POLYCHLORINATED PESTICIDES
BIPHENYLS,
AND CHLOROBENZENES
ORGANOCHLORINE CONTENT
OF L I V E R S
F R O M A T L A N T I C C O D (Gadus morhua) C A U G H T OFF H A L I F A X , NOVA SCOTIA H. C. F R E E M A N ,
J. F. U T H E
Fisheries and Environmental Sciences, Halifax Fisheries Research Laboratory, Department of Fisheries and Oceans, P.O. Box 550, Halifax, N. S. B3J 2S7 and P. J. S I L K
Research and Productivity Council, Chemistry Department, P.O. Box 6000, Fredericton, New Brunswick, E3B 5HI
(Received 23 June, 1983) Abstract. The mean levels + s.d., (ranges) of organochlorines, pesticides, chlorobenzenes and poly-
chlorinated biphenyl were determined in the livers of 100 Atlantic cod (Gadus morhua) caught off the east coast of Canada in 1980 and were as follows: PCB 1.71 _+0.90 (0.24--4.33); p,p'-DDE 0.28 + 0.15 (0.01-0.84); p , p ' - D D D 0.10 + 0.09 (trace-0.84); p,p'-DDT 0.15 +0.09 (ND-0.58); ~-HCH 0.06 + 0.02 (trace-0.10); ~-HCH (ND-trace); heptachlor 0.02 + 0.01 (ND-0.04); heptachlor epoxide 0.15 + 0.37 (ND-2.16); dieldrin 0.06 + 0.11 (ND-0.71); hexachlorobenzene 0.02 + 0.01 (trace-0.05) mg kg-l (wet wt.). The levels of these compounds in 1980 have not changed over the previous eight years with the exception of PCB and the DDT group where there appears to be a general decline between 1972 and 1975 with no significant change thereafter.
1. Introduction
In a earlier investigation it was found that polychlorinated biphenyl (PCB) concentrations in the livers of Atlantic cod (Gadusmorhua)caught off Halifax, N.S., Canada, ranged from 2 to 9 mg kg-l (wet wt.) (mean = 4.9 mg kg-l) [ 1]. Some of these fish had fatty degeneration of their livers similar to that which occured in Atlantic cod that had been fed low (p.p.m.) levels of PCB [1 ]. This created concern that marine organisms, the Atlantic cod in particular, could be accumulating pathogenic quantities of lipophilic organochlorine chemical compounds which are only slowly, if at all, subject to metabolic degradation. It was the purpose of the present study to determine current organochlorine levels in cod captured off Halifax.
Environmental Monitoring and Assessment 4 (1984) 389-394. 9 1984 by D. Reidel Publishing Company.
0167-6369/84/0044-0389500.60.
390
H. C. FREEMAN ET AL.
2. Methods and Materials 2.1. GLASSWARE All glassware was cleaned with fresh chromic acid, tap water, distilled water and finally rinsed with spectro-grade acetone followed by hexane. Glassware was then oven dried (105 ~ prior to use. 2.2. EXTRACTION APPARATUS An all-glass Soxhlet system was used; cellulose fiber thimbles were not used since they contained electron-capturing impurities that would interfere with the analysis. These were replaced with glass fiber filter papers and glass wool that were baked at 400 ~ overnight and then extracted with hexane prior to use. 2.3. MATERIALS B D H Chemicals (Merck) MO 7754-34 Fisher Scientific, A-540 Caledon, Spectro-grade Caledon, Spectro-Grade (no benzene detectable by UV) Diethyl Ether - Caledon, 'Distilled in Glass' Sodium sulphate - Anachemia, Anhydrous, AC-8515 Glass Fiber Filter Paper - Fisher Scientific, Grade 934 AH, 15 cm diameter The following treatments were applied to the precleaned selected materials: Silica Gel - washed with hexane/ether (10/90, v/v), air-dried, and heated at 130 ~ overnight. Each batch was then deactivated with 3 ~o distilled water (w/w) and allowed to equilibrate for 24 hr, after gentle shaking for 1 hr, prior to use. Alumina - heated at 800 ~C for 4 hr, deactivated with 5 ~/o distilled water (w/w), gently shaken for 1 hr and left to equilibrate overnight. Sodium Sulphate - prewashed in hexane and heated at 650 ~C for 6 hr prior to use. Silica gel, alumina and sodium batches, treated as above, were stored in a dessicator.
Silica Gel Alumina Acetone Hexane
-
2.4 INSTRUMENTATION The gas chromatographs used were a Varian 3700 or a Hewlett-Packard 5830A, each equipped with a Ni 63 electron capture detector. The columns used were 183 cm, 3 ~o SE-30 on Chromosorb W (80/100 mesh). The chromatographs were calibrated daily using external standardization. Chlorobenzenes were determined on a 20 m OV-17 SCOT capillary column (135~ ~ at 15 ~ min-l.) which resolved all congeners
POLYCHLOR1NATED BIPHENYLS, ORGANOCHLORINE PESTICIDES AND CHLOROBENZENES
391
except two of the three tetra-substituted compounds. Confirmations were performed on 10 ~o of the samples taken at random on a Finnigan 4021 EI/CI G C / M S with INCOS data system. 2.5. LIVER SAMPLES One hundred Atlantic cod (Gadus morhua) were caught alive by hand line a few miles south of Terrence Bay, Nova Scotia, Canada,on August 6 and 8, 1980. These fish were held alive in circulating sea water until landed at the Terrence Bay wharf where they were killed by a blow on the head. The livers were immediately excised, placed individually in a polyethylene plastic bag, and were frozen on dry ice and stored at -40 ~ until analyzed for contaminants. 2.6.
METHOD
OF EXTRACTION
AND CLEANUP
The method of extraction and analysis was essentially that of Zitko et al. [2] modified to allow the simultaneous determination of the chlorobenzenes along with polychlorinated biphenyl (PCB) and organochlorine pesticides. The liver from each fish was thawed and homogenized with a Polytron blender. A 5.0 g sample of the homogenate was removed for analysis and was ground with 20-25 g of anhydrous sodium sulphate to a free-flowing powder. The powder was then placed in a glass fiber filter paper (folded at the bottom) and Soxhlet extracted with hexane (300 ml) for one hr. The bulk of the solvent was removed by rotary evaporation to 80 ml and the extract was made up to 100 ml. A 10 ml aliquot was removed, the solvent evaporated under nitrogen, and the lipid content of this aliquot determined gravimetrically. A portion of the remaining solution equivalent to 50 mg of lipid was reduced to 1.5 ml under a stream of dry nitrogen, and applied to a glass column (60 x 0.7 cm) containing 2.0 g alumina. The column was then percolated with hexane and 20 ml eluant collected and evaporated to 1.5 ml which was then applied to a 2.0 g silica gel column with 1 ml of hexane. Effluent was collected in three fractions as follows: Fraction I. 4.0 ml hexane containing PCB, p,p'-DDE, chlorobenzenes, aldrin, heptachlor; Fraction II. 10.0 ml hexane containing heptachlor, aldrin, p,p'-DDT, heptachlor epoxide, p,p'-DDE, o , p ' - D D T ; Fraction III. 20.0 ml ofhexane: ether 10 ~o (10:90 v/v) containing heptachlor epoxide, lindane, ~-HCH, dieldrin, fl-endosulfan, p,p'-DDD. The elution characteristics of the silica gel columns were dependent on the activity of the specific batches of silica gel used and often the elution order of the above components slightly. This was taken into account by running standards through the entire procedure with each batch to establish elution order and recoveries. Recoveries of PCB (as Aroclor 1254"), organochlorine pesticides and chlorobenzenes from standards were generally around 90~o using the above techniques.
* Trade name - Monsanto Chemical Co., U.S.A.
392
H. C. FREEMAN ET AL.
Each fraction from each liver was evaporated to an appropriate volume (200/~1) and quantified by EC/GC. Results were calculated as mg kg-' of liver and were corrected for recoveries. The means and ranges of data of 100 fish livers analyzed individually and calculated on a wet weight basis are given in Table II; 10 ~o of the samples were analyzed in duplicate. Detection limits in fatty tissue, using the above techniques are as follows: PCB 0.01 mg kg-I lipid Organochlorines 0.01 mg kg-1 lipid Chlorobenzenes 0.01 mg k g -1 lipid 2.7.
ANALYTICAL QUALITY CONTROL STUDIES
As part of this study two herring oil samples that had been used in the International Council for Exploration of the Sea (ICES) intercomparative study for the determination of organochlorine compounds in fish oils [ 9] were analyzed to check the accuracy and precision of the methods. The analysts were unaware of the origin of these oils. The two oils were portions of the same herring oil, one of which was spiked with a known amount of Aroclor 1254. TABLE I A comparison of results obtained in the present study in the analysis of the ICES a intercomparative herring oil with the m e a n values reported by the ICES participants [9] (Reported as mg kg -L wet wt.). Compound
Present study
ICES participants
PCB (unspiked oil) PCB (spiked oil) hexachlorobenzene p,p'-DDE dieldrin p,p'-DDD p,p'-DDT :t-HCH
1.1, 1.0 2.0, 2.4 0.03, 0.04 0.27,0.27 0.08,0.08 0.07,0.07 ND, ND b ND, ND
1.09 1.93 0.035 0.22 0.06 0.08 0.15 0.02
+ 0.33 c + 0.41 +_ 0.015 + 0.06 + 0.04 + 0.08 + 0.14 + 0.02
a International Council for the Exploration of the Sea. b Could not be quantified at the time of analysis due to interferences. c Standard deviation (outliers excluded).
3. Results and Discussion
There was a good agreement in the results of the herring oil analyses in the present study and those in the ICES comparative study (Table I). p,p'-DDT reported as not detected, could not be quantified in the herring oil samples due to interferences at the time of analysis. However, the presence of p,p'-DDT in these samples was confirmed by GC/MS.
POLYCHLORINATED BIPHENYLS, ORGANOCHLORINE PESTICIDES AND CHLOROBENZENES
393
TABLE II Mean and range (mg kg-t wet wt.) ofchlorinated hydrocarbonsin 100cod livers (cod caught off Halifax, N.S., August, 1980) Compound
Mean a + s.d.
Range
PCB p,p'-DDE p,p'-DDD p,p'-DDT ~DDT ~-HCH ?-HCH heptachlor heptachlor epoxide
1.71 + 0.90 (100)c 0.28 + 0.15 (100) 0.10 + 0.09 ( 9 9 ) 0.15 + 0.09 ( 9 7 ) 0.53 0.06 + 0.02 ( 9 8 )
0.24-4.33 0.01-0.84 trace-0.84 NDb-0.58
dieldrin
0.06 + 0.11 ( 8 9 )
ND-0.71
hexachlorobenzened
0.02 _+0.01 ( 9 6 )
trace-0.05
0.02 + 0.01 (9) 0.15 + 0.37 ( 9 5 )
trace-0.10 trace, (96); ND, (4) ND-0.04 ND-2.16
a Not detectable and trace quantities were not includedin estimatingthe mean. b Not detectable. c Number of fish used in calculating mean. d Other chlorobenzene congeners were not detected.
The results are reported in Table II. Aldrin, fl-endosulfan and o , p ' - D D T were not detected in any of the samples; fl-endosulfan was not successfully eluted from the alumina cleanup step (low recoveries); its absence in any of the samples was inferred from the absence of the a-isomer which eluted quantitatively. During the G C / M S confirmations on random samples, mass peaks corresponding to cis and transchlordane which when present eluted quantitatively in fractions I and II could not be detected and therefore these compounds were deemed to be at undetectable levels in the samples. PCB was present in all samples and ranged from 0.24 to 4.33 mg/kg of liver with a mean (+ s.d.) of 1.71 + 0.90 mg kg-1 (Table II). The mean level of PCB in cod liver (Table II) is higher than the mean of 0.44 mg kg-1 in 2 fish from the same area in 1975 [ 3] but lower than the mean concentrations of 5.1 mg kg-1 (7 fish) reported in 1977 (4). The mean PCB concentration in cod livers (Table II) is lower than in cod livers from the Kattegat in 1975 [5] where PCB levels ranged from 4 to 53 mg kg-1 (mean 13 mg kg-~) and also much lower than in cod livers taken from Rio Fiord (Sweden) in 1975, where levels ranged from 29 to 57 mg kg-1 (mean 38 mg kg-1) [5]. Sims et al. [6] reported mean (range) organochlorine levels in livers from caught off the Atlantic coast of Canada in 1972/73 as follows: ~',DDT ( p , p ' - D D E + p , p ' - D D D + p , p ' - D D T ) 5.2 (0.50-23.3); hexachlorobenzene 0.039; dieldrin 0.035; and PCB 5.1 (0.89-19.3) mg kg-I. The mean levels (ranges) of organochlorine compounds found in cod livers in the same area in 1974/75 were: )-" D D T 1.46; dieldrin 0.064 (0.022-0.11); and PCB 2.05 (1.35-2.70) mg kg-~ [7].
394
H. C. F R E E M A N
E T AL.
A c o m p a r i s o n o f the a b o v e d a t a with our 1980 results (Table II) suggested that D D T levels have fallen from 1972/73 to 1974/75 with little change to 1980. The lack o f a p p r o p r i a t e statistical d a t a in the earlier p a p e r s m a k e s it impossible to analyze tha d a t a statistically. In the period 1972-80 it a p p e a r s that dieldrin levels have changed little. It a p p e a r s that the h e x a c h l o r o b e n z e n e levels m a y also be relatively static. A hexachlorob e n z e n e level o f 0.039 mg kg -1 was r e p o r t e d in a single sample of c o d liver in 1972/73 [6] c o m p a r e d to a m e a n level o f 0.02 mg kg -1 in this study. Results from a study o f c o n t a m i n a n t levels in c o d livers from the G u l f o f St. Lawrence, using length stratified fish and multiple linear regression techniques [8 ], however, suggested that hexachlorob e n z e n e levels were decreasing s o m e w h a t between 1977 and 1979. PCB levels (mean 5.1 mg k g - l) in c o d livers offthe Atlantic c o a s t o f C a n a d a in 1972/73 declined to a m e a n level o f 2.05 mg k g - i in 1974/75 [7] a n d a p p e a r e d to have changed little between 1974/75 and 1980 as indicated by a m e a n liver c o n c e n t r a t i o n o f 1.71 + 0.90 mg k g - 1 (Table II). In conclusion it a p p e a r s that m o s t organochlorine c o m p o u n d s in livers from c o d caught off the east c o a s t of C a n a d a in 1980 have n o t changed over the previous eight years with the exceptions o f PCB and the D D T group where there a p p e a r s to have been a general decline between 1972 a n d 1975 with no significant change thereafter.
References [1] Freeman, H. C. and Sangalang, G.: 1977, 'The Effects of a Polychlorinated Biphenyl (Aroclor 1254) Contaminated Diet on Steroidogenesis and Reproduction in the Atlantic Cod (Gadus morhua)', International Council for Exploration of the Sea C.M.1977/E:67. 12 pp. mimeo. [2] Zitko, V., Chou, P. M. K., Wildish, D. J., Monaghan, C. F., and Lister, N. A.: 1975, 'Distribution of PCB and pp'-DDE Residues in Atlantic Herring (Clupea harengus harengus) and Yellow Perch (Perca flavescens) in Eastern Canada, 1972', Pest. Monit. J. 8, 105-109. [3] International Council for Exploration of the Sea: 1976, 'Second Report of the Working Group on Pollution Baseline and Monitoring Studies in the Oslo Commission and ICNAF areas, Charlottenlund, Denmark, 10-13 May, 1976', C.M.1976/E:4. 93 pp. mimeo. [4] Freeman, H. C., Sangalang, G., and Flemming, B.: 1982, 'The Sublethal Effects of a Polychlorinated Biphenyl (Aroclor 1254) Diet on the Atlantic Cod (Gadus rnorhua)', Sci. Total. Environ. 24,1-11. [5] Falandysz, J.: 1981, 'Organochlorine Pesticides and PCB in Cod Liver Oil of Baltic Origin, 1971-80', Pestic. Monit..7. 15, 51-53. [6] Sims, G. G., Campbell, J. R., Zemlyak, F., and Graham, J. M.: 1977, 'Organochlorine Residues in Fish and Fish Products from the Northwest Atlantic, Bull. Environ. Contamin. Toxicol. 6, 697-705. [7] International Council for Exploration of the Sea: 1977, 'A Baseline Study of the Level of Contaminating Substances in Living Resources of the North Atlantic', I.C.E.S. Cooperative Research Report No. 69, 83 pp. [8] Scott, D. P., Uthe, J. F., and Chou, C. L.: 1981, 'Further Considerations of Time Trend Determinations of Contaminant Levels in Canadian Cod', International Council for the Exploration of the Sea, Copenhagen, Denmark. C.M. 1981/E:7. 15 pp. mimeo. [9] Uthe, J. F. and Musial, C. J.: 1982, 'Report on the Fourth ICES Intercalibration Study of PCBs in Biological Material', ICES. Coop. Res. Rep. No. 115. 53 pp.
BIPHENYLS,
AND CHLOROBENZENES
ORGANOCHLORINE CONTENT
OF L I V E R S
F R O M A T L A N T I C C O D (Gadus morhua) C A U G H T OFF H A L I F A X , NOVA SCOTIA H. C. F R E E M A N ,
J. F. U T H E
Fisheries and Environmental Sciences, Halifax Fisheries Research Laboratory, Department of Fisheries and Oceans, P.O. Box 550, Halifax, N. S. B3J 2S7 and P. J. S I L K
Research and Productivity Council, Chemistry Department, P.O. Box 6000, Fredericton, New Brunswick, E3B 5HI
(Received 23 June, 1983) Abstract. The mean levels + s.d., (ranges) of organochlorines, pesticides, chlorobenzenes and poly-
chlorinated biphenyl were determined in the livers of 100 Atlantic cod (Gadus morhua) caught off the east coast of Canada in 1980 and were as follows: PCB 1.71 _+0.90 (0.24--4.33); p,p'-DDE 0.28 + 0.15 (0.01-0.84); p , p ' - D D D 0.10 + 0.09 (trace-0.84); p,p'-DDT 0.15 +0.09 (ND-0.58); ~-HCH 0.06 + 0.02 (trace-0.10); ~-HCH (ND-trace); heptachlor 0.02 + 0.01 (ND-0.04); heptachlor epoxide 0.15 + 0.37 (ND-2.16); dieldrin 0.06 + 0.11 (ND-0.71); hexachlorobenzene 0.02 + 0.01 (trace-0.05) mg kg-l (wet wt.). The levels of these compounds in 1980 have not changed over the previous eight years with the exception of PCB and the DDT group where there appears to be a general decline between 1972 and 1975 with no significant change thereafter.
1. Introduction
In a earlier investigation it was found that polychlorinated biphenyl (PCB) concentrations in the livers of Atlantic cod (Gadusmorhua)caught off Halifax, N.S., Canada, ranged from 2 to 9 mg kg-l (wet wt.) (mean = 4.9 mg kg-l) [ 1]. Some of these fish had fatty degeneration of their livers similar to that which occured in Atlantic cod that had been fed low (p.p.m.) levels of PCB [1 ]. This created concern that marine organisms, the Atlantic cod in particular, could be accumulating pathogenic quantities of lipophilic organochlorine chemical compounds which are only slowly, if at all, subject to metabolic degradation. It was the purpose of the present study to determine current organochlorine levels in cod captured off Halifax.
Environmental Monitoring and Assessment 4 (1984) 389-394. 9 1984 by D. Reidel Publishing Company.
0167-6369/84/0044-0389500.60.
390
H. C. FREEMAN ET AL.
2. Methods and Materials 2.1. GLASSWARE All glassware was cleaned with fresh chromic acid, tap water, distilled water and finally rinsed with spectro-grade acetone followed by hexane. Glassware was then oven dried (105 ~ prior to use. 2.2. EXTRACTION APPARATUS An all-glass Soxhlet system was used; cellulose fiber thimbles were not used since they contained electron-capturing impurities that would interfere with the analysis. These were replaced with glass fiber filter papers and glass wool that were baked at 400 ~ overnight and then extracted with hexane prior to use. 2.3. MATERIALS B D H Chemicals (Merck) MO 7754-34 Fisher Scientific, A-540 Caledon, Spectro-grade Caledon, Spectro-Grade (no benzene detectable by UV) Diethyl Ether - Caledon, 'Distilled in Glass' Sodium sulphate - Anachemia, Anhydrous, AC-8515 Glass Fiber Filter Paper - Fisher Scientific, Grade 934 AH, 15 cm diameter The following treatments were applied to the precleaned selected materials: Silica Gel - washed with hexane/ether (10/90, v/v), air-dried, and heated at 130 ~ overnight. Each batch was then deactivated with 3 ~o distilled water (w/w) and allowed to equilibrate for 24 hr, after gentle shaking for 1 hr, prior to use. Alumina - heated at 800 ~C for 4 hr, deactivated with 5 ~/o distilled water (w/w), gently shaken for 1 hr and left to equilibrate overnight. Sodium Sulphate - prewashed in hexane and heated at 650 ~C for 6 hr prior to use. Silica gel, alumina and sodium batches, treated as above, were stored in a dessicator.
Silica Gel Alumina Acetone Hexane
-
2.4 INSTRUMENTATION The gas chromatographs used were a Varian 3700 or a Hewlett-Packard 5830A, each equipped with a Ni 63 electron capture detector. The columns used were 183 cm, 3 ~o SE-30 on Chromosorb W (80/100 mesh). The chromatographs were calibrated daily using external standardization. Chlorobenzenes were determined on a 20 m OV-17 SCOT capillary column (135~ ~ at 15 ~ min-l.) which resolved all congeners
POLYCHLOR1NATED BIPHENYLS, ORGANOCHLORINE PESTICIDES AND CHLOROBENZENES
391
except two of the three tetra-substituted compounds. Confirmations were performed on 10 ~o of the samples taken at random on a Finnigan 4021 EI/CI G C / M S with INCOS data system. 2.5. LIVER SAMPLES One hundred Atlantic cod (Gadus morhua) were caught alive by hand line a few miles south of Terrence Bay, Nova Scotia, Canada,on August 6 and 8, 1980. These fish were held alive in circulating sea water until landed at the Terrence Bay wharf where they were killed by a blow on the head. The livers were immediately excised, placed individually in a polyethylene plastic bag, and were frozen on dry ice and stored at -40 ~ until analyzed for contaminants. 2.6.
METHOD
OF EXTRACTION
AND CLEANUP
The method of extraction and analysis was essentially that of Zitko et al. [2] modified to allow the simultaneous determination of the chlorobenzenes along with polychlorinated biphenyl (PCB) and organochlorine pesticides. The liver from each fish was thawed and homogenized with a Polytron blender. A 5.0 g sample of the homogenate was removed for analysis and was ground with 20-25 g of anhydrous sodium sulphate to a free-flowing powder. The powder was then placed in a glass fiber filter paper (folded at the bottom) and Soxhlet extracted with hexane (300 ml) for one hr. The bulk of the solvent was removed by rotary evaporation to 80 ml and the extract was made up to 100 ml. A 10 ml aliquot was removed, the solvent evaporated under nitrogen, and the lipid content of this aliquot determined gravimetrically. A portion of the remaining solution equivalent to 50 mg of lipid was reduced to 1.5 ml under a stream of dry nitrogen, and applied to a glass column (60 x 0.7 cm) containing 2.0 g alumina. The column was then percolated with hexane and 20 ml eluant collected and evaporated to 1.5 ml which was then applied to a 2.0 g silica gel column with 1 ml of hexane. Effluent was collected in three fractions as follows: Fraction I. 4.0 ml hexane containing PCB, p,p'-DDE, chlorobenzenes, aldrin, heptachlor; Fraction II. 10.0 ml hexane containing heptachlor, aldrin, p,p'-DDT, heptachlor epoxide, p,p'-DDE, o , p ' - D D T ; Fraction III. 20.0 ml ofhexane: ether 10 ~o (10:90 v/v) containing heptachlor epoxide, lindane, ~-HCH, dieldrin, fl-endosulfan, p,p'-DDD. The elution characteristics of the silica gel columns were dependent on the activity of the specific batches of silica gel used and often the elution order of the above components slightly. This was taken into account by running standards through the entire procedure with each batch to establish elution order and recoveries. Recoveries of PCB (as Aroclor 1254"), organochlorine pesticides and chlorobenzenes from standards were generally around 90~o using the above techniques.
* Trade name - Monsanto Chemical Co., U.S.A.
392
H. C. FREEMAN ET AL.
Each fraction from each liver was evaporated to an appropriate volume (200/~1) and quantified by EC/GC. Results were calculated as mg kg-' of liver and were corrected for recoveries. The means and ranges of data of 100 fish livers analyzed individually and calculated on a wet weight basis are given in Table II; 10 ~o of the samples were analyzed in duplicate. Detection limits in fatty tissue, using the above techniques are as follows: PCB 0.01 mg kg-I lipid Organochlorines 0.01 mg kg-1 lipid Chlorobenzenes 0.01 mg k g -1 lipid 2.7.
ANALYTICAL QUALITY CONTROL STUDIES
As part of this study two herring oil samples that had been used in the International Council for Exploration of the Sea (ICES) intercomparative study for the determination of organochlorine compounds in fish oils [ 9] were analyzed to check the accuracy and precision of the methods. The analysts were unaware of the origin of these oils. The two oils were portions of the same herring oil, one of which was spiked with a known amount of Aroclor 1254. TABLE I A comparison of results obtained in the present study in the analysis of the ICES a intercomparative herring oil with the m e a n values reported by the ICES participants [9] (Reported as mg kg -L wet wt.). Compound
Present study
ICES participants
PCB (unspiked oil) PCB (spiked oil) hexachlorobenzene p,p'-DDE dieldrin p,p'-DDD p,p'-DDT :t-HCH
1.1, 1.0 2.0, 2.4 0.03, 0.04 0.27,0.27 0.08,0.08 0.07,0.07 ND, ND b ND, ND
1.09 1.93 0.035 0.22 0.06 0.08 0.15 0.02
+ 0.33 c + 0.41 +_ 0.015 + 0.06 + 0.04 + 0.08 + 0.14 + 0.02
a International Council for the Exploration of the Sea. b Could not be quantified at the time of analysis due to interferences. c Standard deviation (outliers excluded).
3. Results and Discussion
There was a good agreement in the results of the herring oil analyses in the present study and those in the ICES comparative study (Table I). p,p'-DDT reported as not detected, could not be quantified in the herring oil samples due to interferences at the time of analysis. However, the presence of p,p'-DDT in these samples was confirmed by GC/MS.
POLYCHLORINATED BIPHENYLS, ORGANOCHLORINE PESTICIDES AND CHLOROBENZENES
393
TABLE II Mean and range (mg kg-t wet wt.) ofchlorinated hydrocarbonsin 100cod livers (cod caught off Halifax, N.S., August, 1980) Compound
Mean a + s.d.
Range
PCB p,p'-DDE p,p'-DDD p,p'-DDT ~DDT ~-HCH ?-HCH heptachlor heptachlor epoxide
1.71 + 0.90 (100)c 0.28 + 0.15 (100) 0.10 + 0.09 ( 9 9 ) 0.15 + 0.09 ( 9 7 ) 0.53 0.06 + 0.02 ( 9 8 )
0.24-4.33 0.01-0.84 trace-0.84 NDb-0.58
dieldrin
0.06 + 0.11 ( 8 9 )
ND-0.71
hexachlorobenzened
0.02 _+0.01 ( 9 6 )
trace-0.05
0.02 + 0.01 (9) 0.15 + 0.37 ( 9 5 )
trace-0.10 trace, (96); ND, (4) ND-0.04 ND-2.16
a Not detectable and trace quantities were not includedin estimatingthe mean. b Not detectable. c Number of fish used in calculating mean. d Other chlorobenzene congeners were not detected.
The results are reported in Table II. Aldrin, fl-endosulfan and o , p ' - D D T were not detected in any of the samples; fl-endosulfan was not successfully eluted from the alumina cleanup step (low recoveries); its absence in any of the samples was inferred from the absence of the a-isomer which eluted quantitatively. During the G C / M S confirmations on random samples, mass peaks corresponding to cis and transchlordane which when present eluted quantitatively in fractions I and II could not be detected and therefore these compounds were deemed to be at undetectable levels in the samples. PCB was present in all samples and ranged from 0.24 to 4.33 mg/kg of liver with a mean (+ s.d.) of 1.71 + 0.90 mg kg-1 (Table II). The mean level of PCB in cod liver (Table II) is higher than the mean of 0.44 mg kg-1 in 2 fish from the same area in 1975 [ 3] but lower than the mean concentrations of 5.1 mg kg-1 (7 fish) reported in 1977 (4). The mean PCB concentration in cod livers (Table II) is lower than in cod livers from the Kattegat in 1975 [5] where PCB levels ranged from 4 to 53 mg kg-1 (mean 13 mg kg-~) and also much lower than in cod livers taken from Rio Fiord (Sweden) in 1975, where levels ranged from 29 to 57 mg kg-1 (mean 38 mg kg-1) [5]. Sims et al. [6] reported mean (range) organochlorine levels in livers from caught off the Atlantic coast of Canada in 1972/73 as follows: ~',DDT ( p , p ' - D D E + p , p ' - D D D + p , p ' - D D T ) 5.2 (0.50-23.3); hexachlorobenzene 0.039; dieldrin 0.035; and PCB 5.1 (0.89-19.3) mg kg-I. The mean levels (ranges) of organochlorine compounds found in cod livers in the same area in 1974/75 were: )-" D D T 1.46; dieldrin 0.064 (0.022-0.11); and PCB 2.05 (1.35-2.70) mg kg-~ [7].
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A c o m p a r i s o n o f the a b o v e d a t a with our 1980 results (Table II) suggested that D D T levels have fallen from 1972/73 to 1974/75 with little change to 1980. The lack o f a p p r o p r i a t e statistical d a t a in the earlier p a p e r s m a k e s it impossible to analyze tha d a t a statistically. In the period 1972-80 it a p p e a r s that dieldrin levels have changed little. It a p p e a r s that the h e x a c h l o r o b e n z e n e levels m a y also be relatively static. A hexachlorob e n z e n e level o f 0.039 mg kg -1 was r e p o r t e d in a single sample of c o d liver in 1972/73 [6] c o m p a r e d to a m e a n level o f 0.02 mg kg -1 in this study. Results from a study o f c o n t a m i n a n t levels in c o d livers from the G u l f o f St. Lawrence, using length stratified fish and multiple linear regression techniques [8 ], however, suggested that hexachlorob e n z e n e levels were decreasing s o m e w h a t between 1977 and 1979. PCB levels (mean 5.1 mg k g - l) in c o d livers offthe Atlantic c o a s t o f C a n a d a in 1972/73 declined to a m e a n level o f 2.05 mg k g - i in 1974/75 [7] a n d a p p e a r e d to have changed little between 1974/75 and 1980 as indicated by a m e a n liver c o n c e n t r a t i o n o f 1.71 + 0.90 mg k g - 1 (Table II). In conclusion it a p p e a r s that m o s t organochlorine c o m p o u n d s in livers from c o d caught off the east c o a s t of C a n a d a in 1980 have n o t changed over the previous eight years with the exceptions o f PCB and the D D T group where there a p p e a r s to have been a general decline between 1972 a n d 1975 with no significant change thereafter.
References [1] Freeman, H. C. and Sangalang, G.: 1977, 'The Effects of a Polychlorinated Biphenyl (Aroclor 1254) Contaminated Diet on Steroidogenesis and Reproduction in the Atlantic Cod (Gadus morhua)', International Council for Exploration of the Sea C.M.1977/E:67. 12 pp. mimeo. [2] Zitko, V., Chou, P. M. K., Wildish, D. J., Monaghan, C. F., and Lister, N. A.: 1975, 'Distribution of PCB and pp'-DDE Residues in Atlantic Herring (Clupea harengus harengus) and Yellow Perch (Perca flavescens) in Eastern Canada, 1972', Pest. Monit. J. 8, 105-109. [3] International Council for Exploration of the Sea: 1976, 'Second Report of the Working Group on Pollution Baseline and Monitoring Studies in the Oslo Commission and ICNAF areas, Charlottenlund, Denmark, 10-13 May, 1976', C.M.1976/E:4. 93 pp. mimeo. [4] Freeman, H. C., Sangalang, G., and Flemming, B.: 1982, 'The Sublethal Effects of a Polychlorinated Biphenyl (Aroclor 1254) Diet on the Atlantic Cod (Gadus rnorhua)', Sci. Total. Environ. 24,1-11. [5] Falandysz, J.: 1981, 'Organochlorine Pesticides and PCB in Cod Liver Oil of Baltic Origin, 1971-80', Pestic. Monit..7. 15, 51-53. [6] Sims, G. G., Campbell, J. R., Zemlyak, F., and Graham, J. M.: 1977, 'Organochlorine Residues in Fish and Fish Products from the Northwest Atlantic, Bull. Environ. Contamin. Toxicol. 6, 697-705. [7] International Council for Exploration of the Sea: 1977, 'A Baseline Study of the Level of Contaminating Substances in Living Resources of the North Atlantic', I.C.E.S. Cooperative Research Report No. 69, 83 pp. [8] Scott, D. P., Uthe, J. F., and Chou, C. L.: 1981, 'Further Considerations of Time Trend Determinations of Contaminant Levels in Canadian Cod', International Council for the Exploration of the Sea, Copenhagen, Denmark. C.M. 1981/E:7. 15 pp. mimeo. [9] Uthe, J. F. and Musial, C. J.: 1982, 'Report on the Fourth ICES Intercalibration Study of PCBs in Biological Material', ICES. Coop. Res. Rep. No. 115. 53 pp.
