Preliminary Study on Formulating Water Quality Standards for Estuaries of China

In China,the water quality standards in operation include the Environmental Quality Standard for Surface Water（GB3838-2002）and Water Quality Standards for Seawater（GB3097-1997）.However,these two standards are currently not suitable for the estuarial zones of China because of the unique properties of water environment in estuaries.We proposed preliminarily a basic idea and technical workflow in formulating water quality standards for the estuaries of China based on analyzing the water environment properties of estuaries comprehensively and comparing various parameters and their standard values mentioned in these two standards above.Issues pertinent to the formulation of the water quality standards for estuaries,e.g.nutrient,heavy metals and persistent organic pollutants（POPs）,are highly concerned.The objective of this paper is to provide technical support for the formulation of scientific water quality standards and the assessment of water quality of the estuaries of China.

Research Status of Water Quality Criteria and Standards and Analysis on the Transformation Methods

Under the vision of development for the new era,China has entered a stage of high-quality economic development and an important window period in which we have the conditions and ability to address the prominent issue of economic development and ecological protection in a coordinated way.However,all kinds of environmental benchmark values in China are lacking and need to be constantly supplemented and improved.Therefore,exploring and putting forward a simple and efficient method for the transformation of environmental criteria into environmental standards is an important basis for the rapid establishment of relevant environmental criteria system and the effective promotion of the development of environmental standards system towards a scientific and reasonable direction.In this paper,the water environment is taken as the research object.By analyzing the research progress of environmental criteria and standards at home and abroad,and the foreign method of transforming environmental criteria into environmental standards,combined with the problems faced in the process of transforming environmental criteria into environmental standards in China,an effective method to transform China's environmental criteria into environmental standards is analyzed.After analysis and comparison,it is found that the pollution reduction accounting method could achieve their simple and efficient conversion.Under the premise of obtaining environmental criteria for certain pollutants,environmental criteria for certain pollutants could be obtained by distributing pollutants reduction costs,and accounting economic benefits after reaching standard,thus obtaining the environmental standard of this type of pollutant,which provides reference to determine the environmental standard limits of such pollutants.

Surface Water Quality Profiling Using Physicochemical Parameters in Open Defecation Free and Non-Open Defecation Free Local Government Areas in Benue State, Nigeria

Physicochemical parameters of surface water sources in the study of local government areas (LGAs) were assessed using standard procedures. The mean physicochemical parameters for pH (5.49), NO2 (0.23 mg/L), SO4 (0.77 mg/L), Na (28.72 mg/L), Ca (28.94 mg/L), Mg (17.50 mg/L), Cl (11.65 mg/L), TSS (6.27 mg/L), TDS (104.23 mg/L), BOD (2.83 mg/L) and F (0.87 mg/L) were below WHO standards irrespective of their defecation status. The values for electrical conductivity (EC) (2770.50 µs/cm, turbidity (481.24 NTU), dissolved oxygen (DO) (5.32 mg/L), chemical oxygen demand (COD) (445.50 mg/L), K (125.06 mg/L), PO4 (0.78 mg/L) and Fe (0.57 mg/L) were above the WHO limits for safe water. Higher EC and COD values obtained in the study is evidence of pollution of the water sources by organic matter.

Development of emergency water quality standard for Cr^(6+) and Hg^(2+) in Liao River basin

The acute toxicity data of Cr＋ and Hg2＋ to the aquatic organisms in Liao River basin was collected and screened. Calculated results of criteria values using popular species sensitivity distribution （SSD） methods were evaluated through data analysis. The comprehensive methodology of emergency water quality standards （EWQSs） was established on the basis of the SSD method of Australia and New Zealand according to the evalu- ation results. The affected fractions of the aquatic organisms were set to be 5 %, 15 %, 30 % and 50 %, corre- sponding to the risk grades of Ⅰ,Ⅱ,Ⅲ and IV, and four-grade EWQSs, respectively. The EWQSs for Cr6＋ and Hg2. in the Liao River were derived and the corresponding risk indicators were also proposed. The results showed that the four-grade EWQSs for Cr6＋ were 2.85 μg/L, 21.0 μg/L, 161 μg/L and 797 μ/L, respec- tively, and the risk indicators were daphnia （grade Ⅱ ）, shrimp （grade Ⅲ）, and the bighead fish or tadpole （grade IV）. The four-grade EWQSs for Hg2＋ were 0.59 μg/L, 2.32 μg/L, 6.25 μg/L and 15.6 μg/L, respective- ly, and the risk indicators were crucian carp or daphnia （grade Ⅱ）, shrimp （grade Ⅲ）, and worm or crab （grade IV）. The results provided valuable information for the risk analysis of sudden ambient water environmen- tal pollution accident.

Diagnosis of Lead Pollution of Surface Waters of a River: Case of the Djiri River in the Republic of Congo

This research work focuses on the physico-chemical analysis of surface water from the Djiri River with the aim of preventing the population against possible water pollution. The analysis of samples taken from the Djiri river revealed the presence of lead in these waters at levels exceeding the WHO guideline values: an average annual pollution (0.93 mg/l) which is visibly higher than the value. WHO guide (0.01 mg/l) in situ data from the Djiri River revealed a significant drop in flow between the 2016 period characterized by a divergence index of 0.82344, thus highlighting a hydrological situation for which national hydrological stakeholders will absolutely have to implement measures, remedial measures or mechanisms to protect this river against possible disappearance by elimination of lead in the water.

Determination of water environment standards based on water quality criteria in China:Limitations and feasibilities

There is a need to formulate water environment standards（WESs） from the current water quality criteria（WQC） in China.To this end,we briefly summarize typical mechanisms applied in several countries with longer histories of developing WESs,and three limitations to formulating WESs in China were identified.After analyzing the feasibility factors including economic development,scientific support capability and environmental policies,we realized that China is still not ready for a complete change from its current nation-wide unified WES system to a local-standard-based system.Thus,we proposed a framework for transformation from WQC to WESs in China.The framework consists of three parts,including responsibilities,processes and policies.The responsibilities include research authorization,development of guidelines,and collection of information,at both national and local levels;the processes include four steps and an impact factor system to establish water quality standards;and the policies include seven specific proposals.

Pilot study for the treatment of sodium and fluoridecontaminated groundwater by using high-pressure membrane systems

High-pressure membrane process is one of the cost-effective technologies for the treatment of groundwater containing excessive dissolved solids. This paper reports a pilot study in treating a typical groundwater in Huaibei Plain containing excessive sodium, sulfate and fluoride ions. Three membrane systems were set up and two brands of reverse osmosis （RO）, four low-pressure RO （LPRO） and one tight nanofiltration （NF） membranes were tested under this pilot study. An apparent recovery rate at about 75% was adopted. Cartridge filtration, in combination with dosing antiscalent, was not sufficient to reduce the fouling potential of the raw water. All RO and LPRO systems （except for the two severely affected by membrane fouling） demonstrated similar rejection ratios of the conductivity @98.5%）, sodium （-98.5%） and fluoride （-99%）. Membrane fouling substantially reduced the rejection performance of the fouled membranes. The tight NF membrane also had a good rejection on conductivity （95%）, sodium （94%） and fluoride （95%）. All membranes rejected sulfate ion almost completely （more than 99%）. The electricity consumptions for the RO, LPRO and NF systems were 1.74, 1.10 and 0.72 kWh·m3 treated water, respectively. The estimated treatment costs by using typical RO, LPRO and tight NF membrane systems were 1.21, 0.98 and 0.96 CNY·m 3 finished water, respectively. A treatment process consisting of either LPRO or tight NF facilities following multi-media filtration was suggested.