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Dietary intake of PCDD and PCDF from food in Ontario, Canada
C h e m o s p h e r e , Vol.19, Nos.l-6, P r i n t e d in G r e a t B r i t a i n
DIETARY
INTAKE
pp 507-512,
OF PCDD AND
PCDF
1989
FROM FOOD
Birminghaml, B., T h o r p e I, B., Frank 2, R., F l e m i n g ±, G., A s h m a n , J., Wheeler3, J., Io
2. 3. 4.
0 0 4 5 - 6 5 3 5 / 8 9 $3.00 P e r g a m o n Press plc
IN ONTARIO,
+ .00
CANADA
C l e m e n t I, T o s i n e I, Ripley 2, B~D[, Ryan 4, J~J~
O n t a r i o M i n i s t r y of the Environment, Toronto, Ontario, Canada M4V IP5 A g r i c u l t u r a l L a b o r a t o r y S e r v i c e s Branch, O n t a r i o M i n i s t r y of A g r i c u l t u r e & Food, Guelph, Ontario, C a n a d a NIG 2WI Q u a l i t y and S t a n d a r d s Division, O n t a r i o M i n i s t r y of A g r i c u l t u r e & Food Toronto, Ontario, Canada M7A IB3 H e a l t h P r o t e c t i o n Branch, D e p a r t m e n t of National Health & W e l f a r e Ottawa, Ontario, C a n a d a KIA 0L2
ABSTRACT Due to public concern about p o l y c h l o r i n a t e d d i b e n z o - p - d i o x i n s (PCDD) and p o l y c h l o r i n a t e d d i b e n z o f u r a n s (PCDF) in the food supply, the O n t a r i o g o v e r n m e n t a n a l y s e d 25 c o m p o s i t e samples from ten food classes i n c l u d i n g meats, eggs, milk, fruit and vegetables. These samples included both locally p r o d u c e d and imported foods. E x t r a c t i o n and low r e s o l u t i o n mass s p e c t r o m e t r y (LRMS) analysis of the samples was p e r f o r m e d by a contract laboratory. Some extracts (Ontario p r o d u c e o n l y ) were p o o l e d and a n a l y s e d by high r e s o l u t i o n mass s p e c t r o m e t r y (HRMS) at the O n t a r i o D i o x i n F a c i l i t y to c o n f i r m the LRMS findings. E l a b o r a t e QA/QC p r o t o c o l s were p e r f o r m e d to ensure r e l i a b i l i t y of the a n a l y t i c a l results. No T4CDD, P5CDD, H6CDD, T 4 C D F or PsCDF residues were found at d e t e c t i o n limits of 0.i to 7 ppt. V e r y smal[ amounts (most near the d e t e c t i o n limit) of other h i g h e r c h l o r i n a t e d PCDD and PCDF were found in some foods. The results indicate neither w i d e s p r e a d nor e l e v a t e d levels of PCDD and PCDF in any food groups tested, nor are the results indicative of any p a r t i c u l a r source of c o n t a m i n a t i o n . To assess any h e a l t h impact, h u m a n food c o n s u m p t i o n patterns and p r e d i c t e d intake levels were used to e s t i m a t e current levels of exposure. Current levels of e x p o s u r e were e s t i m a t e d to be up to 23% of the Ontario m a x i m u m a l l o w a b l e daily intake of PCDD and PCDF. KEYWORDS lychlorinated dibenzo-p-dioxins (PCDD); p o l y c h l o r i n a t e d d i b e n z o f u r a n s ~ oPCDF); food; meat; eggs; milk; fruit; vegetables; e s t i m a t e d dietary intake. 1.0
INTRODUCTION
In recent years, p u b l i c concerns have been raised h a z a r d s of PCDD and PCDF in O n t a r i o food (Davies, MacP h e r s o n , 1986). They found h i g h levels of PCDD in a fruit c o m p o s i t e sample which mainly c o n t a i n e d some m e a s u r a b l e levels of PCDD and PCDF in samples and milk.
about the p o s s i b l e h e a l t h 1988; Davies and and PCDF (up to 6600 ppt) apples. They also found of vegetables, m e a t / e g g s
The O n t a r i o g o v e r n m e n t a n a l y s e d samples of O n t a r i o milk and apples and failed to find the levels of PCDD and PCDF r e p o r t e d by Davies and MacP h e r s o n , 1986. To further expand the O n t a r i o investigation, a joint T e c h n i c a l C o m m i t t e e of staff from the O n t a r i o M i n i s t r i e s of A g r i c u l t u r e & Food (OMAF) and E n v i r o n m e n t (MOE), with t e c h n i c a l advice from Health & W e l f a r e Canada, was formed in May 1986 to d e v e l o p and o v e r s e e an a n a l y t i c a l p r o g r a m for o r g a n o c h l o r i n e c o n t a m i n a n t s Ln the major foodstuffs a v a i l a b l e to O n t a r i o consumers. Food has only r e c e n t l y been i n v e s t i g a t e d as a p o t e n t i a l source of PCDD and PCDF. Data a v a i l a b l e in 1986 on b a s e l i n e levels of PCDD and PCDF in food were limited to foods such as freshwater fish (Ryan et al, 1984; MOE, 1986) and those k n o w n to be c o n t a m i n a t e d by c h l o r o p h e n o l i c residues (Ryan et al, 1984, 1985). 5O7
508
2.0
STUDY PLAN
The work plan was d i v i d e d into two phases: Phase I was d e s i g n e d to v a l i d a t e the c o m p a r a b i l i t y of the various methods used for analysing PCDD and PCDF in plant tlssues since no standard method was available. Phase I) 2)
II was the major component
of the study and included:
Selecting specific foods for analysis based on the average c o n s u m p t i o n patterns of Ontario residents (OMAF, 1985); and Where possible, c o m p a r i n g Ontario produce with the same food item imported into the province (OMAF, 1985).
In previous a n a l y t i c a l programs, problems have o c c u r r e d because of c o n t a m i n a t i o n in the analytical process. Extensive quality control measures were i n c o r p o r a t e d into this investigation. Details of the QA/QC are found in M O E / O M A F (1988). 2.1
S E L E C T I O N OF FOOD C O M M O D I T I E S
Six major animal and five major plant c o m m o d i t i e s that were readily a v a i l a b l e in June to August were selected (Table I). Raw milk samples as part of this study had previously been selected and a n a l y s e d in May 1986. TABLE i. LIST OF FOOD PRODUCTS SELECTED FOR SAMPLING OVER THE J U N E - A U G U S T PERIOD AND THEIR ORIGINS COMMODITY
SOURCE
B e e f - P r i m e Steaks Beef-Hamburger Pork-Chops Chicken-Broiler Eggs-Hen M i l k - F r e s h whole
Ontario/U.S. O n t a r i o / N e w Zealand Ontario/Quebec Ontario/Quebec/U.S. Ontario/U.S. Ontario
Apples-Fresh Peaches-Fresh Potatoes Tomatoes Wheat
O n t a r i o / P a c i f i c Coast/New Ontario/U.S. Ontario/P.E.I./U.S. Ontario/U.S. O n t a r i o / W e s t e r n Canada
York
The focus on sampling the June to August period was based on the s u g g e s t i o n s that the high PCDD and PCDF levels found by Davies and M a c P h e r s o n (1986) were due to airborne sources of c o n t a m i n a t i o n in the Great Lakes basin. In particular, incineration sources were suggested as the major origin. Therefore, this sampling period should provide Ontario c o m m o d i t i e s that have had maximum exposure to airborne contaminants. 3.0
ANALYTICAL
PROCEDURES
3.1
SAMPLE P R E P A R A T I O N AND STORAGE
Raw samples were d e l i v e r e d to the Ontario M i n i s t r y of the Environment, Dioxin facility for processing. Fruit and vegetable samples were not washed or peeled except for the potato samples which were washed to remove soil. R e p l i c a t e s of each sample were p r e p a r e d on equipment proved free of PCDD and PCDF and frozen until d e l i v e r y to the a n a l y t i c a l laboratory. 3.2
SAMPLE E X T R A C T I O N AND ANALYSIS:
PCDD AND PCDF
The analysis of food samples for PCDD and PCDF was performed under c o n t r a c t by the same l a b o r a t o r y that analysed food samples for Davies and MacPherson, 1986.
509
3.2.1
Phase
I: Method
Comparison
for PCDD
and
PCDF
in Apples
The work for Phase I of this study d e m o n s t r a t e d that the c o n t r a c t o r ' s e x i s t i n g m e t h o d o l o g y for PCDD and PCDF in apples produced results c o m p a r a b l e to those g e n e r a t e d by the Health & W e l f a r e Canada method. Therefore, the c o n t r a c t o r used their existing m e t h o d o l o g y for e x t r a c t i o n and a n a l y s i s of fruit and v e g e t a b l e samples. However, the e x t r a c t i o n method used by H e a l t h & W e l f a r e Canada was employed for analysis of the animal product samples. 3.2.2
Phase
II:
Analysis
of Food
for P C D D / P C D F
The a n a l y t i c a l results supplied by LRMS r e s u ] t e d in average d e t e c t i o n 15 ppt).
the c o n t r a c t o r limits between
which were o b t a i n e d using 1 and 4 ppt (range 0.i to
To reduce MDL O n t a r i o produce samples were pooled and r e - a n a l y s e d by HRMS (nominal r e s o l u t i o n I0,000) at the MOE Mass S p e c t r o m e t r y L a b o r a t o r y using the technique of Taguchi et al, 1988. 4.0
RESULTS
LRMS residue Table 2. TABLE
data
for PCDD
2. MAXIMUM
and PCDF
in animal
product
RESIDUES OF PCDD AND PCDF (pg/g - fresh weight)
Eggs
Beef
T4CDD P5CDD H6CDD H7CDD O8CDD
ND ND ND ND 8 (US
ND ND ND ND 24
T4CDF P5CDF H6CDF HTCDF OsCDF
ND ND 5 (US 7 (US 12 (US
ND ND ND ND ND
(US)
samples
IN ANIMAL
Hamburger
Pork
ND ND ND ND 3 (Ont)
ND ND ND ND ND
ND ND ND 15 210
ND ND ND ND ND
ND ND ND ND ND
ND ND ND ND ND
are
shown
in
SAMPLES
Chicken
(Que) (Que)
Positive values for certain samples are shown. For example, the U.S. egg sample c o n t a i n e d low levels of 08CDD , H6CDF , H7CDF and O8CDF. Low levels of OSCDD were found in U.S. beef and Ontario hamburger. Higher levels of HTCDD and O s C D D were found in chicken samples from Quebec. In an attempt to increase s e n s i t i v i t y and lower the MDL, some e x t r a c t s were p o o l e d and rerun under o p t i m i z e d HRMS conditions. D e t e c t i o n limits were lowered by a factor of i0 and in some cases, PCDD and PCDF r e s i d u e s were found at levels below those p r e v i o u s l y d e t e r m i n e d for individual samples. For example, trace amounts (0.03 to 3 ppt) of H7CDD , H6CDF and H7CDF were o b s e r v e d in the pooled egg, beef, chicken and pork samples. Table
3 shows
results
for the LRMS
analysis
of the plant
product
samples.
As before, PCDD and PCDF r e s i d u e s were n o n - d e t e c t a b l e in most cases. In most cases, the MDL was less than 1 ppt. D e t e c t a b l e levels in peaches and wheat were also ]ess than 1 ppt. Traces of O 8 C D D (i to 3 ppt) were found in all potato samples. Except for the 8 ppt OsCDD found in N.Y. apples, no PCDD or PCDF were d e t e c t e d in the apple samples. O n t a r i o produce samples were also pooled and r e - a n a l y s e d uslng HRMS o p t i m i z e d for greater sensitivity. Under these conditions, no further residues were found.
510
TABLE
3. M A X I M U M Potatoes
4.1
R E S I D U E S OF P C D D A N D P C D F (pg/g - f r e s h w e i g h t ) Apples
T4CDD P5CDD H6CDD H7CDD O8CDD
ND ND ND ND 3 (US)
ND ND ND ND 8
T4CDF P5CDF H6CDF H7CDF O8CDF
ND ND ND ND ND
ND ND ND ND ND
CALCULATED
DIETARY
Tomatoes
(NY)
INTAKES
IN P L A N T
Peaches
Wheat
ND ND ND ND ND
ND ND ND ND 0.6
ND ND ND ND 0.7
ND ND ND ND ND
ND ND ND ND ND
OF PCDD AND
(US)
SAMPLES
(West)
ND ND ND ND ND
PCDF
W h a t do t h e s e r e s u l t s m e a n ? In C a n a d a , f o o d s c o n t a i n i n g P C D D are c o n s i d e r e d a d u l t e r a t e d a n d not fit for sale ( F o o d a n d D r u g s A c t a n d R e g u l a t i o n s (1986)). F i s h c o n t a i n i n g less t h a n 2U ppt of 2 , 3 , 7 , 8 - T C D D are e x e m p t . T h e r e are no r e g u l a t i o n s for P C D F in foods. C u r r e n t l y O n t a r i o is c o l l a b o r a t i n g w i t h o t h e r p r o v i n c e s a n d the f e d e r a l g o v e r n m e n t to d e v e l o p n a t i o n a l g u i d e l i n e s for P C D D a n d P C D F in all environmental media. T h i s w o r k is b a s e d on a n e w m u l t i - m e d i a a p p r o a c h a n d h a s b e e n d e s c r i b e d ( B i r m i n g h a m et al, 1988, and G i l m a n et al, 1988). To p r o v i d e an e v a l u a t i o n of h e a l t h risk, an a n a l y s i s of c u r r e n t e s t i m a t e d e x p o s u r e s f r o m the d i e t c o m p a r e d w i t h the m a x i m u m a l l o w a b l e d a i l y i n t a k e is presented. T a b l e 4 s h o w s the c a l c u l a t e d d a i l y i n t a k e of P C D D a n d P C D F v i a r e s i d u e s in food f r o m the p r e s e n t study. T A B L E 4. C A L C U L A T E D D A I L Y I N T A K E OF P C D D A N D V I A R E S I D U E S IN F O O D F R O M C U R R E N T S T U D Y
FOOD GROUP
DAILY CONSUMPTION (g/person/day) 1 w h o l e wt
Beef Pork Poultry Eggs Milk Products Fruit Vegetables Wheat Based Products 1 _ Nutrition
Canada,
55.8 19 20 29 444 190 220 125
1977;
2,3,7,8TCDD EquivalwDts (pg T E Q Z / q whole wt~
PCDF
DAILY
INTAKE Pg TEQ/kg pg TEQ~ body person ~ weight
0.29 0.03 0.39 0.59 0.ii 0.004 0.002 0.0007
16.2 0.6 7.8 17.0 48.8 0.76 0.44 0.09
0.27 0.01 0.13 0.28 0.81 0.06 0.007 0.001
Total:
91.7
1.52
2 _ TEQ
= toxic
equivalent;
3 = 60 k g
adult
The r e c o m m e n d e d m a x i m u m a l l o w a b l e d a i l y i n t a k e for P C D D a n d P C D F f r o m all e x p o s u r e s is the t o x i c e q u i v a l e n t of i0 p g of 2 , 3 , 7 , 8 - T C D D / k g b o d y w e i g h t (MOE, 1985; B i r m i n g h a m , et al, 1988; G i l m a n , et a l , 1988). In this t a b l e 4, we h a v e u s e d N u t r i t i o n C a n a d a (1977) c o n s u m p t i o n f a c t o r s . E s t i m a t e s of the r e l a t i v e t o x i c i t y of o t h e r P C D D a n d P C D F to 2 , 3 , 7 , 8 - T C D D ( t o x i c i t y e q u i v a l e n t s or TEQ) w e r e c a l c u l a t e d u s i n g the r e c e n t l y p r o p o s e d i n t e r n a t i o n a l s c h e m e of t o x i c i t y e q u i v a l e n c e f a c t o r s (TEF). (Boddington, 1987; N o r d i s k M i n i s t e r r a d , 1988). W h e r e d a t a w e r e r e p o r t e d as ND t h e n r e s i d u e s are a s s u m e d to be a b s e n t . D a i l y i n t a k e is e x p r e s s e d as p g assumedTEQ/pers°ntobe andl~%_TEQ/kg body weight. A b s o r p t i o n b y the G.I. t r a c t was
511
The
following points
can be made
- the foods which c o n t r i b u t e d followed by eggs and beef.
from Table 4:
the most exposure
to PCDD and PCDF were milk,
- the total c o n t r i b u t i o n from the animal products pg T E Q / k g body weight (about 99% of the total). - the plant products 1% of the total).
contribute
to the daily
0.02 pg of TEQ/kg body weight
intake
is 1.5
per day
(about
- the total c a l c u l a t e d daily intake of PCDD and PCDF from food is 1.52 pg TEQ/kg body weight or about 15% of the maximum allowable intake from all sources. Fish were not analysed in the present study. To estimate the added c o n t r i b u t i o n from fresh water fish to dietary intake, a reasonable estimate of 0.28 pg TEQ/kg body weight per day has been made (Birmingham et al, 1988). This would bring the daily exposure to 1.8 pg TEQ/kg bo y ~ g h t (about 18% of the m a x i m u m allowable daily exposure). When c a l c u l a t e d daily intake of TEQ via PCDD and PCDF residues in food is calculated using the assumption that ND data are present at the minimum reported detection limit, food intake (including freshwater fish) can account for 23% of the maximum allowable daily intake of PCDD and PCDF.) CONCLUSIONS 1.
2.
3. 4.
5.
These results indicate that the fruit and vegetable samples a n a l y s e d are s u b s t a n t i a l l y free of most PCDD and PCDF, e s p e c i a l l y the more toxic tetra-, penta- and hexa- c h l o r i n a t e d forms. This is a significant finding as the samples were not peeled. Except for the potato samples, the samples were not washed either. The skins of fruit and v e g e t a b l e s would be a n t i c i p a t e d to contain PCDD and PCDF if there was uptake due to exposure from airborne p a r t i c u l a t e s or soil. Generally, very low levels of 08CDD were found in egg, chicken, beef, hamburger, potato, apple, peaches and wheat samples. Some chicken and egg samples c o n t a i n e d higher PCDD and PCDF residues. The presence of higher c h l o r i n a t e d PCDD and PCDF in animal products reflects the higher fat content of these samples and the l i p o p h i l i c i t y of PCDD and PCDF. Residue levels in O n t a r i o - g r o w n plant and animal products were lower than or comparable to the levels found in imported food. Overall, the residue levels found in this study are s u b s t a n t i a l l y less than those found in the Davies and M a c P h e r s o n (1986) report. Other recently published Canadian, German and U.S. food monitoring studies (Firestone, et al, 1986; Ryan, et al, 1985a; Mathar, et al, 1987) also indicate t h a ' ~ - ~ and PCDF resl u---d-~ are g e n e r a l l y non----~ectable, similar to the results from the present study, except in special cases of known p e n t a c h l o r o p h e n o l c o n t a m i n a t i o n (Ryan, et al, 1984; Ryan, et al, 1985). ~r6-od intake (including fresh water fish) is the largest human exposure pathway for PCDD and PCDF, accounting for 95% of the total exposure, or up to 23% of the maximum allowable daily intake.
In conclusion, this study shows that exposure to PCDD and PCDF from c o n s u m p t i o n of c o m m e r c i a l l y available food in Ontario is well below the m a x i m u m allowable daily intake of I0 pg TEQ/kg body weight. BIBLIOGRAPHY Birmingham, B., A. Gilman, D. Grant, J. Salminen, M. Boddington, B. Thorpe, I. wile, P. Toft and V. Armstrong. 1988. P C D D / P C D F M u l t i m e d i a Exposure Analysis for the Canadian Population: D e t a i l e d Exposure Estimation. Dioxin'88, Umea, Sweden. Boddington, M. Considerations.
1988. Final Plenary Session - Risk M a n a g e m e n t Dioxin '87, Las Vegas, U.S.A. Chemosphere. In press.
512
Davies, K. 1988. C o n c e n t r a t i o n s and dietary intakes of selected o r g a n o c h l o r i n e s , including PCBs, PCDDs and PCDFs in fresh food c o m p o s i t e s grown in Ontario, Canada. C h e m o s p h e r e 17: 263-276. Davies, K. and A.S. Macpherson, 1986. Human e x p o s u r e routes to selected p e r s i s t e n t toxic c h e m i c a l s in the G r e a t LaKes Basln: A case StUdy. ~'inal report to the Toxic S u b s t a n c e s Committee, Great LaKes W a t e r Quallty Board, I n t e r n a t i o n a l J o i n t Committee. (March 1986) Windsor, Ontario (unpublished). Firestone, D., R.A. Niemann, L.F. Schneider, J.R. Gridley, and D.E. Brown. 1986. Dioxin residues in fish and other foods. In: C h l o r i n a t e d dioxins and d i b e n z o f u r a n s in Perspective. C. Rappe, G. Choudhary, L. Keith (Editors). Lewls Publishers, Chelsea, Michigan. Gilman, A., B. Birmingham, D. Grant, J. Salminen, M. Boddington, B. Thorpe, I. Wile, P. Toft, V. Armstrong. 1988. P C D D / P C D F M u l t i m e d i a Exposure Analysis for the C a n a d i a n Population: Overview. Dioxin'88, Umea, Sweden. Mathar, W., H. Beck, K. Eckart, and R. Wittkowski. 1987. Body burden with PCDDs and from food intake in Germany. Dioxin '87, Las Vegas, U.S.A. Chemosphere. In press. M i n i s t r i e s of the Environment and Agriculture & Food. 1988. P o l [ c h l o r i n a t e d D i b e n z o - p - d i o x i n s and P o l [ c h l o r i n a t e d D i b e n z o f u r a n s other O r g a n o c h l o r i n e C o n t a m l n a n t s in Food. Nordisk Ministerrad. 143 pages.
1988.
Nordisk D i o x i n r i s k b e d o m n i n g .
Nutrition Canada. 1977. Food C o n s u m p t i o n P a t t e r n s Report. Canada, Health P r o t e c t i o n Branch. Ontario M i n i s t r y of Agriculture for Ontario. P u b l i c a t i o n 20.
and Food.
1985.
and
Copenhagen. Health & W e l f a r e
Agricultural
Statistics
Ontario M i n i s t r y of the Environment. 1985. Scientific Criteria D o c u m e n t for S t a n d a r d D e v e l o p m e n t N o . 4 - 8 4 - P o l ~ c h l o r i n a t e d D l b e n z o - p - d i o x i n s (PCDDs) and P o ± [ c h l o r l n a t e d ~ i b e n z o t u r a n s (PCDFs). Ontario M i n i s t r y of the Environment. Sportfish.
1986b.
Guide to Eating Ontario
Ryan, J.J., R. Lizotte, T. Sakuma, and B. Mori. 1985. C h l o r i n a t e d d i b e n z o - p - d i o x i n s , c h l o r i n a t e d dibenzofurans, and p e n t a c h l o r o p h e n o l in Canadian chicken and pork samples. J. Agric. Food Chem. 33: 1021-1026. Ryan, J.J., P.Y. Lau, J.C. Pilon, D. Lewis, H.A. McLeod, and A. Gervais. 1984. Incidence and Levels of 2 , 3 , 7 , 8 - T e t r a c h l o r o d i b e n z o - p - d i o x i n in Lake Ontario Commercial Fish. Environ. Sci. Technol. 18: 719-721. Taguchi, V., E.J. Reiner, D.T. Wang, O. Meresz and B. Hallas. 1988. High r e s o l u t i o n mass s p e c t r o m e t r i c d e t e r m i n a t i o n of p o l y c h l o r i n a t e d d i b e n z o - p - d i o x i n s and d i b e n z o f u r a n s using an a l t e r n a t i v e system. Anal. Chem. 60: 1429-1433. The Food and Dru~ Act and R e g u l a t i o n s with A m e n d m e n t s to D e c e m b e r r 1986. Q u e e n ' s Printers and C o n t r o l l e r ot Stationary. M z n i s t r y ot Supply and Services, Ottawa.
DIETARY
INTAKE
pp 507-512,
OF PCDD AND
PCDF
1989
FROM FOOD
Birminghaml, B., T h o r p e I, B., Frank 2, R., F l e m i n g ±, G., A s h m a n , J., Wheeler3, J., Io
2. 3. 4.
0 0 4 5 - 6 5 3 5 / 8 9 $3.00 P e r g a m o n Press plc
IN ONTARIO,
+ .00
CANADA
C l e m e n t I, T o s i n e I, Ripley 2, B~D[, Ryan 4, J~J~
O n t a r i o M i n i s t r y of the Environment, Toronto, Ontario, Canada M4V IP5 A g r i c u l t u r a l L a b o r a t o r y S e r v i c e s Branch, O n t a r i o M i n i s t r y of A g r i c u l t u r e & Food, Guelph, Ontario, C a n a d a NIG 2WI Q u a l i t y and S t a n d a r d s Division, O n t a r i o M i n i s t r y of A g r i c u l t u r e & Food Toronto, Ontario, Canada M7A IB3 H e a l t h P r o t e c t i o n Branch, D e p a r t m e n t of National Health & W e l f a r e Ottawa, Ontario, C a n a d a KIA 0L2
ABSTRACT Due to public concern about p o l y c h l o r i n a t e d d i b e n z o - p - d i o x i n s (PCDD) and p o l y c h l o r i n a t e d d i b e n z o f u r a n s (PCDF) in the food supply, the O n t a r i o g o v e r n m e n t a n a l y s e d 25 c o m p o s i t e samples from ten food classes i n c l u d i n g meats, eggs, milk, fruit and vegetables. These samples included both locally p r o d u c e d and imported foods. E x t r a c t i o n and low r e s o l u t i o n mass s p e c t r o m e t r y (LRMS) analysis of the samples was p e r f o r m e d by a contract laboratory. Some extracts (Ontario p r o d u c e o n l y ) were p o o l e d and a n a l y s e d by high r e s o l u t i o n mass s p e c t r o m e t r y (HRMS) at the O n t a r i o D i o x i n F a c i l i t y to c o n f i r m the LRMS findings. E l a b o r a t e QA/QC p r o t o c o l s were p e r f o r m e d to ensure r e l i a b i l i t y of the a n a l y t i c a l results. No T4CDD, P5CDD, H6CDD, T 4 C D F or PsCDF residues were found at d e t e c t i o n limits of 0.i to 7 ppt. V e r y smal[ amounts (most near the d e t e c t i o n limit) of other h i g h e r c h l o r i n a t e d PCDD and PCDF were found in some foods. The results indicate neither w i d e s p r e a d nor e l e v a t e d levels of PCDD and PCDF in any food groups tested, nor are the results indicative of any p a r t i c u l a r source of c o n t a m i n a t i o n . To assess any h e a l t h impact, h u m a n food c o n s u m p t i o n patterns and p r e d i c t e d intake levels were used to e s t i m a t e current levels of exposure. Current levels of e x p o s u r e were e s t i m a t e d to be up to 23% of the Ontario m a x i m u m a l l o w a b l e daily intake of PCDD and PCDF. KEYWORDS lychlorinated dibenzo-p-dioxins (PCDD); p o l y c h l o r i n a t e d d i b e n z o f u r a n s ~ oPCDF); food; meat; eggs; milk; fruit; vegetables; e s t i m a t e d dietary intake. 1.0
INTRODUCTION
In recent years, p u b l i c concerns have been raised h a z a r d s of PCDD and PCDF in O n t a r i o food (Davies, MacP h e r s o n , 1986). They found h i g h levels of PCDD in a fruit c o m p o s i t e sample which mainly c o n t a i n e d some m e a s u r a b l e levels of PCDD and PCDF in samples and milk.
about the p o s s i b l e h e a l t h 1988; Davies and and PCDF (up to 6600 ppt) apples. They also found of vegetables, m e a t / e g g s
The O n t a r i o g o v e r n m e n t a n a l y s e d samples of O n t a r i o milk and apples and failed to find the levels of PCDD and PCDF r e p o r t e d by Davies and MacP h e r s o n , 1986. To further expand the O n t a r i o investigation, a joint T e c h n i c a l C o m m i t t e e of staff from the O n t a r i o M i n i s t r i e s of A g r i c u l t u r e & Food (OMAF) and E n v i r o n m e n t (MOE), with t e c h n i c a l advice from Health & W e l f a r e Canada, was formed in May 1986 to d e v e l o p and o v e r s e e an a n a l y t i c a l p r o g r a m for o r g a n o c h l o r i n e c o n t a m i n a n t s Ln the major foodstuffs a v a i l a b l e to O n t a r i o consumers. Food has only r e c e n t l y been i n v e s t i g a t e d as a p o t e n t i a l source of PCDD and PCDF. Data a v a i l a b l e in 1986 on b a s e l i n e levels of PCDD and PCDF in food were limited to foods such as freshwater fish (Ryan et al, 1984; MOE, 1986) and those k n o w n to be c o n t a m i n a t e d by c h l o r o p h e n o l i c residues (Ryan et al, 1984, 1985). 5O7
508
2.0
STUDY PLAN
The work plan was d i v i d e d into two phases: Phase I was d e s i g n e d to v a l i d a t e the c o m p a r a b i l i t y of the various methods used for analysing PCDD and PCDF in plant tlssues since no standard method was available. Phase I) 2)
II was the major component
of the study and included:
Selecting specific foods for analysis based on the average c o n s u m p t i o n patterns of Ontario residents (OMAF, 1985); and Where possible, c o m p a r i n g Ontario produce with the same food item imported into the province (OMAF, 1985).
In previous a n a l y t i c a l programs, problems have o c c u r r e d because of c o n t a m i n a t i o n in the analytical process. Extensive quality control measures were i n c o r p o r a t e d into this investigation. Details of the QA/QC are found in M O E / O M A F (1988). 2.1
S E L E C T I O N OF FOOD C O M M O D I T I E S
Six major animal and five major plant c o m m o d i t i e s that were readily a v a i l a b l e in June to August were selected (Table I). Raw milk samples as part of this study had previously been selected and a n a l y s e d in May 1986. TABLE i. LIST OF FOOD PRODUCTS SELECTED FOR SAMPLING OVER THE J U N E - A U G U S T PERIOD AND THEIR ORIGINS COMMODITY
SOURCE
B e e f - P r i m e Steaks Beef-Hamburger Pork-Chops Chicken-Broiler Eggs-Hen M i l k - F r e s h whole
Ontario/U.S. O n t a r i o / N e w Zealand Ontario/Quebec Ontario/Quebec/U.S. Ontario/U.S. Ontario
Apples-Fresh Peaches-Fresh Potatoes Tomatoes Wheat
O n t a r i o / P a c i f i c Coast/New Ontario/U.S. Ontario/P.E.I./U.S. Ontario/U.S. O n t a r i o / W e s t e r n Canada
York
The focus on sampling the June to August period was based on the s u g g e s t i o n s that the high PCDD and PCDF levels found by Davies and M a c P h e r s o n (1986) were due to airborne sources of c o n t a m i n a t i o n in the Great Lakes basin. In particular, incineration sources were suggested as the major origin. Therefore, this sampling period should provide Ontario c o m m o d i t i e s that have had maximum exposure to airborne contaminants. 3.0
ANALYTICAL
PROCEDURES
3.1
SAMPLE P R E P A R A T I O N AND STORAGE
Raw samples were d e l i v e r e d to the Ontario M i n i s t r y of the Environment, Dioxin facility for processing. Fruit and vegetable samples were not washed or peeled except for the potato samples which were washed to remove soil. R e p l i c a t e s of each sample were p r e p a r e d on equipment proved free of PCDD and PCDF and frozen until d e l i v e r y to the a n a l y t i c a l laboratory. 3.2
SAMPLE E X T R A C T I O N AND ANALYSIS:
PCDD AND PCDF
The analysis of food samples for PCDD and PCDF was performed under c o n t r a c t by the same l a b o r a t o r y that analysed food samples for Davies and MacPherson, 1986.
509
3.2.1
Phase
I: Method
Comparison
for PCDD
and
PCDF
in Apples
The work for Phase I of this study d e m o n s t r a t e d that the c o n t r a c t o r ' s e x i s t i n g m e t h o d o l o g y for PCDD and PCDF in apples produced results c o m p a r a b l e to those g e n e r a t e d by the Health & W e l f a r e Canada method. Therefore, the c o n t r a c t o r used their existing m e t h o d o l o g y for e x t r a c t i o n and a n a l y s i s of fruit and v e g e t a b l e samples. However, the e x t r a c t i o n method used by H e a l t h & W e l f a r e Canada was employed for analysis of the animal product samples. 3.2.2
Phase
II:
Analysis
of Food
for P C D D / P C D F
The a n a l y t i c a l results supplied by LRMS r e s u ] t e d in average d e t e c t i o n 15 ppt).
the c o n t r a c t o r limits between
which were o b t a i n e d using 1 and 4 ppt (range 0.i to
To reduce MDL O n t a r i o produce samples were pooled and r e - a n a l y s e d by HRMS (nominal r e s o l u t i o n I0,000) at the MOE Mass S p e c t r o m e t r y L a b o r a t o r y using the technique of Taguchi et al, 1988. 4.0
RESULTS
LRMS residue Table 2. TABLE
data
for PCDD
2. MAXIMUM
and PCDF
in animal
product
RESIDUES OF PCDD AND PCDF (pg/g - fresh weight)
Eggs
Beef
T4CDD P5CDD H6CDD H7CDD O8CDD
ND ND ND ND 8 (US
ND ND ND ND 24
T4CDF P5CDF H6CDF HTCDF OsCDF
ND ND 5 (US 7 (US 12 (US
ND ND ND ND ND
(US)
samples
IN ANIMAL
Hamburger
Pork
ND ND ND ND 3 (Ont)
ND ND ND ND ND
ND ND ND 15 210
ND ND ND ND ND
ND ND ND ND ND
ND ND ND ND ND
are
shown
in
SAMPLES
Chicken
(Que) (Que)
Positive values for certain samples are shown. For example, the U.S. egg sample c o n t a i n e d low levels of 08CDD , H6CDF , H7CDF and O8CDF. Low levels of OSCDD were found in U.S. beef and Ontario hamburger. Higher levels of HTCDD and O s C D D were found in chicken samples from Quebec. In an attempt to increase s e n s i t i v i t y and lower the MDL, some e x t r a c t s were p o o l e d and rerun under o p t i m i z e d HRMS conditions. D e t e c t i o n limits were lowered by a factor of i0 and in some cases, PCDD and PCDF r e s i d u e s were found at levels below those p r e v i o u s l y d e t e r m i n e d for individual samples. For example, trace amounts (0.03 to 3 ppt) of H7CDD , H6CDF and H7CDF were o b s e r v e d in the pooled egg, beef, chicken and pork samples. Table
3 shows
results
for the LRMS
analysis
of the plant
product
samples.
As before, PCDD and PCDF r e s i d u e s were n o n - d e t e c t a b l e in most cases. In most cases, the MDL was less than 1 ppt. D e t e c t a b l e levels in peaches and wheat were also ]ess than 1 ppt. Traces of O 8 C D D (i to 3 ppt) were found in all potato samples. Except for the 8 ppt OsCDD found in N.Y. apples, no PCDD or PCDF were d e t e c t e d in the apple samples. O n t a r i o produce samples were also pooled and r e - a n a l y s e d uslng HRMS o p t i m i z e d for greater sensitivity. Under these conditions, no further residues were found.
510
TABLE
3. M A X I M U M Potatoes
4.1
R E S I D U E S OF P C D D A N D P C D F (pg/g - f r e s h w e i g h t ) Apples
T4CDD P5CDD H6CDD H7CDD O8CDD
ND ND ND ND 3 (US)
ND ND ND ND 8
T4CDF P5CDF H6CDF H7CDF O8CDF
ND ND ND ND ND
ND ND ND ND ND
CALCULATED
DIETARY
Tomatoes
(NY)
INTAKES
IN P L A N T
Peaches
Wheat
ND ND ND ND ND
ND ND ND ND 0.6
ND ND ND ND 0.7
ND ND ND ND ND
ND ND ND ND ND
OF PCDD AND
(US)
SAMPLES
(West)
ND ND ND ND ND
PCDF
W h a t do t h e s e r e s u l t s m e a n ? In C a n a d a , f o o d s c o n t a i n i n g P C D D are c o n s i d e r e d a d u l t e r a t e d a n d not fit for sale ( F o o d a n d D r u g s A c t a n d R e g u l a t i o n s (1986)). F i s h c o n t a i n i n g less t h a n 2U ppt of 2 , 3 , 7 , 8 - T C D D are e x e m p t . T h e r e are no r e g u l a t i o n s for P C D F in foods. C u r r e n t l y O n t a r i o is c o l l a b o r a t i n g w i t h o t h e r p r o v i n c e s a n d the f e d e r a l g o v e r n m e n t to d e v e l o p n a t i o n a l g u i d e l i n e s for P C D D a n d P C D F in all environmental media. T h i s w o r k is b a s e d on a n e w m u l t i - m e d i a a p p r o a c h a n d h a s b e e n d e s c r i b e d ( B i r m i n g h a m et al, 1988, and G i l m a n et al, 1988). To p r o v i d e an e v a l u a t i o n of h e a l t h risk, an a n a l y s i s of c u r r e n t e s t i m a t e d e x p o s u r e s f r o m the d i e t c o m p a r e d w i t h the m a x i m u m a l l o w a b l e d a i l y i n t a k e is presented. T a b l e 4 s h o w s the c a l c u l a t e d d a i l y i n t a k e of P C D D a n d P C D F v i a r e s i d u e s in food f r o m the p r e s e n t study. T A B L E 4. C A L C U L A T E D D A I L Y I N T A K E OF P C D D A N D V I A R E S I D U E S IN F O O D F R O M C U R R E N T S T U D Y
FOOD GROUP
DAILY CONSUMPTION (g/person/day) 1 w h o l e wt
Beef Pork Poultry Eggs Milk Products Fruit Vegetables Wheat Based Products 1 _ Nutrition
Canada,
55.8 19 20 29 444 190 220 125
1977;
2,3,7,8TCDD EquivalwDts (pg T E Q Z / q whole wt~
PCDF
DAILY
INTAKE Pg TEQ/kg pg TEQ~ body person ~ weight
0.29 0.03 0.39 0.59 0.ii 0.004 0.002 0.0007
16.2 0.6 7.8 17.0 48.8 0.76 0.44 0.09
0.27 0.01 0.13 0.28 0.81 0.06 0.007 0.001
Total:
91.7
1.52
2 _ TEQ
= toxic
equivalent;
3 = 60 k g
adult
The r e c o m m e n d e d m a x i m u m a l l o w a b l e d a i l y i n t a k e for P C D D a n d P C D F f r o m all e x p o s u r e s is the t o x i c e q u i v a l e n t of i0 p g of 2 , 3 , 7 , 8 - T C D D / k g b o d y w e i g h t (MOE, 1985; B i r m i n g h a m , et al, 1988; G i l m a n , et a l , 1988). In this t a b l e 4, we h a v e u s e d N u t r i t i o n C a n a d a (1977) c o n s u m p t i o n f a c t o r s . E s t i m a t e s of the r e l a t i v e t o x i c i t y of o t h e r P C D D a n d P C D F to 2 , 3 , 7 , 8 - T C D D ( t o x i c i t y e q u i v a l e n t s or TEQ) w e r e c a l c u l a t e d u s i n g the r e c e n t l y p r o p o s e d i n t e r n a t i o n a l s c h e m e of t o x i c i t y e q u i v a l e n c e f a c t o r s (TEF). (Boddington, 1987; N o r d i s k M i n i s t e r r a d , 1988). W h e r e d a t a w e r e r e p o r t e d as ND t h e n r e s i d u e s are a s s u m e d to be a b s e n t . D a i l y i n t a k e is e x p r e s s e d as p g assumedTEQ/pers°ntobe andl~%_TEQ/kg body weight. A b s o r p t i o n b y the G.I. t r a c t was
511
The
following points
can be made
- the foods which c o n t r i b u t e d followed by eggs and beef.
from Table 4:
the most exposure
to PCDD and PCDF were milk,
- the total c o n t r i b u t i o n from the animal products pg T E Q / k g body weight (about 99% of the total). - the plant products 1% of the total).
contribute
to the daily
0.02 pg of TEQ/kg body weight
intake
is 1.5
per day
(about
- the total c a l c u l a t e d daily intake of PCDD and PCDF from food is 1.52 pg TEQ/kg body weight or about 15% of the maximum allowable intake from all sources. Fish were not analysed in the present study. To estimate the added c o n t r i b u t i o n from fresh water fish to dietary intake, a reasonable estimate of 0.28 pg TEQ/kg body weight per day has been made (Birmingham et al, 1988). This would bring the daily exposure to 1.8 pg TEQ/kg bo y ~ g h t (about 18% of the m a x i m u m allowable daily exposure). When c a l c u l a t e d daily intake of TEQ via PCDD and PCDF residues in food is calculated using the assumption that ND data are present at the minimum reported detection limit, food intake (including freshwater fish) can account for 23% of the maximum allowable daily intake of PCDD and PCDF.) CONCLUSIONS 1.
2.
3. 4.
5.
These results indicate that the fruit and vegetable samples a n a l y s e d are s u b s t a n t i a l l y free of most PCDD and PCDF, e s p e c i a l l y the more toxic tetra-, penta- and hexa- c h l o r i n a t e d forms. This is a significant finding as the samples were not peeled. Except for the potato samples, the samples were not washed either. The skins of fruit and v e g e t a b l e s would be a n t i c i p a t e d to contain PCDD and PCDF if there was uptake due to exposure from airborne p a r t i c u l a t e s or soil. Generally, very low levels of 08CDD were found in egg, chicken, beef, hamburger, potato, apple, peaches and wheat samples. Some chicken and egg samples c o n t a i n e d higher PCDD and PCDF residues. The presence of higher c h l o r i n a t e d PCDD and PCDF in animal products reflects the higher fat content of these samples and the l i p o p h i l i c i t y of PCDD and PCDF. Residue levels in O n t a r i o - g r o w n plant and animal products were lower than or comparable to the levels found in imported food. Overall, the residue levels found in this study are s u b s t a n t i a l l y less than those found in the Davies and M a c P h e r s o n (1986) report. Other recently published Canadian, German and U.S. food monitoring studies (Firestone, et al, 1986; Ryan, et al, 1985a; Mathar, et al, 1987) also indicate t h a ' ~ - ~ and PCDF resl u---d-~ are g e n e r a l l y non----~ectable, similar to the results from the present study, except in special cases of known p e n t a c h l o r o p h e n o l c o n t a m i n a t i o n (Ryan, et al, 1984; Ryan, et al, 1985). ~r6-od intake (including fresh water fish) is the largest human exposure pathway for PCDD and PCDF, accounting for 95% of the total exposure, or up to 23% of the maximum allowable daily intake.
In conclusion, this study shows that exposure to PCDD and PCDF from c o n s u m p t i o n of c o m m e r c i a l l y available food in Ontario is well below the m a x i m u m allowable daily intake of I0 pg TEQ/kg body weight. BIBLIOGRAPHY Birmingham, B., A. Gilman, D. Grant, J. Salminen, M. Boddington, B. Thorpe, I. wile, P. Toft and V. Armstrong. 1988. P C D D / P C D F M u l t i m e d i a Exposure Analysis for the Canadian Population: D e t a i l e d Exposure Estimation. Dioxin'88, Umea, Sweden. Boddington, M. Considerations.
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512
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