What must be used for the analysis of samples?

The requirement for using DEQ approved methods for the analysis of samples is crucial because these methods ensure that the testing procedures meet specific standards set by the Department of Environmental Quality. By adhering to these approved guidelines, the results of the analysis are more likely to be reliable, accurate, and accepted for regulatory or compliance purposes. DEQ approved methods are designed to handle various pollutants and environmental conditions, guaranteeing that the analysis can effectively identify contaminants in the samples. This approach aligns with best practices in environmental science and regulatory compliance, ensuring that any remedial actions taken based on the results are based on sound scientific evidence. Thus, using DEQ approved methods provides a standardized approach that aligns with environmental regulations and public health considerations.