常紀文:海水淡化規模化利用問題與建議
【谷騰環保網訊】鑒于海(hai)(hai)島海(hai)(hai)水淡化(hua)(hua)有較好(hao)的(de)經濟性,近期(qi)有相關(guan)(guan)人士呼吁將(jiang)海(hai)(hai)水淡化(hua)(hua)水作為新水源(yuan)納入國家(jia)水網工程。“十四五”期(qi)間(jian),我(wo)國僅海(hai)(hai)島地區就(jiu)規劃新增(zeng)海(hai)(hai)水淡化(hua)(hua)規模20萬t/d以上。有必(bi)要(yao)針對海(hai)(hai)水淡化(hua)(hua)規模化(hua)(hua)利用存在的(de)現實問題,完善相關(guan)(guan)的(de)政(zheng)策要(yao)求。
我國沿(yan)海(hai)(hai)地區水(shui)(shui)(shui)資源供需(xu)矛盾突(tu)出,制約了經濟社會的(de)發展。沿(yan)海(hai)(hai)11個(ge)省(自(zi)治區、直轄市)水(shui)(shui)(shui)資源總量僅占全(quan)國的(de)27%,卻創造了55%的(de)國內生(sheng)產總值。區域內55個(ge)沿(yan)海(hai)(hai)地級以上城(cheng)市中有51個(ge)為缺水(shui)(shui)(shui)城(cheng)市,12個(ge)海(hai)(hai)島縣全(quan)部為缺水(shui)(shui)(shui)縣。海(hai)(hai)水(shui)(shui)(shui)淡化是(shi)重要的(de)增量水(shui)(shui)(shui)源,對緩解(jie)沿(yan)海(hai)(hai)地區和海(hai)(hai)島水(shui)(shui)(shui)資源短缺,保障水(shui)(shui)(shui)安全(quan)具有重要意義。
海水(shui)淡化發展概況
2010年(nian)以來,我國針對海水淡化行業先后設(she)立了“十二五(wu)”至“十四五(wu)”三個階段的發展目標,出臺多項(xiang)支(zhi)持政策,大力推動行業發展。
“十二五”時期,我國(guo)海水(shui)(shui)淡(dan)化(hua)行業尚處(chu)于(yu)初步發展(zhan)階段,國(guo)家政策從(cong)基(ji)礎規(gui)劃入手,先后出臺了《關于(yu)加快發展(zhan)海水(shui)(shui)淡(dan)化(hua)產業的意見》《海水(shui)(shui)淡(dan)化(hua)產業發展(zhan)“十二五”規(gui)劃》《海水(shui)(shui)淡(dan)化(hua)科技發展(zhan)“十二五”專項(xiang)規(gui)劃》等文(wen)件,指導海水(shui)(shui)淡(dan)化(hua)技術創新體系的建(jian)立。
“十三五”時期,為推動海(hai)(hai)水淡化產(chan)(chan)業(ye)向規(gui)(gui)模(mo)化、集成(cheng)化方向發(fa)展,國家(jia)發(fa)展改革(ge)委和國家(jia)海(hai)(hai)洋局共同印發(fa)了《全(quan)國海(hai)(hai)水利用“十三五”規(gui)(gui)劃(hua)》,海(hai)(hai)水淡化成(cheng)為我國戰(zhan)略性新(xin)興產(chan)(chan)業(ye)。
“十四五”以來,國(guo)家政(zheng)策更加(jia)側(ce)重應用,國(guo)家發展改革委和(he)自然資源部(bu)聯合印發了《海(hai)水淡化利(li)用發展行動計劃(2021—2025年(nian))》,以推(tui)動海(hai)水淡化的規模化利(li)用。
海(hai)水(shui)(shui)(shui)淡(dan)(dan)化(hua)已(yi)在全球范圍內(nei)得到大規模利用。海(hai)水(shui)(shui)(shui)淡(dan)(dan)化(hua)水(shui)(shui)(shui)用于(yu)市政(zheng)供水(shui)(shui)(shui)已(yi)有60余年(nian)歷史,160多個國(guo)家(jia)的(de)(de)約3億(yi)人長(chang)(chang)期飲用海(hai)水(shui)(shui)(shui)淡(dan)(dan)化(hua)水(shui)(shui)(shui)。全球海(hai)水(shui)(shui)(shui)淡(dan)(dan)化(hua)產(chan)能從2000年(nian)的(de)(de)不足3000萬t/d增長(chang)(chang)到2020年(nian)的(de)(de)1億(yi)t/d,年(nian)均增幅超過7%。海(hai)水(shui)(shui)(shui)淡(dan)(dan)化(hua)成本從20世紀(ji)70年(nian)代(dai)的(de)(de)10美元/t降至目前(qian)不足1美元/t,經濟上(shang)逐(zhu)漸可行。
我國(guo)目前已建(jian)(jian)成海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)工程123個,海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)能力超過(guo)160萬(wan)(wan)(wan)t/d。根據(ju)《海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)利用(yong)(yong)發(fa)展行動計劃(2021—2025年)》,到2025年,我國(guo)海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)總(zong)規模將達到290萬(wan)(wan)(wan)t/d以上(shang),新(xin)增(zeng)海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)規模125萬(wan)(wan)(wan)t/d以上(shang),其中(zhong)沿海(hai)(hai)城(cheng)市新(xin)增(zeng)海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)規模105萬(wan)(wan)(wan)t/d以上(shang),海(hai)(hai)島(dao)地(di)區(qu)新(xin)增(zeng)海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)規模20萬(wan)(wan)(wan)t/d以上(shang)。該計劃要求(qiu)沿海(hai)(hai)缺水(shui)(shui)(shui)地(di)區(qu)將海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)水(shui)(shui)(shui)作為生活補充水(shui)(shui)(shui)源(yuan)、市政新(xin)增(zeng)供水(shui)(shui)(shui)及(ji)重要應急(ji)備用(yong)(yong)水(shui)(shui)(shui)源(yuan),逐年提高海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)水(shui)(shui)(shui)在(zai)水(shui)(shui)(shui)資源(yuan)中(zhong)的配置比例;在(zai)海(hai)(hai)島(dao)保護性開(kai)發(fa)基(ji)礎上(shang),適度超前布局建(jian)(jian)設海(hai)(hai)島(dao)海(hai)(hai)水(shui)(shui)(shui)淡(dan)化(hua)(hua)設施,滿足生產(chan)生活生態用(yong)(yong)水(shui)(shui)(shui)需(xu)求(qiu)。
海水淡(dan)化規模化利用存在的潛在風險
目(mu)前我國(guo)還未(wei)建成(cheng)海(hai)水(shui)(shui)淡(dan)化(hua)相關的國(guo)家標(biao)準(zhun)體(ti)系(xi)。由(you)于海(hai)水(shui)(shui)的特殊性,現(xian)(xian)有(you)的國(guo)家標(biao)準(zhun)難(nan)以(yi)解決生產、輸送、飲用(yong)過(guo)程中出(chu)現(xian)(xian)的各(ge)種(zhong)衛生安全(quan)問題。現(xian)(xian)有(you)的一些海(hai)水(shui)(shui)淡(dan)化(hua)行業標(biao)準(zhun)尚未(wei)得到衛生、水(shui)(shui)利等部門的認同。
1.水質(zhi)標(biao)準不健全
一是(shi)對作(zuo)為(wei)淡(dan)(dan)化水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)的(de)海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)質尚無明確標(biao)(biao)(biao)(biao)準(zhun)(zhun)。現(xian)行(xing)國家(jia)標(biao)(biao)(biao)(biao)準(zhun)(zhun)《生(sheng)(sheng)活(huo)(huo)飲用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)衛(wei)生(sheng)(sheng)標(biao)(biao)(biao)(biao)準(zhun)(zhun)》(GB 5749—2006)涵蓋106項(xiang)指(zhi)標(biao)(biao)(biao)(biao),僅規定了采用(yong)(yong)地表水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)或地下水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)為(wei)生(sheng)(sheng)活(huo)(huo)飲用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)時的(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)質衛(wei)生(sheng)(sheng)要(yao)求,未涉(she)及其(qi)他水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)。2022年(nian)(nian)3月(yue)《生(sheng)(sheng)活(huo)(huo)飲用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)衛(wei)生(sheng)(sheng)標(biao)(biao)(biao)(biao)準(zhun)(zhun)》(GB 5749—2022)發(fa)布,將于2023年(nian)(nian)4月(yue)1日(ri)起全部(bu)代替GB 5749—2006,新標(biao)(biao)(biao)(biao)準(zhun)(zhun)共涵蓋97項(xiang)指(zhi)標(biao)(biao)(biao)(biao)未將海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)(dan)化水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)作(zuo)為(wei)飲用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)。《海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)質標(biao)(biao)(biao)(biao)準(zhun)(zhun)》也未規定用(yong)(yong)作(zuo)海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)(dan)化水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)的(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)質要(yao)求,導致(zhi)將海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)(dan)化水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)用(yong)(yong)于飲用(yong)(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)缺乏(fa)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)源(yuan)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)(shui)質衛(wei)生(sheng)(sheng)標(biao)(biao)(biao)(biao)準(zhun)(zhun)。
二(er)是飲(yin)用(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)標(biao)準(zhun)(zhun)(zhun)不能(neng)明確判定海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)衛(wei)生(sheng)安(an)全性(xing)。全球現(xian)行各類(lei)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)標(biao)準(zhun)(zhun)(zhun)主(zhu)要針對(dui)地(di)下(xia)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)或地(di)表(biao)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)等常規水(shui)(shui)(shui)(shui)(shui)(shui)(shui)源,對(dui)海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)衛(wei)生(sheng)標(biao)準(zhun)(zhun)(zhun)總體上處于“憑經驗”摸索階段。2011年(nian)(nian)(nian),世界衛(wei)生(sheng)組織(WHO)在(zai)《飲(yin)用(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)準(zhun)(zhun)(zhun)則》(第四(si)版,水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)指(zhi)標(biao)237項)中特別指(zhi)出(chu),現(xian)行的(de)飲(yin)用(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)準(zhun)(zhun)(zhun)則不能(neng)涵蓋淡(dan)化(hua)(hua)(hua)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)的(de)全部方面(mian),需關(guan)(guan)注其(qi)可(ke)(ke)能(neng)產生(sheng)的(de)化(hua)(hua)(hua)學性(xing)污染和生(sheng)物(wu)性(xing)污染。2006年(nian)(nian)(nian)WHO出(chu)臺的(de)《海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)飲(yin)用(yong)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)發展指(zhi)南》介紹了海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)可(ke)(ke)能(neng)存(cun)在(zai)的(de)問(wen)題,并在(zai)2007年(nian)(nian)(nian)和2011年(nian)(nian)(nian)公布了更加(jia)詳盡(jin)的(de)指(zhi)南,全面(mian)介紹了海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)可(ke)(ke)能(neng)帶來的(de)健(jian)康問(wen)題及環境(jing)問(wen)題。2021年(nian)(nian)(nian)9月29日,國際標(biao)準(zhun)(zhun)(zhun)化(hua)(hua)(hua)組織(ISO)發布《海洋技(ji)術—反滲透(tou)(tou)海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)產品(pin)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)—市政供水(shui)(shui)(shui)(shui)(shui)(shui)(shui)指(zhi)南》,這是首項由(you)我國主(zhu)導的(de)ISO海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)領域(yu)國際標(biao)準(zhun)(zhun)(zhun),指(zhi)南規范(fan)了飲(yin)用(yong)反滲透(tou)(tou)海水(shui)(shui)(shui)(shui)(shui)(shui)(shui)淡(dan)化(hua)(hua)(hua)水(shui)(shui)(shui)(shui)(shui)(shui)(shui)關(guan)(guan)鍵水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)參數及其(qi)范(fan)圍、監測頻率和測試方法。但該標(biao)準(zhun)(zhun)(zhun)能(neng)否得到水(shui)(shui)(shui)(shui)(shui)(shui)(shui)質(zhi)衛(wei)生(sheng)主(zhu)管(guan)部門認(ren)可(ke)(ke),還需要實(shi)踐的(de)檢驗。
三是(shi)現有放(fang)(fang)射(she)性(xing)(xing)(xing)指標(biao)只能(neng)起(qi)到初(chu)篩(shai)作用(yong),且(qie)國內(nei)標(biao)準(zhun)偏低。現行《生(sheng)(sheng)活飲用(yong)水衛生(sheng)(sheng)標(biao)準(zhun)》中放(fang)(fang)射(she)性(xing)(xing)(xing)指標(biao)只有總(zong)α放(fang)(fang)射(she)性(xing)(xing)(xing)、總(zong)β放(fang)(fang)射(she)性(xing)(xing)(xing)兩項,僅(jin)能(neng)作為(wei)(wei)飲用(yong)水放(fang)(fang)射(she)性(xing)(xing)(xing)初(chu)篩(shai)指標(biao),即低于此值的(de)水可認(ren)為(wei)(wei)是(shi)適(shi)合飲用(yong)的(de),高(gao)于該值并(bing)不說明不適(shi)合生(sheng)(sheng)活飲用(yong),應進行放(fang)(fang)射(she)性(xing)(xing)(xing)核素分析,估算所致劑量,作出衛生(sheng)(sheng)學評價。WHO的(de)推薦(jian)值是(shi)總(zong)α放(fang)(fang)射(she)性(xing)(xing)(xing)為(wei)(wei)0.1Bq/L,總(zong)β放(fang)(fang)射(she)性(xing)(xing)(xing)為(wei)(wei)1Bq/L,而我國現行《生(sheng)(sheng)活飲用(yong)水衛生(sheng)(sheng)標(biao)準(zhun)》規定的(de)總(zong)α放(fang)(fang)射(she)性(xing)(xing)(xing)限值為(wei)(wei)0.5Bq/L,總(zong)β放(fang)(fang)射(she)性(xing)(xing)(xing)限值為(wei)(wei)1Bq/L,總(zong)α放(fang)(fang)射(she)性(xing)(xing)(xing)限值明顯高(gao)于WHO的(de)推薦(jian)值。
四是《生(sheng)活飲(yin)(yin)用水(shui)(shui)(shui)(shui)衛生(sheng)標準(zhun)》中水(shui)(shui)(shui)(shui)質(zhi)(zhi)指標沒有下限值,不能直接套用于海(hai)(hai)(hai)水(shui)(shui)(shui)(shui)淡(dan)(dan)化(hua)(hua)水(shui)(shui)(shui)(shui),無法(fa)滿足規模(mo)化(hua)(hua)生(sheng)產(chan)所需的(de)質(zhi)(zhi)控要求(qiu)。2010年,歐洲議會和歐洲理事會在(zai)《關(guan)于海(hai)(hai)(hai)水(shui)(shui)(shui)(shui)淡(dan)(dan)化(hua)(hua)條例(li)的(de)導則》中分析了海(hai)(hai)(hai)水(shui)(shui)(shui)(shui)淡(dan)(dan)化(hua)(hua)的(de)健康(kang)、環境及(ji)政策問(wen)題(ti),指出海(hai)(hai)(hai)水(shui)(shui)(shui)(shui)淡(dan)(dan)化(hua)(hua)水(shui)(shui)(shui)(shui)水(shui)(shui)(shui)(shui)質(zhi)(zhi)指南(nan)應(ying)設定鈣(gai)、鎂離子的(de)最低含量。由于我(wo)國目前以(yi)(yi)地表水(shui)(shui)(shui)(shui)或地下水(shui)(shui)(shui)(shui)為原水(shui)(shui)(shui)(shui)的(de)生(sheng)活飲(yin)(yin)用水(shui)(shui)(shui)(shui)衛生(sheng)標準(zhun)對水(shui)(shui)(shui)(shui)的(de)硬度以(yi)(yi)及(ji)所有的(de)礦(kuang)物質(zhi)(zhi)和化(hua)(hua)學元素未(wei)設定下限值,故無法(fa)對海(hai)(hai)(hai)水(shui)(shui)(shui)(shui)淡(dan)(dan)化(hua)(hua)水(shui)(shui)(shui)(shui)的(de)水(shui)(shui)(shui)(shui)質(zhi)(zhi)衛生(sheng)進行評價和監(jian)督,導致海(hai)(hai)(hai)水(shui)(shui)(shui)(shui)淡(dan)(dan)化(hua)(hua)水(shui)(shui)(shui)(shui)的(de)水(shui)(shui)(shui)(shui)質(zhi)(zhi)衛生(sheng)安(an)全性難以(yi)(yi)得到(dao)保障,限制了規模(mo)化(hua)(hua)生(sheng)產(chan)。
2.長(chang)期(qi)飲用(yong)存在潛在風(feng)險
海(hai)水(shui)(shui)淡化可去除部(bu)分有害物質(zhi),無論原水(shui)(shui)水(shui)(shui)質(zhi)、處理方式、產品水(shui)(shui)水(shui)(shui)質(zhi),與傳統以地(di)表水(shui)(shui)或地(di)下水(shui)(shui)為(wei)水(shui)(shui)源的飲用水(shui)(shui)都有很大的差(cha)異,長期飲用存在(zai)潛在(zai)風險。
一是(shi)有(you)害成分(fen)偏(pian)高(gao),有(you)益成分(fen)過低。一方(fang)面(mian),島(dao)礁和船舶反(fan)滲透(tou)海水(shui)(shui)淡化對(dui)于(yu)硼(peng)(peng)的(de)截留率(lv)效率(lv)有(you)限,水(shui)(shui)中硼(peng)(peng)濃(nong)(nong)度(du)(du)往(wang)往(wang)比較高(gao),通常(chang)會高(gao)于(yu)0.5mg/L。0.5mg/L是(shi)《生活(huo)飲(yin)用(yong)水(shui)(shui)衛生標準(zhun)》(GB 5749—2006)規定(ding)的(de)硼(peng)(peng)濃(nong)(nong)度(du)(du)限值,《生活(huo)飲(yin)用(yong)水(shui)(shui)衛生標準(zhun)》(GB 5749—2022)將該(gai)限值修改為1.0mg/L,WHO《飲(yin)用(yong)水(shui)(shui)水(shui)(shui)質(zhi)準(zhun)則》規定(ding)的(de)準(zhun)則值為2.4mg/L,但在世界大(da)多(duo)數(shu)國家和地區,飲(yin)用(yong)水(shui)(shui)中硼(peng)(peng)的(de)濃(nong)(nong)度(du)(du)多(duo)低于(yu)0.5mg/L。但對(dui)于(yu)有(you)些地方(fang)而言,即使經過二級反(fan)滲透(tou)處(chu)理,水(shui)(shui)中硼(peng)(peng)的(de)含量仍然還有(you)1~2mg/L,長(chang)期(qi)飲(yin)用(yong)高(gao)硼(peng)(peng)水(shui)(shui)可能產生不(bu)(bu)良影(ying)響。另一方(fang)面(mian),鈣、鎂、硫酸鹽(yan)、重碳酸鹽(yan)、氟等成分(fen)濃(nong)(nong)度(du)(du)往(wang)往(wang)低于(yu)《低礦(kuang)化度(du)(du)飲(yin)用(yong)水(shui)(shui)礦(kuang)化衛生標準(zhun)》(GJB 1335—92)要求的(de)濃(nong)(nong)度(du)(du)范圍,屬于(yu)典型的(de)軟水(shui)(shui),長(chang)期(qi)飲(yin)用(yong)對(dui)人體(ti)健康(kang)不(bu)(bu)利。
二(er)是(shi)海島居民(min)長期飲用海水(shui)(shui)(shui)淡(dan)(dan)(dan)化(hua)水(shui)(shui)(shui),患(huan)某些(xie)慢(man)性(xing)(xing)病(bing)的(de)(de)風險更大。浙江省舟山市疾病(bing)預防控制(zhi)中(zhong)心和(he)嵊(sheng)泗縣疾病(bing)預防控制(zhi)中(zhong)心曾以飲用海水(shui)(shui)(shui)淡(dan)(dan)(dan)化(hua)水(shui)(shui)(shui)的(de)(de)居民(min)為淡(dan)(dan)(dan)化(hua)水(shui)(shui)(shui)觀(guan)察組,飲用海水(shui)(shui)(shui)淡(dan)(dan)(dan)化(hua)水(shui)(shui)(shui)和(he)其他水(shui)(shui)(shui)源的(de)(de)居民(min)為混合(he)水(shui)(shui)(shui)源觀(guan)察組,飲用水(shui)(shui)(shui)庫水(shui)(shui)(shui)和(he)其他水(shui)(shui)(shui)源水(shui)(shui)(shui)的(de)(de)居民(min)為淡(dan)(dan)(dan)水(shui)(shui)(shui)觀(guan)察組,通過(guo)慢(man)性(xing)(xing)病(bing)網(wang)絡(luo)報告和(he)居民(min)健康檔案系(xi)統進行(xing)慢(man)性(xing)(xing)病(bing)發病(bing)現(xian)狀調(diao)查分析(xi),發現(xian)居民(min)長期飲用海水(shui)(shui)(shui)淡(dan)(dan)(dan)化(hua)水(shui)(shui)(shui)與(yu)惡性(xing)(xing)腫瘤(liu)、冠心病(bing)、腦卒(zu)中(zhong)之間(jian)有相(xiang)關性(xing)(xing)。
三是反(fan)滲透(tou)海水(shui)(shui)(shui)淡(dan)(dan)化過程所需阻垢(gou)劑(ji)可(ke)能具有遺傳(chuan)毒(du)(du)性(xing)(xing)。2018年(nian)中(zhong)國疾(ji)病(bing)預防控制(zhi)中(zhong)心曾用(yong)(yong)體外彗星試驗和(he)流式細胞術(shu)體外微核試驗,檢測不同海水(shui)(shui)(shui)淡(dan)(dan)化阻垢(gou)劑(ji)對(dui)中(zhong)國倉(cang)鼠(shu)卵巢細胞的(de)遺傳(chuan)毒(du)(du)性(xing)(xing)效應,發現(xian)改性(xing)(xing)聚羧(suo)酸阻垢(gou)劑(ji)、聚丙烯酸阻垢(gou)劑(ji)和(he)馬來(lai)酸阻垢(gou)劑(ji)均具有遺傳(chuan)毒(du)(du)性(xing)(xing)。但與(yu)此相(xiang)反(fan),舟(zhou)山(shan)市疾(ji)病(bing)預防控制(zhi)中(zhong)心于(yu)2011年(nian)12月(yue)至2012年(nian)9月(yue)采集嵊泗縣菜園鎮海水(shui)(shui)(shui)原水(shui)(shui)(shui)、海水(shui)(shui)(shui)淡(dan)(dan)化廠(chang)各(ge)(ge)工藝的(de)出水(shui)(shui)(shui)18份,地(di)表水(shui)(shui)(shui)原水(shui)(shui)(shui)和(he)各(ge)(ge)工藝的(de)出水(shui)(shui)(shui)5份,按照ISO—13829推薦的(de)國際(ji)標準(zhun)方法進行(xing)遺傳(chuan)毒(du)(du)性(xing)(xing)試驗,結果表明海水(shui)(shui)(shui)淡(dan)(dan)化飲用(yong)(yong)水(shui)(shui)(shui)的(de)遺傳(chuan)毒(du)(du)性(xing)(xing)明顯低于(yu)以地(di)表水(shui)(shui)(shui)為水(shui)(shui)(shui)源的(de)飲用(yong)(yong)水(shui)(shui)(shui)。
3.福島核(he)廢(fei)水(shui)(shui)排海(hai),引發對海(hai)水(shui)(shui)淡化水(shui)(shui)潛在風險的擔憂
一(yi)是日(ri)本(ben)并未大(da)規(gui)模直接(jie)飲(yin)用(yong)(yong)海(hai)水(shui)(shui)(shui)(shui)淡(dan)化水(shui)(shui)(shui)(shui)。日(ri)本(ben)《水(shui)(shui)(shui)(shui)道(dao)法》中(zhong)的(de)《飲(yin)用(yong)(yong)水(shui)(shui)(shui)(shui)衛(wei)生標準》沒有設(she)置(zhi)放射性指標。本(ben)島(dao)供(gong)水(shui)(shui)(shui)(shui)一(yi)般是以地(di)表水(shui)(shui)(shui)(shui)和地(di)下水(shui)(shui)(shui)(shui)為(wei)(wei)主,海(hai)水(shui)(shui)(shui)(shui)淡(dan)化水(shui)(shui)(shui)(shui)占比(bi)很小。對距本(ben)島(dao)較近(jin)的(de)離島(dao),大(da)多采用(yong)(yong)敷設(she)海(hai)底輸(shu)水(shui)(shui)(shui)(shui)管道(dao)方式直接(jie)供(gong)水(shui)(shui)(shui)(shui)。而(er)距本(ben)島(dao)較遠的(de)離島(dao)則自(zi)行(xing)采用(yong)(yong)小型海(hai)水(shui)(shui)(shui)(shui)淡(dan)化設(she)備供(gong)水(shui)(shui)(shui)(shui),與常規(gui)水(shui)(shui)(shui)(shui)混合(he)后飲(yin)用(yong)(yong)。日(ri)本(ben)的(de)海(hai)水(shui)(shui)(shui)(shui)淡(dan)化工程僅有少數(shu)作為(wei)(wei)市政公(gong)司設(she)施(shi),94%左右的(de)海(hai)水(shui)(shui)(shui)(shui)淡(dan)化廠都(dou)是用(yong)(yong)于產業化實驗。這一(yi)點(dian)應(ying)當引(yin)起(qi)我國注(zhu)意。
二(er)是(shi)放(fang)(fang)射性(xing)核素(su)無法被(bei)海水(shui)淡化(hua)(hua)過程(cheng)完(wan)全(quan)去(qu)(qu)除(chu),且有富集(ji)風險。2021年(nian)4月(yue)13日,日本政府批準了一(yi)項計劃(hua),預計福島第一(yi)核電(dian)站核污染(ran)水(shui)將在30年(nian)內全(quan)部排入太(tai)平(ping)洋,引發了全(quan)球擔憂。其(qi)排放(fang)(fang)的氚(chuan)、碳14、氙、鍶、銫、碘(dian)等放(fang)(fang)射性(xing)核素(su)難以(yi)被(bei)海水(shui)淡化(hua)(hua)完(wan)全(quan)去(qu)(qu)除(chu),特(te)別是(shi)海水(shui)淡化(hua)(hua)對氚(chuan)沒有去(qu)(qu)除(chu)效(xiao)果。
科學推進海水淡化規模化利(li)用的(de)政策建議
規(gui)模化推進海水(shui)淡化,還需科學(xue)論證,完善標準,開展健康風險評估,加強監測評估和國際合作(zuo)。
1.完(wan)善淡(dan)化(hua)用海水及(ji)海水淡(dan)化(hua)水衛生標準,保障規模化(hua)生產利用
一是(shi)參考(kao)《地表水環境質量標(biao)準(zhun)》(GB 3838—2002),修訂《海(hai)水水質標(biao)準(zhun)》,增加“集(ji)中(zhong)式生(sheng)活(huo)飲用水用海(hai)水補充/特定項目標(biao)準(zhun)限制”。
二是加快制定《海(hai)水淡化水飲用衛生(sheng)(sheng)(sheng)標(biao)(biao)準》。以《生(sheng)(sheng)(sheng)活(huo)飲用水衛生(sheng)(sheng)(sheng)標(biao)(biao)準》為指導,根據海(hai)水本身(shen)及其淡化工藝流程的(de)(de)特(te)點選擇適宜的(de)(de)衛生(sheng)(sheng)(sheng)學指標(biao)(biao),如海(hai)水淡化預(yu)處理過(guo)程應納入相應微生(sheng)(sheng)(sheng)物指標(biao)(biao)及一般化學指標(biao)(biao);對海(hai)水淡化中不能完全去除的(de)(de)和(he)新生(sheng)(sheng)(sheng)成的(de)(de)對人(ren)體健康有(you)害的(de)(de)各(ge)種(zhong)物質,人(ren)體必需的(de)(de)鈣、鎂、鐵、鋅、硒(xi)等(deng)營養物質,以及消毒(du)副產(chan)物、管道溶出(chu)物等(deng)設置(zhi)合理的(de)(de)限值或范圍;對海(hai)水淡化水設置(zhi)必需的(de)(de)感官性狀(zhuang)指標(biao)(biao)、放射(she)性指標(biao)(biao)和(he)毒(du)理學指標(biao)(biao)要(yao)求。
2.將海水(shui)淡化水(shui)主要作為備用水(shui)源納入水(shui)資源統一管(guan)理
一是將海水(shui)(shui)淡(dan)化(hua)水(shui)(shui)納(na)入(ru)(ru)水(shui)(shui)資(zi)源統(tong)一管理。建議(yi)修(xiu)改水(shui)(shui)法,將海水(shui)(shui)淡(dan)化(hua)水(shui)(shui)等非常規水(shui)(shui)源納(na)入(ru)(ru)水(shui)(shui)資(zi)源并(bing)享受相關政策;對于沿海地區和海島,明確(que)海水(shui)(shui)淡(dan)化(hua)水(shui)(shui)的戰略備用水(shui)(shui)源地位,將其(qi)納(na)入(ru)(ru)水(shui)(shui)資(zi)源統(tong)一配置(zhi)體系(xi)。
二是將海(hai)水(shui)(shui)(shui)(shui)(shui)淡(dan)化水(shui)(shui)(shui)(shui)(shui)主(zhu)(zhu)要(yao)(yao)作為生活(huo)水(shui)(shui)(shui)(shui)(shui)備用水(shui)(shui)(shui)(shui)(shui)源。截至2019年(nian)年(nian)底,我國海(hai)水(shui)(shui)(shui)(shui)(shui)淡(dan)化水(shui)(shui)(shui)(shui)(shui)主(zhu)(zhu)要(yao)(yao)用途(tu)中,工業用水(shui)(shui)(shui)(shui)(shui)占(zhan)66.6%,生活(huo)用水(shui)(shui)(shui)(shui)(shui)占(zhan)33.1%。在(zai)現(xian)有沿(yan)海(hai)城市水(shui)(shui)(shui)(shui)(shui)資(zi)源配置(zhi)規劃中,海(hai)水(shui)(shui)(shui)(shui)(shui)淡(dan)化水(shui)(shui)(shui)(shui)(shui)應(ying)僅作為戰(zhan)略備用水(shui)(shui)(shui)(shui)(shui)源或補(bu)充水(shui)(shui)(shui)(shui)(shui)源。但在(zai)海(hai)島和(he)船舶等特(te)殊場所,可短期(qi)作為主(zhu)(zhu)要(yao)(yao)飲用水(shui)(shui)(shui)(shui)(shui)源。
三是充(chong)分(fen)(fen)論證(zheng),穩妥(tuo)推(tui)進。從已(yi)建項(xiang)(xiang)目來(lai)看(kan),海(hai)水(shui)(shui)(shui)淡(dan)化項(xiang)(xiang)目利(li)用(yong)(yong)率(lv)普遍較低,單(dan)位(wei)產(chan)水(shui)(shui)(shui)的(de)(de)能源消耗、運營(ying)成本(ben)較高(gao)。建議在項(xiang)(xiang)目建設前充(chong)分(fen)(fen)論證(zheng)項(xiang)(xiang)目用(yong)(yong)水(shui)(shui)(shui)需求、政(zheng)策(ce)條(tiao)件(jian)和建設條(tiao)件(jian),爭取先行(xing)簽訂供水(shui)(shui)(shui)意向協議,保障項(xiang)(xiang)目利(li)用(yong)(yong)率(lv);統籌(chou)規劃淡(dan)化水(shui)(shui)(shui)與傳統自來(lai)水(shui)(shui)(shui)的(de)(de)混合(he)飲用(yong)(yong)。加強(qiang)反滲透工藝,進一步(bu)去除(chu)硼等有害元素,盡量減少阻垢(gou)劑的(de)(de)殘(can)留;海(hai)水(shui)(shui)(shui)淡(dan)化水(shui)(shui)(shui)調質(zhi)工藝采用(yong)(yong)食品級碳酸鈣時,應增強(qiang)水(shui)(shui)(shui)質(zhi)的(de)(de)穩定性(xing)。
3.加強海水及海水淡化水衛生監(jian)測與研究,開展風(feng)險評估(gu)
一是(shi)加強(qiang)海水(shui)(shui)淡(dan)化(hua)(hua)水(shui)(shui)水(shui)(shui)質監測和(he)流行(xing)(xing)病學研(yan)究。鑒于(yu)生活(huo)飲用(yong)水(shui)(shui)衛(wei)生標準對于(yu)淡(dan)化(hua)(hua)水(shui)(shui)的(de)適用(yong)性還需進一步評估,應建立長期(qi)海水(shui)(shui)淡(dan)化(hua)(hua)水(shui)(shui)水(shui)(shui)質監測系統,對產品水(shui)(shui)和(he)管道(dao)末梢(shao)水(shui)(shui)中硼(peng)、消毒副產物、重金屬等進行(xing)(xing)監測,繼續加強(qiang)相(xiang)關(guan)流行(xing)(xing)病學研(yan)究,深入開展(zhan)人群(qun)健(jian)康與飲用(yong)海水(shui)(shui)淡(dan)化(hua)(hua)水(shui)(shui)關(guan)系的(de)調(diao)查。
二是建(jian)立(li)(li)健(jian)康風(feng)險等(deng)級標(biao)準(zhun)。對(dui)于海水(shui)(shui)淡化水(shui)(shui)礦物質不(bu)足(zu)、硬度低(di)、氟含量過低(di)等(deng)帶來的(de)人體(ti)健(jian)康風(feng)險,可參考國內外飲用水(shui)(shui)中鈣、鎂、氟等(deng)的(de)適宜(yi)濃度,建(jian)立(li)(li)風(feng)險等(deng)級標(biao)準(zhun),再將監(jian)測結果(guo)與標(biao)準(zhun)比對(dui),定性分析海水(shui)(shui)淡化水(shui)(shui)對(dui)人體(ti)健(jian)康的(de)風(feng)險。
三(san)是開(kai)展水(shui)質風(feng)險(xian)程度評價(jia)。海水(shui)淡化水(shui)供水(shui)全(quan)過程為海水(shui)淡化水(shui)—后(hou)處理—管網—用戶,對全(quan)過程的(de)風(feng)險(xian)評估可參(can)考食(shi)品生產的(de)危害分析(xi)與關鍵(jian)控制點(HACCP)體系,對海水(shui)淡化水(shui)的(de)水(shui)質風(feng)險(xian)程度進行評價(jia)分析(xi)。
四是(shi)開展海洋放(fang)射性監測評估和國(guo)(guo)際合作。未來(lai)30年(nian)甚至更長(chang)時期(qi),建(jian)議與相關國(guo)(guo)際機構和國(guo)(guo)家建(jian)立長(chang)期(qi)合作研究交(jiao)流機制(zhi),監測區域(yu)不僅要涵蓋(gai)日本沿(yan)海區域(yu)特別(bie)是(shi)福島海域(yu),還應涵蓋(gai)北(bei)太(tai)平(ping)洋海域(yu)及邊緣海海域(yu),以開展全面的海洋放(fang)射性及海水(shui)水(shui)質衛生(sheng)預(yu)測—監測—評估工作,及早發現(xian)風(feng)險(xian),確(que)保我(wo)國(guo)(guo)海水(shui)淡化水(shui)的衛生(sheng)安(an)全性。

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