摘(zhai)要：為揭示太湖(hu)(hu)東(dong)部疏(shu)(shu)浚湖(hu)(hu)區沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)中(zhong)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)分布特(te)征(zheng)及其(qi)潛(qian)在(zai)(zai)生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)風(feng)險(xian)(xian)(xian)(xian)，于(yu)2012年在(zai)(zai)東(dong)太湖(hu)(hu)與胥(xu)口(kou)灣(wan)共設置5個點位(wei)采集(ji)沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)樣品(pin)，測試了底泥(ni)部分理化性質及重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)元(yuan)素(su)(su)含量(liang)（As、Cd、Cr、Cu、Hg、Ni、Pb、Zn），并運用潛(qian)在(zai)(zai)生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)風(feng)險(xian)(xian)(xian)(xian)指數法綜合評(ping)價(jia)(jia)了疏(shu)(shu)浚湖(hu)(hu)區沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)的(de)(de)(de)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)污(wu)(wu)染(ran)現(xian)(xian)狀(zhuang)和(he)潛(qian)在(zai)(zai)風(feng)險(xian)(xian)(xian)(xian)程(cheng)度。結果表(biao)明(ming)(ming)，太湖(hu)(hu)東(dong)部不同類型湖(hu)(hu)區間沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)的(de)(de)(de)營(ying)(ying)養鹽及重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)含量(liang)分布存在(zai)(zai)差異，總體上(shang)胥(xu)口(kou)灣(wan)草型湖(hu)(hu)區的(de)(de)(de)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)含量(liang)相對東(dong)太湖(hu)(hu)養殖湖(hu)(hu)區較高，營(ying)(ying)養鹽含量(liang)則(ze)相對較低；在(zai)(zai)垂直剖面上(shang)，沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)營(ying)(ying)養鹽和(he)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)均(jun)表(biao)現(xian)(xian)出表(biao)層富集(ji)的(de)(de)(de)特(te)征(zheng)。太湖(hu)(hu)東(dong)部湖(hu)(hu)區各疏(shu)(shu)浚點位(wei)的(de)(de)(de)營(ying)(ying)養鹽和(he)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)含量(liang)均(jun)低于(yu)未疏(shu)(shu)浚點位(wei)，表(biao)明(ming)(ming)底泥(ni)生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)疏(shu)(shu)浚能(neng)有(you)效(xiao)去除沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)中(zhong)的(de)(de)(de)營(ying)(ying)養物(wu)(wu)(wu)(wu)質和(he)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)污(wu)(wu)染(ran)物(wu)(wu)(wu)(wu)，但疏(shu)(shu)浚效(xiao)果隨時間逐漸減弱(ruo)。各重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)元(yuan)素(su)(su)及營(ying)(ying)養鹽之間均(jun)呈顯著(zhu)正相關(guan)(guan)關(guan)(guan)系，表(biao)明(ming)(ming)這些污(wu)(wu)染(ran)物(wu)(wu)(wu)(wu)具有(you)較好的(de)(de)(de)同源性。潛(qian)在(zai)(zai)生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)風(feng)險(xian)(xian)(xian)(xian)指數RI的(de)(de)(de)評(ping)價(jia)(jia)結果表(biao)明(ming)(ming)，各點位(wei)沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)的(de)(de)(de)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)潛(qian)在(zai)(zai)危害(hai)程(cheng)度依次為X1>D1>D3>X2>D2，其(qi)中(zhong)未疏(shu)(shu)浚點位(wei)胥(xu)口(kou)灣(wan)X1的(de)(de)(de)潛(qian)在(zai)(zai)生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)風(feng)險(xian)(xian)(xian)(xian)高于(yu)東(dong)太湖(hu)(hu)D1，且(qie)X1、D1均(jun)屬(shu)(shu)(shu)(shu)于(yu)中(zhong)等生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)風(feng)險(xian)(xian)(xian)(xian)，而疏(shu)(shu)浚點位(wei)D2、D3、X2屬(shu)(shu)(shu)(shu)于(yu)輕微(wei)生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)風(feng)險(xian)(xian)(xian)(xian)，底泥(ni)疏(shu)(shu)浚有(you)效(xiao)降低了沉(chen)(chen)(chen)積(ji)物(wu)(wu)(wu)(wu)中(zhong)的(de)(de)(de)重(zhong)(zhong)(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)(shu)潛(qian)在(zai)(zai)生(sheng)(sheng)(sheng)(sheng)態(tai)(tai)(tai)風(feng)險(xian)(xian)(xian)(xian)。

關鍵詞：底泥疏浚，營養鹽，重金(jin)屬，潛(qian)在(zai)生態(tai)風險(xian)評價，太湖(hu)

太(tai)湖作為(wei)我國第三大淡水(shui)(shui)湖泊，在(zai)整個流(liu)域的洪澇控制、水(shui)(shui)資源供(gong)應、漁(yu)業及旅游等方面(mian)都(dou)發揮著重(zhong)(zhong)要作用。但自1980年代以來，太(tai)湖流(liu)域經(jing)濟快速(su)(su)發展，未經(jing)處理的工農業及城市(shi)生活(huo)污水(shui)(shui)排入湖體，大量營養物(wu)質及有毒重(zhong)(zhong)金屬污染物(wu)在(zai)底泥(ni)(ni)中不斷積(ji)累。其中太(tai)湖東(dong)(dong)部湖區是周邊城市(shi)最(zui)重(zhong)(zhong)要的飲(yin)用水(shui)(shui)源地(di)，包含貢湖、胥(xu)口(kou)(kou)灣(wan)、東(dong)(dong)太(tai)湖等湖灣(wan)，共9個取水(shui)(shui)口(kou)(kou)，太(tai)湖整體水(shui)(shui)質的迅(xun)速(su)(su)惡化(hua)及底泥(ni)(ni)中重(zhong)(zhong)金屬污染程度(du)的加重(zhong)(zhong)對東(dong)(dong)部湖區的水(shui)(shui)質安全構成(cheng)威脅。

重(zhong)金(jin)(jin)屬(shu)作為典型的(de)(de)累積性污染(ran)物，其顯著的(de)(de)生物毒(du)性和持久性，對(dui)生態環(huan)境構成潛在威(wei)脅(xie)。對(dui)湖泊(bo)環(huan)境而(er)言，底泥不但是重(zhong)金(jin)(jin)屬(shu)遷移轉化的(de)(de)主(zhu)要歸宿，同時在外界條件適宜時，底泥中(zhong)的(de)(de)重(zhong)金(jin)(jin)屬(shu)會重(zhong)新釋(shi)放進入水體(ti)，并造成二次污染(ran)。因此，如果能有效控制或去除沉積物中(zhong)潛在的(de)(de)重(zhong)金(jin)(jin)屬(shu)內(nei)源污染(ran)，將(jiang)對(dui)湖泊(bo)整體(ti)環(huan)境治(zhi)理與(yu)水體(ti)質量改善具有重(zhong)

大意義。目前，底(di)泥(ni)疏(shu)(shu)(shu)(shu)竣(jun)作為一(yi)(yi)種去除重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)污(wu)染物(wu)(wu)(wu)的(de)(de)(de)(de)湖(hu)泊治理(li)方法已經被廣泛(fan)運用于(yu)世界各地(di)的(de)(de)(de)(de)水(shui)(shui)環(huan)境(jing)(jing)治理(li)工程(cheng)中。通(tong)過生(sheng)態(tai)疏(shu)(shu)(shu)(shu)浚(jun)(jun)可以(yi)將污(wu)染物(wu)(wu)(wu)移(yi)出(chu)湖(hu)體(ti)，減輕底(di)泥(ni)中重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)對(dui)水(shui)(shui)生(sheng)生(sheng)物(wu)(wu)(wu)的(de)(de)(de)(de)毒性威脅，并達到改善(shan)水(shui)(shui)環(huan)境(jing)(jing)質(zhi)量的(de)(de)(de)(de)目的(de)(de)(de)(de)。因此，太(tai)(tai)湖(hu)東(dong)(dong)部(bu)湖(hu)區(qu)也開展(zhan)了(le)一(yi)(yi)系列的(de)(de)(de)(de)底(di)泥(ni)疏(shu)(shu)(shu)(shu)浚(jun)(jun)工程(cheng)，包括(kuo)胥口灣(wan)水(shui)(shui)源地(di)生(sheng)態(tai)清淤(yu)和(he)東(dong)(dong)太(tai)(tai)湖(hu)航道疏(shu)(shu)(shu)(shu)浚(jun)(jun)工程(cheng)等。但(dan)是，由于(yu)湖(hu)泊底(di)泥(ni)疏(shu)(shu)(shu)(shu)浚(jun)(jun)可能會引起(qi)營(ying)養(yang)鹽和(he)重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)等有毒物(wu)(wu)(wu)質(zhi)的(de)(de)(de)(de)釋(shi)放，一(yi)(yi)些研(yan)(yan)究(jiu)(jiu)(jiu)者也對(dui)疏(shu)(shu)(shu)(shu)浚(jun)(jun)的(de)(de)(de)(de)治理(li)效(xiao)果和(he)環(huan)境(jing)(jing)效(xiao)應提出(chu)了(le)置疑。關(guan)于(yu)太(tai)(tai)湖(hu)底(di)泥(ni)疏(shu)(shu)(shu)(shu)浚(jun)(jun)對(dui)營(ying)養(yang)鹽和(he)重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)釋(shi)放的(de)(de)(de)(de)影響已有一(yi)(yi)些報道，王(wang)棟等研(yan)(yan)究(jiu)(jiu)(jiu)表明疏(shu)(shu)(shu)(shu)浚(jun)(jun)導致的(de)(de)(de)(de)底(di)泥(ni)重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)釋(shi)放在短期(qi)(qi)內可能會對(dui)水(shui)(shui)體(ti)環(huan)境(jing)(jing)造成(cheng)一(yi)(yi)定程(cheng)度的(de)(de)(de)(de)生(sheng)態(tai)壓力，而鐘繼承等則發現(xian)底(di)泥(ni)疏(shu)(shu)(shu)(shu)浚(jun)(jun)是消減沉積(ji)物(wu)(wu)(wu)內源磷負荷的(de)(de)(de)(de)有效(xiao)手段。這些研(yan)(yan)究(jiu)(jiu)(jiu)主要關(guan)注于(yu)底(di)泥(ni)疏(shu)(shu)(shu)(shu)浚(jun)(jun)的(de)(de)(de)(de)短期(qi)(qi)效(xiao)應分(fen)析，對(dui)于(yu)疏(shu)(shu)(shu)(shu)浚(jun)(jun)后(hou)的(de)(de)(de)(de)長期(qi)(qi)生(sheng)態(tai)效(xiao)應關(guan)注較小，且研(yan)(yan)究(jiu)(jiu)(jiu)區(qu)域集(ji)中在太(tai)(tai)湖(hu)污(wu)染較為嚴(yan)重(zhong)的(de)(de)(de)(de)北部(bu)湖(hu)區(qu)。因此，本研(yan)(yan)究(jiu)(jiu)(jiu)將結合太(tai)(tai)湖(hu)東(dong)(dong)部(bu)湖(hu)區(qu)的(de)(de)(de)(de)生(sheng)態(tai)疏(shu)(shu)(shu)(shu)浚(jun)(jun)工程(cheng)，在分(fen)析不同類型湖(hu)灣(wan)疏(shu)(shu)(shu)(shu)浚(jun)(jun)后(hou)底(di)泥(ni)營(ying)養(yang)鹽與重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)空(kong)間分(fen)布規(gui)律的(de)(de)(de)(de)基礎上，評價(jia)沉積(ji)物(wu)(wu)(wu)中重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)的(de)(de)(de)(de)污(wu)染現(xian)狀和(he)潛在生(sheng)態(tai)風險程(cheng)度，旨在為太(tai)(tai)湖(hu)重(zhong)金(jin)(jin)(jin)屬(shu)(shu)(shu)的(de)(de)(de)(de)污(wu)染防治及水(shui)(shui)源地(di)的(de)(de)(de)(de)水(shui)(shui)質(zhi)安全提供科學依據。

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