本文關(guān)鍵詞： 南淝河 沉積物 營養(yǎng)物 釋放 原位控制　出處：《合肥工業(yè)大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：南淝河沉積物記錄著水體污染歷史、人類影響和環(huán)境變遷,沉積物與水體有著緊密的相互作用,研究南淝河沉積物的污染現(xiàn)狀及其動態(tài)變化,對控制南淝河水體內(nèi)源負(fù)荷和生態(tài)系統(tǒng)狀況有著重要的理論和實際意義。本研究在國家水體污染控制與治理科技重大專項(2011ZX07303-002)的依托下,通過室內(nèi)實驗分析,對南淝河疏浚工程示范段沉積物中營養(yǎng)物和重金屬的污染特征、環(huán)境風(fēng)險的評價,沉積物—上覆水界面營養(yǎng)物的釋放規(guī)律,以及原位控制技術(shù)對南淝河沉積物營養(yǎng)物釋放的影響效果進(jìn)行了系統(tǒng)的研究,主要研究成果如下：(1)南淝河疏浚工程示范段十個代表性采樣點沉積物檢測結(jié)果表明：沉積物中氮、磷、有機(jī)質(zhì)的含量范圍分別為253.83mg/kg-1235.73mg/kg、 131.34mg/kg-1068.75mg/kg和1.49%-6.83%,其中表層沉積物中氮磷的含量較高。根據(jù)有機(jī)氮和有機(jī)指數(shù)評價結(jié)果發(fā)現(xiàn),示范段存在一定程度的氮污染和有機(jī)污染。示范段表層沉積物中重金屬P、 Zn、 Cr的含量范圍為21.6-152.9mg/kg、 36.7-1529mg/kg和33.6-132.6mg/kg。根據(jù)地累積指數(shù)法和潛在生態(tài)危害系數(shù)法評價結(jié)果發(fā)現(xiàn),沉積物重金屬元素污染程度排序為Zn Pb Cr;各采樣點的Zn含量都已超過安全值,其中P8、P9、P10采樣點的Zn污染較為嚴(yán)重；Pb污染主要集中在下游地區(qū)；Cr污染程度較輕,主要分布在P9和P10采樣點。(2)沉積物—上覆水界面營養(yǎng)物釋放規(guī)律試驗結(jié)果表明：a.水體的環(huán)境溫度越高,對沉積物—上覆水界面營養(yǎng)物的釋放影響就越大。溫度由5℃升至25℃時,上覆水總磷濃度呈現(xiàn)先升高后緩慢下降的趨勢,總氮濃度由慢到快的增長,COD濃度增加了1.64倍；b.水體的環(huán)境pH值為7時,沉積物—上覆水界面氮磷和COD釋放量最小,降低或升高pH值均使沉積物營養(yǎng)物的釋放量增加；C.擾動對沉積物—上覆水界面營養(yǎng)物的釋放影響較大,當(dāng)有足夠的擾動強(qiáng)度時,沉積物會發(fā)生再懸浮,導(dǎo)致上覆水氮磷和COD濃度的升高。(3)投加某物化凝聚劑原位控制沉積物營養(yǎng)物釋放的影響效果試驗結(jié)果表明：凝聚劑的投加量為800mg/L(“L”為沉積物體積)時,對沉積物營養(yǎng)物釋放的控制效果最好。
[Abstract]:The sediment of Nanfeihe River records the history of water pollution, human influence and environmental change, and there is a close interaction between sediment and water body. The present situation and dynamic change of sediment pollution in Nanfeihe River are studied. It is of great theoretical and practical significance to control the internal load of water body and the condition of ecosystem in Nanfeihe River. This study is based on the important scientific and technological project of water pollution control and treatment in China (2011ZX07303-002). The pollution characteristics of nutrients and heavy metals in sediment, environmental risk assessment and nutrient release from sediment to overlying water interface in the demonstration section of dredging project of Nanfeihe River were studied. And the effect of in-situ control technology on nutrient release from sediment of Nanfeihe River was systematically studied. The main results are as follows: 1) the results of sediment detection at ten representative sampling sites in the dredging project of Nanfeihe River show that: nitrogen in sediment, The contents of phosphorus and organic matter were 253.83 mg / kg 1235.73 mg / kg, 131.34 mg / kg 1068.75 mg / kg and 1.49 ~ 6.83 mg / kg, respectively. The contents of heavy metals P, Zn, Cr in the surface sediments of the demonstration section were 21.6-152.9 mg / kg, 36.7-1529 mg / kg and 33.6-132.6 mg / kg respectively. The pollution degree of heavy metal elements in sediments is in the order of Zn Pb Cr.The Zn content in each sampling site has exceeded the safe value, among which Zn pollution in P8 P9 P10 sampling site is more serious and Pb pollution is mainly concentrated in the lower reaches of the area. The results showed that the higher the ambient temperature of the water was, the higher the environmental temperature was, the higher the environment temperature was, the higher the nutrient release rate was at the interface between sediment and overlying water, which was mainly distributed in the sampling sites of P9 and P10. When the temperature increased from 5 鈩，

本文編號：1528166