Turbidity monitoring for aquatic ecosystem assessment and its applicability to mine tailings management and watercourse crossing construction

The measurement of turbidity in water by nephelometry can produce instant results allowing for immediate, on-site, well-informed management decisions. This study contributes to the validation of nephelometric turbidity as a valuable aquatic ecosystem monitoring tool as well as makes recommendations for solutions to reduce the incongruities in regulatory guidelines. A comprehensive literature survey and case study supported a site specific relationship between turbidity and suspended sediment with some validity of a 3 to 1 total suspended sediment to turbidity ratio. The analysis methodologies for total suspended sediment and turbidity were essential to the correlation. The field turbidity relative to the laboratory total suspended sediment provided the most consistent relationship. A comparison between on-site analysis of turbidity versus laboratory analysis conducted days after sampling demonstrated that elapsed duration between sampling and analysis may produce variable results. Limitations in the Canadian Environmental Quality Guidelines turbidity exceedence guidelines were reviewed.