00349nam a2200133 a 450000500170000002000150001708200160003210000240004824500250007226000350009730000280013263000370016063000180019720251202164218.0  a0125678509  a620.85bENV  aPurdom, Walton Pd_  aEnvironmental health  aNew YorkbAcademic Pressc1971  axiv, 584  p.b23cm.cHB  aEnvironmental health engineering  aBiotechnology