An evaluation of a modified membrane filter technique for the recovery of fecal coliforms exposed to selected heavy metals

A bench study was conducted to compare two membrane filter techniques for their efficiency in recovering fecal coliforms exposed to selected heavy metals. The effects on recovery by increasing time and metal concentration were also examined. The recovery methods employed included the standard membrane filter technique (S-MF) and a modified membrane filter technique (M-MF)~ which consisted of a lactose agar overlay and a five-hour preincubation at 35 C. The heavy metals Cd, Cr, Pb, and Zn were examined, each at two concentrations, to evaluate their effect on the recovery of the I. coli test organism, after exposure for 6, 24, and 48 hours. A statistical analysis of the data found the recoveries obtained by the M-MF to be significantly greater (.0001 level) than those of the S-MF, in all cases. Time was also found to significantly effect recovery, with recoveries decreasing as time increased. A significant difference was also found between the effects of the heavy metals tested and the concentrations of metals was likewise found to significantly effect recovery, with decreased recoveries being obtained at the high concentration of each metal.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Environmental Sciences and Engineering

Department dc:contributor.department

Environmental Sciences and Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1977

Author dc:creator

• Gayle, Benjamin P.

Chair dc:contributor.committeechair

• Hoehn, Robert C.

Committee members dc:contributor.committeemember

• Boardman, Gregory D.
• King, Paul H.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-07282010-020123

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/43935