Related by context. Frequent words. (Click for all words.) 64 polluted groundwater 62 contaminating groundwater 60 shallow aquifer 59 contaminated groundwater 58 Radioactive waste 57 wastewater effluent 57 settling ponds 56 evaporation ponds 56 PCBs polychlorinated biphenyls 56 contaminants 56 Aquifers 56 chlorinated solvents 55 Raw sewage 55 harmful contaminants 55 Hydrogen sulfide 55 sewage effluent 55 carbon tetrachloride 54 groundwater 54 Diesel exhaust 54 Toxic chemicals 54 Sulfur dioxide 53 Pend Oreille River 53 trichlorethylene TCE 53 Conemaugh River 53 Seepage 53 chemically contaminated 53 Controlled burns 53 intermittent streams 53 Sediments 53 ash ponds 53 Stormwater runoff 53 groundwater contamination 53 sumps 53 mussel species 52 mill tailings 52 contaminated soil 52 ultraviolet disinfection 52 Edge Moor 52 contaminate groundwater 52 naturally occurring bacteria 52 suspected carcinogen 52 Floridan Aquifer 52 contaminated soils 52 forested wetlands 52 underground aquifer 52 Pollutants 52 corrosives 52 sediment 52 Atchafalaya rivers 52 unnamed tributary 52 groundwater aquifers 51 fecal material 51 Freight train derails 51 Contaminants 51 Dunkard Creek 51 THMs 51 toxic benzene 51 diked 51 Zebra mussels 51 headwater streams 51 Legionella bacteria 51 pollutants 50 manure pits 50 methylene chloride 50 chlordane 50 Soil samples 50 perchlorethylene 50 dissolved solids 50 Creek tributary 50 frac fluid 50 freshwater mussels 50 larvicides 50 Highly radioactive 50 dewatered 50 Soil erosion 50 groundwater withdrawals 50 heavily polluted 50 Cyanobacteria 50 sewage lagoons 50 wellfields 50 Algae blooms 50 streambeds 50 tetrachlorethylene 50 Sediment 50 sewage lagoon 50 Monocacy River 50 injection wells 50 contaminant 50 contamination 50 deplete oxygen 50 stormwater discharge 50 coalbed methane wells 50 sludges 50 lagoons 50 cattle feedlots 49 Rotenone 49 oxbows 49 Pueblo Reservoir 49 arsenic concentrations 49 polychlorinated biphenyls PCBs 49 contaminated sediments