where 5000 gal of aviation gasoline was spilled in 1969. They found the impact to be severe, with almost a threefold reduction in species diversity and nearly a full year required for complete recovery of the ecosystem. Marine field assessment studies often involve tremendous logistical problems. Handling and storage of equipment and samples is a major consideration in the design of any spill response effort, and, therefore, rapid and simple methods such as those used here are of particular interest. The analyses in this study suggest that the measurements were reliable and that gasoline spilled from the barge did in fact penetrate the water column in the vicinity of Watch Hill Reef. Alkylated benzenes and alkylated naphthalenes were found in water samples a t depths of up to 3.5 m. Because of the difficulties in extrapolating laboratory toxicity tests to field situations, and because of the paucity of information concerning the impact of gasoline spills in the environment, it is difficult to estimate the damage inflicted by the Ocean Barge 250 spill. Nevertheless, the potential long-term, low-level synergistic effects on marine organisms should not be ignored. Literature Cited (1) Smith, J. E., Ed. “Torrey Canyon Pollution and Marine Life”;
a report by the Plymouth Laboratory XIV; Cambridge University Press: New York, 1968. (2) Moore, S. F.;Dwyer,R. L.; Katz, S. W. “A Preliminary Assessment of the Environmental Vulnerability of Machais Bay, Maine, to Oil Supertankers”, Report No. MITSG 73-6, 1973. (3) Hess, Wilmont N., Ed. Washington, D.C., 1978, “The Amoco Cadiz Oil Spill, A Preliminary Scientific Report”, NOAAEPA Special Report. (4) Burns, K. A.; Teal, J. M. Woods Hole, MA, 1971, Woods Hole Oceanographic Institution Technical Report No. 71-69. (5) Blumer, M.; Souza, G.; Sass, J. Mar. Biol. (Berlin) 1970, 5, 195-202. (6) Grose, P.; Mattson, J., Eds. Washington, D.C., 1977, “The Argo Merchant Oil Spill; A Preliminary Scientific Report”, NOAA Special Report.
(7) Scarratt, D. J.; Zitko, V. J . Fish. Res. Board Can. 1972, 29, 1347-50. (8) Hoffman, E. J.; Quinn, J. G. “Hydrocarbon Analyses of Plankton Samples Collected After the Ocean Barge 250 Gasoline Spill”, NOAA Special Report, 1978. (9) Green, D. R. Ottawa, Canada, 1978, National Research Council of Canada Special Report 2, NRCC No. 16565. (10) “Summary Recommendations” of the Trace Metal and Hydrocarbon Seminar sponsored by the Bureau of Land Management, Sept 8-12, 1975. Special report for the Outer Continental Shelf Environmental Studies Program, Bureau of Land Management, 1975. (11) Thompson, C. J.; Ward, C. C.; Bull, J. S. In “Characterization of the World’s Crude Oils”,API Research Project No. 60 (Technical Report BERC/RI 76/8), 1976. (12) Results of the Region I Workshop on Oil Spill Ecological Damage Assessment, Aug 28-31,1977. Report for the Region I and Office of Research and Development, U.S. Environmental Protection Agency, 1977. (13) Lee, R. F.; Sauerheber, R.; Benson, A. A. Science 1972,177, 344-6. (14) DiSalvo, L. H.; Guard, H. E.; Hunter, L. Enuiron. Sci. Technol. 1975,9, 247-51. (15) Crapp, G. B. In “The Ecological Effects of Oil Pollution on Littoral Communities”; Cowell, E. B., Ed.; Institute of Petroleum: London, 1971; pp 181-6. (16) Meinck, F. et al., “Industries-Obuasser”, 2nd ed.; Gustov Fisher Verlong: Stuttgart 536-548, Federal Republic of Germany, 1965. (17) Yevich, P. P.; Barszcz, C. A. Mar. Fish. Rev. 1976,38, 42-3. (18) Brocksen, R. W.; Baily, H. T. Proc. J. Conf. Prev. Control Oil Spills 1973, 783-92. (19) “Quality Criteria for Water”; Office of Water and Hazardous Materials, US.Environmental Protection Agency: Washington, D.C., 1976. (20) Bugbee, S. L.; Walter, C. M. Proc. J . Conf. Preu. Control Oil Spills 1973,725-32. Received for review July 3, 1979. Accepted August 13, 1980. The assistance of funding from the Environmental Protection Agency Grant no. R805477-02and the assistance with the field response by the National Marine Fisheries Services and the United States Coast Guard are gratefully acknowledged.
Molybdenum Blue Applied to Arsenic and Phosphorus Determinations in Fluorideand Silica-Rich Geothermal Waters Robert E. Stauffer Water Chemistry Laboratory, University of Wisconsin, Madison, Wisconsin 53706
Molybdenum-blue without preliminary analytical separations is evaluated for As(III), As(V), total-As, PO4-P, and total-P determinations in geothermal waters with high concentrations of potentially interfering SiO2, F, Mo, Sb. The PO4-P concentrations in typical alkaline, high-C1 boiling hot spring waters from Yellowstone Park are 5 2 pg L-I; these levels are three orders of magnitude lower than previously reported estimates. Estimates of total P in the hot spring waters were not statistically different from PO4-P. No evidence of arsenic species other than soluble arsenite and arsenate was found in the geothermal waters studied. The total arsenic concentrations in the alkaline, medium-high-C1Yellowstone thermal waters were typically in the range 1.5-3.0 mg L-l; the As/P atomic ratios for these waters typically exceed 500.
Introduction The U S . Geological Survey has analyzed arsenic in geothermal waters by using arsine generation prior to a colorimetric step involving silver diethyldithiocarbamate ( I , 2 ) .
Ritchie ( 3 )determined As and Sb in New Zealand geothermal waters by using an involved procedure requiring solvent extraction but avoiding arsine generation. Earlier New Zealand work on As followed the arsine-molybdenum-blue procedure ( 3 ) .Molybdenum and V suppress quantitative arsine generation ( 4 ) ,and stibine (generated along with arsine when S b is present) reacts with silver diethyldithiocarbamate to form a positive interference. Because geothermal waters are notably enriched in Mo, W, and Sb ( I , 5 ) , methods for As which involve arsine generation are potentially biased as well as tedious for geothermal waters. Antimony does not form a colored complex with molybdate since S b does not form an ion homologous to ASo43- or Po43- (6). Phosphorus determinations in the presence of As(V) require selectively reducing As(V) to As(III), a species which does not form a colored molybdate complex. The thiosulfate-metabisulfate reduction step was developed by van Schouwenburg and Walinga (7), refined by Johnson ( 8 ) ,and automated by Goulden and Brooksbank (9). Johnson and Pilson (IO) determined all three species, As(V), As(III), and P, by oxidizing As(II1) with iodate, reducing As(V) with thiosulfate, and differencing the results.
0013-936X/80/0914-1475$01.00/0 @ 1980 American Chemical Society
Volume 14, Number 12, December 1980 1475
Table 1. Selected Solute Constitutents of Generically Classified Yellowstone Geothermal Watersa spring name
bash
Witches Cauldron
Upper
Pork Chop Sylvan unnamed unnamed unnamed
Norris Gibbon Gibbon Shoshone Hot Springs
sample
YS-74-125 YJ-74-10 YF-557 YJ-74-21 YJ-74-23 YT-72-22 YF-448
pH
8.4 7.6 6.0 1.6 4.0 3.0
F
SI02
31 28 7.3 18.5 285 mg L-’. Analyses run in 7/75 on samples stored in polyethylene bottles at room temperature with exposure to light. The Lower Basin samples had been held for 7 yr. Treatments: Raw = no treatment; FU = filtered only: FA = filtered and acidified.
responses due to As(V) and Si02 (unknown). The coefficients in eq 2 were derived from the mean 865/815-nm response ratios for As-free silica standards ( R = 0.708) and silica-free As(V) standards ( R = 1.156). Solve eq 1and 2 for X Iand Xz; call these initial estimates f t l and 2 2 . An improved estimate, XI’(eq 31, accounts
xi’= Y1 - 0.8522
(3)
for the negative As*SiOz interaction. The bias in X1’ is unlikely to exceed 0.05x2. When one uses the iodate procedure and applies eq 1-3, the residual uncertainty in total As arising from silica complexing is -0.5% for a typical silica-rich Yellowstone hot spring water containing 1.5-3 mg As L-l. The error increases as As decreases. Arsenic Species Other Than Arsenate or Arsenite. Two condensed-vapor samples were collected by using acid-permanganate traps over boiling hot springs in the White Creek area of the Lower Geyser Basin. Total As analyses performed on these two samples, using both iodate and persulfate, 530
I
I
I
I
I
yielded responses which were identical with the distilleddeionized water blanks, thus indicating the absence of both arsenic and its potential interferences. We can thus infer that the fraction of total As transported in the alkaline “hot-water dominated” systems which partitions into the vapor phase accompanying near-surface boiling is 200 mg L-1. No significant difference was found for total As for untreated vs. FA, and filtered-unacidified vs. FA sample splits for this important class of springs (Table VII). Discussion
Low levels of As in geothermal waters are associated with acid-sulfate waters derived from condensed vapor (very low C1 concentrations) or, more rarely, ground waters of mixed geothermal and cold-spring origin (29).High concentrations of transition metals, particularly Fe, are often present in the acid-sulfate waters, reflecting acid leaching of country rock (13).In this situation, the analyst is faced with determining diminished levels of As (
