Related by context. Frequent words. (Click for all words.) 59 invasive species 54 zebra mussels 46 waterways 46 pollutants 46 freshwater 45 effluent 45 estuaries 44 wastewater 44 pathogens 44 sediment 44 contaminants 44 pathogen 43 sewage 43 cargo ships 42 stormwater runoff 42 Great Lakes 42 toxins 42 microorganisms 42 stormwater 42 estuary 41 raw sewage 41 toxic chemicals 41 bacteria 41 organisms 41 Asian carp 41 lagoons 41 mussels 41 salinity 41 Clean Water Act 41 cruise ships 41 sturgeon 40 algae 40 biosolids 40 container ships 40 toxic substances 40 PCBs 40 waterway 39 bycatch 39 contaminant 39 algae blooms 39 discharges 39 phosphorus 39 oceans 39 wastewater treatment 39 rivers lakes 39 nitrogen 38 freighters 38 pests 38 mercury emissions 38 hazardous substances 38 hazardous waste 38 carp 38 ships 38 pollutant 38 hazardous chemicals 38 mercury pollution 38 Water Quality 38 fisheries 37 pollution 37 freshwater fish 37 lakes rivers 37 coastal waters 37 Baltic Sea 37 prions 37 vessels 37 micro organisms 37 cargo 37 microbes 37 toxic waste 37 carbon dioxide 36 dry dock 36 greenhouse gasses 36 bacterial 36 lakes 36 seawater 36 wild salmon 36 bacterium 36 nematodes 36 contaminated soil 36 cruise ship 36 Waterways 36 wetlands 36 fishery 36 sewage treatment 36 waters 36 atrazine 35 sea otters 35 Lake Huron 35 coho 35 merchant ships 35 northern pike 35 cargo containers 35 storage tanks 35 marine ecosystems 35 ammonia 35 steelhead 35 DEQ 35 trawlers 35 sludge 35 disinfection 35 farmed salmon