A report from the Huron County Health Unit outlines which beaches are most impacted by E. coli contamination.
Port Blake Beach, Goderich Main beach, and Ashfield Township Park Beach had the highest per cent of sample days exceeding the provincial beach water standard of 200 E. coli CFU/100 ml.
Overall, Huron County beaches exceeded the provincial standard on 17% of the days sampled. Each beach was sampled at least 21 days.
The report says that the source of the E. coli in storm drains and rivers is determined by watershed land use. In rural areas the number main source of E. coli is agricultural (Graves et al., 2007; Kon, Weir, Howell, Lee, & Trevors, 2009).
Septic tanks that are not installed or maintained properly contribute to E. coli concentrations The impact of septic tanks is greatest in clay soils and when the water table is high, such as after heavy rainfall.
Birds are considered to be a significant source of E. coli for freshwater beaches.
Lake Huron water quality can change hourly. It is influenced by a number of factors including watershed land use, rainfall, and wind action. Known sources of E. coli in fresh water lakes are:
- Storm drains and rivers - Septic systems - Groundwater - Birds - Domestic and wild animals - Swimmers
E. coli concentrations are influenced by a number of factors resulting in hourly and daily changes in concentration. Those factors include:
-Wave action - Turbidity (water clarity) - Rainfall - Air temperature - Water temperature - Shape of the coastline - Wind speed and direction - Relative humidity - Lake level - Ultraviolet (UV) light exposure (Francy, 2009)
