Related by context. Frequent words. (Click for all words.) 69 PCBs 56 toxic chemicals 55 dioxins 53 pollutants 53 contaminants 52 dioxin 52 volatile organic compounds 51 hazardous substances 50 Superfund site 50 hazardous waste 50 toxins 50 hazardous chemicals 49 arsenic 49 mercury contamination 49 toxic substances 49 groundwater contamination 48 contaminated soil 48 PFOA 48 carcinogens 48 mercury 48 hexavalent chromium 47 asbestos fibers 47 VOCs 47 contaminated groundwater 47 contaminant 47 PBDEs 47 toxics 46 harmful chemicals 46 hazardous wastes 46 untreated sewage 46 pollutant 46 solvents 46 toxic waste 46 fecal coliform 45 carcinogen 45 PAHs 45 raw sewage 45 TCE 45 contaminated 45 toxin 45 toluene 44 mercury pollution 44 benzene 44 flame retardants 44 mercury emissions 44 nitrogen oxide 44 nitrates 44 chemicals 44 tritium 43 discharges 43 PFCs 43 sediment 43 methylmercury 43 toxic 43 coal tar 43 Superfund sites 43 coliform bacteria 43 phthalates 43 particulate matter 42 perchlorate 42 asbestos 42 phosphorous 42 human carcinogen 42 sewage sludge 42 biosolids 42 chromium 41 contamination 41 diesel exhaust 41 coal ash 41 neurotoxin 41 sulfur dioxide emissions 41 nitrogen oxides 41 Arsenic 41 radium 41 sulfur dioxide 41 acid rain 41 creosote 41 Benzene 40 nitrogen oxide emissions 40 phosphorus 40 phthalate 40 cadmium 40 particulates 40 hydrogen sulfide 40 hazardous materials 40 tributary 40 sediments 40 sodium hydroxide 40 E. coli bacteria 40 Housatonic River 40 Disease Registry 40 harmful substances 39 sulfates 39 carcinogenic 39 triclosan 39 pollution 39 BPA 39 pesticides 39 Clean Water Act 39 organic compounds 39 polluted