Related by context. Frequent words. (Click for all words.) 44 contaminant 43 trichlorethylene 43 groundwater contamination 42 contaminants 42 groundwater 41 hexavalent chromium 40 contaminated groundwater 40 perchlorate 39 fecal coliform bacteria 39 Contaminants 39 chromium 39 Perchlorate 39 pesticide residue 38 arsenic 38 fecal coliform 38 Toxic Substances Control 38 Safe Drinking Water 38 tritium 37 PCB contamination 37 PFOS 37 hydraulic fracturing 37 pesticide residues 37 sediment 37 Clean Water Act 37 turbidity 37 pollutant 37 endocrine disruptors 37 radium 37 septic systems 36 contaminated 36 selenium 36 wastewater discharge 36 watersheds 36 ATSDR 36 trihalomethanes 36 contamination 36 E. coli bacteria 36 PCBs 36 pollutants 36 mercury contamination 35 chemicals 35 TMDL 35 trace amounts 35 hydrogen sulfide 35 radionuclides 35 toxic chemicals 35 carcinogen 35 atrazine 35 Cryptosporidium 34 groundwater pumping 34 picocuries per 34 Superfund sites 34 PFOA 34 Groundwater 34 toxic substances 34 aquifers 34 TSCA 34 dissolved oxygen 34 nitrates 34 MDEQ 34 fecal bacteria 33 spokeswoman Kendra Barkoff 33 EPA 33 toxins 33 aquifer 33 IEPA 33 pesticide 33 Great Lakes basin 33 sulfates 33 Superfund site 33 contaminated soil 33 triclosan 33 hazardous chemicals 33 benzene 33 Environmental Protection Agency 33 nitrate 33 Water Quality 33 Pollutants 33 vinyl chloride 33 coliform 33 fluoride 33 pesticides 32 ppb 32 contaminated soils 32 coal slurry 32 coliform bacteria 32 wastewater 32 TCE 32 toxics 32 nutrient pollution 32 MTBE 32 ozone pollution 32 effluent 32 leachate 32 Atrazine 32 PAHs 32 BPA 32 contaminate drinking 32 Toxic Substances 32 fracking 31 gasoline additive