Effects of Nutrient Source and Supply on Crude Oil Biodegradation in Continuous-Flow Beach Microcosms

Ammonium and nitrate were used as nitrogen sources to support microbial biodegradation of crude oil in continuous-flow beach microcosms to determine whether either nutrient was more effective in open systems, such as intertidal shorelines. No differences in the rate or extent of oil biodegradation were observed, regardless of whether these nutrients were provided continuously or intermittently. Nutrients were provided once every two weeks to intermittent-input microcosms and washed out within four to five days. In continuous-input microcosms, ammonium and nitrate were assimilated as quickly as they were provided during the first week, but both accumulated to greater than 10?mg?N/L thereafter. The sensitivity of the oil mineralization rate to nutrient input decreased rapidly as the extent of oil degradation increased, and after about two weeks the rate of oil-mineralization appeared to be independent of nutrient input. Therefore, there may be little value in maintaining a long-term supply of nutrients in contact with oil-contaminated sediments. The rates of microbial assimilation of ammonium and nitrate followed similar trends. Both compounds were assimilated more slowly as the extent of oil biodegradation increased, and the nitrate uptake rates approached zero after about two weeks. Ammonium assimilation continued at a low rate throughout the six-week experiment, but this did not appear to affect the rate of oil mineralization. Assimilation of ammonium resulted in a sharp decrease in the pH of the synthetic seawater that was pumped continuously through the microcosms, but nitrate had a much smaller effect on pH. The magnitude of the ammonium-associated pH change was never as large as was observed in previous studies involving oil biodegradation in batch reactors, however, and did not affect the oil-biodegradation rate.     

Field Study of the Ability of Two Grassed Bioretention Cells to Reduce Storm-Water Runoff Pollution

Two grassed bioretention cells including internal storage zones (ISZs) were monitored for 16?months in central North Carolina. Each cell had a surface area of 106?m2 and fill media depths were 0.75 and 1.05?m for the north (North) and the south (South) cells, respectively. Asphalt parking lot inflow and outflows were analyzed for nitrogen and phosphorus forms and fecal coliform (FC). Outflow volumes and peak flows for individual storms were generally less than those of inflow. Overall, except for NO2,3–N, effluent nitrogen species event mean concentrations (EMCs) and loads were significantly (α = 0.05) lower than those of the inflow, and nitrogen species load reductions ranged from 47 to 88%. Apart from fall and winter, during which a longer hydraulic contact time seemed to be needed, the ISZs appeared to improve denitrification. Total phosphorus (TP) and OPO4-P EMCs were significantly lower than those of the inlet. Reductions were 58% (South) and 63% (North) for TP and 78% (North) and 74% (South) for OPO4–P. There was no significant difference in TP and OPO4–P loads between the inlet and the two outlets. Moreover, effluent concentrations for both phosphorus species were low, relative to other studies. The best nutrient EMC and load reductions occurred during the warm and humid seasons. When considering effluent concentrations in addition to removal rates, the grassed cells showed promising results for FC and nutrient pollution abatement when compared to conventionally vegetated bioretention (trees, shrubs, and mulch) previously studied in North Carolina.     

二维洪水演进数值模拟研究

本文在内蒙古包头市北梁区荒漠化土壤的质地和养分元素含量分析的基础上,与包头市大量堆积的、严重威胁环境的三种固体废弃物(粉煤灰、水库淤积物和污水沉淀物)进行了对比研究。结果表明:该三种废弃物具有细粒、富含植物生长所必需之养分元素的特点。以该区荒漠化土壤作基本土壤,三种废弃物作土壤添加剂进行了玉米、沙棘树和草坪草的种植实验,结果显示:(1)三种废弃物添加到荒漠化土壤中,能够显著增加土壤的养分含量。(2)荒漠化土壤被改造成为近轻壤土的砂壤土或轻壤土。(3)改良后的土壤能够显著增加土壤的生物生产量。     

畜禽鱼虾肉在‒18 ℃冻藏过程中营养价值的变化

冷藏是市场及居民普遍使用的肉类贮藏方法,在冷藏过程中肉会发生一些品质和营养方面的变化。本研究选择-18℃冷藏条件,以典型畜禽鱼虾肉为研究对象,选取猪、牛、羊、鸡、鱼和虾共六类肉样,通过厂家直供、超市和农贸市场途径共计采集16个样品。在冷藏过程中,每隔一段时间取出一包肉样品,对其各种指标进行测定和记录,研究肉品在冷藏期间发生的品质变化。实验结果表明,在-18℃下贮藏到360天,随着贮藏时间的延长,各种肉的感官评分均呈现下降趋势,肉的鲜度不断下降,畜禽肉评分均在6分及以上,鱼虾肉已低于6分。肉样品的pH值和水分含量均在标准范围内波动;蛋白质、脂肪及脂肪酸等营养成分含量均在小范围内波动,无明显变化趋势。     

营养素及相关物质风险评估

营养素物质摄入超过某个上限值时,也能导致不良健康作用,其潜在危害可以通过风险评估描述.但一定量的营养素摄入又是机体正常功能所必需的,新的评估模型应充分考虑营养素物质的特殊性.目前,安全摄入上限(UL)法是国际上广泛接受的营养素物质风险评估方法.对于尚未发现不良作用的营养素物质,FAO/WHO提出了所观察到的最高摄入量(HOI)的概念.对于不存在无风险摄入量水平、风险摄入量水平与生物所需摄入量水平有重叠的营养素物质,亟待在UL法的基础上进一步研究其风险评估方法.本文就上述各类营养素物质的风险评估做一简要综述.     

预包装食品营养标签现况调查

目的了解我国现有预包装食品营养成分表、营养声称和营养成分功能声称的标示现况。方法通过现场调查方法,在北京和上海大型超市用照相机拍照、抄写及购买的方式记录标签标识状况。结果输入计算机,用SPSS13.0进行统计分析。结果食品营养标签标示率为59.5%;核心营养成分营养素参考值(NRV%)的标示率按《食品营养标签管理规范》标识后超过50%;营养声称标示率为40%;营养成分功能声称标示率为16.9%;不同类食品间标示率存在较大差别;标识营养素的名称和单位不统一。结论与2008年《食品营养标签管理规范》发布前相比,预包装食品营养标签标示有所增加,但营养标签标识尚不规范,政府应加强食品营养标签的监督检查。     

Utility of Column Lysimeter for Design of Soil Aquifer Treatment System for Wastewater Renovation Using Artificial Neural Networks

An artificial neural network (ANN) model is developed to study the correlation of data with reference to various wastewater pollution parameters (biochemical oxygen demand, chemical oxygen demand, suspended solids, NH4, PO4) using two scales of experiments viz. column lysimeter and a pilot soil aquifer treatment (SAT) system for wastewater renovation in India. A unique feature of the study is that the primary treated wastewater was directly applied to SAT system for renovation in contrast to the secondary treated effluent used in most of the other studies that have been reported. The analysis of data using ANN as a tool indicates that the column lysimeter data are useful for design of SAT systems and it is possible to predict the effluent quality for SAT system based on the inputs from lysimeter experiments. The study highlights the utility of column lysimeter studies for evolving design parameters for a full-scale SAT system thereby obviating the need for pilot SAT studies which are site specific, time consuming, and expensive. Thus, the study suggests that the experimental data from lysimeter studies at a particular site can be used to predict performance of field-scale SAT systems without going in for actual experimentation. Further, the field data from one site could be utilized for design of SAT systems at other locations provided the climatic and hydrogeological conditions viz. soil matrix characteristics and wastewater characteristics, etc., are similar.     

Genetic Variation in Primary Metabolites of Pastinaca sativa; Can Herbivores Act as Selective Agents?

Although insect herbivory has been shown to act as a selective agent on plant secondary metabolism, whether primary metabolites contribute to resistance and can respond to selection by herbivores remains untested. In the wild parsnip (Pastinaca sativa), its principal herbivore, Depressaria pastinacella, acts as a selective agent on furanocoumarin resistance factors. In this study, we determined whether webworms can, by causing differential reductions in fitness, act as selective agents on parsnip primary metabolites. Estimates of narrow-sense heritabilities were significantly different from zero for C18 fatty acids in buds and developing fruits, fructose and sorbitol in buds, fructose, myo-inositol, bergapten, and psoralen in fruits. Wild parsnips protected from webworms by insecticide produced 2.5 times as much seed biomass as unsprayed plants; that webworms accounted for this difference in plant fitness was indicated by a significant negative relationship between reproductive effort and an index of webworm damage. Only a handful of metabolites influenced resistance to webworms; these included osthol, sorbitol, and protein in developing fruits as well as previously documented furanocoumarins. Osthol, a coumarinic compound, enhanced resistance, as did protein content, while sorbitol lowered resistance. Other primary metabolites may affect resistance to webworms, but their effect was context-dependent, that is, their effect depended on concentrations of other metabolites (epistasis). Susceptible plant phenotypes were found to have average chemical compositions. Although there was genetic variation in some of the primary metabolites in parsnips, the epistatic nature of their involvement in resistance and the lack of genetic variation in some suggest that selection on them from webworms will be either inconsistent or ineffective.     

Long-term impacts of pasture irrigation with treated sewage effluent on nutrient status of a sandy soil in Zimbabwe

Declining freshwater resources and the need to safely dispose wastewater have led to a rapid increase in wastewater reuse in developing countries. However, empirical evidence on the effects of effluent-irrigation on soil fertility is limited. The study investigated the nutrient status of a sandy soil after 26 years of effluent irrigation. Soil samples from effluent-irrigated and non-irrigated sites were analysed for pH, electrical conductivity (EC), soil organic carbon (SOC), total and plant available forms of N and P, exchangeable bases and trace metals. Analysis of effluent quality showed that, besides Cr and Cd, all measured parameters were within acceptable limits for wastewater irrigation. Our results revealed that effluent-irrigation significantly (P < 0.05) enriched the soil with essential nutrients for plant growth, which are commonly deficient in most soils of Zimbabwe. Effluent-irrigated soils had significantly (P < 0.05) higher pH, EC, SOC, total and available N and P and, exchangeable Ca and Mg at 0–30 cm-depth. However, apart from Cr accumulation, effluent irrigation significantly (P < 0.05) depleted Zn, Cu and Cd probably due to plant uptake and enhanced mobility under acidic soil pH. Cr accumulation and depletion and mobility of Zn, Cu and Cd in effluent-irrigated soils could threaten the sustainability of the practice. We recommend a review of the current management practices based on crop water requirements, effluent quality and environmental considerations.     

玫瑰花营养保健成分分析及花青素稳定性研究

通过天然产物系统研究方法,对玫瑰花进行系统预试,对其中的活性成分作出初步定性判断。同时,按照国标方法对玫瑰花部分营养保健成分进行定量测定,结果发现玫瑰花呈弱酸性,可能含有酚类化合物、鞣质、糖、多糖和苷、甾体、花青素、维生素C、生物碱等化学成分,不含强心苷、蒽醌类化合物。分析得花青素为玫瑰花红的主要成分,并对花青素稳定性进行比较研究,结果显示光照对花青素稳定性影响最小;酸性条件下,温度越低,酸性花青素越稳定。