Do Sewage Pathogens & Contaminants Appear in Fruits and Vegetables Grown Near Septic Drainfields?
SEWAGE CONTAMINANTS in FRUIT / VEGETABLES - CONTENTS: Septic system contaminants: is it safe to eat fruits or vegetables grown over or close to septic systems? What are the risks of growing a garden, fruits, or other crops on or near septic wastewater disposal fields, drainfields, soakaway beds, or leaching trenches? How safe are the fruits of trees growing near septic soak beds or septic tanks?
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Sewage pathogens appearing in fruits and vegetables grown near septic disposal fields:
This document discusses the health hazards of consuming fruits and vegetables that may contain contaminants produced if they are grown over septic drainfields or too close to other sources of effluent from septic systems or on-site waste disposal systems
Can Sewage Pathogens & Contaminants Appear at Unsafe Levels in Fruits and Vegetables Grown Near Septic Drainfields?
We include discussion of health or other concerns with soil and groundwater contamination and with measures adopted to address these problems. Our page top photo shows the author (DJF) inspecting a vegetable farm near Frankfort, Germany in 1968.
The short answer is yes, at least some contaminants and pathogens found in sewage and sewage effluent may be present in fruits and vegetables grown on or close to septic system components that deliberately (drainfields, cesspools, drywells) or accidentally (leaky septic tanks or broken septic or sewer piping) place septic or sewage effluent in soils near plants.
But like sewage effluent, the topic is a bit murky. While some studies found dangerous levels of sewage pathogens in wastewater and in crops ground therein, and while others warn of other non-biological contaminants (chemicals, pesticides, medicines), other researches describe successful growth of some food crops in some soils where wastewater, even sewage are applied.
So unfortunately, as Mark Cramer says, " ... it depends".
On what? At least on a number of site conditions and seasonal, weather, and care or maintenance as well as design variables described here.
Studies such as the one described below did not find that all pathogens appear in fruits and vegetables grown over or near a septic drainfield. For example Staphylococcus aureum was not detected in the study below. But twenty-two other dangerous pathogens - enterobacteriaceae were indeed found.
vegetables tested in the study we discuss below were tomato, radish, cucumber,
eggplant, potato, pepper, garden pea, gourd,
zucchini, artichoke, broad bean, turnip, onion,
French bean, and lettuce.
In "Bacterial Pathogens Recovered from Vegetables Irrigated by Wastewater in Morocco", a study of the occurrence of pathogenic bacteria in vegetables irrigated by untreated wastewater, published in June 2007, Y. Karamoko et als, (quoting from the article abstract)
The authors obtained 50 vegetable samples from various regions in Morocco and examined them to determine the micro biological quality of these products. Aerobic count, coliform, enterococci, and Staphylococcus areus were evaluated. ...
The results clearly demonstrated that vegetables irrigated with untreated wastewater have a high level of microbiological contamination. ...
The large number of total microorganisms
and fecal-contamination indicators
(E. coli, coliform, and enterococci) detected in
the vegetable samples we surveyed indicates a
potential health hazard to consumers.
Also quoting from the above study,
Numerous reports have indicated that raw
vegetables may harbor potential food borne
pathogens (Beuchat, 1996). In particular,
tomatoes, cantaloupes, and sprouts have
been linked to outbreaks of salmonellosis
(Guo, Chen, Brackett, & Beuchat, 2001),
and outbreaks of illnesses caused by Escherichia
coli O157:H7 have been associated
with melon, apple eider, lettuce, and radish
sprouts (Breuer el al., 2001).
coleslaw, cabbage, potatoes, radishes, bean
sprouts, and cucumbers contaminated with
Listeria monocytogenes have been linked to
disease outbreaks (Shearer, Strapp, & Joerger,
2001), and salad vegetables also may
be contaminated with Campylobacter (Evans,
Ribeiro,& Salmon, 2003). - all of these citations can be found at our References section.
The vector of contamination of fruits and vegetables from septic effluent includes multiple paths. The authors point out that ... vegetables can become contaminated
with pathogenic organisms during growth,
harvest, post harvest handling, or distribution
(McMahon Sr Wilson, 2001). Use of
untreated wastewater in irrigation represents
an important route for transmission of
these pathogenic organisms.
So does a private septic tank and drainfield adequately treat septic effluent so that it is not a risk to crops or fruits grown nearby? Effluent discharged from a septic tank is not "untreated" - rather it is "partly treated". It is not "fully treated". We interpret this to mean that while the risk of contamination of fruits and vegetables grown over or close to a septic drainfield may be less than that found in this study, it is certainly not zero.
The level of wastewater treatment by conventional septic tanks is typically less than 20% to no more than 45%. (Jantrania). Advanced wastewater treatment systems, if the system is properly installed, designed, maintained, and is working, can treat effluent more effectively to 70%.
Jantrania points out that small wastewater treatment systems can produce good results, capable of producing exceptional quality as good as large municipal wastewater treatment systems. While Jantrania (p. 5) asserts that "Complete recycling of wastewater to drinking water standards with onsite treatment is feasible", we pose that such a level of treatment at private onsite treatment systems (residential septic tanks, drainfields, even
AEROBIC SEPTIC SYSTEMS,
Bacterial Pathogens from Septic Effluent Can Survive in Soil and Transfer through Vegetables to Humans
The authors Y. Karamoko et als, continued:
has discussed potential sources of microbial contamination
of fresh fruit and vegetables during
growth, harvest, distribution, and processing
(1992). The bacteria that the authors found on
samples belonged most frequently to the Citrobacter-
Enterobacter--Serratia group or Enterobacteriaceae.
Although usually regarded as human
pathogens, these members of Enterobacteriaceae
family have also been recognized as inhabitants
of soil and plants (Wright, Kominos, Ss Yee,
1976). Thus, vegetables may serve as a reservoir
from which the bacteria named above can colonize
and infect a susceptible host.
Our conclusion is that unless you have obtained specific and reliable tests indicating otherwise, consuming fruits or vegetables grown in soil fed by septic effluent pose a health risk.
Our OPINION is that the health risk from such foods ma be even more serious for people at extra risk due to fragile health, such as people whose immune systems are weakened or compromised, undergoing chemotherapy, for example, the elderly, infant, or people suffering from immune-related disorders. Discuss these risks with your doctor.
The Y. Karamokoet als, article discussed here is one of the most important contemporary research projects performed to study the risk of contaminants entering human food through wastewater. But interpreting the actual level of risk to a homeowner whose garden is close to or even atop a septic drainfield, and where raw sewage wastewater is not being used to directly irrigate fruits or vegetables, some important questions remain.
The questions that we pose below are intended to assist in translating the level of contamination found in the Y. Karamoko et als, study, "Bacterial Pathogens Recovered from Vegetables Irrigated by Wastewater in Morocco", Y. Karamoko, K. Ibenyassine, M. M. Ennaji, B. Anajjar, R. Ait Mhand, M. Chouibani, Journal of Environmental Health, June 2007, (wastewater irrigated plants) and the level of pathogens that might be expected to be found in fruits and vegetables grown over a common residential septic drainfield?
Question 1: How completely did the authors separate possible fruit/vegetable contaminant sources- plant root system vs. plant surfaces: contaminants arising through the soil and through a plant's root system need to be described separately from contaminants that may be lodged on the surface of a fruit or vegetable from dust, wet soil splash-up during rain, during handling?
The study cites indicates "The vegetable samples were collected in sterile polyethylene bags, and steps were taken to avoid contamination of the vegetables by soil or other contamination sources." and " Each sample was rinsed several times with sterile distilled water to eliminate the soil."
What might be unanswered is the effect of the duration of time that dust, or unsanitary water splash-up rested on plant surfaces before the plants were washed in the lab, and the extent to which pathogens may have been absorbed into the plant system through its surfaces rather than its root system.
Question 2: How do planting, soil specifics, plant root depths, septic drainfield design, high seasonal water table and type of plant affect the uptake of sewage contaminants into fruits or vegetables grown over a conventional septic drainfield compared with the uptake of sewage contaminants into these same plants when direct irrigation is performed using sewage or septic effluent?
The authors were aware of this question, as the study cites "The actual risk of disease transmission, however, is related to whether this survival time is long enough to allow transmission to a susceptible host. The crop and the field are the link between the pathogen in the wastewater and the potential for infection. The factors controlling transmission of disease are agronomic examples of such factors are the crop grown, the irrigation method used to apply wastewater, and cultural and harvesting practices. "
And "Guo and co-authors have demonstrated that soil and water are potential reservoirs from which Salmonella can contaminate tomatoes (Guo, Chen, Brackett, & Beuchat, 2002). ... That study provided evidence that Salmonellae can be transported from an inoculated nutrient solution to the hypocotyls, cotyledons, stems, and leaves of young tomato plants."
We understand the study to assert that dust and splash-up onto plant surfaces ("aerial tissues") could be a source of the pathogens found in the study, as well as roots "tissues in contact with inoculated soil".
This combination of pathogen sources may make it more difficult to translate the results of this study to a level of risk for plants grown over septic drainfields, systems where effluent is not being applied directly to the surface of soils but rather is being distributed underground.
Question 3: What assays were made of the level of contaminants in the irrigating sewage or septic effluent that was used to irrigate the studied fruits and vegetables?
We did not find this information included in the study except for a general description of the types of contaminants found in wastewater used for irrigation in many countries.
Question 4: What differences should we expect to find between the level of contaminants in the irrigating sewage or septic effluent used in the areas studied compared with the level of contaminants in private onsite septic system effluent flowing into a septic drainfield?
OPINION: This is the chief question that needs to be answered in extending the results of this important study to the question of the level of pathogens that may be found in garden vegetables or fruits planted over or close to a conventional septic system drainfield in which effluent is disposed-of entirely below ground.
OPINION: A second level of risk is likely to be found in alternative septic system designs (aerobic or ATU systems used for example in the Southwestern U.S.). Although aerobic ATUs achieve a higher level of treatment, in some private septic system designs the effluent from those systems is dispersed to the ground surface using sprays. The benefit of higher level of treatment of wastewater may be offset by its surface application if property owners grow edible foods nearby.
Factors Affecting Risk of Pathogenic Contamination of Vegetables or Fruits Grown over a Septic Drainfield
At Gardens Near Septics we stated that planting a fruit or vegetable garden over or near septic system components raises some important questions:
Will there be pathogenic or chemical contamination of the soil (bacteria, viruses, cleaners) below the garden?
Will septic system pathogens enter in or contaminate fruits or vegetables planted over or near the septic system?
Will chemicals or salts passing through the septic system harm nearby plants?
Will the garden planting itself harm the septic system in some way?
It seems likely that the following variables will affect the level of contaminants picked up by vegetables or fruits grown on or over private septic drainfields and effluent disposal systems:
The presence/absence of particular contaminants disposed-of into a particular onsite wastewater treatment unit, such as high levels of antibiotics, chemicals, or unusual pathogens - this is an unknown
Condition of the specific onsite treatment system or septic system: an older septic drainfield that is no longer working, pushing sewage effluent to or close to the yard surface, is at greater risk of contaminating not only plants growing over the drainfield, but any plantings that are down-slope from that area. Therefore original septic system design, septic system maintenance (SEPTIC TANK PUMPING SCHEDULE),
The level of treatment of wastewater achieved by the septic tank or treatment unit - reasonable for conventional septic tanks is to presume no greater than 45% treatment in the tank, with an unknown level of additional treatment within the soils where wastewater is being discharged
The rate of discharge of wastewater into the system: a high-use septic system, possibly even used beyond its design point, can push wastewater into the septic tank or treatment system faster than treatment can take place, resulting in discharge of un-treated effluent or very limited treatment of effluent, before it is discharged into the absorption system, thus increasing the level of pathogens in the soil
Soil conditions and design of the wastewater absorption system: the distance between the bottom of the wastewater trenches of a drainfield and the seasonal high water table, soil percolation rates, soil chemistry, depth at which the wastewater is discharged (deeper means less oxygen means less aerobic bacterial action), age and condition of the system (is it exposed to periodic flooding?) and similar factors will affect not only the level of treatment achieved in the soils but the distance between septic effluent and the root system of the plants that may be present nearby or above.
Type, location, and specific species of plants near the septic system: plant systems vary by root depth, root characteristics, and other factors that are likely to affect the uptake of pathogens into the plant systems.
At Gardens Near Septics we provide details such as plant type, root system type, and plant location and we offer some opinion about those effects on plant contamination by sewage pathogens.
Seasonal changes in soil conditions, level of septic system usage, effluent transpiration rate, and similar factors.
Septic "Treatment Chemicals" may Also be a Hazard to Nearby Fruits & Vegetables
OPINION: At ROOT KILLERS in SEWER LINES or SEPTIC PIPES we discuss using chemicals to try to "clear" septic system piping and drainfields. These products include a range of chemicals whose product-description ranges from "safe and harmless" to "toxic -keep out of reach of children".
We have not yet found studies of toxic chemicals picked up by fruits and vegetables grown near septic systems from chemical treatment sources. Contact Us if you have information.
OPINION: A second category of possible "chemical " contaminants from sewage includes heavy metals that may be present in sewage or septic effluent.
What About Fruits & Vegetables Grown Near the Septic Tank Itself?
Question: what about medical chemicals that enter the septic tank and then the drainfield area?
(June 27, 2012) Anonymous said:
We have an old cerment drain septic tank ( about 40 years ols ) In haqve been having chemo treaztment every 2 weeks for the past 6 monrh. Would this cause damage to system
Anon, thanks for the interesting question; we have found and provide citations that indicate that high levels of antibiotics in a septic tank can kill off bacteria enough to interfere with the tank's normal operation; but I don't know the effects of the chemicals in chemotherapy on a septic system.
We also don't know what happens to those chemicals when they pass out of the septic tank and into the drainfield. Normally I'd expect that any chemicals that do not deteriorate in the presence of soil bacteria and the limited oxygen there migrate down to local waterways or ultimately to the aquifer, presumably in quite diluted form. But we don't know what happens if a septic tank or drainfield contain high levels of chemicals and then are flooded.
If you are just one occupant in the household I suspect that the effects are minimal; if you're worried about it nonetheless, I recommend having the septic tank pumped at twice the normal pumping frequency for the tank size and number of users. Let's hope your treatment is finished soon and all related worries are done and over.
Question:If my avocado and mango trees are planted near, within three meters of my septic tank, are they safe to eat? -- Cheryl Sweetland
Answer: OPINION: Well, the answer is a definite "maybe". Or as ASHI Educator Mark Cramer says, "It depends."
In theory, a septic tank that is working correctly never overflows or floods. Sewage and septic effluent stay safely inside the tank and effluent flows out of the septic tank through solid piping (not perforated piping) to a drainfield or to a distribution box that then connects to the drainfield.
If your trees are a safe distance from the drainfield and if the septic tank is not leaky, and if no one spills sewage all around the tank during pumping, your mangos and avocados are probably fine to eat. at SEPTIC SYSTEMS, PLANTS OVER we discuss issues of planting anything over or near septic system components. If your trees are close to the septic tank there are two other risks:
The tree roots may invade the septic tank or piping, leading to blockage or damage
The tree roots may ultimately have to be cut to access or clean the septic tank, leading to a dead or sick tree.
If your septic tank is home-made or "site built" or if it is a cesspool, it is much more likely that tree roots will invade and damage the system and that fruit on those trees may be contaminated as well.
If you don't know where the drainfield is actually located on your property, it would be smart to find it. See SEPTIC DRAINFIELD LOCATION.
Safety of Fruits Grown on Trees Near Septic Tanks or Septic Drainfields
Reader Comment: A garden over a drainfield does not present the same risks as using sewage directly on crops - tree crops may be ok
I recently found your site and find it very useful. Being very interested and reasonably well educated in wastewater and reuse I found your review of the septic system and gardens interesting (I like fining new articles) but perhaps too conservative and too have missed an important point.
The Morocco paper refers to harvest of vegetables with untreated wastewater as you mention but most importantly the wastewater is applied at the soil surface. This is very different from growing a garden on top of a drainfield. In a well operating drainfield (i.e. no surfacing sewage) the septic tank effluent is well treated and will only be in contact with the plant roots.
A review of the literature shows that this mechanism of transport for pathogens into healthy plants is unlikely, particularly in tree crops.
Peter Burgoon, PhD, P.E.
Water Quality Engineering, Inc.
Editor's note, quoting from WQE's website: Water Quality Engineering, Inc (WQE) specializes in evaluation and design of processes that impact water quality in the rural and suburban landscape. Water Quality Engineering, Inc (WQE) specializes in evaluation and design of processes that impact water quality in the rural and suburban landscape.
Reply: Ok to grow food crops over a septic drainfield? It depends ...
Your angrily- put point about the lower risk of sewage pathogens in tree crops is nevertheless well taken, though that too may need some clarification. Your demand for a "concrete answer" without, as I would put it, any qualifications, is understandable (as simplistic answers are easier to digest you may be frustrated) but still the demand for a single "yes or no" answer is ill-advised.
For example in the case of some fruit crops (mangos, papaya) grown in Mexico and Central and South America there has long been a concern for and history of septic pathogens in [or on] those foods.
Testing those fruits for coliform or other contaminants is tricky because often they are harvested, transported, stored, and sold under dusty conditions during which contaminants may settle onto the skin or surface of the fruit even though contemporary growing conditions themselves may not be a source of contamination.
Certainly out of the U.S. it is good practice (and a commonly followed procedure) to wash all fruits and vegetables in a suitable disinfectant (we use SinBac®) before consuming them. This disinfection step removes contaminated surface dust or bacteria that may have been placed thereon by handling. [We discuss SinBac
at CHLORINE DISINFECTANT for Drinking Water]
The topic of what can be grown over a septic drainfield continues to interest many of our readers. My OPINION, for which I'd appreciate argument from you, is ... it depends.
Reader Comment: so can fruit trees filter toxins or not? Just tell me "yes" or "no" !
(Mar 24, 2012) kenboe said:
After reading this I have seen no scientific claim that eating fruit from a tree whom's roots draw water from a septic field directly will transmit chemical, bacterial, or viral toxins to the fruit. You obfuscate like a lawyer around the issue without courage or directness. You clearly state that your studies were on vegetables that grow low to the ground in irrigated soil which is a whole different kind of exposure to root-only exposure of a tree.
The question is simple and direct. Are fruit trees capable of filtering toxins? What are the specifics?
Another website claimed that toxins will settle in the skin of citrus, not the pulp. Is this a folk tale? Let's get some real answers here regarding the tree's ability to filter water from root, to trunk, to branch, to fruit, and what parts of the fruit. In some other plants, leaves are poisonous but fruit or stalk is not, and butterflies also put toxins in their wings. I don't want an answer from a babysitter. I want a concrete answer without concern for whether or not some loon is going to sue you. If you worry about that, quit writing altogether.
Mr. /Ms. kenboe:
First please check the discussion immediatlely preceding your question.
I too find more interesting and helpful information on reading the studies by experts than reading what are more characterized as opinion. Considering the research behind this article and the extensive citations of expert, opinion and scholarly research deserve to be distinguished.
You refer to "your studies" but in fact they are not mine nor any other site editor. Best to take a look at the authors, their qualifications, what they studied and what they concluded. You might also want to take note throughout this article series that we explain the reasoning behind some of the more cautious remarks.
You might want to read in recent work by Leff (2013) who point out that the actual contaminants that are found in fruits and vegetables can vary widely by the particular fruit or vegetable species as well as by growing conditions. So an honest, cogent, informed answer to your "just say yes or no" question, is unfortunately "it depends." That's the real answer, whether it's a comfortable one or not.
For folks who prefer a bottom line and who don't want to read the article itself, an abstract for this article is included in our citations above.
Simple answers may be appealing and you may demand a simple yes or no answer to food crop contamination, but, simplistic answers are often dangerous as well as wrong.
A root crop, ground crop, or tree crop that is perfectly sanitary in a location in one year might be highly contaminated in another year when weather conditions change. Local area flooding, septic drainfield failures, blocked pipes, overflowing septic tanks, a change in septic tank maintenance, even some fool driving a heavy machine over a drainfield so that pipes are crushed or soil is compacted or fill is added, can significantly change where sewage effluent appears and how it affects (or doesn't ) nearby crops.
Risk of drainfield damage from gardening activities
some drainfield overgrowth can interfere with transpiration
driving garden tractors etc over a drainfield can ruin it
Risk of pathogens entering food crops grown over or near septic drainfields or soakaway beds?
the degree to which pathogens may enter food crops grown over a drainfield probably depends on factors such as the crop genera/species, its root properties (depth, length, absorption rate, probably other things I don't know about), and, importantly, the
condition of the drainfield as well.
OPINION: we estimate that a significant portion of onsite wastewater disposal systems are not effectively treating septic effluent well before the property owner recognizes a failure (such as wet areas or odors).
Particularly this seems the case with some aerobic systems [a high failure rate has been reported, usually due to lack of proper maintenance] and in particular, aerobic septic systems that that use above ground spray to dispose of effluent pose health risks to nearby crops; also cesspools, and septic systems with conventional drainfields in wet or episodically flooded areas are very often not treating wastewater pathogens nor heavy metals.
By no means do we want our content to be inappropriately scary or to give improper guidance about growing crops on or near drainfields; We've had difficulty finding expert authoritative papers and articles on the topic, so we welcome any further comment or citations you can offer.
Bacteriological test suggestions for crops grown close to onsite wastewater systems
For Summer (discussion above), if with all of this arm waving and wailing you want to go ahead with some care, you know some of the worries to attend. It would be useful to actually test some of the produce grown in the vegetable garden you describe for soil & sewage bacteria on both the surface and inside.
It is normal to find bactria in any outdoor soil sample. Your local health department or testing lab can suggest simple procedures for collecting surface and perhaps shallow sub-surface soil or water samples to look for unacceptable levels of pathogens or eColi or other sewage contaminant indicators.
Testing for other potential contaminants such as chemicals that could be present can be more costly and wasteful unless some research suggests specific test targets based on other information about the building occupants, site, nearby sites, history of use of chemicals such as pesticides etc.
4/27/14 Mark said:
How can I get my vegetable and fruit produce professionally tested to ascertain contamination from sewage pathogens?
Mark a microbiology test lab, the same folks who do water testing, sewage contamination testing, can test other materials for pathogens. Be sure to discuss with local labs in your area just what is their normal scope of work and expertise. Some labs drastically limit their practice.
To better understand the concerns around pathogens found in fruits & vegetables and how they vary by type of fruit/vegetable as well as growing conditions, I found the following article quite pertinent. Be sure to read the abstract included in our citations even if you don't choose to read the whole article.
Leff, Jonathan W., and Noah Fierer. "Bacterial communities associated with the surfaces of fresh fruits and vegetables." PloS one 8, no. 3 (2013): e59310.
My point is that when we ask a lab to test for pathogenic contamination of fruits and vegetables we need to
1. Ignore the folks who argue that such foodstuffs are not at risk and so testing is always unnecessary as well the folks who argue that contamination is so certain that testing is pointless. We are forced by reality to ask the food crop contamination question with more thoughtfulness: what is the crop, where was it grown, when, under what conditions, and exposed to what environment.
2. Ask the microbiology lab what they will test-for, as we might need to look for different pathogens on different foods. I worry that some prior research, as I've found in the area of mold contamination, seriously misreports the presence or absence of hazards because the investigator didn't look thoroughly or used an unreliable test method.
Like bird watching, how do you spot a Quetzal? Well you have to look where they live (in certain areas of Costa Rica) and it helps to know what they eat (little avocados) and when they will be there eating (early morning). Another bird watcher might say there are no Quetzals there, even looking in the same spot, but at the wrong time of day.
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Quoting from the company's website: Water Quality Engineering, Inc (WQE) specializes in evaluation and design of processes that impact water quality in the rural and suburban landscape. We are a small streamlined company that teams with other experts around the region to complete projects as cost effectively and timely as possible. Our goal is quality work, service, and cost savings to our clients.
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We are experienced and successful in grant procurement for organizations who need assistance in funds for planning, engineering, and nonpoint source pollution studies and BMP implementation. WQE provides services to municipalities, industries, irrigation districts and individuals throughout the Northwest.
"Bacterial Pathogens Recovered from Vegetables Irrigated by Wastewater in Morocco", Y. Karamoko, K. Ibenyassine, M. M. Ennaji, B. Anajjar, R. Ait Mhand, M. Chouibani, Journal of Environmental Health, June 2007.
Abstract: The authors obtained 50 vegetable samples from various regions in Morocco and examined them to determine the micro biological quality of these products. Aerobic count, coliform, enterococci, and Staphylococcus areus were evaluated. This analysis revealed high levels of enterococci, fecal coliforms, and total coliforms. No coagulase-positive Staphylococcus aureas was detected in any of the samples analyzed. Biochemical identification of Enterobacteriaceae showed the presence of Citrobacter freundii (28 percent), Enterobacter cloacae (27 percent), Escherichia coli (16 percent), Enterobacter sakazakii (12 percent), Klebsiella pneamoniae (17 percent), Serratia liquefaciens (11 percent), and Salmonella arizonae (0.7 percent). The results clearly demonstrate that vegetables irrigated with untreated wastewater have a high level of microbiological contamination. Consequently, these vegetables may be a threat for the Moroccan consumer and may be considered a serious risk to Moroccan public health. ABSTRACT FROM AUTHOR Copyright of Journal of Environmental Health is the property of National Environmental Health Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. Contact Us to request a copy of this article stored as BacterialPathogens.pdf if you have difficulty obtaining a copy of this full article for private use. at BACTERIAL PATHOGENS in FRUIT & VEGETABLES is a slightly-rough online copy.
Beuchat, L.R. (1996). Pathogenic microorganisms associated with
fresh produce. Journal of Food Protection, 59(2), 204-216.
Evans, M.R., Ribiero, CD., & Salmon, R.L. (2003). Hazards of
healthy Living: Boiled water and salad vegetables as risk Factors
For Campylobacter infection. Emerging Infectious Disease, 9(10),
Guo, X., Chen, j . , Brackett, R.E., & Beuchat. LR. (2001). Survival of
Saimonellae on and in tomato plants From the time of inoculation at
flowering and early stages of fruit development through fruit ripening.
Applied and Environmental Microbiology, 67(10), 4760-4764
Madden, J.M. (1992). Microbial pathogens in fresh produce—The
regulatory perspective. Journal of Food Protection, 55, 821-823.
Shearer, A.E., Strapp, CM., & Joerger, R.D. (2001). Evaluation of
polymerase chain reaction-based system for detection of Salmonella
enteritidis, Escherichia coli O157:H7, Listeria spp., and Listeria monocytogenes on Fresh Fruit and vegetables. Journal of Food
Protection, 64(6), 788-795.
"Septic Tank/Drainfield System Fact Sheet", Utah Department of Environmental Quality, Division of Drinking Water, Source Protection Program - (801) 536-4200 Division of Water Quality - (801) 538-6146 Sonja Wallace, Pollution Prevention Coordinator - (801) 536-4477 Environmental Hotline - 1-800-458-0145 - Original source: http://www.drinkingwater.utah.gov/documents/spec_services/pollution_prevention_septic_tanks.pdf
New York State Wastewater Treatment Standards - Individual Household Systems, Appendix 75-A (1990),
Public Health Law 201(1)(1).
treatment systems, Bennette D. Burks & Mary Margaret Minnis. Textbook and reference manual on all aspects of onsite treatment. This is one of the best books we've reviewed on the subject, with an excellent balance of clear simple explanation and solid engineering. Topics: Soil & Site Selection, Hydraulics, System Selection & Design, Wastewater Biology, History & Mythology of Onsite Wastewater
Treatment. $49.95, Hogarth House, Ltd., 800-993-2665 x327 order a copy from the InspectApedia bookstore (Amazon.com) or order by telephone 800 -993-2665 x327 (Univ. Wisc. Bookstore)
Thanks to reader Cheryl Sweetland for email discussion of planting fruit trees (avocado & mango trees) near a septic tank 07/13/2010
"Bacteria in Drinking Water" - "Chlorine," Karen Mancl, water quality specialist, Agricultural Engineering, Ohio State University Extension. Mancl explains factors affecting the effectiveness of chlorine in water as a means to destroy bacteria and other microorganisms. OSU reports as follows:
Chlorine kills bacteria, including disease-causing organisms and the nuisance organism, iron bacteria. However, low levels of chlorine, normally used to disinfect water, are not an effective treatment for giardia cysts. A chlorine level of over 10 mg/1 must be maintained for at least 30 minutes to kill giardia cysts. -- http://ohioline.osu.edu/b795/index.html is the front page of this bulletin.
Giardia exposure limits for drinking water: see www.mass.gov/dep/water/drinking/standards/giardia.htm is the current regulatory exposure limit (your minimum target for sterilization)
1-Bromo-3-chloro-5,5-dimethylhydantoin (C5H6BrClN2O2) is produced world-wide and is also used in cleaners and bathroom disinfectants and deodorizers. Here is an example MSDS for this product, provided by Leisure Time
Principles and Practice of Disinfection, Preservation and Sterilization (Hardcover)
by A. D. Russell (Editor), W. B. Hugo (Editor), G. A. J. Ayliffe (Editor), Blackwell Science, 2004. ISBN-10: 1405101997, ISBN-13: 978-1405101998.
Handbook of Disinfectants and Antiseptics, Joseph M. Ascenzi (Editor), CRC, 1995, ISBN-10: 0824795245 ISBN-13: 978-0824795245 "The evaluation of chemical germicides predates the golden age of microbiology..." -
This well-focused, up-to-date reference details the current medical uses of antiseptics and disinfectants -- particularly in the control of hospital-acquired infections -- presenting methods for evaluating products to obtain regulatory approval and examining chemical, physical, and microbiological properties as well as the toxicology of the most widely used commercial chemicals.
Amahmid, O., Asmama, S., & Bouhoum, K. (1999). The effect of waste water reuse in irrigation on the contamination level of food crops by Giardia cysts and Ascaris eggs. International Journal of Food Microbiology, 49(1-2), 19-26.
Barak, J.D., Whitehand, L.C., & Charkowski, A.O. (2002). Differences in attachment of Salmonella enterica serovars and Escherichia coli O157:H7 to alfalfa sprouts. Applied and Environmental Microbiology, 68(10), 4758-4763.
Beuchat, L.R. (1996). Pathogenic microorganisms associated with fresh produce. Journal of Food Protection, 59(2), 204-216.
Castro-Rosas, J., & Escartin, E.F. (2000). Survival and growth of Vibrio cholerae O1, Salmonella typhi, and Escherichia coli O157:H7 in alfalfa sprouts. Journal of Food Science, 65(1), 162-165.
Charkowski, A.O., Barak, J.D., Sarreal, C.Z., & Mandrell, R.E. (2002). Growth and colonization patterns of Salmonella enterica and Escherichia coli O157:H7 on alfalfa sprouts and the effects of sprouting temperature, iinoculum /in·oc·u·lum/ (-ok´u-lum) pl. inoc´ula material used in inoculation.
Evans, M.R., Ribeiro, C.D., & Salmon, R.L. (2003). Hazards of healthy living: Bottled water and salad vegetables as risk factors for Campylobacter infection. Emerging Infectious Disease, 9(10), 1219-1225.
Frost, J.A., McEvoy, M.B., Bentley, C.A., Andersson, Y., & Rowe, B. (1995). An outbreak of Shigella sonnei infection associated with consumption of iceberg. Emerging Infectious Disease, 1(1), 26-28.
Guo, X., Chen, J., Brackett, R.E., & Beuchat, L.R. (2001). Survival of Salmonellae on and in tomato plants from the time of inoculation at flowering and early stages of fruit development through fruit ripening,
said of meat. See curing. . Applied and Environmental Microbiology, 67(10), 4760-4764.
Guo, X., Chen, J., Brackett, R.E., & Beuchat, L.R. (2002). Survival of Salmonellae on tomatoes stored at high relative humidity, in soil, and on tomatoes in contact with soil. Journal of Food Protection, 65(2), 274-279.
Guo, X., Iersel, M.W.V., Chen, J., Brackett, R.E., & Beuchat, L.R. (2002). Evidence of association of salmonellae with tomato plants grown hydroponically in inoculated nutrient solution. Applied and Environmental Microbiology, 68(7), 3639-3643.
Itoh, Y., Sugita-Konishi, Y., Kasuga, E, Iwaki, M., Hara-Kudo, Y., Saito, N., Noguchi, Y, Konuma, H., & Kumagai, S. (1998) Enterohemorrhagic Escherichia coli enterohemorrhagic Escherichia EHEC Any of the E coli serotypes–eg O29, O39, O145 that produces shiga-like toxins, causing bloody inflammatory diarrhea, evoking a HUS. See Escherichia coli O157:H7, Hemolytic uremic syndrome. O157:H7 present in radish sprouts. Applied and Environmental Microbiology, 64(4), 1532-1535.
Madden, J.M. (1992). Microbial pathogens in fresh produce--The regulatory perspective. Journal of Food Protection, 55, 821-823.
McMahon, M.A.S., & Wilson, I.G. (2001). The occurrence of enteric pathogens and Aeromonas species in organic vegetables. International Journal of Food Microbiology, 70(1-2),155-162.
Puohiniemi, R., Heiskanen, T., & Siitonen, A. (1997). Molecular epidemiology of two international sprout-borne Salmonella outbreaks. Journal of Clinical Microbiology
. 35(10), 2487-2491.
Shearer, A.E., Strapp, C.M., & Joerger, R.D. (2001). Evaluation of polymerase chain reaction-based system for detection of Salmonella enteritidis, Escherichia coli O157:H7, Listeria spp., and Listeria monocytogenes on fresh fruit and vegetables. Journal of Food Protection, 64(6), 788-795.
Takeuchi, K., Hassan, A.N., & Frank, J.F. (2001). Penetration of Escherichia coli O157:H7 into lettuce as influenced by modified atmosphere and temperature. Journal of Food Protection, 64(11), 1820-1823.
Wright, C., Kominos, S.D., & Yee, R.B. (1976). Enterobacteriaceae and Pseudomonas aeruginosa recovered from vegetable salads. Applied and Environmental Microbiology, 31(3), 453-454.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Advanced Onsite Wastewater Systems Technologies, Anish R. Jantrania, Mark A. Gross. Anish Jantrania, Ph.D., P.E., M.B.A., is a Consulting Engineer, in Mechanicsville VA, 804-550-0389 (2006). Outstanding technical reference especially on alternative septic system design alternatives. Written for designers and engineers, this book is not at all easy going for homeowners but is a text I recommend for professionals--DF.
Builder's Guide to Wells and Septic Systems, Woodson, R. Dodge: $ 24.95; MCGRAW HILL B; TP;
Quoting from Amazon's description: For the homebuilder, one mistake in estimating or installing wells and septic systems can cost thousands of dollars. This comprehensive guide filled with case studies can prevent that. Master plumber R. Dodge Woodson packs this reader-friendly guide with guidance and information, including details on new techniques and materials that can economize and expedite jobs and advice on how to avoid mistakes in both estimating and construction. Chapters cover virtually every aspect of wells and septic systems, including on-site evaluations; site limitations; bidding; soil studies, septic designs, and code-related issues; drilled and dug wells, gravel and pipe, chamber-type, and gravity septic systems; pump stations; common problems with well installation; and remedies for poor septic situations. Woodson also discusses ways to increase profits by avoiding cost overruns.
Country Plumbing: Living with a Septic System, Hartigan, Gerry: $ 9.95; ALAN C HOOD & TP;
Quoting an Amazon reviewer's comment, with which we agree--DF:This book is informative as far as it goes and might be most useful for someone with an older system. But it was written in the early 1980s. A lot has changed since then. In particular, the book doesn't cover any of the newer systems that are used more and more nowadays in some parts of the country -- sand mounds, aeration systems, lagoons, etc.
Onsite Wastewater Disposal Books
Onsite Wastewater Disposal, R. J. Perkins;
Quoting from Amazon: This practical book, co-published with the National Environmental Health Association,
describes the step-by-step procedures needed to avoid common pitfalls in septic system technology.
Valuable in matching the septic system to the site-specific conditions, this useful book will help you install a reliable system in
both suitable and difficult environments. Septic tank installers, planners, state and local regulators, civil and sanitary engineers,
consulting engineers, architects, homeowners, academics, and land developers will find this publication valuable.
Onsite Wastewater Treatment Systems, Bennette D. Burks, Mary Margaret Minnis, Hogarth House 1994 - one of the best septic system books around, suffering a bit from small fonts and a weak index. While it contains some material more technical than needed by homeowners, Burks/Minnis book on onsite wastewater treatment systems a very useful reference for both property owners and septic system designers.
Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf
Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000 $14.95 U.S. - easy to understand, well illustrated, one of the best practical references around on septic design basics including some advanced systems; a little short on safety and maintenance. Both new and used (low priced copies are available, and we think the authors are working on an updated edition--DF.
Quoting from one of several Amazon reviews: The basics of septic systems, from underground systems and failures to what the owner can do to promote and maintain a healthy system, is revealed in an excellent guide essential for any who reside on a septic system. Rural residents receive a primer on not only the basics; but how to conduct period inspections and what to do when things go wrong. History also figures into the fine coverage.
Grass is Always Greener Over the Septic Tank, Bombeck, Erma: $ 5.99; FAWCETT; MM;
This septic system classic whose title helps avoid intimidating readers new to septic systems, is available new or used at very low prices.
It's more entertainment than a serious "how to" book on septic systems design, maintenance, or repair. Not recommended -- DF.
US EPA Onsite Wastewater Treatment Systems Manual Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm
Water Wells and Septic Systems Handbook, R. Dodge Woodson. This book is in the upper price range, but is worth the cost for serious septic installers and designers.
Quoting Amazon: Each year, thousands upon thousands of Americans install water wells and septic systems on their properties. But with a maze of codes governing their use along with a host of design requirements that ensure their functionality where can someone turn for comprehensive, one-stop guidance? Enter the Water Wells and Septic Systems Handbook from McGraw-Hill.
Written in language any property owner can understand yet detailed enough for professionals and technical students this easy-to-use volume delivers the latest techniques and code requirements for designing, building, rehabilitating, and maintaining private water wells and septic systems. Bolstered by a wealth of informative charts, tables, and illustrations, this book delivers:
* Current construction, maintenance, and repair methods
* New International Private Sewage Disposal Code
* Up-to-date standards from the American Water Works Association
Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF.
Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: email@example.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides extensive home inspection education and report writing material.
The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors. Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
TECHNICAL REFERENCE GUIDE to manufacturer's model and serial number information for heating and cooling equipment, useful for determining the age of heating boilers, furnaces, water heaters is provided by Carson Dunlop, Associates, Toronto - Carson Dunlop Weldon & Associates Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones