摘要目的 为了解东江东莞段水质污染情况并进行原因分析.方法 本课题在东江东莞段及南北干流段共设置了7个采样断面,对比《地表水环境质量标准》(GB3838-2002),从感官性状(透明度、色度、水温、pH值)、化学指标(溶解氧、高锰酸盐指数、生化需氧量、三氮、铬、镉、铅等15种金属离子)、细菌学指标三个方面,共26项,对东江东莞段的水质进行检测分析.结果 水质呈中性,水温变化明显,水色度从上游到下游由清澈透明逐渐变为浑浊；丰水期:溶解氧0.04 ～ 2.26 mg/L,化学需氧量1.49～2.83 mg/L,生化需氧量4.50 ～ 22.00 mg/L,氨氮2.40～29.84 mg/L,硝酸盐氮8.43 ～ 2346mg/L,亚硝酸盐氮0.008～0.449mg/L,六价铬0500～12.714 mg/L;枯水期:溶解氧0.62～2.30mg/L,化学需氧量3.75 ～ 4.86 mg/L,生化需氧量4.40～ 19.00mg/L,氨氮3.98 ～ 27.99 mg1/L,硝酸盐氮0.57～0.99 mg/L,亚硝酸盐氮42.70～83.28 mg/L,六价铬0.336 ～ 8.609 mg/L;7个监测点的14种金属离子(镉、铅、砷、汞、锰、镍、钾、钠、钙、镁、铁、硒、锌、铜)在丰水期和枯水期均未发现有超标现象；总体显示上游属于Ⅰ～Ⅲ类水标准,下游为Ⅳ ～Ⅴ类水标准,出海口水质污染尤为严重.结论 东江东莞段水质主要受有机物污染,重金属污染比较少,需加强对生活污水、工业废水排放的监督以及环境的保护.

abstractsObjective To have a knowledge of water pollution situation and reasons in Dongguan section of Dongjiang River.Methods 7 sampling sections were set up in Dongguan section and the northsouth main stream of Dongjiang River.Detected and analyzed water quality in Dongguan section from 3 aspects according to The Surface Water Environment Quality Standard (GB3838-2002),including organoleptic parameters (transparency,chroma,water temperature,pH),chemical indexes (dissolved oxygen,potassium permanganate index,BOD,3-nitrogen,chromium,cadmium,lead and other 8 kinds of metal ions) and bacteriological indexes,covering a total of 26 items.Results The water quaility was neutral,the change of water temperature was obvious,and the chroma in water aggravated gradually from upstream to downstream.In the wet season,the level of dissolved oxygen was 0.04-2.26 mg/L,COD 1.49-2.83 mg/L,BOD 4.50-22.00 mg/L,ammonia nitrogen 2.40-29.84 mg/L,nitrate nitrogen 8.43-23.46 mg/L,nitrite nitrogen 0.008-0.449 mg/L,hexavalent chromium 0.500-12.714 mg/L.In the dry season,the level of dissolved oxygen was 0.62-2.30 mg/L,COD 3.75-4.86 mg/L,BOD 4.40-19.00 mg/L,ammonia nitrogen 3.98-27.99 mg/L,nitrate nitrogen 0.57-0.99 mg/L,nitrite nitrogen 42.70-83.28 mg/L,hexavalent chromium 0.336-8.609 mg/L.14 kinds of metal ions detected at 7 monitoring sites didn' t exceed standards in wet season or dry season,including cadmium,lead,arsenic,mercury,manganese,nickel,potassium,sodium,calcium,magnesium,iron,selenium,zinc and copper.The results overall showed that the upstream water quality standard went to level Ⅱ-Ⅲ,while the downstream' s went to level Ⅳ-Ⅴ,and water of the marine outfall was severely polluted.Conclusions The water in Dongguan section of Dongjiang River is mainly polluted by organics,by heavy metals at a slight degree.It is necessary to strengthen the supervision of domestic sewage,industrial wastewater emissions and protect the environment.