Groundwater quality monitoring is an important means to ensure the safety and sustainable use of groundwater resources. The following are the main standards and key points for groundwater quality monitoring:
1. Monitoring purpose and scope
Monitor changes in groundwater quality and determine whether the water meets national water quality standards, especially for different purposes such as drinking water sources, agricultural irrigation water, and industrial water.
The monitoring area usually includes the main recharge area of groundwater, the vicinity of pollution sources, and the direction of groundwater flow.
2. Monitoring parameters
Common groundwater quality monitoring parameters include:
Physical indicators: such as temperature, chromaticity, turbidity, odor, conductivity, etc.
Chemical indicators:
Routine items: pH value, total dissolved solids (TDS), ammonia nitrogen, nitrate, nitrite, etc.
Toxic and harmful substances: heavy metals (such as lead, mercury, cadmium, arsenic, etc.), organic pollutants (such as benzene, petroleum hydrocarbons, etc.).
Microbial indicators: such as total coliform bacteria, total bacterial count, mold, pathogenic bacteria, etc.
3. Monitoring frequency and time
Long term monitoring: Regular monitoring data, usually including monthly, quarterly, semi annual and other time intervals, determined according to the situation in different regions.
Emergency monitoring: In case of sudden pollution incidents (such as factory wastewater discharge, natural disasters, etc.), it is necessary to increase the monitoring frequency.
4. Sampling method
Selection of sampling wells: Select monitoring wells with strong representativeness, usually in key areas such as upstream groundwater flow and downstream pollution sources.
Sampling time: The appropriate sampling time should be selected based on the flow pattern of groundwater and the variation pattern of pollutants. Avoid sampling under weather conditions such as heavy rain, drought, etc.
Sampling method: Use non polluting sampling equipment to ensure the accuracy of the sampling process. Special attention should be paid to avoiding cross contamination for certain pollutants, such as heavy metals and dissolved organic compounds.
5. Data analysis and processing
Data quality control: Strictly control the quality of monitoring data and eliminate outliers.
Trend analysis: Conduct long-term trend analysis on the collected data to evaluate changes in groundwater quality.
Pollution source identification: Based on monitoring results, pollution source tracking and identification can be carried out, and corresponding control measures can be taken.
6. National and local standards
National standards, such as the "Groundwater Quality Standards" (GB/T14848-2017) and the "Drinking Water Quality Standards" (GB5749-2022), clarify the quality requirements for various types of groundwater.
Local standards: Some regions may develop stricter local standards based on the local water resources and environmental characteristics.
7. Monitoring report and management
Report content: The monitoring report should record in detail the monitoring time, location, parameters, methods, analysis results, etc., propose analysis conclusions, and provide relevant management recommendations based on the results.
Management measures: According to the monitoring results, if water quality exceeds the standard or there is a risk of pollution, it should be reported to the relevant management department in a timely manner and pollution control and governance work should be initiated.
8. Technical support and equipment
Monitoring technology: With the development of technology, underground water quality monitoring is gradually using automated monitoring equipment, online monitoring systems, remote sensing technology and other means for real-time monitoring.
Equipment requirements: Monitoring equipment should comply with national standards and undergo regular calibration and maintenance.
These regulations and requirements can help improve the effectiveness and accuracy of groundwater quality monitoring, thereby ensuring the safety of water resources. If you need more detailed operation guidelines or specific implementation plans, you can refer to relevant standards or contact professional organizations.