通过研究不同环境条件对镉在内秦淮河逸仙桥处沉积物中的吸附与释放及形态转化规律的影响,发现吸附量和释放量都随温度升高而增大;吸附量随pH值增大而增大、随盐度增大而减小;pH值改变对沉积物中镉形态的影响较小。盐度增大,镉的生物有效性降低。镉释放量随pH值增大而减少、随盐度增大而增大。在不同环境条件下,沉积物中镉达最大释放量时释放的形态不同,pH值为5时,释放镉以碳酸盐结合态为主,由20.67%降至2.1%;盐度为10%时,释放镉以有机结合态为主,由15.24%降至6.32%;温度为30℃时,以可交换态为主,由16.48%减少至1.6%。
The adsorption,release and form transformation of cadmium in sediments at Yixian Bridge across internal Qinhuai River under different environmental conditions were studied.The results showed that,both adsorption quantity and release quantity increased along with the temperature rising,the adsorption quantity increased with the increasing of pH value and decreased with the increasing of salinity;the pH value had a little effect on the form of Cd in the sediments.With the salinity increasing,the biological effectiveness of Cd decreased.The release quantity of Cd decreased with pH value increasing and increased with salinity increasing.Under different environmental conditions,Cd in sediments had different release forms when it reached its biggest release capacity.When pH value was 5,Cd was released mostly in the form of carbonate bound and the mass fraction reduced from 20.67% to 2.1%;when the salinity was 10%,Cd was released mostly in the form of organic bound and the mass fraction reduced from 15.24% to 6.32%;when t was 30 ℃,Cd was released mostly in the form of exchangeable cadmium,and the mass fraction reduced from 16.48% to 1.6%.