entac emulsions: information brief for the environmental … · 2018-06-12 · entac emulsions:...

ENTAC EMULSIONS:

INFORMATION BRIEF FOR THE ENVIRONMENTAL CHOICE™ PROGRAM

Report Prepared By: Stantec Consulting Ltd. 160 – 7070 Mississauga Road Mississauga, Ontario L5N 7G2 Report Prepared For: Entac Emulsions 821 Woodward Avenue P.O. Box 936, Station Lcd-1 Hamilton, Ontario L8L 7W9 Ref. 1609 23019 March 2005

ENTAC EMULSIONS: INFORMATION BRIEF FOR THE ENVIRONMENTAL CHOICE™ PROGRAM

Ref. 1609 23019 March 2005 ii

Table of Contents

Page

1.0 INTRODUCTION – WHAT IS ENTAC/HOW DOES ENTAC WORK? 1

1.1 What is Entac? 1

1.2 How Does Entac Work? 1

1.3 How is Entac Different From Other Dust Suppressants? 2

2.0 ENTAC’S DEALINGS WITH THE ONTARIO MINISTRY

OF ENVIRONMENT 5

3.0 ENTAC LEADERSHIP IN THE DUST SUPPRESSANT MARKET 7

3.1 Environmental Stewardship and Ecological Testing 7

3.2 Comparison to Other Products and Efficacy of Entac 8

4.0 BIOCHEMICAL OXYGEN DEMAND (BOD) AND BIODEGRADABILITY 10

4.1 BOD 10

4.1.1 Results 11

4.1.1.1 Product Only 11

4.1.1.2 Gravel Coated with Cured Product 12

4.2 Biodegradability 14

4.3 Conclusions Regarding BOD 14

5.0 ENDOCRINE DISRUPTING SUBSTANCES (EDSs) 16

6.0 SUMMARY 18

7.0 REFERENCES 19


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1.0 INTRODUCTION: WHAT IS ENTAC/HOW DOES ENTAC WORK?

1.1 What is Entac?

Entac is an emulsion – that is, it is a stable mixture of immiscible liquids held in

suspension by small amounts of finely divided Tall Oil Pitch (TOP) particles and

emulsifiers. Tall Oil Pitch is a natural product obtained from the pulping process of

pinewood. The name “tall oil” is derived from the Swedish word “Talloja”, which

means, “pine oil”. Pine oil is a mixture of resins and fatty acids that occur naturally in

pine trees.

Once the pulping process is complete, the remaining alkaline solution is acidified to

produce sodium salts, or saps, of the various tree-based acids. These “soaps” are

separated and treated to produce tall oil.

As part of Entac’s operations, the tall oil pitch is mixed with water and other materials

in a proprietary process, with the end product being Entac. The key to producing

Entac is regulating the physical and chemical characteristics of the product by

precisely controlling the optimum grain size and relative proportions of the product

ingredients. The performance of the emulsion depends on obtaining a balance

between electronegativity and electropositivity of the emulsifiers, and on precise

control of the size of the pitch particles. Once this is obtained, the emulsion is

chemically and physically stable, and the pitch particles will remain evenly dispersed

in the emulsion, which allows the material to be stored, transported, pumped and

applied at ambient temperatures. It also allows Entac to produce a chemically and

physically consistent product for each application.

1.2 How Does Entac Work?

There are several steps, including product preparation, particle coating and product

setting. Product preparation is discussed above (1.1). Entac products work by

coating all the particles in a roadbed surface, from the finest dust particle to coarse

sands to pebbles and stones. Complete coating is essential to providing structural

integrity to the seal on the roadbed, because if all particles are not coated, they will

be free to move with road use and weaken the bonded material.

The next step is the “setting” or curing of the product. When the product sets, it

hardens and binds the particles together. The depth to which particles are coated

and cured can be adjusted by varying the rate of dilution of the product. The mixture

sets rapidly and provides a waterproof, insoluble, non-leaching, non-corrosive, non-

toxic and non-slippery seal that has structural integrity to whatever depth is desired.


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1.3 How is Entac Different From Other Dust Suppressants?

The main difference is that Entac is composed of natural ingredients, and it will not

contribute undesirable metals, organic chemicals, or other compounds to the

environment. It will biodegrade over time, and this ultimately produces some

naturally occurring breakdown products which behave no differently in the

environment than other plant or tree products, such as leaves, pine needles and

wood fibre.

Other dust suppressants are composed of oils, or sugar or lignin-based materials, or

other raw materials such as calcium chloride or magnesium chloride. A few are

based on acrylic polymers or latex formulations. All of them, including Entac,

eventually break down to produce oxygen-consuming organic compounds (with the

exception of calcium chloride and magnesium chloride based dust suppressors).

There are two fundamental characteristics (besides marketplace aspects like cost,

level of effort to apply, and so on) to consider in comparing the different types of dust

suppressants: how well the product performs as a dust suppressant, and the degree

to which the product affects the environment. Based on these characteristics, it is

possible to distinguish between the various classes of dust suppressants. Fairly

straightforward differences emerge if one groups the various dust suppressants into

two very broad groups: Group One consists of the older, traditional products like

water, waste oil, calcium/magnesium chloride, or Dombind-like materials, and the

generally newer products (Group Two) such as the lignosulfonates, acrylic polymers,

latex-based, and tall oil emulsion based products. The main differences are as

follows:

Group One

Waste oils are somewhat effective, but contribute numerous undesirable

materials to the environment. These include wear metals (some of which may be

toxic), a high biochemical oxygen demand (BOD), and numerous petroleum

hydrocarbons that can be toxic to aquatic organisms once the oil is washed into

watercourses.

Water is effective for a short time as a dust control agent, but as traffic runs over

the surface, the presence of water actually makes the subsequent dust problem

worse. This is due to the fact that water doesn’t provide structural integrity to the

particles on the road surface, but does provide a degree of lubrication such that

particles grind against one another and become less coarse, and fine particles

become even finer. Once the water evaporates, there is a greater likelihood of

finer dust becoming wind-borne. Also, water only remains effective as long as the

surface remains wet, so water can be considered a transient, non-effective and

environmentally harmful dust suppressant.


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Calcium/magnesium chloride, when applied at high enough rates, can form a

crust on the topsoil surface. Both calcium chloride and magnesium chloride are

deliquescent and can draw water vapour from the air, which forms a crusty layer.

However, both chemicals are also soluble in water, which means that the crust

only lasts until rain, heavy dew, or snow/ice melt water dissolves out the chloride.

The subsequent step is that the dissolved chloride will eventually be washed into

the nearest downgradient waterbody, resulting in further increases in the chloride

content of surface and groundwater. If the calcium/magnesium chloride remains

undissolved, traffic abrasion will grind the salts to very fine dust, which eventually

becomes airborne and will then eventually fall out or be rained out into the

environment.

Waste cardboard-based material (such as Dombind) has been banned for use

in Ontario due to the presence of unacceptable levels of dioxins, furans and

phenols in the product. While the ban is a good thing from an environmental

perspective, there has been a tendency on the part of some members of the

public to believe that all products derived from any part of the paper industry must

also contain dioxins, furans and phenols. This is simply not the case and can be

demonstrated by testing.

The remaining products constitute a second group.

Group Two

Lignosulfonates are not particularly effective, mainly because they are water-

soluble. These materials also come from the pulping process, which produces

two general families of products – sugars and gums. Lignosulfonates are from

the sugar group and are water-soluble, while tall oil pitch (Entac) is from the gum

group and is insoluble. Because of their solubility, lignosulfonate products are

leached out of the road substrate and have a relatively short life span. They are

also less stable during rain or freeze-thaw events, and are thus not as effective.

Acrylic polymers are also used as dust suppressants. These products work by

forming a skin on the road surface. The product has little penetration into the

aggregate/sand of the roadbed and road surface, but the ”skin” offers a degree of

dust control. Because it doesn’t “wet” the road material, it doesn’t bind it or add

much structural integrity, so traffic wear quickly results in areas with little intact

“skin”. Rain can quickly cause channeling, which can result in pot-holes and

other road defects.

Acrylates and some of the breakdown products are not benign in the

environment. Some generation of BOD will occur with acrylates.

Latex-based suppressants are water soluble, but after application they “set” -

much like latex paint on a wall. The object is to basically fix or stick the dust to

the road, which works well until rain, dew, or other moisture penetrates the latex.


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These products are not waterproof, and because they add a layer on top of the

road, they do not provide additional structural integrity, and with traffic wear and

water penetration, channelization occurs and the surface becomes ineffective.

Generation of BOD in watercourses will occur with this product.

Tall oil emulsions provide good penetration into the road surface, and the

material quickly “sets” which provides additional structural integrity. Most tall oil

based products are prepared with rudimentary control over the electrokinetic

properties of the emulsion and the size of the tall oil pitch particles, and this

results in significant performance differences between such products. The key to

obtaining a long-lasting water resistant coat to specified depth in a roadway is to

have emulsion particles small enough to bind to the smallest road surface

particles. Most tall oil products provide a good topcoat, but unless they have

been precisely milled, the particles will not completely bind all road aggregate

particles, which means that the aggregate won’t be completely locked together.

When this happens, road wear will result in areas where the aggregate comes

apart, causing pot-holes and other road problems.

Entac’s direct competitors – those based on tall oil emulsions – have not

developed the ability to properly mill the tall oil pitch to the necessary

specifications, and they do not have access to Entac’s proprietary process. For

these reasons, the competing products are not as effective and they lack

consistency – in other words, each batch can be quite different in its chemical and

physical characteristics.

Entac is tall oil based, and it is prepared under rigorous, precise milling, mixing

and electrokinetic conditions. The emulsion particles are the finest diameter

known in such products, which helps with penetration, particle coating, and

coverage to specified depth. This results in an insoluble, strong surface coating

and stabilization of roadway aggregates, which results in water resistance

throughout the treated depth. The application lasts longer and remains effective

over its lifetime.

Environmental concerns are limited to the inevitable production of oxygen-

consuming organics, which is a common concern for all dust suppressants except

water and calcium/magnesium chloride, each of which have other serious

environmental disbenefits. Because Entac is very effective, relatively small

quantities are required on an area/time basis, which means that relatively less

BOD is associated with its use. The BOD issue is further commented upon in

Section 4.0 of this report.


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2.0 ENTAC’S DEALINGS WITH THE ONTARIO MINISTRY OF ENVIRONMENT

The original Entac company (“Entac”) underwent ownership changes during 2002 –

2003. Prior to this, the dust suppressant named “Enviroseal” had undergone

extensive testing in private laboratories (MDS Environmental), and based on the

results had been provided MOE agreement in 1996. The ownership changes in 2002

– 2003 resulted in the company splitting into two parts. Both parts continued to

manufacture a dust suppressant product based on tall oil emulsions. Entac Inc.

manufactures “Entac” product, while Enviroseal manufactures a product through a

process unknown to us under the name “Enviroseal”.

As a result of this split, the MOE had a concern that the Entac product might not be

the same material as the one MOE had previously listed. This concern was

unfounded, as the Entac product is made from exactly the same base material as the

previously listed “Enviroseal”, with the most substantive change being process

alterations which allowed for a finer emulsion, better control over the emulsion mixing

process and subsequent improved product performance with vastly improved

consistency in the makeup, characteristics, and efficacy of the product.

A copy of MOE’s letter of July 3, 2003 to Entac Inc. is enclosed. As can be seen,

MOE requested complete re-testing of the product, which Entac immediately

responded to with additional testing.

Entac senior staff met with MOE to establish their requirements, if any, beyond those

stated in the attached letter of July 3, 2003, and were instructed to perform “total”

metal and organic chemical testing on the product and the results would be

compared against the Table A soil criteria from MOE’s publication “Guideline for Use

at Contaminated Sites in Ontario”, Revised 1997. These soil quality criteria were

developed by the Ministry “to provide protection against the potential for adverse

effects to human health, ecological health and the natural environment” (p. ii). In

addition, Entac was asked to perform ecotoxicological testing on the product.

The soil criteria were established based on human health and ecological health

factors for various soil uses. If a soil is found to have levels of these parameters

below the criteria, no environmental adverse effects will exist. As the MOE document

states: “A site will have no environmental adverse effect when the generic criteria

levels in Tables A to D or levels developed as part of a full site specific risk

assessment (SSRA) clean up have been met. Physical hazards such as the potential

for explosion may also have to be considered. There may be circumstances where

concentration limits at a site may exceed the guideline values and still not create an

“adverse effect”; this can only be determined on a case-by-case basis.”

Tables A to D provide criteria for more than 110 environmentally-significant

parameters, including metals, organic compounds, chlorinated organics, PAHs,


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PCBs, dioxins and furans, and inorganic anions. Table A criteria (Surface soil criteria

for agricultural, residential/parkland, industrial/commercial land use) are the most

stringent of MOE’s generic soil criteria.

The Entac product results (attached) show that there were no exceedances for any

parameter in Table A. In fact, most parameters were not detected, despite the fact

that the testing was performed using the most sensitive analytical equipment and

protocols commercially available. The ecotoxicity testing showed no toxic effects

whatsoever for Rainbow trout and for Daphnia magna. No trout or daphnia died, and

no effect of any kind was observed during the testing.

A copy of Entac’s consultants letter to MOE, which accompanied the results, and a

full copy of the results of the testing are attached.

To summarize, Entac has been extensively tested for the full range of chemicals on

the U.S. EPA and MOE priority environmental chemical lists including metals,

inorganic chemicals, organic chemicals including volatile organic compounds, semi-

volatiles, extractables such as PAHs, PCBs, phenols and phenolic compounds,

dioxins and furans. It has also been tested by Open Scan Gas Chromatography/

Mass Spectrometry, to determine whether it contains any compounds not detected

using the U.S. EPA and MOE priority environmental chemical lists. For most of these

chemicals, none were even detected. Where detections occurred, as was the case

for some naturally occurring metals and organic compounds, the levels were

consistently below any applicable federal or provincial criteria.

The Entac product has also undergone ecotoxicity testing, and it has been shown to

fall in the category of materials with no measurable toxic effects on the two mandated

species, Rainbow trout and Daphnia magna.

To date Entac has not had a response from MOE. It is my view that Entac has met

all of their requirements, and that the product “will have no environmental adverse

effect”.


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3.0 ENTAC LEADERSHIP IN THE DUST SUPPRESSANT MARKET

There are several aspects to consider in terms of leadership, including:

Environmental stewardship,

Efficacy of the product,

Ongoing intensive and extensive testing for possible environmental

effects, and

Comparison to other products used for dust suppression.

Entac has a strong environmental ethic that is part of the reason they’re in the

business, and while they can demonstrate that their product is more effective than

those of their competitors for any given application, it is difficult for them or for a

consultant to perform “head-to-head” comparison of their product’s environmental

testing results to those of their competitors, because neither Entac nor I have access

to their test data. However, I am aware of some of the environmental problems that

have arisen for some competitors, and will use some of this information for

comparative purposes.

3.1 Environmental Stewardship and Ecological Testing

The concept behind the current product was to improve upon the original product

from both an environmental perspective and a performance perspective. The original

Entac product was and continues to be manufactured from a natural material derived

from the pine tree. The basic starting material is tall oil pitch, which is a mix of rosin

and fatty acids obtained from the digestion (pulping) of pine wood (the word “tall” in

tall oil is Swedish for “pine”).

This starting material is environmentally benign and ongoing testing has repeatedly

shown that it passes all of the chemical and ecotoxicological testing requirements

that have been required. The process by which it is made is also a good example of

biochemical recycling, as it uses a by-product of the wood pulping process used to

manufacture paper, and turns it into an environmentally helpful material.

Details on product constituents and the manufacturing process are provided in

Section 1.0 “Introduction”.

The use of the material is intrinsically helpful for the environment, as it prevents dust,

debris, and other particulate matter from becoming airborne and increasing the load

of particulates in the atmosphere. This also minimizes the potential load of soluble

and insoluble particulates due to fall-out from atmospheric sources, as well as the


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amount of material washed out of the atmosphere by precipitation (rain, snow, and

other hydrometeorites).

A secondary but major environmental benefit is the reduction in dustfall and rainfall

related matter that accumulates on the ground, on roof-tops, pavement and other

surfaces, which is ultimately washed into creeks, rivers and lakes by stormwater

runoff.

These are very significant environmental benefits, and they arise from the application

of a product that has no measured environmental disbenefits.

There are alternative approaches to dust suppression. The traditional ones, based

on materials like waste oils, lignosulfonates and byproducts of hardwood pulping and

cardboard recycling such as “Dombind”, were not as effective at achieving dust

control as Entac, but more importantly, testing of such products shows they contain

various chemical of environmental concerns.

As shown in Section 2.0, extensive testing of the Entac product showed that it

contains some naturally occurring metals and organic compounds, at levels well

below any applicable federal or provincial criteria, and ecotoxicity testing of the

product showed no measurable toxic effects on aquatic organisms.

3.2 Comparison to Other Products and Efficacy of Entac

Road Shoulders (granular stabilization): Asphalt-based emulsions are currently

being used to seal road shoulders. These products are reported to contain up to

40% organic chemical solvents and have a negative impact on the environment in

terms of both air quality and water quality. Asphalt emulsions form a surface seal

and do not provide structural integrity to the shoulder structure. The Entac product

not only produces the required waterproof seal but also locks the aggregate together,

which provides structural integrity and forms a hard wear resistant shoulder.

Roads (dust control): As previously mentioned in this report, products presently

used include oils, calcium/magnesium chlorides, lignosulfonates, polymers and

water. The performance of these various products is generally limited to a short term

solution, and most of these products generate environmental hazards. The emulsion

products provide better performance and, in the case of the Entac product, no known

environmental problems. Entac’s emulsion product is superior to other emulsion

products because it is the result of an engineered application program that ensures

performance of the final road structure. For example, a competing tall oil pitch

emulsion produced in the USA requires twenty seven gallons of their emulsion

product per ton of aggregate used, while Entac emulsion is added at twelve gallons

per ton and produces the same as or better binding performance. The enhanced

performance of the Entac product is attributed to superior chemical and physical

properties and engineered application procedures that ensure complete particle

coating as well as maximum densification of the aggregate blend.


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Stockpile Sealing: There are several technologies used to seal stockpiled materials

such as tarps, calcium and magnesium chlorides, plastic sheeting, latex polymers,

and petroleum based oil products. Each of these technologies generate

environmental issues either due to limited performance, leaching of undesirable

chemicals into surface water and groundwater, waste disposal issues for products

such as plastics after use or to replace failed sections of the seal membrane. Entac

is used by industry to seal a variety of stockpiled products such as sand/salt,

minerals, PRB coal, coke, arsenic contaminated waste, steel industry revert

materials, silica sands, casting sands and soils. The seal produced is water

resistant, non-leaching and can be designed to last for months or years depending on

the customer’s requirements. The Entac product has been endorsed as best practice

by the PRB coal users association for the sealing of coal at fossil fuel power utilities.

It should be noted that some emulsion products have been cited in stockpile sealing

failures. Over the last year there have been several stockpile sealing failures related

to sand/salt piles sealed by competing emulsion products. These failures were the

result of poor emulsion characteristics and improper application procedures. The

seals failed within twenty-four hours of application and subsequent attempts to

correct the problems also failed. The difference between Entac’s products and those

of competing emulsion-based products is that Entac had developed the ability to

manufacture emulsions that completely coat each particle in the material that is to be

sealed, and the physical and chemical characteristics of the emulsion can be

adjusted to match the specific requirements of each application. This engineered

application program, along with complete control of the chemical and physical

characteristics of the emulsion is what differentiates Entac from its competitors.

Mining Industry: Entac products are widely used for a variety of mining applications

such as heavy haul road stabilization, mine tailings dust control, stockpile sealing,

erosion control, dam/dike/berm stabilization and underground road construction. The

Entac products have been recommended by some of the leading mining companies

as best practice for the aforementioned applications. The competitive products in the

mining industry are water, tarps, building structures, oils, calcium/magnesium

chlorides and polymers, each of which have limited performance characteristics

and/or adverse environmental impacts.


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4.0 BIOCHEMICAL OXYGEN DEMAND (BOD) AND BIODEGRADABILITY

4.1 BOD

BOD testing provides an estimate of the easily biodegradable organics in a sample.

The BOD test does this by determining the amount of oxygen consumed by bacteria

as they decompose the material. In effect, organic matter in the material becomes

food for the microorganisms, and they consume oxygen as they break down the

organic matter in the sample. The greater amount of oxygen consumed after the

test commenced, the higher the organic content of the test material and the higher

the BOD. Typically the test is carried out over five days, with the dissolved oxygen

(DO) in the sample measured at the beginning and at the end of the test. The

difference in DO is the BOD.

BOD is often used to assess and control high organic strength discharges into

waterways, because the amount of oxygen consumed as the waste decomposes can

overcome the receiving water’s ability to maintain adequate oxygen levels for aquatic

life.

Entac product is comprised of water plus naturally occurring organic constituents, so

by its nature it is biodegradable. However, the product is formulated as a material

that will be effective as a dust suppressant under the rigorous environmental

conditions found in Canada and the United States, so it is designed to not biodegrade

quickly. The amount of oxygen demanding material released is spread out over a

long time period – one to two years in most cases. This feature was designed into

Entac products and was corroborated by biodegradability testing, as discussed in the

following section (4.2)

If one performed a BOD test on the raw product, it should be significantly higher than

the BOD of the applied product. That’s due to the fact that the product sets in/on the

road material immediately after application. The setting of the material accounts for

its relatively long lifespan as a dust suppressant. This also means that unlike most of

Entac’s competitors, it doesn’t need to be re-applied as quickly, which lessens its

burden on the environment relative to competing products.

Entac had its product tested for BOD and for chemical oxygen demand (COD). COD

provides a measure of the total amount of oxygen that can be consumed as the

material is oxidized by powerful chemical oxidants (potassium dichromate in boiling

sulphuric acid).

If the same sample is tested for BOD and COD, the COD should always be

somewhat higher than the BOD.


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Two Entac samples were submitted for analysis:

a sample of the product (7% solids tall oil pitch); and

gravel that had been coated with the product and allowed to cure and seal

(individual pellets of gravel with Entac coating, cured).

The product sample was analyzed directly by taking an aliquot, adding water and

determining the dissolved oxygen before and after five days of incubation (5-day

BOD test).

The cured product on gravel was tested according to a MOE/Toronto Regional

Conservation Authority protocol (MTRCA, March 14, 1989 Revision) which involves a

24 distilled water leach using a 20 to 1 volume to mass ratio of distilled water and

cured product/gravel. After 24 hours of tumbling the mix, an aliquot is removed for 5-

day BOD testing as above.

4.1.1 Results

Sample BOD (mg/L) COD (mg/L)

Product only 24,250 151,800

Gravel coated with cured product 16.4 33

The following discusses these results.

4.1.1.1 Product Only

The COD was four to five times higher than the BOD for the product itself. This

indicates that the product has a relatively small proportion (about 1/4 to 1/5 of the

total) of organic matter that is biodegraded after five days exposure, under optimum

conditions for bacteria to grow and consume the product. It should be noted that the

BOD of the product, which was 24,250 mg/L, is not an indication that the product will

cause elevated BOD in the environment. This is a BOD value obtained on straight

product, and is much higher than the BOD that would be generated under actual

application conditions for the following reasons:

straight product is never applied to road or other surfaces. The product is

diluted by four- to ten-fold depending on the nature of the application; and

the product is cured after application. As can be seen in the BOD data for

the cured product, the BOD levels are much lower – by a factor of more

than 2,000.


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4.1.1.2 Gravel Coated with Cured Product

The sampled was prepared by tumbling a mass of gravel pellets coated with the

cured product for 24 hours in distilled water. The BOD in the sample was 16.4 mg/L,

almost exactly one-half of the COD result of 33 mg/L. If one assumes that the

oxidation of the organic compounds in the Entac product is 95-100% of the

theoretical value (Standard Methods for the Examination of Water and Wastewater,

1998, 20th Edition) then it can be concluded that about ½ of the organic matter was in

a form that was biodegradable within five days, and the remainder was ultimately

oxidizable by dichromate.

However, it is once again important to keep in mind that the treatment given the

sample – tumbling for 24 hours in distilled water – is a much more aggressive

treatment than the cured emulsion receives after an actual real-world application:

the aggregate remains as a structurally intact surface, not as individual

loose pieces of gravel;

the intimate and continuous 24-hour tumbling results in particle collisions,

abrasion, friction and other physical wear that doesn’t occur in practice;

and

distilled water is generally more aggressive with respect to organic

compound dissolution than is natural rain or melt water.

In addition, the BOD value is obtained under ideal conditions; while microorganisms

in the natural environment will break down some organic material as the cured

emulsion ages, they will not function at their ideal metabolistic temperature, or in an

incubated mixture of nutrients, and they will be subject to a host of natural predators

and inhibitors in nature.

Comparison of Entac BOD and COD to Literature Values for Stormwater and

Roads

It is unlikely that the BOD generated by the use of Entac would come close to the

BOD that is present on roadways due to their normal use. Papers dealing with BOD

in stormwater were reviewed by Makepeace (1995). He reviewed 140 articles

containing water quality analysis of stormwater, and he found the following

information:

overall BOD range in published stormwater results 1 to 7,700 mg/L

mean (average) BOD in stormwater literature 7 to 31 mg/L

overall COD range 7 to 2,200 mg/L

mean COD range 7 to 224 mg/L


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Comparing the average of the means yields 19 mg/L for BOD and 115 mg/L COD.

Thus, stormwater itself contributes more BOD and COD than the highest possible

BOD and COD values for the product. This is a very conservative comparison,

because the measured values of BOD and COD for the applied, cured Entac material

is known to be high due to the effects of tumbling the mix for 24 hours, and due to the

fact that it was based on a 20 to 1 water-to-product ratio. In actual practice, the

product would be mixed only at the upper surface during a rain event.

Road surface runoff has also been studied by numerous researchers. Road surfaces

contribute BOD and COD from unburned petroleum, leak and/or blow-by of motor

lubricants, antifreeze and hydraulic fluid, transmission fluid leakage, use of

windshield liquids, as well as from tire wear, atmospheric deposition, animal and bird

feces, soil, paper, plastic and food litter, trucks hauling livestock and other materials,

and vegetative material including grass, leaves, pine needles, pollen and so on.

BOD data is scant but various reports show ranges in the 2 to 9 mg/g or 2,000 to

9,000 mg/kg range for BOD in dust/dirt on highways (Ontario MOT, 1991). Clearly

such dust and dirt is a major contributor of BOD from roads.

COD values for highway runoff were 16 to 660 mg/L (U.S. Dept. of Transportation,

1984) and 73 to 740 (average 268) mg/L (Lubbock, Texas) (cited in Ontario MOT,

1991).

If one assumed that the BOD/COD ratio was the same for these COD values as for

the Entac data (ratio of 1 to 2 approximately) the values would be (Calculated at 0.5 x

COD value):

Range Source

BOD range 8 to 330 mg/L U.S. Dept of Transport

BOD mean 169 mg/L U.S. Dept. of Transport

BOD medium rural roads 24 mg/L Driscoll

BOD medium, urban highways 75 mg/L Driscoll

BOD range 36 to 370 mg/L Lubbock, Texas

BOD average 134 mg/L Lubbock, Texas

The above data is cited in Ontario MOT, 1991.

Based on the above, the normal contribution of BOD from roadways and from

stormwater is greater than that from the Entac cured sample. The Entac data is also

higher than it would be under normal application and usage.


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4.2 Biodegradability

The BOD findings discussed above are supported by biodegradation testing carried

out on the Entac product. The standard test is the OECD 301D, Closed Bottle Test,

which is a 28 day test. The test was carried out by an experienced, accredited

laboratory, and the result of the testing was “Test item not readily biodegradable

(i.e., <60% degradation in 28 days”).

The test outcome is based on the amount of oxygen consumed after an acclimation

phase, and if more than 60% of material has degraded after 28 days, it is deemed to

be biodegradable. The Entac product result showed a steady but low rate of

degradation over the 28 day period, after which 27.5% degradation was measured.

If one assumed that this rate would remain constant throughout a full term to

complete degradation, the timeline would be about four months. In fact, Entac’s

experience is that the product can last more than two years in real world applications.

Applications on tailings fields, stockpiles, and road structures last on average one

year per coat of Entac. As the seal is built up in multiple coat applications the life can

be greatly increased, due to the efficacy and thickness of the seal and the fact that

atmospheric oxygen is not available to most of the product applied, as it is sealed off

by the top coat. The first coat locks the surface materials together and the additional

coats applied form the seal thickness, increasing or decreasing the longevity and

performance of the seal depending on the customer’s requirements.

This above information means that:

the product remains effective as a dust suppressant for relatively long

periods of time; and

over time it is completely biodegradable

The laboratory results for the biodegradability testing are attached as Appendix ___.

4.3 Conclusions Regarding BOD

The product is ultimately completely biodegradable.

In order to be effective as a surface sealant and dust suppressant the product

cures on a road or stockpile surface, so as to increase the longevity or the

effectiveness of the product.

BOD is only slowly released from the product, which means that it will not result in

a BOD “shock” or a large BOD loading in a short time frame.

The levels of BOD released by cured Entac product were tested using extreme

conditions including 24-hour tumbling, and the BOD levels are less than the


Ref. 1609 23019 March 2005 15

literature values for stormwater in various North American locations. In terms of

BOD loading, the Entac BOD levels are much lower due to very large volumes of

stormwater.

Similarly, the BOD levels obtained from aggressive testing were lower than the

BOD levels found on highway and road surfaces and runoff.

The use of Entac product is environmentally beneficial as it minimizes BOD

loadings because once cured its BOD is low, and it doesn’t release environmental

significant levels of metals, volatile organics or other undesirable materials that

can be found in other competing products.


Ref. 1609 23019 March 2005 16

5.0 ENDOCRINE DISRUPTING SUBSTANCES (EDSs)

The presence of endocrine disrupting substances (EDSs) in the environment has

become a matter of international concern over the past decade. There are now

numerous studies that indicate that the growth, reproduction and development of

some aquatic and terrestrial animals may have been affected by chemicals that

interfered with their endocrine systems.

Canada is a leader in addressing the EDS issue and it has had an action plan in

place since 1999. The first priority is to develop screening and testing

methodologies, and to identify various chemical families, and where possible

individual chemicals, believed to have potential as EDSs. To date, eight very broad

categories of substances have been identified as potential EDSs, including

polychlorinated compounds, pesticides, organotin compounds, alkylphenolics,

phthalates, natural hormones, synthetic steroids and phytoestrogens.

Phytoestrogens are toxins produced by certain components of plants and fungi, and

include compounds like genistein or coumestrol. It is uncertain whether any of the

phytoestrogens have been considered as priority items in Canadian research; a

review of the European Commission’s Endocrine Disrupters Website indicates that

phytoestrogens are not included in the list of 146 substances evaluated after the EC

compiled a candidate list of 553 substances.

Environment Canada’s Website indicates that the main source of potential EDSs may

be sewage treatment plants, as it has targetted a Montreal STP for EDS research on

the effluent discharged by the plant. This indicates that natural hormones and the

likelihood of finding larger quantities of EDS in pass-through medication and other

household items that end up being processed at STPs may be a higher priority at this

time.

The Environmental Choice Program Panel expressed concerns “over the linking of

various Pulp and Paper by-products with potential endocrine disruption”, and

requested more information on whether any potential EDSs are present in the tall oil

pitch (TOP) used in the product. Based on the literature and the ECP Panel’s

concern, it would appear that there are two main chemicals of concern over potential

EDSs from pulp and paper processes: polychlorinated compounds from the

bleaching of pulp in the process of some paper-making, and the phytoestrogens.

Polychlorinated Compounds

The tall oil pitch used by Entac Emulsions Inc. is from suppliers with no connection to

the use of chlorine bleaching in paper mills. As a precaution, Entac has been

extensively tested for PCBs, chlorinated phenols (among other phenol compounds),

and dioxins and furans.


Ref. 1609 23019 March 2005 17

None of these compounds have been detected in Entac’s product, and the analytical

testing was performed using the most sensitive analytical equipment commercially

available. As an example, the method detection limit (MDL) for dioxins and furans in

a recent test was 0.2 pg/g, which for each of the individual dioxin/furan congeners

resulted in non-detects at less than 0.02 pc/g in terms of toxic equivalents. This is

less than 20 parts per quadrillion, and is a testament to the skill of today’s analytical

chemist (in this case, the Research and Productivity Council Laboratory (RPC) in

Fredericton, New Brunswick). The total additive maximum possible detected toxic

equivalent level was 0.6 pg/g; Environment Canada's criterion, based on the NPRI

LOQ recommended by CCME is 9.2 pg/g. It should be noted that the latter values

are theoretical maximum levels calculated by assuming that some dioxin/furan is

present even though none was detected at these very low detection limits.

There is no analytical evidence that polychlorinated compounds are present, and if

they were, they would be present at levels at least 15 times lower than Environment

Canada’s guideline.

Phytoestrogens

Testing and screening for phytoestrogens has not yet been conducted on Entac. The

analytical methodology is not yet developed that would allow for such testing on a

regular basis on such a product, just as the methods aren’t available to routinely

determine EDSs in drinking water, or foods, or in the effluents from food processing

companies or other potential sources of phytoestrogens.

Entac has always been proud of its monitoring and testing program, and just as it has

been a leader in environmental testing of its products for chemicals of concern on

Canada’s Priority Pollutant lists, and for the numerous other compounds it has tested

for, Entac would like to be able to do the same for these emerging concerns, the

EDSs. It is expected that sufficient progress will be made on the development of

commercially available testing for EDSs once the screening and monitoring method

development being researched by Environment Canada is completed. When this

happens, Entac will be the first in its field to have its product tested.


Ref. 1609 23019 March 2005 18

6.0 SUMMARY

Entac products are designed to be effective at sealing roadways, stockpiles and other

surfaces, while causing no measurable environmental impacts due to the

environmentally benign make-up of the products and their constituents. The products

are manufactured from natural organic materials, and they’ve been intensively and

extensively tested for the complete range of organic, inorganic and metallic

contaminants, as well as for ecotoxicological impacts. No exceedances of any soil

criteria were measured, and no toxic effects of any kind were observed during the

testing.

Entac has been a leader in terms of product efficacy and environmental stewardship,

and continues to test their products to ensure their ongoing leadership remains in

place.

I trust that this document answers the questions raised in your December 9, 2004

letter and in our subsequent telephone discussions, and that based on this

information you will agree that Entac’s products are worthy of certification under the

Environmental Choice™ Program.

If you have further questions or concerns, please contact me.

Jim Bishop Date

Principal


Ref. 1609 23019 March 2005 19

7.0 REFERENCES

American Public Health Association, American Water Works Association and Water

Environment Federation. 1998. Standard Methods for the Examination of

Water and Wastewater. 20th Edition.

Makepeace, D.K., D.W. Smith and S.J. Stanley. 1995. Urban Stormwater Quality:

Summary of Contaminant Data. In: Critical Reviews in Environmental

Science and Technology, 25(2): 93-139, pp. 93-139.

Metropolitan Toronto and Region Conservation Authority (MTRCA). 1989. The

Manual for an Improved Lakefill Quality Control Program.

Ministry of the Environment (MOE). 1997. Guideline for Use at Contaminated Sites

in Ontario. ISBN 0-7778-6114-3.

Ontario Ministry of Transportation (MOT). 1991. Water Quality Management at

Highway Systems, A Literature Review. Volume 2 Operating Highway

Water Quality.

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