ORIGIN AND TRANSPORT OF DISSOLVED CHEMICALS IN A KARST WATERSHED,SOUTHWESTERN ILLINOIS1

ABSTRACT: An extensive base of water quality information emphasizing the effects of land use and hydrology was obtained in the karstified Fountain Creek watershed of southwestern Illinois to help resolve local water quality issues. Agrichemicals dominate the loads of most water quality constituents in the streams and shallow karstic ground water. Only calcium (Ca), magnesium (Mg), Aluminum (A1), and sulfate (SO₄) ions are predominantly derived from bedrock or soils, while agrichemicals contribute most of the sodium (Na), potassium (K), chlorine (Cl), nitrate (NO₃), fluorine (F), phosphorus (P), and atrazine. Concentrations of individual ions correlate with discharge variations in karst springs and surface streams; highly soluble ions supplied by diffuse ground water are diluted by high flows, while less soluble ions increase with flow as they are mobilized from fields to karst conduits under storm conditions. Treated wastewater containing detergent residues dominates the boron load of streams and provides important subordinate loads of several other constituents, including atrazine derived from the Mississippi River via the public water supply. Average surface water concentrations at the watershed outlet closely approximate a 92:8 mixture of karst ground water and treated wastewater, demonstrating the dominance of ground water contributions to streams. Therefore the karst aquifer and watershed streams form a single water quality system that is also affected by wastewater effluent.     

WATER QUALITY IMPROVEMENT PROGRAM EFFECTIVENESS FOR CARBONATE AQUIFERS IN GRAZED LAND WATERSHEDS1

ABSTRACT: Water quality indicators of two agriculturally impacted karst areas in southeastern West Virginia were studied to determine the water quality effects of grazing agriculture and water quality trends following initiation of water quality improvement programs. Both areas are tributaries of the Greenbrier River and received funding for best management practices under the President's Initiative for Water Quality and then under the Environmental Quality Incentives Program (EQIP). After 11 years of study there was little evidence to suggest that water quality improved in one area. Three and a half years of study in the other area showed little evidence of consistent water quality improvement under EQIP. Lack of consistent water quality improvement at the catchment scale does not imply that the voluntary programs were failures. Increased livestock numbers as a result of successful changes in forage management practices may have overridden water quality improvements achieved through best management practices. Practices that target well defined contributing areas significantly impacting aquifer water quality might be one way to improve water quality at catchment scales in karst basins. For example, a significant decrease in fecal coliform concentrations was observed in subterranean drainage from one targeted sinkhole after dairy cattle were permanently excluded from the sinkhole.     

BIOECONOMIC ANALYSIS OF SELECTED CONSERVATION PRACTICES ON SOIL EROSION AND FRESHWATER FISHERIES1

ABSTRACT: Farmers can generate environmental benefits (improved water quality and fisheries and wildlife habitat), but they may not be able to quantify them. Furthermore, farmers may reduce their incomes from managing lands to produce these positive externalities but receive little monetary compensation in return. This study simulated the relationship between agricultural practices, water quality, fish responses to suspended sediment and farm income within two small watersheds, one of a cool water stream and one of a warm water stream. Using the Agricultural Drainage and Pesticide Transport (ADAPT) model, this study related best management practices (BMPs) to calculated instream suspended sediment concentrations by estimating sediment delivery, runoff, base flow, and streambank erosion to quantify the effects of suspended sediment exposure on fish communities. By implementing selected BMPs in each watershed, annual net farm income declined $18,000 to $28,000 (1 to 3 percent) from previous levels. “Lethal” fish events from suspended sediments in the cool water watershed decreased by 60 percent as conservation tillage and riparian buffers increased. Despite reducing suspended sediments by 25 percent, BMPs in the warm water watershed did not reduce the negative response of the fisheries. Differences in responses (physical and biological) between watersheds highlight potential gains in economic efficiency by targeting BMPs or by offering performance based “green payments.”     

DRY AND WET WEATHER FLOW NUTRIENT LOADS FROM A LOS ANGELES WATERSHED1

Effective watershed management requires an accurate assessment of the pollutant loads from the associated point and nonpoint sources. The importance of wet weather flow (WWF) pollutant loads is well known, but in semi‐arid regions where urbanization is significant the pollutant load in dry weather flow (DWF) may also be important. This research compares the relative contributions of potential contaminants discharged in DWF and WWF from the Ballona Creek Watershed in Los Angeles, California. Models to predict DWF and WWF loads of total suspended solids, biochemical oxygen demand, nitrate‐nitrogen, nitrite‐nitrogen, ammonia‐nitrogen, total Kjeldahl nitrogen, and total phosphorus from the Ballona Creek Watershed for six water years dating from 1991 to 1996 were developed. The contaminants studied were selected based on data availability and their potential importance in the degradation of Ballona Creek and Santa Monica Bay beneficial uses. Wet weather flow was found to contribute approximately 75 percent to 90 percent of the total annual flow volume discharged by the Ballona Creek Watershed. Pollutant loads are also predominantly due to WWF, but during the dry season, DWF is a more significant contributor. Wet weather flow accounts for 67 to 98 percent of the annual load of the constituents studied. During the dry season, however, the portion attributable to DWF increases to greater than 40 percent for all constituents except biochemical oxygen demand and total suspended solids. When individual catchments within the watershed are considered, the DWF pollutant load from the largest catchment is similar to the WWF pollutant load in two other major catchments. This research indicates WWF is the most significant source of nonpoint source pollution load on an annual basis, but management of the effects of the nonpoint source pollutant load should consider the seasonal importance of DWF.     

MODELING THE DISTRIBUTION OF DIFFUSE NITROGEN SOURCES AND SINKS IN THE NEUSE RIVER BASIN OF NORTH CAROLINA,USA1

This study quantified nonpoint source nitrogen (NPS‐N) sources and sinks across the 14,582 km² Neuse River Basin (NRB) located in North Carolina, to provide tabular data summaries and graphic overlay products to support the development of management approaches to best achieve established N reduction goals. First, a remote sensor derived, land cover classification was performed to support modeling needs. Modeling efforts included the development of a mass balance model to quantify potential N sources and sinks, followed by a precipitation event driven hydrologic model to effectively transport excess N across the landscape to individual stream reaches to support subsequent labeling of transported N values corresponding to source origin. Results indicated that agricultural land contributed 55 percent of the total annual NPS‐N loadings, followed by forested land at 23 percent (background), and urban areas at 21 percent. Average annual N source contributions were quantified for agricultural (1.4 kg/ha), urban (1.2 kg/ha), and forested cover types (0.5 kg/ha). Nonpoint source‐N contributions were greatest during the winter (40 percent), followed by spring (32 percent), summer (28 percent), and fall (0.3 percent). Seasonal total N loadings shifted from urban dominated and forest dominated sources during the winter, to agricultural sources in the spring and summer. A quantitative assessment of the significant NRB land use activities indicated that high (greater than 70 percent impervious) and medium (greater than 35 percent impervious) density urban development were the greatest contributors of NPS‐N on a unit area basis (1.9 and 1.6 kg/ha/yr, respectively), followed by row crops and pasture/hay cover types (1.4 kg/ha/yr).     

PREDICTING FECAL COLIFORM BACTERIA LEVELS IN THE CHARLES RIVER,MASSACHUSETTS, USA1

In Massachusetts, the Charles River Watershed Association conducts a regular water quality monitoring and public notification program in the Charles River Basin during the recreational season to inform users of the river's health. This program has relied on laboratory analyses of river samples for fecal coliform bacteria levels, however, results are not available until at least 24 hours after sampling. To avoid the need for laboratory analyses, ordinary least squares (OLS) and logistic regression models were developed to predict fecal coliform bacteria concentrations and the probabilities of exceeding the Massachusetts secondary contact recreation standard for bacteria based on meteorological conditions and streamflow. The OLS models resulted in adjusted R²s ranging from 50 to 60 percent. An uncertainty analysis reveals that of the total variability of fecal coliform bacteria concentrations, 45 percent is explained by the OLS regression model, 15 percent is explained by both measurement and space sampling error, and 40 percent is explained by time sampling error. Higher accuracy in future bacteria forecasting models would likely result from reductions in laboratory measurement errors and improved sampling designs.     

南水北调中线陕西水源区污染源排放时空变化特征

基于2008—2012年污染源环境统计数据,采用Spearman秩相关系数法等分析南水北调中线陕西水源区污废水及污染物年排放总量变化趋势,借助ArcGIS空间分析功能表征水源区污染源排放的空间分布特征。结果表明:2008—2012年水源区污废水和NH_3-N年排放总量呈显著上升趋势,COD、As、Pb、Cd、Cr和Hg年排放总量呈抛物线型变化,总体上COD、Pb、Cd年排放总量增加,As、Cr和Hg年排放总量降低。水源区污废水及污染物排放量空间差异明显,污废水、COD和NH_3-N排放涉及流域所有区县,其排放量从干流到流域边缘呈现较明显的梯度变化,即位于流域中心或地级市行政中心的区县排放量明显高于位于流域边缘的区县;As、Pb、Cd、Cr和Hg排放量呈现明显的区域分布,主要分布在勉县等8个区县。     

Limits of ecodesign: the case for open source product development

Abstract

In pursuit of coping mechanisms for the challenges of sustainable manufacturing, systematic methods have been developed to allow engineers to improve the ratio between products’ utility and environmental impact. These necessary efforts remain however limited if the surrounding production and consumption practices are not called into question at the same time. This article introduces open source product development as a potential approach for unlocking the limits of existing sustainable product design practices and to lead towards alternative and eco-efficient production and consumption practices termed as participative production. First, it discusses the potential advantages of this emerging practice in terms of environmental sustainability. Second, it provides a screened qualitative environmental analysis of 18 exemplary open source hardware products. Specific sustainable design principles implemented by these products are highlighted and discussed in order to identify challenges for further common research in the field of open source and sustainable product development.     

黄、渤海滨海带大气颗粒物时空分布与来源特征

PM10作为大气污染物监测的主要指标之一,探究大气PM10浓度对大气环境质量和人体健康评价具有重要意义。黄、渤海滨海带包括京、津和辽、冀、鲁、苏等工、农业大省,区域大气PM10污染的时空分布和来源特征具有复杂性和典型性。在锦州、北京、天津、烟台、青岛、连云港和盐城7个城市布设10个采样点,含7个城市点和3个农村点,开展为期一年的大气颗粒物的采样;同时,于冬季1月和夏季7月在锦州、天津和烟台进行合计60 d的加密采样,藉以确定研究区域大气PM10的时空分布和来源特征。结果表明,黄、渤海滨海带大气年均PM10总浓度为(129’18)"g·m~(-3),单月最低值出现在2015年7月盐城农村样点15"g·m~(-3),最高值为2015年3月北京城市点307"g·m~(-3)。盐城大气PM10浓度(城市点(85’27)"g·m~(-3)和农村点(66’35)"g·m~(-3))显著低于其他样点大气PM10浓度。渤海滨海带中西部的京(140’68"g·m~(-3))、津(169’60"g·m~(-3))两市大气PM10年均浓度显著高于东部的锦州(125’41"g·m~(-3))和烟台(109’31"g·m~(-3));而且黄海滨海带大气PM10年均浓度(114"g·m~(-3))显著低于渤海滨海带年均浓度(136"g·m~(-3)),总体上表现出西高东低、北高南低的特征。黄、渤海滨海带城市点和农村点年均浓度分别为(129’18)"g·m~(-3)和(112’30)"g·m~(-3);农村点春冬季大气PM10浓度和城市点浓度相当,无显著差异,夏秋季大气PM10浓度略低于城市浓度,表明农村地区大气颗粒物污染情况也较为严重,需受到关注。区域内PM10浓度季节变化整体表现为春冬高、夏秋低。利用多元回归分析初步判断黄、渤海滨海带PM10属于复合来源,大气PM10浓度约30%的变化与降水、人均能耗和沙尘天气相关。黄、渤海滨海带大气PM10浓度的昼夜变化不大,大气PM10浓度与气温呈现正相关,与风速和降水呈现负相关,表现为受各种气象因素综合作用的影响。     

太原市土壤六六六和滴滴涕的暴露格局及健康风险

为研究六六六(HCHs)和滴滴涕(DDTs)在太原市不同功能区土壤中的暴露格局、来源以及对周围人群的健康风险,在太原市化工区、灌区、矿区、生态区周边荒地土壤中进行采样,分析测定了土壤中HCHs和DDTs含量,根据太原市人群实际情况的暴露参数和USEPA的部分参数,对土壤HCHs和DDTs的健康风险进行评价。结果表明:1)太原市表层土壤中HCHs的平均含量大小依次为化工区>灌区>矿区>生态区;DDTs平均含量的大小依次为化工区>灌区>矿区>生态区,仅6%的HCHs和3%的DDTs和的平均残留水平均高于我国土壤质量标准一级标准,但均不超过二级标准值;2)土壤中HCHs残留主要源于历史上林丹的使用,DDTs残留则来源于历史和新污染源的共同影响;3)太原市表层土壤HCHs和DDTs致癌风险大小为化工园区>矿区>灌区>生态区。非致癌风险大小为化工区>矿区>灌区>生态区。3种暴露途径的在不同功能区的健康风险贡献率大小均为经口摄入>呼吸吸入>皮肤接触;综合来看太原市表层土壤中的HCHs和DDTs并未对人类造成非致癌风险,但有一定的致癌风险。本文的研究结果可为太原市土壤质量评价和环境污染防治提供科学指导,并对太原市人群的健康风险防治提供依据。