9 conventional indicators for water quality testing

2024.05.28
Erun Environmental Protection

Water is the source of life, and its quality is directly related to human health and survival. Therefore, it is particularly important to conduct regular testing and evaluation of water quality. The 9 conventional indicators of water quality testing are important parameters for measuring water quality. They reflect the degree of pollution and health of water bodies from multiple angles. Erun Environmental Protection Group has been deeply engaged in water quality testing instruments and is committed to water quality protection and environmental protection. 

1.pH value is an important indicator for measuring the acidity and alkalinity of water bodies. It reflects the concentration of hydrogen ions (H+) in water, and the normal range is 6.5-8.5. Too high or too low pH values may cause harm to aquatic organisms, and may also affect the taste and color of water.

2. Dissolved oxygen is the content of oxygen dissolved in water, which is directly related to the survival of aquatic organisms. Too low dissolved oxygen will cause aquatic organisms to die of hypoxia, and will also affect the self-purification ability of the water body.

Dissolved oxygen standards for various types of water (mg/L): 

Class I water quality: not less than 7 

Class II water quality: not less than 6 

Class III water quality: not less than 5 

Class IV water quality: not less than 4 

Class V water quality: not less than 3 

Class V water quality: not less than 2 

3. Chemical oxygen demand is an important indicator for measuring the degree of organic pollution in water. It reflects the amount of oxygen required when organic matter in water is oxidized by chemical oxidants. The higher the COD value, the higher the organic content in the water and the more serious the pollution. 

Drinking water standards (mg/L): 

Class I and Class II water: ≤15 

Class III water: ≤20 

Class IV water: ≤30 

Class V water: ≤40 

4. Biological oxygen demand is an indicator for measuring the rate of biological degradation of organic matter in water. It reflects the amount of oxygen required when organic matter in water is decomposed by microorganisms. The higher the BOD value, the faster the degradation rate of organic matter in water, but it may also mean that there are more organic pollutants in the water.

5. Total organic carbon (TOC) is an indicator to measure the total amount of organic matter in water. It includes all carbon-containing organic matter in water, such as carbohydrates, proteins, fats, etc. The higher the TOC value, the higher the organic matter content in the water and the more serious the pollution. Drinking water standard: no more than 2.0 mg/L 

6. Ammonia nitrogen is an indicator to measure the ammonia nitrogen content in water. Ammonia nitrogen is one of the common nutrients in water, but its excessive content will lead to eutrophication of water bodies, triggering algae to reproduce in large numbers, thus affecting the ecological balance of water bodies. Drinking water standard: should be kept below 0.5 mg/L 

7. Nitrate is an indicator to measure the nitrate content in water bodies. Nitrate is one of the common nutrients in water, but its excessive content will lead to eutrophication of water bodies and may also cause harm to human health. 

8. Nitrite is an indicator to measure the nitrite content in water bodies. Nitrite is a toxic substance, and long-term intake may cause harm to human health. Therefore, monitoring the nitrite content in water bodies is of great significance. 

9. Total coliform bacteria is an indicator to measure the degree of microbial contamination in water bodies.It mainly reflects the pollution of intestinal flora in the water body. Too high total coliform bacteria indicates that the water body is polluted.

In summary, the 9 conventional water quality testing indicators are an important basis for evaluating water quality. By monitoring and analyzing these indicators, we can timely understand the degree of pollution and health of water bodies, and provide a scientific basis for the protection and utilization of water resources. At the same time, these indicators also remind us to strengthen environmental protection awareness, reduce the discharge of pollutants, and protect the water resources on which we depend for survival.

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