Related by context. Frequent words. (Click for all words.) 60 contaminating groundwater 59 polluting groundwater 58 Soil erosion 57 polluted groundwater 57 contaminate groundwater 57 polluting waterways 56 Septic tanks 56 toxic residues 55 decaying vegetation 55 nitrate contamination 55 radioactively contaminated 54 salinization 54 Contaminated soil 53 groundwater aquifers 53 ponded 53 streambanks 53 toxic waste 52 evaporation ponds 52 Controlled burns 52 recharge groundwater 52 Radioactive waste 52 lakeshores 52 salination 52 streambeds 52 wastewater effluent 51 sewage effluent 51 rotting vegetation 51 compost heaps 51 sludges 51 sediment runoff 51 quaggas 51 creeks rivers 51 pollute groundwater 51 acidify 51 phosphate mines 51 Toxic chemicals 51 reed beds 51 carelessly discarded 50 peat swamps 50 PCBs polychlorinated biphenyls 50 tailing ponds 50 contaminating 50 contaminants 50 Stormwater runoff 50 toxic byproducts 50 bioaccumulation 50 settling ponds 50 Lake Natron 50 toxic algae blooms 50 contamination 50 sewage discharges 50 contaminate 50 inland bays 50 contaminate drinking 50 plankton blooms 50 seepages 50 groundwater 50 silts 50 revegetated 49 chemically contaminated 49 shallow aquifer 49 phosphorus runoff 49 oxygenating 49 contaminates 49 pollute waterways 49 toxic wastes 49 waterways 49 middens 49 freshwater habitats 49 Suisun Marsh 49 Invasive plants 49 soil salinity 49 groundwater depletion 49 toxic chemicals 49 polluted 49 indiscriminate dumping 49 tunicates 49 toxins 49 animal droppings 49 contaminated 49 odors emanating 49 faecal contamination 49 inter tidal 49 freshwater mussels 49 gully erosion 48 deplete oxygen 48 naturally occurring arsenic 48 sediment 48 manure lagoons 48 riparian zones 48 goose droppings 48 unburnt 48 herbicides pesticides 48 poisons 48 ponds 48 stormwater ponds 48 fecal material 48 spillages 48 cogon grass 48 lagoons 48 corrosive acid