中文摘要：

大沽河是胶州湾周边径流量最大的入海河流,明确其入海口污染物浓度的变化特征对胶州湾实施陆源污染控制具有重要的意义。本文利用2001—2013年的月监测数据和2013年的日监测数据,分析了大沽河入海口CODcr和NH4-N浓度的年际、月际和日变化特征及其影响因素。从年际变化看,CODcr和NH4-N的浓度呈下降趋势,自2004年始达到了水功能区标准要求;2001—2007年的污染物浓度下降主要源于点源污染治理,2008年始非点源污染上升为主要污染源,污染物浓度没有明显下降。从月际变化看,受降雨径流的冲刷、稀释以及农田肥料流失的影响,CODcr和NH_4-N的浓度随降雨量增大而增大。从不同水期日均值的变化看,CODcr和NH_4-N浓度也与降雨量有关,其日均浓度呈现丰水期高、平水期和枯水期低的变化特征。

英文摘要：

To find out multi-time scale variations of pollutants in the estury of Dagu River, the annual, monthly, and daily concentration of pollutants was studied and associated with precipitation and runoff based on the annual data from 2001 to 2013 and daily data in 2013. The annual concentration of CODer and NH4-N was 20-40 and 0.2-4.2 mg/L from 2001 to 2013, and both showed a decreasing trend, especial- ly from 2001 to 2004. Since 2004, the concentration of CODcr and NH4-N decreaseed to 20-30 mg/L and 〈1 mg/L, which reached the water quality standard of the function zone. The concentration of pollutants decreased from 2001 to 2007 owing to the treatment of point source pollution. The concentration of pollutants has not decrease since 2008 due to the non-point pollution being the main source of pollution. According to the monthly and daily concentration of pollutants in 2013, the monthly concentration of CODer and NH4-N was 18-26 and 0. 1-0.3 mg/L reaching the water quality standards of Class Ⅳ and Ⅱ. The water pollution was more serious during the wet season and related to the non-point pollution from strong precipitation. The high concentration of CODer and NH4-N corresponds to the high precipitation. The concentration of CODer was effected by washing and dilution from precipitation and runoff. As for NH4- N, except for these two factors, its concentration was also influenced by non-point pollution from agricul- tural planting and fertilization. The study showed the characteristics of multi-time scale variation and its various factor, and supplies basic research materials for the treatment of water pollution in Dagu River es- tuary and Jiaozhou Bay.