The basis and prerequisite for formulating the water sampling plan is that the on-site investigation should be as detailed and accurate as possible. Based on the comprehensive on-site investigation, relevant data should be verified. According to the specific situation, the monitoring items, reasonable sampling sections, sampling points, sampling cycle and sampling frequency, quality control and guarantee measures, as well as implementation plans and safety protection measures should be determined after considering the on-site investigation situation and referring to relevant data.
Formulating a detailed sampling plan helps to eliminate randomness and blindness during sampling, thereby ensuring the representativeness and integrity of the samples. Before formulating the plan, the sampling supervisor should fully understand the purpose and requirements of the monitoring task; clearly understand the situation of the pollution sources to be sampled (process flow, type of wastewater, emission pattern, direction of wastewater pipelines, etc.); and be familiar with the sampling methods, selection of containers for holding water samples, sample preservation and transportation. If there are on-site measurement items, the relevant technical aspects of on-site measurement should also be understood. The sampling plan should include: determining the sampling points, measurement items and quantities, quality assurance measures for sampling, sampling time and route, sampling personnel and division of labor, sampling equipment, on-site monitoring equipment and transportation vehicles, and safety protection measures to ensure, etc.