The technical requirements for groundwater quality monitoring schemes involve various technical specifications and standards, aiming to ensure the accuracy, reliability, and repeatability of monitoring results. The following are the main technical requirements for the groundwater quality monitoring plan:
1. Monitoring purpose and objectives
Clear purpose: The monitoring plan should specify its purpose, such as assessing the pollution status of groundwater, monitoring the trend of water quality changes, and evaluating whether the water quality meets relevant standards.
Clear objectives: Determine sampling points, sampling frequency, monitoring parameters, etc. based on monitoring objectives to ensure comprehensive and accurate reflection of groundwater quality.
2. Selection and delineation of monitoring areas
Regional division: Based on the groundwater basin, distribution of pollution sources, and possible spread of pollution, the monitoring area is delineated. Select representative monitoring points that cover potential pollution sources, groundwater recharge areas, discharge areas, etc.
Sampling point selection: Sampling points should be selected based on the flow direction of groundwater, the diffusion law of pollutants, and the distribution of water sources to ensure the representativeness of the samples.
3. Sampling requirements
Sampling frequency: Determine the appropriate sampling frequency based on the pattern of water quality changes, monitoring objectives, and local hydrological and climatic conditions. Normally, when the concentration of pollutants is high, the sampling frequency should be increased.
Sampling depth and method: Select different sampling depths based on the structure of the groundwater layer. Multi layer sampling methods are usually used for monitoring to comprehensively reflect the water quality conditions of different water layers.
Sampling containers and equipment: The containers and equipment used during the sampling process should comply with national or international standards to ensure that they do not affect the quality of the water sample. For certain specific pollutants (such as organic matter, heavy metals, etc.), dedicated and non polluting containers should be used.
On site processing and preservation: After water sample collection, the changes in pollutants in the water sample should be minimized as much as possible according to the different analysis items, and analysis should be carried out within the specified time. If long-term storage is required, appropriate refrigeration and chemical stabilizers should be used.
4. Selection of monitoring parameters
Conventional water quality parameters include pH, dissolved oxygen (DO), conductivity (EC), temperature, total hardness, ammonia nitrogen, nitrite, nitrate, etc.
Pollutant indicators: Monitor organic pollutants (such as volatile organic compounds, petroleum, pesticides, etc.), heavy metals (such as lead, mercury, cadmium, chromium, etc.), radioactive substances, pathogenic microorganisms, etc. for possible pollution sources.
Special monitoring: If groundwater is subject to special pollution (such as oil spills, chemical pollution, etc.), relevant monitoring items for special pollutants should be added.
5. Data collection and processing
Data collection: Scientific monitoring equipment and automated monitoring systems are used for data collection to ensure the real-time and accuracy of monitoring data. Suitable sampling periods, sampling depths, and data backups should be set.
Data analysis and comparison: The collected data should be compared with relevant water quality standards (such as national or local water quality standards, drinking water standards, etc.), and trends and conclusions should be drawn through statistical analysis methods.
Data quality control: Ensure the accuracy and reliability of data, adopt standardized operating procedures, and regularly perform instrument calibration and validation.
6. Instrument and equipment requirements
Accuracy and stability: Choose high-precision and stable monitoring instruments, such as water quality automatic analyzers, heavy metal detectors, gas chromatographs, etc.
Calibration and maintenance: Monitoring instruments should be regularly calibrated and maintained to ensure stability and accuracy during long-term use.
Online monitoring system: For long-term monitoring projects, it is recommended to use an online monitoring system that can collect data in real time, store and transmit data, and reduce human operational errors.
7. Quality assurance of monitoring data
Quality Control (QC): During the monitoring process, quality control measures should be taken, such as blank samples, parallel samples, recovery rate experiments, etc., to ensure the accuracy and reliability of the data.
Quality assessment: Regularly evaluate the quality of monitoring data, including accuracy, precision, repeatability, etc., to ensure that monitoring results meet standard requirements.
8. Report and Analysis
Data report: Monitoring data should be summarized in a timely manner and generate clear and standardized reports. The report should include monitoring areas, time, monitoring parameters, monitoring results, analysis and conclusions, etc.
Trend analysis: Based on monitoring data, conduct trend analysis and early warning, identify possible water quality deterioration or pollution sources, and provide effective suggestions for water quality improvement.
Emergency response: If the monitoring results show serious groundwater pollution or emergencies, relevant departments should be promptly reported and emergency response measures should be taken.
9. Environmental Protection and Regulatory Requirements
Regulatory compliance: All monitoring activities should comply with local water quality monitoring regulations and standards (such as the "Groundwater Quality Standards" GB/T14848, etc.).
Environmental protection requirements: The disposal of waste during the monitoring process should comply with environmental protection requirements and avoid secondary pollution.
10. Personnel training and technical support
Technical personnel requirements: Monitoring personnel should have relevant professional backgrounds, undergo systematic training, and be familiar with equipment operation, sampling processes, data processing, and other aspects.
On site technical support: Regularly provide technical support and equipment inspections to ensure efficient and error free monitoring work.
By implementing these technical requirements, it is possible to ensure that groundwater quality monitoring meets high standards in terms of scientificity, standardization, accuracy, and reliability, providing strong support for water resource management, pollution prevention and control, and water environment protection.