Spatial and Seasonal Response of Municipal Water Use to Weather across the Contiguous U.S.

Weather variability has the potential to influence municipal water use, particularly in dry regions such as the western United States (U.S.). Outdoor water use can account for more than half of annual household water use and may be particularly responsive to weather, but little is known about how the expected magnitude of these responses varies across the U.S. This nationwide study identified the response of municipal water use to monthly weather (i.e., temperature, precipitation, evapotranspiration [ET]) using monthly water deliveries for 229 cities in the contiguous U.S. Using city‐specific multiple regression and region‐specific models with city fixed effects, we investigated what portion of the variability in municipal water use was explained by weather across cities, and also estimated responses to weather across seasons and climate regions. Our findings indicated municipal water use was generally well‐explained by weather, with median adjusted R² ranging from 63% to 95% across climate regions. Weather was more predictive of water use in dry climates compared to wet, and temperature had more explanatory power than precipitation or ET. In response to a 1°C increase in monthly maximum temperature, municipal water use was shown to increase by 3.2% and 3.9% in dry cities in winter and summer, respectively, with smaller changes in wet cities. Quantifying these responses allows urban water managers to plan for weather‐driven variability in water use.     

Measuring bed shear stress along vegetated river beds using FST-hemispheres

The measurement of the bed shear stress along vegetated river beds is essential for accurately predicting the water level, velocity and solute and sediment transport fluxes in computational hydroenvironmental models. Details are given herein of an experimental and theoretical study to determine the bed boundary shear stress along vegetated river beds introducing a novel field measuring method, namely the FliessWasserStammtisch (FST)-hemispheres. Although investigations have been conducted previously for sedimentary channels using the FST-hemispheres, this preliminary study is thought to be the first time that such hemispheres have been used to investigate the bed shear stresses in vegetated channels. FST-hemispheres were first developed by Statzner and Müller [1989. Standard hemispheres as indicators of flow characteristics in lotic benthos research. Freshwater Biology 21, 445-459] to act as an integrated indicator of the gross hydrodynamic stresses present near the bed. Test and validation data were found to be at least of the same order of magnitude for the stresses predicted from literature for sedimentary channels, with this study establishing the commencement of a database of calibrated FST-hemisphere laboratory data for vegetated channel beds. In a series of experiments, depths ranging from 0.1 to 0.28m were considered, equating directly to comparable conditions in small rivers or streams. The results of this study provide a basis for enabling the FST-hemispheres to be used to evaluate the boundary shear stress for a wider range of applications in the future, including vegetated river beds.     

Monitoring of Butter and Ghee (Clarified Butter Fat) for Pesticidal Contamination from Cotton Belt of Haryana, India

Butter (45) and ghee (55) samples were collected from rural and urban areas of cotton growing belt of Haryana and analysed for detecting the residues of organochlorine, synthetic pyrethroid and organophosphate insecticides. The estimation was carried out by using multi residue analytical technique employing GC-ECD and GC-NPD systems equipped with capillary columns. Butter samples were comparatively more contaminated (97%) than ghee (94%), showing more contamination with organochlorine insecticides from urban samples. About 11% samples of butter showed endosulfan residues above MRL value and 2% samples had residues of synthetic pyrethroids and organophosphates each above their respective MRL values. In ghee, residues of HCH & DDT both and of endosulfan exceeded the MRL values in 5 and 20% samples, respectively. Among organophosphates, only chlorpyriphos was detected with 9% samples showing its residue above MRL value. Irrespective of contamination levels, residues above the MRL values were more in ghee. More extensive study covering other agricultural regions/zones of Haryana has been suggested to know the overall scenario of contamination of milk products.     

毛细管气相色谱法测定烟草中有机氯农药残留

研究了烟草中六六六及滴滴涕异构体含量的气相色谱分析方法.样品以石油醚 丙酮在索氏提取器中提取,提取液以浓硫酸净化.采用DB-5弹性石英毛细管柱分离样品,GC-ECD检测农药六六六、滴滴涕的残留量.方法的线性范围为2.27×10-13～7.66×10-11g;最小检测量为1.3×10-8～3.0×10-7 μg,加标平均回收率为95.3%～103.3%,RSD为2.8%～4.5%.     

Monitoring of Seasonal Vegetables for Pesticide Residues

Market samples (60) of six seasonal vegetables were monitoredduring 1996–1997 to determine the magnitude of pesticidalcontamination. The estimation of insecticide residuesrepresenting four major chemical groups i.e. organochlorine,organophosphorous, synthetic pyrethroid and carbamate, was doneby adopting a multiresidue analytical technique employingGC-ECD and GC-NPD systems with capillary columns. The testedsamples showed 100% contamination with low but measurableamounts of residues. Among the four chemical groups, theorganophosphates were dominant followed by organochlorines,synthetic pyrethroids and carbamates. About 23% of the samplesshowed contamination with organophosphorous compounds abovetheir respective MRL values. More extensive studies coveringdifferent regions of Haryana state are suggested to get a clearidea of the magnitude of vegetable contamination with pesticideresidues.     

气相色谱-质谱法测定废酸油渣中的16种多环芳烃

建立了废酸油渣中16种多环芳烃超声萃取、Florisil萃取柱净化、气相色谱-质谱测定的方法。笔者对提取方式、提取剂类型和体积、提取时间和次数、净化方式等进行研究,采用无水硫酸钠分散,二氯甲烷作为提取剂超声40 min,提取液经纯水清洗、离心后取适量有机相经过3 g Florisil萃取柱净化,采用气相色谱-质谱选择离子模式(SIM),加入内标进行定量分析。结果表明:二氯甲烷提取效率比正己烷好,丙酮可能引起酸性样品中多环芳烃的降解,丙酮超声萃取时加入无水硫酸钠能在一定程度上防止目标物降解,但萃取效率不可控制,宜采用二氯甲烷作为萃取剂。分散提取能有效减少提取时间,超声清洗仪超声40 min提取效率为86.2%～104%。3g Florisil萃取柱净化比1 g Florisil萃取柱净化和GPC净化效果略好。方法检出限为0.4～1.3 mg/kg,6次空白加标的相对标准偏差为2.3%～15.3%,6个实际样品测定结果的相对标准偏差为1.2%～27.3%,基体加标回收率为51.3%～126%,连续校准稳定。该方法适用于废酸油渣样品中16种多环芳烃的检测,比直接溶解有效,比加速溶剂萃取、索氏提取、微波萃取和超声探头萃取简单、快捷,能有效减少设备污染和腐蚀,净化方法有效,测定结果准确可靠,是实现大批量样品检测的可行方法。     

工业纤维废渣利用的生物技术研究

用平板分离法从树皮中选育出“５０８８号菌种”，使麻纺厂的废弃下脚料转化成可替代饲料中玉米成份的“媲谷菌饲”。并利用造纸厂白泥，粘胶纤维厂废水处理产生的污泥作饲料钙，锌元素添加剂获成功。     

对熏烟扩散模式应用的探讨

工程上应用的大气污染物扩散模式中 ,熏烟模式由于其非定常性而与其他扩散模式有很大的区别。正确处理模式中各参数及变量的相互关系才能客观地反映污染物对环境影响的结果。本研究通过对熏烟模式的非定常性和各参数、变量相互关系的分析 ,提出了正确使用该模式的方法