太湖上山水源地嗅味物质的研究与分析

Odorantin Water Resource Area of Shangshan Village in Taihu Lake Region

针对春季太湖上山村水源地嗅味物质严重超标现象（水体中2-甲基异莰醇含量超标约16 倍）,开展水源地保护区内外近10 km2范围水体与沉积物的研究分析.结果表明,水源地保护区内外水体常规理化指标达到GB3838-2002《地表水环境质量标准》中Ⅰ至Ⅱ类水质标准,水体及沉积物中营养盐和藻类并未直接影响水体嗅味,叶绿素含量在2. 0～9. 0 μg·L^-1之间,悬浮物含量在20～40 mg·L^-1 之间,大部分处于低位水平;营养盐含量接近GB 3838-2002 中Ⅱ类水标准;沉积物营养盐总氮和总磷含量最高分别达3 760 和468 mg·kg^-1,沉积物中重金属铜和锌含量最高分别达50. 1 和115 mg·kg^-1,整体含量稍高,部分点位底泥中酸性可挥发硫含量也较高,最高达5. 07 μmol·g^-1.水体和底泥中嗅味物质超标20 多倍,并呈常态趋势.富营养化引起的藻类爆发不是太湖流域春季嗅味异常的原因,而春季低温降雨引起的湖底异重流导致底泥中富集的嗅味物质向水体迁移,可能是造成水体嗅味物质增加的因素.

In the light of the situation that odorant in the water source area of Shangshan Village was quite abnormal in Spring getting far beyond the standard for water source ( 2-Methylisoborneol content in the waterbody was about 16 times higher than the criterion set in the standard) , a survey was launched of waterbodies and sediments within the range of 10 km2 around the water sources protection zone. Results show that the conventional physical and chemical properties of the waterbodies in the region met the criteria of Grade Ⅰ and Ⅱ in the Standard for Surface Water Environment ( GB 3838-2002);and in the waterbodies and sediments the nutrient salts and algae did not contribute much directly to the odor from the water;Chlorophyll varied between 2?0-9?0 g·L-1 and suspended solids between 20-40 mg·L-1 in content, and were in low levels in most of the area. The content of nutrient salts was close to the criteria of GradeⅡof GB 3838-2002;In the sediments the content of total nitrogen and total phosphorus might reach as high as 3 760 and 468 mg · kg-1 , re?spectively, and the content of Cu and Zn as high as 50?1 and 115 mg·kg-1 , respectively, and the area as a whole was a bit higher in content of the heavy metals. AVS content was also quite high in sludge, and might reach as high as 5?07μmol·g-1 . The odorant in the water and sediment were more than 20 times higher than the standard, and tended to remain so. It was found that blooming of algae caused by eutrophication of the waterbody was not the reason why abnormal odor oc?curred in the Taihu Lake region in spring; rather the low temperature and rainfalls in spring caused occurrence of density currents in the bottom of the lake, which in turn triggered release of the odorant accumulated in the sludge into the water?body. This is probably one of the explanations of why abnormal odor occurs in the Taihu Lake in spring.