Environ. Sci. Technol. 1982, 16, 692-898
Dastillung, M.; Albrecht, P. Mar. Pollut. Bull. 1976, 7, 13-15.
Tissot, B.; Pelet, R.; Rouchache, J.; Combax, A. In “Advances in Organic Geochemistry, 1975”; Campos, R.; Goni, J., Eds.; ENADISMA Madrid, 1977; pp 117-154. Ensminger, A,; Joly, G.; Albrecht, P. Tetrahedron Lett. 1978, 1575-1578.
Gearing, P.; Gearing, J.; Pruell, R.; Wade, T.; Quinn, J. Environ. Sci. Technol. 1980, 14, 1129-1136. Meinschein, W. G. In “Organic Geochemistry”;Eglinton, G., Murphy, M. T. J., Eds.; Springer-Verlag: New York, 1969; Chapter 13, pp 330-356. Haug, P.; Curry, D. J. Geochim. Cosmochim. Acta 1974,
38, 601-610.
Wakeham, S. G. J. Water Pollut. Control 1977, 49,
(39) Carpenter, R.; Bennett, J. T.; Peterson, M. L. Geochim. Cosmochim. Acta 1981,45, 1155-1172. (40) Gschwend, P. M.; Hites, R. A. Geochim. Cosmochim. Acta 1981,45, 2359-2367. (41) Farrington, J. W.; Teal, J. M. Trans. Am. Geophys. Union 1982, 63, 86. (42) Hester, F. J. FA0 Fisheries technical paper no. 162: Rome, 1976. (43) Dexter, R. N.; Anderson, D. E.; Quinlan, E. A,; Goldstein,
L. S.; Strickland,R. M.; Pavlou, S. P.; Clayton, J. R., Jr.; Kocan, R. M.; Landolt, M. NOAA technical memo OMPA-13: Boulder, CO, 1981. (44) Wakeham, S. G. Limnol. Oceanogr. 1977,22,952-957. (45) Collias, E. E.; Lincoln, J. H. Final report to Municipality of Metropolitan Seattle, 1977.
1680-1687.
Eganhouse, R. P.; Simoneit, B. R. T.; Kaplan, I. R. Environ. Sci. Technol. 1981, 15, 315-326.
Wakeham, S. G.; Schaffner, C.; Giger, W. Geochim. Cosmochim. Acta 1980,44, 403-413.
Sutton, C.; Calder, J. A. Environ. Sci. Technol. 1974,8,654. Eganhouse, R. P.; Calder, J. A. Geochim. Cosmochim.Acta 1976,40, 555-561.
Received for review November 17, 1981. Revised manuscript received May 3,1982. Accepted June 9,1982. This research was supported by U.S. Department of EnergylEnvironmental Protection Agency Contract DE-ATO6-76-EV-70040 and U.S. Department of Energy Contract DE-ATO6-76-EV-7002. Contribution No. 1279, School of Oceanography, University of Washington, WB-10, Seattle, W A 98195.
Concentration and Speciation of Dissolved Sugars in River Water Mlnoo S. Sweet and Edward M. Perdue”
Environmental Science/Chemistry Department, Portland State University, Portland, Oregon 97207
rn Gas chromatographic analyses of the alditol acetate derivatives of selected pentoses and hexoses were used to determine dissolved (> (MS),. Accordingly, (TS), can be estimated from the concentration of sugar in the TS fraction alone with the equation (TS), = TS/0.79
+
+
Total organic carbon (TOC) results were obtained on a total carbon analyzer. The concentration of humic substances in river samples was estimated by absorbance of the solution at pH 10 at a wavelength of 420 nm. The calibration curve, which was obtained with solutions of
Table 111. Total Concentrations (pM)of Individual Sugars WR32 WR50 WR56 WR30 WR21 WRlO January 1979 1.87 0.89 0.89 1.47 0.51 Ara 0.03 2.38 1.39 0.99 2.15 0.56 0.01 XYl 0.61 0.63 0.33 0.63 0.66 Man 0.02 1.39 1.14 0.46 0.86 0.94 Gal 0.04 1.42 1.29 1.24 0.56 Glu 0.02 0.96 7.67 5.34 2.42 4.61 6.18 total 0.12 February 1979 0.46 1.52 1.79 0.78 Ara 0.01 0.07 1.75 0.71 0.05 0.00 0.01 1.56 XYl 0.41 0.26 Man 0.06 0.00 0.04 0.49 2.55 0.78 0.51 2.30 0.07 0.00 Gal 0.05 0.96 0.47 Glu 0.00 0.04 0.76 0.22 1.06 6.63 7.46 3.00 total 0.08 March 1979 1.12 1.14 0.09 0.12 0.08 0.60 Ara 1.55 0.96 0.07 0.09 0.08 0.75 XYl 0.61 0.83 0.05 0.28 Man 0.12 0.13 0.01 1.85 0.94 Gal 0.03 0.23 1.25 1.26 0.67 0.07 Glu 0.17 0.63 0.10 0.29 6.39 4.54 total 0.41 0.74 3.51 Ar a XYl Man Gal Glu total
0.08 0.11 0.10 0.07 0.16 0.52
0.06 0.09 0.05 0.10 0.07 0.37
0.07 0.11 0.03 0.07 0.07 0.35
May 1979 1.53 0.73 1.18 0.75 0.62 0.48 1.00 0.43 0.77 0.44 5.10 2.83
0.73 1.37 0.57 1.19 1.06 4.92
sc20
WR67
SR65
WR80
KLlO
0.03 0.00 0.03 0.05 0.09 0.20
0.35 0.58 0.25 0.48 0.46 2.12
0.58 0.51 0.35 0.56 0.68 2.68
0.38 0.46 0.33 0.46 0.46 2.09
0.30 0.43 0.33 0.58 0.78 2.42
0.05 0.00 0.00 0.01 0.05 0.11
0.44 0.24 0.08 0.70 0.26 1.72
1.39 1.90 0.58 1.63 1.09 6.59
1.13 0.97 0.32 1.01 0.57 4.00
0.27 0.24 0.29 0.41 0.43 1.64
0.04 0.01 0.05 0.02 0.02 0.14
0.44 0.37 0.19 0.20 0.30 1.50
0.75 0.58 0.54 0.52 0.59 2.98
0.36 0.51 0.23 0.38 0.33 1.81
0.22 0.38 0.29 0.58 0.33 1.80
0.15 0.04 0.00 0.00 0.04 0.23
0.34 0.33 0.08 0.15 0.36 1.26
0.18 0.24 0.09 0.18 0.17 0.86
0.16 0.22 0.08 0.19 0.18 0.83
0.17 0.11 0.25 0.24 0.21 0.98
6
4
5
GLU
6-
-z
5-
3
s E
4-
Y 8
3*
Y
GAL
I
MAN
1
XYL
0
ARA
s
4
I.
L
A 3
3
2
2 i
2.
1 I.
A
L
WRlO
0 WR21 WRSO WR32 WR5O WR56 S C 2 0 WR67 SR65 WREO KLlO SAMPLING SITE
.02
.04
.06
.08
.1
-12
Abacrbcnce
Flgure 4. Total concentrations &M) of indivldual sugars (January and March 1979).
Flgure 5. Correlation of total sugar concentrations (pM) with absorbance at 420 nm for the May 1979 data.
freeze-dried humic substances that were isolated from the Williamson River (WR50) by adsorption on XAD-7 resin, was linear over a concentration range 0-100 mg/L (28).
approximately conservative mixing of streams containing different sugar concentrations. This spatial pattern is very similar to the previously reported distribution of amino acids in this river system (24). A moderately good correlation between TS and TOC was observed, with sugar carbon accounting for an average of 2.0% of the TOC in this river system. These results are in excellent agreement with previously published values (12-14). Total dissolved sugar concentrations also correlate well with humic carbon (estimated by absorbance at 420 nm and pH lo), as illustrated in Figure 5 for the May 1979 data. For the 4 months of this study, correlation coeffiand 0.97 were observed, implying cients of 0.89,0.80,0.88, that dissolved sugars might be associated with humic substances.
Results and Discussion Analysis of River Water Samples. The spatial variations in total sugar concentrations are apparent from Table I11 and Figure 4. Spring waters (WR10, SC20) contain very low concentrations of dissolved sugars (4month averages of 0.28 and 0.17 pM, respectively). Samples from Klamath Marsh (WR32) and the proximate downstream sites (WR50, WR56) had much higher concentrations of dissolved sugars (4-month averages of 5.31, 6.66, and 3.93 pM, respectively). Further downstream, the observed variation in dissolved sugars is consistent with
Environ. Sci. Technoi., Vol. 16, No. 10, 1982 695
Table IV. Concentrations (MM)of Dissolved Sugar Species Ara XYl samples sites MS PS HS MS PS HS MS WRlO WRIOa WR21 WR30 WR32 WR50 WR50a WR56 WR56a SC20 WR67 SR65 WR80
0.06 0.02 0.00 0.05 0.03 0.01 0.05 0.01 0.00 0.05 0.01 0.01 0.01 0.06 0.00 0.01 0.02 0.71 0.00 0.02 0.01 0.24 1.28 0.01 0.07 0.42 0.64 0.01 0.01 0.49 0.23 0.02 0.06 0.00 1.08 0.02 0.00 0.15 0.00 0.00 0.02 0.18 0.14 0.02 0.00 0.02 0.16 0.02 0.00 0.12 0.04 0.00 KLlO 0.00 0.17 0.00 0.00 a Results obtained in March, 1979.
0.06 0.00 0.08 0.10 1.35 0.54 0.40 0.73 0.00 0.04 0.11 0.00 0.04 0.07
0.00 0.06 0.00 0.00 0.00 0.63 1.15 0.00 0.94 0.00 0.20 0.22 0.18 0.04
0.04 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00
In most other studies of dissolved sugars in fresh waters, very similar sugar concentrations have been observed. For example, Semenov et al. (13),in a study of organic substances in several Soviet rivers, reported average MS and PS + HS concentrations of 1.2 and 3.2 pM, respectively. Stabel (14)reported an average hydrolyzable sugar concentration of 0.7 pM in Schosee, and Weinmann (12)reported an average hydrolyzable sugar concentration of 1.9 pM in the surface waters of Plusssee. Hirayama (19)reported a dissolved sugar concentration of 4.6 pM in Lake Biwa. At most sample sites, total dissolved sugar concentrations decreased irregularly from January to May 1979. Perhaps this trend is indicative of increased microbial activity with increased water temperature. Without a long-term study of temporal variations in dissolved sugar concentrations, no solid conclusions can be drawn. The relative abundances of arabinose, xylose, mannose, galactose, and glucose do not exhibit significant temporal or spatial variations. The 4-month average for the five sugars are 22,24,11,24, and 19 mol %, respectively. These results agree reasonably well with the relative concentrations of individual sugars in other fresh waters (12,14)and with the sugar distribution in a sewage sludge derived fulvic acid (29)but are notably different from the results reported for monosaccharides in seawater (16,17). The approximately equimolar pentose:hexose ratio agrees well with the results of Hirayama (19). Prior studies have shown fructose to be present in natural waters (14,17,20). Since the alditol acetate method results in conversion of fructose to glucitol and mannitol acetates, the measured relative abundances of glucose and mannose are probably overestimated. I t thus seems likely that mannose is a relatively minor fraction of dissolved sugars in the Williamson River system. The distribution of sugars among MS, PS, and HS fractions is given in Table IV and Figure 6. Most of the data were obtained in May 1979, so temporal variations could not be ascertained. The MS fraction wa8 uniformly low, averaging 2.6% for all sites and times. The remaining 97.4% of sugars was approximately equally distributed between PS and HS fractions. With respect to the individual sugars, the average PS/HS ratio varied from 0.7 to 2.8 in the following order: Ara < Xyl < Man < Gal < Glu. The higher percentage of PS for glucose (72%) is consistent with its ubiquitous occurrence in biopolymers. The relative enrichment of hexoses in the PS fraction is illustrated in Figure 7, in which the line of unit slope represents the hypothetical case where each sugar is uniformly distributed among MS, PS, and HS. 696
Envlron. Scl. Technol., Voi. 16, No. 10, 1982
Man
Gal
Glu
PS
HS
MS
PS
HS
MS
PS
HS
0.06 0.00 0.05 0.03 0.47 0.29 0.61 0.19 0.16 0.00 0.08 0.00 0.03 0.25
0.00 0.12 0.00 0.00 0.10 0.32 0.00 0.28 0.67
0.03 0.01 0.01 0.00 0.02 0.01 0.02 0.00 0.01
0.04 0.00 0.09 0.07 1.17 0.39 0.90 0.42 0.16 0.00 0.15 0.03 0.02 0.24
0.00 0.02 0.00 0.00 0.00 0.60 0.93 0.01 0.76 0.00 0.00 0.15 0.17 0.00
0.03 0.01 0.01 0.00 0.00 0.01 0.03 0.00 0.02 0.00
0.13 0.00 0.06 0.07 1.06 0.63 0.68 0.44 0.29 0.04 0.35 0.00 0.03 0.21
0.00 0.09 0.00 0.00 0.00 0.13 0.55 0.00 0.37 0.00 0.00 0.17 0.15 0.00
0.00
0.00
0.00 0.09 0.05 0.00
0.00 0.00 0.00 0.00
0.01 0.00 0.00 0.00
* 3 / 7 9 SAMPLING TRII
WRlO
WRPl WR3O WR3Z WRSO WR56
SC20 WR67 SR68 WR8O KLlO
SAMPLINQ SITE
Flgure 6. Concentrations &M) of dlssohred sugar species (March and May 1979). 100
#
Hexose8
90 -
Pentoses
o
80 lDn ln
5
:,
* /
77 00 --
8 60-
* /
4
50-
b PI
E
0
40-
/
*i/
2 30N
20t
20 -
?k
'
;0
'
0
40
0
'
60
'
80
'
100
trations were positively correlated with discharge, suggesting concomitant mobilization of these components from soils during episodes of surface runoff. Similar mobilization of HS is expected; however, insufficient fractionation data were available to correlate HS with discharge. It is tempting to speculate that the PS/HS ratio may reflect the relative contributions of autochthonous and allochthonous sources to the total sugar concentration in a natural water. It would follow that lake water samples would have higher PS/HS ratios than stream samples, a prediction that is strongly supported by the data for Upper Klamath Lake (KL10) and Klamath Marsh (WR32), for which PS/HS ratios of 24 and 48 were observed. In contrast, an overall average PS/HS ratio of 0.82 was obtained for stream samples. Sugar Content of Aquatic Humus. The probability that humic substances contain sugarlike structural components is intuitively quite high, considering the very high carbohydrate content of biomass from which humus is derived. It is certainly possible, however, that most carbohydrates are simply recycled in the biosphere through the action of microorganisms. The most comprehensively studied humic substance is the Prince Edward Island soil fulvic acid used by Schnitzer and co-workers (1). Using potentiometric titrations to estimate carboxyl and phenolic content and quantitative acetylation to measure the sum of phenolic and alcoholic hydroxyl groups, Schnitzer and co-workers have determined that their soil fulvic acid contains 7.7 mmol/g carboxyl groups, 3.3 mmol/g phenolic groups, and 3.6 mmol/g alcoholic hydroxyl groups. A summary of their work is given by Gamble and Schnitzer (30). Assuming that all alcoholic hydroxyl groups are present as sugar moieties with equal proportions of pentoses and hexoses (as observed in this study), it is possible to estimate the maximum fraction of carbohydrate carbon in their fulvic acid. The acetylation reaction detects only free hydroxyl groups. In a typical pyranose, there are 3-4 free hydroxyl groups/6 carbon atoms, depending on whether the pyranose is covalently bonded to 1 or 2 other structural units. Likewise, a furanose contains 2-3 free hydroxyl groups/5 carbon atoms. Therefore, the 3.6 mmol/g alcoholic hydroxyl groups in Schnitzer’s soil fulvic acid corresponds to 5.7-8.1 mmol/g carbohydrate carbon, which is 13-19% (w/w) of the carbon content of the fulvic acid. The probable presence of carbohydrate moieties in both soil and aquatic humus is also strongly suggested by several recent ‘H and 13C NMR studies (2-5). Worobey and Webster (2) suggest that carbohydrates are very important structural components of humus and that these structural moieties are converted into aromatic structures by extraction procedures that utilize strong acid or base solutions. Hatcher et al. (3) and Wilson et al. ( 4 ) have concluded that aquatic humus from both marine and freshwater environments contains significant amounts of 0alkyl carbon, probably in the form of sugarlike moieties. Wilson et al. (5),using both ‘H and 13CNMR, have concluded that 27% of the nonexchangeable H in a soil humus sample is bonded to the carbon atoms of sugarlike moieties. From their data regarding elemental ratios of C, H, and N, together with the reasonable assumptions that their sample of humus contains approximately 50% (w/w) carbon and approximately 12 mmol/g exchangeable H, the results of Wilson et al. (5) imply that about 15% of the carbon in their sample could be in the form of sugar moieties. A n even more directly quantitative determination of the carbohydrate content of a soil humus sample (Contech
fulvic acid) was recently reported by Wershaw et al. (6), who used 13C-enriched methylating agents to convert carboxyl, phenolic, and alcoholic hydroxyl groups into their respective methyl esters and methyl ethers. The relative abundances of carboxyl, phenolic, and alcoholic hydroxyl groups were estimated to be 2.5:l.Ol.l by 13C NMR spectroscopy on the 13C-enrichedmethylated derivatives. According to Wershaw et al. (6),the Contech fulvic acid is equivalent to the Prince Edward Island soil fulvic acid used by Schnitzer and his co-workers. From the carboxyl content of the latter material (7.7 mmol/g), the alcoholic hydroxyl content of Contech fulvic acid is estimated to be 3.4 mmol/g, in excellent agreement with the value of 3.6 mmol/g for Schnitzer’s fulvic acid. Like the acetylation method used by Schnitzer and co-workers, the methylation procedure of Wershaw et al. (6)detects only free hydroxyl groups, so the calculation procedure used earlier for Schnitzer’s fulvic acid is also applicable to the data of Wershaw et al. (6). By assumption of a 1:l ratio of pentoses to hexoses, the 3.4 mmol/g of alcoholic hydroxyl groups in Contech fulvic acid corresponds to 5.5-7.6 mmol/g carbohydrate carbon. Thus, about 13-18% (w/w) of the carbon in Contech fulvic acid could be in the form of carbohydrate moieties. These results are in excellent agreement with both the data of Gamble and Schnitzer (30) and the results of Wilson et al. (5). The results obtained by wet-chemical and lH and 13C NMR methods all indicate that approximately 15% of the carbon atoms in humus could be present as sugar moieties. It is of interest to compare this upper limit with the actual sugar concentrations obtained in this study. For example, the average TS at WR50 was 6.66 pM, consisting of approximately a 1:l mixture of pentoses and hexoses. This concentration corresponds to a sugar carbon concentration of 0.44mg/L, which is only 2.8% of the average TOC value at WR50 (16 mg/L). From absorbance measurements, approximately 60% of the TOC at WR50 is estimated to be humus carbon, and from the data in Table IV, a similar fraction of dissolved sugars at that sample site is humicbound. Thus, about 2.8% of the aquatic humus carbon is identifiable as sugar carbon. This value is far less than the upper limit of 15% that was derived from measurements of alcoholic hydroxyl groups in humus. It is safe to assume that simple monosaccharide and polysaccharide fragments are not significant structural units in humus, because they would both be expected to yield sugars directly upon hydrolysis. At this time, the nature of the remaining four-fifths of the alcoholic hydroxyl groups is purely speculative. Certainly, the simple oxidation products of aldoses (aldonic acids, aldaric acids, and uronic acids) could account for both the relatively high alcoholic hydroxyl content and low sugar content of humus. None of the carboxylic acid derivatives of sugars can be reduced to alditols by NaBH4 and thus could not be detected at all by the analytical methodology used in this study. Uronic acids have, in fact, been detected in soil humic substances (31) and in natural waters (12),but only in very low concentrations.
Conclusions Total dissolved sugar concentrations ranged from 0.1 to 7.7 kM, with approximately equal concentrations of arabinose, xylose, galactose, and glucose, and with lower concentrations of mannose. Spring waters were quite low in dissolved sugars, while colored sample sites downstream from Klamath Marsh had much higher sugar concentrations. Fractionation studies demonstrated that monosaccharide (MS) concentrations were quite low at all samEnviron. Sci. Technol., Vol. 16, No. 10, 1982 697
Envlron. Sci. Technol. 1082, 16, 698-702
ple sites. The relative abundances of polysaccharides (PS) and humic-bound saccharides (HS) were highly variable. In lake and marsh waters, PS accounted for nearly all dissolved sugars,while in stream samples, PS and HS were almost equally abundant. Hexoses (particularly glucose) were relatively enriched in the PS fraction and relatively deficient in the HS fraction. Identifiable sugars accounted for an average of 2.0% of the total organic carbon in the Williamson River system. This value is much lower than the carbohydrate contents of humic substances as estimated by analysis of alcoholic functional groups or by 13C and lH NMR studies, suggesting that most of the sugarlike structural units in humic substances are probably not in the form of simple monosaccharide or polysaccharide moieties. Literature Cited (1) Schnitzer, M.; Khan, S. U. “Humic Substances in the Environment”; Marcel Dekker: New York, 1972. (2) Worobey, B. L.; Webster, G. R. B. Nature (London) 1981, 292,526-529. (3) Hatcher, P. G.; Rowan, R.; Mattingly, M. A. Org. Geochem. 1980,2,77-85. (4) Wilson, M. A.; Barron, P. F.; Gillam, A. H. Geochim. Cosmochim. Acta 1981,45, 1743-1750. ( 5 ) Wilson, M. A.; Jones, A. J.; Williamson, B. Nature (London) 1978,276,487-489. (6) Wershaw, R. L.; Mikita, M. A.; Steelink, C. Environ. Sci. Technol. 1981,15,1461-1463. (7) Clark, F. E.; Tan, K. H. Soil Biol. Biochem. 1969, I , 75-81. (8) Cheshire, M. V.; Anderson, G. Soil Sci. 1975,119,356-362. (9) deHahn, H.; deBoer, T. Water Res. 1978,12,1035-1040. (10) Leenheer, J. A,; Malcolm, R. L. U.S. Geol. Suru. Water Supply, Paper 1817-E, 1973. (11) Dubois, M.; Gilles, K. A,; Hamilton, J. K.; Rebers, P. A.; Smith, F. Anal. Chem. 1956,28, 350-356. (12) Weinmann, G. Arch. Hydrobiol., Supp. 1970,37,164-242. (13) Semenov, A. D.; Pashanova, A. P.; Kishkinova, T. S.; Nemtseva, L. I. Sou. Hydr.: Selected Papers (Engl.!!‘rand.) 1967,5,549-553.
(14) Stabel, H. Arch. Hydrobiol., Supp. 1977, 53, 159-254. (15) Ruchti, J.; Kunkler, D. Schweiz. 2.Hydrobiol. 1966,28, 62-68. (16) Degens, E. T.; Reuter, J. H.; Shaw, K. N. F. Geochim. Cosmochim. Acta 1964,28,45-66. (17) Mopper, K.; Dawson, R.; Liebezeit, G.; Ittekkot, V. Mar. Chem. 1980,10, 55-66. (18) Dutton, G. G. S.; Gibney, K. B.; Jensen, G. D.; Reed, P. E. J . Chromatogr. 1968, 36, 152-162. (19) Hirayama, H. Anal. Chim. Acta 1974, 70, 141-148. (20) Geller, A. Arch. Hydrobiol., Supp. 1975, 47, 295-324. (21) Sawardecker, J. S.; Sloneker, J. H.; Jeans, A. Anal. Chem. 1965,37,1602-1604. (22) Perdue, E. M. ACS Symp. Ser. 1979, No. 93, Chapter 5. (23) Leenheer, J. A.; Huffman, E. W. D., Jr. J . Res. U.S. Geol. Survey 1976, 4 , 737-751. (24) Lytle, C. R.; Perdue, E. M. Environ. Sci. Technol. 1981, 15, 224-228. (25) Griggs, L. J.; Post, A.; White, E. R.; Finkelstein, J. A.; Moeckel, W. E.; Holden, K. G.; Zarembo, J. E.; Weisback, J. A. Anal. Biochem. 1971,43, 369-381. (26) Cheshire, M. V.; Mundie, C. M. J . Soil Sci. 1966, 17, 372-381. (27) Vallentyne, J. R.; Bidwell, R. G. S. Ecology 1956, 37, 495-500. (28) Blunk, D. personal communication, Portland State University, 1979. (29) Holtzclaw, K. M.; Schaumberg, G. D.; LeVesque-Madore, C. S.; Sposito, G.; Heick, J. A.; Johnston, C. T. Soil Sci. SOC. Am. J . 1980,44,736-740. (30) Gamble, D. S.; Schnitzer, M. In “Trace Metals and Metal-Organic Interactions in Natural Waters”; Singer, P. C., Ed.; Ann Arbor Science: Ann Arbor, MI, 1973. (31) Ivarson, K. C.; Sowden, F. J. Soil Sci. 1962, 94, 245-250.
Received for reuiew March 18,1981. Revised manuscript received June 3,1982. Accepted June 24,1982. The work upon which this publication is based was supported in part by funds provided by the Office of Water Research and Technology, U.S. Department of the Interior, Washington, D.C., as authorized by the Water Research and Development Act of 1978.
Occurrence of Organotin Compounds in Ontario Lakes and Rivers R. James Magulre,” Ylu Kee Chau, Gerald A. Bengert, and Ellzabeth J. Hale Environmental Contaminants Division, National Water Research Institute, Department of Environment, Canada Centre for Inland Waters, Burlington, Ontario L7R 4A6, Canada
Paul T. S. Wong and Orysla Kramar Great Lakes Biolimnology Laboratory, Department of Fisheries and Oceans, Canada Centre for Inland Waters, Burlington, Ontario L7R 4A6, Canada
The presence of butyltin and methyltin species is reported for the first time in lakes, rivers, and harbors in Ontario. Concentrations of tri-n-butyltin in Collingwood Harbor, a marina in Lake St. Clair, Toronto Harbor, and % the L C : ~value for a sensitive Ramsey Lake are 1 ~ 0 of aquatic species, rainbow trout yolk sac fry. The species B u s h + , Bu2Sn2+,and inorganic tin are concentrated by factors of up to lo4 in the surface microlayer relative to subsurface water. Concentrations of methyltin and dimethyltin are high in Kingston Harbor and Whitby Harbor and in industrial areas such as Lake St. Clair. H
Introduction Organotin compounds are used in three major ways, viz., as stabilizers for polyvinyl chloride, as catalysts, and as biocides (1). The increasing annual use of organotin 608
Envlron. Sci. Technol., Vol. 16, No. 10, 1982
compounds raises the possibility of environmental pollution. Organotin compounds are a class of compounds about which more information is sought under Canada’s Environmental Contaminants Act (2) regarding toxicology and environmental fate. The toxicity of tin compounds to humans (3),terrestrial animals ( 4 ) , and phytoplankton (5) has been extensively studied. In general, organotin compounds are more toxic than inorganic tin compounds. Progressive introduction of organic groups to the tin atom in any R,S~L(~-”)+ series produces maximal biological activity against all species when n = 3, i.e., for the triorganotin compounds. However, within the class of trialkyltin compounds, there are considerable, and as yet unexplained, variations in toxicity with the nature of the alkyl group (6). For insects, trimethyltin compounds are most toxic; for mammals, the triethyltin compounds; for Gram-negative bacteria, the
0013-936X/82/0916-0698$01.25/0
0 1982 American Chemical Soclety
