Hydrocarbons in a wilderness lake

Volume 7/Number 7/July 1976

Hydrocarbons in a Wilderness Lake The hydrocarbons found in Green Lake, Ontario, Canada, are believed to be of natural origin coming from plant and animal organisms. Over the past several years, a great deal of analytical work has been carried out by our laboratory to measure the nonvolatile hydrocarbon content of open ocean water. A median concentration of 4 #g/l Copb) was observed for surface water taken from widespread areas of the Atlantic Ocean (Monaghan et al., 1974). Even lower concentrations are being observed in a current study of the Pacific Ocean. The origin of such hydrocarbons is of great interest to marine technologists. In our previous work some insight into this question was obtained from compositional data of many typical ocean samples. These results indicated that hydrocarbons were derived both from petroleum and from natural biological activity. However, the likely proportion derived from the two sources could not be estimated. This inability to accurately differentiate between petroleum and biogenic hydrocarbons is due to the lack of information about the composition of biogenic hydrocarbons. From two recent reviews of the subject (Bird & Lynch, 1974; Farrington & Meyers, 1975), it is well known that n-paraffins and olefins are commonly synthesized by micro-organisms. These hydrocarbons may be either oddor even-numbered carbon atom molecules; however, the odd-numbered carbons are expected to predominate. Of less certainty, however, is the degree of complexity that may otherwise occur in hydrocarbons that come from nature. Presence of a pentacyclic triterpane, hop-22(29)ene, in blue-green algae (Bird et al., 1971) supports the concept of complex molecules being present. Additional support for complex composition is provided by studies of selected bacteria (Davis, 1968; Han & Calvin, 1969), mussels (Clark&Finley, 1973), and algae (Stransky etal., 1968) in which unresolved envelopes were observed in gas chromatograms of hydrocarbon fractions.

~

l

~ u

Such data provide only fragmented evidence for the possible presence of biosynthesized, complex hydrocarbon mixtures. In order to directly obtain an integrated picture of nature's hydrocarbons, water from a pristine, wilderness lake was sampled and analysed.

Description of Lake The lake chosen for this study is Green Lake in Ontario, Canada, latitude 46 ° 47" N, longitude 83 ° 25" W. It is oval in shape and is approximately one mile long and one-half mile wide. It is landlocked and is spring fed from ground water only. Green Lake ranges in depth from one to over 30 m. The fish species in the lake include lake trout, walleye, and small-mouth bass. The lake is surrounded by spruce, poplar and birch trees. Limited fishing of the lake does occur both in winter and summer. At the time of sampling, however, the lake had not been fished since ice-out and subsequent turnover of water. The lake was sampled on 29 May 1975, only 15 days after ice-out. This means that the lake water had turned over and what was surface water before ice-out was now near the bottom of the lake and the surface water during sampling was water which had been at a substantial depth during the winter.

Sampling Procedure The stainless steel bucket sampler, stainless steel funnel, glass extraction vessel, and all stoppers were cleaned and tested to show absence of hydrocarbons prior to sampling. Care was taken to avoid contact with the skin during sample handling. Samples were taken from two small boats lashed together and anchored in approximately 13 m of water. Carbon tetrachloride extractions were done immediately after each sample was taken. Six samples totalling 48 I. of water were extracted. These were

_A 0

E n

I

R e t e n t lot1

time,

I

mlrl

Fig. ! Gas ehromatograms of sample and blank.

131

Marine Potlunon Bulletin c o m b i n e d to give a single G r e e n L a k e s a m p l e c o m p o s i t e . T h r e e b l a n k s were collected by extracting the e m p t y glass b o t t l e with c a r b o n t e t r a c h l o r i d e j u s t a f t e r d i s c a r d i n g the p r e v i o u s l y e x t r a c t e d water sample. T h e three s a m p l e b l a n k s were also c o m b i n e d to give a single s a m p l e b l a n k r e p r e s e n t a t i v e o f 24 1. o f water. In s u b t r a c t i n g the b l a n k f r o m the s a m p l e it was first necessary to d o u b l e the b l a n k as m e a s u r e d so that it w o u l d be c o m p a r a b l e in size to the 481. c o m p o s i t e .

Discussion and Results The extracts o f the s a m p l e a n d b l a n k c o n t a i n e d h y d r o c a r b o n s plus o t h e r e x t r a c t a b l e o r g a n i c c o m p o u n d s . The analysis o f these extracts was carried o u t a c c o r d i n g to t h e m e t h o d used for o c e a n water (Brown et al., 1975). T h e total e x t r a c t a b l e o r g a n i c s f o u n d in the G r e e n L a k e c o m p o s i t e was 6/~g/I. T h e total h y d r o c a r b o n c o n t e n t was f o u n d to be 1 . 6 / t g / l . F i g u r e 1 is a gas c h r o m a t o g r a p h i c trace o f the c o m p o s i t e h y d r o c a r b o n s a m p l e a n d the c o m p o s i t e b l a n k ( × 2) in the surface water o f G r e e n L a k e . A P e r k i n - E l m e r 900 c h r o m a t o g r a p h with f l a m e i o n i z a t i o n d e t e c t o r was used. The c o l u m n was 450 cm long, 0.32 cm o . d . a n d c o n t a i n e d 2°70 SE-30 on C h r o m o s o r b G. T h e h e l i u m flow rate was 50 m l / m i n . T h e t e m p e r a t u r e was p r o g r a m m e d f r o m 60°C at a rate o f 8°C min -~ to 275°C. T h e discrete peaks represent n o r m a l p a r a f f i n s over the c a r b o n n u m b e r range Cl~-C3t with the p r e d o m i n a n t ones being o d d n u m b e r e d . Small p e a k s in the C 9 - C , , regions were u n i d e n t i f i e d . P e a k A is an u n i d e n t i f i e d h y d r o c a r b o n which has been f o u n d in n u m e r o u s s a m p l e s o f ocean water. This h y d r o c a r b o n is a p p a r e n t l y a p o l y o l e f i n , a c o m p o u n d also f o u n d in nature. T h e e n v e l o p e u n d e r the n o r m a l p a r a f f i n p e a k s indicates a s m e a r o f h y d r o c a r b o n s . The h y d r o c a r b o n type analysis s h o w n in T a b l e 1 was o b t a i n e d on a C o n s o l i d a t e d M o d e l 21-102 mass s p e c t r o meter. T h e mass s p e c t r u m s h o w e d m e a s u r a b l e ions over the mass range, 12-340. Key ions at b o t h ends o f the mass s p e c t r u m c o r r o b o r a t e the c o m p o s i t i o n . T h e h y d r o c a r b o n type analysis, for e x a m p l e , is p r i m a r i l y d e p e n d e n t u p o n the i n t e r p r e t a t i o n o f f r a g m e n t ions which occur at mass 150 or lower. P r i n c i p a l ions a b o v e mass 150, on the o t h e r h a n d , consist o f f r a g m e n t s , such as: alkyl, a l k e n y l a n d a l k a d i e n y i g r o u p s which are indicative o f the m a j o r

IMCO Symposium on Prevention of Marine Pollution From The lntergovernmental Maritime Consultative Organisation ( I M C O ) , a n d the G o v e r n m e n t o f Mexico 132

TABLE 1 Mass spectrometric analysis of Green Lake composite sample. Relative wt % Saturates n-Paraffins Isopaxaffins ( ycloparaffins arld or ()lefins Total

Aromatics 28 II

I Ring Rtn~ ) Rine

6

~I

1 otai

10

90

h y d r o c a r b o n s as d e t e r m i n e d b y the low m a s s f r a g m e n t s . T h e presence o f a r o m a t i c s was c o n f i r m e d by an i n d e p e n d e n t m e a s u r e m e n t o f the h y d r o c a r b o n fraction by UV a b s o r p t i o n s p e c t r o p h o t o m e t e r . T h e m a s s s p e c t r u m was e x a m i n e d for terpenes a n d n o n e were f o u n d . This eliminates the p o s s i b i l i t y t h a t the lake water was c o n t a m i n a t e d b y a t m o s p h e r i c f a l l - o u t in as m u c h as terpenes are e m i t t e d by the tree species o f the a r e a ( R a s m u s s e n , 1970; S w a n , 1966). P. K. S T A R N E S R. A. B R O W N Analytical and Information Division E x x o n R e s e a r c h a n d E n g i n e e r i n g Co. L i n d e n , N J 0 7 0 3 6 U. S . A .

Bird, C. W., Lynch, J. M., Pirt, S. J. & Reid, W. W. (1971). Tetrahedron Letters, 3189-3190. Bird, C. W. & Lynch, J. M. (1974). Chem. Soc. Rev., 3,309-328. Brown, R. A., Elliott, J. J., Kelliher, J. M. & Searl, T. D. (1975). Adv. Chem. Ser. No. 147, Thomas R. P. Gibb, .lr., Editor, Am. Chem. Soc. 172-187. Clark, Robert C. & Finley, John S. (1973). Techniques for Analysis of Paraffin Hydrocarbons and for Interpretation of Data to Assess Oil Spill Effects in Aquatic Organisms, Proc. Joint Conf. on Prevention and Control of Oil Spills, 161-172. Published by American Petroleum Institute. Davis, J. B. (1968) Chem. GeoL, 3, 155-160. t:arrington, J. W. & Meyers, P. A. (1975). Hydrocarbons in the Marine Environment, Chapter 5, Environmental Chemistry, vol. 1. Burlington House, London. Han, J. & Calvin, M. (1969). Proc. Nat. Acad Sci., USA. 64,436-443 Monaghan, P. H., Brandon, D. E., Brown, R. A., Searl, T. D. & Elliott, J. J. (July 1974). Measurement and Interpretation of Nonvolatile Hydrocarbons in the Ocean, Part 1: Measurements in Atlantic, Mediterranean, Gulf of Mexico and Persian Gulf. For US Dept. of Commerce, Maritime Admin., Washington, DC. NTIS Document No. COM-74-11-634. Rasmussen, R. A. (1970). Environ. Sci. Technol., 4,667-671. Stransky, K., Streible, N. & Sorm, F. (1968). (Turp.)Breb. Coll. Czech. Chem. Commun., Engl. Edn. 33,416-424. Swan, E. P. (1966). ForProd. J., 16, 54-15.

s p o n s o r e d a ten d a y m e e t i n g f r o m 22-31 M a r c h 1976 at A c a p u l c o , M e x i c o . It was a technical s y m p o s i u m intended to p r o v i d e a f o r u m in which to discuss the various scientific, technical a n d e c o n o m i c i m p l i c a t i o n s o f the 1973 I n t e r n a t i o n a l C o n v e n t i o n for the P r e v e n t i o n o f P o l l u t i o n f r o m Ships, with a view to assisting all countries to accept a n d i m p l e m e n t the C o n v e n t i o n . S o m e three h u n d r e d technical experts, e n v i r o n m e n talists, a n d general r e p r e s e n t a t i v e s a t t e n d e d f r o m 71