What is the main cause of most erroneous lab results in water testing?

The main cause of most erroneous lab results in water testing is sampling error. Sampling error occurs when the sample collected does not accurately represent the entire body of water being tested. This can happen for various reasons, such as improper sample collection techniques, the use of contaminated sampling containers, or failure to properly mix the water before taking a sample. Since laboratory results are heavily reliant on the accuracy and representativeness of the samples collected, any error during the sampling process can lead to misleading results, ultimately impacting decisions made about water quality and safety. It emphasizes the importance of following standardized sampling protocols to ensure the integrity of the samples used for subsequent laboratory analysis.