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Priority Substances List - Statement of the Science Report for Ethylene Glycol
Appendix C: Management of Ethylene Glycol at Canadian Airports
Transport Canada has been the principal agency responsible for air transport in Canada and was responsible for initiating some monitoring of stormwater at international airports between 1970 and 1990. Monitoring during this period was infrequent, but, by 1990, all international airports in Canada had established stormwater monitoring programs (Transport Canada, 1995). Coinciding with the 1994 promulgation of a voluntary end-of-pipe discharge limit for glycol of 100 mg/L under CEPA, Transport Canada established a national program to sample and analyse airport effluent for glycols. Shortly thereafter, the Department of National Defence developed a similar program (Government of Canada, 1998).
At the present time in Canada, there are 726 certified airports, which range from large international airports to grass strips for landing small aircraft (Transport Canada, 1999a). The Canadian air transportation system is currently undergoing a major commercialization process initiated by the federal government. These changes could have an impact on future glycol management and monitoring. On July 13, 1994, the National Airports Policy (NAP) announced the transfer plans for 137 federally owned airports, including 26 airports under NAS, 71 regional/local airports, 31 small airports and 9 Arctic airports. Remote airports, which provide the only reliable year-round transportation link to isolated communities, will continue to be supported by the federal government (Transport Canada, 1999a). The 26 NAS airports (see Figure 5), which account for 94% of passenger and cargo traffic in Canada, include airports in provincial and territorial capitals, as well as any airport that handles at least 200 000 passengers per year (Transport Canada, 1999a). Under NAP, the federal government retains ownership of the 26 NAS airports and will lease them to Canadian Airport Authorities. These local operators are responsible for financial and operational management, while the federal government acts as landlord. For the regional and local airports, which serve scheduled passenger traffic, ownership is being offered to provincial and local governments, airport commissions, private businesses or other interests. Federal subsidies to these airports ceased March 31, 2000, unless exemptions were granted for special circumstances (Transport Canada, 1999a). The transfers of all NAS and other airports were to be completed by the end of fiscal year 1999/2000 (Transport Canada, 1999a).
Figure 5 Location of major airports under the National Airports Sytem (NAS) in Canada (Transport Canada, 199b)
As in the past, there will be no legislative requirement to continue GMPs and GOMPs. The plans provide a management control mechanism to ensure compliance with the CEPA guideline and the required actions to be taken when the guideline is not met. Exceedances of the guideline will be taken into account in the development of the plans for the following years (Simpson and Kent, 1999). ATAC plans to continue this exercise to maintain acceptable release levels of ethylene glycol and protect the local natural environment (Aalders, 1999). The plans identify the means of collecting, handling, storing, transporting and disposing of glycol-based fluids for each airport and also designate the areas in which deicing can take place and whether glycol recovery vehicles are required by the air carriers. Aircraft deicing is the air carriers' responsibility in terms of quantity, type and cost of containment, cleanup, storage and disposal. Airports and air carriers can manage glycols through a variety of ways, such as the use of vacuum trucks to collect the fluid on the apron, which can then be shipped off for recycling or treatment, and/or having underground piping and holding tanks to collect fluid immediately below the planes. Collected fluid may be diverted to sanitary sewer systems, storm sewer systems or tanker truck fill stations (MCIAA, 1997).
Transport Canada determines which airports require GMPs and which require GOMPs. Each identified airport must have a plan, which then must be approved by the airport general manager. Transport Canada will require a deicing/anti-icing licence if the plan requirements are not met (Transport Canada, 1999c). The GMPs and GOMPs are updated on an annual basis and, together with the regular monitoring of stormwater effluent during the deicing season, are designed with the objective that all airports currently operated by Transport Canada are compliant with the CEPA guidelines (Transport Canada, 1997c). The 26 NAS airports will remain on federal lands and therefore will still be subject to the CEPA Part IV glycol discharge guideline and the requirements under the Fisheries Act. Under CEPA Part IV, a total glycol discharge limit of 100 mg/L prior to release into receiving waters has been established for the protection of the environment and is used when designing and implementing the management of aircraft anti-icing and deicing activities (Canada Gazette, 1994). In addition, the Canadian water quality guideline for ethylene glycol has been prepared by the Task Force on Water Quality Guidelines for the CCME and set at a level of 192 mg/L for the protection of freshwater aquatic life. A related 5-day BOD effluent quality and wastewater treatment guideline was set at 20 mg/L for stormwater samples at federal establishments in 1976 (Environment Canada, 1976a). The above guidelines are not regulated values; however, the effects of ethylene glycol release can be measured against Sections 35 and 36 of the Fisheries Act, which deal with the destruction of fish passageways, alteration of fish habitat and deposition of substances deleterious to fish. Violations of these sections of the Act can result in penalties and fines when enforced.
Although most airports report releases of "total glycol," by far the vast majority of glycol used in Canada for aircraft anti-icing/deicing is ethylene glycol (Leroux, 1999). Propylene glycol, the other glycol used for this purpose in Canada, is reported to be used only minimally at Hamilton Airport, Moncton Airport, Vancouver International Airport and Winnipeg International Airport and by Federal Express air carriers (MacCallum, 1998; Moncton Airport, 1999; Thaler, 1999).
Table 3. Concentrations of ethylene glycol sampled at selected monitoring stations of Canadian airports for the 1997/98 and 1998/99 deicing seasons
Table 5. Concentration of ethylene glycol in groundwater sampled at Canadian airports
Table 6. Deterministic estimates of upper-bounding daily intakes for adults by dermal absorption from consumer products
Effluent concentration (mg/L) |
Descriptor |
EEV in receiving water (mg/L) |
Quotient1 |
|---|---|---|---|
4700 |
highest maximum - 1997-1999 seasons (Table 4) |
470 |
0.72 |
1076 |
95th percentile - spring maxima 1997-1999 (Table 7) |
108 |
0.17 |
200 |
99th percentile - all data, 1997-1999 (Table 4) |
20 |
0.03 |
100 |
CEPA Part IV guideline |
10 |
0.02 |
Effluent concentration (mg/L) |
Descriptor |
EEV in receiving water (mg/L) |
Quotient1 |
|---|---|---|---|
4700 |
highest maximum - 1997-1999 seasons (Table 4) |
470 |
0.99 |
1076 |
95th percentile - spring maxima 1997-1999 (Table 7) |
108 |
0.23 |
200 |
99th percentile - all data, 1997-1999 (Table 4) |
20 |
0.04 |
100 |
CEPA Part IV guideline |
10 |
0.02 |
Effluent concentration (mg/L) |
Descriptor |
EEV in receiving water (mg/L) |
Oxygen deficit1 (mg/L) |
Quotient2 |
|---|---|---|---|---|
4700 |
highest maximum - 1997-1999 seasons (Table 4) |
470 |
57.9 |
16.1 |
1076 |
95th percentile - spring maxima 1997-1999 (Table 7) |
108 |
13.8 |
3.8 |
200 |
99th percentile - all data, 1997-1999 (Table 4) |
20 |
3.1 |
0.86 |
100 |
CEPA Part IV guideline |
10 |
1.9 |
0.53 |
1 Oxygen deficit is the application of the Streeter and Phelps (1925) oxygen sag model to provide the number of mg O2/L below the saturation point of 13.1 mg O2/L and resulting from the assumed EEV in the receiving water.
2The quotient represents the ratio between the calculated oxygen deficit and the minimal oxygen deficit of 3.6 mg/L needed to meet the cold-water CCME freshwater guideline of 9.5 mg/L, assuming a water temperature of 4°C.
Route of exposure |
Intakes of ethylene glycol for various age groups in the exposed population (mg/kg-bw per day) |
|||||
|---|---|---|---|---|---|---|
0-6 months1 |
7 months - 4 years 2 |
5-11 years 3 |
12-19 years4 |
20-59 years5 |
60+ years6 |
|
Inhalation7 |
28 |
60 |
47 |
27 |
23 |
20 |
Ingestion of soil8 |
17 |
28 |
9 |
2 |
2 |
2 |
Total daily intake |
45 |
88 |
56 |
29 |
25 |
22 |
1 Assumed to weigh 7.5 kg, to breathe 2.1 m3 of air per day and to ingest 30 mg of soil per day (EHD, 1998).
2 Assumed to weigh 15.5 kg, to breathe 9.3 m3 of air per day and to ingest 100 mg of soil per day (EHD, 1998).
3 Assumed to weigh 31.0 kg, to breathe 14.5 m3 of air per day and to ingest 65 mg of soil per day (EHD, 1998).
4Assumed to weigh 59.4 kg, to breathe 15.8 m3 of air per day and to ingest 3 0 mg o f soil per day (EHD, 1998).
5Assumed to weigh 70.9 kg, to breathe 16.2 m3 of air per day and to ingest 30 mg of soil per day (EHD, 1998).
6Assumed to weigh 72.0 kg, to breathe 14.3 m3 of air per day and to ingest 30 mg of soil per day.(EHD, 1998).
7Based on the maximum daily average concentration (100 mg/m3) predicted in ambient air at ground level at a distance of 1.8 km from the facility perimeter of an industrial point source of discharge to the atmosphere (Environment Canada, 1997b). The same concentration is assumed for indoor air.
8 Based on the maximum reported concentration (4290 mg/kg) in soil near an industrial point source of discharge (AEP, 1996).
Food item |
Intakes of ethylene glycol for various age groups in the general population (µg/kg-bw per day) |
|||||
|---|---|---|---|---|---|---|
0-6 months1 |
7 months - 4 years2 |
5-11 years3 |
12-19 years4 |
20-59 years5 |
60+ years6 |
|
Cake7 |
0.3 |
19.4 |
27.8 |
23.6 |
10.7 |
7.9 |
Pie, other8 |
1.0 |
2.4 |
3.3 |
1.8 |
1.7 |
1.6 |
Candy, other9 |
1.1 |
11.8 |
9.2 |
5.9 |
2.5 |
1.7 |
Soft drinks10 |
<0.1 |
0.7 |
0.6 |
0.4 |
0.2 |
0.1 |
Wine11 |
- |
<0.1 |
0.1 |
0.2 |
1.6 |
1.0 |
Total daily intake12 |
<2.5 |
<34.4 |
41.0 |
31.9 |
16.7 |
12.3 |
1 Assumed to weigh 7.5 kg and to consume food items at average daily rates indicated in EHD (1998).
2 Assumed to weigh 15.5 kg and to consume food items at average daily rates indicated in EHD (1998).
3 Assumed to weigh 31.0 kg and to consume food items at average daily rates indicated in EHD (1998).
4 Assumed to weigh 59.4 kg and to consume food items at average daily rates indicated in EHD (1998).
5 Assumed to weigh 70.9 kg and to consume food items at average daily rates indicated in EHD (1998).
6 Assumed to weigh 72.0 kg and to consume food items at average daily rates indicated in EHD (1998).
7 Assumed to contain ethylene glycol due to contact with RCF. Based on a maximum reported concentration of 34 mg/kg in fruit cake in the U.K. (Castle et al., 1988).
8 Assumed to contain ethylene glycol due to contact with RCF. Based on the limit of detection (10 mg/kg) for analysis of meat pies in the U.K. (Castle et al., 1988).
9 Assumed to contain ethylene glycol due to contact with RCF. Based on a maximum reported concentration of 34 mg/kg in boiled sweets in the U.K. (Castle et al., 1988).
10 Assumed to contain ethylene glycol due to migration from PETE bottles. Based on a maximum reported concentration of 0.104 mg/L in 3% acetic acid (used to simulate carbonated beverages) following storage for 6 months at 32°C (Kashtock and Breder, 1980).
11 Based on the maximum reported concentration (6.25 mg/L) of ethylene glycol in wine in Italy (Gaetano and Matta, 1987).
12 It is assumed that there are no daily intakes of ethylene glycol from the remaining 176 food items for which daily rates of consumption are available in EHD (1988), since no data are available concerning concentrations of ethylene glycol in these food items.
|
Dose of ethylene glycol (mg/kg-bw per day) |
||||
|---|---|---|---|---|---|
0 (A) |
0 (B) |
40 |
200 |
1000 |
|
Incidence of calcium oxalate crystalluria in male rats |
|||||
Incidence at 6-month interim sacrifice (Snellings, 2000) |
0/10 |
0/10 |
0/10 |
0/10 |
6/10 |
Incidence at 12-month interim sacrifice (Snellings, 2000) |
0/10 |
0/10 |
0/10 |
0/10 |
10/10 |
Overall incidence reported in DePass et al. (1986a) |
0/128 |
0/128 |
0/129 |
0/129 |
16/116 (p < 0.001) |
Incidence of tubular hyperplasia in male rats |
|||||
Incidence at 6-month interim sacrifice (Snellings, 2000) |
1/10 |
3/10 |
2/10 |
2/10 |
10/10 |
Incidence at 12-month interim sacrifice (Snellings, 2000) |
9/10 |
8/10 |
8/10 |
8/10 |
0/10 |
Overall incidence reported in DePass et al. (1986a) |
10/128 |
11/128 |
10/129 |
10/129 |
10/116 |
Incidence of tubular dilation in male rats |
|||||
Incidence at 6-month interim sacrifice (Snellings, 2000) |
0/10 |
0/10 |
0/10 |
1/10 |
10/10 |
Overall incidence reported in DePass et al. (1986a) |
0/128 |
0/128 |
0/129 |
1/129 |
10/116 (p < 0.001) |
Incidence of peritubular nephritis in male rats |
|||||
Incidence at 6-month interim sacrifice (Snellings, 2000) |
0/10 |
0/10 |
0/10 |
0/10 |
6/10 |
Incidence at 12-month interim sacrifice (Snellings, 2000) |
2/10 |
4/10 |
4/10 |
7/10 |
0/10 |
Overall incidence reported in DePass et al. (1986a) |
2/128 |
4/128 |
4/129 |
7/129 |
6/116 |
Incidence of oxalate nephrosis in male rats |
|||||
Incidence in animals dead or sacrificed when moribund (Snellings, 2000) |
0/19 |
0/18 |
0/19 |
0/16 |
95/96 |
Overall incidence reported in DePass et al. (1986a) |
0/128 |
0/128 |
0/129 |
0/129 |
95/116 (p < 0.001) |
Incidence of hydronephrosis in male rats |
|||||
Incidence (unilateral) at 6-month interim sacrifice (Snellings, 2000) |
0/10 |
0/10 |
0/10 |
0/10 |
1/10 |
Incidence at 24-month sacrifice (Snellings, 2000) |
1/69 |
1/70 |
0/70 |
0/17 |
no data |
Incidence in animals dead or sacrificed when moribund (Snellings, 2000) |
0/19 |
3/18 |
0/19 |
3/16 |
71/96 |
Overall incidence reported in DePass et al. (1986a) |
1/128 |
4/128 |
0/129 |
3/129 |
72/116 (p < 0.001) |
Incidence of glomerulonephrosis in male rats |
|||||
Incidence at 18-month sacrifice (Snellings, 2000) |
20/20 |
19/20 |
20/20 |
20/20 |
no data |
Incidence at 24-month sacrifice (Snellings, 2000) |
69/69 |
70/70 |
70/70 |
73/73 |
no data |
Incidence in animals dead or sacrificed when moribund (Snellings, 2000) |
17/19 |
17/18 |
13/19 |
14/16 |
5/96 |
Overall incidence reported in DePass et al. (1986a) |
106/128 |
106/128 |
103/129 |
107/129 |
5/116 |
1 The incidence of ethylene-glycol induced renal lesions has been verified from the pathology reports on individual animals (Brantom, 2000b).
Renal histopathology |
BMD05 (mg/kg-bw per day) |
95% LCL on BMD05 (mg/kg-bw per day) |
p-value |
Chi-square |
df |
Degree |
|---|---|---|---|---|---|---|
Incidence of individual nephrons with degenerative changes: 0/15, 1/15, 1/15, 2/15 and 5/15 (p < 0.05) |
83.8 |
45.1 |
0.86 |
0.74 |
3 |
4 |
Incidence of individual nephrons with degenerative changes and occasional oxalate crystal: 0/15, 0/15, 0/15, 1/15 and 4/15 (p < 0.05) |
217.6 |
75.4 |
0.75 |
0.59 |
2 |
4 |
Incidence of several nephrons with degenerative changes and frequent crystals: 0/15, 0/15, 0/15, 0/15 and 2/15 |
553.9 |
180.1 |
0.99 |
0 |
3 |
4 |
Incidence of generalized tubular damage and heavy crystals: 0/15, 0/15, 0/15, 0/15 and 4/15 (p< 0.05) |
465.5 |
158.1 |
0.99 |
0.02 |
3 |
4 |
Total animals with tubular damage: 0/15, 1/15, 1/15, 4/15 (p < 0.05) and 15/15 (p < 0.01) |
48.6 |
21.5 |
0.62 |
0.94 |
2 |
4 |
1 Male Wistar rats were administered ethylene glycol in the diet for 16 weeks at doses of 0, 35, 71, 180 or 715 mg/kg-bw per day (Gaunt et al., 1974).
Renal histopathology |
BMD05 (mg/kg-bw per day) |
95% LCL on BMD05 (mg/kg-bw per day) |
p-value |
Chi-square |
df |
Degree |
|---|---|---|---|---|---|---|
Incidence of tubular dilation: 0/10, 0/10, 0/10, 5/10 and 8/9 |
316.4 |
85.5 |
0.12 |
4.25 |
2 |
4 |
Incidence of tubular degeneration: 0/10, 0/10, 0/10, 5/10 and 9/9 |
501.9 |
214.9 |
0.96 |
0.26 |
3 |
4 |
Incidence of intratubular crystals: 0/10, 0/10, 0/10, 3/10 and 8/9 |
453.7 |
145 |
0.75 |
1.2 |
3 |
4 |
