Environ. Sci. Technoi. 7983, 17, 80-83
coupling of two aniline molecules, our investigation provided evidence for cross-coupling of a quinone derived from a humus constituent and an aniline. It appears that the likelihood of extracting from the soil an imine-type compound composed of a soil phenolic constituent and an aniline is remote, since such a cross-coupling product would be quickly incorporated into the matrix of organic matter. This would explain the relatively fast and strong binding of anilines in the soil. The results from these in vitro experiments serve as a model for demonstrating and explaining an important process occurring in the soil environment. Acknowledgments We thank Alan Freyer for the NMR analyses and Ichen G. Chang for help with the HPLC. Registry No. A, 83560-93-4; B, 83560-94-5; C, 83560-95-6; D, 83560-96-7; E, 83560-97-8;CA, 106-47-8;DCA, 95-76-1; DEA, 579-66-8; V, 121-34-6; Fer, 1135-24-6;Sy, 530-57-4;Prot, 99-50-3; Gal, 149-91-7; laccase, 80498-15-3; a-resorcylic acid, 99-10-5; 0resorcylic acid, 89-86-1; caffeic acid, 331-39-5; phloroglucinol, 108-73-6;resorcinol, 108-46-3; orcinol, 504-15-4.
Literature Cited Bartha, R. ASM News 1980,46,356-360. Bollag, J.-M.; Blattmann, P.; Laanio, T. J . Agric. Food Chem. 1978,26,1302-1306. Chisaka, H.; Kearney, P. C. J . Agric. Food Chem. 1970,18, 854-859. Hsu, T.-S.; Bartha, R. Soil Sci. 1974,116,444-452. Van Alfen, N.K.; Kosuge, T. J . Agric. Food Chem. 1976, 24,584-588. Viswanathan, R.; Scheunert, I.; Kohli, J.; Klein, W.; Korte, F. J . Environ. Sci. Health B 1978,13,243-259. Hsu, T.-S.; Bartha, R. J . Agric. Food Chem. 1976, 24, 1182122.
(8) Parris, G. E. Environ. Sci. Technol. 1980,14,1099-1106. (9) Bollag, J.-M.; Sjoblad, R. D.; Liu, S.-Y. Can J . Microbiol. 1979,25,229-233. (10) Vogel, A. I. A. “Textbook of Practical Organic Chemistry”; Longman: London, 1962;pp 748-749. (11) Sjoblad, R. D.; Bollag, J.-M. Appl. Enuiron. Microbiol. 1977, 33,906-910. (12) Liu, S.-Y.; Minard, R. D.; Bollag, J.-M. J . Agric. Food Chem. 1981,29,253-257. (13) Iwan, J.; Hoyer, G.-A,; Rosenberg, D.; Goller, D. Pestic. Sci. 1976,7,621-631. (14) Bollag, J.-M.; Liu, Sa-Y.;Minard, R. D. Soil Biol. Biochem. 1982,14,157-163. Am. (15) Liu, S.-Y.; Minard, R. D.; Bollag, J.-M. Soil Sci. SOC. J . 1981,45,1100-1105. (16) Bollag, J.-M. In “Aquatic and Terrestrial Humic Materials”; Christman, R. F., Gjessing, E. T., Eds.; Ann Arbor Science: Ann Arbor, MI, 1982;pp 127-141. (17) Stevenson, F. J. In “Bound and Conjugated Pesticide Residues”; Kaufman, D. D., et al., Eds.; American Chemical Society: Washington, D.C., 1976;ACS Symp. Ser. 29;pp 180-207. (18) Parris, G. E. Residue Rev. 1980, 76,1-30. (19) Minard, R.D.; Liu, S.-Y.; Bollag, J.-M. J . Agric. Food Chem. 1981,29,250-253. (20) Briggs, G. G.; Ogilvie, S. Y. Pestic. Sci. 1971,2,165-168.
Received for review May 3,1982.Accepted September 7,1982. Primary funding for this research project was provided by the Office of Research and Development, Environmental Protection Agency (EPA; Grant No. R-808165). The EPA does not necessarily endorse any commercial products used in the study, and the conclusions represent the views of the authors and do not necessarily represent the opinions, policies, or recommendations of the EPA. Additional funding was provided by the Biological Instrumentation Program of the National Science Foundation (Grant No. PCM-8018704)and by the Pennsylvania Agricultural Experiment Station (Journal Series No. 6425).
Dihaloacetonitriles in Drinking Water: Algae and Fulvic Acid as Precursors Barry 0. Oliver Environmental Contaminants Division, National Water Research Institute, Canada Centre for Inland Waters, Burlington, Ontario, Canada L7R 4A6
Ten chlorinated drinking water samples from diverse locations in southern Ontario have been found to contain dihaloacetonitriles, DHAN’s. All samples contained CHC1,CN (range 0.3-8.1ppb) and some samples contained CHBrClCN (range not detected to 1.8 ppb). The average molar DHAN concentration was about 10% of the average molar trihalomethane, THM, concentration. Aqueous chlorination experiments conducted on aquatic fulvic acid and two species of aquatic algae (a blue-green and a green) showed that these materials yielded DHAN’s under conditions similar to those used for water treatment. Introduction The presence of dihaloacetonitriles, DHAN’s, in chlorinated water supplies was reported recently by Trehy and Bieber (1-3). The apparent reason that these compounds had not previously been found is because they decompose on commonly used gas chromatographicphases such as OV 101 and hydrolyze at elevated temperatures and pHs (I). Trehy and Bieber (2) showed that dichloroacetonitrile, CHCl,CN, was produced in good yield from the aqueous solution chlorination of amino acids such as aspartic acid 80
Environ. Sci. Technoi., Voi. 17, No. 2, 1983
and have proposed a reaction mechanism. When bromide was added to the amino acidlchlorine solution at the start of the reaction, a mixture of dichloroacetonitrile (CHCl,CN), bromochloroacetonitrile (CHBrClCN), and dibromoacetonitrile (CHBr,CN) was produced. CHClzCN has been shown to be mutagenic in bacterial assays ( 4 ) , so the presence of these compounds in drinking waters would appear to be undesirable. To date, most investigators of chlorination byproducts have focused their attention on the trihalomethanes, THM’s (5-9). This paper reports the concentration of dihaloacetonitriles in several southern Ontario water supplies and shows that these compounds can be produced by chlorinating aquatic humic substances and algae under conditions used for water treatment. Experimental Section CHCl&N and CHBrzCN were purchased commerically from ICN Pharmacuticals Inc. CHBrClCN was synthesized by reacting cyanoacetic acid with an equimolar mixture of N-chlorosucciniinide and N-bromosuccinimide (proportions and reactions conditions of Wilt (LO)). This reaction yielded a mixture of three DHAN’s, which could
0013-936X/83/0917-0080$01.50/0
0 1983 American Chemical Society
Table I. Dihaloacetonitrile and Trihalomethane Concentrations in Some Southern Ontario Drinking Waters raw raw water water chiorine" CHCl,CN, CHBrClCN, CHCl,, CHBrCl,, CHBr,Cl, TOC, TON, dose, locat ion water source ppm ppm ppm sample PPb ppb PPb PPb PPb 5.5 3.5 2.6 Amherstberg Detroit River 1.7 0.17 1.0 TPb 0.5 0.5 10 7.1 4.8 DSe 1.1 0.9 0.1 3.1 39 2.9 Belleville Bav of Quinte 5.8 0.33 4.0 TP N D ~ 3.7 0.1 42 DS 2.9 ND 9.1 0.8 60 7.6 ND TP Brantford Grand River 6.2 0.67 7.6 9.8 0.9 63 8.1 ND DS 0.9 Dresden 1.1 22 4.6 Sydenham River 5.9 0.81 1.5 TP ND DS 54 12 1.5 1 .o ND 1.1 Grand Bend Lake Huron 2.0 0.13 1.6 TP 0.1 4.5 1.5 0.3 2.1 7.1 3.6 DS 0.3 0.6 2.9 Harrow16 7.9 TP Lake Erie 2.2 0.22 2.6 1.6 2.2 3.2 Colchester 22 10 DS 4.2 1.8 0.1 47 2.8 Napanee ND Napanee River 8.3 0.46 1.2 TP 1.8 0.1 61 3.9 DS ND 2.7 5.4 2.1 1.2 Toronto TP Lake Ontario 2.1 0.18 1.3 0.4 0.4 1.3 5.6 2.2 DS 0.5 0.4 0.1 2.2 Trenton 37 3.3 ND TP Trenton River 5.5 0.34 4.0 0.1 42 4.1 ND 3.0 DS 2.1 Windsor 6.8 3.6 0.9 0.8 Detroit River 1.7 0.15 2.9 TP 2.4 7.8 4.3 0.8 0.9 DS " Chlorine dose = prechlorination dosage t post treatment dosage. Treatment plant (TP) sample. Distribution system (DS) sample (collected a1 mile from treatment plant). Not detected.
be separated by distillation (CHC12CN,bp 112-113 "C; CHBrClCN, bp 138-140 "C; CHBr,CN, bp 169-170 "C). The DHAN analysis was conducted with a Tracor 550 gas chromatograph with electron capture detector by using a 2 m long, 4 mm i.d. column packed with 10% Squalane on Chromosorb P (80/100 mesh). The determination temperatures were as follows: column, 100 "C; injector, 120 "C; detector, 150 "C. Under these conditions, the DHANs were essentially base-line separated from the THMs (retention times: CHC13, 1.54 min; CHC12CN,2.15 min; CHBrC12,2.60 min; CHBrClCN, 4.00 min; CHBr2C1, 4.70 min; CHBr2CN, 8.00 min; CHBr3, 8.90 rnin). The retention times found for DHANs and T H M s in pentane extracts of environmental and laboratory chlorination samples agreed with the pure standards to within f0.03 min. With a 2-pL injection volume, gas chromatographic determinations were reproducible to within f 5 % , and detector response was linear for pentane DHAN concentrations from 1to 100 ppb. Selected samples were also run on a 3% Apolane-87 on 100/120 Chromosorb W(HP) column at 70 "C. Although the separation and peak shapes were not as good on this column as on the Squalane column, the analytical results on the two columns were in reasonably good agreement. The following liquid-liquid extraction procedure was used to enhance recoveries of these fairly water-soluble compounds. To samples (100 mL) in 160-mL hypovials (nominal volume 125 mL, Pierce Scientific) were added 45 g of anhydrous Na2S04and 10 mL of glass-distilled pentane. The bottles were then sealed with Teflon-faced septa and shaken on a rotary shaker (-300 rpm) at -30 "C until all the Na2S04dissolved (at least 1 h). Recovery efficiencies for the method for DHAN's in the 1-10 ppb range from distilled water were as follows: CHC12CN,86 i 4%;CHBrClCN, 88 f 3%; CHBr2CN, 84 f 2%. Detection limits for this pentane extraction/GC procedure were as follows: CHC12CN,-0.05 ppb; CHBrClCN, -0.1 ppb; CHBr2CN, -0.3 ppb. Because the DHAN's were reported to hydrolyze in water, particularly at higher pHs and in the presence of dechlorinating agents ( l ) ,some experiments were conducted to find out the best procedures for sample pres-
ervation. When spiked water samples, buffered to pH 6, 7, and 8 and containing M sodium thiosulfate, were kept at 4 "C for 1 week, only very small DHAN losses (less than 5%) were observed. Therefore, to field samples we added only a small excess of Na2S203to remove the chlorine residual and then stored the samples at 4 "C or less till analysis. Selected analyses on duplicate drinking water samples conducted on the day of sample collection and after 1 week after storage at 4 "C showed virtually no change in DHAN concentration. Storage of samples at room temperature over extended periods is not recommended. Figure 1 shows the DHAN concentrations for spiked samples at pHs 6, 7, and 8 thermostated to 20 "C. It can be seen that significant hydrolysis does occur at this temperature, particularly at pH 8. Laboratory chlorination experiments were conducted with aquatic algae and Mvic acid by using 10 ppm chlorine (NaOCl) and 1 ppm total organic carbon, TOC (algae or fulvic acid). This excess chlorine assured a significant chlorine residual would be present over the entire course of the reaction. Phosphate buffers were used to control the pH at 6,7, and 8 and the reactions were thermostated to 20 f 0.01 "C in a water bath. All analyses were performed in duplicate with a blank, which consisted of a sample to which Na2S20s was added immediately to quench the chlorine residual. Aquatic fulvic acid (48.7% C, 5.4% H, 3.1% N), extracted from Spencer Creek with Mantoura and Riley's XAD-2 resin extraction procedure (111,and two algae species, the blue-green Anabaena Texas 1447 (29.6% C, 5.8% N) and the green Scenedesmus basiliensis (34.2% C, 1.4% N), cultured as previously described (Q),were used for the experiment.
Results and Discussion In order to find out the range of DHAN concentrations in drinking waters, we sampled water supplies from ten Ontario cities that used diverse raw water sources in Dec 1981. The DHAN and THM analyses for these samples are shown in Table I. Samples were collected before and after chlorination at the treatment plant and from the distribution system -1 mile from the plant. DHANs and Envlron. Sci. Technot., Vol. 17, No. 2, 1983
81
Table 11. Yields (ppb) of DHAN's and THM's from the Reaction of Chlorine (10 ppm) with Fulvic Acid and Algae (1 ppm TOC) reaction sample time, h CHC1,CN CHBrClCN CHC1, CHBrC1, CHBr,Cl CHBr, fulvic acid (pH 7) 4 3.4 NW 16 0.6 ND ND ND 33 24 6.5 1.4 ND ND ND 57 48 5.8 ND ND 1.7 ND 120 4.1 ND 80 2.0 ND ND ND blue-green algae (pH 6 ) 4 0.5 0.3 0.5 0.1 ND ND 0.4 24 1.4 0.6 3.4 0.5 7.6 0.6 48 2.3 ND ND 120 3.5 0.4 16 ND ND 0.8 ND blue-green algae (pH 7 ) 4 0.6 ND 3.7 0.2 ND 24 1.9 ND 16 ND 0.6 ND 48 2.5 ND 27 ND 0.9 ND 120 2.3 ND 48 ND ND 1.7 blue-green algae (pH 8 ) 4 0.9 ND 9.8 0.3 ND ND 24 1.9 ND 28 0.9 ND ND 48 1.5 ND 39 1.5 ND ND 120 0.9 ND 59 ND 1.8 ND ND green algae (pH 7) 4 0.5 ND 2.5 0.2 ND ND 1.o 0.1 8.8 24 0.7 ND 48 0.8 0.2 15 0.8 ND ND 120 0.5 0.5 28 1.1 ND ND green algae 4 0.5 0.3 1.3 ND 1.5 1.9 (PH 7,0.3 ppm Br-) 24 1.o 1.o 3.9 0.7 6.9 5.9 48 120 4 24 48 120
green algae (pH 7,1.5 ppm BY)
a
0.7 0.5 0.6 0.6 0.3 0.3
5.9 10 0.7 1.3 2 .o 2.3
11 . 20
1.7 5.0 6.9 13
8.3 13 4.3 10 14 39
1.4 2.8 2.2 6.5 9.8 22
Not detected.
70
CHErClCN
10-
Y
I
0
2
4
6
8
10
TIME (days)
Flgure 1. Concentration of DHAN's as a function of time in buffered water solutions at 20 'C.
T H M s were not found in any raw water samples but were present in all the chlorinated samples. No CHBr2CN or CHBr, were detected in any of the samples. In general, samples from the distribution system contained higher concentrations of DHANs and THMs, which is consistent with earlier studies (12, 13) showing residual chlorine 82
1.1 0.9 0.8 0.9 0.9 0.9
Environ. Sci. Technol., Vol. 17, No. 2, 1983
continues to react with precursors in water distribution systems. CHC12CNwas found in all samples, whereas CHBrClCN was found in samples containing high concentrations of brominated THM's. Brominated THM's (8, 14) and, it ,appears, brominated DHANs, are produced in chlorinated waters that contain inorganic bromide. This is due to the reaction of chlorine with Br- to produce the brominating species hypobromous acid and hypobromite ion (15). For distribution system samples the total molar DHAN concentration averages about 10% of the total molar THM concentration, but the relative concentrations vary widely from city to city. For example, for Dresden the total DHAN concentration is less than 2% of the total THM concentration, whereas, for Harrow-Colchester the total DHAN concentration is 20% of the total THM concentration. The raw water total organic carbon and total organic nitrogen as well as the approximate chlorine dose, obtained from the plant operators, is included for comparison in Table I. A trend toward higher yields of these chlorinated byproducta with higher organic carbon concentrations and higher chlorine doses is apparent. For example, Brantford, which had the highest DHAN and THM concentrations, used the highest chlorine dose and had one of the highest raw water TOC's. Since temperature affects chlorinated byproducts yields (8), we measured the raw water temperatures for the treatment plants. The influent tempertures ranged from 1.7 to 8.9 "C with an average of 4.9 "C. Trehy and Bieber (2,3) showed that certain amino acids react with chlorine to produce DHANs, but the amino acid concentrations in most natural waters is quite low (16,17). We decided to find out whether organic materials present at higher concentrations in natural waters, namely fulvic acid and algae, would yield DHANs on chlorination. The results of these preliminary chlorination experiments are
shown in Table 11. At pH 7, fulvic acid chlorination produced higher DHAN concentrations than chlorination of either algae species. The reaction was not particularly efficient since only -1.3% of the organic nitrogen in the fulvic acid was converted to DHAN’s. Of the two algae species the blue-green Anabaena Texas 1447, which had a much higher organic nitrogen content, produced considerably more DHAN’s on chlorination than the green Scenedesmus basiliensis. The chlorination of the blue-green algae at varying pH is also shown in Table 11. The DHAN yields at pH 6 increase with reaction time, but yields at pH 7 and 8 peak and then decline at longer reaction times. These results show that hydrolysis of DHAN’s occurs in the higher pH solutions. The decline in CHClzCN concentrations from the observed peak concentrations at pH 7 and 8 are much larger than would be predicted from Figure 1. Residual chlorine (-5 ppm) in the fulvic acid and algae solutions (not present in the earlier spiked samples) must either enhance the DHAN hydrolysis rate or react with the DHAN’s. This result has been confirmed by adding chlorine to spiked samples. One possible product of the reaction of chlorine with DHAN’s are trihaloacetonitriles, which have been reported in chlorinated waters by Keith et al. ( 1 8 ) . When bromide (0.3 and 1.5 ppm) is added to the green algae culture prior to pH 7 chlorination, the production of CHBrClCN and the brominated THM’s was greatly enhanced. No CHBr2CN was detected during this experiment. A similar bromide-addition experiment with chlorinated lake water by Trehy and Bieber (I) resulted in the production of a mixture of CHCl,CN, CHBrClCN, and CHBr2CN. In summary, dihaloacetonitriles were found in all chlorinated drinking waters studied. The average molar DHAN concentration is about 10% of the average molar THM concentration. Fulvic acid and algae yield DHA”s on chlorination and are likely the main DHAN precursors in natural waters.
Acknowledgments
I thank George Slawych and Karen Bothen for technical assistance, Bob Hess of the Technical Operations Section
for sample collection, and the Water Quality Branch for TOC and TON analyses. Registry No. CHBr2CN, 3252-43-5; CHCl,CN, 3018-12-0; CHBrClCN, 83463-62-1.
Literature Cited (1) Trehy, M. L.; Bieber, T. I. “Proceedings of the ACS Division
of Environmental Chemistry”; San Francisco, CA, Aug 24-29,1980, American Chemical Society Washington, D.C.; p 447. (2) Trehy, M. L.; Bieber, T. I. Proceedings of the ACS Division of Environmental Chemistry, San Francisco, CA, Aug 24-29, 1980; American Chemical Society Washington, D.C.; p 443. (3) Trehy, M. L.; Bieber, T. I. Water Chlorination: Environ. Impact Health Eff., Proc. Conf., in press. (4) Simmon, V. F.; Kauhanen, K.; Tardiff, R. G. Dev. Toxicol. Enuiron. Sei. 1977, 2, 249. (5) Rook, J. J. Water Treat. Exam. 1974, 23, 234. (6) Symons, J. M.; Bellar, T. A.; Carswell, J. K.; De Marco, J.; Kropp, K. L.; Robeck, G. G.; Seeger, D. R.; Sipcum, C. J.; Smith, B. L.; Stevens, A. A. J. Am. Water Works Assoc. 1975, 67, 634. (7) Oliver, B. G.; Lawrence, J. J. Am. Water Works:Assoc. 1979, 71, 161. (8) Oliver, B. G. Water Chlorination: Environ. Zrhpact Health E f f . ,Proc. Conf. 1979, 3, 141. (9) Oliver, B. G.; Shindler, D. B. Environ. Sci. Technol. 1980, 14, 1502. (10) Wilt, J. W. J. Org. Chem. 1956, 21, 920. (11) Mantoura, R. F. C.; Riley, J. P. Anal. Chim. Apta 1975, 78, 97.
(12) ’National Survey for Halomethanes in DrinGing Water”, Health and Welfare Canada Report No. 77-mD-9, 1977. (13) Young, J. S.; Singer, P. C. J . Am. Water Works Assoc. 1979, 71, 87. (14) Minear, R. A.; Bird, J. C. Water Chlorination: Environ. Impact Health E f f . Proc. Conf. 1979, 3, 151! (15) Helz, G. R.; Hsu, R. Y. Limnol. Oceanogr. 1978, 23, 858. (16) Peake, E.; Baker, B. L.; Hodgson, G. W. Gmchirn. Cosmochim. Acta 1972, 36, 867. (17) Lytle, C. R.; Perdue, E. M. Environ. Sei. Technol. 1981, 15, 224. (18) Keith, L. H.; Hall, R. C.; Henderson, J. E.; Hanish, R. C.; Landolt, R. G. Proc. ACS, Diu. Environ. Chem. 1981,21, 65.
Recieved for review March 19,1982. Accepted September I, 1982.
Environ. Sci. Technol., Voi. 17, No. 2. 1983
83
