Which procedures should be followed when collecting industrial effluent samples?

When collecting industrial effluent samples, it is essential to follow a comprehensive approach that encompasses multiple key procedures to ensure the integrity and reliability of the samples. The correct answer includes all aspects vital to effective sampling.

Preserving samples properly is crucial because many pollutants can change in concentration or form after collection due to factors like temperature, light exposure, or chemical reactions. By using techniques such as refrigeration, chemical preservation, or airtight containers, the samples can maintain their original characteristics until analysis.

Following chain of custody procedures is equally important as it ensures the legal integrity of the sample. Chain of custody refers to the process of tracking the sample from the point of collection through to its analysis. It involves documenting each individual who handles the sample, thereby providing transparency and accountability. This traceability is essential, especially in legal or regulatory contexts, where the reliability of the data can impact compliance assessments or litigation.

Using proper sampling techniques is also a fundamental requirement for obtaining representative samples. This involves selecting appropriate locations, times, and methods of collection to ensure that the samples accurately reflect the effluent being discharged. Techniques such as grab sampling or composite sampling each have specific protocols to follow based on the pollutant being measured and the characteristics of the effluent.

Taken together, these procedures ensure