生态环境学报
生態環境學報
생태배경학보
ECOLOGY AND ENVIRONMENT
2014年
2期
277-282
,共6页
富营养化%沉积物%重金属%形态%相关性
富營養化%沉積物%重金屬%形態%相關性
부영양화%침적물%중금속%형태%상관성
eutrophication%sediment%heavy metals%fractionation%correlation
对太湖、南四湖、白洋淀三个不同富营养化湖泊沉积物进行采样,采用Tessier连续提取法,测定了3个湖泊表层沉积物中Cu、Zn两种重金属的赋存形态,并初步探讨了重金属各形态与沉积物及上覆水中营养盐的相关关系。结果表明,沉积物中重金属总量以白洋淀最高,太湖最低,但重金属污染程度为太湖>南四湖>白洋淀,太湖Cu污染指数为1.34~1.6,白洋淀Cu污染指数仅为0.79~1.17。沉积物中重金属赋存形态Cu主要以残渣态和有机质结合态为主(二者之和占73%以上), Zn则以残渣态和Fe-Mn氧化态占优(二者之和比例达83%以上),含量最少的均为可交换态。不同湖泊沉积物重金属赋存形态差异较大,太湖残渣态重金属占总量的比例最小(Cu为43%~56%,Zn为49%~63%),南四湖残渣态占的比例最大(Cu为59%~82%、Zn为64%~77%);可交换态比重在太湖中最高(Cu占3.2%~5.6%,Zn为1.3%~1.5%),在南四湖中最低(Cu为1.1%~2.9%,Zn未检出)。从“非稳定态”重金属(除残渣态外的四种形态之和)所占比例看,相较其它两个湖泊,太湖沉积物中重金属污染人为输入的活性态占较大比重,具有较高的二次释放风险。相关性分析得出,重金属Cu的可交换态与上覆水中总氮及总磷之间存在着极显著的正相关关系,碳酸盐结合态Cu与沉积物中营养盐呈现出显著的负相关性,说明水体的富营养化程度加剧可能会增强沉积物中Cu向水体释放的风险。
對太湖、南四湖、白洋澱三箇不同富營養化湖泊沉積物進行採樣,採用Tessier連續提取法,測定瞭3箇湖泊錶層沉積物中Cu、Zn兩種重金屬的賦存形態,併初步探討瞭重金屬各形態與沉積物及上覆水中營養鹽的相關關繫。結果錶明,沉積物中重金屬總量以白洋澱最高,太湖最低,但重金屬汙染程度為太湖>南四湖>白洋澱,太湖Cu汙染指數為1.34~1.6,白洋澱Cu汙染指數僅為0.79~1.17。沉積物中重金屬賦存形態Cu主要以殘渣態和有機質結閤態為主(二者之和佔73%以上), Zn則以殘渣態和Fe-Mn氧化態佔優(二者之和比例達83%以上),含量最少的均為可交換態。不同湖泊沉積物重金屬賦存形態差異較大,太湖殘渣態重金屬佔總量的比例最小(Cu為43%~56%,Zn為49%~63%),南四湖殘渣態佔的比例最大(Cu為59%~82%、Zn為64%~77%);可交換態比重在太湖中最高(Cu佔3.2%~5.6%,Zn為1.3%~1.5%),在南四湖中最低(Cu為1.1%~2.9%,Zn未檢齣)。從“非穩定態”重金屬(除殘渣態外的四種形態之和)所佔比例看,相較其它兩箇湖泊,太湖沉積物中重金屬汙染人為輸入的活性態佔較大比重,具有較高的二次釋放風險。相關性分析得齣,重金屬Cu的可交換態與上覆水中總氮及總燐之間存在著極顯著的正相關關繫,碳痠鹽結閤態Cu與沉積物中營養鹽呈現齣顯著的負相關性,說明水體的富營養化程度加劇可能會增彊沉積物中Cu嚮水體釋放的風險。
대태호、남사호、백양정삼개불동부영양화호박침적물진행채양,채용Tessier련속제취법,측정료3개호박표층침적물중Cu、Zn량충중금속적부존형태,병초보탐토료중금속각형태여침적물급상복수중영양염적상관관계。결과표명,침적물중중금속총량이백양정최고,태호최저,단중금속오염정도위태호>남사호>백양정,태호Cu오염지수위1.34~1.6,백양정Cu오염지수부위0.79~1.17。침적물중중금속부존형태Cu주요이잔사태화유궤질결합태위주(이자지화점73%이상), Zn칙이잔사태화Fe-Mn양화태점우(이자지화비례체83%이상),함량최소적균위가교환태。불동호박침적물중금속부존형태차이교대,태호잔사태중금속점총량적비례최소(Cu위43%~56%,Zn위49%~63%),남사호잔사태점적비례최대(Cu위59%~82%、Zn위64%~77%);가교환태비중재태호중최고(Cu점3.2%~5.6%,Zn위1.3%~1.5%),재남사호중최저(Cu위1.1%~2.9%,Zn미검출)。종“비은정태”중금속(제잔사태외적사충형태지화)소점비례간,상교기타량개호박,태호침적물중중금속오염인위수입적활성태점교대비중,구유교고적이차석방풍험。상관성분석득출,중금속Cu적가교환태여상복수중총담급총린지간존재착겁현저적정상관관계,탄산염결합태Cu여침적물중영양염정현출현저적부상관성,설명수체적부영양화정도가극가능회증강침적물중Cu향수체석방적풍험。
The chemical speciation of heavy metal Cu and Zn in the surface sediments of Tai Lake, Nansi Lake and Baiyangdian Lake was measured by Tessier sequential extraction methods. The relationship between heavy metal fractions and nutrients in sediments and overlying water was also discussed. Experimental results showed that the highest total contents of heavy metals occurred in Baiyangdian Lake and the lowest occurred in Tai Lake. The order of severities of heavy metal pollution were Tai Lake>Nansi Lake>Baiyangdian Lake. Pollution index for Cu was 1.34~1.6 in Tai Lake, and was 0.79~1.17 in Baiyangdian Lake. In sediments, Cu existed mainly in the form of residual and organic-bound fractions, accounting for more than 73%of the total content. The dominated fractions of Zn were the residual fraction and the Fe/Mn oxide fraction, accounting for more than 83%of the total content. The exchangeable fraction was the lowest for both Cu and Zn. The occurrence characteristics of heavy metals from different lake sediments have diversity. For the three lakes, the proportion of residual fraction in the Tai Lake was the lowest, with the percentage of residual Cu was 43~56%and the percentage of residual Zn was 49~63%. The proportion of residual fraction was the highest in the Nansi Lake, with the proportion of residual Cu and Zn were 59~82% and 64~77% respectively. The proportion of exchangeable fraction was the highest in the Tai Lake, with the proportion of exchangeable Cu was 3.2~5.6%and the proportion of exchangeable Zn was 1.3~1.5%. The proportion of exchangeable fraction was the lowest in the Nansi Lake, with the proportion of exchangeable Cu was 1.1~2.9%, and exchangeable Zn was undetected. This studies also showed the total“labile”fraction (the sum of four forms of heavy metal except residual fraction) extracted from heavy metals was the highest in Tai Lake, which might bring more serious ecological risk to the water ecological system, and should be paid more attention to. According to correlation analysis, the exchangeable fraction of Cu was significantly correlated to TP and TN in overlying water, and there was a negative correlation between the carbonate-bound Cu and nutrients in sediments, indicating that eutrophic level of water might have an important influence on the release of Cu. The aggravation of eutrophication might enhance the risk of Cu release from the sediments to water.