Faecal bacterial contamination of rivers: Evolution, suitability, and health risk implications for recreational use

The suitability of rivers for recreational purposes is an important issue in public health and water management. A quantitative microbial risk assessment was conducted using a dataset of E. coli concentrations in three Sinaloa rivers from 2013 to 2018 to define the level of faecal contamination and estimate the risks of acquiring gastrointestinal infections (GI) from recreational exposure. Faecal contamination was conditioned by river flow or time (p > 0.05) and increase during summer in urban areas. The national laws classify these rivers as suitable for recreational activities. However, the dose-response model estimated the probability of acquiring GI during recreational use (>1.0 x 10(-4)), which implies the occurrence of 283 and 788 GI annually in adults and children, respectively. This research exposes the risk for the development of GI in the population of the region, especially in children; and justifies the controlling microbiological quality of rivers used for recreational use.