小清河口春季亚硝酸盐偏高问题探讨

Discussion on the High Nitrite Phenomenon in the Xiaoqing River Estuary in Spring

2008年春季对莱州湾小清河口的走航调查发现，调查区域大部分水体的DOC，CODMn，NH4^＋ -N，POi4^3- -P高于4类海水的限定值，处于严重污染状态。水体CHla的浓度范围在1．02-37．92μg／L之间，但DO饱和度却在23％～96％之间，盐度小于15水体的DO饱和度低于50％，水体缺氧严重。河口存在NO2^- -N含量偏高现象。由河口向外，NO2^- -N浓度逐渐增加，至盐度24．4的水体达到0．27mg／L的高值，NO2^- -N增加主要是NH4^＋ -N的硝化反应产生的。NH4^＋-N生成NO2^-N主要受DO和NH4^＋-N比例与浓度的影响，DO饱和度在30％～70％，NH4^＋ -N大于3．33mg／L的水体中NO2^--N生成速率最快。

We investigated dissolved oxygen, some nutrients and other associated parameters in the Xiao- qing River estuary, a highly polluted estuary during the spring of 2008. The large area of the estuary was anoxic, with unconventionally high level of carbon, nitrogen and phosphorus concentrations. Additionally, the values of chemical oxygen demand, ammonia and phosphate were high above that of the IV seawater quality, according to the national standards of seawater quality. High nitrite value was detected in the estuary, mainly resulted from nitrification. Since the nitrification that ammonia oxidated to nitrite was controlled by dissolved oxygen and ammonia concentration, the increasing rate of nitrite was surveyed while dissovled oxygen between 30-70% and ammonia concentration upon 3.33 mg/l.