Field Survey of Enteric Viruses In Solid Waste Landfill Leachates MARK D. SOBSEY, PHD
Abstract: Because municipal solid waste may contain fecal material from a variety of sources, there is concern that the leachate discharged from some solid waste landfills may contain enteric pathogens, including enteric viruses. In this study, 22 leachate samples from 21 different landfills in the United States and Canada were examined for enteric viruses. The sites represented a broad range of conditions for solid waste landfills and the leachate samples ranged from 10.3 to 18 liters in volume. Enteric viruses were found in only one of the 22 leachate samples examined. Two viruses,
identified as poliovirus types 1 and 3, were found in an 11.8 liter sample obtained from a site where solid waste landfill practice was deficient. The low levels of enteric viruses detected in field samples of raw leachate and the opportunities for further reductions in the virus concentration of leachates by such processes as thermal inactivation, removal by soil and dilution in ground and surface waters, suggest that leachates from properly operated solid waste landfills do not constitute an environmental or public health hazard due to enteric viruses. (Am J Public Health 68:858-864, 1978.)
Introduction
ruses in cell cultures. Using these methods, viruses have been detected only occasionally or not at all in leachates from experimentally contaminated solid waste lysimeters, apparently because viruses were retained by the solid waste and were inactivated within a relatively short time period. 1 2 4, 6-8 Information on the occurrence of enteric viruses in solid waste leachates from actual field sites has not been reported. The objective of this study was to quantitatively determine if enteric viruses are present in leachates from municipal solid waste landfills.
When water from rainfall, surface waters, ground waters, and other natural sources contacts solid waste placed in a landfill, the water becomes highly contaminated with dissolved and suspended matter which has been leached from the decomposing refuse. This leachate has many of the undesirable characteristics of a strong industrial wastewater, and its potential for contaminating ground or surface waters is a significant environmental problem associated with solid waste disposal by landfilling methods. Because municipal solid waste may contain fecal material from a number of different sources, it is possible that solid waste landfill leachate may contain enteric pathogens, including enteric viruses.Y-3 Enteric viruses have been detected in fecally contaminated articles in municipal solid
Materials and Methods
A method to detect enteric viruses in leachates has been developed which has an average virus recovery efficiency of about 40 per cent for experimentally contaminated leachates.4'5 In this method the leachate is treated with a chelating agent and an anion exchange resin to remove interferences. The viruses are then concentrated by adsorption to microporous fiberglass filters and subsequent elution in a small volume of fluid. The recovered fluid is assayed for vi-
Solid Waste Landfill Leachate Sources and Sample Points Leachate samples were obtained from a total of 21 different municipal solid waste disposal sites. These sites were selected on the basis of both geographic location and a variety of site characteristics and conditions that might possibly influence the occurrence of enteric viruses in the solid waste and the leachate. The names and locations of the sites, the characteristics and conditions used as the basis for site selection, and the specific nature of these characteristics and conditions for each site are presented in Table 1.* Twenty-two
Address reprint requests to Mark D. Sobsey, PhD, Assistant Professor of Environmental Microbiology, Dept. of Environmental Sciences and Engineering, School of Public Health, University of North Carolina, Chapel Hill, NC 27514. ESE Publ. No. 519. This paper, submitted to the Journal November 2, 1977, was revised and accepted for publication February 22, 1978.
*In general, the site conditions and characteristics shown in Table 1 are for the specific area within the total site which served as the source of the collected leachate. In cases where information could not be obtained for the specific area producing leachate, the information in the table is for the overall site. For some sites information on certain conditions or characteristics could not be obtained at all.
waste.2'3
858
AJPH September, 1978, Vol. 68, No. 9
ENTERIC VIRUSES IN LANDFILL LEACHATES
TABLE 1 -Location, Characteristics and Conditions of Municipal Solid Waste Disposal Sitesa
Site No.
AgeC Name
1 Red Hill Creek 2 Thackery
3 Beare Rd. 4 Rochester
5 Milford
Location
Hamilton, Ontario, Canada Toronto, Ontario, Canada Toronto, Ontario Canada Rochester, Minn. Milford, Conn.
6 Beacon Heights 7 Beacon Heights 8 Enfield
Beacon Falls, Conn. Beacon Falls, Conn. Enfield, Conn. 9 No. Hempsted/ Roslyn, New York 10 MorristownRoe Junction, Hamblen Co. Tenn. Lee Co., 11 Lee Co. Miss. Lafayette, 1 2 Lafayette
Imper- Refuse vious depth liner (ft.)
Refuse cover Frequency
Percent of residential refuse
Hospital waste
Sewage sludge
Septic Tank Waste
Refuse Pretreatment
Leachate Recycle
Typeb Activity
(yr.)
SLF Active
5
None
25 Dailyd
55
No
No
No
No
No
SLF Active
7
Natural
65 Daily
100
No
Noe
No
No
No
SLF Active
8
Natural
90 Daily
50
No
No
No
Yes
SLF Active
3
30 Daily
80
No
No
No
No
Test InacCell tive LF Active
2
2 ft. clay PVC
3,000 T/wk No
10 No cover
100
No
No
No
Shredded No
2
Natural
15
Periodicf
>50
No
No
No
No
No
>109 Natural
35 Periodic