滇中引水工程取水口下游金沙江生态流量研究

对拟建滇中引水工程大同取水口下游至虎跳峡前的43.5 km金沙江研究河段,采用流量历时曲线法和栖息地模拟法分别进行生态流量研究。栖息地模拟法选用目标鱼类长丝裂腹鱼,结合水动力学数值模拟与栖息地模型结合的方法,利用MIKE21建立研究河段的平面二维浅水水动力学模型。按长丝裂腹鱼对水深、流速的适宜度标准确定不同流量下的栖息地加权可利用面积(WUA),得到栖息地面积WUA随流量的变化趋势,最终确定目标鱼类产卵繁殖期适宜的生态流量值。比较2种方法的研究结果,取其中最大值作为最终生态流量值。

我国大中型水库水体自净能力特征研究

基于全国90余座大中型水库环境影响报告书的水质数据,拟合典型污染物COD、NH 3-N、TP、TN衰减系数与水位库容等因子相关曲线,对比分析我国南北方不同地区和不同规模水库的水体自净规律和水体自净能力差异及其原因。结果表明,大型、中型水库的COD衰减系数为0.001~0.32 d^(-1)和0.0018~0.27 d^(-1),NH 3-N衰减系数分别为0.0012~0.18 d^(-1)和0.0015~0.15 d^(-1);整体上,南方水库的自净能力比北方水库强,且南方水库的自净能力与地域性和类型相关,差异显著;不同水库对COD、NH 3-N等污染物的降解能力与水库正常水位库容、坝址处多年平均径流量呈正相关关系,衰减系数与水库正常水位库容、坝址处多年平均径流量相关性不显著,呈较弱的负相关关系。

Gastric emptying and plasma levels of gastrointestinal hormones in patients with peptic ulcer

IM To study the plasma level of gastrointestinal hormones and gastric emptying in patients with peptic ulcer. METHODS Thirty patients with gastric ulcer (GU), and 29 duodenal ulcer (DU) and 12 controls were studied. Plasma levels of SS, VIP and SP were measured by radioimmunoassay, and gastric emptying half time (GET1/2) was determined with TC99mresin solid meal method. RESULTS GET1/2(min) was significantly longer in GU than that in controls (659±148 vs 533±43, P<001) and plasma VIP levels (ng/L) were significantly higher than in controls (375±107 vs 184±59, P<005). There was a significant positive correlation between GET1/2 and plasma VIP levels (r=055,P<001). No significant changes were found in SS and SP in GU compared with controls (P>005). GET1/2 in DU was markedly shorter than the control group (417±102 vs 533±43, P<001), and plasma SS levels (ng/L) significantly lower than those in controls (64±25 vs 119±34,P<001), there was a significant positive correlation between GET1/2 and SS levels (r=056,P<001). Plasma SP levels (ng/L) in DU were significantly higher than the controls (544±127 vs 416±58,P<001),there was a significant negative correlation between GET1/2 and SP levels (r=-068,P<001). No significant difference was found in the plasma VIP levels between DU and controls (P>005).CONCLUSION VIP elevation may contribute to the GET1/2 delay and the occurrence of GU. The increased SP and lowered SS may play important roles in the GET1/2 acceleration and the pathogensis of DU.

提升内河航道溢油环境风险评价与管理有效性的研究

针对目前内河航道环境影响评价工作中有关溢油环境风险预测中常用计算方法,存在的局限性,提出应根据溢油扩离散、平移、输送过程和近岸地理条件变化等选择溢油扩离散模型,并依据河流流场和风场的长序列数据进行油膜漂移距离预测和事故应急响应时间计算,从而有效提高预测结果的准确性。同时,提出了河航道选址须符合饮用水水源地保护要求、建立全方位环境风险应急管理体系和监测网络、积极推动内河航道溢油应急标准体系建设、提高应急指挥决策和反应技术方案的科学性、制订应急水源供给保障方案等的内河航道溢油风险防控措施建议。

引调水工程对调蓄湖泊生态环境的影响分析

引调水工程利用天然湖泊调蓄,将引起调蓄湖泊水文情势、水质发生一定变化,对与湖泊水环境关系密切的水生生物、湖滨植被、湿地鸟类产生影响。以金沙江某提水工程方案比选阶段利用拉市海调蓄方案为例,采用图形叠置法、类比分析法、生态机理法等方法,分析工程运行对拉市海水生生物、湖滨植被、湿地鸟类的影响,为引调水工程对调蓄湖泊的生态环境影响分析提供工作思路和方法借鉴,并为类似工程方案的科学决策提供参考。