Quality Assurance in Environmental Monitoring

Over the past decade, there has been a growing awareness of the need for accountable quality assurance (QA) and control in chemical analysis. In environmental monitoring programs, especially those studying metal contaminants at trace and ultratrace concentrations in natural waters, the sampling, sample storage and sample preparation stages prior to analysis, represent potentially greater sources of error than the chemical analysis. The improvements in data reliability and detection limits when appropriate QA is employed, allow meaningful relationships between the measured concentrations and other physical and chemical parameters to be more reliably interpreted. Published data generated from both field and laboratory studies, frequently show no evidence of QA, yet such data are being used to formulate quality guidelines and as the basis for expensive management actions. So that only quality data forms the basis of regulatory action, it is essential that monitoring data not be published without demonstrable evidence of quality practices in all aspects of the monitoring exercise.