Related by context. Frequent words. (Click for all words.) 66 polluted 58 waterways 57 sewage overflows 56 Superfund sites 51 pollution 51 watersheds 49 sewage spills 49 polluting 49 pollutants 48 pollutant 48 polluter 48 toxic waste 47 toxic chemicals 47 toxic pollutants 47 wastewater discharge 47 Clean Water Act 47 polluters 47 untreated sewage 47 sewage treatment 46 rivers lakes 46 Superfund site 46 contaminated 45 sewage 45 rivers 45 wetlands 44 hazardous waste 44 watershed 44 raw sewage 44 stormwater runoff 44 trout streams 44 wastewater treatment 44 Superfund 44 wastewater 43 tributaries 43 invasive species 43 pollutes 43 estuary 43 contaminants 43 estuaries 43 toxic substances 43 waterway 43 toxic 42 Pollution 42 shellfish beds 42 air pollution 42 mercury pollution 42 toxins 42 tributary 42 cleanups 42 eyesores 42 toxic algae 41 septic systems 41 river basin 41 storm drains 41 wetland 41 stormwater 41 hazardous chemicals 41 toxics 41 hazardous wastes 41 contaminated groundwater 41 freshwater 41 pollute 41 particle pollution 41 lakes 41 hog farms 40 noxious weed 40 dredging 40 dams 40 densely populated 40 Stormwater 40 dirtiest 40 shorelines 40 cleanup 40 contaminant 40 creeks 40 polluting industries 40 effluent 40 wildlife habitat 40 contaminated soil 40 contaminates 40 noxious 40 Environmental Protection Agency 40 noxious weeds 40 drainage ditches 39 sewage disposal 39 algae blooms 39 sediment 39 endangered species 39 environmentally damaging 39 headwaters 39 siltation 39 phosphorus 39 acid rain 39 zebra mussels 39 ecologically sensitive 39 coal ash 39 brownfields 39 undrinkable 39 Cleanup 39 phosphorous 39 TMDL