Environ. Sci. Technol. 1983, 17, 287-291
Bioconcentration of Chlorobenzenes from Water by Rainbow Trout: Correlations with Partition Coefficients and Environmental Residues Barry G. Oliver*+ and Arthur J. Nilmi*
Environmental Contaminants Division, National Water Research Institute and Great Lakes Biolimnology Laboratory, Canada Centre for Inland Waters, Burlington, Ontario, Canada L7R 4A6 The bioconcentration by rainbown trout of ten chlorobenzenes (CB's), hexachlorobutadiene (HCBD), and hexachloroethane (HCE) at water concentrations near environmental levels (nanograms per liter range) has been studied. The bioconcentration factor (BCF) for the CBs was found to increase dramatically as the degree of chlorine substitution on the aromatic ring became greater. There was a high correlation between the BCF and the octanol-water partition coefficient for HCBD, HCE, and all the chlorobenzenes except hexachlorobenzene (HCB). Ten adult rainbow trout from Lake Ontario were analyzed for these contaminants. Then, with use of field values for contaminant concentrations in water and laboratory values for BCF's, predictions of field concentrations in fish (on the basis of accumulation from water only) were made. These values were then compared to the fish field data.
Introduction Environmental contaminants can be accumulated by fish through direct uptake from water and through food intake. The primary mode of accumulation in most cases is dependent on the concentration of the substance in the water and food and the trophic position of the species. It has been suggested that the food pathway is the most important for carnivorous species that occupy the higher trophic levels for the more persistent organic contaminants such as DDT and hexachlorobenzene when concentrations in the natural environment are taken into consideration (I, 2). Other chemicals can be accumulated from water by fish (3). For example, pentachlorophenol is a chemical with relatively high water solubility compared to many other chlorinated hydrocarbons and is accumulated from water by fish even at concentrations in the low nanograms per liter range (4). The bioconcentration factor, BCF, which is the chemical concentration in the fish divided by the chemical concentration in the water, has been used to estimate the propensity of a chemical to bioaccumulate in fish (5). The BCF has been shown to be highly correlated to the octanol-water partition coefficient for a wide variety of chemicals (5-9). It has been suggested that the lower the water solubility of a chemical the more readily it will partition into the fish lipid (10). This relationship has been demonstrated in fish primarily in laboratory studies. The chlorobenzenes (CB's) represent a family of compounds reported to be present in the aquatic environment that have differing physical and chemical properties, which includes a wide range of octanol-water partition coefficients (11-14). Chlorobenzenes have been shown to occur in Great Lakes fishes (15),and concentrations in the water and effluents have recently been reported to be in the nanograms per liter range (16). In order to examine the environmental impact and bioconcentration properties of this group of substances, subadult rainbow trout (Salmo gairdneri) were exposed to a mixture of di- through hexachlorobenzene in water. This study was designed to de'National Water Research Institute. Great Lake Biolimnology Laboratory.
*
0013-936X/83/0917-0287$01.50/0
termine if the bioconcentration factor in fish exposed over an extended time period was dependent on the concentration particularly when exposure levels were ambient or only slightly higher than those reported in the natural environment. In addition, hexachlorobutadiene and hexachloroethane were also studied to determine if significant differences in behavior occurred between these aliphatic chlorinated substances and the aromatic chlorobenzenes. The results of these laboratory studies were than compared with the levels of these substances that were monitored in adult rainbow trout collected from Lake Ontario.
Experimental Section Thirty-two hatchery-reared rainbow trout, each averaging 250 g initially, were maintained in two 1 X 1X 0.5 m self-cleaning fiberglass tanks and 26 fish in a third tank for 1month before exposure. All tanks were provided with a 6 L/min flow of water held at 15 f 1"C according to the experimental conditions described previous (2). The water was drawn from Lake Ontario for domestic purposes and was passed through an activated charcoal filter. The fish were fed approximately 2% of body weight each day on a dry commercial diet. An aqueous CB mixture was continuously pumped into the low- and high-exposure tanks and distilled water into the control tank, at a rate of 1 mL/min by using a multichannel peristaltic pump. The CB mixture was prepared by adding 5 and 50 mL of the stock solution containing the standards dissolved in methanol to 4 L of water. Then 45 and 50 mL of methanol were added to the low and control containers, respectively, so each of the three solutions contained 50 mL of methanol. The solutions were replaced every 2 days. The action of the external pump was used to create an 8-12 cm/s current, and the swimming response of the fish facilitated good mixing in the tanks. The tanks were sampled and analyzed weekly. The concentrations used ranged from 0.1-47 ng/L in the lowexposure tank to 3-940 ng/L in the high-exposure tank depending on the chemical. These levels were based on the environmental concentrations in Lake Ontario (16). The chemicals in this study, 1,2-dichlorobenzene (1,2DCB), 1,3-dichlorobenzene(1,3-DCB),l,4-dichlorobenzene (1,4-DCB), 1,3,5-trichlorobenzene (1,3,5-TCB), 1,2,4-trichlorobenzene (1,2,4-TCB), 1,2,3-trichlorobenzene (1,2,3-TCB), 1,2,4,5-tetrachlorobenzene(1,2,4,5-TeCB), 1,2,3,4-tetrachlorobenzene(1,2,3,4-TeCB), pentachlorobenzene (QCB), hexachlorobenzene (HCB), 1,1,2,3,4,4hexachloro-1,3-butadiene(HCBD), and hexachloroethane (HCE), were used as received from Aldrich Chemical Co. Two fish were removed from each tank at the start of the exposure period. Subsequent samples of six fish each were taken after 10,34,63, and 119 days from the control tank, after 8,39,69,99, and 119 days from the low-exposure tank, and after 7,22,43, 63, and 105 days from the high-exposure tank. All fish were wrapped in aluminum foil and frozen until analysis. No mortalities were incurred during the study period, except one fish from the control tank was accidently lost through the outflow near the end of the study.
0 1983 American Chemlcai Society
Environ. Sci. Technol., Vol. 17,No. 5, 1983 287
Table I. Relationship between Exposure Levels of 1 2 Waterborne Chemicals and Residue Levels in Rainbow Troutu fish wt, g fish food, ng/g control water, ng/L fish, ng/g day 0 day 10 day 34 day 6 3 day 119 low exposure water, ng/L fish, ng/g day 8
lipid, 5%
9 t 6 255 ?: 273 f 283 f 365 t 419 f
184 7.1 i 29 8.6 + 76 9.5 t 49 11.2 t 1 0 1 10.5 f
0.7 1.2 1.5 2.1 1.5
NDe 2.5 f 3.2 + 5.9 t 2.9 + 47
242
4+2
0.3 + 0.1
0.5 + 0.2
ND 1.9 i 0.2 6.7 + 0.7 2.1 f 0.7 ND
ND 2.1 * 0.3 2.8 + 1.0 1.9 f 0.5 ND
ND 0.6 + 1.1f 1.0 f 0.2 f
0.22 t 0.06 0.9 f 0.9 4.7 f 0.7 1.8 i 0.4 0.3 f 0.1
28+ 5
28i 5
0.1 0.3 0.2 0.1
2.3 i 0.4
3.2 i 2
6 7 0 i 180
390 t 66 (500) 1.3 360 + 67 (400) 2.9 630 i 190 (680) 1.3 4 7 0 r 100 (500) 1.2 6 7 0 t 99 (710) 5 6 0 i 130
3 6 0 t 57 (660) 330 f 6 3 (550) 6 0 0 t 190 (910) 4 3 0 r 98 (650) 640i. 100 (920) 7 4 0 2 170
3 4 0 t 56 (680) 3 0 0 t 56 (610) 5 4 0 t 170 (910) 390 + 9 1 (620) 5 4 0 f 97 (800) 7 2 0 f 130
day 69
285
t
62
8.7 + 2.5
day 99
334
f
100
8.3 t 3.3
day 119
349
i
67
8.2 f 1.9
BCF (mean i SD) high exposure water, ng/L fish, ng/g 279 day 7
i
31
7.2 f 1.5
day 22
290
f
17
8.0 f
day 43
277
i.
58
9.4 t
day 63
364 2 78
10.7 t
day 105
400
t
4+2
6 9 0 + 150
8.4 t 0.8
8.7
1.1
9 4 0 r 160
291 f 55
130
1,2,4-TCB
4.0 t 0.8 3.7 r 0.7 1 2 f 2.0 (1400) 8.6 (1100) t 1.7 (340) 14 i 3.0 4.6 f 1.0 (1800) (1900) (490) 11f 4.8 4.4 + 1.3 4.6 f 1.5 (1900) (1200) (390) 7.9 f 1.9 3.9 i 0.9 3.7 f 0.8 (1700) (1100) (300) 9.9 f 3.0 4.5 f 0.7 4.4 i. 0.8 (2000) (1300) (360) 370 + 7 3 1 8 0 0 f 240 1 3 0 0 t 320
day 39
t
17
chemical 1,4-DCB 1,3,5-TCB 2.1 ND
1 4 t 2.3 (370) 11 f 3.6 (380) 1 2 f 4.2 (430) 1 2 f 3.4 (420) 1 3 f 2.2 (480) 420i. 43
8.1 t 1.7
f
f
0.2 0.5 1.2 1.5
1,3-DCB 2.6
14 + 2.3 (260) 11 f 2.3 (250) 12 f 3.8 (250) 1 2 f 2.9 (270) 1 4 f 1.8 (300) 2 7 0 t 21
27
BCF (mean * SD)
1,2-DCB 2.2
45
f
20
81 t 1 0 (3700) 9 3 t 15 (3800) 200f 61 (5100) 1 3 0 f 32 (8400) 200i. 28 (4400) 4100 f 690
5 2 + 21 8 2 t 10 (2900) 88 f 1 5 (3000) 1 9 0 t 54 (4000) 1 2 0 t 28 (2700) 180 f 23 (3400) 3200 f 540
Values shown at each sample interval represent the mean + standard deviation of six fish. Values shown beneath in parentheses represent the bioconcentration factor (BCF) for each sample interval. Mean of last four samples. Mean of
Adult rainbow trout were also collected during their spawning migration in the Ganaraska River, a tributary of Lake Ontario. These fish averaged 3100 g, and ranged from 1520 to 4670 g. All fish were prepared for chemical analysis according to the following procedure. Following thawing, the contents of the digestive tract were removed, and then the fish were weighed. The whole fish was then ground to a homogeneous composition by using a Hobart grinder and then an Oster blender (17). The homogenates were refrozen until solvent extraction. The analytical procedure for water and fish using capillary gas chromatography and electron capture detectors have been previously described (18, 19). Briefly, water samples (4 L) were extracted with 75 mL of pentane, and the extract was concentrated to 1 mL and then cleaned up with a NazS04/Florisil column prior to analysis (18). The homogenate samples of fish (15 g) were ground with Na2S04and then Soxhlet extracted with acetone/hexane for 24 h. The acetone was removed by shaking with water, and the hexane was evaporated to =30 mL by using a three-stage Snyder condenser. Following cleanup of this hexane extract using a large NazS04/alumina/silica gel/ Florisil column, the samples were reconcentrated (to 1mL for the control and low-exposure samples and to 10 mL for the high-exposure samples) and polished on a small column of 40% HzS04on silica gel (19). The reproducibility of these techniques on replicate samples was &lo%. Recovery efficiencies for CB’s, HCE, and HCBD from fish and water in the concentration range of the study varied 288
Environ. Sci. Technol., Vol. 17, No. 5, 1983
between 80% and 92% (depending on compound) and were not concentration dependent. All reported data are corrected for recovery efficiency. Lipid content was determined by extracting a 1-2-g sample with a chloroform:methanol mixture (20).
Results and Discussion (a) Laboratory Studies on Bioconcentration. All 12 compounds under study were tested at one time, because our capillary chromotographic analysis procedure permitted us to separate and quantitate all of these components. Also, earlier studies by Veith et al. (5) showed no differences in BCF’s when compounds were tested individually or in mixtures. Residue concentrations of the chemical examined remained relatively constant over the 119-day period in the control fish (Table I), This accumulation was probably obtained from the food and from chemicals which may have been carried over from the other tanks, which were in close proximity. Fish at the high-exposure level may have attained equilibrium concentrations faster than those exposed at the lower level. Concentrations of 11of the 12 chemicals at the high-exposure level attained equilibrium within the first sample interval (7 days). The exception was HCB, which did not attain equilibrium even after the final sample (105 days). Fish exposed to HCE and the diand trichlorobenzenes at the low-exposure level attained equilibrium by the first sample interval (8 days), while 1,2,4,5-TeCB required at least 39 days and 1,2,3,4-TeCB,
1,2,3-TCB ND
1,2,4,5-TeCB ND
1,2,3,4-TeCB 0.4
HCB
0.6 0.1 It: 0.1
4.2
HCBD 0.08
HCE 0.04
0.1 f 0.1
0.03 ?r 0.01
0.03 i: 0.01
0.09 f 0.05 0.15 f 0.06 0.2 i 0.05 0.1 f 0.02 0.08 t 0.02
0.06 t 0.13 f 0.06 f 0.03 f 0.06 f
0.04 0.07 0.01 0.01 0.04
0.32
0.08
0.3
0.2
f
0.2
0.3
0.2 0.4 0.4 0.04
0.7 i 1.1f 1.6 i 1.6 ?: 0.6 +
0.7 0.4 0.4 0.4 0.3
0.23 f 0.7 0.9 f 0.2 1.8 i 0.4 2.3 f 0.5 1.0 f 0.4
0.46 f 0.18 0.6 t 0.1 1.5 f 0.2 1 . 3 f 0.3 0.9 t 0.4
2.3 f 2.9 f 3.4 f ’ 3.1 f 2.7 f
1.0 t 0.5
1.4 i. 0.3
0.34
0.1
0.32 f 0.3
0.10 + 0.02
4.8 r 0.8 (1100) 6.6 f 1.4 (1600) 5.3 * 1.6 (1100) 4.4 f 1.0 (1000) 5.3 t 0.8 (1300) 1200 f 250
2.6 f 0.5 (2300) 4.9 t 0.8 (5400) 5.7 1.5 (4900) 5.5 f 1.3 (4800) 6.9 f 1.0 (62002 5300 t 640
2.8 f 0.6 (2300) 5.5 f 0.8 (4000) 7.7 f 2.0 (5600) 6.2 f 1.4 (4600) 7.6 f 1.0 (5300) 5200 * 5OOc
1.2 f 0.2 (2900) 3.0 f 0.3 (8300) 4.1 f 0.7 (12 000) 4.2 ir 0.9 (11000) 5.2 f 0.5 (14 000) 1 3 0 0 0 f 13OOc
2.9 f 0.4 (2400) 3.8 ~t 0.6 (5800) 4.5 f 0.8 (11000) 4.5 f 0.9 (7800) 6.0 f 0.5 (12 000) 12000d
0.37 i 0.09 (2000) 0.56 i. 0.08 (4200) 0.59 f 0.19 (5500) 0.57 f 0.17 (5100) 0.76 f 0.14 (6700) 5800 f 84OC
7 2 f 25
2 1 t 13
9.7
f
ND 0.9 f 2.2 f 1.8 f 0.1 f
4.3 f 2
9 6 f 12 (2500) l o o + 17 (2300) 210f 61 (3300) 1 4 0 f 32 (2200) 210i 32 (2900) 2600 i 460
26
?:
f
0.2
chemical QCB
15
76 i 5.8 79t 6 (12 000) (11000) l l 0 c 20 1 2 0 i 18 ( 1 3 000) (11 0 0 0 ) 350 t 92 2 9 0 i 75 (15 000) (14 000) 240 t 66 200 f 49 (11000) (10 000) 320 t 40 3 2 0 t 39 (15 000) (13 000) 1 3 0 0 0 t 1700 1 2 0 0 0 ?: 1500
last three samples.
9.3
f
f
8.0
7.6
34t 2 (19 000) 61 f 6 (180 0 0 ) 2 1 0 t 36 (19 000) 1 6 0 f 38 (18 000) 220 i 25 ( 2 3 000) 20000 c 2100
f
0.2 0.8 0.2 0.6 0.9
1 3 f 0.8 (7500) 24 f 2.7 (9500) 9 5 f 10 (12 000) 8 8 i 16 (14 000) 160 f 29 (20 000)
Last sample; this compound does not appear to be equilibrated.
QCB, and HCBD at least 69 days (Table I). HCB did not attain equilibrium after 119 days a t the low level of exposure. The bioconcentration factors in fish at each sample interval at both exposure levels were estimated after subtracting the mean residue levels of the control fish. All chemicals except HCB attained equilibrium at the low- and high-exposure level during the study period (Table I). It was evident that the higher the degree of chlorination on the aromatic ring, the longer it required for the systems to equilibrate and the higher the BCF factor (Figure 1). The BCF a t the high-exposure level averaged 2.2 times higher than that at the low-exposure levels for all chemicals. A similar concentration-dependent relationship was suggested for the uptake of brominated toluenes by salmon although the fish may not have attained equilibrium (21). This difference in BCF’s probably indicates that the rates of detoxification and elimination of these chemicals by the fish are concentration dependent. Total chemical accumulations in the fish tissue were 3 ppm at the “high” dose and only 0.07 ppm a t the “low” dose. Lipid contents of the individual fish were measured. When BCF’s were recalculated assuming chemicals partitioned into the lipids, no significant reduction in BCF standard deviations was observed. This indicates that the variability in BCF’s is probably not due to differing lipid contents of the fish. The largest contribution to BCF scatter appears to be variability in individual fish uptake and elimination rates, with smaller contributions coming
7.1 ?: 2.1
1 4 t 0.8 21(16 i 2.9 000)
3.7 c 2.3 (790) 5.8 f 3.0 (790) 1 2 t 6.6 (1900) 6.2 f 2.6 (960) 7.1 f 2.1 (990) 1 2 0 0 i 450
i.
(17 000) 6 1 f 15 (19 000) 4 5 r 12 (16 000) 6 3 f 10 (19 000) 17 000 f 1400
20 oooc
e
0.26 f 0.06 (460) 0.21 f 0.15 (370) 0.20 r 0.08 (460) 0.20 f 0.05 (460) 0.28 f 0.07 (680) 5 1 0 f 96
2.5
3.4
6.0
f
Not detected.
I ,
I,J-DCB
1
0
20
60
40
Days
80
100
120
exposed
Figure 1. Bioconcentration factor vs. days exposed for the chlorobenzenes for a low-exposure dose.
from deviations in chemical concentrations in the tanks and analytical error. The whole fish BCF’s can be converted to lipid BCF’s by multiplying by 12, since the mean lipid content of the trout was 8.5%. Average fish weight increased from 255 to 390 g during the study. There were no significant differences in growth rates among the three groups. Most of the chemicals examined attained equilibrium concentrations in the fish, Environ. Sci. Technoi., Voi. 17, No. 5, 1983 289
Table 11. Chlorobenzenea Concentrations (ng/g ) in Lake Ontario Rainbow Trout
a
1,2,41,2,4,5- 1,2,3,4fish no, weight, kg lipid, wt % TCB TeCB TeCB QCB HCB HCBD 1 2.86 11.9 1.1 0.6 1.4 3.3 27 0.3 2 3.05 4.9 0.3 0.4 0.9 3.9 40 0.2 3 3.73 6.3 0.9 0.9 1.4 4.5 50 0.2 4 4.67 6.1 0.4 0.4 0.6 2.4 20 0.06 5 3.88 8.3 0.8 1.4 5.8 58 0.3 0.6 6 2.39 5.1 0.3 0.3 0.4 1.7 15 0.08 7 1.86 7.7 0.3 0.4 0.6 2.2 20 0.1 8.9 0.7 8 4.07 0.7 0.9 3.3 28 0.2 9.5 0.7 9 3.94 0.6 1.2 4.6 48 0.2 10 1.52 10.3 0.5 0.4 0.7 2.7 21 0.2 1,2-DCB; 1,S-DCB; 1,4-DCB not detected ( < 1ng/g): 1,3,5-TCB; 1,2,3-TCB not detected ( 0.05),but the intercepts are different (P < 0.01). An equation with a slope of 0.85 was reported for a much broader spectrum of compounds that was based primarily on a 32-day study on minnows (5). The difference between the 0.85 slope reported and the 1.0 slope derived in this study may be attributed to several factors. It was not established if the chemicals examined in that study attained equilibrium in the fish, and the concentrations were in the micrograms per liter range. The effect of using nonequilibrated BCF’s in calculating the regression coefficient can be demonstrated by including the value derived for HCB in this study. The relationships between BCF and the partition coefficient for the 12 chemicals examined in this study at the highand low-exposure levels are log BCF = -0.057 + (0.84 f 0.36) log K (3)
r2 = 0.953 and log BCF = -0.333
+ (0.86 f 0.30) log K
(4)
r2 = 0.968 respectively. It is apparent that chemicals that do not attain equilibrium will decrease the regression slope. I t is suggested that this effect will be more pronounced for chemicals with a high octanol-water partition coefficient (e.g., above lo5),which may not reach equilibrium during most laboratory-type studies. Perhaps this study may well demonstrate the difficulties in estimating reliable BCF’s for these types of chemicals and, more importantly, their relationship with the octanol-water partition coefficient as presently applied. Exposure level may also be a contributing factor. Concentrations of the different chemicals used in this study were a a low nanograms per liter level or less, which approximates that monitored in the natural environment. Limited observations that are based on the chemicals examined in this study that reached equilibrium would suggest the BCF would increase assthe exposure level is increased as indicated by the intercept of regression eq 1 and 2. (c) Application of Laboratory BCF’s for Predicting Residue Concentrationsin Field Rainbow Trout. The BCF’s derived in this study that were based on laboratory measurements on relatively large fish at concentrations approach environmental levels were applied to predict the residue levels of rainbow trout in Lake Ontario. With use of concentrations of the chemicals in Lake Ontario waters that were sampled in the fall of 1980 (16),residue concentrations were estimated for rainbow trout on the basis of the BCF’s derived from this study (Table I). These
Table 111. Use of Laboratory BCF's and Chemical Concentrations in Lake Ontario Waters to Predict Residue Levels in Lake Ontario Rainbow Trout concn in Lake mean concn Ontario predicted in Lake waters: concn in Ontario fish, compd ng/L fish, ng/g ng/g 0.6 0.8 0.6 i 0.3 1,2,4-TCB 0.1 0.5 0.5 i 0.2 1,2,4,5-TeCB 1.0 i 0.4 1,2,3,4-TeCB 0.1 0.5 0.2 2.6 3.4 t 1.3 QCB 0.06 0.7 33i: 1 5 HCB HCBD 0.05 0.3 0.2 k 0.08 HCE 0.02 0.01 0.03 i 0.02 Reference 16.
partition coefficients using a one-parameter equation. His conclusions, based on the analysis of literature data, are in excellent agreement with our conclusions (section b, Results and Discussion) which are based on our experimental data.
Acknowledgments We thank Karen Nicol, Lynn Luxon, and Lee Durham for their technical assistance. Registry No. C1, 22537-15-1; 1,2-DCB, 95-50-1; 1,3-DCB, 541-73-1; 1,4-DCB, 106-46-7; 1,3,5-TCB, 108-70-3; 1,2,4-TCB, 120-82-1; 1,2,3-TCB,87-61-6; 1,2,4,5-TeCB, 95-94-3; 1,2,3,4-TeCB, 634-66-2;QCB, 608-93-5;HCB, 118-74-1;HCBD, 87-68-3; HCE, 67-72-1; octanol, 111-87-5; water, 7732-18-5.
Literature Cited values were compared with residue concentrations of the same chemicals that were monitored in adult rainbow trout collected from Lake Ontario in the spring of 1981 (Table 11). There is an excellent agreement between the predicted and measured concentrations for those chemicals that were detectable in Lake Ontario fish with the exception of HCB (Table 111). These results would strongly suggest that, excluding HCB, the chemical concentrations in the water largely control the concentrations in fish for these chemicals. It is evideqt that the behavior of HCB is quite different from the other chemicals. Even if the measured (nonequilibrated) BCF was doubled, the predicted value would still be much lower than that observed in Lake Ontario fish (Table 111). One plausible hypothesis for this response is that the estimated half-life of HCB in fish could be in excess of 7 months (2). In this case, the rate of intake exceeds the capacity of the fish to eliminate HCB and concentrations will continue to increase. From an ecological perspective, substances like HCB, PCB, and DDT, which have long half-lives, would probably be accumulated through the food chain more readily than through water because concentrations in the food organisms generally increase as the trophic level increases (24). In contrast, di-through pentachlorobenzenehave half-lives on the order of several days, and equilibrium conditions can be rapidly attained (8). This study has demonstrated that BCF's can be effectively applied to predict the behavior of a chemical in the natural environment. It has also indicated the importance of deriving these values a t working concentrations that approximate environmental levels. Other variables such as fish size may also be a contributing factor because many laboratory studies use fish that are considerably smaller than those found in the natural environment. There are also differences in BCF's among species where the values for the same chemical can vary several-fold (5). Further studies will be required to determine why some waterborne chemicals attain equilibrium while others do not, Perhaps a chemical's properties or size may limit its uptake across the gill membrane, although limitations on the biotransformation and elimination of the chemical after assimilation may also be an important contributing factor.
Addendum After this paper was submitted, McKay (25) published a paper on the correlation of BCF's with octanol-water
(1) Thomann, R. V. Can. J. Fish. Aquat. Sci. 1981, 38, 280. (2) Niimi, A. J.; Cho, C. Y. Can. J . Fish Aquat. Sci. 1981,38, 1350. (3) Macek, K. J.; Petrocelli, S. R.; Sleight, B. H., 111. "Aquatic Toxicology"; Marking, L. L., Kimerle, R. H., Eds.; America Society for Testing and Materials: ASTM 667, 1979; pp 251-268. (4) Niimi, A. J.; McFadden, C. A. Bull. Environ. Contam. Toxicol. 1982, 28, 11. (5) Veith, G. D.; DeFoe, D. L.; Bergstedt, B. U. J. Fish. Res. Board Can. 1979,36, 1040. (6) Neely, W. B.; Branson, D. R.; Blau, G. E. Environ. Sci. Technol. 1974, 8, 1113. (7) Southworth, G. R.; Beauchamp, J. J.; Schmieder, P. K. Water Res. 1978, 12, 973. (8) Konemann, H.; Van Leeuwen, K. Chemosphere 1980,9,3. (9) Sugiura, K.; Ito, N.; Matsumoto, N.; Michara, Y.; Murata, K.; Tsukakoshi, Y.; Goto, M. Chemosphere 1978, 7, 731. (10) Chiou, C. T.; Freed, V. H.; Schmedding, D. W.; Kohnert, R. L. Enuiron. Sci. Technol. 1977, 11, 475. (11) Konemann, H.; Zelle, R.; Busser, F.; Hammers, W. E. J. Chromatogr. 1979, 178, 559. (12) Young, D. R.; Heesen, T. C.; Gossett, R. W. Water Chlorination: Environ. Impact Health Eff.,Proc. Conf. 1980, 3, 471. (13) Schwarzenbach, R. P.; Molnar-Kubica, E.; Giger, W.; Wakeham, s. G. Environ. Sci. Technol. 1979,13, 1367. (14) Jan, J.; Malnersic, S. Bull. Environ. Contam. Toxicol. 1980, 24, 824. (15) Niimi, A. J. Bull Environ. Contam. Toxicol. 1979,23,20. (16) Oliver, B. G.; Nicol, K. D. Environ. Sci. Technol. 1982,16, 532. (17) Niimi, A. J.; Cho, C. Y. Bull Environ. Contam. Toxicol. 1980, 24, 834. (18) Oliver, B. G.; Bothen, K. D. Anal. Chem. 1980,52,2066. (19) Oliver, B. G.; Bothen, K. D. Int. J.Environ. Anal. Chem. 1982, 12, 131. (20) Bligh, E. G.; Dyer, W. J. Can. J. Biochem. Physiol. 1959, 37,911. (21) Zitko, V.; Carson, W. G. Chemosphere 1977,6, 293. (22) Banerjee, S.; Yalkowsky, S. H.; Valvani, S. C. Environ. Sci. Technol. 1980,14, 1227. (23) Chiou, C. T.; Schmedding, D. W. Environ. Sci. Technol. 1982, 16, 4. (24) Metcalf, R. L.; Sanborn, J. R.; Lu, P. Y.; Nye, D. Arch. Environ. Contam. Toxicol. 1975, 3, 151. (25) McKay, D. Environ. Sci. Technol. 1982, 16, 274.
Received for review May 24,1982. Revised manuscript received November 3, 1982. Accepted December 23, 1982.
Environ. Sci. Technol., Vol. 17, No. 5, 1983
291
