Where should you look to find approved methods, besides standard methods?

The most relevant source for approved methods, besides standard methods, is found in 40 CFR 136. This section of the Code of Federal Regulations specifically pertains to the quality assurance and quality control of analytical methods used in the examination of water and wastewater. It establishes procedures for the approval of methodologies, ensuring that they meet the necessary criteria and standards for reliability and accuracy in analytical testing.

In the context of wastewater analysis, 40 CFR 136 outlines both the requirements for methods used in determining pollutant concentrations and the processes for their validation, thus ensuring consistency in testing results across laboratories. Understanding where to find these methods is vital for laboratory analysts, as the selection of appropriate methodologies directly impacts data quality and regulatory compliance.

Other options do not primarily focus on methods for wastewater analysis. For example, 40 CFR 141 deals principally with drinking water quality standards and monitoring requirements. The Environmental Protection Act, while significant in establishing the framework for environmental protection, does not specifically compile the methods utilized in wastewater analysis. Lastly, 40 CFR 200 relates to agency administrative practices and is not focused on analytical methods.