油烟中存在的高极性有机化合物

城区总悬浮物中油烟（肉类熟调释放的浮尘）占有相当比重。在目前研究中，将油烟中存在的极性有机化合物转化成三甲基硅（烷）衍生物，并用气相色谱／质谱测定仪分析。硅化能够使油烟萃取物中单酸甘油脂的检测得以实现，同时能够使胆固醇的检测得以提高。我们对加州贝允斯费尔德收集的大气微样品不的化合物进行检测，其丰度显示出大气与油烟来源样品高度一致。数据说明饱和单酸甘油脂和胆固醇适合用作油烟的示踪物。     

Similar policing rates of eggs laid by virgin and mated honey-bee queens

Worker-policing is a well-documented mechanism that maintains functional worker sterility in queenright honey-bee colonies. Unknown, however, is the source of the egg-marking signal that is thought to be produced by the queen and used by policing workers to discriminate between queen- and worker-laid eggs. Here we investigate whether mating is necessary for the queen to produce the egg-marking signal. We compare the removal rate of eggs laid by virgin queens and compare this rate with that of eggs laid by mated queens. Our results show that mating does not affect the acceptability of eggs, suggesting that physiological changes linked to the act of mating do not play a role in the production of the queens egg-marking signal.     

Evaluation of vacuum and wet-wipe methods for removal of World Trade Center dust from indoor environments

The destruction of the buildings at the World Trade Center (WTC) complex dispersed dust and debris into the surrounding area. Pulverized building material made up most of the fallout and was intermixed with combustion byproducts of the aircraft and building contents. A study was conducted to confirm the effectiveness of several cleaning procedures in removing WTC-related contamination from lower Manhattan residences. The contaminants included asbestos, lead, dioxin/furans, synthetic vitreous fibers (fibrous glass), and crystalline silica. All cleaning procedures included the common elements of vacuuming and wet wiping with soap and water. This cleaning procedure combination is effective in reducing WTC-related contamination to below health-based benchmarks. Post-cleaning environmental test results suggested that airborne asbestos measurements can be used as a surrogate parameter in clearance determinations.     

Lime as the source of PCDD/F contamination in citrus pulp pellets from Brazil and status of the monitoring program

After an exhaustive investigation, in 1997 the source of the milk contamination in Germany was traced to citrus pulp pellets originating from Brazil. It has been shown that lime was the source of the PCDD/F contamination of these products. After this conclusion, a continuous monitoring program has been performed over a two year period and the results are presented in this paper. Standard isotope dilution techniques were used for all samples, which were analyzed by selected ion monitoring high resolution GC–MS.     

Design of aquifer remediation systems: (2) estimating site-specific performance and benefits of partial source removal

A Lagrangian stochastic model is proposed as a tool that can be utilized in forecasting remedial performance and estimating the benefits (in terms of flux and mass reduction) derived from a source zone remedial effort. The stochastic functional relationships that describe the hydraulic "structure" and non-aqueous phase liquid (NAPL) "architecture" have been described in a companion paper (Enfield, C.G., Wood, A.L., Espinoza, F.P., Brooks, M.C., Annable, M., Rao, P.S.C., this issue. Design of aquifer remediation systems: (1) describing hydraulic structure and NAPL architecture using tracers. J. Contam. Hydrol.). The previously defined functions were used along with the properties of the remedial fluids to describe remedial performance. There are two objectives for this paper. First, is to show that a simple analytic element model can be used to give a reasonable estimate of system performance. This is accomplished by comparing forecast performance to observed performance. The second objective is to display the model output in terms of change in mass flux and mass removal as a function of pore volumes of remedial fluid injected. The modelling results suggest that short term benefits are obtained and related to mass reduction at the sites where the model was tested.     

The Rossby Centre Regional Atmospheric Climate Model part I: model climatology and performance for the present climate over Europe

The Rossby Centre Atmospheric Regional Climate Model (RCA2) is described and simulation results, for the present climate over Europe, are evaluated against available observations. Systematic biases in the models mean climate and climate variability are documented and key parameterization weaknesses identified. The quality of near-surface parameters is investigated in some detail, particularly temperature, precipitation, the surface energy budget and cloud cover. The model simulates the recent, observed climate and variability with a high degree of realism. Compensating errors in the components of the surface radiation budget are highlighted and the fundamental causes of these biases are traced to the relevant aspects of the cloud, precipitation and radiation parameterizations. The model has a tendency to precipitate too frequently at small rates, this has a direct impact on the simulation of cloud-radiation interaction and surface temperatures. Great care must be taken in the use of observations to evaluate high resolution RCMs, when they are forced by analyzed boundary conditions. This is particularly true with respect to precipitation and cloudiness, where observational uncertainty is often larger than the RCM bias.     

Model development for nutrient loading estimates from paddy rice fields in Korea

A field experiment was performed to evaluate water and nutrient balances in paddy rice culture operations during 2001-2002. The water balance analysis indicated that about half (50-60%) of the total outflow was lost by surface drainage, with the remainder occurring by evapotranspiration (490-530 mm). The surface drainage from paddy fields was mainly caused by rainfall and forced-drainage, and in particular, the runoff during early rice culture periods depends more on the forced-drainage due to fertilization practices. Most of the total phosphorus (T-P) inflow was supplied by fertilization at transplanting, while the total nitrogen (T-N) inflow was supplied by the three fertilizations, precipitation. and from the upper paddy field, which comprised 13-33% of the total inflow. Although most of the nutrient outflow was attributed to plant uptake. nutrient loss by surface drainage was substantial, comprising 20% for T-N and 10% for T-P. Water and nutrient balances indicate that reduction of surface drainage from paddy rice fields is imperative for nonpoint source pollution control. The simplified computer model, PADDIMOD, was developed to simulate water and nutrient (T-N and T-P) behavior in the paddy rice field. The model predicts daily ponded water depth, surface drainage, and nutrient concentrations. It was formulated with a few equations and simplified assumptions, but its application and a model fitness test indicated that the simulation results reasonably matched the observed data. It is a simple and convenient planning model that could be used to evaluate BMPs of paddy rice fields alone or in combination with other complex watershed models. Application of the PADDIMOD to other paddy rice fields with different agricultural environments might require further calibration and validation.     

The Growing Need for Sustainable Ecological Management of Marine Communities of the Persian Gulf

The Persian Gulf is a semi-enclosed marine system surrounded by eight countries, many of which are experiencing substantial development. It is also a major center for the oil industry. The increasing array of anthropogenic disturbances may have substantial negative impacts on marine ecosystems, but this has received little attention until recently. We review the available literature on the Gulfs marine environment and detail our recent experience in the United Arab Emirates (U.A.E.) to evaluate the role of anthropogenic disturbance in this marine ecosystem. Extensive coastal development may now be the single most important anthropogenic stressor. We offer suggestions for how to build awareness of environmental risks of current practices, enhance regional capacity for coastal management, and build cooperative management of this important, shared marine system. An excellent opportunity exists for one or more of the bordering countries to initiate a bold and effective, long-term, international collaboration in environmental management for the Gulf.     

Estimating the Microbial Risk of E. coli in Reclaimed Wastewater Irrigation on Paddy Field

Microbial risk was quantified to assess human health risk as a result of exposure to E. coli in reclaimed wastewater irrigation. Monitoring data on E. coli were collected from pond water in paddy rice plots during the growing season. Five treatments were used and each was triplicated to evaluate the changes in E. coli concentrations in experiments performed in 2003 and 2004. The Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion among farmers and neighboring children. A Monte Carlo simulation (10,000 trials) was conducted to estimate the risk associated with uncertainty. In this study, risk values ranged from 10⁻⁴ to 10⁻⁸. UV-disinfected irrigation water showed a lower risk value than others, and its level was within the range of the actual paddy rice field with surface water. Agricultural activity was thought to be safer after 1–2 days, when the paddy field was irrigated with reclaimed wastewater. Also, children were found to have a greater risk of infection with E. coli. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of wastewater reuse in paddy rice culture.