汞对微生物的毒性效应研究

STUDY ON TOXICITY OF MERCURY TO MICROBE

本文用细菌生物曲线测定法和刃天青还原抑制试验研究了汞（Ｈｇ＋２）对混合细菌生长速度（ＧＲ）及总脱氢酶活性（ＴＤＨＡ）的影响。结果表明，Ｈｇ＋２浓度在一定范围内，细菌ＧＲ和ＴＤＨＡ抑制率随其浓度的增加而增加。在不同终点观察时间，Ｈｇ＋２对细菌ＧＲ的半数抑制浓度（ＩＣ５０）值明显不同，其中以４ｈＩＣ５０值（０．２９２ｍｇ／Ｌ）最小；并观察到，细菌相对生长量（ＲＧＹ）在培养一定时间后存在回升规律，即ＲＧＹ回升的起点时间随Ｈｇ＋２浓度的增加而推迟，Ｈｇ＋２对细菌ＴＤＨＡ的ＩＣ５０和抑制阈浓度（ＩＴＣ）分别为０．８２５、０．３３０ｍｇ／Ｌ。汞对细菌ＧＲ的影响比对ＴＤＨＡ敏感。

The toxicity of mercury(Hg+2)on growth rate(GR)and total dehydrogenase activity(TDHA)of mixed bacterial culture was studied using measurement method of growth curve and resazurin reduction test.The results showed that the inhibition of GR and TDHA by Hg+2 increased with its concentration in cerain range.After various culture time the 50% inhibition concentration(IC50)of Hg+2 on GR of bacteria was different obviously,IC50 for 4 hours was the lowest(0.292mg/L). We observed that the staring time of reviving of bacterial relative growth yield(RGY)would be postponed with the increase of the concentration of Hg+2.IC50 and inhibiting threshold concentration(ITC)of Hg+2 on TDHA was 0.825、0.330mg/L respectively.The toxic effect of mercury on GR of mixed bacteria is more sensitive than on TDHA.