Related by context. Frequent words. (Click for all words.) 65 turbidity 64 contaminants 64 E. coli bacteria 60 dissolved oxygen 60 E. coli 59 bacterial contamination 59 contaminant 59 arsenic 56 E.coli 56 contamination 55 dioxin 55 E coli 54 hydrogen sulfide 54 tritium 53 bacteria 53 nitrates 53 dioxins 53 groundwater 53 pollutants 52 pollutant 52 selenium 52 untreated sewage 51 raw sewage 51 algae blooms 51 hexavalent chromium 51 effluent 51 fecal matter 50 PCBs 50 nitrate 50 chloride 50 toxin 50 phosphorus 50 toxins 49 bacterial 49 groundwater contamination 49 cyanobacteria 49 septic systems 49 phosphorous 49 algae bloom 49 stormwater runoff 49 sediment 48 trace amounts 48 ppb 48 harmful bacteria 48 chlorine 48 radium 48 leachate 48 perchlorate 48 mercury 47 contaminated 47 chromium 47 benzene 47 radioactive iodine 47 West Nile virus 47 salmonella 46 norovirus 46 Contamination 46 algae 46 zebra mussels 46 West Nile Virus 46 Water Quality 46 Arsenic 46 salmonella contamination 46 TCE 46 toxic substances 46 radioactivity 45 toxic chemicals 45 sewage 45 septic tanks 45 PBDEs 45 salinity 45 polluted 45 carbon monoxide 44 PFOA 44 Salmonella 44 tributaries 44 toxicity 44 discharges 44 fluoride 44 tributary 44 radon 44 Clean Water Act 44 seepage 44 cadmium 44 wastewater 44 chlorination 43 hazardous chemicals 43 melamine 43 lakes 43 hazardous substances 43 pollution 43 sedimentation 43 WNV 43 smallmouth bass 43 volatile organic compounds 43 concentrations 43 listeria 43 creek 43 DEQ 43 septic 43 sulfate