EPA's Approach to Vadose Zone Monitoring at RCRA Facilities

Abstract

The U.S. Environmental Protection Agency (EPA) recently proposed to amend federal regulations to require vadose zone monitoring at certain hazardous waste facilities. To support this proposal, EPA evaluated previous policy on vadose zone monitoring and examined advances in vadose zone monitoring technology. Changes in EPA vadose zone monitoring policy were driven by demonstrated advances in the available monitoring technology and improvements in understanding of vadose zone processes/When used under the appropriate conditions, currently available direct and indirect monitoring methods can effectively detect contamination that may leak from hazardous waste facilities into the vadose zone. Direct techniques examined include soil‐core monitoring and soil‐pore liquid monitoring. Indirect techniques examined include soil‐gas monitoring, neutron moderation, complex resistivity, ground‐penetrating radar, and electrical resistivity. Properly designed vadose zone monitoring networks can act as a complement to saturated zone monitoring networks at numerous hazardous waste facilities. At certain facilities, particularly those in arid climates where the saturated zone is relatively deep, effective vadose zone monitoring may allow a reduction in the scope of saturated zone monitoring programs.

Avaliação de contaminação de águas intersticiais e solo, devido a disposição de efluentes de curtimento em superfície - um estudo de campo

“…(Claas e Maia, 1994 Esses resíduos vêm apresentando interesse para a prática agrícola, devido ao teor de nitrogênio, fósforo, potássio, cálcio, e potencial de neutralização de acidez do solo (Fish, 1994;Neto, 1998 (Barcha, 1980 (Almeida et al, 1980;Soares et al, 1980;Barcha, '1980 (Campos, 1987), com pH entre 5,5 e 8,4, baixos teores de cloreto (< 11,2 ppm), N-NOg (< 10 ppm) e sólidos totais dissolvidos variando entre 67 e 396 mg.L-1 (Campos, '1993 (Rocha, 1986) e cidades do noroeste (Castro, 1992;Barcha, 1992 Dreiss, 1986;Szikszay et. al., 1986;Durant et. al., 1993;Zilberbrand e Gvirtzman, 1996;Alexandre, 1995;Cullen et.…”