005290000a22001810004500003000900000005001700009100002000026710004200046710004200088245002600130264006100156300000900217041000800226490004200234650001600276650004400292040001100336PH-MaWHO20241108112553.0  aWheal, Caroline  aUnited Nations Environment Programme.  aGlobal Environment Monitoring System.  aFreshwater pollution.  aNairobi : bUnited Nations Environment Programme,c1991.  a36p.  aeng  aUNEP/GEMS environment library ; no.6.  aFresh water  aWater pollutionxPrevention and control  aWHOLIS