Contamination Pollution Bacterial Contamination Contaminated Water Contaminants Fecal Bacteria Pollution Effects Microplastics in Water Contamination Sources Public Health Risks Fluoride in Drinking Water Bioindicators Nitrate Exposure Contamination Investigation Oxygen Levels Hazardous Chemicals Toxins Public Bathing Areas E. coli Contamination E. coli Pollutants Bacteria Levels