Lake Whatcom North Shore Water Quality Testing
Herrera designed and implemented a water quality monitoring project to evaluate the impact of on-site septic systems on Lake Whatcom, which serves drinking water to a population of more than 80,000 people in Bellingham, Washington. Due to concerns about this contamination, the Lake Whatcom Water and Sewer District contracted with Herrera to assess the presence of contaminants from septic systems located along 3 miles of the north shore with approximately 100 homes served by septic systems. Herrera reviewed literature and evaluated various septic system detection techniques, and developed an experimental design using multiple techniques for multiple lines of evidence. Herrera prepared a water quality monitoring and quality assurance project plan (QAPP) documenting procedures for sample collection, field data collection, laboratory analysis, data analysis, and quality assurance and control. Herrera implemented the QAPP by monitoring the entire lake shoreline and all discharges in the project area and nearby control (undeveloped) area for the presence of septic system leachate using a hand-held fluorometer to detect low levels of optical brighteners from laundry detergents. Water samples were collected at 15 stations showing elevated concentrations of optical brighteners for analysis of fecal coliform bacteria, E. coli bacteria, phosphorus, chloride, bromide, and MST using qPCR analysis of two types of Bacteroidetes fecal bacteria that are exclusive to the human gut. Monitoring was conducted during three separate periods of high rainfall when the water table is high and lateral transport of septic system drainage is highest. Herrera prepared a detailed scientific report of the project findings that were used for inspecting septic systems located where high human fecal sources were observed and for estimating phosphorus loadings from septic systems to Lake Whatcom.