TOWARDS A BETTER UNDERSTANDING OF BACTERIAL IMPAIRMENTS AT PUBLIC BEACHES IN IOWA

Many of Iowa’s public beaches that are regularly monitored have exceeded recreational water quality standards for fecal indicator bacteria (E. coli), and are listed as impaired. Significant effort goes into determining the causes of these impairments and drafting plans that target reductions in E. coli. The attainment of bacterial water quality goals requires substantial investment and a long-term commitment to maintaining land-use changes and treatment techniques. In addition to annual monitoring for E. coli, the Iowa Department of Natural Resources has initiated two parallel studies: 1) to better understand the distribution and dynamics of E. coli in the beach environment under variable management and weather conditions, and 2) to determine whether human and animal pathogens are present in these systems.

In 2016, sampling was conducted every two weeks throughout the recreational season (April-October) at three public beaches (Big Creek State Park, Hickory Grove, and McIntosh Woods State Park at Clear Lake) in Iowa. During these visits, grab samples of water and sand were obtained from transects across the swimming areas and the beaches, which were analyzed for E. coli using Coliert IDEXX tests. Simultaneously, a minimum of 200 liters of water were pumped from the knee-deep centerpoint of the swimming area through a prefilter and ultrafilter. These samples were analyzed using quantitative polymerase chain reaction (qPCR) methodologies to determine the concentration of genetic material unique to seven human-specific groups of viruses (adenovirus A; adenovirus B; adenovirus C, D, F; GI norovirus; GII norovirus; enterovirus; and human polyomavirus), swine hepatitis E, bovine polyomavirus, avian influenza A, pepper mild mottle virus, Salmonella, Campylobacter jejueni, and Enterohemorrhagic E. coli.

Results indicate that beach sands contain significant concentrations of E. coli, and that concentrations in the beach sand correlate to concentrations in the water column. E. coli concentrations in the beach waters did not correlate to antecedent precipitation or to the occurrence of viruses and bacterial pathogens tested. Correlation analyses to environmental variables including precipitation, sand moisture, sand and water temperature, goose activity, human activity, and wind direction are ongoing.