Ambient Water Quality Standards Research Articles

Impacts of Organic and Non-organic Paddy Farming Practices on Surface Water Quality in Selected Areas

Paddy (Oryza sativa L.) cultivation plays major role in Sri Lanka. Mainly Organic and Non-organic paddy farming methods are conducted. Organic paddy farming method only used organic fertilizers and non-organic paddy farming method used chemical fertilizers which are Urea, Triple Super Phosphates. Therefore, farming practices can be affected to the surface water quality creating various health hazards. The study was conducted from November 2021 to February 2022 (Maha season) to assess the impact of organic and non-organic paddy farming practices on surface water quality in Wallewala, Homagama, and Kottawa paddy agricultural lands by analyzing pH, EC, TDS, DO, BOD, COD, total hardness, nitrate, nitrite, phosphate, sulfate, chloride, potassium, zinc, and chromium. Wallewala is newly created environment sensitive agricultural land in less human influence. Both organic and non-organic paddy lands are in that area. Kottawa paddy lands are cultivated only chemical fertilizers and the Homagama paddy lands are cultivated by organic fertilizers. Randomly, six and nine surface water samples were collected from paddy irrigated systems in Wallewala area represent to organic and non-organic paddy lands respectively. Randomly, five and six surface water samples were collected from paddy irrigated systems in Homagama Organic, and Kottawa non-organic paddy lands respectively. The water from both paddy systems, min pH (5.25±0.04), max EC (315±1.00 μScm-1 ), min DO (6.13±0.06 mgL-1), max BOD5 (2.82±0.06 mgL-1), max sulfate (205.76 ppm), max chloride (45.91 ppm), max K (5.63 ppm), and max Zn (0.12 ppm) were found, while the study revealed that all the water quality parameters were not exceeded the reported ambient water quality standards for inland waters in Sri Lanka for irrigation purposes. Further EC, TDS, COD, total hardness, sulfates, chloride, potassium, and zinc were greater in non-organic paddy lands in both Wallewala and Kottawa areas. According to the obtained data, there was no water pollution from the paddy cultivation in respective areas. But these results indicate that water quality parameters vary with the utilized fertilizers. 
 Keywords: Paddy cultivation, Water quality, Organic paddy farming, Non-organic

Health risk assessment and development of human health ambient water quality criteria for PCBs in Taihu Basin, China

Polychlorinated biphenyls (PCBs) are a class of typical persistent organic pollutants (POPs) with carcinogenicity and extensively found in diverse environmental mediums. The Taihu Basin is one of the most economically developed regions in China, and it has also caused a lot of historical legacy and unconscious emissions of PCBs, posing a threat to the health of people in the region. This study counted the concentrations of PCBs in five environmental media (water, soil, air, dust, and food) in the Taihu Basin from 2000 to 2020 and used Monte Carlo simulation to simulate the multi-channel exposure of PCBs in people of different ages (children, teenagers, and adults), and evaluated their noncarcinogenic and carcinogenic health risks. Finally, the human health ambient water quality standards (AWQC) for PCBs were obtained using regional exposure parameters and bioaccumulation factors. The results showed that the pollution of PCBs in the Taihu Basin was relatively serious in China. The concentration of PCBs in dust is higher than other environmental media. And exposure to water and food is the main exposure pathway for PCBs in the population of the region. Besides, PCBs pose no noncarcinogenic risk to people in this region, but their carcinogenic risk to residents exceeds the safety threshold. Among the three population groups, adults have the highest risk of cancer, and prevention measures need to be taken by controlling the intake of related foods and the concentration of PCBs in water. The following human health AWQC values of the PCBs in Taihu Basin is 3.2 × 10−9 mg/L.

Analysis of Ningxia Hui Autonomous District’s Gray Water Footprint from the Perspective of Water Sustainability

Gray water footprint (GWF) is an effective method to evaluate the degree of water pollution and water quality. It is the amount of freshwater needed to dilute water pollutants to meet ambient water quality standards. Accounting and analyzing the GWF will be significant for promoting an improved water environment and sustainable water ecology in Ningxia Autonomous District. We accounted for the GWF of all cities in Ningxia from 2012 to 2020 and evaluated its spatial-temporal variations by the GWF accounting method proposed by Hoekstra. Then, the Logarithmic Mean Divisia Index (LMDI) method was applied to investigate the contributions of four driving factors: the population scale effect, economic development effect, technological effect, and industrial structure effect. And then, the changes in the GWF in the Ningxia region were analyzed. The results showed that the GWF in the Ningxia region changed from 79.21 × 108 to 29.09 × 108 m3/yr during 2012–2020, making a significant decreasing trend. Among all cities, Wuzhong City contributes the most in terms of the GWF. More specifically, economic development and technology structure are the positive and negative drivers of the GWF, respectively. The water pollution levels in Ningxia (0.49–1.3) indicated that the waste assimilation capacity has fallen short of taking up the pollutant load, which had an unfavorable impact on the groundwater according to actual water quality data. NO3-N and NH3-N are detected in the groundwater throughout the Ningxia region, with the highest NH3-N content in the groundwater in Yinchuan, which almost exceeded the groundwater quality standard of category III. Above all, this study reflected the current water pollution situation better by combining the GWF with actual water quality data in Ningxia. The finding of this study is valuable for addressing water quality threats and developing sustainable development.

Evaluation of locally-available agricultural and industrial waste materials as effective carriers for bacterial inocula in freshwater bioremediation

The pollution of freshwater is a pressing global environmental concern, necessitating effective management strategies for polluted aquatic environments. Bioremediation has emerged as a highly promising environmentally friendly approach. However, the selection of suitable candidates capable of effectively degrading or removing pollutants remains a challenging task. The introduction of live candidates, particularly bacteria, into natural environments also poses its own set of difficulties. To address these challenges, immobilizing bacteria within carrier materials has emerged as a leading option. In this study, we meticulously assessed the suitability of four locally-available and low-cost agricultural and industrial waste materials as carriers to transport bacteria into water bodies. The selection criteria encompassed bacteria immobilization capacity, viability, and the resulting water quality after treatment. In order to facilitate comparison, the widely-used sodium alginate was included as a benchmark, and Escherichia coli was employed as the model bacterial inoculum. Our findings revealed that alkaline pre-treatment of corn husk, rice husk, rice straw, and sugarcane bagasse significantly enhanced the bacteria immobilization capacity of these materials. Notably, the viability of bacteria in carrier materials, including sodium alginate, exhibited remarkable resilience, with a count of 107 CFU/g material even after 49 days of storage at room temperature. Moreover, upon determining the quality parameters of the receiving water, the introduction of rice husk and sodium alginate materials demonstrated no significant adverse impact. The quality parameters were well within the acceptable range defined by the World Health Organization standards for drinking water and the Sri Lankan ambient water quality standards for various purposes. Based on the overall performance evaluation, we advocate for the application of rice husk and sodium alginate as superior carriers for delivering bacterial inocula to aquatic environments, particularly in polluted water bodies targeted for bioremediation efforts. Nonetheless, we recommend the collection of carrier materials only after the establishment of bio inoculum in the receiving water, as a precautionary measure to minimize any potential impact on the chemical oxygen demand of the water.

Application of water pollution and heavy metal pollution indices to evaluate the water quality in St. Sebastian Canal, Colombo, Sri Lanka

Anthropogenic pollution plays an important role in deteriorating the water quality of canals worldwide, especially in developing countries like Sri Lanka. The St. Sebastian Canal is one of the main canals in Sri Lanka, which runs through Colombo city that collects massive quantities of domestic, municipal, and industrial waste products. The aim of the present study is to develop water pollution and heavy metal pollution indices to assess the water pollution status of the St. Sebastian canal, Colombo by comparing water quality parameters with ambient water quality standards for aquatic life in Sri Lanka. Water samples were analyzed for physical and chemical parameters and heavy metals. Ultimately, Water Pollution Index (WPI) and Heavy Metal Pollution Index (HPI) were developed for several sites along the canal. WPI ranged from 0.64 to 1.93 with a mean value of 1.12, indicating water of St. Sebastian canal is highly polluted. The mean value of HPI was found to be 50, which is higher than the critical HPI value of 30, thus indicating that water of the canal is critically polluted with heavy metals. Further, sites 1, 5, 6, 7, 8 and 9 and sites 1, 4, 5, 6, 7, 8 and 9 were found to be highly polluted as per the WPI and HPI, respectively. This shows the importance of having both WPI and HPI to assess the level of water pollution as site 4 is being categorized as a highly polluted site by HPI and as a good water quality site by WPI. Therefore, the site-specific assessment of water pollution by WPI and HPI will help the relevant authorities to implement remediation methods with respective to the critical pollutants in a particular location, to identify the polluters and to take measures to prevent the discharges to the water body from different sources.

Evaluation of hydrochemistry and identification of pollution hotspots of little Akaki river using integrated water quality index and GIS

Despite unwavering effort of the government, urban river pollution in Ethiopia has remained a worrisome phenomenon now a days. This research is conducted with a prime aim of assessing and evaluating the water quality status and identifying and mapping of the pollution hotspots in the Little Akaki River (LAR), Ethiopia by integrating the water quality index (CCME-WQI) and Geographic Information System (GIS). Accordingly, water quality samples were collected from 22 monitoring stations. The water samples were collected and analyzed for physico-chemical and heavy metal constituents using the American Public Health Association (APHA) standard methods. Most of the physico-chemical constituents analyzed have surpassed the standard guideline value of the country and World Health Organization (WHO). In addition, most of the middle (S3-S10) segments of the river is heavily polluted than the downstream segment (S11-S14) and upstream segments. Similarly, the heavy metals concentrations in the LAR have decreasing trend with Mn>Zn>Pb>Cu>Cd. On the other hand, the overall CCME-WQI modeling output ranged from 18.9 – 36.2. Accordingly, the finding of the study reveals that most water quality parameters were beyond ambient surface water quality standards and the CCME-WQI categorizes all the monitoring stations under poor water quality state. Besides, the spatial distribution of pollution in LAR shows intense deterioration at the middle segment of the river and needs a proper strategic management plan in the catchment and immediate protection and restoration of the natural ecology of the LAR. It is recommended to integrate river water pollution management and maintain ecologically to achieve healthy urban development.

A multi-pronged approach to source attribution and apportionment of heavy metals in urban rivers.

Heavy metal (HM) contamination of water bodies is caused by both first generation (industries) and second generation (distributed sources, domestic sewage, sediments) sources. We applied a multi-pronged approach to quantify the contribution of first and second generation sources to the HM load in a stream located in an industrialised catchment. We found that, despite strict regulation, first generation sources contributed significantly to the HM load (60%-80%), showing the ineffectiveness of current regulation. Domestic sewage contributed significantly to Cu, Ni, and Mn load (15%-20%). The contribution of distributed sources and sediments to HM load is insignificant. In a 24-hour cycle, HM concentrations frequently exceeded FAO's irrigation water quality standards, with the highest concentrations observed at night. Empirically, the study highlights the continued plight of urban streams in rapidly industrialising centers and the failure to regulate first-generation sources. Methodologically, it demonstrates the importance of temporally intensive measurement of contaminant concentration and load. Policy implications include the need for ambient water quality standards, inclusion of HMs in such standards, load-based regulation, and a problem-oriented monitoring and enforcement approach.

Assessment of Surface Water Quality of an Urban Wetland: Thalangama Wetland, Colombo, Sri Lanka

Thalangama wetland is situated within the Kelani river basin, Colombo District, Sri Lanka. It is one of the most attractive landscapes in Colombo that provides a wide range of ecological, social and economic functions. Wetland water supports aquatic life and is being prominently used for agriculture and bathing and contact recreational activities without knowing if the water quality is appropriate for such uses. This study was therefore conducted to assess the surface water quality of Thalangama wetland using key-physicochemical parameters and to examine the suitability of wetland waters for bathing and contact recreational water, aquatic life, irrigation and other agricultural activities. A total of 10 water quality parameters covering temperature, pH, salinity, TDS, EC, DO, BOD, COD, nitrate, and total phosphate were measured at eight sampling sites of the wetland. The study was conducted in August 2020. The spatial variation of water quality parameters was assessed using one-way ANOVA followed by Tukey’s pairwise comparison. Results were compared with ambient water quality standards of Sri Lanka. The study revealed that the surface water quality parameters including temperature, EC, TDS, DO, BOD, COD, nitrate and total phosphate show a significant spatial variation among the sampling sites. Surface water pH and BOD at all the sampling sites were within the ambient water quality standards for water suitable for bathing and contact recreational water and water suitable for aquatic life, irrigation and agricultural activities. EC at all the sampling sites were within the limits of water suitable for irrigation and agricultural activities. Nitrate and total phosphate concentrations at all the sampling sites were within the limits of water suitable as bathing and contact recreational water and water suitable for aquatic life. DO at six out of eight sampling sites were within the limits of water suitable as bathing and contact recreational waters and water suitable for aquatic life, irrigation and agricultural activities. COD at all the sampling sites were not within the limits of water suitable as bathing and contact recreational water and water suitable for aquatic life. The study identifies agricultural practices, livestock rearing, construction activities and urban discharges as major anthropogenic influences that degrade the surface water quality of the wetland. Hence, the study determines the necessity for effective management of the surface water of Thalangama wetland to prevent pollution and to ensure the water quality of the wetland is within the recommended standards.
 Keywords: Urban wetlands, Surface water quality, Spatial variation, Physicochemical parameters, Ambient water quality standards

Development of an Irrigation Water Quality Database to Identify Water Resources and Assess Microbiological Risks During the Production of Fresh Fruits and Vegetables

An Irrigation Water Quality Database was developed to help assess the microbiological quality of irrigation water used in fruit and vegetable production in 15 counties in New York (NY) State. Water samples from Tennessee (TN) were also included in the database. Four water quality parameters, quantified generic Escherichia coli, specific conductance, pH, and turbidity, were tested. Ground, reservoir, and running water were sampled over 2 years (2009 and 2010), covering three seasons each year (spring, summer, and fall). TN data are for all three seasons in 2010 only. Overall in NY (254 total samples), ground water had a geometric mean of 1 most probable number (MPN)/100 ml, reservoir water had a geometric mean of 8 MPN/100 ml, and running water had a geometric mean of 52 MPN/100 ml. Overall in TN (63 total samples), ground water had a geometric mean of 1 colony forming unit (CFU)/100 ml, reservoir water had a geometric mean of 5 CFU/100 ml, and running water had a geometric mean of 38 CFU/100 ml. These values are all below the 126 MPN/100 ml United States Environmental Protection Agency's Ambient Water Quality Standards (AWQS) standard for fresh water. The presence of E. coli had very weak but sometimes statistically signficiant correlatation with water specific conductance, pH, and turbidity, depending on the water source but the r-squared effect was not strong enough to make the other measurements a substitute for testing specifically for E. coli in water.

Stream Salamanders are Relatively Tolerant of Salty Streams.

The application of road salt as a deicing agent is common, but investigations of potential negative effects of salt runoff on stream salamanders have been limited. Additionally, modern stormwater management practices should influence the delivery of salt ions to streams. We used data loggers in streams draining watersheds with and without stormwater management ponds and acute 96-h LC50 tests to investigate exposure of, and road salt toxicity among, two widespread salamanders in the Eastern USA, northern dusky salamanders (Desmognathus fuscus) and northern two-lined salamanders (Eurycea bislineata). In streams below stormwater ponds, base levels of conductivity were elevated throughout the year and elevated Cl- levels led to more frequent acute and chronic exceedances of U.S. Environmental Protection Agency ambient water quality criteria for Cl- when compared to streams draining watersheds with no stormwater management ponds. However, five of the six streams studied had exceedance frequencies suggesting Cl- associated with road salt application represented a persistent threat to aquatic life. Larval stream salamanders were relatively tolerant of salt, not exhibiting any lethal effects over a 96-h period until chloride levels exceeded 5000mg/L for both species, and concentrations in streams rarely exceeded these levels and only for very short periods of time. Our results suggest road salts are not having acute lethal effects on salamanders in the streams we studied, but exceedance of U.S. Environmental Protection Agency ambient water quality standards for Cl- suggest the potential for sublethal and indirect effects of Cl- on salamander populations that require further study.

Assessment of Environmental Water Security of an Asian Deltaic Megacity and Its Peri-Urban Wetland Areas

Achieving urban water security requires sustaining the trade-offs between the exploitation of water/environmental resources and ecosystem services. This achievement not only reduces the pollution and contamination in the environment, level of water stress, but also secures good ambient water quality and future for people’s well-being and livelihoods. Changes in land use and land cover and growth of impervious structures can immediately generate severe ecological and social issues and increase the level of natural or manmade risks, affecting the condition of ecosystem services within and in the vicinity of an urban region. As a result of these transformations and further exploitation, due to the growing anthropogenic pressure, surface water and groundwater quality can be deteriorated compared to ambient water quality standards (for both chemical and biological pollutants). Based on land use and land cover (LULC) data retrieved from remote sensing interpretation, we computed the changes of the ecosystem service values (ESV) associated with the LULC dynamics, water quality and, finally, urban water security during the pre- and post-monsoon periods of 2009, 2014 and 2019 in Kolkata, an Asian deltaic megacity, and its peri-urban wetlands named East Kolkata Wetlands (EKW). The area under wetlands reduced comprehensively in 2009–2019 due to the conversion of wetlands into various other classes such as urban settlement, etc. The quality of surface water bodies (such as rivers, lakes, canals and inland wetlands) deteriorated. The groundwater quality is still under control, but the presence of arsenic, manganese and other metals are a clear indication of urban expansion and related activities in the area. As a result, there was a change in the ESV during this timeframe. In the pre-monsoon period, there was an increase in total ESV from US$53.14 million in 2009 to US$53.36 million and US$59.01 million in 2014 and 2019, respectively. In the post-monsoon period, the ESV decreased from US$67.42 million in 2009 to US$64.13 and US$61.89 million in 2014 and 2019, respectively. These changes can be attributed to the peri-urban wetlands and the benefits or services arising out of them that contribute more than 50% of the total ESV. This study found that the area under wetlands has reduced comprehensively in the past 10 years due to the conversion of wetlands for various other uses such as urban expansion of the Kolkata City, but still, this peri-urban wetland supports the urban water security by providing sufficient ecosystem services. In conclusion, the transformation in extent of the water-related ecosystem is a crucial indicator of urban water security, which also measures the quantity of water contained in various water-related ecosystems. Quantitative analysis of the LULC change, hence, is important for studying the corresponding impact on the ecosystem service value (ESV) and water quality that helps in decision-making in securing urban water future and ecosystem conservation.

Precautionary buffers and stochastic dependence in environmental policy

Against a backdrop of rising uncertainty driven by a warming climate, environmental policy has become increasingly reliant on precautionary buffers to safeguard public health, prevent irreversible environmental damages and limit the likelihood of exceeding critical thresholds. These probabilistic constraints are usually implemented under a separability assumption even though outcomes are often dependent. Examples include ambient air pollution and water quality standards, phytosanitary trade measures, and reference points in fisheries management. In this paper, we characterize how stochastic dependence among environmental variables influences environmental policy when the governing regulatory systems use probabilistic precautionary buffers. Our approach builds on Sklar's theorem and the copula representation of multivariate distributions and uses stochastic dependence orderings to compare policy design for different dependence structures including correlated, independent and separable risks. Dependence typically renders policy based on separability suboptimal and we characterize how policy should be adjusted in the presence of correlated risks. We illustrate the theory using fisheries management in the Gulf of Maine, one of the fastest-warming ocean ecosystems on the planet. In its multispecies fishery, even a mild positive correlation between stocks can result in a substantial reduction in effort limits if overfishing is to be avoided.

Development of ambient marine standards using long-term data: An example from Abu Dhabi

Abu Dhabi, the capital of the United Arab Emirates, has a coastline that occupies 76% of the country’s Arabian Gulf coastline. The pressures accompanying the economic development that the country is undergoing ultimately affected the marine ecosystem including water and sediment quality. In order to protect the marine ecosystem and public health, the Environment Agency- Abu Dhabi developed ambient marine water and sediment quality standards using the long-term data collected along the coast of Abu Dhabi. Along with the data collected on 39 marine water quality and sediment parameters (hydrography, nutrients, and heavy metals), a review of best practices from jurisdictions whose approach was scientifically based and whose physical conditions were as similar as possible to those found in Abu Dhabi were used for the establishment of marine water and sediment quality limits. These promulgated ambient limits were then used to develop the marine water and sediment regulation that establish two uses of marine waters (protected and general) and an anti-degradation policy. In addition, the ambient water and sediment limits provide a bench mark to both assess trends that may indicate stress to marine flora and fauna and support the work of environmental permitting and enforcement.

Cooperative Federalism and the Clean Water Act: Implementation in Minnesota and North Dakota

Abstract The primary policy instrument for promoting and regulating surface water quality in the United States is the Clean Water Act. Under a system of cooperative federalism, the implementation of this policy involves state and federal agencies. This article will review current controversies over the Clean Water Act, including the definition of the “waters of the USA,” and the use of narrative ambient water quality standards. The case studies of North Dakota and Minnesota are enlightening because they have distinct economies with different water management priorities. Minnesota demonstrates that local demands for water quality can lead to extra effort and innovation. North Dakota continues to be more concerned with water quantity issues and flood mitigation. Despite states’ efforts to manage water quality to suit their own needs, interstate water quality concerns, especially excess nutrients, remain a concern.

Acute and Chronic Toxicity of Cobalt to Freshwater Organisms: Using a Species Sensitivity Distribution Approach to Establish International Water Quality Standards

Water quality standards for cobalt (Co) have not been developed for the European Union or United States. The objective of the present study was to produce freshwater Co toxicity data that could be used by both the European Union and the United States to develop appropriate regulatory standards (i.e., environmental quality standards or predicted-no-effect concentrations in Europe and ambient water quality criteria or state water quality standards in the United States). Eleven species, including algae, an aquatic plant, and several invertebrate and fish species, were used in the performance of acute and chronic Co toxicity tests. Acute median lethal or median effective concentration (LC50 or EC50) values ranged from 90.1 µg Co/L for duckweed (Lemna minor) to 157 000 µg Co/L for midges (Chironomus tentans). Chronic 10% effect concentration (EC10) values ranged from 4.9 µg Co/L for duckweed to 2170 µg Co/L for rainbow trout (Oncorhynchus mykiss). Chronic 20% effect concentration (EC20) values ranged from 11.1 µg Co/L for water flea (Ceriodaphnia dubia) to 2495 µg Co/L for O. mykiss. Results indicated that invertebrate and algae/plant species are more sensitive to chronic Co exposures than fish. Acute-to-chronic ratios (derived as acute LC50s divided by chronic EC20s) were lowest for juvenile O. mykiss (0.6) and highest for the snail Lymnaea stagnalis (2670). Following the European-based approach and using EC10 values, species sensitivity distributions (SSDs) were developed and a median hazardous concentration for 5% of the organisms of 1.80 µg Co/L was derived. Chronic EC20 values were used, also in an SSD approach, to derive a US Environmental Protection Agency-style final chronic value of 7.13 µg Co/L. Environ Toxicol Chem 2020;39:799-811. © 2020 SETAC.

福建省灰水足迹时空变化及驱动因素

PDF HTML阅读 XML下载 导出引用 引用提醒 福建省灰水足迹时空变化及驱动因素 DOI: 10.5846/stxb201910292274 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 福建省公益类重点项目（2019R1002-7） Spatio-temporal variations and driving factors of grey water footprint in Fujian Province Author: Affiliation: Fund Project: Key Project of Fujian Province Public Institutions 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:灰水足迹是稀释水污染物至达标需要的淡水体积，是评价水污染程度与水环境质量的重要方法，对灰水足迹进行核算与分析，可以促进福建省提高水环境质量，构建可持续的水生态环境。借鉴Hoekstra等提出的灰水足迹核算方法，对福建省及各地市2001-2017年的灰水足迹进行核算，对其时空变化特征进行评价并使用对数平均迪式指数分解法（Logarithmic Mean Divisia Index Method，LMDI）模型对灰水足迹变动的驱动因素进行分解。结果表明：a）总氮是决定灰水足迹总量的主要污染物，非点源污染是灰水足迹的最主要来源但占比由68.25%降至63.35%；b）福建省灰水足迹总量降低了9.58%，且各项指标都呈下降趋势，在空间上，灰水足迹总量及剩余灰水足迹东南多西北少，人均灰水足迹及灰水足迹强度东少西多；c）福建省灰水足迹变动的驱动因素中，经济因素是最大正向驱动因素，产生2932.96亿m3的贡献量，技术因素是最大负向驱动因素，产生-2630.31亿m3的贡献量。最后，针对福建省水污染问题提出建议：a）开展非点源污染防治专项；b）加快速度提高城镇生活污水处理水平；c）优化产业结构，提高灰水足迹效率；d）切实落实生态补偿制度，调动各市水环境保护积极性；e）加强环境监管力度，加大技术投入。 Abstract:The grey water footprint is the amount of freshwater required to assimilate the load of water pollutants in order to meet ambient water quality standards and it is an effective method to evaluate the degree of water pollution and the quality of water. By accounting and analyzing of grey water footprint, it will contribute to improve the water environment and promote sustainable water ecology in Fujian province. We accounted the grey water footprint of Fujian province and 9 local cities from 2001 to 2017 by reference to the grey water footprint accounting method proposed by Hoekstra et al, analyzed the spatio-temporal variations, and applied the Logarithmic Mean Divisia Index Method (LMDI) to investigate the contributions of five driving factors. The results showed as follows. a) The total nitrogen (TN) was considered as the major pollutant of total grey water footprint of Fujian province. Non-point pollution was the major resource of grey water footprint but its proportion have decreased from 68.25% to 63.35%. b) The total grey water footprint decreased by 9.58%, and there was a downtrend of all other indicators. The total grey water footprint and the remaining grey water footprint amount was more in the southeast than that in the northwest, while the west amount was more than that in the east for the per capita grey water footprint and grey water footprint intensity. c) Among the driving factors of Fujian's grey water footprint, the economic factor was dominantly positive, making a contribution of 293.296 billion m3, while the technical factor was the most negative one, making -263.031 billion m3 contribution. Therefore, we suggest that:a) launching a project to prevent and control non-point pollution; b) Speeding up the enhancement of urban sewage treatment technique; c) Optimizing the industrial structure and improving the efficiency of grey water footprint; d) Implying a mechanism for ecological compensation, fully mobilizing the initiative of all quarters to protect water environment; and e) Strengthening the supervision of environment and taking efforts to achieve the integration of technological advance and economic rationality. 参考文献 相似文献 引证文献

Improved gray water footprint calculation method based on a mass-balance model and on fuzzy synthetic evaluation

Gray Water Footprint (GWF), defined as the volume of fresh water required to assimilate the load of pollutants discharged into water based on natural background concentrations and existing ambient water quality standards, has been widely used as indicator in water quality management. In the present form, GWF values are mainly influenced by concentration value of the highest concentrated pollutant. Thus, the co-presence of other critical compounds is almost disregarded. GWF values, assessed against a set of quality thresholds (i.e.: different water quality classes set by regulations), support the classification of water bodies in different quality categories. However, since norms refer to many pollutants, an intrinsic fuzziness is embedded in the correct classification of water bodies affected by wastewater discharges. To mitigate these concerns, in this study, an improved GWF calculation framework is proposed based on a 2-phases calibration model. In the first phase, we consider the dilution and auto-purification process of multi-pollutants in natural waters based on a mass-balance model. In the second phase, a comprehensive evaluation method: fuzzy synthetic evaluation is applied to reflect the vagueness exist in evaluation criteria and determine the “threshold” of GWF. The potential application of the improved GWF calculation model was tested with a case study in Beijing. The results show that when the water quality target is set to Grade V, 7.64 × 109–8.52 × 109 m3 GWF would require to assimilate the pollution to meet the water quality standard. The lower limit of GWF threshold based on the improved model decreased by 17.85% in contrast with that calculated by conventional approach. In conventional method, the GWF is totally determined by the critical pollutant−TN so there's no connection with non-critical pollutants. Nonetheless, for the improved model, all pollutants are taken into account with a weighting factor. This study provides an exploration on how the GWF assessment can be advanced from the point of methodology.

An application of the water footprint assessment to optimize production of crops irrigated with saline water: A scenario assessment with HYDRUS

Agriculture, due to a growing scarcity of fresh water resources, often uses low-quality waters for irrigation, such as saline waters. However, unmanaged applications of such waters may have negative environmental and economic consequences. Based on the concept of the water footprint (WF), a measure of the consumptive and degradative water use, the field-calibrated and validated HYDRUS (2D/3D) model was applied to find optimal management scenarios (from 1980 different evaluated scenarios). These scenarios were defined as a combination of different salinity rates (SR), irrigation levels (IL, the ratio of an actual irrigation water deth and a full irrigation water depth), nitrogen fertilization rates (NR), and two water-saving irrigation strategies, deficit irrigation (DI) and partial root-zone drying (PRD). The consumptive WF was defined as the crop water consumption divided by the crop yield. The grey WF was calculated for the N fertilizer and defined as the volume of freshwater required to dilute nitrogen (N) in recharge so as to meet ambient water quality standards. Simulated components of water and solute dynamics were used to calculate criteria indices, which were divided into two groups: (a) environmental indices, including the degradative grey water footprint (GWF) and the apparent N recovery rate efficiency (ARE), and (b) economic indices, including economic water (EWP) and land (ELP) productivities. While significant improvements of 3.9–59.2%, 0.1–165.8%, and 0.01–166.5% in ARE, EWP, and ELP, respectively, were obtained when NR varied within the range of 0–200 kg ha−1, changes in these indices were relatively minor when NR was higher than 200 kg ha−1. At a given NR, GWF tends to increase considerably by up to 180% when DI-crops are subject to low-intermediate salt (SR < 7 dS m−1) and water (IL > 70%) stresses. This is at the expense of up to a 55% reduction in ELP and up to a 120% increase in EWP. With N uptake 0.2–17.3% higher, PRD seems to be a more viable agro-hydrological option than DI in reducing a pollutant load into regional aquifers as well as in sustaining farm economics. The entire analysis reveals that the PRD strategy with N-fertilization rates of 100-200 kg ha−1, a moderate salinity stress (SR < 5 dS m−1), and irrigation levels of 60–90% represents the best management scenario. It can be concluded that, while there is a substantial need for rescheduling irrigation and fertilization managements when crops are irrigated with saline waters, HYDRUS modeling may be a reliable alternative to extensive field investigations when determining the optimal agricultural management practices.

Determination of Grey Water Footprint of Rice Cultivation in the Right Bank of Nilwala Downstream

Excess nutrients released through leaching and/or runoff from agricultural lands into natural water bodies has caused water pollution all over the world. Water pollution by means of discharging chemical substances from paddy fields to water bodies has become a critical problem in Sri Lanka. The grey water footprint is considered as a rough estimate of water pollution associated with a particular activity. The grey water footprint associated with the paddy cultivation in the right bank of Nilwala” downstream was calculated based on two levels of fertilizer applications; level 1: fertilization according to the recommendations of the Department of Agriculture, Sri Lanka and level 2: fertilization based on farmer's preferences. Sampling was performed once a day for a week after each fertilization. Nitrate concentration of water samples was analyzed through Ultraviolet Spectrometric Screening method while pH and electrical conductivity were measured using pH meter and conductivity meter, respectively. Daily rainfall over the study area was recorded throughout the study period. The grey water footprint calculated based on the nitrate discharge for fertilization level 1 and level 2 were 0.93 m3/ha and 2.26 m3/ha respectively. As it is analyzed by the one-sample t-tests, the nitrate concentrations, pH and electrical conductivity of paddy water are significantly lower than that of proposed ambient water quality standards for Sri Lanka. As revealed by two-sample t-tests, nitrate concentrations, pH and electrical conductivity of water samples were significantly different from each other with respect to the both levels of fertilization. However, the nitrate concentrations and electrical conductivity values of water samples related to both levels of fertilization and pH values related to fertilization level 1, were significantly higher than that of raw water in Nilwala river which is used for irrigation, while pH values related to fertilization level 2 were significantly lower than the same. Keywords: Grey water footprint, Paddy cultivation, Nitrate, pH, Electrical conductivity

Impacts of Agricultural Practices on Water Quality in Uma Oya Catchment Area in Sri Lanka

Sustainability of global food production is highly depending on the quality of the environment. In many parts of the world increase of agricultural production heavily depend on intensive agricultural practices which are having negative impact on the environment. The impacts of agricultural practices on surface water quality is given special attention currently since the safe and ample supply of freshwater is fundamental to humans and for the sustainability of ecosystem function. Intensive agricultural practices in river catchments often pose threat to the ecological integrity of river ecosystems. Uma Oya watershed in the upper Mahaweli watershed in Sri Lanka is an intensively cultivated landscape. In most parts of the catchment previously forested lands have been cleared and converted to agricultural lands. However, the empirical evidence on quantitative assessment of such land use conversion impacts on stream ecological health is lacking in the context of river catchments in Sri Lanka. Therefore the present study was aimed at evaluating the agricultural land use impacts on stream physical habitat quality, water quality and macroinvertebrate indices in the Uma Oya catchment at different spatial scales. The relationship between catchment and site scale % agricultural lands, water quality and macroinvertebrate indices were evaluated using univariate and multivariate approaches. The results indicated that stream physical habitat quality, water quality parameters and macroinvertebrate indices are significantly (p<0.05) affected by catchment scale % agricultural land cover. Among the water quality variables that were tested NO2-N, NH3-N, PO4-P and BOD5 level in sites with higher percentage of agricultural land cover exceeded the drinking water quality standards during dry season. PO4-P and BOD5 level in those sites exceeded the proposed ambient water quality standards for inland waters in Sri Lanka for aquatic life and for irrigation purposes. Findings of the present study suggest that catchment scale interventions are crucial for the management of Uma Oya watershed and for the improvement of water quality and sustainable agricultural production.