FEED

This is the most effective point of addition. Many farms have eliminated most of their odor and
realized greater animal health, welfare, and production by feeding between ˝ to 2% of the total
ration on a weight basis of BRZ™. A 14 x 40 or a -40 mesh product should be fed in mash or
a -100 mesh should be used to pelletize supplements.

BEDDING AREA

A thin layer should be applied to the bedding area or to the area that receives the manure each time
it is cleaned out

COMPOST OR DRY STACKED MANURE

The compost or dry stacked manure should be “top dressed” with a thin layer of BRZ™ after it is turned or after the addition of a new layer of manure. Alternatively, a layer of BRZ should be placed
in the area of the barn receiving the fresh manure. Composting is an important process that
(1) converts organically bound nitrogen that is not plant accessible to ammonium hydroxide, ammonium nitrate, and ammonia that then are plant accessible, (2) kills the pathogens, (3) reduces
or eliminates the odor, (4) dries the manure, (5) reduces the flies, and (6) kills weed seeds. Composting should be conducted “in vessel” to prevent groundwater and air pollution. Wash down operations are no longer environmentally acceptable due to groundwater pollution of nitrates,
nitrites, and hydrogen sulfide.
 

• Mineral:         Consists of a volcanic mineral called "clinoptilolite".

• Size:               14 x 40, 40 x 100,-100, -40 mesh

• GRAS:            Classified as “GRAS” (generally regarded as safe)
                          under21 CFR Part 182.2729, 40 CFR Part 180.1001

• CEC:               Cation exchange capacity (CEC) 160 to 180 meg/100 gram (as ammonia, N)

• Color:             Pale green when dry, dark green when wet

• Moisture:       Holds up to 55% of its weight in water

• Surface Area:            High surface area, 24.9 square meters/gram

• Weight:           55 pounds per cubic foot

• Potassium:     Contains 3.47%

• Calcium:         Contains 1.6%

• Sodium:          <0.5% (none water soluble)

• Hydrophilic:

According to Lobo (1999, Feed Management, V.50, No.8, p.16-17) in 1998 layers and broilers consumed 44 million tons of feed in the United States.

• REDUCES DIARRHEA

• MYCO-TOXIN BINDER

Zeolites are recognized as effective myco-toxin binders in many countries but not in the United States.

• INCREASES SOLUBILITY OF PHOSPHATE IN BIRDS

The zeolite exchanges the calcium from dicalcium phosphate and makes the phosphate more soluble and better utilized by the bird for bones. The dicalcium phosphate in the feed may be reduced by 50% after testing.

• INCREASED NUMBER OF GRADEABLE EGGS

• REDUCES FOOT PAD BURNS FROM PHOSPHOROUS

• LOWERS MORTALITY

• INCREASES FOOD EFFECIENCY VALUES/LOWER FEED CONVERSION RATES

• INCREASED SHELL THICKENESS

• LESSER OR NO ANTIBIOTICS

• INCREASED PELLET DURABILITY FOR FEEDS

• FLOW AGENT/ANTI CAKING AGENT

• INCREASED PRODUCTION FROM HEALTHIER BIRDS

• INCREASED NITROGEN CONTENT OF MANURE AND COMPOST

BRZ™ increases and fixes the nitrogen in the manure and compost so that it is plant accessible but not water-soluble. It stops the gassing of the nitrogen as ammonia. Good chicken compost should sell for $75.00 to $90.00 per ton. Many of the areas that have been repeatedly fertilized with chicken manure now have phosphate problems. This is a result of not enough nitrogen to balance the plant uptake of the phosphorous. The problem can be solved by increasing the nitrogen, by the addition of phytase to the feed, and by feeding BRZ to solublize the phosphate in the bird.

• BRZ™ ADDS VALUE TO MANURE AND COMPOST

The introduction of BRZ™ with the manure or compost to the soil has the benefit of increasing water retention, holding the nitrogen and other nutrients in the growth zone, provides a medium for the future capture of nitrogen,  increases the ion exchange capacity of the soil, provides potassium and calcium, and enhances infiltration and aeration of the soil. BRZ™ is a value added soil amendment that should be advertised as such.

• ODOR CONTROL

Reduces the ammonia gas and odor in the coop and manure storage and compost areas.

• FLY CONTROL

Reduced ammonia gas and increased moisture absorption helps control flies.

• INCREASED ANIMAL WELFARE

Greater animal health creates better animal welfare, better products, greater production, and less usage
of antibiotics and medicines that may have lasting adverse effects to the human population.

• GROUNDWATER POLLUTION CONTROL

Fixing the nitrogen and various heavy metals reduces the pollution of the groundwater with nitrates and
nitrites.

• RECYCLE EGG WASH WATER

Egg wash water can be recycled after filtration through a bed of zeolite granules to remove suspended solids and bacteria (e.g. E. Coli, etc.).

Using clinoptilolite from the Itaya r-nine, Yamagata Prefecture, and mondenite from Karawago, Miyagi
Prefecture, Onagi (67) found that Leghorn chickens required less food and water and still gained as much
weight in a 2-week trial as birds receiving a control diet. Feed efficiency values (FEV)l were markedly
higher at all levels of zeolite substitution; feedstuffs containing 10 percent zeolite gave rise to efficiencies
more than 20 percent greater than those of normal rations (table 4). Adverse effects on the health or
vitality of the birds were not noted, and the droppings of groups receiving zeolite diets contained up to 25
percent less moisture than those of control groups, after a 1 Weight gain/feed intake, excluding zeolite,
12-day drying period, making them considerably easier to hand1e. Broiler chickens fed a diet of 5 percent c1inoptilite from the Hector, CA, deposit gained slight1y 1ess weight over a 2-month period than birds receiving
a normal diet, but average FEVS were noticeably higher (table 5) (6). Perhaps of greater significance is the fact
that none of the 48 test birds on the zeolite diet died during the experiment, while 3 on the control diet and 2 on
the control diet supplemented with antibiotics succumbed. In addition to an apparent feed-efficiency increase
of 4 to 5 percent, the presence of zeolite in the diet appears to have had a favorable effect on the mortality
of the birds. Hayhurst and Willard (27) confirmed many of Onagi’s observations and reported small increases
in FEV for Leghorn roosters over a 40-day period, especially during the first 10 days. The birds were fed a
diet containing 7.5 percent clinoptilolite crushed and mixed directly with the normal rations. Feces were
noticeably dryer and less odoriferous. Unfortunately, only 17 birds were used in the study and extensive
statistical evaluation of the results could not be made.

Table 4.—Caloric Efficiencies of Zeolite Supplements in poultry Feedinga

a Onagi (1966) Tests carried out on 48-day-old Leghorns over a 14-day period, 30 birds/group. Normal rations consisted of 16.5 Percent crude Protein and 66 Percent

digestible nutrients

b Excluding zeolite.

c Feed efficiency - weight gain/feed intake (excluding zeolite).

d Cp = clinoptilolite, Mo - mordenite.

Table 5.—Apparent Caloric Efficiency of Zeolite in Chicken Rationsa

d Starter rations (O to 4 weeks) a Adapted from data of Arscott (1975)

e55 ppm Zinc bacitracin b Feed consumed, excluding zeolite

C Feed efficiency value = weight/feed consumed (excluding zeolite) Finisher rations (4 to 9 weeks)

References

As currently defined for the Environmental Protection Agency (EPA) regulations concerning Concentrated
Animal Feeding Operations (CAFO’s), caged layers with wet (wash down) manure handling have
a different classification than caged layers with dry manure handling as shown in Table 1.

Table 1. Comparison of EPA and USDA Definition of Number of Animals in 1,000 Animal Units.

                (from EPA Cost Methodology Report for Swine and Poultry sectors, 2001)

According to EPA, there are an equal number of wet and dry caged layer facilities with > 1,000 Animal Units
in the U.S.  Most of the wash down manure caged layer operations are in areas of the south where freezing
(<28^oF) occurs infrequently.

Assumed Food consumption and Manure Production

Caged layers daily consume 2,000-2,600 lbs of feed per day per 100,000 head and daily produce
2,000-3,400 lbs of fresh manure (moisture @ 70-80%).

Total nitrogen content of fresh manure averages 1.5-2.0 % (@50-70 % moisture), but initial     
ammonium concentrations are only about 0.57-0.77 %; the remainder is organic-bound N.

Therefore 1 million hens will produce 10-17 tons of fresh manure (@ 70-80 % moisture) daily.

Wash down Manure Handling and Properties

Liquid slurry (in ponds or lagoons), after 6-12 months storage typically contains 62 lbs of total N, 42 lbs of
which  is ammonium per 1,000 gallons.  At a value of about $0.35/lb of N, each 1,000 gallons has a nitrogen
nutrient value of  $22. If injected into soil as liquid, it has about 80% N availability to plants the first year.
 

Associated anaerobic lagoon sludge typically contains 26 lbs of total N, and 8 lbs of this is ammonium N per
1,000 gallon.  The value of N in this sludge is about $9 per 1,000 gallons.  If injected as liquid, it has about
60 % plant availability in the first year.
 

Anaerobic lagoon liquid typically contains 179 lbs of total N (154 lbs of this is ammonium) per acre-inch
(of liquid in the lagoon).  When injected in the soil as liquid it has 90 % plant availability.
 

Many operations will be required to have covers on the lagoons to minimize heat and associated loss of
ammonia (gas).
 

Addition of zeolite to the fresh manure in small amounts would provide the best chance for capture of
ammonium because fresh material has the highest ammonium N concentration.  After washing down,
the ammonium concentrations in the liquid is very diluted.

Adding BRZ zeolite to the Feed

Addition of zeolite to the feed @ 1 %  for 1 million birds amounts to 2,000-2,600 lbs/day or 365-475 short
tons/year.
 

The rate of addition of zeolite to the fresh manure is uncertain in the absence of testing different application
rates.  However, if 1 million hens produce 10-17 tons of fresh manure which has 75% moisture, then the total moisture is 7.5-12.75 tons.  The addition of the zeolite to fresh manure will significantly reduce odor and
reduce nitrogen losses to the atmosphere.

SELECTED REFERENCES

Anonymous, Nutrient composition and sampling procedure: p. 1-10.

[http://ces.soil.ncsu.edu/soilscience/publications/soilfacts/AG-439-05/body.htm]
 

Camberato, J., Lippert, B., Chastain, J., Plank, O., 1996, Land application of animal manure: p. 1-12. [http://hubcap.clemson.edu/~blpprt/manure.html]

Congressional Research Service, National Council for  Science and the Environment, 1998,
Animal Waste II: 98-451, P. 1-9. [http://www.cnie.org/nle/ag-48a.html]

Office of Wastewater Management, Environmental Protection Agency, 2000, Guidance manual and sample
NPDES permit for Concentrated Animal Feeding operations: p.1-117.

Office of Water, Environmental Protection Agency, 2001, Cost Methodology Report for Swine and Poultry
Sectors: EPA-821-R-01-018, p. 1-221.

Poultry Waste Management, 1998, Environmental Impacts of Poultry Waste: Poultry Water Quality
Consortium, Chattanooga, Tennessee, p. 1-41.

INTRODUCTION

Proposed Environmental Protection Agency (EPA) regulations concerning Concentrated Animal Feeding Operations (CAFO’s) will force several changes in all large animal/poultry farms in the United States within
the next few years. Several states have already passed statutes concerning regulation of CAFO’s.  The
present abbreviated report was prepared to formulate methodologies or approaches to achieve compliance
with the proposed regulations in the most cost-effective manner without significant interruption of current
operations for caged layers used in egg production.  A major part of the proposal relates to integrated use
of natural clinoptilolite (a mineral of the zeolite group) for improving poultry health, reducing ammonia
emissions from manure, retaining nitrogen in poultry manure, and thereby producing a poultry manure
product that is valuable as fertilizer and soil conditioner.  The CAFO regulations include handling and
treatment of water used in egg-washing.

This proposal will include a section on the properties of the clinoptilolite referred throughout as zeolite. 
A zeolite produced by Bear River Zeolite Company is recommended for uses here because of the high
degree of suitability of this product for agronomic and animal feed uses.  We also provide information
on other commercially available natural zeolites (clinoptilolites) for comparison of chemical and physical
properties.

SYNTHESIS AND OBJECTIVES FOR CAGED LAYER HEALTH, PRODUCTIVITY, AND  REGULATORY COMPLIANCE WITH REGARD TO MANURE GENERATION, HANDLING,

AND NUTRIENT USE IN AGRONOMIC APPLICATIONS

OBJECTIVES, APPLICATIONS, AND LOGIC

Improving caged layer health and productivity by addition of small amounts of zeolite to the feed for
zeolite adsorption of ammonium nitrogen in the alimentary tract and also to enhance feces solidification
due to liquid contained in zeolite pore space.   In addition, clinoptilolite is a chemisorbent which has the
ability to tightly bind and immobilize aflatoxins and thus reduce their bioavailability.

Reduce ammonia gas (NH₃) generation in caged layer residence and manure storage facility by capturing ammonium (NH₄) by ion exchange into zeolite.  This is accomplished by adding a small amount
(e.g. 1 wt. %) of zeolite to the layer feed, and adding a small amount (to be determined) of zeolite to fresh
manure.  Capture of ammonium by zeolite addition to feed occurs in the gut and some ammonium present
in the feces is exchanged into zeolite added to the fresh fecal material.  The exchange of ammonium into
the zeolite protects it from nitrogen (N) loss by alteration to ammonia gas or other gaseous nitrogen forms.
 

Reduction of ammonia generation from fecal material will reduce noxious odors and thereby minimize
attention of flies and reduce atmospheric generation of  particulate matter (PM₁₀)10-micron-sized
particulate nitrogen-bearing salts that interfere with respiration of  humans, poultry, and animals. 
Ammonia emissions from litter have been found to be a source of ammonia pollution in acid rain in Europe.
 

Isolate and age manure in anaerobic conditions using silo bag containers to enhance heat generation in
order to destroy potentially toxic pathogens, minimize N loss to atmosphere, eliminate rainfall transport
of nutrients and pollutants to the watershed, and remove odor exposure to the local environment.  This
isolation might be used to precede composting, either on-site or off-site, depending upon whether or
not it is desirable to emit strong odors on-site.
 

If composting is desired, aerobic (oxygen-using) conditions are necessary to support and enhance
microbial activity; this requires blowers or fans, or turning the compost with a front-end loader or a
commercially available compost turner.  Temperatures in the compost must be maintained at levels
above approximately 130^oF (but lower than 150-160^oF) in order to kill any pathogens.  This composting
will expose the manure to the atmosphere and allow odors and ammonia gas to be emitted locally.
 

Ion exchange of ammonium from the fecal material displaces potassium and calcium from the zeolite and
these plant-essential elements will be available as nutrients in the manure.
 

Introduction of zeolite-plus-manure to the soil will have the beneficial effects of enhancing water retention, increasing ion-exchange capacity of the soil, providing a medium for future capture of ammonium nitrogen,
and increasing aeration properties of the soil due to the high internal surface area of the zeolite.
 

Egg-washing water can be recycled after filtration in a zeolite bed to remove suspended solids and to trap
bacteria (e.g. ecoli, etc.) in the zeolite pores.
 

Phytase added to the food would improve phosphorous utilization, and thereby minimize phosphorous
pollution in the fertilizer application.

TYPICAL CAGED LAYER FOOD CONSUMPTION AND MANURE PRODUCTION

Caged layers daily consume 2,000-2,600 pounds of food per day per 100,000 head and daily produce
2,000-3,400 pounds of fresh manure (moisture @ 70-80 %).
 

Total nitrogen content of fresh manure is 1.5-2.0 % (moisture @ 50-70 %), but ammonium concentrations
are only about 0.57-0.77 %.  [The remainder of nitrogen is in organic nitrogen compounds where nitrogen in unavailable for plant nutrition until the nitrogen is converted to either ammonia, ammonium, nitrate, or nitrite.]
 

Therefore 3.5 million hens will produce 35-59.5 tons of fresh manure (moisture@ 70-80 %) daily.

RATIONALE FOR USING CLINOPTILOLITE ZEOLITE FOR CAGED LAYER APPLICATIONS RELATED
TO ENVIRONMENTAL REGULATIONS, POULTRY HEALTH, AND AGRONOMIC APPLICATIONS OF
MANURE FOR FERTILIZER AND SOIL AMENDMENT

For agricultural/agronomic end-use as fertilizer and/or soil conditioner, after use as feed additive for
poultry/animals and addition to raw manure to retain ammonium, the zeolite must have the certain
chemical and physical properties.  Some of the chemical and physical properties of commercially
available clinoptilolite zeolite in the western United States are listed in Table 1.  This list may not include
all of the commercially available clinoptilolites in the western U.S. but it does include major producers and
those available listings on the Internet.

The Bear River Zeolite (BRZ) has several properties that make it most suitable for both feed additive and fertilizer/soil amendment use as follows:

1.      The BRZ zeolite has at least 25% more ammonium exchange capacity than any other clinoptilolite
         (using AN20 agriculture solutions) that is commercially produced in the United States.

2.      Pore space measured quantitatively, is about 25 m²/gram for BRZ, as compared with the zeolite
         produced by St. Cloud Mining which has about 14 m²/gram (Table 1).  Although the zeolite produced
         by Zeotech, Inc. has a very much higher surface area (Table 1), the surface area is due to the large
         surface area of the “clay” or “mica” in that product; it is not due to internal surface area.  Pore space
         is the non-chemical void space which allows for aeration and water occupancy in this void space or
         porosity/permeability to fluids and gases.

3.      The Zeotech, Inc. product contains an X-ray diffraction detectable amount of calcite which if used
         in the agricultural application of manure fertilizer will promote conversion of ammonium to
         ammonia gas due to elevation of manure solution pH above about 6.0-7.5.

4.      Although salinity and sodicity (Na) have not been emphasized by marketers of clinoptilolite in
         agricultural/agronomic/horticulture applications, this aspect is very important to field applications
         because of the toxicity of both salinity and sodicity to plants. If manure amended by clinoptilolite
         zeolite has significant amounts of sodium added to the fertilizer product due to exchange of
         ammonium that displaces sodium in the clinoptilolite, the plants may be adversely affected by
         excess sodium that is toxic to plants and inhibits germination.

Clinoptilolite-rich rocks with more than about 1 weight percent sodium (Na) may have adverse affects on
plant growth if the Na is ion-exchangeable.

Table 1. Composition of some North American clinoptilolites for commercial sale by producers or marketers.
n.r. = not reported, The EcoSand, Zeo,Inc. product is from the St. Cloud Mining property.

NUTRIENT VALUE OF MANURE FOR FERTILIZER

For caged layers the average concentrations of  N, P₂O₅, and K₂O in fresh manure @ 60% moisture are:

N   = 1.8 %

P₂O₅ = 2.0

K₂O = 1.0

At 50 % loss of N prior to field application and values per pound @ N = $0.35, P₂O₅ = $0.23,
and K₂O = $0.15, the value of the poultry manure contribution nutrients @ 30% moisture after dry
stacking is:

N =   $ 12.60

P₂O₅  = 18.40

K₂O  =   6.00

Total =$37.00 per ton + 25%

            This value of the plant nutrients does not include the value of the  K in the clinoptilolite.

SELECTED REFERENCES

         Anonymous, Poultry manure management and utilization problems and opportunities:
Ohio state university Extension Bulletin 804, p.1-5.
[http://www.ag.ohio-state.edu/~ohioline/b804/804_7.html]

Anonymous, 1996, Land application of animal manure: [http://hubcap.clemson.edu/~blpprt/manure.html]

Allen, E.R., and Ming, D.W., 1995, Recent progress in the use of natural zeolites in agronomy and
horticulture, in Ming, D.W., and Mumpton, F.A., eds. Natural Zeolites ’93:
Occurrence, Properties, Use, June 20-28, 1993, Boise, Idaho, International
Committee on Natural Zeolites, Brockport, new Your, p. 477-490.

Allen, E.R., Hossner, L.R., Ming, D.W., and Henninger, D.L., 1996, Release rates of phosphorous,
ammonium, and potassium in clinoptilolite-phosphate rock systems:
Soil Science Society of America Journal, v. 60, no. 5, p. 1467-1472.

Amon, M., Dobeic, M., Sneath, R.W., Phillips, V.R.,Misselbrook, T.H., and Pain, B.F., 1997,
A farm-scale study on the use of clinoptilolite zeolite and De-Odorase for
reducing odor and ammonia emissions from broiler houses:
Bioresource Technology, v. 61, no. 3, p. 229-237.

Cerjan-Stefanovia, S., and Curkovic, L., 1997, Selectivity of natural zeolites for tosic ions, in Kirov,
G., Filizova, L., and Petrov, Ol,m eds. Natural Zeolites—’95:
Proceedings of the Sofia Zeolite Meeting ’95: Bulgaria,
Pensoft Publishers, p. 121-126.

Cintoli, R., Di Sabatino, B., Galeotti, L., and Bruno, G., 1995,  Ammonium uptake by zeolite  and
treatment in USAB reactor of piggery wastewater:
Water Science and Technology, v. 32, no. 12,
(Waste Management Problems in Agro-Industries 1995) p. 73-81.

Dakovic, A., Tomasevic-Canovic, M., Dondur, V., Radosevic, P., and Dumic, M., 1998, The kinetics
of aflatoxin B₁ adsorption on Ca-clinoptilolite, in Ribnikar, S., ed. 4^th
International conference on the Fundamental and Applied Aspects of Physical
Chemistry: Belgrade, Yugoslovia, Society of Physical Chemists of Serbia, p. 198-200.

Desborough, G.A., and Crock, J.G., 1996, Nitrogen-loading capacities of some clinoptilolite-rich
rocks: U.S. Geololgical Survey Open-File Report 96-661, p. 1-17.

Desborough, G.A., 1996, Clinoptilolite-rich rocks in agricultural use for soil amendment and potential
nitrogen-pollution mitigation: U.S. Geological Survey Open-File Report 96-065.

Desborough, G.A., 1996, Some chemical and physical properties of clinoptilolite-rich rocks:
U.S.  Geological Survey Open-File Report 96-265, p. 1-7.

Dwyer, M.R., Kubena, L.F., Harvey, R.B., Mayura, K., Sarr, A.B., Buckley, S., Bailey, R.H., and
Phillips, T.D., 1997, Effects of inorganic adsorbents andcyclopiazonic
acid in broiler chickens: Poultry Science, v. 76, p. 1141-1149.

Gilbert, J.S., O’Meara, P.M., Crock, J.G., Wildeman, T.R., and Desborough, G.A., 1999,
Adsorption capabilities of selected clinoptilolite-rich rocks as it relates to mine
drainage remediation: U.S. Geological Survey Open-File Report 99-17, p. 1-50.

Hervey, R.B., Kubena, L.F., Ellissalde, M.H., and Phillips, T.D., 1993, Effacy of zeoitic ore compounds
on the toxicity of aflatoxin to growing broiler chickens:
Avian Diseases, v. 37, p. 67-73.

Huang, Z.T., and Petrovic, A.M., 1994, Clinoptilolite zeolite influence on nitrate leaching and
nitrogen use efficiency in simulated sand based golf greens:
Journal of Environmental Quality v. 23, no. 6, p. 1190-1194.

Lon-Wo, E., Zaldivar, V., and Margolles, E., 1993, Effect of natural zeolites on poultry feeding with
different nutritional levels of high mycotoxin contamination:
Cuban journal of Agricultural Science, v. 27, no. 2, p. 199-204.

Mahimairaja, S., Bolan, N.S., hedley, m.J., and Macgregor, A.N., 1994, Losses and transformation of
nitrogen during composting of poultry manure with different amendments:
An incubation experiment: Bioresource Technology, v. 47, no. 3, p. 265-273.

Mitchell, C.C., and Donald, J.O., 1995, The value and use of poultry manure as fertilizer:
Alabama Cooperative Extension System,
Circular ANR-244, p. 1-6. [http://hubcap.clemson.edu/~blpprt/Aub+244.html]

Nguyer, M.L., and Tanner, C.C., 1998, Ammonium removal from wastewaters using natural
New Zealand zeolites:
New Zealand Journal of Agricultural Research, v. 41, p. 427-446.

Pond, W.G., 1995, Zeolites in animal nutrition and health: A review, in Ming, D.W., and
Mumpron, F.A., eds., Natural Zeolites ’93: Occurrence, Properties, Use,
June 20-28, 1993, Boise, Idaho, International Committee on Natural Zeolites,
Brockport, New York p. 449-457.

Preston, K.T., and Alleman, J.E., Co-immobilization of nitrifying bacteria and clinoptilolite for enhanced
control of nitrification:
Proceedings of the 48^th Industrial Waste Conference, p. 407-412.

Ramos, A.J., and Hernandez, E., 1997, Prevention of aflatoxicosis in farm animals by means of hydrated
sodium calcium aluminosilicate addition to feedstuffs:
A review: Animal Feed Science and Technology, v. 65, p. 197-206.

Saad, N., Aflatoxins: Occurrence and Health Risks, 10 p. [http://www.ansci.cornell.edu/plants/toxicagents/aflatoxin/aflatoxin.html]

Tomasevia-Canovic, M., Dumic, M., Vukicevic, O., Masic, Z., Zurovac-Kuzman, O., and
Dakovic, A., 1997, Adsorption of mycotoxins on modified clinoptilolite,
in Kirov, G., Filizova, :l., and Petrov, O., eds., Natural Zeolites—
’95: Proceedings of the Sofia Zeolite Meeting ’95:
Sofia, Bulgaria, Pensoft Publishers, p. 127-132.