长江三角洲地区大气O3和PM10的区域污染特征模拟

以TRACE-P污染源资料及上海市地方排放清单为基础,采用Models-3/CMAQ环境空气质量模型和中尺度气象模式MM5,模拟研究了2001-01和2001-07长三角近地面二次污染物O3及PM 10的浓度分布及输送状况,并以上海市国控点2001年冬、夏季各10 d的小时监测数据对模型进行了验证.验证结果显示,Models-3/CMAQ对O3和PM10的模拟结果与监测值的相关系数分别为0.77和0.52;一致性指数分别达到0.81和0.99.模型对O3小时最高浓度的估算偏低27%,标准偏差为-3.1%;对PM10小时平均浓度的估算偏低10%,标准偏差为46%.模型已具备再现和模拟长三角大气污染输送过程的能力,且误差落在可接受的范围之内.模拟结果显示,2001-07长三角区域16个主要城市中,有14个城市O3小时最大浓度超过国家二级标准,高浓度O3可覆盖苏南和浙北广大区域.2001-01泰州、扬州、南京、镇江、常州等城市受本地排放源和北部大气污染输送的影响显著,大气PM10日均浓度超过PM10国家二级标准.长三角地区环境空气质量与污染类型受大气污染传输与化学转化的影响十分明显.夏季太阳辐射较强时,南部城市排放的污染物常以二次污染物的形式影响下风向城市;太阳辐射较弱的情况下,则以一次污染物输送为主的形式影响周边地区.冬季长三角区域颗粒物污染总体水平较高,这与我国北方地区排放的颗粒物在西北风作用下向长三角输送造成的影响密切相关.长三角地区的大气污染已逐渐从局地转为区域问题.     

Response surface modeling-based source contribution analysis and VOC emission control policy assessment in a typical ozone-polluted urban Shunde, China

To develop a sound ozone (O₃) pollution control strategy, it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O₃. Using the “Shunde” city as a pilot summer case study, we apply an innovative response surface modeling (RSM) methodology based on the Community Multi-Scale Air Quality (CMAQ) modeling simulations to identify the O₃ regime and provide dynamic analysis of the precursor contributions to effectively assess the O₃ impacts of volatile organic compound (VOC) control strategy. Our results show that Shunde is a typical VOC-limited urban O₃ polluted city. The “Jiangmen” city, as the main upper wind area during July 2014, its VOCs and nitrogen oxides (NO_x) emissions make up the largest contribution (9.06%). On the contrary, the contribution from local (Shunde) emission is lowest (6.35%) among the seven neighbor regions. The local VOCs industrial source emission has the largest contribution comparing to other precursor emission sectors in Shunde. The results of dynamic source contribution analysis further show that the local NO_x control could slightly increase the ground O₃ under low (10.00%) and medium (40.00%) reduction ratios, while it could start to turn positive to decrease ground O₃ under the high NO_x abatement ratio (75.00%). The real-time assessment of O₃ impacts from VOCs control strategies in Pearl River Delta (PRD) shows that the joint regional VOCs emission control policy will effectively reduce the ground O₃ concentration in Shunde.     

广东省工业点源大气汞排放清单更新研究

基于包含工业点源位置、排放信息的2006年广东省环境统计数据和能源统计年鉴,编制了广东省2006年工业点源汞排放清单.利用该清单更新了1999年中国区大气汞排放清单中广东省行政区域内相应的点源清单数据内容.采用CMAQ-Hg模型基于同一气象、初始浓度和边界浓度输入条件对两套清单进行了更新效果评估.结果表明,使用包含工业点源位置及排放细节的bottom-up方法编制的排放清单有效提高了模拟结果的准确度.更新清单前后,本地和跨省大气汞沉降增量差异的初步研究结果说明不同形态的大气汞具备不同的干、湿沉降特征.据此提出,需要尽快开展符合我国实际的各类工业源大气汞排放因子和排放形态因子更新研究.     

Linkages between land management activities and stream water quality in a border dyke-irrigated pastoral catchment

This paper describes key linkages between land management activities and stream water quality for a 5230 ha catchment used for intensive pastoral agriculture in southern New Zealand. Due to low annual rainfall and the wide coverage of soils with low available water-holding capacities, flood irrigation of the 2400 ha of flat land within the catchment is an important feature impacting on farm business profitability and stream health. Water quality variables and nutrient and sediment yield estimates are reported for a four-year period. This monitoring shows that some improvement in farm environmental performances would generally be desirable, with stream concentrations of nutrients (N and P), sediment and faecal bacteria regularly exceeding guidelines recommended for surface waters. Field measurements, farm management surveys and farm systems modelling have identified some land management practices that appear to be key sources of many of these pollutants. Border dyke irrigation runoff has a potentially large effect on a range of water quality parameters, due to both the excessive stream flows generated by over-watering and the entrainment of P, N and faecal bacteria in this flow as it passes from land to stream. Stock access to some of the remaining un-fenced lengths of the stream was also recognised as an important land management practice that needed to be addressed if some of the key catchment values identified by stakeholders, such as maintaining a healthy trout fishery and a stream suitable for recreational use, were to be protected. Assessments of the effectiveness and cost-effectiveness of a number of potential mitigation practices identified that managements which targeted reducing irrigation runoff (e.g. by installing bunds or using appropriate watering times) and fencing and planting riparian margins showed the greatest potential to meet these key values with least cost to farm businesses. Other farm practices were also identified that incurred nil or minimal cost while also delivering small or moderate benefits to stream water quality.     

Depth and temperature of the blue marlin,Makaira nigricans,observed by acoustic telemetry

Multiplex acoustic transmitters were used to monitor the depth, swimming speeds, body temperature and water temperature preference of six blue marlin, Makaira nigricans (Lacépède), near the Hawaiian islands in July and August 1989. The blue marlin ranged in size from 60 to 220 kg and were tracked for 1 to 5 d. All of the fish moved away from the point of capture and were followed up to 253 km from the island of Hawaii. The blue marlin tracked remained in the top 200 m of the water column, spending half the time in the upper 10 m, and rarely ventured below the thermocline. In the nearsurface waters the temperature was uniformly warm (25 to 27°C). The coldest water temperature, 17°C, was encountered on the deepest descent recorded (209 m). Depth changes occurred rapidly and excursions below 10 m were usually less than 60 min in duration. Muscle temperature was similar to water temperature except for a 2°C elevation in muscle temperature observed at the beginning of tracking one individual. This initial rise in body temperature was associated with the anaerobic muscle activity during capture and is an indication of the physiological stress involved in capture.     

Aquatic leeches (Hirudinea) as bioindicators of organic chemical contaminants in freshwater ecosystems

Freshwater leeches from an industrially polluted creek were found to contain very high residues of chlorophenols, when compared with fish, tadpoles and most other benthic invertebrates. Leeches are recommended as possible bioindicators of aquatic organic contamination.     

Prenatal diagnosis of zellweger's syndrome by chorionic villus sampling-and a caveat

At 7·5 weeks gestation, two small chorionic villous biopsies were obtained from a woman at risk for Zellweger's cerebro-hepato-renal syndrome, and were separately established in culture. After 3 weeks, dihydroxyacetone phosphate acyltransferase (DHAP-AT) activity was measured in both cultures. The enzyme was markedly deficient in one cell strain and this was subsequently shown to have a male karyotype. However, the second culture had normal enzyme activity and a female karyotype. The pregnancy was terminated at 11·5 weeks gestation, and follow-up studies on fetal tissues confirmed a male fetus with markedly deficient DHAP-AT activity.     

WATER QUALITY IN THE PAWTUXET RIVER: METAL MONITORING AND GEOCHEMISTRY1

ABSTRACT: The Pawtuxet River flows from a relatively rural area through some of the more highly industrialized sections of Rhode Island. During its journey, the river receives many municipal, industrial, and ground water sources of metal constituents. The present report is the first in a two part series in which the water quality of this urban river was evaluated by a chemical monitoring study of the sources, transport mechanisms, and fate of cadmium, chromium, copper, lead, and nickel in the river. The second paper will use the chemical data to derive and calibrate a steady-state water quality model for this river. The metal concentrations In the river tended to increase from the headwaters to the mouth with river stations nearest to point source outfalls showing elevated values. In some sections of the river, levels of a few of the metals could not be explained by the point sources; and other inputs, including sediment resuspension, axe proposed to make up this apparent unbalance. The ability of a municipal secondary treatment plant to remove metals was demonstrated, and the tie-in of the effluent from a major chemical company to the plant did not cause any observable deterioration in treatment efficiency.     

Mechanisms of electron acceptor utilization: implications for simulating anaerobic biodegradation

Simulation of biodegradation reactions within a reactive transport framework requires information on mechanisms of terminal electron acceptor processes (TEAPs). In initial modeling efforts, TEAPs were approximated as occurring sequentially, with the highest energy-yielding electron acceptors (e.g. oxygen) consumed before those that yield less energy (e.g., sulfate). Within this framework in a steady state plume, sequential electron acceptor utilization would theoretically produce methane at an organic-rich source and Fe(II) further downgradient, resulting in a limited zone of Fe(II) and methane overlap. However, contaminant plumes often display much more extensive zones of overlapping Fe(II) and methane. The extensive overlap could be caused by several abiotic and biotic processes including vertical mixing of byproducts in long-screened monitoring wells, adsorption of Fe(II) onto aquifer solids, or microscale heterogeneity in Fe(III) concentrations. Alternatively, the overlap could be due to simultaneous utilization of terminal electron acceptors. Because biodegradation rates are controlled by TEAPs, evaluating the mechanisms of electron acceptor utilization is critical for improving prediction of contaminant mass losses due to biodegradation. Using BioRedox-MT3DMS, a three-dimensional, multi-species reactive transport code, we simulated the current configurations of a BTEX plume and TEAP zones at a petroleum-contaminated field site in Wisconsin. Simulation results suggest that BTEX mass loss due to biodegradation is greatest under oxygen-reducing conditions, with smaller but similar contributions to mass loss from biodegradation under Fe(III)-reducing, sulfate-reducing, and methanogenic conditions. Results of sensitivity calculations document that BTEX losses due to biodegradation are most sensitive to the age of the plume, while the shape of the BTEX plume is most sensitive to effective porosity and rate constants for biodegradation under Fe(III)-reducing and methanogenic conditions. Using this transport model, we had limited success in simulating overlap of redox products using reasonable ranges of parameters within a strictly sequential electron acceptor utilization framework. Simulation results indicate that overlap of redox products cannot be accurately simulated using the constructed model, suggesting either that Fe(III) reduction and methanogenesis are occurring simultaneously in the source area, or that heterogeneities in Fe(III) concentration and/or mineral type cause the observed overlap. Additional field, experimental, and modeling studies will be needed to address these questions.     

Trends in ambient concentrations of agrochemicals in humans and the environment of the United States

Uses of pesticides and related agrochemicals have been regulated in the United States since 1948. The United States government has supported human and environmental monitoring for pesticides and selected toxic chemicals for the past 15 yr. The initial ambient monitoring systems were designed to determine average concentrations of pesticides and related chemicals in human and environmental media on a nationwide basis and determine changes in these concentrations over time. The results of these surveys showed that almost all of the general human population and various environmental components contained low concentrations of chlorinated pesticides. As the Environmental Protection Agency (EPA) restricted many uses of the chlorinated pesticides, the organophosphorous and carbamate pesticides which replaced them were not as easily monitored by ambient surveys. Special monitoring studies had to be done more frequently to produce data on these compounds which were not as persistent or accumulative in the environment. Currently, a re-evalution has begun to determine pesticide monitoring data needs for the next 5 to 10 yr, modify existing ambient surveys, and plan needed short-term studies to efficiently meet regulatory data needs. Ambient monitoring for trends in chemical levels in humans and the environment will continue in the United States at a reduced level, and many exposure data needs will be met with use-specific monitoring studies.Presented at the International Conference on Environmental Hazards of Agrochemicals in Developing Countries, 8–12 November, 1983 in Alexandria, Egypt.