Spatial variations in daily average CO2 concentrations above wetland surface of Xianghai National Nature Reserve, China

Horizontal and vertical variations of daily average CO2 concentration above the wetland surface were studied in Xianghai National Nature Reserve of China in August, 2000. The primary purpose was to study spatial distribution characteristics of CO2 concentration on the four levels of height(0.1 m, 0.6 m, 1.2 m and 2 m) and compare the differences of CO2 concentration under different land covers. Results showed that daily average CO2 concentration above wetland surface in Xianghai National Natural Reserve was lower than that above other wetlands in northeast China as well as the worldwide average, suggesting that Xianghai wetland absorbed CO2 in August and acted as“sink” of CO2. The horizontal variations on the four levels of height along the latitude were distinct, and had the changing tendency of“decreasing after increasing” with the increase of height. The areas with obvious variations were consistent on different levels of height,and those with the highest variations appeared above surface of shore, sloping field, Typha wetland and Phragmites wetland; the vertical variations were greatly different, with the higher variations in Phragmites wetland and Typha wetland, and the lands near the shore and the sloping field with the lower variations. Spatial variations of daily average CO2 concentrations above wet!and surface were affected by surface qualities and land covers.     

Application of compost in agricultural practice could potentially cause contamination of foodstuffs with pathogenic bacteria such as Escherichia coli O157:H7. This study investigated pathogenic bacteria in compost collected from the compost facilities, an

IntroductionIncreasing public interests have been concerned onsafety foods and the environmental aspects recently,especially on the so-called organic foods , which are madefromcrops grown with organic fertilizers or compost but notchemical fertilizers .Pu…     

污泥活性炭对染料的吸附动力学研究

以城市污水处理厂脱水污泥作为原料,采用化学活化法(ZnCl2作为活化剂)制得污泥活性炭,全面研究了污泥活性炭对活性艳红K-2BP、酸性大红GR和直接紫N这3种染料的吸附动力学行为.结果表明,污泥活性炭可以有效地吸附染料,实现污泥的资源化;3种染料的平衡吸附量qe均随着染料初始浓度和温度的增大而增大,相同条件下平衡吸附量qe的大小顺序为:酸性大红GR＞活性艳红K-2BP＞直接紫N;伪二级动力学模型能够很好地描述3种染料在污泥活性炭上的吸附动力学行为;对于活性艳红K-2BP和直接紫N,颗粒内扩散过程是该吸附速率的控制步骤,但不是唯一的速率控制步骤,吸附速率同时还受颗粒外扩散过程的控制,而对于酸性大红GR,颗粒内扩散过程不是吸附速率的控制步骤;污泥活性炭对3种染料的吸附是一个吸热过程,吸附活化能较小,主要为物理吸附过程.     

稀有鮈鲫在鱼类胚胎急性毒性试验中的适用性研究

为了验证我国本土鱼种稀有鮈鲫（Gobiocypris rarus）在鱼类胚胎急性毒性试验的适用性，评价其在鱼类替代试验中的应用潜力，选取3，4-二氯苯胺和五水硫酸铜，按照《OECD化学品测试准则No.236鱼类胚胎急性毒性试验》，分别开展6次稀有鮈鲫胚胎急性毒性试验，通过评价试验结果的重复性，验证稀有鮈鲫是否适用于鱼类胚胎急性毒性试验.结果表明:3，4-二氯苯胺和五水硫酸铜对稀有鮈鲫胚胎的96 h LC₅₀（96 h半数致死浓度）平均值（x）分别为12.8和1.76 mg/L，标准差（s）分别为1.70和0.197 mg/L；变异系数（CV）分别为13.3%和11.2%，均小于30%；两种化学品6次试验的96 h LC₅₀均在各自x±2s范围内.研究显示，稀有鮈鲫胚胎的形态特征、发育过程及孵化时间等生物学特征均与斑马鱼类似，3，4-二氯苯胺和五水硫酸铜这两种化学品的胚胎急性毒性试验结果具有良好的重复性，其敏感性也与成鱼类似.因此，稀有鮈鲫作为一种我国本土的标准试验鱼种，具有鱼类胚胎急性毒性试验的应用潜力.      

污水生物处理过程中的同步硝化反硝化研究概况

在好氧生物氧化过程中通过控制反应器内 DO浓度、C/N比、污泥负荷的条件下 ,观察到较明显的同步硝化反硝化现象 ,通过控制反应条件 ,可使硝化、反硝化速率都得以同步提高。     

聚合氯化铝与有机高分子复合絮凝剂的形态分布研究——AlFerron和~(27)AlNMR相结合

主要研究了Ａｌ－Ｆｅｒｒｏｎ逐时络合比色法和＾２７Ａｌ－ＮＭＲ法应用于聚合铝与有机高分子复合絮凝剂形态分布的测定，结果表明，两种方法分别测定的Ａｌｂ和Ａｌ１３的结果具有一定的相关性；聚合铝与有机高分子复合后其形态分布发生了一定的变化，Ａｌｂ（或Ａｌ１３）的含量有所降低，但仍是优势形态，Ａｌａ（或Ａｌ单）的含量基本保持不变。     

垃圾填埋场内部CH4浓度随时间的变化特征及其模拟

通过对佛山市五峰垃圾填埋场内部部分时段CH4浓度的监测 ,分析了在填埋场内部垃圾发酵过程中CH4浓度随时间的动态变化特征 ,提出了利用某些统计曲线分别模拟或综合模拟CH4浓度随时间的变化过程的方法 .应用表明 ,本方法可以较准确地预测垃圾发酵主要时段内的CH4浓度随时间的变化 ,仅在垃圾发酵的尾声阶段 ,模拟浓度与实测浓度有少许出入 .     

Fluoride distibution and the effect of some ions along Alexandria coastal Mediterranean seawater of Egypt

The coastal seawater of Mediterranean of Alexandria receives large amount of discharged waters containing industrial wastes, sewage, and agricultural and domestic drainage. Fluoride and some parameters were(chemical and physical) determined. The data gave indication that the content and the amount of the discharged water largely affect the chemical composition of the coastal water. Stepwise regression analysis was highly significant and the model was very fruitful, where the observed and calculated values were mostly concordant. This may indicated that there was a relation between fluoride content in coastal seawater and its content in the discharged water.     

液体化工罐区静电产生的原因及防范措施

对液体化工罐区静电产生的原因及可能产生的严重危害性做了详细的分析,并提出了防范措施.     

活性污泥作为气化用型煤粘结剂的研究 Ⅰ.污泥添加量和型煤成型条件的考察

以活性污泥为研究对象，以合成氨厂广泛使用的白泥型煤参照，进行了气化用型煤粘结剂的研究，结果表明，当污泥添加量为２％白泥添加量为０．３％时，所制得的型煤抗压强度、跌落强度、热稳定性与白泥型相当。