- Email: [email protected]
Contaminant Exposure in Montrealers of Asian Origin Fishing the St. Lawrence River: Exploratory Assessment
Environmental Research Section A 80, S159—S165 (1999) Article ID enrs.1998.3911, available online at http://www.idealibrary.com on
Contaminant Exposure in Montrealers of Asian Origin Fishing the St. Lawrence River: Exploratory Assessment1 Tom Kosatsky,* - Raymond Przybysz,* Bryna Shatenstein,* Jean-Philippe Weber,- and Ben Armstrong‡ *Occupational and Environmental Health, Montreal Public Health Program, 1301 Sherbrooke East, Montreal, Quebec H2L 1M3, Canada, and Department of Occupational Health, McGill University, Montreal, Quebec, Canada; -Quebec Toxicology Center, Montreal, Quebec, Canada; and ‡London School of Hygiene, London, England Received December 22, 1997
and recency of arrival in Canada was found for the Bangladeshis. These data suggest a distinct pattern of tissue organochlorines, which we postulate relates to exposure prior to arrival in Canada and perhaps to the ongoing consumption of foods (other than St. Lawrence River sportfish) specific to these groups. 1999 Academic Press Key Words: Asians; DDT; PCB; sportfish; St. Lawrence.
Fishing and fish consumption are widely practiced among members of certain ethnocultural groups. Informal assessment led us to ascribe high levels of consumption of locally caught sportfish to Montrealers of Asian origin and to hypothesize that their choices of species and fish organs differ from those of the majority group. An exploratory assessment of contaminant bioindicators reflective of St. Lawrence River fish consumption was conducted in late 1995 among nine Vietnamese and nine Bangladeshi Montreal sportfishers identified by community contacts. Vietnamese participants, six men and three women, were 27—70 (median 36) years of age and had immigrated to Canada 3—20 (median 7) years earlier. In contrast, the nine Bangladeshi males aged 28–41 (median 34) years had been in Canada for 2–13 (median 4) years. Bioindicator concentrations among Bangladeshi and Vietnamese participants are compared to those found for majority-community Montreal-area highlevel consumers recruited on the St. Lawrence River during winter 1995. All results are presented as the median and 90th percentile. Hair mercury concentrations were higher for both Vietnamese (1.2, 4.6 lg/g) and Bangladeshis (1.1, 2.3 lg/g) than for majority-community sportfishers (0.7, 1.9 lg/g). Certain organochlorine levels, specifically total PCB (estimated by plasma Aroclor 1260), p,p -DDT, p,p -DDE, and B-BHC, were highest in the Bangladeshis compared to Vietnamese and to majority-community sportfishers. In contrast, plasma levels of other pesticides were low in all three groups, including mirex, chlordane, and cis-nonachlor. A correlation between plasma p,p -DDT levels
INTRODUCTION
An exploratory study of patterns of fish consumption and exposure to chemical substances potentially derived from fish was conducted in the fall of 1995 among adult Asian-origin sportfishers resident in the Montreal region. Preliminary assessment by our group had suggested that fishing practices and fish consumption patterns among Asian communities in Montreal might convey risk of excessive exposure to St. Lawrence River contaminants. Specifically, we wondered if frequent sportfish consumption, preference for bottom-feeding species such as carp and eel, and consumption of organ meats might occur. Participant recruitment and community and individuallevel nutritional assessment are described in a companion paper by Shatenstein et al. (1998). Here, we present tissue concentrations of mercury, arsenic, and certain organochlorine compounds in a pilot study of Vietnamese and Bangladeshi sportfishers living in Montreal and fishing the St. Lawrence River. METHODS
This study was funded by the Health Component of the St. Lawrence Action Plan-Vision 2000, Health Canada, Main Building, Room 0301 A1, Tunney’s Pasture, Ottawa, Ontario, K1A 0K9. The study protocol was approved by the Clinical Research Ethics Committee of Maisonneuve-Rosemont Hospital, Montreal.
Preliminary discussions with representatives of several Asian communities living in Montreal indicated that the city’s Vietnamese and Bangladeshi S159 0013-9351/99 $30.00 Copyright 1999 by Academic Press All rights of reproduction in any form reserved.
S160
KOSATSKY ET AL.
communities include many individuals who fish the nearby St. Lawrence River and might participate in an assessment of their sportfishing practices and of their exposure to contaminants derived from sportfish. Contact with community groups and personal recruitment by study resource persons who were members of Montreal’s Vietnamese and Bangladeshi communities led to the enrollment of nine Vietnamese (three of whom were women) and nine Bangladeshi (all men) sportfishers. Samples of blood and hair were collected during October—December 1995. Blood collection followed an overnight fast. Total mercury was analyzed for the most proximal hair centimeter by cold vapor atomic absorption spectrometry (Pharmacia Model 120). Inorganic arsenic was extracted from urine following complexation with potassium iodide; predigestion with sodium persulfate converted total to inorganic arsenic. Total urinary and inorganic arsenic were analyzed by graphite furnace atomic absorption spectrometry (Perkin Elmer Model 5100); both measurements were corrected for creatinine. Plasma was analyzed for 14 PCB congeners and for organochlorine pesticides using gas chromatography with electron capture. Organochlorine analyses have been corrected for total plasma lipid levels, as described by Brown and Lawton (1984). An Aroclor 1260 index was calculated as five times the sum of congeners 138 and 153. All measurements below the limit of detection (LOD) were replaced by the value of LOD/(2 (Hornung and Reed, 1990). The lowest, highest, median, and 90th percentile values are presented for each contaminant measured. A standardized comparison of PCB congener and pesticide results is presented by comparing ratios of the 25th, 50th, and 75th percentile concentrations for each contaminant as measured in the Vietnamese and Bangladeshis to the 50th percentile concentration as measured in a group of 25 high-level Montreal-area ice-fishers who are themselves described separately in this issue (Kosatsky et al., 1998). Linear regressions relate selected plasma organochlorine concentrations to participants’ age and to years of residency in Canada.
FIG. 1. Total hair mercury (cm 0—1) measured for Bangladeshi, Vietnamese, and majority-community St. Lawrence River sportfishers.
area sportfish consumers recruited during winter 1995 (0.73, 1.88 lg/g) (Fig. 1). Inorganic and total urinary arsenic concentrations (creatinine adjusted) were higher for Bangladeshi (medians 26.7 and 54.8 lg/g) than for Vietnamese fishers (medians 14.0 and 39.7 lg/g) (Fig. 2).
RESULTS
Sociodemographic characteristics as well as attributes of fish consumption are presented separately for the nine Vietnamese and nine Bangladeshi participants (Shatenstein et al., 1998). Hair mercury concentrations were somewhat higher among Vietnamese (median 1.23 lg/g, 90th percentile 4.62 lg/g) than among Bangladeshi participants (1.07, 2.29 lg/g) or high-level Montreal-
FIG. 2. Urinary arsenic (creatinine adjusted) measured for Bangladeshi and Vietnamese residents of Montreal fishing the St. Lawrence River.
S161
CONTAMINANT EXPOSURE IN ASIAN FISHERS IN MONTREAL
1.16 lg/g for the Bangladeshi participants and 0.59 lg/g for the Vietnamese compared to 0.77 lg/g for the local high-level sportfish consumers. No Bangladeshi or Vietnamese participant was found to have an Aroclor 1260 index greater than the Health Canada recommended limit of 5 lg/L for women of reproductive age or 20 lg/L for the general population (not adjusted for total plasma lipids) (Health Protection Branch, 1986). Comparison of standardized ratios of specific PCB congeners suggests that the Bangladeshis show particular elevations for lower-numbered congeners (Fig. 3). Years of residence in Canada correlated with their plasma Aroclor 1260 index for the nine Bangladeshi participants (r2"0.64, influenced largely by one extreme data point) but not for the Vietnamese (Fig. 4).
Inorganic arsenic alone was measured in 25 highlevel Montreal-area fishers; urinary arsenic was detected in a single member of this group. Detectable concentrations were found for all 14 PCB congeners among at least some Bangladeshi participants and (except for congener 128) among at east some Vietnamese. For congener 128, fewer than 2/3 Bangladeshis had detectable plasma concentrations, as was the case for congeners 52, 101, and 105 among the Vietnamese (Table 1). Median concentrations for all congeners were higher among the Bangladeshi participants than among the Vietnamese. Further, among the Bangladeshi, concentrations of all congeners were as high as or higher than those measured in local majority-community high-level sportfish consumers. Median Aroclor 1260 concentrations (total plasma lipid adjusted) were
TABLE 1 Plasma PCB Congener Concentrations (Total Plasma Lipid Adjusted) in 9 Bangladeshi, 9 Vietnamese, and 25 High-Level Majorty-Community Sportfish Consumers Aroclor 1260
PCB congener
Nonadj. Adjusted 28
52
99
101
105
118
128
138
153
156
170
180
183
187
Unit of measurement Laboratory detection limit? Recommended tolerable limit@
lg/L 0.2 5/20
&&&&&&&&&&&&&& lg/g total plasma lipids &&&&&&&&&&&&&&&& &&&&&&&&&&&&&&&&&&& 0.02 &&&&&&&&&&&&&&&&&&&& &&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&&&
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 9 1.80 7.82 14.7 19.4
Number'tolerable limit@
0/0
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 9 1.17 4.41 6.61 9.75
Number'tolerable limit@
0/0
&&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&&
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
25 25 2.61 5.31 7.61 94.5
25 25 0.32 0.77 1.50 8.67
Number'tolerable limit@
1/1
&&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&&
&&&&&&&&& Bangladeshi &&&&&&&&&&&&&&&&&&&&&&&&&&& 9 9 0.33 1.16 1.89 3.51
9 9 0.01 0.01 0.02 0.03
9 9 0.00 0.01 0.02 0.04
9 9 0.01 0.03 0.05 0.06
9 9 0.00 0.02 0.03 0.03
9 8 0.00 0.02 0.03 0.03
9 9 0.01 0.06 0.09 0.14
9 3 0.00 0.00 0.00 0.01
9 9 0.03 0.10 0.16 0.29
9 9 0.04 0.12 0.20 0.38
9 8 0.00 0.01 0.02 0.05
9 9 0.01 0.03 0.06 0.11
9 9 0.02 0.07 0.13 0.27
9 8 0.00 0.02 0.03 0.04
9 9 0.01 0.04 0.09 0.17
&&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&& Vietnamese 9 9 0.21 0.59 0.82 1.14
9 6 0.00 0.00 0.01 0.04
9 3 0.00 0.00 0.01 0.01
9 9 0.00 0.01 0.01 0.02
9 5 0.00 0.00 0.00 0.00
9 5 0.00 0.00 0.01 0.01
9 9 0.00 0.02 0.03 0.04
9 0 0.00 0.00 0.00 0.00
9 9 0.02 0.05 0.07 0.09
9 9 0.02 0.07 0.09 0.13
9 8 0.00 0.01 0.02 0.02
9 9 0.01 0.02 0.03 0.04
9 9 0.02 0.04 0.08 0.11
9 7 0.00 0.01 0.01 0.02
9 9 0.01 0.02 0.04 0.06
High-level local consumers 25 8 0.00 0.00 0.01 0.17
25 2 0.00 0.00 0.00 0.02
25 25 0.01 0.02 0.04 0.33
25 8 0.00 0.00 0.01 0.01
25 17 0.00 0.01 0.02 0.12
25 24 0.00 0.03 0.11 0.43
25 2 0.00 0.00 0.01 0.01
25 25 0.02 0.07 0.12 0.78
25 25 0.04 0.08 0.17 0.89
25 25 0.01 0.01 0.03 0.13
25 25 0.01 0.02 0.06 0.19
25 25 0.02 0.06 0.18 0.51
25 13 0.00 0.00 0.02 0.08
25 25 0.01 0.02 0.07 0.32
?Based on nonadjusted measurements (lg/L). @Health Canada’s Aroclor 1260 recommended tolerable limit (based on nonadjusted measurements): 5 lg/L for women of reproductive age/20 lg/L for the general population.
S162
KOSATSKY ET AL.
FIG. 3. Selected PCB congeners (total plasma lipid adjusted) among Bangladeshi, Vietnamese, and majority-community St. Lawrence River sportfishers classed as High-level consumers.
Among the organochlorine pesticides analyzed, two (a- and c-chlordane) were detected in none of the participants, while aldrin was detected in only one (Table 2). Levels of plasma p,p -DDT, p,p -DDE, and b-benzene hexachloride (b-BHC) were markedly higher in Bangladeshi and in Vietnamese participants than in majority-community ice-fishers (Kosatsky et al., 1998). Specific comparisons include
median p,p -DDT concentrations of 0.34 lg/g among the Bangladeshi, 0.16 lg/g among the Vietnamese, and 0.01 lg/g among the high-level majority-community sportfish consumers. For p,p -DDE, (a more stable breakdown product of p,p -DDT), the equivalent comparisons are 2.26, 1.46, and 0.35 lg/g. Low concentrations of other pesticides (hexachlorobenzene, mirex, oxychlordane, and trans-nonachlor)
FIG. 4. Plasma Aroclor 1260 concentration (total plasma lipid adjusted) versus duration of residency in Canada for nine Bangladeshi and nine-Vietnamese fishers.
S163
CONTAMINANT EXPOSURE IN ASIAN FISHERS IN MONTREAL
TABLE 2 Plasma Organochlorine Pesticide Concentrations (Total Plasma Lipid Adjusted) in 9 Bangladeshi, 9 Vietnamese, and 25 High-Level Majorty-Community Sportfish Consumers accis-nona Aldrin b-BHC Chlordane Chlordane chlor p,p -DDE Unit of measurement Laboratory detection limit? Recommended tolerable limit?
0.02 100
0.03 NA
0.02 NA
0.02 NA
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 1 0.00 0.00 0.00 0.01
9 9 0.07 0.16 0.28 0.35
9 0 0.00 0.00 0.00 0.00
9 0 0.00 0.00 0.00 0.00
Number'tolerable limit?
0
NA
NA
NA
0.02 NA
p,p -DDT
lg/g total plasma lipids 0.02 0.03 200
HexachloroOxytransbenzene Mirex chlordane nonachlor
0.02 NA
0.02 NA
0.02 NA
0.02 NA
Bangladeshi 9 9 0.01 0.02 0.03 0.05
9 9 0.72 2.26 6.29 6.99
9 9 0.09 0.34 0.50 0.56
9 9 0.01 0.02 0.04 0.04
9 7 0.00 0.01 0.01 0.01
9 9 0.01 0.02 0.03 0.03
9 9 0.02 0.03 0.04 0.05
NA
0
0
NA
NA
NA
NA
9 9 0.01 0.16 1.02 1.31
9 9 0.01 0.01 0.02 0.02
9 5 0.00 0.00 0.01 0.01
9 7 0.00 0.01 0.02 0.04
9 9 0.01 0.02 0.05 0.09
0
NA
NA
NA
NA
25 25 0.01 0.02 0.03 0.07
25 25 0.00 0.01 0.04 0.15
25 25 0.01 0.01 0.03 0.05
25 25 0.00 0.02 0.05 0.10
NA
NA
NA
NA
Vietnamese Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 0 0.00 0.00 0.00 0.00
9 9 0.01 0.05 0.20 0.22
9 0 0.00 0.00 0.00 0.00
Number'tolerable limit?
0
NA
NA
9 0 0.00 0.00 0.00 0.00
9 7 0.00 0.01 0.02 0.03
NA
NA
9 9 0.13 1.46 12.3 19.2 0
High-level local consumers Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value Number'tolerable limit?
25 25 0 24 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.03 0
NA
25 0 0.00 0.00 0.00 0.00
25 0 0.00 0.00 0.00 0.00
25 5 0.00 0.00 0.01 0.02
NA
NA
NA
25 25 0.01 0.35 1.22 3.41 0
25 25 0.00 0.01 0.03 0.04 0
?Based on nonadjusted measurements (lg/L).
were detected in both the Bangladeshis and Vietnamese, at levels comparable to those found for the majority-community consumers (Fig. 5). An inverse relationship was shown for plasma p,p -DDT versus years of residency in Canada for the Bangladeshi (r2"0.60, P"0.01) (Fig. 6), but not for the Vietnamese participants. Regressed by itself, age also related to plasma p,p -DDT levels in Bangladeshi participants (r2"0.51, P"0.031). When age and years of residence in Canada were regressed simultaneously, only the latter related significantly to plasma p,p -DDT (model r2"0.71, P"0.018). No clear relationship was shown for plasma p,p -DDE or b-BHC versus years of residency in Canada for either community.
DISCUSSION
This small, exploratory study was based on a convenience sample of self-declared St. Lawrence River
sportfishers of Bangladeshi and Vietnamese origin. Our intent was to pilot a study design to be applied to many more members of these and other Asian communities resident in Montreal. Our measurements suggest a pattern of chemical contaminant exposure different in both kind and degree from that of local majority-community sportfishers who regularly eat their catch. Higher hair mercury concentrations among Asian consumers are consistent with our dietary assessment suggesting that these groups eat more fish overall than do even ardent majority-community sportfish consumers (Shatenstein, 1998). Urinary arsenic concentrations could reflect elevated current consumption of both shellfish and white rice, items identified as major contributors to arsenic exposure in the U.S. diet (MacIntosh, et al., 1997) and consumed in appreciable quantities by Bangladeshi and Vietnamese participants (Shatenstein, 1998). In particular, these Asian-origin sportfishers show higher tissue burdens of certain PCBs, p,p -DDT,
S164
KOSATSKY ET AL.
FIG. 5. Selected organochloride pesticides (total plasma lipid adjusted) among Bangladeshi, Vietnamese, and majority-community St. Lawrence River sportfishers classed as High-level consumers.
p,p -DDE, and b-BHC than their non-Asian neighbors. This relative difference in tissue burden is greater for the more recently arrived Bangladeshis. For the latter group, levels of exposure to DDE/DDT and b-BHC in some cases approach the range of concern for health (WHO, 1982). As reported by Shatenstein et al. (1998), Asian sportfishers active
on the St. Lawrence River do not demonstrate patterns of species choice, fish organ choice, or preparation techniques sufficiently different from those of majority-community fishers to offer a reasonable explanation for the observed differences in tissue contaminant concentrations. The finding that certain organochlorine substances are present in higher
FIG. 6. Plasma DDT concentration (total plasma lipid adjusted) versus duration of residency in Canada for nine Bangladeshi and nine Vietnamese fishers.
CONTAMINANT EXPOSURE IN ASIAN FISHERS IN MONTREAL
concentrations in the Asian sportfishers while others (mirex, chlordane, and cis-nonachlor, for example) are not suggests that observed tissue pesticide differences may be due to factors other than consumption of St. Lawrence River fish. The decline in plasma p,p -DDT concentration with years of residency in Canada suggests that exposure may have occurred during the Bangladeshis’ tenure in their country of origin. DDT and b-BHC are in common use on the Indian subcontinent (Kashyap, et al., 1994), but not in Canada or the United States; blood DDT concentrations in Indian vegetarian adults have been found to be in the 135—250 lg/L range with equivalent concentrations for b-BHC of 50—80 lg/L. Kashyap suggests that the use in India of DDT and BHC for the control of malaria leads to the contamination of cow’s milk, food grains, and vegetables. High levels of DDT and b-BHC in breast milk samples of Hong Kong residents are thought to relate to the importation of contaminated foodstuffs from China (Ip, 1990). As early as 1971, Radomski et al. (1971) found that Taiwanese studying in the United States had higher plasma b-BHC concentrations than U.S. residents (11.6$5.6 versus 1.4$0.46 lg/L). Future assessments should include these and other pesticides in immigrants to North America from various Asian countries, among both sportfishers and persons who do not consume local sportfish. The positive, albeit somewhat tenuous, correlation of PCB concentrations with years of residency in Canada among the Bangladeshis suggests uptake which has occurred locally. The size of our study and the wide variety of imported fish eaten by our study participants are insufficient evidence to relate increased plasma PCB concentrations over time to consumption of St. Lawrence River fish. Further, this phenomenon was not seen in the Vietnamese participants. We feel that assessment of PCB congener profiles along with an investigation of possible sources is warranted among Bangladeshis and other Asian groups resident in Montreal.
S165
ACKNOWLEDGMENTS This study was funded by the Health Component of the St. Lawrence Action Plan—Vision 2000, Health Canada; Contract H4078-4-C754/01-SS. We express our thanks to Bangladeshi and Vietnamese participants, to Sylvie Nadon, Bernard-Simon Leclerc, Moshrafa Moswar, Iftekar Uzzaman, Van Thanh Hotong, project field workers, and to Carmen Tremblay, study nurse.
REFERENCES Brown, J. F., and Lawton, R. W. (1984). Polychlorinated biphenyl (PCB) partitioning between adipose tissue and serum. Bull. Environ. Contam. Toxicol. 33, 277—280. Health Protection Branch (1986). Health Canada. Foods Directorate memorandum. Ottawa, Ontario, Canada. Hornung, R. W., and Reed, L. D. (1990). Estimation of average concentration in the presence of nondetectable values. Appl. Occup. Environ. Hyg. 5(1), 46—51. Ip, H. M. H. (1990). Chlorinated pesticides in foodstuffs in Hong Kong. Arch. Environ. Contam. Toxicol. 19, 291—296. Kashyap, R., Iyer, L. R., and Singh, M. M. (1994). Evaluation of daily dietary intake of dichloro-diphenyl trichloroethane (DDT) and benzene hexachloride (BHC) in India. Arch. Environ. Health. 49(1), 63—66. Kosatsky, T., Przybysz, R., Shatenstein, B., Weber, J.-P., and Armstrong, B. (1999). Fish consumption and contaminant exposure among Montreal-area sportfishers: Pilot study. Environ. Res. 80, S150—S158. MacIntosh, D. L., Williams, P. L., Hunter, D. J. et al. (1997). Evaluation of a food frequency questionnaire-food composition approach for estimating dietary intake of inorganic arsenic and methylmercury. Cancer Epidemiol. Biomark. Prev. 6, 1043—1050. Shatenstein, B., Kosatsky, T., Tapia, M., Nadon, S., and Leclerc, B.-S. (1999). Exploratory assessment of fish consumption among Asian-origin sportfishers on the St. Lawrence River in the Montreal region. Environ. Res. 80, S57—S70. Radomski, J. L., Deichman, W. B., Rey, A. A., et al. (1971). Human pesticide blood levels as measure of body burden and pesticide exposure. Toxicol. Appl. Pharm. 20, 175—185. WHO Technical Report Series (1982). ‘‘Recommended HealthBased Limits in Occupational Exposure to Pesticides.’’ World Health Organization. Geneva. Cited in Kaloyanova, F. P., and ElBatawi, M. A. ‘‘Human Toxicology of Pesticides,’’ p. 91. CRC Press, Boca Raton, FL, 1991.
Contaminant Exposure in Montrealers of Asian Origin Fishing the St. Lawrence River: Exploratory Assessment1 Tom Kosatsky,* - Raymond Przybysz,* Bryna Shatenstein,* Jean-Philippe Weber,- and Ben Armstrong‡ *Occupational and Environmental Health, Montreal Public Health Program, 1301 Sherbrooke East, Montreal, Quebec H2L 1M3, Canada, and Department of Occupational Health, McGill University, Montreal, Quebec, Canada; -Quebec Toxicology Center, Montreal, Quebec, Canada; and ‡London School of Hygiene, London, England Received December 22, 1997
and recency of arrival in Canada was found for the Bangladeshis. These data suggest a distinct pattern of tissue organochlorines, which we postulate relates to exposure prior to arrival in Canada and perhaps to the ongoing consumption of foods (other than St. Lawrence River sportfish) specific to these groups. 1999 Academic Press Key Words: Asians; DDT; PCB; sportfish; St. Lawrence.
Fishing and fish consumption are widely practiced among members of certain ethnocultural groups. Informal assessment led us to ascribe high levels of consumption of locally caught sportfish to Montrealers of Asian origin and to hypothesize that their choices of species and fish organs differ from those of the majority group. An exploratory assessment of contaminant bioindicators reflective of St. Lawrence River fish consumption was conducted in late 1995 among nine Vietnamese and nine Bangladeshi Montreal sportfishers identified by community contacts. Vietnamese participants, six men and three women, were 27—70 (median 36) years of age and had immigrated to Canada 3—20 (median 7) years earlier. In contrast, the nine Bangladeshi males aged 28–41 (median 34) years had been in Canada for 2–13 (median 4) years. Bioindicator concentrations among Bangladeshi and Vietnamese participants are compared to those found for majority-community Montreal-area highlevel consumers recruited on the St. Lawrence River during winter 1995. All results are presented as the median and 90th percentile. Hair mercury concentrations were higher for both Vietnamese (1.2, 4.6 lg/g) and Bangladeshis (1.1, 2.3 lg/g) than for majority-community sportfishers (0.7, 1.9 lg/g). Certain organochlorine levels, specifically total PCB (estimated by plasma Aroclor 1260), p,p -DDT, p,p -DDE, and B-BHC, were highest in the Bangladeshis compared to Vietnamese and to majority-community sportfishers. In contrast, plasma levels of other pesticides were low in all three groups, including mirex, chlordane, and cis-nonachlor. A correlation between plasma p,p -DDT levels
INTRODUCTION
An exploratory study of patterns of fish consumption and exposure to chemical substances potentially derived from fish was conducted in the fall of 1995 among adult Asian-origin sportfishers resident in the Montreal region. Preliminary assessment by our group had suggested that fishing practices and fish consumption patterns among Asian communities in Montreal might convey risk of excessive exposure to St. Lawrence River contaminants. Specifically, we wondered if frequent sportfish consumption, preference for bottom-feeding species such as carp and eel, and consumption of organ meats might occur. Participant recruitment and community and individuallevel nutritional assessment are described in a companion paper by Shatenstein et al. (1998). Here, we present tissue concentrations of mercury, arsenic, and certain organochlorine compounds in a pilot study of Vietnamese and Bangladeshi sportfishers living in Montreal and fishing the St. Lawrence River. METHODS
This study was funded by the Health Component of the St. Lawrence Action Plan-Vision 2000, Health Canada, Main Building, Room 0301 A1, Tunney’s Pasture, Ottawa, Ontario, K1A 0K9. The study protocol was approved by the Clinical Research Ethics Committee of Maisonneuve-Rosemont Hospital, Montreal.
Preliminary discussions with representatives of several Asian communities living in Montreal indicated that the city’s Vietnamese and Bangladeshi S159 0013-9351/99 $30.00 Copyright 1999 by Academic Press All rights of reproduction in any form reserved.
S160
KOSATSKY ET AL.
communities include many individuals who fish the nearby St. Lawrence River and might participate in an assessment of their sportfishing practices and of their exposure to contaminants derived from sportfish. Contact with community groups and personal recruitment by study resource persons who were members of Montreal’s Vietnamese and Bangladeshi communities led to the enrollment of nine Vietnamese (three of whom were women) and nine Bangladeshi (all men) sportfishers. Samples of blood and hair were collected during October—December 1995. Blood collection followed an overnight fast. Total mercury was analyzed for the most proximal hair centimeter by cold vapor atomic absorption spectrometry (Pharmacia Model 120). Inorganic arsenic was extracted from urine following complexation with potassium iodide; predigestion with sodium persulfate converted total to inorganic arsenic. Total urinary and inorganic arsenic were analyzed by graphite furnace atomic absorption spectrometry (Perkin Elmer Model 5100); both measurements were corrected for creatinine. Plasma was analyzed for 14 PCB congeners and for organochlorine pesticides using gas chromatography with electron capture. Organochlorine analyses have been corrected for total plasma lipid levels, as described by Brown and Lawton (1984). An Aroclor 1260 index was calculated as five times the sum of congeners 138 and 153. All measurements below the limit of detection (LOD) were replaced by the value of LOD/(2 (Hornung and Reed, 1990). The lowest, highest, median, and 90th percentile values are presented for each contaminant measured. A standardized comparison of PCB congener and pesticide results is presented by comparing ratios of the 25th, 50th, and 75th percentile concentrations for each contaminant as measured in the Vietnamese and Bangladeshis to the 50th percentile concentration as measured in a group of 25 high-level Montreal-area ice-fishers who are themselves described separately in this issue (Kosatsky et al., 1998). Linear regressions relate selected plasma organochlorine concentrations to participants’ age and to years of residency in Canada.
FIG. 1. Total hair mercury (cm 0—1) measured for Bangladeshi, Vietnamese, and majority-community St. Lawrence River sportfishers.
area sportfish consumers recruited during winter 1995 (0.73, 1.88 lg/g) (Fig. 1). Inorganic and total urinary arsenic concentrations (creatinine adjusted) were higher for Bangladeshi (medians 26.7 and 54.8 lg/g) than for Vietnamese fishers (medians 14.0 and 39.7 lg/g) (Fig. 2).
RESULTS
Sociodemographic characteristics as well as attributes of fish consumption are presented separately for the nine Vietnamese and nine Bangladeshi participants (Shatenstein et al., 1998). Hair mercury concentrations were somewhat higher among Vietnamese (median 1.23 lg/g, 90th percentile 4.62 lg/g) than among Bangladeshi participants (1.07, 2.29 lg/g) or high-level Montreal-
FIG. 2. Urinary arsenic (creatinine adjusted) measured for Bangladeshi and Vietnamese residents of Montreal fishing the St. Lawrence River.
S161
CONTAMINANT EXPOSURE IN ASIAN FISHERS IN MONTREAL
1.16 lg/g for the Bangladeshi participants and 0.59 lg/g for the Vietnamese compared to 0.77 lg/g for the local high-level sportfish consumers. No Bangladeshi or Vietnamese participant was found to have an Aroclor 1260 index greater than the Health Canada recommended limit of 5 lg/L for women of reproductive age or 20 lg/L for the general population (not adjusted for total plasma lipids) (Health Protection Branch, 1986). Comparison of standardized ratios of specific PCB congeners suggests that the Bangladeshis show particular elevations for lower-numbered congeners (Fig. 3). Years of residence in Canada correlated with their plasma Aroclor 1260 index for the nine Bangladeshi participants (r2"0.64, influenced largely by one extreme data point) but not for the Vietnamese (Fig. 4).
Inorganic arsenic alone was measured in 25 highlevel Montreal-area fishers; urinary arsenic was detected in a single member of this group. Detectable concentrations were found for all 14 PCB congeners among at least some Bangladeshi participants and (except for congener 128) among at east some Vietnamese. For congener 128, fewer than 2/3 Bangladeshis had detectable plasma concentrations, as was the case for congeners 52, 101, and 105 among the Vietnamese (Table 1). Median concentrations for all congeners were higher among the Bangladeshi participants than among the Vietnamese. Further, among the Bangladeshi, concentrations of all congeners were as high as or higher than those measured in local majority-community high-level sportfish consumers. Median Aroclor 1260 concentrations (total plasma lipid adjusted) were
TABLE 1 Plasma PCB Congener Concentrations (Total Plasma Lipid Adjusted) in 9 Bangladeshi, 9 Vietnamese, and 25 High-Level Majorty-Community Sportfish Consumers Aroclor 1260
PCB congener
Nonadj. Adjusted 28
52
99
101
105
118
128
138
153
156
170
180
183
187
Unit of measurement Laboratory detection limit? Recommended tolerable limit@
lg/L 0.2 5/20
&&&&&&&&&&&&&& lg/g total plasma lipids &&&&&&&&&&&&&&&& &&&&&&&&&&&&&&&&&&& 0.02 &&&&&&&&&&&&&&&&&&&& &&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&&&
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 9 1.80 7.82 14.7 19.4
Number'tolerable limit@
0/0
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 9 1.17 4.41 6.61 9.75
Number'tolerable limit@
0/0
&&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&&
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
25 25 2.61 5.31 7.61 94.5
25 25 0.32 0.77 1.50 8.67
Number'tolerable limit@
1/1
&&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&&
&&&&&&&&& Bangladeshi &&&&&&&&&&&&&&&&&&&&&&&&&&& 9 9 0.33 1.16 1.89 3.51
9 9 0.01 0.01 0.02 0.03
9 9 0.00 0.01 0.02 0.04
9 9 0.01 0.03 0.05 0.06
9 9 0.00 0.02 0.03 0.03
9 8 0.00 0.02 0.03 0.03
9 9 0.01 0.06 0.09 0.14
9 3 0.00 0.00 0.00 0.01
9 9 0.03 0.10 0.16 0.29
9 9 0.04 0.12 0.20 0.38
9 8 0.00 0.01 0.02 0.05
9 9 0.01 0.03 0.06 0.11
9 9 0.02 0.07 0.13 0.27
9 8 0.00 0.02 0.03 0.04
9 9 0.01 0.04 0.09 0.17
&&&&&&&&&&&&&&&&&&& NA &&&&&&&&&&&&&&&&&&&& Vietnamese 9 9 0.21 0.59 0.82 1.14
9 6 0.00 0.00 0.01 0.04
9 3 0.00 0.00 0.01 0.01
9 9 0.00 0.01 0.01 0.02
9 5 0.00 0.00 0.00 0.00
9 5 0.00 0.00 0.01 0.01
9 9 0.00 0.02 0.03 0.04
9 0 0.00 0.00 0.00 0.00
9 9 0.02 0.05 0.07 0.09
9 9 0.02 0.07 0.09 0.13
9 8 0.00 0.01 0.02 0.02
9 9 0.01 0.02 0.03 0.04
9 9 0.02 0.04 0.08 0.11
9 7 0.00 0.01 0.01 0.02
9 9 0.01 0.02 0.04 0.06
High-level local consumers 25 8 0.00 0.00 0.01 0.17
25 2 0.00 0.00 0.00 0.02
25 25 0.01 0.02 0.04 0.33
25 8 0.00 0.00 0.01 0.01
25 17 0.00 0.01 0.02 0.12
25 24 0.00 0.03 0.11 0.43
25 2 0.00 0.00 0.01 0.01
25 25 0.02 0.07 0.12 0.78
25 25 0.04 0.08 0.17 0.89
25 25 0.01 0.01 0.03 0.13
25 25 0.01 0.02 0.06 0.19
25 25 0.02 0.06 0.18 0.51
25 13 0.00 0.00 0.02 0.08
25 25 0.01 0.02 0.07 0.32
?Based on nonadjusted measurements (lg/L). @Health Canada’s Aroclor 1260 recommended tolerable limit (based on nonadjusted measurements): 5 lg/L for women of reproductive age/20 lg/L for the general population.
S162
KOSATSKY ET AL.
FIG. 3. Selected PCB congeners (total plasma lipid adjusted) among Bangladeshi, Vietnamese, and majority-community St. Lawrence River sportfishers classed as High-level consumers.
Among the organochlorine pesticides analyzed, two (a- and c-chlordane) were detected in none of the participants, while aldrin was detected in only one (Table 2). Levels of plasma p,p -DDT, p,p -DDE, and b-benzene hexachloride (b-BHC) were markedly higher in Bangladeshi and in Vietnamese participants than in majority-community ice-fishers (Kosatsky et al., 1998). Specific comparisons include
median p,p -DDT concentrations of 0.34 lg/g among the Bangladeshi, 0.16 lg/g among the Vietnamese, and 0.01 lg/g among the high-level majority-community sportfish consumers. For p,p -DDE, (a more stable breakdown product of p,p -DDT), the equivalent comparisons are 2.26, 1.46, and 0.35 lg/g. Low concentrations of other pesticides (hexachlorobenzene, mirex, oxychlordane, and trans-nonachlor)
FIG. 4. Plasma Aroclor 1260 concentration (total plasma lipid adjusted) versus duration of residency in Canada for nine Bangladeshi and nine-Vietnamese fishers.
S163
CONTAMINANT EXPOSURE IN ASIAN FISHERS IN MONTREAL
TABLE 2 Plasma Organochlorine Pesticide Concentrations (Total Plasma Lipid Adjusted) in 9 Bangladeshi, 9 Vietnamese, and 25 High-Level Majorty-Community Sportfish Consumers accis-nona Aldrin b-BHC Chlordane Chlordane chlor p,p -DDE Unit of measurement Laboratory detection limit? Recommended tolerable limit?
0.02 100
0.03 NA
0.02 NA
0.02 NA
Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 1 0.00 0.00 0.00 0.01
9 9 0.07 0.16 0.28 0.35
9 0 0.00 0.00 0.00 0.00
9 0 0.00 0.00 0.00 0.00
Number'tolerable limit?
0
NA
NA
NA
0.02 NA
p,p -DDT
lg/g total plasma lipids 0.02 0.03 200
HexachloroOxytransbenzene Mirex chlordane nonachlor
0.02 NA
0.02 NA
0.02 NA
0.02 NA
Bangladeshi 9 9 0.01 0.02 0.03 0.05
9 9 0.72 2.26 6.29 6.99
9 9 0.09 0.34 0.50 0.56
9 9 0.01 0.02 0.04 0.04
9 7 0.00 0.01 0.01 0.01
9 9 0.01 0.02 0.03 0.03
9 9 0.02 0.03 0.04 0.05
NA
0
0
NA
NA
NA
NA
9 9 0.01 0.16 1.02 1.31
9 9 0.01 0.01 0.02 0.02
9 5 0.00 0.00 0.01 0.01
9 7 0.00 0.01 0.02 0.04
9 9 0.01 0.02 0.05 0.09
0
NA
NA
NA
NA
25 25 0.01 0.02 0.03 0.07
25 25 0.00 0.01 0.04 0.15
25 25 0.01 0.01 0.03 0.05
25 25 0.00 0.02 0.05 0.10
NA
NA
NA
NA
Vietnamese Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value
9 0 0.00 0.00 0.00 0.00
9 9 0.01 0.05 0.20 0.22
9 0 0.00 0.00 0.00 0.00
Number'tolerable limit?
0
NA
NA
9 0 0.00 0.00 0.00 0.00
9 7 0.00 0.01 0.02 0.03
NA
NA
9 9 0.13 1.46 12.3 19.2 0
High-level local consumers Number of measurements Number'detection limit? Lowest value Median 90th percentile Highest value Number'tolerable limit?
25 25 0 24 0.00 0.01 0.00 0.02 0.00 0.03 0.00 0.03 0
NA
25 0 0.00 0.00 0.00 0.00
25 0 0.00 0.00 0.00 0.00
25 5 0.00 0.00 0.01 0.02
NA
NA
NA
25 25 0.01 0.35 1.22 3.41 0
25 25 0.00 0.01 0.03 0.04 0
?Based on nonadjusted measurements (lg/L).
were detected in both the Bangladeshis and Vietnamese, at levels comparable to those found for the majority-community consumers (Fig. 5). An inverse relationship was shown for plasma p,p -DDT versus years of residency in Canada for the Bangladeshi (r2"0.60, P"0.01) (Fig. 6), but not for the Vietnamese participants. Regressed by itself, age also related to plasma p,p -DDT levels in Bangladeshi participants (r2"0.51, P"0.031). When age and years of residence in Canada were regressed simultaneously, only the latter related significantly to plasma p,p -DDT (model r2"0.71, P"0.018). No clear relationship was shown for plasma p,p -DDE or b-BHC versus years of residency in Canada for either community.
DISCUSSION
This small, exploratory study was based on a convenience sample of self-declared St. Lawrence River
sportfishers of Bangladeshi and Vietnamese origin. Our intent was to pilot a study design to be applied to many more members of these and other Asian communities resident in Montreal. Our measurements suggest a pattern of chemical contaminant exposure different in both kind and degree from that of local majority-community sportfishers who regularly eat their catch. Higher hair mercury concentrations among Asian consumers are consistent with our dietary assessment suggesting that these groups eat more fish overall than do even ardent majority-community sportfish consumers (Shatenstein, 1998). Urinary arsenic concentrations could reflect elevated current consumption of both shellfish and white rice, items identified as major contributors to arsenic exposure in the U.S. diet (MacIntosh, et al., 1997) and consumed in appreciable quantities by Bangladeshi and Vietnamese participants (Shatenstein, 1998). In particular, these Asian-origin sportfishers show higher tissue burdens of certain PCBs, p,p -DDT,
S164
KOSATSKY ET AL.
FIG. 5. Selected organochloride pesticides (total plasma lipid adjusted) among Bangladeshi, Vietnamese, and majority-community St. Lawrence River sportfishers classed as High-level consumers.
p,p -DDE, and b-BHC than their non-Asian neighbors. This relative difference in tissue burden is greater for the more recently arrived Bangladeshis. For the latter group, levels of exposure to DDE/DDT and b-BHC in some cases approach the range of concern for health (WHO, 1982). As reported by Shatenstein et al. (1998), Asian sportfishers active
on the St. Lawrence River do not demonstrate patterns of species choice, fish organ choice, or preparation techniques sufficiently different from those of majority-community fishers to offer a reasonable explanation for the observed differences in tissue contaminant concentrations. The finding that certain organochlorine substances are present in higher
FIG. 6. Plasma DDT concentration (total plasma lipid adjusted) versus duration of residency in Canada for nine Bangladeshi and nine Vietnamese fishers.
CONTAMINANT EXPOSURE IN ASIAN FISHERS IN MONTREAL
concentrations in the Asian sportfishers while others (mirex, chlordane, and cis-nonachlor, for example) are not suggests that observed tissue pesticide differences may be due to factors other than consumption of St. Lawrence River fish. The decline in plasma p,p -DDT concentration with years of residency in Canada suggests that exposure may have occurred during the Bangladeshis’ tenure in their country of origin. DDT and b-BHC are in common use on the Indian subcontinent (Kashyap, et al., 1994), but not in Canada or the United States; blood DDT concentrations in Indian vegetarian adults have been found to be in the 135—250 lg/L range with equivalent concentrations for b-BHC of 50—80 lg/L. Kashyap suggests that the use in India of DDT and BHC for the control of malaria leads to the contamination of cow’s milk, food grains, and vegetables. High levels of DDT and b-BHC in breast milk samples of Hong Kong residents are thought to relate to the importation of contaminated foodstuffs from China (Ip, 1990). As early as 1971, Radomski et al. (1971) found that Taiwanese studying in the United States had higher plasma b-BHC concentrations than U.S. residents (11.6$5.6 versus 1.4$0.46 lg/L). Future assessments should include these and other pesticides in immigrants to North America from various Asian countries, among both sportfishers and persons who do not consume local sportfish. The positive, albeit somewhat tenuous, correlation of PCB concentrations with years of residency in Canada among the Bangladeshis suggests uptake which has occurred locally. The size of our study and the wide variety of imported fish eaten by our study participants are insufficient evidence to relate increased plasma PCB concentrations over time to consumption of St. Lawrence River fish. Further, this phenomenon was not seen in the Vietnamese participants. We feel that assessment of PCB congener profiles along with an investigation of possible sources is warranted among Bangladeshis and other Asian groups resident in Montreal.
S165
ACKNOWLEDGMENTS This study was funded by the Health Component of the St. Lawrence Action Plan—Vision 2000, Health Canada; Contract H4078-4-C754/01-SS. We express our thanks to Bangladeshi and Vietnamese participants, to Sylvie Nadon, Bernard-Simon Leclerc, Moshrafa Moswar, Iftekar Uzzaman, Van Thanh Hotong, project field workers, and to Carmen Tremblay, study nurse.
REFERENCES Brown, J. F., and Lawton, R. W. (1984). Polychlorinated biphenyl (PCB) partitioning between adipose tissue and serum. Bull. Environ. Contam. Toxicol. 33, 277—280. Health Protection Branch (1986). Health Canada. Foods Directorate memorandum. Ottawa, Ontario, Canada. Hornung, R. W., and Reed, L. D. (1990). Estimation of average concentration in the presence of nondetectable values. Appl. Occup. Environ. Hyg. 5(1), 46—51. Ip, H. M. H. (1990). Chlorinated pesticides in foodstuffs in Hong Kong. Arch. Environ. Contam. Toxicol. 19, 291—296. Kashyap, R., Iyer, L. R., and Singh, M. M. (1994). Evaluation of daily dietary intake of dichloro-diphenyl trichloroethane (DDT) and benzene hexachloride (BHC) in India. Arch. Environ. Health. 49(1), 63—66. Kosatsky, T., Przybysz, R., Shatenstein, B., Weber, J.-P., and Armstrong, B. (1999). Fish consumption and contaminant exposure among Montreal-area sportfishers: Pilot study. Environ. Res. 80, S150—S158. MacIntosh, D. L., Williams, P. L., Hunter, D. J. et al. (1997). Evaluation of a food frequency questionnaire-food composition approach for estimating dietary intake of inorganic arsenic and methylmercury. Cancer Epidemiol. Biomark. Prev. 6, 1043—1050. Shatenstein, B., Kosatsky, T., Tapia, M., Nadon, S., and Leclerc, B.-S. (1999). Exploratory assessment of fish consumption among Asian-origin sportfishers on the St. Lawrence River in the Montreal region. Environ. Res. 80, S57—S70. Radomski, J. L., Deichman, W. B., Rey, A. A., et al. (1971). Human pesticide blood levels as measure of body burden and pesticide exposure. Toxicol. Appl. Pharm. 20, 175—185. WHO Technical Report Series (1982). ‘‘Recommended HealthBased Limits in Occupational Exposure to Pesticides.’’ World Health Organization. Geneva. Cited in Kaloyanova, F. P., and ElBatawi, M. A. ‘‘Human Toxicology of Pesticides,’’ p. 91. CRC Press, Boca Raton, FL, 1991.