(ran)風險分(fen)(fen)級(ji)評(ping)(ping)(ping)價(jia)方法(fa)(fa)，以期(qi)為后續制(zhi)定(ding)綜合、全(quan)面(mian)(mian)的(de)(de)(de)(de)(de)污(wu)(wu)(wu)染(ran)場(chang)地(di)(di)地(di)(di)下(xia)水(shui)環(huan)(huan)境污(wu)(wu)(wu)染(ran)風險分(fen)(fen)級(ji)管理方法(fa)(fa)提供借鑒。

1 研究方法

1.1 評價指標選取方法

土(tu)(tu)壤中(zhong)(zhong)(zhong)(zhong)的污(wu)(wu)染(ran)物(wu)經淋(lin)濾作用進(jin)(jin)入包(bao)(bao)氣帶(dai)和含(han)水層，可(ke)在包(bao)(bao)氣帶(dai)介質(zhi)和含(han)水層介質(zhi)中(zhong)(zhong)(zhong)(zhong)發生各種稀(xi)釋衰(shuai)減作用[11-17]。稀(xi)釋衰(shuai)減模(mo)(mo)(mo)型(xing)(xing)(xing)可(ke)對(dui)污(wu)(wu)染(ran)物(wu)在包(bao)(bao)氣帶(dai)和含(han)水層中(zhong)(zhong)(zhong)(zhong)釋放的可(ke)能(neng)性進(jin)(jin)行定(ding)量化描述(shu)，如早期(qi)用于(yu)評估農業區農藥污(wu)(wu)染(ran)地(di)(di)下水脆(cui)弱性的衰(shuai)減因子(zi)(zi)指數(shu)模(mo)(mo)(mo)型(xing)(xing)(xing)——AF、PRZM模(mo)(mo)(mo)型(xing)(xing)(xing)，模(mo)(mo)(mo)型(xing)(xing)(xing)結果(guo)(guo)的取(qu)(qu)(qu)值(zhi)范圍為0～1。當(dang)模(mo)(mo)(mo)型(xing)(xing)(xing)結果(guo)(guo)取(qu)(qu)(qu)值(zhi)為1時，表(biao)明(ming)土(tu)(tu)壤中(zhong)(zhong)(zhong)(zhong)所有(you)污(wu)(wu)染(ran)物(wu)都(dou)有(you)可(ke)能(neng)滲入地(di)(di)下水；而(er)當(dang)模(mo)(mo)(mo)型(xing)(xing)(xing)結果(guo)(guo)取(qu)(qu)(qu)值(zhi)為0時，表(biao)明(ming)土(tu)(tu)壤中(zhong)(zhong)(zhong)(zhong)所有(you)污(wu)(wu)染(ran)物(wu)不會滲入地(di)(di)下水[18-19]。姚文鋒[20]采用包(bao)(bao)氣帶(dai)的氮(dan)淋(lin)溶(rong)系數(shu)即衰(shuai)減因子(zi)(zi)對(dui)研(yan)究(jiu)區地(di)(di)下水水質(zhi)脆(cui)弱性進(jin)(jin)行了評價，結果(guo)(guo)表(biao)明(ming)：包(bao)(bao)氣帶(dai)氮(dan)淋(lin)溶(rong)系數(shu)越小，則地(di)(di)下水水質(zhi)脆(cui)弱性越低(di)；相反，如果(guo)(guo)包(bao)(bao)氣帶(dai)氮(dan)淋(lin)溶(rong)系數(shu)越大，表(biao)明(ming)包(bao)(bao)氣帶(dai)中(zhong)(zhong)(zhong)(zhong)氮(dan)素的損失量越少，則地(di)(di)下水水質(zhi)脆(cui)弱性越高。本文選取(qu)(qu)(qu)模(mo)(mo)(mo)擬污(wu)(wu)染(ran)物(wu)在土(tu)(tu)壤中(zhong)(zhong)(zhong)(zhong)遷移運(yun)輸(shu)過(guo)程的稀(xi)釋衰(shuai)減模(mo)(mo)(mo)型(xing)(xing)(xing)，對(dui)土(tu)(tu)壤中(zhong)(zhong)(zhong)(zhong)污(wu)(wu)染(ran)物(wu)釋放的可(ke)能(neng)性進(jin)(jin)行評價。稀(xi)釋衰(shuai)減模(mo)(mo)(mo)型(xing)(xing)(xing)的計(ji)算公式如下：

(1)

式(shi)(shi)中：LF為(wei)(wei)(wei)土壤稀釋衰減(jian)因(yin)(yin)子(zi)(g/cm3)；SAM為(wei)(wei)(wei)土壤衰減(jian)因(yin)(yin)子(zi)(無(wu)(wu)量(liang)綱)，計(ji)算(suan)(suan)式(shi)(shi)見公(gong)(gong)(gong)(gong)(gong)式(shi)(shi)(2)；LDF為(wei)(wei)(wei)土壤淋濾因(yin)(yin)子(zi)(無(wu)(wu)量(liang)綱)，計(ji)算(suan)(suan)式(shi)(shi)見公(gong)(gong)(gong)(gong)(gong)式(shi)(shi)(3)；Ksw為(wei)(wei)(wei)總土壤-水分配系(xi)數(cm3/g)，計(ji)算(suan)(suan)式(shi)(shi)見公(gong)(gong)(gong)(gong)(gong)式(shi)(shi)(4)；BDF為(wei)(wei)(wei)生物衰減(jian)因(yin)(yin)子(zi)(無(wu)(wu)量(liang)綱)，計(ji)算(suan)(suan)式(shi)(shi)見公(gong)(gong)(gong)(gong)(gong)式(shi)(shi)(5)；TAF為(wei)(wei)(wei)時間平(ping)均因(yin)(yin)子(zi)(無(wu)(wu)量(liang)綱)，計(ji)算(suan)(suan)式(shi)(shi)見公(gong)(gong)(gong)(gong)(gong)式(shi)(shi)(6)。具體計(ji)算(suan)(suan)公(gong)(gong)(gong)(gong)(gong)式(shi)(shi)如下：

(2)

(3)

(4)

(5)

(6)

式(shi)(shi)中(zhong)：L1為(wei)污染(ran)土層厚度(m)；L2為(wei)土壤(rang)(rang)(rang)包(bao)(bao)氣(qi)(qi)帶(dai)厚度(m)；I為(wei)土壤(rang)(rang)(rang)水(shui)(shui)入滲(shen)速(su)率(m/a)；v為(wei)地(di)下(xia)(xia)水(shui)(shui)流(liu)速(su)(m/d)，計(ji)(ji)算式(shi)(shi)見公(gong)式(shi)(shi)(7)；δ為(wei)地(di)下(xia)(xia)水(shui)(shui)混合區厚度(m)；W為(wei)污染(ran)源寬度(m)；θws為(wei)土壤(rang)(rang)(rang)包(bao)(bao)氣(qi)(qi)帶(dai)孔隙水(shui)(shui)體(ti)積比(無量綱(gang))；Kd為(wei)土壤(rang)(rang)(rang)-水(shui)(shui)分配系(xi)數(shu)(shu)(shu)(cm3/g)，計(ji)(ji)算式(shi)(shi)見公(gong)式(shi)(shi)(8)；ρb為(wei)土壤(rang)(rang)(rang)干容重(g/cm3)；H′為(wei)環境(jing)溫度下(xia)(xia)的亨利常(chang)數(shu)(shu)(shu)；θas為(wei)土壤(rang)(rang)(rang)包(bao)(bao)氣(qi)(qi)帶(dai)孔隙空氣(qi)(qi)體(ti)積比(無量綱(gang))；λ為(wei)一階衰減常(chang)數(shu)(shu)(shu)(d-1)；Bw為(wei)自由水(shui)(shui)分配系(xi)數(shu)(shu)(shu)(無量綱(gang))，計(ji)(ji)算式(shi)(shi)見公(gong)式(shi)(shi)(9)；ED為(wei)暴露周期(a)。具體(ti)計(ji)(ji)算公(gong)式(shi)(shi)如下(xia)(xia)：

v=K×i

(7)

Kd=Koc×foc

(8)

Bw=θws+Kdρb+Hθas

(9)

上(shang)式中：K為含(han)水(shui)層水(shui)力(li)傳(chuan)導(dao)系數(shu)(m/d)；i為水(shui)力(li)梯度(無量綱)；Koc為有機碳(tan)-水(shui)分配系數(shu)(cm3/g)；foc為土(tu)壤(rang)有機碳(tan)含(han)量(g/g)；H為亨(heng)利常數(shu)(無量綱)。

模型(xing)(xing)(xing)參(can)數(shu)靈(ling)敏度分析(xi)(xi)是描述模型(xing)(xing)(xing)輸入的(de)(de)(de)(de)變(bian)化對模型(xing)(xing)(xing)輸出響(xiang)應的(de)(de)(de)(de)影響(xiang)程(cheng)(cheng)度，在決(jue)策分析(xi)(xi)、風(feng)險評(ping)(ping)估、模型(xing)(xing)(xing)簡化及優化等(deng)多個方面得(de)到了廣泛應用[21-24]。由于稀(xi)釋衰(shuai)減模型(xing)(xing)(xing)所含的(de)(de)(de)(de)參(can)數(shu)較(jiao)多且計算過(guo)程(cheng)(cheng)繁瑣，故(gu)本文采用靈(ling)敏度分析(xi)(xi)方法對稀(xi)釋衰(shuai)減模型(xing)(xing)(xing)參(can)數(shu)進行(xing)分析(xi)(xi)，識別出主要的(de)(de)(de)(de)影響(xiang)參(can)數(shu)并將其作為污(wu)染(ran)(ran)(ran)物(wu)釋放(fang)可能(neng)性評(ping)(ping)價指標(biao)，以此(ci)降低指標(biao)篩選的(de)(de)(de)(de)主觀(guan)性。但由于稀(xi)釋衰(shuai)減模型(xing)(xing)(xing)模擬(ni)污(wu)染(ran)(ran)(ran)物(wu)在環境介質中(zhong)的(de)(de)(de)(de)遷移轉化過(guo)程(cheng)(cheng)時對污(wu)染(ran)(ran)(ran)源負(fu)荷(he)和(he)受(shou)體特征等(deng)相(xiang)關要素(su)的(de)(de)(de)(de)考(kao)慮不足，故(gu)本文通過(guo)查閱相(xiang)關文獻資料并結合已有的(de)(de)(de)(de)研究成果(guo)還選取(qu)了污(wu)染(ran)(ran)(ran)源負(fu)荷(he)和(he)受(shou)體特征評(ping)(ping)價指標(biao)，最終(zhong)將污(wu)染(ran)(ran)(ran)源負(fu)荷(he)、污(wu)染(ran)(ran)(ran)物(wu)釋放(fang)可能(neng)性和(he)受(shou)體特征三個方面的(de)(de)(de)(de)評(ping)(ping)價指標(biao)加權疊加構建了污(wu)染(ran)(ran)(ran)場地地下水環境污(wu)染(ran)(ran)(ran)風(feng)險分級評(ping)(ping)價方法，具體思路流程(cheng)(cheng)圖見圖1。

圖1 污染(ran)場(chang)地(di)(di)地(di)(di)下水(shui)環境污染(ran)風(feng)險分級評價方法構建(jian)流程圖

Fig.1 Flow chart of groundwater pollution risk classification evaluation method for contaminated sites

1.2 評價指標權重的確定方法

評(ping)(ping)價指(zhi)標(biao)(biao)權(quan)重(zhong)的(de)(de)確(que)定方法(fa)主(zhu)(zhu)要有(you)專家打(da)分法(fa)、層(ceng)次(ci)(ci)分析法(fa)等[25-26]。其中，專家打(da)分法(fa)具(ju)有(you)較(jiao)強的(de)(de)主(zhu)(zhu)觀隨意(yi)性(xing)，客觀性(xing)差；層(ceng)次(ci)(ci)分析法(fa)將相(xiang)關評(ping)(ping)價指(zhi)標(biao)(biao)按支配關系(xi)分成若干層(ceng)次(ci)(ci)，對同一(yi)層(ceng)次(ci)(ci)各評(ping)(ping)價指(zhi)標(biao)(biao)進行(xing)兩兩比較(jiao)，以獲得各評(ping)(ping)價指(zhi)標(biao)(biao)間的(de)(de)相(xiang)對重(zhong)要性(xing)，但(dan)在確(que)定指(zhi)標(biao)(biao)相(xiang)對重(zhong)要性(xing)時仍具(ju)有(you)一(yi)定的(de)(de)主(zhu)(zhu)觀性(xing)[27-28]。因(yin)此，本文將模型參數的(de)(de)靈敏(min)度分析結果與(yu)層(ceng)次(ci)(ci)分析法(fa)相(xiang)結合，對靈敏(min)度較(jiao)高(gao)的(de)(de)參數賦予更(geng)高(gao)的(de)(de)權(quan)重(zhong)，以此來降低評(ping)(ping)價指(zhi)標(biao)(biao)權(quan)重(zhong)確(que)定過(guo)程中的(de)(de)主(zhu)(zhu)觀性(xing)。

1.3 評價指標分級評分方法

各評(ping)(ping)(ping)價指(zhi)標(biao)內(nei)部分(fen)(fen)級(ji)值參(can)考(kao)相(xiang)關文獻，優先參(can)考(kao)已(yi)有評(ping)(ping)(ping)價模型中的評(ping)(ping)(ping)價指(zhi)標(biao)分(fen)(fen)級(ji)，若國內(nei)外參(can)考(kao)文獻中未有說明，可查閱國內(nei)外相(xiang)關污染因子分(fen)(fen)級(ji)標(biao)準，并根(gen)據(ju)各評(ping)(ping)(ping)價指(zhi)標(biao)實際風險大小且結(jie)合專家對評(ping)(ping)(ping)價指(zhi)標(biao)的評(ping)(ping)(ping)分(fen)(fen)情況進行分(fen)(fen)級(ji)評(ping)(ping)(ping)價，評(ping)(ping)(ping)分(fen)(fen)值范圍為1～10[25-26,29]。

1.4 總分計算方法

污染(ran)場地地下水環境(jing)污染(ran)風(feng)險評價(jia)綜合指(zhi)數的總(zong)分計算采(cai)用評價(jia)指(zhi)標加(jia)權求和法，其計算公式如(ru)下：

(10)

式中：m為(wei)(wei)評(ping)價指(zhi)(zhi)(zhi)標(biao)的個(ge)(ge)數(shu)(個(ge)(ge))；xi為(wei)(wei)評(ping)價指(zhi)(zhi)(zhi)標(biao)i的評(ping)分值(分)；wi為(wei)(wei)評(ping)價指(zhi)(zhi)(zhi)標(biao)i的總(zong)權重；R為(wei)(wei)污染場(chang)地(di)(di)地(di)(di)下水(shui)環境(jing)污染風險評(ping)價綜合指(zhi)(zhi)(zhi)數(shu)的總(zong)分值。

評價(jia)結果R取值(zhi)(zhi)范(fan)圍為(wei)(wei)1～10分(fen)，根據(ju)污染場(chang)地(di)得分(fen)值(zhi)(zhi)(R值(zhi)(zhi))將污染場(chang)地(di)地(di)下水環境污染風險(xian)(xian)等(deng)間(jian)距(ju)劃分(fen)為(wei)(wei)以下3個等(deng)級：當R值(zhi)(zhi)為(wei)(wei)1～4分(fen)時(shi)，為(wei)(wei)低污染風險(xian)(xian)場(chang)地(di)；當R值(zhi)(zhi)為(wei)(wei)4～7分(fen)時(shi)，為(wei)(wei)中污染風險(xian)(xian)場(chang)地(di)；當R值(zhi)(zhi)為(wei)(wei)7～10分(fen)時(shi)，為(wei)(wei)高污染風險(xian)(xian)場(chang)地(di)。

2 評價指標篩選與風險分級評價方法的構建

2.1 評價指標篩選

2.1.1 污染(ran)源負荷和受(shou)體(ti)特(te)征評價(jia)指(zhi)標選(xuan)取

污(wu)染(ran)(ran)源負(fu)荷指標(biao)(biao)主要(yao)描(miao)述污(wu)染(ran)(ran)場(chang)地環境(jing)污(wu)染(ran)(ran)的(de)嚴(yan)重(zhong)程度，參(can)(can)考(kao)國內外污(wu)染(ran)(ran)場(chang)地環境(jing)污(wu)染(ran)(ran)風(feng)險(xian)等級(ji)評價系統中的(de)指標(biao)(biao)，選取土(tu)壤(rang)污(wu)染(ran)(ran)物(wu)(wu)超標(biao)(biao)倍數(shu)、土(tu)壤(rang)污(wu)染(ran)(ran)物(wu)(wu)超標(biao)(biao)范圍作為污(wu)染(ran)(ran)源負(fu)荷評價指標(biao)(biao)；受體(ti)(ti)特征指標(biao)(biao)主要(yao)反(fan)映受體(ti)(ti)的(de)易損性，主要(yao)參(can)(can)考(kao)國內《關閉搬遷企業風(feng)險(xian)篩查與風(feng)險(xian)分(fen)級(ji)技術規定(ding)(試行(xing))》中的(de)指標(biao)(biao)，選取地下水(shui)(shui)及鄰近地表水(shui)(shui)利用類型(xing)、場(chang)地及周邊500 m內人口數(shu)量、重(zhong)點(dian)區域離(li)(li)最近敏感點(dian)距離(li)(li)作為受體(ti)(ti)特征指標(biao)(biao)。土(tu)壤(rang)污(wu)染(ran)(ran)物(wu)(wu)超標(biao)(biao)范圍按(an)最大污(wu)染(ran)(ran)土(tu)壤(rang)方量計(ji)；土(tu)壤(rang)污(wu)染(ran)(ran)物(wu)(wu)超標(biao)(biao)總倍數(shu)按(an)下式計(ji)算：

(11)

式中：P為(wei)土(tu)壤(rang)污(wu)染(ran)物(wu)超標總倍(bei)數(倍(bei))；Ci為(wei)土(tu)壤(rang)中第i個(ge)污(wu)染(ran)物(wu)濃(nong)度的實測(ce)值(zhi)，取(qu)所有土(tu)壤(rang)樣品測(ce)試數據中的最(zui)高(gao)值(zhi)(mg/kg);Coi為(wei)土(tu)壤(rang)中第i個(ge)污(wu)染(ran)物(wu)濃(nong)度的標準值(zhi)(mg/kg)，參考《土(tu)壤(rang)環境(jing)質量(liang) 建設(she)用地土(tu)壤(rang)污(wu)染(ran)風險管(guan)控標準(試行)》(GB 36600—2018)中的篩選值(zhi)；n為(wei)土(tu)壤(rang)中污(wu)染(ran)物(wu)個(ge)數(個(ge))。

2.1.2 污染物(wu)釋(shi)放可能性(xing)評價指標選取

局部(bu)靈(ling)(ling)(ling)敏(min)(min)(min)(min)度分(fen)(fen)(fen)析(xi)(xi)方(fang)(fang)法中參(can)(can)數(shu)(shu)(shu)靈(ling)(ling)(ling)敏(min)(min)(min)(min)度會隨參(can)(can)數(shu)(shu)(shu)初始值位置的(de)變(bian)化(hua)有較大(da)的(de)波動，從而導致參(can)(can)數(shu)(shu)(shu)靈(ling)(ling)(ling)敏(min)(min)(min)(min)度排序不穩定[30-31]，因此本研(yan)究選取(qu)(qu)區(qu)域靈(ling)(ling)(ling)敏(min)(min)(min)(min)度分(fen)(fen)(fen)析(xi)(xi)方(fang)(fang)法。根據區(qu)域靈(ling)(ling)(ling)敏(min)(min)(min)(min)度分(fen)(fen)(fen)析(xi)(xi)原理[32-33]，采(cai)(cai)用蒙(meng)特卡洛(luo)抽樣方(fang)(fang)法在各參(can)(can)數(shu)(shu)(shu)區(qu)間內(見(jian)(jian)表(biao)1)隨機采(cai)(cai)樣，計(ji)算每組參(can)(can)數(shu)(shu)(shu)對應的(de)輸出結果，即土(tu)壤稀釋衰減因子，并取(qu)(qu)輸出結果的(de)前5%所對應的(de)參(can)(can)數(shu)(shu)(shu)作(zuo)為可接(jie)受參(can)(can)數(shu)(shu)(shu)，利用K-S檢驗分(fen)(fen)(fen)析(xi)(xi)可接(jie)受參(can)(can)數(shu)(shu)(shu)分(fen)(fen)(fen)布與(yu)原始參(can)(can)數(shu)(shu)(shu)分(fen)(fen)(fen)布的(de)差異，兩者之(zhi)間差異越(yue)大(da)表(biao)明參(can)(can)數(shu)(shu)(shu)的(de)靈(ling)(ling)(ling)敏(min)(min)(min)(min)度越(yue)高(gao)。若參(can)(can)數(shu)(shu)(shu)的(de)顯著(zhu)性水平小于0.05[26]，則認(ren)為參(can)(can)數(shu)(shu)(shu)的(de)靈(ling)(ling)(ling)敏(min)(min)(min)(min)度顯著(zhu)。各參(can)(can)數(shu)(shu)(shu)區(qu)域靈(ling)(ling)(ling)敏(min)(min)(min)(min)度分(fen)(fen)(fen)析(xi)(xi)結果，見(jian)(jian)表(biao)2。

表1 稀釋衰減(jian)模型參數的取(qu)值范圍[34-36]

Table 1 Range of dulition attenuation model parameters[34-36]

表2 稀釋衰(shuai)減模型參數K-S檢驗(yan)的統計量和顯著性水平

Table 2 K-S statisic of dulition attenuation model parameters

通過對比各參數(shu)(shu)的顯著性水平，可得(de)出靈敏度顯著的參數(shu)(shu)有(you)污染(ran)物分配系數(shu)(shu)(lgKoc)、土壤(rang)水入滲速率(lv)(I)、一階(jie)衰減(jian)常數(shu)(shu)(λ)、未(wei)污染(ran)土壤(rang)厚(hou)度(D)、土壤(rang)有(you)機(ji)碳含量(foc)。

2.2 評價指標權重的確定

首(shou)先(xian)，通過層(ceng)(ceng)次(ci)分析法(fa)建立污(wu)染(ran)場(chang)地地下水環境污(wu)染(ran)風險評價的(de)(de)遞階層(ceng)(ceng)次(ci)結構，共分為三個(ge)層(ceng)(ceng)次(ci)，即目標(biao)(biao)層(ceng)(ceng)、準則層(ceng)(ceng)和指(zhi)標(biao)(biao)層(ceng)(ceng)；然后，結合污(wu)染(ran)物釋放可能性評價指(zhi)標(biao)(biao)的(de)(de)靈敏度分析結果，采用1～9標(biao)(biao)度法(fa)構造判斷(duan)矩陣(zhen)，以判斷(duan)矩陣(zhen)為基礎(chu)計算判斷(duan)矩陣(zhen)的(de)(de)特(te)征(zheng)值及其對應的(de)(de)特(te)征(zheng)向(xiang)量，并將特(te)征(zheng)向(xiang)量經(jing)歸(gui)一化處理(li)后，即可得到相(xiang)應的(de)(de)層(ceng)(ceng)次(ci)單元排(pai)序的(de)(de)相(xiang)對重(zhong)要性權重(zhong)；最(zui)(zui)后，使用最(zui)(zui)大特(te)征(zheng)值和權重(zhong)向(xiang)量進行一致性檢驗，由(you)此計算出的(de)(de)各評價指(zhi)標(biao)(biao)的(de)(de)權重(zhong)值，見表3。

表3 污染(ran)場地(di)地(di)下水環境污染(ran)風(feng)險(xian)評價指(zhi)標的(de)權重值(zhi)

Table 3 Weight value of each risk evaluation index of groundwater pollution in contaminated site

2.3 評價指標分級與評分

污(wu)(wu)染(ran)源負荷評(ping)價(jia)指(zhi)標(biao)主要參考美(mei)國(guo)、加拿大等(deng)國(guo)家污(wu)(wu)染(ran)場地環境(jing)污(wu)(wu)染(ran)風(feng)險(xian)分(fen)(fen)級(ji)分(fen)(fen)類系統中(zhong)的(de)指(zhi)標(biao)分(fen)(fen)級(ji)；受體特征評(ping)價(jia)指(zhi)標(biao)主要參考我國(guo)《關閉(bi)搬遷(qian)企業地塊風(feng)險(xian)篩(shai)查與(yu)風(feng)險(xian)分(fen)(fen)級(ji)技(ji)術(shu)規(gui)定(試行)》中(zhong)的(de)指(zhi)標(biao)分(fen)(fen)級(ji)；污(wu)(wu)染(ran)物釋放可(ke)能性指(zhi)標(biao)主要參考DRASTIC及相關文獻[5,12]中(zhong)的(de)指(zhi)標(biao)分(fen)(fen)級(ji)。污(wu)(wu)染(ran)場地地下水環境(jing)污(wu)(wu)染(ran)風(feng)險(xian)各評(ping)價(jia)指(zhi)標(biao)的(de)分(fen)(fen)級(ji)與(yu)評(ping)分(fen)(fen)情(qing)況，見表(biao)4和表(biao)5。

表4 污(wu)染(ran)(ran)場地污(wu)染(ran)(ran)源負荷(he)和受(shou)體特征(zheng)評價指標(biao)分(fen)級(ji)與賦分(fen)表

Table 4 Classification and scores of source load indexes and acceptor charateristic indexes in contaminated site

表5 污染場地(di)污染物釋放可(ke)能性(xing)評價指標分級與賦分表

Table 5 Classification and scores of pollutant release potential indexes in contaminated site

3 案例應用與分析

3.1 污染場地概況與評分

1）建(jian)筑物豎向布置(zhi)：H1/H=34.5/98.4=0.35＞0.2；B1/B=17.5/39.5=0.0.44＜0.75。超限程度(du)：（0.75-0.44）/0.75×100%=41.3%。其中(zhong)，H1為(wei)1～9層裙房高度(du)；H為(wei)建(jian)筑物總高度(du)；B1為(wei)標準層寬(kuan)度(du)；B為(wei)裙房寬(kuan)度(du)。

案例一的(de)(de)某鉻鹽廠主(zhu)(zhu)要生產重鉻酸(suan)鈉(na)和(he)鉻酸(suan)酐等鉻系列產品，該(gai)(gai)(gai)(gai)污(wu)(wu)(wu)(wu)(wu)染場(chang)(chang)地(di)土(tu)壤(rang)中(zhong)主(zhu)(zhu)要特征(zheng)污(wu)(wu)(wu)(wu)(wu)染物(wu)為(wei)(wei)(wei)六價(jia)鉻(Cr6+)，由(you)《土(tu)壤(rang)環(huan)境(jing)質量 建(jian)設用(yong)(yong)(yong)地(di)土(tu)壤(rang)污(wu)(wu)(wu)(wu)(wu)染風(feng)險管控標(biao)(biao)(biao)準(試行(xing))》(GB 36600—2018)可(ke)(ke)知(zhi)，第二(er)類用(yong)(yong)(yong)地(di)土(tu)壤(rang)中(zhong)Cr6+的(de)(de)篩選(xuan)值(zhi)(zhi)為(wei)(wei)(wei)5.7 mg/kg，土(tu)壤(rang)中(zhong)Cr6+最(zui)大濃度值(zhi)(zhi)為(wei)(wei)(wei)811.57 mg/kg，按照公式(shi)(11)計算該(gai)(gai)(gai)(gai)污(wu)(wu)(wu)(wu)(wu)染場(chang)(chang)地(di)污(wu)(wu)(wu)(wu)(wu)染物(wu)Cr6+的(de)(de)超標(biao)(biao)(biao)倍數為(wei)(wei)(wei)142.38倍，污(wu)(wu)(wu)(wu)(wu)染場(chang)(chang)地(di)污(wu)(wu)(wu)(wu)(wu)染物(wu)Cr6+的(de)(de)超標(biao)(biao)(biao)范圍為(wei)(wei)(wei)2.98×104 m3；污(wu)(wu)(wu)(wu)(wu)染物(wu)釋(shi)放可(ke)(ke)能(neng)性各(ge)評價(jia)指(zhi)標(biao)(biao)(biao)根據該(gai)(gai)(gai)(gai)污(wu)(wu)(wu)(wu)(wu)染場(chang)(chang)地(di)實際(ji)調查(cha)報(bao)告取(qu)(qu)值(zhi)(zhi)，包括污(wu)(wu)(wu)(wu)(wu)染物(wu)分(fen)(fen)配(pei)系數、未(wei)污(wu)(wu)(wu)(wu)(wu)染土(tu)壤(rang)厚(hou)度、土(tu)壤(rang)水(shui)入滲速率、一階(jie)衰減常(chang)數和(he)土(tu)壤(rang)有機(ji)碳(tan)含量；該(gai)(gai)(gai)(gai)污(wu)(wu)(wu)(wu)(wu)染場(chang)(chang)地(di)地(di)下水(shui)利用(yong)(yong)(yong)類型為(wei)(wei)(wei)居民飲(yin)用(yong)(yong)(yong)水(shui)，場(chang)(chang)地(di)及周邊500 m內(nei)人口數量約為(wei)(wei)(wei)1 500人，場(chang)(chang)地(di)最(zui)近敏感點為(wei)(wei)(wei)地(di)表水(shui)，距場(chang)(chang)地(di)距離為(wei)(wei)(wei)50 m。按照表4和(he)表5中(zhong)各(ge)評價(jia)指(zhi)標(biao)(biao)(biao)的(de)(de)分(fen)(fen)級標(biao)(biao)(biao)準對該(gai)(gai)(gai)(gai)污(wu)(wu)(wu)(wu)(wu)染場(chang)(chang)地(di)各(ge)評價(jia)指(zhi)標(biao)(biao)(biao)進行(xing)評分(fen)(fen)，得到該(gai)(gai)(gai)(gai)污(wu)(wu)(wu)(wu)(wu)染場(chang)(chang)地(di)地(di)下水(shui)環(huan)境(jing)污(wu)(wu)(wu)(wu)(wu)染風(feng)險各(ge)評價(jia)指(zhi)標(biao)(biao)(biao)的(de)(de)取(qu)(qu)值(zhi)(zhi)及評分(fen)(fen)結果，見表6。

表6 案例一污(wu)染(ran)場地(di)地(di)下(xia)水(shui)環境污(wu)染(ran)風險評價指標評分(fen)結果(guo)

Table 6 Groundwater contamination risk score of case 1

案例二(er)的(de)(de)某化學原料和化學制品(pin)廠主(zhu)要生產色酚AS、間苯(ben)二(er)酚、滌綸樹脂等產品(pin)，污(wu)(wu)(wu)染(ran)(ran)(ran)主(zhu)要來源于加工過程中(zhong)原料、半(ban)成品(pin)、成品(pin)的(de)(de)污(wu)(wu)(wu)染(ran)(ran)(ran)，該(gai)污(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)(chang)地土(tu)壤中(zhong)主(zhu)要特(te)征污(wu)(wu)(wu)染(ran)(ran)(ran)物(wu)為(wei)苯(ben)、甲(jia)苯(ben)，土(tu)地利用(yong)類(lei)型(xing)為(wei)商業用(yong)地，由(you)《土(tu)壤環境質量 建設用(yong)地土(tu)壤污(wu)(wu)(wu)染(ran)(ran)(ran)風險管(guan)控標(biao)準(zhun)(試行)》(GB 36600—2018)可(ke)知(zhi)，第二(er)類(lei)用(yong)地土(tu)壤中(zhong)苯(ben)、甲(jia)苯(ben)的(de)(de)篩選(xuan)值分別為(wei)4 mg/kg、1 200 mg/kg，按照(zhao)公式(11)計算該(gai)污(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)(chang)地污(wu)(wu)(wu)染(ran)(ran)(ran)物(wu)的(de)(de)超(chao)標(biao)倍(bei)數(shu)為(wei)6 659倍(bei)，污(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)(chang)地污(wu)(wu)(wu)染(ran)(ran)(ran)物(wu)的(de)(de)超(chao)標(biao)范圍為(wei)1.35×104 m3；污(wu)(wu)(wu)染(ran)(ran)(ran)物(wu)釋(shi)放可(ke)能(neng)性評(ping)(ping)(ping)價指(zhi)標(biao)取值情況見表(biao)7；該(gai)污(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)(chang)地地下水利用(yong)類(lei)型(xing)為(wei)不開發，場(chang)(chang)(chang)地及周邊500 m內人口(kou)數(shu)量較(jiao)少，約為(wei)300人，最近敏感點(dian)為(wei)居民區，距場(chang)(chang)(chang)地距離(li)為(wei)400 m。按照(zhao)表(biao)4和表(biao)5中(zhong)各(ge)評(ping)(ping)(ping)價指(zhi)標(biao)的(de)(de)分級標(biao)準(zhun)對(dui)該(gai)污(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)(chang)地各(ge)評(ping)(ping)(ping)價指(zhi)標(biao)進行評(ping)(ping)(ping)分，得到該(gai)污(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)(chang)地地下水環境污(wu)(wu)(wu)染(ran)(ran)(ran)風險各(ge)評(ping)(ping)(ping)價指(zhi)標(biao)的(de)(de)取值及評(ping)(ping)(ping)分結果，見表(biao)7。

表7 案例(li)二污染場地地下水環(huan)境污染風險評價(jia)指標(biao)評分結果

Table 7 Groundwater contamination risk score of case 2

3.2 評價結果與分析

根據(ju)表(biao)6和表(biao)7中(zhong)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)各(ge)評(ping)(ping)價(jia)(jia)(jia)指(zhi)(zhi)標的(de)(de)(de)(de)(de)評(ping)(ping)分(fen)(fen)(fen)(fen)(fen)結果(guo)(guo)(guo)，按照公式(shi)(10)計算(suan)(suan)得(de)到兩個案(an)例(li)(li)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)地(di)(di)(di)(di)下水環(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)評(ping)(ping)價(jia)(jia)(jia)綜合指(zhi)(zhi)數(shu)總分(fen)(fen)(fen)(fen)(fen)值分(fen)(fen)(fen)(fen)(fen)別為(wei)(wei)9.08分(fen)(fen)(fen)(fen)(fen)、6.35分(fen)(fen)(fen)(fen)(fen)。此外，采用(yong)《關(guan)閉(bi)(bi)搬(ban)遷企業地(di)(di)(di)(di)塊風(feng)(feng)險(xian)(xian)篩(shai)查(cha)與風(feng)(feng)險(xian)(xian)分(fen)(fen)(fen)(fen)(fen)級(ji)技術規定(試(shi)(shi)行)》中(zhong)的(de)(de)(de)(de)(de)評(ping)(ping)價(jia)(jia)(jia)方法對其(qi)進行評(ping)(ping)價(jia)(jia)(jia)，計算(suan)(suan)得(de)到兩個案(an)例(li)(li)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)地(di)(di)(di)(di)下水環(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)評(ping)(ping)價(jia)(jia)(jia)總分(fen)(fen)(fen)(fen)(fen)值分(fen)(fen)(fen)(fen)(fen)別為(wei)(wei)84.4分(fen)(fen)(fen)(fen)(fen)、68.9分(fen)(fen)(fen)(fen)(fen)。結果(guo)(guo)(guo)表(biao)明：采用(yong)本文評(ping)(ping)價(jia)(jia)(jia)方法得(de)到案(an)例(li)(li)一(yi)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)為(wei)(wei)高污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)場(chang)(chang)(chang)地(di)(di)(di)(di)，案(an)例(li)(li)二污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)為(wei)(wei)中(zhong)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)場(chang)(chang)(chang)地(di)(di)(di)(di)。分(fen)(fen)(fen)(fen)(fen)析認為(wei)(wei)：案(an)例(li)(li)一(yi)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)生產活(huo)動時間較(jiao)長，多年粗(cu)放的(de)(de)(de)(de)(de)生產方式(shi)導致場(chang)(chang)(chang)地(di)(di)(di)(di)土壤污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)嚴重，污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)源負荷評(ping)(ping)價(jia)(jia)(jia)指(zhi)(zhi)標的(de)(de)(de)(de)(de)評(ping)(ping)分(fen)(fen)(fen)(fen)(fen)值較(jiao)高，且污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)距(ju)離居民生活(huo)區(qu)較(jiao)近，將會對周圍(wei)地(di)(di)(di)(di)下水和周邊人(ren)群健康造成(cheng)很大的(de)(de)(de)(de)(de)影響；案(an)例(li)(li)二污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)土壤污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)雖然(ran)較(jiao)為(wei)(wei)嚴重，但土壤中(zhong)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)物(wu)(wu)遷移能力較(jiao)弱，地(di)(di)(di)(di)下水為(wei)(wei)不利(li)用(yong)，敏感目(mu)標較(jiao)少，故該污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)地(di)(di)(di)(di)下水環(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)的(de)(de)(de)(de)(de)風(feng)(feng)險(xian)(xian)較(jiao)小。該評(ping)(ping)價(jia)(jia)(jia)結果(guo)(guo)(guo)與采用(yong)《關(guan)閉(bi)(bi)搬(ban)遷企業地(di)(di)(di)(di)塊風(feng)(feng)險(xian)(xian)篩(shai)查(cha)與風(feng)(feng)險(xian)(xian)分(fen)(fen)(fen)(fen)(fen)級(ji)技術規定(試(shi)(shi)行)》中(zhong)評(ping)(ping)價(jia)(jia)(jia)方法的(de)(de)(de)(de)(de)評(ping)(ping)價(jia)(jia)(jia)結果(guo)(guo)(guo)基本一(yi)致。另外，本文評(ping)(ping)介方法所選(xuan)取的(de)(de)(de)(de)(de)評(ping)(ping)價(jia)(jia)(jia)指(zhi)(zhi)標包括(kuo)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)物(wu)(wu)本身(shen)屬性的(de)(de)(de)(de)(de)指(zhi)(zhi)標如污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)物(wu)(wu)分(fen)(fen)(fen)(fen)(fen)配系(xi)數(shu)、一(yi)階衰(shuai)減(jian)常數(shu)等(deng)，適用(yong)于(yu)不同特(te)征(zheng)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)物(wu)(wu)場(chang)(chang)(chang)地(di)(di)(di)(di)地(di)(di)(di)(di)下水環(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)的(de)(de)(de)(de)(de)風(feng)(feng)險(xian)(xian)評(ping)(ping)價(jia)(jia)(jia)，并且可有效地(di)(di)(di)(di)減(jian)少評(ping)(ping)價(jia)(jia)(jia)過程中(zhong)的(de)(de)(de)(de)(de)主觀性，從而驗證了(le)本文所構建(jian)的(de)(de)(de)(de)(de)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)場(chang)(chang)(chang)地(di)(di)(di)(di)地(di)(di)(di)(di)下水環(huan)境(jing)(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)(ran)(ran)風(feng)(feng)險(xian)(xian)分(fen)(fen)(fen)(fen)(fen)析評(ping)(ping)價(jia)(jia)(jia)方法具有合理性和可靠性。

4 結論與建議

(1) 本(ben)文(wen)綜合考慮污染(ran)源負(fu)荷(he)、污染(ran)物(wu)釋放可(ke)能性(xing)、受體(ti)特征(zheng)三(san)個方(fang)面(mian)的(de)因素，采(cai)用層次(ci)分析(xi)法和靈敏度分析(xi)法構建了(le)污染(ran)場地(di)地(di)下(xia)水(shui)環境污染(ran)風險分級評(ping)價(jia)方(fang)法，有效降低了(le)建立評(ping)價(jia)指標體(ti)系時的(de)主觀性(xing)，可(ke)為(wei)環境管(guan)理部門提供理論依據及技術(shu)支撐。

(2) 運(yun)用本(ben)文所構建的(de)(de)污(wu)(wu)(wu)染(ran)(ran)場(chang)(chang)(chang)地(di)(di)地(di)(di)下(xia)(xia)水環(huan)境污(wu)(wu)(wu)染(ran)(ran)風(feng)險分級評(ping)價(jia)(jia)方法(fa)(fa)(fa)對兩個典型案例(li)污(wu)(wu)(wu)染(ran)(ran)場(chang)(chang)(chang)地(di)(di)地(di)(di)下(xia)(xia)水環(huan)境污(wu)(wu)(wu)染(ran)(ran)風(feng)險進行了分級評(ping)價(jia)(jia)與驗證(zheng)(zheng)，結果表明：案例(li)一(yi)污(wu)(wu)(wu)染(ran)(ran)場(chang)(chang)(chang)地(di)(di)為(wei)高污(wu)(wu)(wu)染(ran)(ran)風(feng)險場(chang)(chang)(chang)地(di)(di)，案例(li)二(er)污(wu)(wu)(wu)染(ran)(ran)場(chang)(chang)(chang)地(di)(di)為(wei)中(zhong)污(wu)(wu)(wu)染(ran)(ran)風(feng)險場(chang)(chang)(chang)地(di)(di)，該評(ping)價(jia)(jia)結果與現有(you)評(ping)價(jia)(jia)方法(fa)(fa)(fa)的(de)(de)評(ping)價(jia)(jia)結果基本(ben)一(yi)致，且本(ben)文構建的(de)(de)評(ping)價(jia)(jia)方法(fa)(fa)(fa)更(geng)適用于不同特征(zheng)污(wu)(wu)(wu)染(ran)(ran)物(wu)場(chang)(chang)(chang)地(di)(di)的(de)(de)地(di)(di)下(xia)(xia)水環(huan)境污(wu)(wu)(wu)染(ran)(ran)風(feng)險分級評(ping)價(jia)(jia)，從而(er)驗證(zheng)(zheng)了本(ben)文所構建的(de)(de)評(ping)價(jia)(jia)方法(fa)(fa)(fa)具有(you)合理(li)性和可靠性。

(3) 污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)地(di)環(huan)境(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)風(feng)(feng)險(xian)的分(fen)(fen)級評(ping)價(jia)可(ke)以根據污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)地(di)環(huan)境(jing)(jing)危(wei)害的輕重緩急進(jin)行(xing)優先區分(fen)(fen)，以便對不同風(feng)(feng)險(xian)等級的污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)地(di)進(jin)行(xing)分(fen)(fen)類(lei)管理。國(guo)家層(ceng)面的污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)地(di)環(huan)境(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)風(feng)(feng)險(xian)分(fen)(fen)級分(fen)(fen)類(lei)評(ping)價(jia)體系(xi)(xi)的構(gou)建(jian)是一(yi)項長期而復(fu)雜的系(xi)(xi)統(tong)工程，建(jian)議借鑒國(guo)外發(fa)達(da)國(guo)家已有的污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)地(di)環(huan)境(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)風(feng)(feng)險(xian)分(fen)(fen)級分(fen)(fen)類(lei)評(ping)價(jia)體系(xi)(xi)，采用多(duo)種評(ping)價(jia)方(fang)法，并從(cong)多(duo)途徑(jing)、多(duo)受體、多(duo)方(fang)面構(gou)建(jian)綜合(he)、全面、系(xi)(xi)統(tong)的污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)場(chang)(chang)地(di)環(huan)境(jing)(jing)污(wu)(wu)(wu)(wu)染(ran)(ran)(ran)風(feng)(feng)險(xian)分(fen)(fen)級管理體系(xi)(xi)。

來源：土行者