The nation's rivers.
D002712:Chlorides / Q000032:analysis; D004739:England; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D010575:Pesticides / Q000032:analysis; D012722:Sewage; D013431:Sulfates / Q000032:analysis; D014481:United States; D014876:Water Pollution / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000032:analysis; D014878:Water Pollution, Radioactive / Q000032:analysis
D002712:Chlorides; D009566:Nitrates; D010575:Pesticides; D012722:Sewage; D013431:Sulfates; D010100:Oxygen