A COMPARISON OF THE EFFECTS OF 

UREA, POTASSIUM ACETATE, 

CALCIUM MAGNESIUM ACETATE AND 

SODIUM FORMATE RUNWAY 

DE-ICERS ON THE ENVIRONMENT 

Transport Canada Service de I'environnement et de soutien 

Airports SBcuritB et services techniques 

Safety and Technical Services ABroports 

Environmental and Support Services Transports Canada 
- 

GROUP 

October 26,1994 

Mr. Alee Simpson 

Transport Canada 

Environmental Review Services 

Place de Vilk 

Ottawa, Ontario 

KIA ON8 

AD1 Nolan Davis Inc. 

7020 Mamfotd Road, Hallfax, NS, Canada B3L IS9 

Ttl: (902) 453-5555 Fax: (902) 453-6325 

File No. 21-0059-154-1 

Dear Mr. Si Jd son: 

/ kt*. Re: Envimnrnentd Impsct of 

Ru nwav De-Seers 

We are pleased to submit five copies of a summary report of the results of the three 

evaluations of new runway de-iccrs that AD1 Nolan Davis has undertaken for Transport 

Canada, namely, potassium acetate, calcium magnesium acetate and sodium fonnate, against 

urea. This report summarizes the key information and recommendations. Details on the 

studies are contained in the three full reports on which this summary report k based. 

We would like to thank you and your associates for the cooperation generously offered 

throughout the project. 

Yours very truly, 

AD1 Nolan Davis Inc 

Roy D. John, BSc 

Chief Environmental Chemist 

Engineering, Consulting. Procurement and Project Management 

H.Iff.x, Sydney, St. Jobr 'r, Frederlctoa 
TABLE OF CONTENTS 

Page No. 

1.0 INTRODUCIION ............................................. 1 

1.1 Backntound .............................................. 2 

1.2 Study Site .............................................. 3 

13 Refemnces .............................................. 7 

2.0 ICmODOmGY ............................ 0. ............... 7 

2.1 Collection and Assessment of Existing Data ..................... 7 

2.2 Reconnaissance'and Site Selection ............................ 7 

23 Design of the Field Promm .......................... .. .... 8 

23.1 Soils Sampling and Testing Program .................... 10 

23.2 Surface Water Monitoring Program ..................... 10 

233 Groundwater Monitoring Program ..................... 11 

23.4 Soil Water Monitoring Progrsms ....................... 12 

235 Climatological Data ................................ 12 

2.4 Bioloaical Field Samplinn Procedures ........................ 13 

2.4.1 Artificial Substrates ................................ 13 

2.4.2 Soil Microbiology and Surface Vegetation ................. 13 

2.43 Surface Vegetation ................................. 14 

2.4.4 Quality Assurance ................................... 14 

2.5 In-house Laboratow Exmriments ........................... 15 

3.0 COMPARISON OF THE PERFORMANCE OF UREA, KA, CMA AND 

NaFo ...................................................... 15 

3.1 Site Designation ........................................ 15 . 

3.2 Backemund ............................................ 15 

3.2.1 ihe Acid Drainage Problem .......................... 16 

3.2 SOdiumLevels .................................... 18 

33 Impact of De-icer Chemicals ............................... 18 

33.1 Urn ............................................ 18 

33.2 CMA (Calcium Magnesium Acetate) .................... 19 

333 NaFo (Sodium Formate) ............................. 30 

33.4 KA ............................................. 32 . 

4.0 CONCLUSIONS AND RECOhfMENDATIONS ...................... 40 

4.1 Conclusions ............................................ 40 

4.2 Recommendations ....................................... 40 

Comparison Repon 

Runway De-ictts 

l'nnsport Canada 

Page i 

AD1 Nolan Davis hc. was contracted by Transport ha& to evaluate the environmental 

impact of three my de-iccrs, potassium acetate, calcium magnesium acetate and sodium 

formate at the Halifax International Airport between 1990 and 1994, 

A test program was devised whereby each de-iw was field tested and compared to urea, 

the de-icer in current use. Samples of shct and groundwater were dected routinely and 

at intends during stom events, when de-icer was being applied. The aquatic biology of 

nearby strm was investigated and a laboratory evaluation of the impact on surface 

vegetation, fungi and soil respiration rate was done. 

The results showed each of the new de-ices to be relatively benign and to have less impact 

on the environment than urea. 

AD1 Nolan Davis lac 214059-1561 
Comparison Report 

Runway De-iccrs 

Transport Canada 

Page 1 

This report is a summary of the studies which were undertaken to evaluate the 

environmental impact of three chemical de-icers proposed for use on airport runways. The 

studies include a the results of literature, field and laboratory investigations undertaken to 

establish the environmental impact of potassium acetate, sodium formate and dcium 

magnesium acetate as compared to ur& For operational considerations it is necessary to 

contact the Director, Engineering and Maintenance of Transport Canada's Airport's Group 

in Ottawa. 

To illustrate the results, only selected data has been used in this summary report. Fult 

detaii of the environmental research programs can be found in the contract reports 

"Environmental impact from the use of potassium acetate at Halifax International Airport," 

(AD1 Nolan Davis 19941, "Environmental impact ftom the use of sodium formate at Halifax 

International Airport," (Nolan, Davis 1992) and "Environmental impact from the use of 

calcium magnesium acetate at Halifax International Airport," (Nolan, Davis 1991). 

Every winter, major airports in the northern hemisphere are confronted with snow and 

fieezing rain conditions, which play havoc with airline schedules and compromise human 

safety. Striving to maintain safe conditions for the travelling public during the winter months 

poses operating problems for airlines and airport operators. 

To overcome these problems, airport operators apply cheraicals to aircraft, taxiway and 

runway surfaw. The chemicals are selected for their ability to prevent the formation of ice 

on aircraft and runways (anti-icing), or to melt ice and snow when formation has occurred 

(de-icing). There is, however, a down side to the beneficial use of these chemicals. World 

wide environmental awareness has focused attention upon the damage they impose upon the 

---- en!!rommtc - - - - - - - - - - - - - - - - - 

------ - - - - 

The chemical commonly used at Canadian airports on runways is urca The decay products 

of urea are nitrate, nitrite and ammonia Elevated ammonia concentrations can be tclxic to 

faeshwater organisms while the nitrates, in addition to promoting algal blmms, psc 

potential human health poblenrs 'Phe toxicity aspect of urea has rcsdtd in its ban at 

airports in several countries. The United States Environmental Protection Agency 

introduced tough regulatiom for storm water discharges which are aimed at regulating 

deicing fluid discharges. 
Comparison Report 

Runway Deicers 

Transport Canada 

Page 2 

The problems associated with the use of urea, have given rise to the development of low 

toxicity alternatives. Three such products are calcium magnesium acetate, potassium acetate 

and sodium formate. Calcium magnesium acetate (CMA) and sodium fonnate (NaFo) are 

applied in solid form while potassium acetate (KA) is sprayed in liquid form on my and

runway surfaces. 

Transport Canada decided to conduct a field test of KA, CMA and NaFo at an airport site 

which was considered to be representative of most Canadian airports, Accordingly, AD1 

Nolan Davis Inc. was contracted to assess the environmental impact of KA, CMA and NaFo 

versus urea at Halifax International Airport. The field tests also sought information 

concerning the operational capabilities of K& CMA and NaFo versus urea. 

Canada pioneered the use of granular urea as an anti-icing and de-icing material for airport 

runways on a large scale and it was adopted as the standard de-icing agent for runways and 

taxiways at Canadian airports about three decades ago. Urea was selected becaw it did 

not corrode aircraft parts (including aluminum), stain paints, or affect the plastic of aircraft 

windows. Urea, generally made up of at least 46% nitrogen, will melt ice at temperatures 

of minus 1$~ or higher. 

Environmental concern about the use of urea at Canadian airports began in British 

Columbia in 1971 and attention centred around possible eutrophication of downstream lakes, 

as proliferation of needs in the Okanagan lakes was already a concern. Studies at Penticton 

Airport found that applications of urea were roughly four times the normal agn'cultural rate. 

It was also noted that grass along runways grew better due to the nitrogen input from the 

urea. 

Studies at Kelowna Airport confirmed that ,the nitrogen content of snow adjacent to runways 

was highest near the runway and decreased considerably beyond about 30 m ffom the 

runway. Analysis of surface runoff from the Toronto Airport betyeen 1974 and 1977 

indicated that as much as 64 percent of th&d ureainitrogen appliqd entered surface water 

N~O& Y, - ... ... , , *, . I, . .. .-a , r i , ..*. .I 

L .. -. . c-I . '*.S ** .I . 2, 

...... 1- ...-..... Concern about glycol based de-iccrs is primarily assddiatd with their ~cePtiohy high 

oxygen demand. While the direct toxicity of glycol based de-icers to Guatic organisms is 

low, the potential reduction in dissolved oxygen in receiving waters could kill or stress 

organisms, particularly salmonoid fishes. 

AD1 Nolan Davis Inc 21 -0059-154-1 
Comparison Report 

Runway De-iotn 

Transport Canada 

Page 3 

Before any alternative can be considered for use as a de-icer, two operational criteria must 

be met Tbe material cannot be hazardous to the maintenance crew handling it in bulk at 

the airport. Also it must effectively work as a de-icer and meet the skid requirements of 

Transport Canada. 

KA, CMA and NaFo met the above criteria and laboratory data indicate they could 

substitute for urea (Fig. 1-1). It was then decided to research the environmental impact of 

the materials under field conditions, the focus of this executive summary report. 

13 Study Site 

In 1960, the federal government opened Halifax International Airport, located about 35 

kilometres north-northeast of Halifax and Dartmouth (Figure 1-2). Halifax International 

Airport (HLA) provides senices to centres in Nova Scotia, New Brunswick, Prince Edward 

Island, Newfoundland, Quebec and Ontario and to destinations in Canada, the United States 

and Europe. 

HIA straddles a physiographic divide separating the Atlantic Ocean and Bay of Fundy 

drainage systems. It lies in an undulating plain, which rises gradually fiom the Atlantic Coast 

to an altitude of about 153 metres at the northern boundary. The topographic expression 

wer the airport property is variable and is generally bedrock controlled. Topographic 

elevations over the site vary from 85 metres to 151 metres above mean sea level (AMSL) 

(MacDougall et al, 1963). 

The portions of the KA, CMA, NaFo and urea study areas which were located within the 

airport boundaries were generally unforested, whereas the monitoring and sampling areas 

located outside the airport boundaries were generally forested, mostly with softwood species. 

Figure 13 shows the general layout of the airport study area with the sampling locations 

marked. On the northeast side of the line dividing line running between tie Taxiway Delta 

and' Runway 15-33 (the urea study area) the water drains to the Atlantic Ocean. On the 

south west side of the line (the KA/NaFo/CMA study area) the water also drains to the 

Atlantic Ocean, but by a separate watershed.. h addition there are underd..tains on either. 

side of this line which conducts groundwater away fiom the centre of the taxiway - ~~nway. 

This means that the two study areas are close enough together to receive identical weather 

and it was hoped that possibility of cross contamination was not significant By using the 

experimental de-icers on the taxiway while retaining the proven urea on the runway proper 

there was no loss iA cafifidczm by tkpkts. - -- - -- - - 
CONCENTRATION, WT. % 

0 10 15 20 25 50 35 45 S( 

LEGEND 

---0- UREA 

- CMA DEICER ; .: ; . 

-I---' NUCI -, . : ' ' 

4 . .,;: 

- - - - - - --- SOOIUM F DRMAlE , . .__ I ...... -, 9 .'L 2. . - 

A AD1 Nolan Davis Jnc. 4#?9 Enzineering and 

Environmental Management Halifax, Nova Scotia 

-- -.- ..-. _ . . -- ". fl(;URE. -1-1- ......... 

FREEZING POINT DEPRESSION, OF' SIX. RUNWAY DFJCERS 
I 

fi 

OC~AN 

MIBS 30 0 30 60 

I 

A AD1 Nolan Davis Inc. &s;?g Engineering and 

Environmental Management Halifax, Nova Scotia 

FIGURE 1-2 

NOVA SCOTU 

2 
A AD

brs.R9 Bn

En

Ha
Comparison Report 

Runway De-ictrs 

Transport Canada 

Page 7 

13 References 

A substantial number of references were used in the Kq. CMA and NaFo studies. AU of 

these are included in the reference section of this report For the sake of clarity only the 

key references have been noted in this summary report 

Each of the studies were divided into three progressive phases of investigation. The first 

phase was the analysis of existing data, preliminary site reconnaissance and the design of 

field programs. The second phase encompsrssd field data collection and laboratory 

analyses. The third phase was the final compilation and interpretation of the data, 

development of the computerized database, and reporting. 

2.1 Collection and Assessment of Existing Data 

AU available information on the site, and on the use and environmental impact of KA, CMA 

and NaFo was collected and reviewed. (Sypher: Mueller 1989, and 1986, Elliot, 1987, Homer 

1988, Lumis et a1 1991 and McAUister 1981) Published and unpublished maps and reports 

on geology, hydrology, and hydrogeology were considered in the final design of the field 

program. 

2.2 Reconnaissance and Site Selection 

Once all of the available data were assessed, a site visit was undertaken to identify the 

KA/CMA/NaFo, urea, and control study areas, and to plan the soil, surface water, 

soil water and groundwater monitoring proams. During this initial field visit, detailed 

obsenmtions on geologic, hy&ogeologk mi!, terra. aaeq and surface drainage conditions 

were recorded and used in identifying the specific locations for the groundwater monitoring 

wells, soil water lysimeters and surface water monitoring stations. Based upon this site 

reconnaissance it was decided that the K#UChfJb+NzrF~ study area would be located at 

Taxiway Delta and the mea study ares lwatcd tit the adjacent Runway 15-33 (Figure 1-3). 

It was anticipated that se~:uriv a?ld ~perationd (access) restrictions would be less within the 

selected area, because Runway 15-33 was a secondary xunway to Runway &24, 
Comparison Report 

Runway De-ictrs 

Transport Canada 

Page 8 

For the control study area, a small subwatenhed system, which is a tributary to Johnson 

River, was selected (Figure 2-1). The headwater reaches of this brook originate in a low 

lying wetlands area within the forested, southwest quadrant of the airport property. It was 

considered unlikely that this area has been influenced by the use of de-icers at the airport. 

An additional advantage was the presence of existing baseline data for the brook. 

23 Design of the Field Program 

The field program was designed to include the following: 

1) monitor meteorological conditions; 

2) characterize surface runoffs - quantity and quality 

3) determine soil physical properties and evaluate soil microbial activity; 

4) determine groundwater chemical properties; 

5) characterize surface water quality of receptor stream, river, lake, or pond and 

assess the effects of mning and standing water on aquatic biota. 

Throughout these programs sufficient samples were collected to ensure statistical and 

reasonable confidence levels. 

Monitoring was also carried out during storms. The ideal storm was one that involved first 

freezing rain that later developed into rain. This meant that chemicals would be used as an 

anti-icer or de-icer and there would be a subsequent good flush to the nearby watersheds. 

Selecting the best storms to monitor was difficult. While weather predictions for the next 

2 to 3 days are generally good for most purposes they are too imprecise for efficiently 

mobilizing a field crew. Careful coordination with the airport staff improved the situation 

but there were still problems. Some stoms dwindled markedly before arriving in Nova 

Scotia, some were delayed and therefore occurred during warmer time periods, and some 

brought rain or snow instead of freezing rain. 

The surface water program was designed tci monitor contaminant concentrations adjacent 

to the application surfaces as well as the 'effect of downstream attapuation. In areas where 

there might be some overlap in the influences of the two components (urea and KA, (=MA 

or NaFo) samples were *dl@ 'for .tfirs~&ipacts'oE bath ,wea.md. JCA, CMA or NaFo, ' 

. - . - .' . * ?- . &*,Y ; .- -. .. - * , , 

The locations of the soil water lysimeters and groundwater monitoring wells were deigned 

to be as close as possible to, and within the flow paths leading from the application surfaces, 

but outside of operationally restricted areas. For example, due to restrictions imposed by 

- -- . - . C . .. . ,. __. 

AD1 Nolan Davis Inc 218059-154-.I 

Comparison Repon 

Runway Deicers 

'bnspon Canada 

Page 10 

snow clearing requirements, the installations within the Urea study area had to be greater 

than 15 metres (50 feet) from the active runway surface; and within the KAI CMA/NaFo 

study area, greater than 9 metres (30 feet) kom the taxiway surfacc 

Field personnel could not work within 46 metres (150 feet) of the tarmac, unless an escort 

was present who could maintain contact with the air traffic control tower. Since the soil 

fysimeter monitoring well installations and surface water monitoring stations had to be in this 

zone, escorts were essential during all field activities. 

For the control area, the ldcations of the surface water monitoring stations, roil water 

fysimeter, and groundwater monitoring wells were selected to emulate sampling locations at 

the other study areas as much as possible. 

23.1 Soils Sampling and Testing Pmgram 

Soil samples were collected to test their physical properties prior to, and after, the 

application of de-icers. Three soil samples from each study area were tested for their 

physical properties (i.e grain sizc, Atterberg Limits, and moisture content). In addition, roil 

samples were collected and subjected to greenhouse tests to determine soil microbial activity. 

(See 24.2) 

As in-situ testing proved impractical, soil permeability was examined theoretically (HazenWilliams method) using grain size analysis of the soil samples collected. 

23.2 Surface Water Monitoring Program 

Wherever possible, established Transport Canada (TC) monitoring stations were used during 

this study, thus providiig a continuous database for the evaluation of historical trends. 

As noted above, three study areas were selected for the field test of the e&ronrnentaJ 

impacts and of KA/CMA/NaFo and Wea. These included a control stream (control) 

draining the southwest corner of the HaUax International Airport complex, a stream (Leech 

Brook) draining part of Taxiway,Delta to which KA/ CMAlNaFo was applied as a de-icing 

treatment during the studj @A/CNM/N$FO stream); and Miller Brook (urdrains the eastern portih of RunwaF 15-33 to which urea was applied as a de-icing 

treatment. A ditch rmvng nmoff'frorn the Tadway Delta subdrains (Station R1) in the 

KA/CMA,/NaFo treatmerit area was also sampled. 

AD1 Nolan Davis Inc -21-0059-i%1 

. , .. 
Comparison Repon 

Runway De-iccn Page 11 

Transport Canada 

Within the KA/CMA/NaFo study area, the surface water monitoring (measurement of flows 

and collection of water samples was done at 8 stations (see Figure 1-3): Within the urea 

study area, the surface waters 1 ere monitored at 4 stations (see Figure 1-3): 

Two surface water monitoring stations were established in the control study area. Significant 

surface flows only occur during, and for a short time after, precipitation events. Therefore, 

whenever possible, the sampling events were adjusted to follow major precipitation events. 

The water samples were tested in the field for pH, conductivity, temperature and dissolved 

oxygen content. 

Given the nature of typical winters in the area, it was anticipated that major precipitation 

or snowmelt events might occur over the course of the winter. Therefore, storm event 

monitoring was undertaken as a component of this project. Three freezing storm events 

were monitored during all yean of the study. Monitoring was conducted prior to, during, 

and after, the storms to establish pre and post-storm trends. 

Surface runoff and stream water samples were collected, flows measured, and meteorological 

conditions monitored, over the duration of the storms and continued into the storm recession 

period. Groundwater and off-site surface water stations were monitored prior to, and after, 

the stonn event. 

The water quality data and flow measurements collected during the storm events were used 

to define the variation in contaminant loading rates throughout the storm cvents, as well as 

hydraulic loadings which were entering the site receptor streams. 

233 Groundwater Monitoring Program 

The data review suggests that the bedrock is the major aquifer and the upper hctured zone 

is the mast important location for monitoring well installation This zone represents a 

potential quick release pathway for contaminants to leave the site, since it generally has the 

highest groundwater flow velocity with the least attenuation of contarninants. 

The relatively impermeable nature of the till, suggested that the pkntid rate of 

contaminant migration within this unit would be relatively minor, and that a significant . 

amount of attenuation would Wrcly occur along tbe ~~~rkvates flow path As e result, the 

till was considered to be a less likely source d ~n~~~mCgrtitibn and, therefore, a Jess 

important target for monitoring wells. 
23.4 Soil Water Monitoring Programs 

An attempt was made to the characterize the unsaturated soil zone by collecting soil water 

samples using tube-type suction lysimeters. Within both the KA/CMA/NaFo and urea study 

areas, lysimeters were installed in three locations (Figure 13) in the vicinity of the 

groundwater monitoring wells. The soil water samples in the lysimeter tubes were collected 

with a hand pump. Samples were collected from the lysheter tubes with a syringe and were 

tested in the field for pH and conductivity. Soil water samples could only be collected 

whenever it was not frozen. .... 

'3 >.- - ... 

-- -.,.. . .... - -'*.'.=. -4 .,. Daily meteorologi&l data (pr~dpita~o~,'~$& sj&l: inid direction, temgkratyriix were 

obtained from ~nvironm&t-enada's ~@os~heric'~n@onme~ . , ,. Service (AES) station at 

the Halifax Airport, over the duration of the study. 'these data were supplement~d by 

observations made by field personnel during the field prograia 

AD1 Nolan Davis Loc 21-0059~1563 
Comparison Report 

Runway De-ices 

Transport Canada 

Page 13 

2.4 Biolonical Field Sampling Procedures 

Biological components which were examined on the three streams being monitored were 

phytoplankton, periphyton, and benthic macroinvertebrates. 

Water temperature and pH were measured at each site and samples were taken to 

determine the chlorophyll g. Samples were also taken for phytoplankton cell counts at two 

sites on each of the test streams. 

Samples of benthic macroinvertebrates were taken on each sampling occasion. Samples on 

flowing water stretches with gravelly bottoms were sampled with a Surber Sampler. 

Substrate was loosened and freed of organisms and captured in the attached net Muddy 

bottom or pond environments were sampled in triplicate with a Ekman Grab. Samples were 

sieved to eliminate fine sediment and then preserved in formalin. 

2.4.1 Artificial Substrates 

Artificial substrates, consisting of plexiglass plates, were placed to give a standardized 

measure of microscopic plants growing on surfaces in the stream. Plates were replaced in 

midoFebruary and mid-March and removed in mid-April. 

2.4.2 Soil Microbiology and Surface Vegetation 

Two sets of soil core samples from each of the K& CMA and NaFo, urea and control sites 

were collected in each of the study years. 

Five core samples 7.5 cm in diameter and 10 cm in length were cokted from the corners 

and centre of each of three 1 m2 plots at each site. The samples collected in March were 

obtained from locations which overlapped those from which the core samples were obtained 

in November of the previous year. Prior experience has shown that this soil sampling 

pattern yields excellent reproducibility of subsequent chemical and biological snalyses. 

These composite samples were used for the analysis of bacteria and fungi and for the 

dctemination of soil respiration rates. -, 
Comparison Report 

Runway DGicen 

Tnnspon Canada 

2.43 Surface Vegetation 

Sixteen blocks of soil samples, collected from the KA/cMA/NaFo study area, were placed 

in plastic trays, in a light and temperature-controlled greenhouse. Water was applied at two 

thirds the annual precipitation rate of the Halifax International Airport to simulate 

precipitation during the months of late autumn, winter and early spring. A light regime of 

12 hours on and 12 hours off was employed, and the temperature was regulated to always 

be greater than 65' F. KA, CMA or NaFo was applied either bi-weekly with the irrigation 

water to eight block samples at concentrations ranging from 0 to 5000 mgR, or in a single 

application to each of eight Hock samples at concentrations ranging from 0 to 5000 mg/kg 

of the dry weight of soil. The procedure was designed so that, at the end of the evaluation 

period, both pairs of test blocks would receive comparable mass quantities of de-icer. A 

seventeenth block was used to determine the moisture content and bulk density of the soil 

The concentrations of de-icer used in these tests ranged from the most probable 

concentrations to be encountered (0-500 ppm) to those greatly in excess of those likely to 

be encountered (1OOeSO ppm), whether these were applied over a ten-week period or all 

at one application as would occur in a reagent spill. In both tests, the total amounts of deicer applied were similar, allowing the evaluation of the differences between application over 

a period of time and one large, possibly catastrophic, application. At the end of the tenweek growth period, the surface vegetation was harvested, dried to a constant weight at 85% 

and weighed. 

2.4.4 Quality Assurance 

Quality control procedures were instituted for the field sampling and the analytical programs. 

This included the collection and analysis of blind duplicates and blanks, blind spiked samples, . 

trip blanks, field blanks and equipment use blanks. 

A field procedures manual was developed as an integral component of the field program 

design. The manual defined field procqlvres, sampling- protocol, and quality assurance 

procedures for the study. In addition, sampling record sheeti were developed which defined 

data collection requirements. A chain of custody. .form w& - also developed which 

accompanied each group of samples. 

a1 Nolan Davis Inc '21-0059-154-1 
Site Designations 

Site Designation . . 

3.2 Background 

Urea Study Site - Surface Water Station 

Control Study Site - Surface Watcr Station 

Test Deicer Study Site - C-CMA 

F-NaFo Surface Water Stations 

K-KA 

Monitoring wells - all sites 

Biological Stations 4 

The effects of the three deicers must be considered in the light of an acid drainage problem 

and high sodium level situation at the Airport. . - 

AD1 Nolan Davis Inc 218059-1541 
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Runway Deicers 

Transport Canada 

Page 16 

3.21 The Acid Drainage Problem 

Some parts of the airport are built on areas of pyritic shale (Stea and Fowler, 1981). During 

construction these were exposed and, in places, extensively fractured. Pyritic minerals, in the 

presence of air and moisture, will very slowly oxidize to sulphuric acid. As the soil moisture 

becomes acidic it creates ideal conditions for enhanced bacterial activity. Species, such as 

Th.iobacillus ferrorddans can use the free energy generated by the oxidation and thereby 

promote the oxidation rate. This in turn raises the temperature and results in an even faster 

oxidation rate. 

Some period after the initial exposure, usually a few years, the acidic production rate reaches 

an equilibrium value. By then severe environmental damage is apparent. Surface streams 

look barren and frequently have deposits of iron precipitates on rocks and vegetation, 

aquatic life is killed or driven away. 

The limiting factor for this reaction is the availability of oxygen although the rate is also 

affected by temperature. Typically there is adequate oxygen down to one to two metres 

below the surface of unsaturated soil. So acidic production can continue at depth even when 

the surface is fkozen. 

Sulphuric is a strong inorganic acid and it readily dissolves metals such as iron and 

aluminum. During the tests, the presence of these metals in the surface and groundwater 

samples was more easily related to the anticipated acid generation tben to the presence of 

any of the de-icen. For example in the control surface waters of NDB-1 (Figure 3-1) iron 

- - 

and aluminum levels drop as the temperature drops and acid production slows. At the same . - - - - time pH ti-, x~lphate drops; as apctcd- l''breyt~~e occurs inthe spring, -This - 

pattern is generally followed throughout the test area and can be seen in Figure 3-2 and 

shows that many sections of the airport are effected by exposure of slate during the initial 

airport construction. Groundwaters follow a similar trend as shown by the results for two 

monitoring wells in Figure 3-3. Similar data were collected for the KA study during the 

1993-1994 season 

.> .. ... -. ..-. . . - 
Station NDB-1 

Regular Monitoring 

I ~nhronrnehd Management 

Halifax. Nova Scotla 
Station NDF-1 

Regular Mocrirori~ 

Station NDF-1 

Regular Monitoring 

Station NDU-2 

Regular Maocing 

Station NDF-1 

f3egular Monitoring 

Station NDU-2 

Regular Monitoring 

A -=" AD1 Nolan Davis Inc. eQq ~&ineerin~ and 

Environmental Management 

Halifax, Nova Scotia 

. - , 

FIGURE 3-2 

NaFo AND UREA YONlTOFUNC STAnONS -h91/1992 . .I: I.. 

. , 

. . 
Station MW-2 

Regular Monhing 

l Station MW-2 

Regular Monitoring 

Station MW-3 

Regular Modtorlng 

Station MW-3 

Regular Monitoring 

station MW-2 

Regular Monitanng 

Station MW-3 

Regutar MonUoring 

A =@ AD1 Nolan Davis Inc. 6'~$ Englneerinz and 

~n;ironmental Management 

Halifax. Nova Scotia . 
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Runway DGictrs 

Thansport Canada 

Page 18 

3 Sodium Levels 

There are three sources of sodium at this airport. First, the native soils contain a wide range 

of sodium levels. This source will provide a flush in the spring both from material dissolved, 

but relatively immobile in the winter and fkom erosion due to the spring nm4. 

The second source is the sea. HIA is just over 30 ID from the Atlantic Ocean. The nearby 

coastline is directly in the path of easterly gales which can run the full fetch, unobstructed, 

from Ireland. The violently pounding surf shoots a finely divided spray high into the air, and 

the gale force winds drive it inland. 

The last source is road salt (sodium chloride), a de-icer that is used on all roads around the 

airport. Vehicles used by airport maintenance and security travel on the roads and taxiways 

and cakes of ice and salt form on wheels and the undersides of the body and these can be 

transported onto the taxiway. 

The influence of road salt is clearly seen in the background stations, NDB-1 and NDB-2 

(Figure 3-4). These are just downstream of a public road that is salted during the winter. 

The figure shows the changes in sodium concentration as it relates to the major storms. 

The relationship with the road salting program is evident. 

33 Impact of De-icer Chemicals 

The results of the monitoring programs were used to evaluate the impact of the de-icer 

chemicals on various components of the local environment The level of impact was 

assessed against the values obtained at the control stations (ie. background values or thosc 

unaffected by the de-icen chemicals, though not necessarily other airport effects) and typical 

data from other appropriate studies. Interpretation against these standards was sufficiently 

obvious that no attempt was made to statistically evaluate the data. The 4 mg/L ammonia 

criterion is useful at this site only. It was chosen as a within-theairport control Jew1 that 

was baed on the sensitivity of local species and the potential for dilution at the airport 

b~und~j. - r ._ . L 

' a, 

33.1 Urea I 

.- ,,. 

w- . -.. . 

Urea is an arnide of &bo& acid and contains 47 percent nitrogen by weight. It is a solid 

crystalline substance that depress the freezing point of water down to about -100C (see 

Figure 1-1). Urea is very soluble, evenk cold water- (459 g/L at OC). 

- A, , AD1 Nolan Davis Inc . . 21-0059-lSl 

$ r 
Station NDB-1 

Regular Monitoring 

Station NDB-2 

Regular Monitoring 

A AD1 Nolan Davis Inc. 

ewq Engineerin~ and 

Eo%ronrne6.t~1 Management 

Halifax. Nova Scotia 
Station NDU-2 

Regular Monitoring 

Station NDU-3 

Regular Moniton'ng 

Station NDU-2 

Regular Monitocing 

Station NDU-4 

Regular Monitoring 

.... -@. AD1 Nolan Davis Inc. PWq , Engineering and 

Environmental Management 

- ,.# 

Halifax, Nova Scotia . 

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Comparison Report 

Runway DGiars 

Transport Canada 

Page 19 

The impacts of urea have been well known for some time. The key concern is with the 

breakdown product, ammonia which is toxic to fish at low concentrations. For this site an 

alarm level of 4 mgL was chosen as thiswould not cause problems with the impoverished 

and tolerant fauna on the airport proper and would be diluted by the time it reached off-site 

locations. These studies were not intended to significantly add to the knowledge of urea, but 

instead it was used as a yardstick against which the other de-icers could be compared. As 

expected, after the application of urea, ammonia levels rose, often above the level of 

concern. This is clearly seen in Figure 3-5, which provides examples of results £rom three 

surface water monitoring stations. 

Ammonia was also measured in samples ffom the KA/CMA/NaFo test site. This was trad 

to a flow of groundwater from a taxiway underdrain which emerged at station NDCjF 3. 

Surface water systems downstream of this point also have high ammonia levels itquentty 

exceeding the 4mgL level (Figure 36). Upstream the levels are below l6mgL Because 

neither KA,CMA nor NaFo can form ammonia, it is readily apparent that the source is urea 

It also indicates that, given the necessary subsurface conditions, urea-generated ammonia can 

travel widely and pollute several surface water systems. 

33.2 CMA (Calcium Magnesium Acetate) 

CMA is an illdefined compound of calcium magnesium and acetate. Each molecule has 

three to six calcium ions and six to seven magnesium ions. It is an off-white powder that can 

lower the fieezing point of water to about -30°C (see Figure 1-1). The commercial product 

is supplied as round pills, about two mm in diameter. CMA breaks down carbon dioxide 

and water. The CO, is trapped in water to fmm. carbonic acid which can form salts with 

calcium and magnesium. None of these breakdown products would be the cause of concern 

except in massive quantities. 

In general CMA had little or no impact on water chemistry. At HIA it might even be 

slightly beneficial, as it helps to reduce the acidity somewhat. 

From Figure 3-7 it can be seen that acetate concentrations increase in surface water during 

the winter and decreases in the spring, changes which coincide with the application times of 

CMA The levels generally do not go above 10 mgR, probably related to the fact that 

acetate is easily biodegradable. Changes in aidurn and magnesium levels are not as well 

correlated to CMA application and correspond more closely with the background chemisy. 

In Figure 3-8 NDC-2& NDC-3 and NDC-S show calcium and magnesium lewels that 3-2 

AD1 Nolan Davis Inc 21-BlbSSa-Wl 
NDC-3 

Regular Monitoring(1) 

Station NDF-3 

Regular Monitoring 

- 

Station NDF-4 

Regular Monitoring 

- .. 

A ma'@ ADI Nolan Davis Inc. Gwq Eneineerinr and - - 

~ncironmehl Management Halifax, Nova Scotia 

-- . .-* . . . 

FIGURE 3-6 . - 

AMMONIA UWEU 

AT CYA AND NaFo STATfONS 
Station NDC-2A Station NDW 

Regular Monitoring Regular Monitoring 

1- 

Station NDG3 

Regular Monitoring 

Station NDG5 

Regular Monitoring 

A --=" AD1 Nolan Davis Inc. 

awq Eqineering and I FICU RE - 3-7 

ACEX'ATE RESULTS -AT C3dA STA193NS Environmental Management 

Halifax. Nova ~cotia- I 
Comparison Report 

Runway Deiars 

Transport Canada 

Page a 

decrease slightly in mid-winter and rise in the fall and spring. However, this pattern is also 

true for the urea side (see NDU-2). The background values, NDB-1 and NDB-2, only 

marginally follow this sequence but note the concentrations in all samples are similar. This 

information suggests that the acid production and metal dissolution, which is more seasonally 

dependant, is a likelier explanation for the calcium and magnesium levels (and other metals 

too). 

During the storm events the leading data showed that a slug of reagent moved through the 

area, generally with a peak at around 24 hours after the onset of the storm (Fig. 3-8). The 

peaks for calcium and acetate, return rapidly to more baseline levels. Ammonia, £rom 

contamination from urea, also rose sharply and then feL In the January 1618,1991 storm 

(Figure 3-9) the iron and aluminum levels do not change noticeably. This was expected from 

other research. During the February 19-21, 1991 storm, however, iron and aluminum 

followed the same trend as calcium and magnesium and showed a good correlation with the 

CMA application (Figure 3-10). The most likely explanation laid with the nature of the 

stom themselves. The first storm occurred when there was a large runoff due to melting 

of snow pack In the second storm there was less runoff due to a minimal snow pack This 

was reflected in the loadings. There may have been a mwement of metals in the first stom 

but this was not easy to detect because of the dilution due to runo& Because the mwement 

of calcium and magnesium was twice that of the other metab (as seen in the second storm) 

the loading for these two metals were less masked by dilution in both storms. 

A limited investigation of the biological impact of the CMA treatment found no effects on 

phytoplankton, periphyton or macroinvertebrate abundance. This was also true for the ureaimpacted streams. Both periphyton and phytoplankton were low and stable at all sites 

Although no large differences were observed for macroinvertebrates it is possible small 

changes are missed due to the high variability in macroinvertebrate numbers. 

CMA did not affect the in-situ concentrations of bacteria (either anaerobic or aerobic, 

psychrophilic or mesophyllic). Similarly it did not have an impact on either psychrophilic or 

mesophyllic fungi. This was supported by the unchanged soil respiration characteristics. 

Vegetative growth was only affected above , hi-weekly ps.j'.e application rates of 1000 mgh or single 

applications of 169 urn2. A single application of 845 g/m2 stopped all plant growth. Such 

high levels would not normally occur, unless pure reagent was dumped direaly on the 

ground during a spill. 

AD1 Nolan Davis he. ' . I* .. 21-0069-154-1 

1 

It:. > 
Station NDG2A 

Station NDC-3 

Station NDCd 

Station NDU-2 

Station NDB-1 

20- 

18*, n 

Station NDBP 

A =' AD1 Nolan Davis Inc. ew9 Engineering and 

Envirsnmeutal Mmanrement I 

Halifax, Nova ~cotia- . I 
A -lo AD1 .Nolan Davis Inc. mRq ~n~ineeiik~ and 

Environmental Management 

Halifax, Nova Scotia .... I,.. . 
Station NDC-4 - Loading 

StormTebruary 19-21 .I 991 

Station NDC-4 - Loading 

A =" AD1 Nolan Davis Inc. t((r?wq Engineering and . , 

Environmental Manaeement 

RCW 3-10 

FEBRUARY 19-21, !B91 SrORU XBADINCS 

AT STATION NX-4 

Halifax. Nova ~cotia- - I 
Comparison Report 

Runway Deicers 

Transport Canada 

333 NaFo (Sodium Formate) 

NaFo is the sodium salt of formic acid. It is pure white crystalline powder that can lower 

the freezing point of water to about -16T (see Figure 1-1). The commercial product is 

supplied as a crystalline, angular pellet one to four rnm across. NaFo is considered a good 

food source for bacteria and breaks dorm to CO, and water with the release of sodium. 

h general NaFo also had little or no impact on water chemistry. Concerns wer the increase 

in sodium were diminished because it is difScult to discern the effect of sodium addition 

against the existing, large background fluctuations. The background samples have levels of 

20-80 mg/L prior to any salting and this rises to 140 to 180 mg/L after the use of salt on the 

nearby road (Figure 3-4). A similar pattern but generally at lower levels was seen for the 

sodium formate stations (Figure 3-1 1, NDF-2A and . NDF-3). Station NDF-5 was 

downstream of the road that impacts NDB-1 and 2 and the road salt contribution was again 

evident. 

The sodium variation on the urea side was still visible but less pronounced. Station NDU4 

was again downstream of the road and was clearly salt contaminated 

It was clear then that, while sodium formate did contribute some sodium to the surface 

waters, it was not the sole nor the major contributor. 

Fonnate was difficult to detect in most samples. Only 14 per cent of the samples analyzed I had a detectable level of formate and only 4.5 per cent had a value greater than 1 mgL 

Out of over 100 samples there were but two significant values (20 and 38 mgh). This 

suggests formate is not an important or persistent contaminant 

Sodium and formate concentrations rose after the application of de-icer to the runway. 

Formate often proved difficult to detect and this could be due to a limitation of the 

analytical method. It was difficult to obtain a standard, but every effort was made to ensure 

reliable results. Sodium analysis was a lot simpler and was well established. It was easy to 

follow the changes in sodium level. These may not all be attributable to sodium formatc 

Each storm event did increase the run-off and would therefore flush any mobile sodium. 

Such a flush would follow the same pattern. It was much more likely, however, that the . 

major portion of the sodium increase comes ftou de-icer. 

AD1 Nolan Davis loc 21-9-154-1 . ... 

, , 
Station NDU-2 

Regular Monitoring 

Station NDF-3 

Regular Monitoring 

Station NDU-3 

Regular Monitoring 

Station NDF-5 

Regular Monitocing 

Station NDU4 

Regular Mmitocirrg 

A -me AD1 Nolan Davis Inc. qwq hgincerln~ and I 

En&onrne6t.l Management Halifax, Nova Seetia I 
Comparison Repon 

Runway De-icers 

Transport Canada 

Page 32 

However, during storm events, as with ChM, slugs of NaFo reagent also appeared to move 

through the watershed. This was more difficult to evaluate as the results were compounded 

by the presence of local sodium and the difficulty of detecting formate, as indicated above. 

Assuming the results were at least partially due to NaFo additions then the material took 

more time than CMA to peak at the monitoring stations 

The pattern indicate the de-icer moved through the environment with a peak at various 

times up to four or five days after the beginning of stom This was longer than expected 

based on the CMA experience. However, the concentrations in the surface water system 

normally remained low, with sodium for example usually around a few mg/L 

The impact on other soil constituents was hard to define as it was complicated by the 

background chemistry and the change in flow regime caused by the storm. A number of 

variables do change in apparent response to the influx of NaFo, but these changes are minor 

(a few percent). overahthe impact of NaFo was low and was lost to the area within a few 

days. 

The limited biological study found no effixt of the treatment on either the test streams 

receiving NaFo in terms of phytoplankton, periphyton or macroinvertebrate abundance. 

Also, no effects were observed on the in situ concentrations of bacteria or fungi. The roil 

respiration characteristics were also unaffected. Bi-weekly applications of NaFo in ucw 

of 3500 mg/L did inhibit plants. Single applications of 85 g/m2 caused a 50 per cent 

inhabitation. Above 850 g/m2 there was almost total inhabitation of growth. 
Comparison Report 

. Runway De-icers 

Transpon Canada 

Page 33 

KA is the potassium salt of acetic acid, made by reacting potassium hydroxide and acetic 

acid. It is a white deliquescent powder that can lower the freezing point of water to d8"C 

The commercial product is supplied as a 50 percent solution, usually with corrosion 

inhiiitors and an identifying dye. Acetate ion can be broken down by bacteria but is more 

stable than formate ion (that is less readily used as food by the bacteria). 

During the first storm event acetate was only detected at NDK3. Here the levels were low 

and erratic, with separate peaks at 12, 19 and 24 hours. These appear to relate to the rate 

of precipitation. There was a good correlation between the increase in flow rate and the 

increase in acetate level (Figure 3-12). As the flow rate dropped so did the acetate level, 

indicating the decrease in physical flushing, similar patterns occur during storm event 2 and 

3. 

Because of its location, NDK-3 often shows the highest concentrations of a particular 

variable. It was believed that this was due to this station receiving a combined runoff from 

both the Tadway Delta and the underdrains. 

Downstream of NDK-3 (at NDK-4, NDK-5 and NDK-6) the brook received more runoff 

from areas not impacted by KA and was usually lower in K due to dilution. Howmr, when 

the precipitation rate was high enough to produce a flow in the road side ditch at the end 

of the taxiway (NDK2A) then there was rapid flush of de-icer, giving increased levels at 

NDK2A and NDK4. 

This is not entirely consistent and the explanation may lie with the erratic flow behavioun 

of NDK2. The zone around NDYd often floods and the surface has been seen to flow 

northeast and southwest. T%is meant acetate would be flushed away from NDK-3 and NDK4, at least for a period. 

The most illustrative example was stom No. 2 Acetate was detected at all four NDK 

stations. A large initial ihsh pushed acetate thraugh NDK2 and NDK2k Flows and 

acetate levels are more emtic dwmtrearn bob &a"il.skw m tendency towards an initial flush 

followed by a decrease of acetate (see Figure 3-13). 

The hypothesis that acetate was removed by dilution and dispersion, rather than degradation 

was supported by laboratory experiments. Tests with typical airport runoff water showed 

that it did not degrade unless fertnized with phosphate and possibly ammonia. 
Station NDK-3 

Storm Monitoring Event No. I 

Station NDK-3 

Storm Monitoring Event No. 1 

A AD1 Nolan Davis. Inc. - QR4 Engineering and 

Environmental Management Halifax, Nova Scotia 

.. ___ FIGURE 3-12 

EOMPARISON OF ACETATE AND FXDW RATE 

HALIFAX INTERNATIONAL WRPQRT - - 
Station NDK-2 

Storm~gEverrtNo2 

I 

Station NDK-2A 

Stonn Moniton'ng Event No.2 

0J. 9: ::GJ 

100 ms abb 470 570 7s mol01017w~~ 

Ti (minut.8) 

Station NDK-3 

Storm McmItoring Event NO2 

+ Acetate 

A AD1 Nolan Davis Inc. I FIGURE 3-13 

Engineering and ACETATE LEWIS DURING A SrORM EVENT 

Environmental Management IMUFAX DITERNATIQNAL MRPORT 

Halifax, Nova Scetia - 
Comparison Report 

Runway De-ictrs 

Transport Canada 

Page 36 

The use of KA did increase the BOD, significantly at the NDK stations. Figures 3-14 and 

3- 15 show the BOD, levels at two stations, NDK-2 and NDK-3, during two storm events. 

As the normal BOD, levels during the previous s~dies and at other sites during this study 

was typically less than 10 and frequently less th& 5 mglL then results from 5 to 70 were 

surprising. Figure 3-16 depicts regular monitoring data from NDK-4 and NDKd and sham 

how closely the BOD, is related to acetate levels. This could be directly compared to the 

CMA data. Again there was a dose correlation but the levels are substantially lower. 

While it is clear that ICA increases the BOD5 the cause was hard to define. In the airport 

conditions, the KA does not degrade in the normal residence time in the surface water 

system. Although potassium acetate is a chelating agent, there was little evidence that the 

bulk was remaining on site and reacting. It was possible that the excess caustic, present in 

the commercial product, temporarily increases the pH causing an increase in bacterial 

activity in other materials in the soil and water. It was possible that a residual amount is 

being absorbed into the interstices of the runway an reacting with a mway component or 

con taminant. 

The products of this reaction were flushed with the following storm event and result in an 

initial high BOD, which drops with the. Whatever the mechanism the increase in BOD, 

was strongly correlated with the acetate levels. The BOD, levels measured arc equivalent 

to a stream polluted with untreated sewage. However, it must be remembered that the 

impact at HIA will not be as severe as the results would indicate, as the BOD, measurement 

is done at lS°C. Typical water temperatures at HIA in the winter are just above (PC so 

biological activity is retarded.' By the time the water temperature was high enough for 

sigmficant biological activity it would be long after the season of de-icer use. At other 

airports this may be a more important consideration. 

A limited investigation of the biological impact of the KA treatment found no effects on 

phytoplankton, periphyton or macroinvertebrate abundance. Thic was also true for the ureaimpacted streams. Both periphyton and phytoplankton were low and stable at all sites 

Although no large differences were obs.e~~ed for macr0invertebrat.a it is possible smaU 

changes are missed due to the high va@ib@g-jn macroinvertebrate ..___. __ numbers. ..-_ 

KA did not affect the in-situ conceitfiiid11~ of 'bacteria (either .anaerobic or aerobic, ' 

psychrophilic or mesophyllic). Similarly if did not hawas impact on either psychrophilic or 

mesophyllic fungi. This was supported k$ the ~nchangid soil respiration characteristics. 

-'. . I AD1 Nolan Davis Inc , . 

. . 21 -0059-154-1 
Station NDK-3 

Storm Monitoring Event No.2 

A lo AD1 Nolan Davis Inc. 

engineering md 

Enviroarneita% Management Halifax. Nova Scotir 
Station NDK-2 

Storm Monbhg Emit No.1 

Station NDK-2 

stm Morritoring €vmt Nos 

, , 

. . 

mW9 A -w".ADI'~olan Davis Inc. FIGURE 3-15 bginee6ng and BOM~~UJVES. ~UR~NG SFOW & 

Environmental Management WU. .. mATIONAL AIRPORT 

Halifax, Nova ~cotia- . - I 
Station NDK4 

Regularmocirrg 

Station NOC-4 

Regular Monitorirrg , 

8--- -- 

A AD1 Nolan Davis Inc. Awg Engineering and 

Environmental Management Halifax, Nova Scotia 

Station NDK-4 

WMorwtoring 

Station NDK-6 

mmw 

Regular Wmitorirrg 
Comparison Report 

Runway Deicers 

Transport Canada 

Page 40 

Vegetative growth showed only 50 percent or less inhibition at bi-weekly application rates 

of 2400 mg/L or single applications of 20 glrn2* Such high levels would not normally occur, 

unless pure reagent was dumped directly on the ground during a spill. 

In summary, KA had little detectable impact on the surface water except for BOD and no 

detectable impact on groundwater, vegetation and other soil and stream life* It was superior 

to urea, in that it did not produce toxic levels of ammonia. For place such as HI, there 

may even be a slight benefit due to KA's alkalinity. 

Operationally KA was less satisfactory than urea. It worked better as an anti-icer than a deicer. Snow more readily stuck to the runway surface after KA application than after urea 

application Also, as it was a liquid, it needed a special sprayer. 

a. 

. . 

AD1 Nolan Da%s hc 214059-1561 
Comparison Report 

Runway De-icers 

Transport Canada 

4.0 CONCLUSIONS AND RECOMMENDATIONS 

4.1 Concl u sion s 

The results of three years of on-site evaluation at HIA indicate that KA, CMA and NaFo 

are more environmentally benign de-icen than urea. NaFo was very difticult to detect in 

the environment, indicating a rapid breakdown. Sodium levels were currently obscured by 

sodium input from other sources. It must be remembered that only 15 tons of NaFo were 

used in this experiment and normal operations would require around 200 tons of de-icers. 

If NaFo use is increased then sodium levels would have risen and may have had an impact. 

CMA was found at higher levels and both acetate and calcium and magnesium were easily 

detected. As HIA has an acid generation problem increased use of CMA would provide 

some buffering of this effect. At other airports the change in alkalinity and hardness may 

be less welcome. Potassium acetate was also more detectable than NaFo. In particular 

there was a significant increase in BOD, associated with the rise in acetate levels. However, 

there was no other discernable impact. 

CMA was difficult to apply and left a very sticky residue. NaFo was much easier to apply 

and did a much better, more rapid job than even urea. KA, being a liquid, was applied in 

a different manner which makes direct comparisons difficult. 

4.2 Recommendations 

From the results of the environmental studies, KA, CMA and NaFo can be used as de-icers 

and would give less environmental problems than urea. However, the initial operational 

problems noted during this evaluation would prompt the following recommendations: 

Urea, while operationally superior to all the de-ices assessed in this 

investigation, degrades to ammonia and creates an environmental impact. 

NaFo is recommended over CMA as it degraded more quickly and is 

opera tionally superior. 

a Transport Canada should approve NaFo as an alternative de-icer for w at 

Canadian airports, but should develop proper laboratory monitoring 

techniques. 

Transport Canada should tentatively approve KA, but implement a monituring 

program to establish the impact on the BOD5 created and the effect of the 

alkaline component. 

-- 

AD1 Nolan Davis Inc 214059-1%-1 
Comparison Report 

Runway De-iccrs 

 port Canada 

Page 42 

AD1 Nolan Davis would like to thank the staff at the Halifax International Airport, in 

particular Alyson MacDonald, Eloi Gaudet, and Dave Dawe, for the continuing cooperation 

through two winters of frustrating storm activity. Our gratitude goes to Dr. M. Silver, N. 

Collins for their solid technical input. 

The project manager would like to thank his colleagues at AD1 Nolan Davis who stayed out 

for hours in the vilest of maritime weather to collect samples and take readings and then 

returned to the office to work on preparing the report. 

Finally, we need to thank our sponsors, Transport Canada, Airports Group, and its 

representatives Alec Simpson, Lynn Warner and Victor Thorn. Their support was crucial 
Comparison Report 

Runway De-ices 

Transport Canada 

Page 43 

REFERENCES 

AD1 Nolan Davis Inc 1994. Environmental Impact from the Use of Potassium Acetate at 

Halifax International Airport. Report prepared for Transport Canada, Ottawa, Canada 

American Public Health Association. 1985. Standard Methods for Examination of Water 

and Wastewater, 16th Edition. 

Amrhein, C and J. Strong. 1990. The Effect Of Deicing Salts on Trace Metal Mobility In 

Roadside Soils. J. of Envirori. Qual. 19:765-772 

Beak Consultants Limited. 1988 Mitigation Measures to Control the Contamination of 

Stormwater with De-icer Fluids at Halifax International Airport. Prepared for Transport 

Canada, Rep. 2401.7 

Bowman, J. 1990k Acute Flow-Through Toxicity of Sodium Formate to Rainbow Trout. 

Study for Hachst Celenese by Analytical Biochemical Laboratories Inc 

Bowman, J. 1990B. Acute Row-Through Toxicity of Sodium Formate to Fathead Minnow. 

Study for Hoechst Celenese by Analytical Biochemical Laboratories Inc. 

Bretherick, L 1979. Handbook of Reactive Chemical Ham&. Second Edition 

Buttemorths, London. 

Burgess, D. 19%* Acute Flow-Through Toxicity of Sodium Formate to Daphnia mogna. 

Study for Hoechst Celenese by Analytical Biochemical Laboratories Inc 

Canadian British Consultants Limited 1978. hvir~~mental Clean-up Program Assessment 

Study, Halifax International Airport Prepared for the ~nvir~mental Protection Service and 

the Department of Fisheries and Environment, Halifax. 

Celmese Ific, 1991. Sodium Formate De-Ires ,. Technical Information Bulletin. 

Chevron Chemical Co. 1992. Chevron E36 Liquid Runway Deicer Technical Bulletins. 

- 

AD1 Nalan Davis Inc 21-9-Wl 
Comparison Report 

Runway De-iotn 

Trsaspon Canada 

Page 44 

Clayton, G. D. and F. E Clayton Wtors). 1991. Patty's Industrial Hygiene and 

Toxicology. Fourth Edition. John Wiley and Sons, New York. 

Clayton, G. D. and F. E Clayton (Editors). 1978. Patty's Industrial Hygiene and 

Toxicology. Third Revised Edition. John Wiley and Sons, New York. 

Comfort, G. 1993. Laboratory Tests of the De-Icing Performance of Potassium Acetate, ' 

Sodium Acetate and Urea. SWIFT Workshop, Vancouver, BC 

Daw, D. Personnel Communication. 

Dickerson, R. C J. Campbell and M. Stankard. 1955. Further Operating Experience on 

Biological Purification of Formaldehyde Wastes. Proceedings of the 9th Ind. Waste CodPurdue Univ. Ext. Ser. 87:33lW 351. 

Doetsdq R. No and To Me Cook. 1973. Introduction to Bacteria and their Ecobidogy. 

University Park Press, Baltimore. 

Doetxh, R.N. and Cook, TOM. 1973. Introduction to Bacteria and their Ecobiology. 

University Park Press, Baltimore. 

Elliott, HA, 1987. Effect of Calcium Magnesium Acetate of Highway Metal Mobility in Soil. 

Journal of Environmental Quality, Vol. 16, NO. 3, 1987. 

Environment Canada, 1985, Technical Information for Problem Spills - Urea, Technical 

Services Branch, Environmental Protection Service, Ottawa. 

Green, AL., and Smith, U. 1991. The replacement of ethylene glycol and propylene 

gIycoL kkheed Aeronautical Systems Company Georgia. 

Hart, B.T. 1974. A Compilation of Australian Water Quality Criteria. Caulfield Institute 

of Technology. Australian Water Resoufixs 'buncil, Techriical- paper, No. 7. Australian 

Government Publishing .--- Se"q, , CanNqa. . . I' . ..L I . ,. U'. c, , . #- 

, t .... . .4 1 .. . . - ,, . . . 

Hawker, L E and Linton, k H. 1971;. l%c~borganiSm& FunctioG Formaand Eiwironment. 

Elsevier, New York. . . , . , .. . , . .. , . , . .., 

AD1 Nolan Davis Inc - 2 1-0059-154-1 
Comparison Report 

Runway De-ices Page 45 

Transport Canada 

Hawker, LE and Linton, AH. 1971. Microorganisms: Function, Form and Environment, 

Elsevier, New York. 

Herlihy, L J., J. N. Gaalloway and A. L Mills. 1987. ~acterial utilization of Formic and 

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Hodgson, E R. B. Mailman and J. E Chambers. 1988. Dictionary of Toxicology. Van 

Norstrand Reinhold, New York. 

Hoechst Aktiengesellschaft. ' 1990. Prufung derakuten Toxizitat am KIeinkrebs Daphnia 

magna ubes 48 Stunden, Pharma Forschung Toxickologie und Pathologic, Frankfurt 

Germany. 

Homer, R.R 1988. Environmental Monitoring and Evaluation of Calcium Magnesium . 

acetate (CMA). National Cooperative Highway Research Program Report 305. 

Transportation Research Board, Washington, DC. 

Huntingdon Research Centre, 1991, Acute toxicity to Rainbow Trout, Reprot to BP 

Chemicals Limited, Hull. England on Clearway 1 de-icer. 

Hydro Qual. Inc. Biodegradation of Ice-B-Gon and its Effect on Receiving Water Dissokcd 

Oxygen, (for Chevron Chemical Co.). 

Institut fur gewerbliche Wasserwirtschaft und Luftrein haltung eV. 1990. Fschtest, akute 

Toxizitat, Koln, Germany. 

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Untersuchung des Produkes Landebahnent Safeway KA auf okologisches Verhalten nach 

Eintrag in ein terrestrisch - aquatisches System Koln, Germany. 

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for Deutsche Report for BP Chemie GmbH on Clearway 1 de-icer. 

Kato, Na Y. aBni and Yarnada. 1983. Microbial Utibtion of Methanol: Production of 

Useful Metabolites, in Advances in Biotechological Process, Alan R. liss , Inc New York, 

N.Y. 

AD1 Nolan Davis Inc . 21-0039-154-1 
Comparison Report 

Runway De-icers 

Transpon Canada 

Page 46 

Kirk-Othmer, "Encyclopedia of Chemical Technolo&, Third Edition, John Wiley & Sons, 

New York, New York, 1948 

Lumis, G, K Kha~a and K Carey. 1991. Sodium Formate as a De-icer: Plant 

Phytotoxicity and Metal Movement in Soil. Report prepared for Clelnese Canada Inc and 

Perstrop Polyols Inc Department of Horticultural Science, University of Gue!ph, Guelph. 

MacDougall, J.I. and Cann, DB, 1963. Soil Survey of Halifax County, Nova Scotia. Report 

No. 13, Nova Swtia Soil Survey, Truro, Nova Scotia. 

Mark, H. F, J. L McKetta, jr. and D. F. Othmer. 1966. Kirk-Othmer Encyclopedia of 

Chemical Technology. Second Edition. Volume 10. Interscience, New York 

Mazur, A, 1991. Evaluation of Sodium Formate - Winter 19904991. Safety and Technical 

Senices, Airports Group Transport Canada. 

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