微波萃取技术在分析土壤中有机污染物的应用

介绍了微波萃取技术及其使用的试剂、设备和条件,对微波萃取在分析土壤中有机污染物的应用予以综述,阐述了微波萃取技术是分析土壤中有机污染物的好方法。     

船舶螺旋桨射流对湘江河床底泥扰动影响分析

船舶航行时螺旋桨产生的射流会对河道水流产生扰动,这种扰动是否能引起河床底泥的再悬浮需要更深入的论证分析。通过对比分析螺旋桨射流发展规律的研究成果,以湘江典型河段为研究对象,结合实船测量结果和此段河流地质资料,探讨了螺旋桨射流对湘江长株潭段河床底泥扰动的影响,并对此段河床底泥起动和悬浮条件进行了理论分析。结果表明:在周围环境流速较低的条件下,螺旋桨射流初始速度、河床水深及泥沙粒径是决定泥沙是否运动的主要因素。湘江长株潭河段已基本库区化,大部分河道平均水深远大于航道的标准水深2.8 m,河床泥沙平均粒径大于0.87 mm,其中细颗粒泥沙很少,由于螺旋桨射流断面平均流速小于泥沙起动流速,悬浮指标计算值远大于4,因此可以判断船舶正常航行在该段河流时底泥难以起动和再悬浮。     

底泥中多环芳烃(PAHs)提取方法评析

总结了底泥中多环芳烃(PAHs)提取的处理流程和国内外多种提取方法,比较了几种在我国较为常用的提取方法的效率.同时还提出了PAHs分离纯化的方法和步骤,并指出了提取过程中影响实验回收率的几个因素.     

离子化有机污染物在沉积物和水相间的平衡分配计算

本文从热力学平衡原理出发,推导出离子化有机污染物在沉积物／水相间分配系数的理论计算模型,并以苯酚,邻氯酚,２,４－二氯酚、五氯酚和苯胺的吸附实验数据为例,计算了它们在中性分子和带电荷的离子形态下的分配系数Ｋｄ和Ｋｄｉ。以及总体分配系数Ｋｄｏ研究结果表明,离子化有机污染物在沉积物和分配行为不仅与该化学物的ｐＫａ和存在形态有关。而且还取决于环境介质的ｐＨ。     

羊角月芽藻摄取磷形态的动力学研究

将湖水中的磷分成总溶解磷,溶解反应磷,总反应磷、溶解的水解性磷,溶解的光解性磷。研究其在羊角月芽过程中的变化。     

Extraction of labile metals from solid media by dilute hydrochloric acid

Extraction of labile metals from solid media is environmentally more meaningful than a total digestion. A variety of reagents have been introduced in the literature, but dilute HCl has received the greatest attention. We compare metal concentrations liberated by a dilute HCl leach with the sum of the 3-step optimized (standardized) BCR sequential extraction procedure. This is the first study to compare these procedures over a range of grain sizes. Road-deposited sediments from 10 sites in Honolulu were fractionated into six grain size classes. Aliquots of individual fractions were digested with dilute HCl, the 3-step BCR procedure (‘labile’), and a 4-acid (total) procedure. Results indicated that the weighted labile concentrations of Al, Cu, Fe, Mn, Ni, Pb and Zn were statistically greater than those from the dilute HCl leach. However, regression analysis indicated strong statistically significant relationships between the two partial extraction procedures for all metals. On a whole-sample basis, the toxicity classifications for anthropogenic-enhanced metals (Cu, Pb and Zn) were similar between extractions. Taken together, results suggest that the application of dilute HCl to solid media provides a rapid, cost-effective, and environmentally meaningful approach for contaminant monitoring.     

滇池污染底泥环保疏浚一期工程实施后环境效益评估

通过对滇池草海污染底泥环保疏浚一期工程实施前后水质、底质及水生生物的监测和分析,评价工程实施后对改善草海水质,减轻内源负荷及对水生态恢复的环境效益。结果表明,疏浚工程直接去除了草海污染底泥层,随污染层分别去除TN、TP20 538 t和1 716 t。疏浚后草海水体透明度由0.37 m提高到0.80 m,水体中的TN和TP由疏挖前的8.91 mg/L和1.07 mg/L降低到疏挖后的8.15 mg/L和0.69 mg/L。疏浚后新生界面层促使形成新的水—沉积物的平衡,水质与底质条件改善以及水下光照条件超过沉水植物恢复的需求,是疏浚后水生态呈现恢复趋势的机理。     

射阳湖浮游动物群落结构特征及其与环境因子相关性研究

2016—2017年对射阳湖开展浮游动物群落结构和水质指标逐月监测。结果表明,射阳湖共鉴定出浮游动物61种,其中原生动物、轮虫、枝角类和桡足类分别为25种、24种、7种和5种。浮游动物种类数呈现春夏季多于秋冬季的变化趋势。浮游动物优势种数量较多、分布广,群落结构相对复杂且稳定。运用Shannon-Wiener指数、均匀度指数和B/T指数对射阳湖水质作评价,结果表明,该湖处于轻度—中度污染状态,生物学指标评价法与常规水质评价结果一致。浮游动物群落结构与水质指标相关性分析表明,水温、透明度、Chl-a和DO是影响射阳湖浮游动物群落结构的主要水质指标。     

镧改性膨润土对底泥内源磷控制效果

以商业化的锁磷材料—镧改性膨润土(Phoslock?)为对象,研究了Phoslock?对磷的吸附动力学和等温线,同时研究了材料对上覆水体以及底泥内源磷释放的控制效果.结果表明,Phoslock?对磷的吸附可以用Langmuir模型拟合,相关性达到0.96,模型计算磷的最大吸附量为10.4mgP/g,且磷吸附符合拟一级和...     

Distribution and persistence of carbaryl in some terrestrial and aquatic components of a forest environment

Abstract

An oil‐based formulation of carbaryl (1‐naphthyl N‐methyl‐carbamate) (Sevin‐2‐Oil) was applied twice by a fixed‐wing aircraft at a dosage rate of 280 g of A.I./ha/application to a coniferous forest near Allardville, New Brunswick. The highest concentrations of the chemical in fir foliage, litter and forest soil 1 h after application were respectively 4.20, 1.21 and 0.59 ppm (fresh weight). The residues dissipated rapidly and the DT50 values obtained from the depletion curves were 2.3 d for foliage and 1.5 d for litter and soil samples. Very low levels (<0.1 ppm) of carbaryl persisted in foliage and litter beyond the 10 d sampling period. The maximum residue level found in stream water was 0.314 ppm and more than 50% of it had dissipated within 1 h. Low but detectable levels (0.001 ppm) of the chemical persisted in water until the end of the 10 d sampling period. Sediment samples contained a maximum level of 0.04 ppm, which dissipated below the detection limit within 5 h. Brook trout and slimy sculpins captured in the stream 1 d after the spray contained on average about 0.04 ppm of carbaryl and none of it was found in 3 d postspray samples.