Evaluation of site-specific water quality guideline performance for aluminum and iron in select surface water monitoring stations in New Brunswick

Abstract

We were interested in the development of Site-Specific Water Quality Guidelines (SS-WQGs) within the Canadian Water Quality Index (CWQI) model, due to high natural background concentration levels of aluminum (Al) and iron (Fe) in some freshwater bodies throughout New Brunswick (NB). This report presents the adaptation and implementation of an existing CCME-approved SS-WQG method called the background concentration (BC) procedure, into the CWQI model. The effects of using five different BC based SS-WQGs (mean; median; mean + SD; 90th percentile; mean + 2SD) at eight selected reference monitoring stations across NB are examined and compared. The recommendations for SS-WQGs for Al and Fe at eight reference stations are also provided in this report. Mean + 2SD was observed to give the highest WQI scores improvement among the five BC-based SS-WQGs. Keywords: aluminum, iron, site-specific water quality guidelines, background concentration procedure, water quality index, CCME, New Brunswick