EPA has trotted out its infamous "Ohio sludge Study" as positive proof that sludge is safe to
use on farmland. It was suppose to be a 3 year study. Except the study was never
completed, but it was written up. EPA followed up with the infamous National Research
Council (NRC) Study "The Use of Reclaimed Water and Sludge in Food Crop Production".
The most alarming part of the NRC scientific study was the reference to the one limited
epidemic study on human exposure to sludge which was attributed to: Brown, R.E, and titled,
Demonstration of acceptable systems for land disposal of sewage sludge. Water
Engineering Research Lab. EPA 600/Z- 85- 062. Cincinnati, Ohio: U.S. Environmental
The Brown paper was a third party two page abstract of the actual study which noted the
World Health Organization (WHO, 1981) reported a positive association and a cycle of
infections of Salmonella from humans to sludge to animals to humans where cattle grazed
on sludge treated pastures.
Furthermore, the writers stated, "The absence of observed human or animal health effects
resulting from sludge application in this study of Ohio farms was associated with low sludge
application rates which were in accordance with Ohio and U.S. Environmental Protection
Agency guidelines. Caution should be exercised in using these data to predict health risks
associated with sludges containing higher levels of disease agents and with higher sludge
application rates and larger acreages treated per farm than used in this study."
(Municipal Sewage Sludge Application on Ohio Farms: Health Effects. Dorn, R.C., et al,
Environmental Research 38, 332- 335).
The NRC followed up the 1996 study with the 2000:
Project Title: Risks from Toxicants and Pathogens in Biosolids Applied to Land
Apparently, EPA forgot to tell the NRC it really didn't base the part 503 on a risk assessment
for toxicants. NRC claims it was going to:
1. Review the risk-assessment methods and data used to establish concentration limits for
chemical pollutants in sludge to determine whether they are the most appropriate
approaches. The committee will also consider the NRC's previous (1996) review and
determine whether that report's recommendations have been appropriately addressed.
Issues to consider include: (a) how the relevant chemical pollutants were identified; (b)
whether all relevant exposure pathways were identified; (c) whether exposure analyses,
particularly from indirect exposures, are realistic; (d) whether the default assumptions used
in the risk assessments are appropriate; and (e) whether the calculations used to set
pollutant limits are appropriate.
Interactions of pathogens and irritant chemicals in land-applied sewage sludges
Lewis DL, Gattie DK, Novak ME, Sanchez S, Pumphrey C.
US Environmental Protection Agency, National Exposure Research Laboratory, Athens,
GA, USA. LewisDaveL@aol.com
A prevalence of Staphylococcus aureus infections of the skin and respiratory tract was
found. Approximately 1 in 4 of 54 individuals were infected, including 2 mortalities
Appl Environ Microbiol. 2004 April; 70(4): 2497–2502.
Copyright © 2004, American Society for Microbiology
Fate of Salmonella enterica Serovar Typhimurium on Carrots and Radishes Grown in
Fields Treated with Contaminated Manure Composts or Irrigation Water
Salmonellae persisted for an extended period of time, with the bacteria surviving in soil
samples for 203 to 231 days, and were detected after seeds were sown for 84 and 203
days on radishes and carrots, respectively.
Three different types of compost, PM-5 (poultry manure compost), 338 (dairy cattle
manure compost), and NVIRO-4 (alkaline-pH-stabilized dairy cattle manure compost), and
irrigation water were inoculated with an avirulent strain of Salmonella enterica serovar
Typhimurium at 107 CFU g−1 and 105 CFU ml−1, respectively, to determine the
persistence of salmonellae in soils containing these composts, in irrigation water, and also
on carrots and radishes grown in these contaminated soils.
A High-Level Disinfection Standard for Land-Applied
Sewage Sludges (Biosolids)
David K. Gattie1 and David L. Lewis 2
The potential for pathogen regrowth is the downside to sewage sludge being rich in
nutrients that promote the growth of bacteria and fungi.
Exotoxins—proteins and peptides secreted into the surrounding environment by growing
cells—are produced by both gram-negative and gram-positive bacteria. They are usually
the most toxic of the two general types of bacterial toxins. Because they can retain their
toxicity at extremely high dilutions, some exotoxins, including staphylococcal enterotoxins
and shigatoxin, are used as biological warfare agents.
Unlike most exotoxins, endotoxins are heat stable even upon autoclaving (Baines
2000). They can, however, be inactivated with dry heat at > 200oC for 1 hr (Williams
Traces of endotoxins in food and water can cause headaches, fever, fatigue, and severe
gastrointestinal symptoms; however, their primary target is the lungs. In addition to the
former symptoms, inhaling endotoxin-contaminated dusts can cause acute airflow
obstruction, shock, and even death. Chronic respiratory effects can also develop
[American Conference of Government Industrial Hygienists