國(guo)內的(de)(de)桶(tong)裝(zhuang)水(shui)(shui)起(qi)步較晚,所(suo)以都是(shi)(shi)沿用國(guo)外(wai)的(de)(de)生產線和標準,國(guo)外(wai)的(de)(de)都是(shi)(shi)采用加(jia)侖(lun)為(wei)單位:1桶(tong)水(shui)(shui)=19升(sheng)(sheng)=5加(jia)侖(lun)水(shui)(shui),1加(jia)侖(lun)水(shui)(shui)=3.75升(sheng)(sheng),較早(zao)時桶(tong)裝(zhuang)水(shui)(shui)容(rong)量(liang)分為(wei)3加(jia)侖(lun)(≈11.34升(sheng)(sheng))和5加(jia)侖(lun)(≈18.9升(sheng)(sheng))兩種規格。而目前國(guo)內市場桶(tong)裝(zhuang)水(shui)(shui)幾乎都是(shi)(shi)5加(jia)侖(lun)裝(zhuang),也就是(shi)(shi)我(wo)們常見的(de)(de)18.9升(sheng)(sheng)桶(tong)裝(zhuang)水(shui)(shui)。
桶裝水(shui)(shui)未(wei)未(wei)開封(feng)時,保(bao)質(zhi)期有(you)3個月。若已開封(feng)的(de)(de)桶裝水(shui)(shui),理論(lun)上保(bao)質(zhi)期有(you)15天,但建議(yi)最好在(zai)5-7天內引用完,儲存(cun)時間過長,很容(rong)易造成細菌滋生、水(shui)(shui)質(zhi)污染。這是因為飲水(shui)(shui)機里的(de)(de)水(shui)(shui)、空(kong)氣、合(he)適的(de)(de)溫度(du)給大腸桿菌、厭氧菌、綠膿桿菌、霉菌等細菌繁殖提供了合(he)適的(de)(de)條(tiao)件,時間一長,就(jiu)會嚴重影響到(dao)飲用水(shui)(shui)的(de)(de)質(zhi)量。
礦(kuang)物質水就(jiu)用(yong)(yong)(yong)PC桶(tong)(tong)(tong)(是好桶(tong)(tong)(tong):只是相(xiang)對來說,不(bu)過用(yong)(yong)(yong)久(jiu)了也(ye)會越來越產生(sheng)化(hua)學物質:雙酚A),這種(zhong)桶(tong)(tong)(tong)透(tou)明(ming)度好、剛性高,所以桶(tong)(tong)(tong)壁(bi)不(bu)很厚,而且是無色透(tou)明(ming)的(de)(de), TPE桶(tong)(tong)(tong)(一(yi)般瓶(ping)裝(zhuang)水一(yi)次性用(yong)(yong)(yong)的(de)(de),反復(fu)使(shi)用(yong)(yong)(yong)有毒,好多(duo)地方明(ming)令(ling)不(bu)得使(shi)用(yong)(yong)(yong))2004年,國家明(ming)令(ling)禁止PET桶(tong)(tong)(tong)循環用(yong)(yong)(yong)于(yu)桶(tong)(tong)(tong)裝(zhuang)水包裝(zhuang)。雖然現在要(yao)求對水桶(tong)(tong)(tong)也(ye)要(yao)進行QS認證,但是一(yi)些(xie)企業(ye)送(song)檢(jian)的(de)(de)桶(tong)(tong)(tong)是合格的(de)(de),而真正使(shi)用(yong)(yong)(yong)的(de)(de)則可能不(bu)合格。
許(xu)多(duo)城鎮居民家中都用(yong)上了(le)桶(tong)裝純凈水,并(bing)成了(le)家庭飲水的主要方式(shi)。有關(guan)部(bu)門曾檢測過開封(feng)飲用(yong)兩周的桶(tong)裝水,結果(guo)其細菌(jun)總數都超過了(le)桶(tong)裝水出廠標準(zhun)上限的12.5倍。
桶(tong)(tong)裝(zhuang)水(shui)普遍存在(zai)著的“二次(ci)污染(ran)(ran)”是(shi)無法避免的。送水(shui)無一例外都是(shi)雇自(zi)行車、三輪車送,整個(ge)送水(shui)過程中由于受到時間、氣候(hou)、環境(jing)、人員素質的影響(xiang),“二次(ci)污染(ran)(ran)”可能性極(ji)(ji)大(da)。飲(yin)水(shui)機(ji)在(zai)出水(shui)的同時,空氣中的病菌(jun)、塵(chen)埃(ai)會不可避免地進入飲(yin)水(shui)機(ji)和水(shui)桶(tong)(tong)中,細菌(jun)的大(da)量生存繁殖,對人們(men)的身體(ti)健(jian)康極(ji)(ji)為不利。桶(tong)(tong)裝(zhuang)水(shui)還普遍存在(zai)“千(qian)滾水(shui)”問題,桶(tong)(tong)裝(zhuang)水(shui)在(zai)飲(yin)水(shui)機(ji)內被反復加熱(re),會形成“千(qian)滾水(shui)”,看似干凈,其實(shi)卻是(shi)重金(jin)屬、砷化物等有害物質的濃縮(suo)液。
按照規定,每只(zhi)水(shui)(shui)桶(tong)在(zai)反復使用(yong)(yong)100次后,就(jiu)要報廢(fei)。專家說,報廢(fei)桶(tong)往往是細菌滋(zi)生的(de)(de)“樂(le)土”。一些(xie)中(zhong)小(xiao)桶(tong)裝(zhuang)水(shui)(shui)廠家對(dui)回(hui)收的(de)(de)空桶(tong)并不進(jin)行認(ren)真(zhen)消(xiao)毒(du),只(zhi)在(zai)自來水(shui)(shui)里(li)簡(jian)單(dan)地沖(chong)刷一下就(jiu)使用(yong)(yong),導致水(shui)(shui)桶(tong)中(zhong)的(de)(de)細菌大(da)量繁(fan)殖(zhi),用(yong)(yong)這(zhe)種(zhong)桶(tong)裝(zhuang)水(shui)(shui),再好的(de)(de)水(shui)(shui)也肯定被(bei)污染了(le)。“黑(hei)桶(tong)”并沒有(you)完全退出市(shi)場(chang),水(shui)(shui)桶(tong)超時服役(yi)現象嚴(yan)重,本(ben)該淘汰的(de)(de)廢(fei)舊(jiu)桶(tong)仍在(zai)大(da)量使用(yong)(yong),這(zhe)對(dui)桶(tong)裝(zhuang)水(shui)(shui)造成很大(da)的(de)(de)污染。
“黑(hei)心水(shui)(shui)(shui)”是(shi)(shi)指(zhi)不(bu)法商販用自來水(shui)(shui)(shui)直接灌裝(zhuang)成(cheng)的(de)桶(tong)裝(zhuang)水(shui)(shui)(shui),“黑(hei)心桶(tong)”的(de)工業廢料(liao)里(li)的(de)高(gao)分子聚合(he)物(wu),在水(shui)(shui)(shui)體環境中會滲出,這是(shi)(shi)一(yi)種有機污染物(wu),容(rong)易使人(ren)體致癌。人(ren)飲用了“黑(hei)心桶(tong)”裝(zhuang)的(de)水(shui)(shui)(shui),不(bu)會立刻有感(gan)覺,而是(shi)(shi)像慢性中毒一(yi)樣,危(wei)害在多年后才會表現出來。
正(zheng)規的(de)(de)桶(tong)(tong)裝(zhuang)水(shui)在(zai)桶(tong)(tong)身或者(zhe)桶(tong)(tong)底會(hui)印有(you)(you)(you)“QS”的(de)(de)標志(zhi)。同時(shi)還會(hui)印有(you)(you)(you)生(sheng)產日(ri)期(qi)和保(bao)質(zhi)期(qi)。在(zai)倒三角的(de)(de)標志(zhi)里會(hui)印有(you)(you)(you)“PC”的(de)(de)字樣,表(biao)明(ming)桶(tong)(tong)的(de)(de)材質(zhi)為(wei)PC料。不同的(de)(de)桶(tong)(tong)裝(zhuang)水(shui)保(bao)質(zhi)期(qi)也不同,有(you)(you)(you)的(de)(de)45天(tian)有(you)(you)(you)的(de)(de)30天(tian)。但原則(ze)上(shang)已開封的(de)(de)桶(tong)(tong)裝(zhuang)水(shui)最好(hao)在(zai)兩(liang)個星期(qi)之(zhi)內喝(he)完,以防(fang)造成(cheng)二次污染。正(zheng)規桶(tong)(tong)裝(zhuang)水(shui)桶(tong)(tong)體透(tou)明(ming)度(du)高,顏(yan)色(se)多(duo)為(wei)藍色(se)或白色(se)。不合格(ge)的(de)(de)水(shui)桶(tong)(tong)透(tou)明(ming)度(du)差,顏(yan)色(se)為(wei)深藍色(se)或紫色(se),有(you)(you)(you)時(shi)還會(hui)有(you)(you)(you)黑點。購買桶(tong)(tong)裝(zhuang)水(shui)的(de)(de)時(shi)候(hou)要注意一下(xia)幾點事項。
有些(xie)家庭可(ke)能(neng)人(ren)數較少或因(yin)為(wei)工(gong)作原(yuan)因(yin)多(duo)不在家,飲水量比較少。這(zhe)樣一來很可(ke)能(neng)18.9L的(de)桶(tong)裝水在15天之內難以喝完。這(zhe)樣的(de)情況(kuang)最好(hao)是能(neng)大換(huan)小(xiao),即換(huan)用3加(jia)侖的(de)桶(tong)裝水。
首先要觀察桶(tong)體,一(yi)般其透(tou)明度高,顏色(se)多為藍色(se)或白色(se)。外(wai)包裝左上方標有QS標志,并(bing)注明了生(sheng)產日(ri)期、保質(zhi)期和衛生(sheng)許可證等(deng)。每桶(tong)純(chun)凈水上都注明保質(zhi)期為45天。正規的桶(tong)裝水封(feng)(feng)口處都會標明生(sheng)產日(ri)期和保質(zhi)期,一(yi)般在(zai)沒開(kai)封(feng)(feng)的情況下,可以保存兩至(zhi)三個(ge)月(yue)(yue)。不過一(yi)經開(kai)封(feng)(feng),最好在(zai)半(ban)個(ge)月(yue)(yue)之內喝完。
盡(jin)量挑(tiao)選新桶、透明無(wu)色(se)桶裝的(de)(de)水。舊桶使用時間長,內壁會(hui)不光滑,特別是(shi)存放礦泉水的(de)(de)桶,內壁容易產(chan)生礦物質沉淀,不容易清(qing)洗干凈,會(hui)滋生細菌。和(he)透明無(wu)色(se)桶相比,淡藍色(se)的(de)(de)桶或者(zhe)淡綠色(se)的(de)(de)桶容易替(ti)水質“遮(zhe)羞”。
檢查桶(tong)(tong)蓋是否密(mi)封(feng)。不妨用手(shou)輕(qing)輕(qing)旋轉(zhuan)桶(tong)(tong)蓋,或者將桶(tong)(tong)身橫向平放地面。桶(tong)(tong)蓋如果能夠轉(zhuan)動,或者桶(tong)(tong)口有水滲出,則說明桶(tong)(tong)蓋不密(mi)封(feng)。
注意(yi)產(chan)品的生產(chan)日(ri)期,盡可(ke)能飲(yin)用近期生產(chan)的產(chan)品。盡量不要選擇保質(zhi)(zhi)期快(kuai)過期的水,通常此時的水質(zhi)(zhi)已不太理想。一般在飲(yin)水機上的桶(tong)裝水,飲(yin)用期一般不超過15天,否(fou)則,水質(zhi)(zhi)容易受(shou)到(dao)空氣中細菌的污(wu)染。
飲水(shui)(shui)(shui)機上通常都有(you)(you)冷熱(re)兩個(ge)水(shui)(shui)(shui)嘴,但(dan)有(you)(you)些人(ren)不(bu)喜歡喝熱(re)水(shui)(shui)(shui),長期冷落熱(re)水(shui)(shui)(shui)嘴。由于兩個(ge)水(shui)(shui)(shui)嘴是分格存水(shui)(shui)(shui),所(suo)以應定(ding)期輪(lun)流排水(shui)(shui)(shui),以免水(shui)(shui)(shui)因久不(bu)流動(dong)而生(sheng)變。注意不(bu)要將桶裝(zhuang)水(shui)(shui)(shui)放在陽(yang)光照射的地方。陽(yang)光照射的桶裝(zhuang)水(shui)(shui)(shui)容易產生(sheng)藻類,滋(zi)生(sheng)細菌,導致菌落總數(shu)超標(biao)。
飲水機的清(qing)洗是水質的保障。