International Air Quality Advisory Board 1997-1999 Priorities Report

INTERNATIONAL AIR QUALITY ADVISORY BOARD
1997-1999 PRIORITIES REPORT

LINKING CANADA AND UNITED STATES SOURCES AND SOURCE REGIONS OF SELECTED PERSISTENT TOXIC SUBSTANCES TO DEPOSITION IN THE GREAT LAKES BASIN: A PROGRESS REPORT

INTERNATIONAL AIR QUALITY ADVISORY BOARD
JULY 1999

4.1 INTRODUCTION

In 1985, the Great Lakes Water Quality Board of the International Joint Commission (IJC) designated eleven critical pollutants in the Great Lakes basin. It did so in the knowledge that there were several significant pathways for these contaminants to reach the lakes, including atmospheric transport and deposition. The governments of the United States and Canada created Annex 15 (Airborne Toxic Substances) of the Great Lakes Water Quality Agreement to provide for further research and control of this contaminant pathway.

Further, in 1997, the governments of the United States and Canada jointly developed the Great Lakes Binational Toxics Strategy (BTS) (Canada and United States, 1997) with commitments to quantified reductions in the amount of contaminants released into the environment. The complete listing of Level I and Level II persistent, bioaccumulative substances designated under the strategy is shown in Table 1. Level I contaminants are largely those designated as critical pollutants by the Water Quality Board in 1985.

Table 1. Persistent Toxic Substances (Level I and Level II) Identified in the Great Lakes Binational Toxics Strategy
Critical pollutants identified by WQB in 1985 are indicated with an asterisk (*).
Persistent organic pollutants from CEC Council Resolution #95-5 are identified with a caret (^).
LEVEL I LEVEL II

Aldrin ^
Dieldrin *^
Benzo(a)Pyrene {B(a)P} *
Chlordane ^
DDT, DDD, DDE *^
Alkylated lead *
Mercury * and its compounds
Mirex *^
Octachlorostyrene
PCBs *^
Dioxins (PCDD; 2,3,7,8-TCDD) *^
Furans (PCDF; 2,3,7,8-TCDF) *^
Toxaphene *^
NOTE: Hexabromobiphenyl and Penta-chlorophenol are listed as POPs on the CEC Council Resolution #95-5 but are not included on the Strategy list.

Cadmium and its compounds
1,4-Dichlorobenzene
3,3'-Dichlorobenzidine
Dinitropyrene
Endrin^
Heptachlor and heptachlor epoxide
Hexachlorobutadiene (1,2- and 1,3-)
Hexachlorocyclohexane (including alpha, beta, delta, lindane)
4,4'-Methylenebis (2-chloroaniline)
Pentachlorobenzene
Pentachlorophenol
Tetrachlorobenzene (1,2,3,4- and 1,2,4,5-)
Tributyl tin
Polycyclic aromatic hydrocarbons (PAHs)^ as a group, including but not limited to:
-Anthracene -Perylene
-Benzo(a)anthracene -Phenanthrene
-Benzo(g,h,i)perylene

Pollutants can enter a given lake through a variety of pathways, including atmospheric deposition, direct discharge or surface-runoff into the lake or its tributaries, and resuspension of contaminated sediments. Depending on the nature of the pollutant and the location and character of its sources, the relative contribution of each pathway will be different for each pollutant for a given lake. Unfortunately, for many pollutants of concern in the Great Lakes, there is insufficient information to make mass balance estimates. However, in a few instances, sufficient measurements have been made to make estimates of the relative importance of different loading pathways. While the estimates shown in Table 2 are very uncertain, it appears that the atmospheric deposition pathway is predominant for some pollutants for some lakes. For example, atmospheric deposition appears to be the dominant loading pathway for Lake Superior (for the pollutants for which estimates could be found, i.e., Table 2).

Table 2. Percent of Great Lakes Loadings Attributable to the Atmospheric Deposition Pathway^l
Pollutant Lake Superior Lake Michigan Lake Huron Lake Erie Lake Ontario
DDT 97^a 98^a 97^a 22^a 31^a
Lead 97^a; 64^b; 69^d 99^a 98^a 46^a 73^a
Mercury 73^d > 80^j ^k ^k ^k
PCB's 90^a; ~ 95^b,c; 82^d 58^a 78^a 13^a 7^a
PCDD/F ~100^e; ~80^f 50-100^e (PCDD);
5-35^e (PCDF);
88^f 86^f ~40^f 5-35 (PCDD)^e;
< 5 (PCDF)^e
Benzo(a)pyrene 96^a 86^a 80^a 79^a 72^a
Hexachloro-benzene 99^f 95^f 96^f > 17^f 40^f
Atrazine 97^h ~30^g; 23^h ~20^h ~10-20^h ~5^h
Mirex ^k ^k ^k ^k ~5^a
References and Notes
(a) Strachan and Eisenreich (1988), percentages of total inputs; (b) Hoff et al. (1996); (c) Net loss of PCB's to the atmosphere of 1600 kg/year; total non-atmospheric inputs of approximately 70 kg/year; (d) Dolan et al. (1993); (e) Pearson et al. (1998); (f) Cohen et al. (1995); (g) Rygwekski et al. (1999); (h) Schottler and Eisenreich (1997); (j) Mason and Sullivan (1997); (k) no estimates could be found; (l) there are significant uncertainties in most, if not all, of the estimates in this table.

For persistent toxic substances for which atmospheric deposition may be a significant loading source to the lakes, it is critical to determine:

the amount of such deposition to the lakes;
the relative importance of contributions from local, regional, national, continental, and global source regions; and
the relative importance of different source categories.

These elements are necessary to develop strategic and defensible programs and policies for reducing loadings and associated toxicological effects.

Table 1. Persistent Toxic Substances (Level I and Level II) Identified in the Great Lakes Binational Toxics Strategy Critical pollutants identified by WQB in 1985 are indicated with an asterisk (*). Persistent organic pollutants from CEC Council Resolution #95-5 are identified with a caret (^).
LEVEL I	LEVEL II
Aldrin ^ Dieldrin ^ Benzo(a)Pyrene {B(a)P} Chlordane ^ DDT, DDD, DDE ^ Alkylated lead Mercury * and its compounds Mirex ^ Octachlorostyrene PCBs ^ Dioxins (PCDD; 2,3,7,8-TCDD) ^ Furans (PCDF; 2,3,7,8-TCDF) ^ Toxaphene ^ NOTE: Hexabromobiphenyl and Penta-chlorophenol are listed as POPs on the CEC Council Resolution #95-5 but are not included on the Strategy list.*	Cadmium and its compounds 1,4-Dichlorobenzene 3,3'-Dichlorobenzidine Dinitropyrene Endrin^ Heptachlor and heptachlor epoxide Hexachlorobutadiene (1,2- and 1,3-) Hexachlorocyclohexane (including alpha, beta, delta, lindane) 4,4'-Methylenebis (2-chloroaniline) Pentachlorobenzene Pentachlorophenol Tetrachlorobenzene (1,2,3,4- and 1,2,4,5-) Tributyl tin Polycyclic aromatic hydrocarbons (PAHs)^ as a group, including but not limited to: -Anthracene -Perylene -Benzo(a)anthracene -Phenanthrene -Benzo(g,h,i)perylene

Table 2. Percent of Great Lakes Loadings Attributable to the Atmospheric Deposition Pathway^l
Pollutant	Lake Superior	Lake Michigan	Lake Huron	Lake Erie	Lake Ontario
DDT	97^a	98^a	97^a	22^a	31^a
Lead	97^a; 64^b; 69^d	99^a	98^a	46^a	73^a
Mercury	73^d	> 80^j	^k	^k	^k
PCB's	90^a; ~ 95^b,c; 82^d	58^a	78^a	13^a	7^a
PCDD/F	~100^e; ~80^f	50-100^e (PCDD); 5-35^e (PCDF); 88^f	86^f	~40^f	5-35 (PCDD)^e; < 5 (PCDF)^e
Benzo(a)pyrene	96^a	86^a	80^a	79^a	72^a
Hexachloro-benzene	99^f	95^f	96^f	> 17^f	40^f
Atrazine	97^h	~30^g; 23^h	~20^h	~10-20^h	~5^h
Mirex	^k	^k	^k	^k	~5^a
References and Notes (a) Strachan and Eisenreich (1988), percentages of total inputs; (b) Hoff et al. (1996); (c) Net loss of PCB's to the atmosphere of 1600 kg/year; total non-atmospheric inputs of approximately 70 kg/year; (d) Dolan et al. (1993); (e) Pearson et al. (1998); (f) Cohen et al. (1995); (g) Rygwekski et al. (1999); (h) Schottler and Eisenreich (1997); (j) Mason and Sullivan (1997); (k) no estimates could be found; (l) there are significant uncertainties in most, if not all, of the estimates in this table.

INTERNATIONAL AIR QUALITY ADVISORY BOARD 1997-1999 PRIORITIES REPORT

INTERNATIONAL AIR QUALITY ADVISORY BOARD
1997-1999 PRIORITIES REPORT