沉积时间和温度对底泥间隙水有机污染物的影响

Effect of Formation Time and Environ mental Temperature on Organic Contaminant in Pore Water of Bottom Sediment

通过底泥培养试验,研究了沉积时间和温度对底泥间隙水相有机污染物的影响。结果表明,环境温度对于底泥间隙水中有机污染物浓度影响很大,一是体现在污染物浓度增加的速率,二是体现在平衡浓度的大小。较高的环境温度对应更高的间隙水相污染物浓度。从沉积开始,底泥系统的pH呈逐渐下降的趋势,在起始的2d中下降显著,而后逐渐达到平衡;环境温度的影响明显,较低的温度对应较高的pH值。底泥Eh也呈逐渐下降,但主要下降段集中在起始的24h以内,在大约48h后基本达到平衡状态;环境温度对底泥系统的Eh变化影响很大,但对底泥系统的氧化还原电位测量影响小。针对底泥间隙水有机污染物的特点,首次提出原始底泥的概念,这将有利于考虑污染底泥的水质模型的建立。

Scour,deposition and re-suspension of bott om sediment are key factors that dominate the action of endogeni c contami-nants in natural water system,and as a result of those processes,releasing of contam inants in pore water acts as a main polluting approach.By culturing experiment of bottom sediment,the effect of form ation time and environmental temperature on organic con-taminant in pore water of bottom sedi ment was studied.The resu lts show th at,the environmental temperature i nfluences the con-centration of organic contaminant i n pore water significantly,especia lly on the creating r ate and equilibr iumcontent of organic matter in pore water,and the organic con cen tration is increasing greatly with r ising temperature.Since formation of b ottomsediment,the pH value is dropping,which is distinct in about first two da ys,and is rising following the decline of temperatur e.The action of Eh is sam e as that of pH,besides the dropping period is in the first day mainly and the equilibrium time is less than 48hrs.Temperature dom-inates the variation of Eh effective ly,but on measurement of sediment slightly.Finally,in accordanc e with the characteristics of organic contaminant in pore water of bottom sedime nt system,a new concep t,original bottom sediment,was pro posed,which refers to contaminated sediment having ach ieved equilibrium of contaminant di stribut ion in it.And to given contam inated sediment,the amount of releasable contami nant is easy to determined,which is in favor of building of water quality model wi th the consideration of contaminated bottom sediment.