Thread Content
1 Basic Concepts 1. Environmental monitoring can be divided into three categories based on its purpose: surveillance monitoring, monitoring for specific purposes, and research-oriented monitoring. 2. What are the characteristics of environmental pollution? Spatial distribution, temporal distribution, the relationship between environmental pollution and pollutant concentrations, the combined effects of various pollution factors, and the social assessment of environmental pollution. 3. What are the characteristics of environmental monitoring: comprehensiveness, continuity, and traceability. 4. What are environmental standards? Environmental standards are the benchmarks used to assess environmental quality and evaluate the effectiveness of environmental protection efforts. They represent the actions taken in various environmental-related areas aimed at preventing environmental pollution and promoting a healthy ecological cycle. 5. Into how many levels and categories are environmental standards divided? The classification follows a \"three-level, six-category\" standard system: (1) Three levels: national level, local level, and industry level; (2) Six categories of environmental protection standards: including environmental quality standards, pollutant emission standards, basic environmental standards, environmental method standards, standards for environmental reference materials, and standards for environmental protection instruments and equipment. 6. What are environmental quality standards? Environmental quality standards are regulatory requirements regarding harmful substances and factors in the environment, which are established based on environmental quality benchmarks and taking into account factors such as social, economic, and technical aspects. 7. The \"Comprehensive Wastewater Discharge Standards\" classify the pollutants discharged into two categories based on their nature and methods of control: Category 1 pollutants (metals) are sampled at the outlets of workshops or wastewater treatment facilities, while Category 2 pollutants (organics) are sampled at the outlets of the entities that discharge wastewater. 2. Monitoring of water and wastewater 1. Self-purification of water bodies: Once pollutants enter a water body, they are first diluted, and then undergo a series of complex physical, chemical changes and biological transformations such as volatilization, coagulation, hydrolysis, complexation, redox reactions, and microbial degradation, thereby reducing the concentration of pollutants. This process is known as the self-purification of water bodies. Water pollution: When the amount of pollutants discharged exceeds the water body’s self-purification capacity, it leads to the accumulation of pollutants and a continuous deterioration of water quality, resulting in water pollution. 2. Chemical Oxygen Demand (COD) refers to the amount of oxidant consumed to oxidize the reducing substances in 1 liter of water sample, expressed in mg/L of oxygen. Reducing substances in water include organic compounds as well as inorganic substances such as nitrites, sulfides, and ferrous salts. (1) Potassium dichromate method (2) Potassium permanganate index method. 3. Biological Oxygen Demand (BOD) refers to the amount of dissolved oxygen consumed by aerobic microorganisms during the biochemical oxidation of organic substances in water, under conditions of sufficient dissolved oxygen. 4. The \"Environmental Quality Standards for Surface Water\" classify monitoring parameters into several categories in order to meet the requirements related to the uses of surface water and the quality of the ecological environment. These categories are: (1) Basic parameters; (2) Additional parameters for sources of centralized drinking water; (3) Specific parameters for sources of centralized drinking water. 5. Pollutant forms refer to the chemical state, oxidation state, and isomeric forms in which pollutants exist in the environment. 6. The principles for setting up monitoring sections should be to establish such sections where there are changes in water quality and quantity, as well as in the functional areas designated for different uses of the water body. (1) Residential and industrial areas where large amounts of wastewater are discharged into rivers, as well as areas upstream and downstream of such areas; (2) The main inlets and outlets of lakes and reservoirs; (3) Areas with functional roles such as drinking water sources and water resource zones; (4) The estuaries of rivers that flow into the sea, as well as upstream of the confluence points of larger tributaries and the areas where these tributaries mix with the main stream after convergence; (5) The inlets and outlets of international rivers at their points of crossing international boundaries; (6) Locations that coincide as much as possible with hydrological measurement stations. Setting of monitoring sections: To evaluate the water quality of intact river systems, it is necessary to establish background sections, control sections, reference sections, and reduction sections. For a given river section, only three cross-sections need to be set: control, reference, and reduction (or transit). 7. What is the type of water sample? Instantaneous water sample – collected randomly at a specific time and location. Mixed water sample: A water sample obtained by mixing instantaneous water samples collected at the same sampling site but at different times. Composite water sample: A mixture of instantaneous water samples collected simultaneously from different sampling points. 8. What are the methods for preserving water samples? Freezing or refrigeration, preservation by adding chemical reagents, and filtration or centrifugation of the water samples. 9. The digestion of water samples is divided into wet digestion and dry digestion. Wet digestion is further categorized into: (1) HNO3: cleaning the water sample ； (2) HNO3-HClO4: Organic compounds that are difficult to oxidize ； (3) HNO3-H2SO4: (5:2) ； (4) HNO3-H3PO4: Eliminate Fe3+ interference ； (5) HNO3-KMnO4: Determination of Hg ； (6) Multiple elimination ； (7) Alkaline decomposition method. 10. What are the methods for enriching and separating water samples? (1) Stripping, headspace, and distillation methods: volatile components ； (2) Extraction method ； (3) Adsorption method ； (4) Ion exchange method ； (5) Co-precipitation method. 11. Methods for determining the colority of water samples (1) Platinum-cobalt standard colorimetry. This method is suitable for determining the colority of clean natural water and drinking water with a yellow tint. (2) Dilution factor method: This method is suitable for the determination of surface water contaminated by industrial wastewater and the color of such wastewater. 12. Methods for testing water samples: type printing method, Cessie dish method (on-site). 13. The color of water can be divided into true color and apparent color; the chroma of water generally refers to the true color. 3 Air and Exhaust Gas Monitoring 1. What is air pollution? The extensive use of coal and oil generates large amounts of harmful substances such as dust and SO2. When their concentrations exceed the limits allowed by the environment and persist for a certain period of time, it alters the normal composition of the air, disrupts the natural physical, chemical, and ecological balance, endangers human health, and damages natural resources. This condition is known as air pollution. 2. Pollutants are classified into several categories. China’s \"Comprehensive Emission Standards for Air Pollutants\" specify emission limits for 33 types of pollutants. Based on the formation process of air pollutants, they can be divided into Category I pollutants and Category II pollutants. Primary pollutants are harmful substances that are directly emitted into the air from various sources of pollution. Secondary pollutants are new pollutants that are formed as a result of the interaction of primary pollutants in the air, or through reactions with normal components present in the air. Based on their form of existence, air pollutants can be divided into molecular-form pollutants and particulate-form pollutants. 3. Methods for selecting sampling points in air monitoring (1) Functional zone method: Industrial areas where pollution is concentrated and residential areas with a high population density. Applicable for regional routine testing. (2) Grid sampling method: Areas with multiple pollution sources and a relatively even distribution of these sources. Uniform grid squares, intersection points and square centers. (3) Concentric circle method: It is commonly used in areas where multiple pollution sources form a pollution cluster, with the larger pollution sources being concentrated in one area. Draw concentric circles with the center of the polluted group as the center, and take the intersection points of the radii with the circle as sampling points. (4) Sectoral layout method: Areas with isolated elevated point sources and a distinct dominant wind direction. The point source is at a fixed position, and a fan-shaped area is drawn with the downwind direction as the axis. The fan angle ranges from 45 to 90 degrees. 4. What are the methods for collecting air samples? There are two types: direct sampling and enrichment (concentration) sampling. (1) The direct sampling method is applicable when the concentration of the component to be measured is high or the monitoring method has high sensitivity. The results obtained by this method are the instantaneous concentration or the average concentration over a short period of time. (2) Enrichment sampling method is applicable: when the concentration of pollutants is low (ppm–ppb). The sampling time is generally long, and the results obtained can represent the average concentration during the sampling period, thus reflecting the true situation of air pollution more accurately. 5. What are the two **standard analytical methods for determining SO2 in the atmosphere? Potassium mercuric tetrachloride absorption–salicyl aniline hydrochloride (national standard method) ； Formaldehyde absorption-salicylaldehyde hydrochloride (national standard method). 6. Methods for determining the sulfation rate include the lead dioxide-weight method, the alkali tablet-weight method, the alkali tablet-barium chromate spectrophotometric method, the alkali tablet-ion chromatography method, etc. 7. Methods for determining smoke blackness: Ringelmann blackness scale method, smoke measuring telescope method, photoelectric smoke meter method. 4. Monitoring of solid waste: 1. What is solid waste? It refers to solid or semi-solid waste materials that pollute the environment and are generated in activities such as production, construction, daily life, and other operations. 2. What are hazardous wastes? They refer to wastes that are listed in the **Catalogue of Hazardous Wastes**, as well as those identified as hazardous in accordance with the criteria for determining hazardous wastes set by the environmental protection authorities of the State Council. Class 49, 133 types. 3. If household waste is disposed of by landfilling, what testing experiments are required? (1) Determination of biodegradability ； (2) Leachate analysis: If municipal waste is disposed of by incineration, the calorific value needs to be measured. 4. What are the main harmful characteristics of hazardous waste? Flammability, corrosivity, reactivity, radioactivity, leachate toxicity, acute toxicity, and other toxicities. 5. What are the main methods for dealing with household waste? Incineration, sanitary landfilling, composting. 5 Soil quality monitoring: 1. What are the basic properties of soil? (1) Absorbency (2) Acidity and alkalinity (3) Oxidation-reduction properties. 2. Soil background values refer to the contents of various components and elements in soil when it is not affected or disturbed by human activities. 3. Principles for the placement of sampling points: (1) Reasonably divide the sampling units. (2) For soil pollution monitoring, monitoring stations are set up wherever there is pollution. (3) Sampling points must not be set at the edges of fields, ditches, roads, or fertilizer piles, nor in areas with severe soil erosion or damaged topsoil. Number of sampling points: Determined based on factors such as the purpose of monitoring, the size of the area, and its environmental conditions. Generally, each sampling unit should have at least 3 sampling points. Sampling point placement method: (1) The diagonal placement method is suitable for fields with a small area and flat terrain that are irrigated with sewage or polluted river water. (2) The plum blossom pattern sampling method is suitable for plots with a small area, flat terrain, and relatively uniform soil composition and pollution levels. (3) The grid layout method is suitable for plots of moderate size with flat terrain and an open, intact landscape; generally, more than 10 sub-points are established. This method also applies to soil contaminated by solid waste, and more than 20 sampling points should be established. (4) The serpentine layout method is suitable for fields that are large in area, have uneven terrain, and uneven soil. (5) The radial sampling method is suitable for atmospherically polluted soils. (6) Grid point placement method. Suitable for plots with gentle terrain. This method is commonly used for investigating chemically polluted soils and soil background levels in agriculture. For comprehensively polluted soils, a method that combines two or more sampling approaches can also be employed. 6 Quality Assurance for Environmental Monitoring 1. Error: The difference between the measured value and the true value is called measurement error. 2. Deviation: The difference between a single measurement value and the average of multiple measurements. 3. Accuracy: A measure of the degree of agreement between the measured value and the true value. It is a comprehensive indicator that reflects both the systematic errors and random errors present in an analytical method or measurement system, and it is expressed in terms of absolute error and relative error. 4. Precision: The degree of consistency of the measurement values obtained by repeatedly analyzing the same sample using a specific analytical procedure under controlled conditions; it is a measure of how well the measurement values match the average value. It is an indicator that reflects the random errors present in an analytical method or measurement system, and is expressed in terms of standard deviation and relative standard deviation. 5. Sensitivity: It refers to the degree of change in the response of this method to a change in the concentration or amount of the substance being tested per unit. It can be described by the ratio of the instrument’s response or some other indicator value to the corresponding concentration or amount of the substance being tested; therefore, the slope of the standard curve (△Y/△X) is commonly used to measure sensitivity. 6. Blank test: A measurement performed using distilled water in place of the sample. It reflects the magnitude of the response value, which is influenced by impurities in the reagents added, the operating environment, and other factors. 7. Control test: A measurement carried out using a standard substance in place of the sample. It is used to verify the reliability of analytical methods, etc. 8. What are the methods for evaluating the accuracy of analytical results? Parallelism, repeatability, reproducibility.