Transport of oxytetracycline,chlortetracycline, and ivermectin in surface runoff from irrigated pasture

The transport of oxytetracycline, chlortetracycline, and ivermectin from manure was assessed via surface runoff on irrigated pasture. Surface runoff plots in the Sierra Foothills of Northern California were used to evaluate the effects of irrigation water application rates, pharmaceutical application conditions, vegetative cover, and vegetative filter strip length on the pharmaceutical discharge in surface runoff. Experiments were designed to permit the maximum potential transport of pharmaceuticals to surface runoff water, which included pre-irrigation to saturate soil, trimming grass where manure was applied, and laying a continuous manure strip perpendicular to the flow of water. However, due to high sorption of the pharmaceuticals to manure and soil, less than 0.1% of applied pharmaceuticals were detected in runoff water. Results demonstrated an increase of pharmaceutical transport in surface runoff with increased pharmaceutical concentration in manure, the concentration of pharmaceuticals in runoff water remained constant with increased irrigation flow rate, and no appreciable decrease in pharmaceutical runoff was produced with the vegetative filter strip length increased from 30.5 to 91.5 cm. Most of the applied pharmaceuticals were retained in the manure or within the upper 5 cm of soil directly beneath the manure application sites. As this study evaluated conditions for high transport potential, the data suggest that the risk for significant chlortetracycline, oxytetracycline, and ivermectin transport to surface water from cattle manure on irrigated pasture is low.     

Comparison of Indexes for Prioritizing Placement of Water Quality Buffers in Agricultural Watersheds1

Dosskey, Michael G. and Zeyuan Qiu, 2011. Comparison of Indexes for Prioritizing Placement of Water Quality Buffers in Agricultural Watersheds. Journal of the American Water Resources Association (JAWRA) 47(4):662‐671. DOI: 10.1111/j.1752‐1688.2011.00532.x Abstract: Five physically based, spatially distributed, empirical indexes were compared for the degree to which they identified the same or different locations in watersheds where vegetative buffers would function better for reducing agricultural nonpoint source pollution. All five indexes were calculated on a 10 m × 10 m digital elevation grid on agricultural land in the 144‐km² Neshanic River watershed in New Jersey. The indexes included the topography‐based Wetness Index (WI) and Topographic Index (TI) and three soil survey‐based indexes (sediment trapping efficiency [STE], water trapping efficiency [WTE], and groundwater interaction [GI]). Results showed that each index associated higher pollution risk and mitigation potential to a different part of the landscape. The WI and TI identified swales and riparian areas where runoff converges, whereas STE and WTE identified upland sites. The STE and WTE lack the fine scale of slope resolution and the accounting for convergent runoff patterns that can be important for properly locating buffers in some watersheds. The GI index indicates the existence of a shallow water table but the correspondence with WI‐ and TI‐identified sites was only modest. For watersheds where pollutant loading is generated by both saturation‐excess (emphasized by TI and WI) and infiltration‐excess processes (emphasized by STE and WTE), the indexes could be complementary. However, techniques would be needed for properly apportioning priority among sites identified by each index.     

太湖流域源头南苕溪河口生态工程恢复及其初期水质净化效应

针对太湖流域源头溪流农业面源污染严重和生态拦截净化较弱的问题,采用生态工程措施于南苕溪人青山湖水库河口处对河道进行恢复.综合考虑山溪性河流水文水动力特征,通过构建、稳定和保护河口与滨岸带生态系统实现河道恢复目标.所采用关键技术包括:合金钢网石兜抛石技术、深潭-浅滩/塘-洼地组合净化技术、分流沙嘴技术、T-型乱石抛筑透水坝技术、河岸侵蚀面防侵蚀的浅滩沙洲场技术、植被缓冲带技术、水生植物恢复技术等.对河口生态工程区进行连续9个月的监测结果显示,工程区上段浅滩及分流沙嘴区能有效复氧,提升pH值并降低电导率,同时对总磷、活性磷和悬浮颗粒物有较好的去除效果;中段深潭区通过强化的微生物活性能有效去除铵态氮与亚硝态氮;下游T-型坝能较好地拦截并沉积河口冲刷物质,但需对其定期清理以防引发二次污染.河口生态工程运行初期较好地改善了河道结构并提升了河流自净能力,对河流生态恢复最具指示作用的水质指标溶解氧饱和度、铵态氮去除率在工程实施后较工程实施前平均分别提高了14.5％、14.7％.     

一种门窗五金件用冷轧窄带钢的轧制新工艺

详细介绍了一种用圆钢线材经处理 ,轧制、热处理、精轧成门窗五金件生产用圆盘窄带钢的新生产工艺和设备 ,以提高窄带钢轧制精度、表面质量 ,减少设备投资 ,同时介绍了国内外的应用情况。     

Grass‐Shrub Riparian Buffer Removal of Sediment,Phosphorus, and Nitrogen From Simulated Runoff1

Abstract: Riparian buffer forests and vegetative filter strips are widely recommended for improving surface water quality, but grass‐shrub riparian buffer system (RBSs) are less well studied. The objective of this study was to assess the influence of buffer width and vegetation type on the key processes and overall reductions of total suspended solids (TSS), phosphorus (P), and nitrogen (N) from simulated runoff passed through established (7‐year old) RBSs. Nine 1‐m RBS plots, with three replicates of three vegetation types (all natural selection grasses, two‐segment buffer with native grasses and plum shrub, and two‐segment buffer with natural selection grasses and plum shrub) and widths ranging from 8.3 to 16.1 m, received simulated runoff having 4,433 mg/l TSS from on‐site soil, 1.6 mg/l total P, and 20 mg/l total N. Flow‐weighted samples were collected by using Runoff Sampling System (ROSS) units. The buffers were very efficient in removal of sediments, N, and P, with removal efficiencies strongly linked to infiltration. Mass and concentration reductions averaged 99.7% and 97.9% for TSS, 91.8% and 42.9% for total P, and 92.1% and 44.4% for total N. Infiltration alone could account for >75% of TSS removal, >90% of total P removal, and >90% of total N removal. Vegetation type induced significant differences in removal of TSS, total P, and total N. These results demonstrate that adequately designed and implemented grass‐shrub buffers with widths of only 8 m provide for water quality improvement, particularly if adequate infiltration is achieved.     

TRACE ELEMENTS IN NORTHERN GREAT PLAINS STRIP MINE AND LIVESTOCK IMPOUNDMENT WATER1

ABSTRACT: The water from 32 strip mine water impoundments and nine livestock watering ponds in North Dakota, South Dakota, and Wyoming were analyzed for trace elements. Because of the high concentrations of trace elements in coal and bentonite clay, the possibility exists for these elements to dissolve or be suspended in the water. Strip mine ponds were not significantly higher in trace element concentrations compared to livestock ponds. All but one of the 41 ponds sampled contained elemental concentrations that would be detrimental for livestock use or aquatic life use. Cadmium and lead were the elements most frequently in excess of water quality crieria. Lead was found in the study ponds about 35 times the median concentration of North American rivers. Manganese concentrations were found to exceed iron in many ponds, which is unusual in natural waters. The potential for detrimental concentrations of trace elements in pond water must be evaluated when designing land use management plans for ponds intended to be used by livestock or aquatic life.     

密度场干涉测量及其条纹处理计算

本文将普通纹影仪改造成激光差分干涉仪,并用于火焰等密度场的显示与测量。编制了条纹预处理和细化软件系统,并对干涉条纹进行了处理和细化计算。另外,针对细化后的条纹,编制了密度场的计算软件,并对蜡烛火焰和超声速轴对称绕流流场进行了计算,得到了密度场定量的结果。     

一种能原位检测类雌激素暴露的胶体金免疫检测试片

利用免疫层析和胶体金标记技术试制出一种免疫检测试片,该试片可快速定性检测鱼体内诱导的卵黄蛋白原.试验结果表明,该检测试片仅需采鱼血浆100μL,15min内便可获得检测结果.试片的检测限(LODVTG)为10μg·mL-1,野外现场应用表明测量准确度达92%.因此,该试片可用于野外水体类雌激素暴露与影响的原位评价.     

酶底物法与多管发酵法和纸片法监测环境水样大肠菌群的比较

用标准菌株对比了酶底物法和多管发酵法及快速纸片法,监测分析了分组环境水样中的大肠菌群。结果表明,酶底物法操作快速、简单、结果稳定、无二次污染,能满足水质监测和应急监测的需求。     

桉树人工林地力衰退防治研究──改全垦为带垦

主要讨论了桉树造林整地方式──全垦与带垦对桉树生长的影响,以及对土壤侵蚀、土壤养分和土壤物理性质的影响．研究结果表明,改全垦为带垦对防止桉树人工林地力衰退有积极作用．