Hydrocarbon status in Florida real estate canals

Volume8/Number 3/March 1977 might think that this is what Governments do. But in maritime affairs, unlike most other matters, too many Ministries have a say. Certain Ministries will fully understand the needs and problems only o f their clients. When national representation at a conference is entrusted primarily to one Ministry, it is important that policy advanced is not weighed too much in favour of its particular interest groups. This difficulty is likely to persist in Britain until our maritime policy is properly coordinated, preferably under the supervision o f a senior Minister. A debate which took place in the House

of Lords on 18 February 1976, on the need for sea use planning elaborates the point. This outline of the problems which have to be overcome if the international regulation o f marine pollution is to be effective may seem discouraging. But it is better to acknowledge the difficulties and to search ways of resolving them than to indulge in unwarranted complacency. I am much indebted to my colleagues on the Advisory Committee on Oil Pollution of the Sea for their help in drawing the attention of those in authority to what still needs to be done.

Hydrocarbon Status in Florida Real Estate Canals W. G. HANSEN, G. BITTON, J. L. FOX and P. L. BREZONIK Department o f Environmental Engineering Sciences, University o f Florida, Gainesville, FL 32611, U.S.A. The level of hydrocarbons present in the sediments of real estate canals on the east and west coast of Florida was determined using gas chromatography. Although the amount of alkanes present was found to be comparatively low, the ratio of the amount of odd carbon-numbered aikanes to even carbon-numbered alkanes suggested that canals on the Gulf of Mexico are receiving an influx of petroleum products. In addition, the most probable number technique was used to enumerate total aerobic heterotrophic bacteria, aerobic hydrocarbon-degrading bacteria, sulfate reducing bacteria, and sulfate-reducing hydrocarbon-degrading bacteria present in the canal sediments. Results showed significantly higher numbers of hydrocarbon degrading bacteria in the sediments of the west coast canals. Demands for waterfront property and water oriented recreation continue to increase. Nowhere in the United States has this demand been so well met as in the State of Florida. Historically, Florida was encouraged by the Federal Government in the Swamp Lands Act of 1850 to recover as much o f the submerged lands as possible for taxation purposes. Particularly affected have been the low-lying mangrove systems. The loose sediment and access to the ocean make this type o f land attractive to developers. Dredging is cheap and the spoil serves as fill. Such developments are most numerous in and around major estuaries and adjacent to the Intracoastal Waterway on the east coast of Florida. The typical result o f such development is the multi-branched system o f fingerlike canals bordered by private property with street access. This rapid and extensive development of the coastline o f Florida has caused a substantial amount o f controversy. Conservational and fishing interests seek to preserve these areas to assure the continued propagation

o f fish and wildlife (Lindall & Trent, 1975). State environmental agencies in Florida are justifiably concerned about the impact of real estate canals on water quality. H y d r o c a r b o n pollutants in marine waters originate from sources other than publicized oil spills. As development of urban areas near the coastal zone continues, so does the amount o f storm r u n o f f from streets and parking facilities. Barada & Partington (1972) reported that r u n o f f into Florida's real estate canals and estuaries may contain large amounts o f pollutants from automobiles, service stations, garages and junkyards. Marinas and other areas o f concentrated boating activity may also be a potential source of hydrocarbon pollution (Davis & Wilson, 1975). Hydrocarbons formed by biological synthesis also constitute a minor but continuing contribution to the natural organic matter in the marine environment (Floodgate, 1972). The impact of hydrocarbons upon marine organisms is only partly understood. It is known, however, that relatively low oil concentrations can exert a substantial impact upon bacterial populations (ZoBell, 1973) and algal photosynthesis (Gordon & Prouse, 1973; Pulich et al., 1974). Hydrocarbons may have detrimental effects upon invertebrates (Anderson et aL, 1974) and the fauna of higher trophic levels. Hydrocarbons entering estuarine waters may associate with suspended materials which eventually accumulate as sediments. Hydrocarbons present in sediments are generally believed to indicate the past influx o f hydrocarbons into the overlying waters (Giger et aL, 1974). For these reasons, the amounts and types o f hydrocarbons which are present in Florida's real estate canal sediments were determined. The measurement o f hydrocarbons in sediments is achieved by extraction with a suitable solvent and analysis 57

Marine Pollution Bulletin

with gas chromatography. Walker & Colwell (1975) found that benzene was the most efficient solvent for extracting petroleum hydrocarbons from estuarine or marine sediments. The ability o f certain microorganisms to degrade various types o f hydrocarbons has been known since the beginning o f this century (Crow et al., 1974). Research during the last few years (Colwell et aL, 1973; Cooney, 1974; H o o d et al., 1975) has indicated that hydrocarbondegrading microorganisms may serve as indicators of hydrocarbon pollution. Absolute numbers of hydrocarlSon-degrading bacteria, as well as the ratios of hydrocarbon-degrading bacteria to total heterotrophic bacteria have been proposed as possible indices. It is now well known that oil may be subject to microbial decomposition under anaerobic conditions and sulphate reducing bacteria have been associated with oil degradation (Novelli & ZoBell, 1944; Rosenfeld, 1947; Shelton & Hunter, 1975). Finger canal sediments are characteristically anaerobic and for this reason, the levels o f sulphate-reducing bacteria and sulphate reducing hydrocarbon-degrading bacteria in these sediments were measured. In this study our objective was two-fold: (1) to evaluate the levels o f hydrocarbons and related bacterial populations in Florida real estate canal sediments, and (2) to determine whether hydrocarbons degraders in these coastal waterways could be used as indicators of hydrocarbon pollution.

Methods The four study areas are located in the east and west coasts o f South Florida (Fig. 1). Two adjacent, dead-end canals about 600 m long were evaluated at each study area. Adjacent pairs of canals were chosen so that observations made at the back, middle, and front of each of the two canals could be considered replicates. The Punta Gorda (PG) and Port Charlotte (PC) canals are

Miles

....

/Bo, Rear

Middle

Front

)

.

~1 ~oro.s.oTo

\ L×

!~

e-.~l

Fig. 1 Map of Florida showing the four study locations on the east and west coasts. PG = Punta Gorda; PC = Port Charlotte; PB = P o m p a n o Beach; LX = Loxahatchee River. Inset: Location of the sampling stations within the two parallel adjacent canals at each study location.

58

contiguous with and on opposite sides o f the Peace River estuary on the Gulf o f Mexico coast. The canals in P o m p a n o Beach (PB) join the Intracoastal Waterway two miles south o f the Hillsboro Inlet. The fourth canal pair extends o f f the eastern side of the north fork of the Loxahatchee River (LX). The latter two canal pairs are on Florida's east coast. The four pairs o f canals are developed around their perimeters to varying degrees. The Loxahatchee River canals were dredged and then abandoned about 15 years ago. One o f the canals was never bulkheaded and small mangroves are recolonizing the shores. Boating in these canals is negligible. In contrast, the canals at P o m p a n o Beach are totally developed and boat traffic is heavy. The two canals at Punta Gorda are relatively young (dredged about 6 yr ago) and are only 25 07odeveloped. Both canals at Port Charlotte are completely developed but harbour only about one-third the number o f boats found in the P o m p a n o Beach canals. The Port Charlotte canals were the only ones receiving street r u n o f f from large conduits. R u n o f f from streets surrounding all other canals is allowed to infiltrate into the ground in swales or is diverted to municipal collection systems. For hydrocarbon analysis, 50 g of wet sediment from the upper 5 cm o f sediment cores (45 cm long × 3.5 int. diam, sterile Plexiglas tubes) were estracted with 50 ml of spectroquality benzene. The benzene phase was then passed through an alumina-silica gel column to remove particulates and some polar compounds and reduced under vacuum to a volume of 0.5 ml. One or twopl o f this concentrate was then injected into a glass column (1.83 m × 0.63 cm diam) packed with 3°7oOV-1 on chromosorb W H P 80/100 in a Tracor 550 gas chromatograph equipped with dual flame-ionization detectors. Initial column temperature upon injection of the sample was 75°C. The temperature was then increased (beginning 4 min after injection) at a constant rate of 5 °/min to a final temperature of 225°C. Alkane hydrocarbons were identified by comparing the corrected retention times of the sample peaks to the retention time of a number of alkane standards. Quantitative analysis o f each unknown was achieved by comparing its area to the area under a peak generated by a known amount o f injected standard. Numbers of bacteria in the sediments were determined using the most probable number (MPN) technique. Known weights o f wet sediments were placed in 100 ml of sterile artificial seawater (Strickland & Parsons, 1972) and serial dilutions were prepared for inoculation into test tubes containing appropriate media. Numbers o f aerobic heterotrophic bacteria were determined in an artificial seawater nutrient broth medium. Incubation was carried out at room temperature for 48 h and turbidity increases above a sterile control were used to score positive tubes. A basal medium of enriched seawater (ESW), as described by Miget et ai. (1969), was used for enumerating aerobic hydrocarbondegrading bacteria. Yeast extract was omitted from the enriched seawater media to assure that the added hydrocarbons were the sole carbon source. A one-to-one mixture of kerosene and 30-weight non-detergent motor oil was sterilized with UV (ultraviolet) light and 0.1 ml was added to each test tube. Most probable number technique was also used to

Volume 8 / N u m b e r 3/March 1977

TABLE 1 Levels of hydrocarbons in Florida Real Estate Canal sediments.

Station

Distance§

Hydrocarbon level (mg/100g wet sediment)

PG PG PG PG PG PG PG

1 2 3 4 5 6 7

R M F R M F B

3.33 1.49 0.35 0.68 0.60 0.68 1.24

PC PC PC PC PC PC PC

1 1 3 4 5 6 7

R M F R M F B

2.20 2.70 4.60 2.70 0.79 0.28 0.11

PB PB PB PB PB PB PB

1 2 3 4 5 6 7

R M F R M F B

2.03 0.29 0.46 1.32 1.72 1.00 0.15

LX LX LX LX LX LX LX

1 2 3 4 5 6 7

R M F R M F B

3.49 2.71 0.13 0.82 1.05 0.99 1.20

Location*

*Location: PG = Punta Gorda; PC = Port Charlotte; PB = P o m p a n o Beach; LX = Loxahatchee River. §Distance: Location of the sampling site within each canal--R = Rear; M = Middle; F ~ Front; B = Bay.

measure the levels of sulphate-reducing bacteria at selected canal stations. Tubes of medium containing Modified Starkey's Medium C (American Type Culture Collection, 1974) with Na-lactate were prepared using artificial seawater. The number of sulphate-reducing bacteria capable of utilizing the artificial hydrocarbon substrate described above was also counted using a Modified Starkey's Medium C where the carbon source consisted of the kerosene-motor oil mixture instead of Na-lactate. After inoculation, the tubes were incubated under anaerobic conditions at room temperature for two weeks to assure recognition of positive tubes. Tubes were scored as positive if black precipitate (ferrous sulphide) was observed.

Results and Discussion Hydrocarbon levels in the Real Estate Canal Sediments The sum of the amounts of the hydrocarbon components detected at each site was calculated and reported as total

hydrocarbons (Table 1). A comparison between the levels of hydrocarbons detected in the Florida real estate canal sediments with the amounts reported by other researchers indicate that chronic hydrocarbon pollution is probably not a water quality problem in the real estate canals studied. The highest level of total hydrocarbons detected was 4.60 mg/100 g wet sediment at a station in the Port Charlotte canals. This is a very low value when compared to levels reported by Mulkins-Phillips & Stewart (1974) for polluted sediments in Chedabucto Bay, Nova Scotia (28.0-36.6 mg/100 g wet sediment). ZoBell & Prokop (1966) and Colwell et aL (1973) indicated that levels below 100 mg/100 g wet sediment are indicative of clean marine sediments. The variations among the estimates given by different researchers is due, in part, to the variations in the levels of natural hydrocarbons contributed by decaying biological materials. Nevertheless, it is apparent that the levels reported here for Florida real estate canal sediments are well below the estimates for polluted sediments. In addition to the quantitative analysis of hydrocarbons in the canal sediments, a qualitative examination of the types and amounts of the hydrocarbon components was made. Gas chromatograms showed the existence of sixteen hydrocarbon components at the thirty-two stations sampled (Table 2). Ten out of sixteen components were identified as n-paraffins ranging from tetradecane (C-14; boiling point = 252 °C) to heptacosane (C-27; boiling point = approx. 400°C). However, not all of the components appeared in the sediments of all the studylocations. A significant difference (95 % confidence level) in the hydrocarbon content between the west coast canals (Punta Gorda and Port Charlotte) and the east coast canals (Pompano Beach and Loxahatchee River) was observed. Chromatograms of the sediments extracts from the four locations are shown in Figs 2 and 3. Chromatograms of Punta Gorda and Port Charlotte sediments are qualitatively similar. Since both sites are on the Peace River estuary the similarity is not surprising. The reason for the same types of hydrocarbons appearing at both Pompano Beach and the Loxahatchee River canals, however, is not clear. However, although the two east coast canals adjoin different water bodies they are similar in terms of tidal flushing, vegetation, fresh water influx and a number of other factors which may explain the observed similarities. The types of hydrocarbon components detected at each location were examined to determine their origin. Blumer & Sass (1972a,b) suggested that the amounts of hydrocarbons with even numbers of carbon atoms were indicative of petroleum residues. In contrast, natural hydrocarbons originating from biological synthesis are

TABLE 2 Mean levels of hydrocarbon components at each location (mg/100 g wet sediment). Location§

C-14

C-17

C-18

C-19

C-20

I1"

PG PC PB LX

0.00 0.00 0.02 0.03

0.07 0.16 0.02 0.06

0.10 0.20 0.00 0.06

0.07 0.12 0.02 0.12

0.06 0.09 0.00 0.00

0.00 0.00 0.02 0.10

C-21 0.10 0.11 0.04 0.07

Hydrocarbon component C-22 I2 I3 C-23 I4 0.09 0.12 0.08 0.10

0.00 0.00 0.07 0.12

0.08 0.11 0.13 0.09

0.11 0.15 0.12 0.20

0.10 0.14 0.20 0.18

I5

I6

C-24

C-27

Odd

Even

Even/ Odd

0.00 0.00 0.19 0.17

0.10 0.13 0.27 0.24

0.17 0.19 0.00 0.00

0.16 0.19 0.00 0.00

0.51 0.73 0.20 0.45

0.42 0.60 0.10 0.13

0.82 0.82 0.50 0.29

§Location: PG = Punta Gorda; PC = Port Charlotte; PB = P o m p a n o Beach; LX = Loxahatchee River. *I1-16: Unidentified peaks.

59

Marine Pollution Bulletin

i

Pompano Beach

8 s[

Punto Gorda E

23 14

_.o

~l f3

14 17 11: ^

171i 19

20 Rt ,

30

40

50

60

R,, rain

min

23

0'ti

Port Chorlotte

18

i2

4

17 I 19

! li ~20

n~

/-~,~

2122 12 23 27

~o

~

,o

Rt,

- - 'a-

6O

rain

R~,

min

Fig. 2 Examples of chromatograms of sediment extracts from the Punta Corda and Port Charlotte real estate canals (west coast). (Numbers above peaks indicate numbers of carbon atoms; 1= unidentified component.) Temperature programming was begun4 min after injection. Range was from 75°C to 225°C at a rate of 5 deg min. Column: 3°70OV-I on chromosorb W HP 80/100 (6ft × ¼in dia.). Carrier gas: He (40 cmVmin). Sample size: 2/~1 (solvent: benzene). Flame ionization detectors were used (air: 360 cmVmin; H~:60 cmVmin).

Fig.3 Examples of chromatograms of sediment extracted from the Pompano Beach and Loxahatchee River real estate canals (east coast). (Numbers above peaks indicate numbers of carbon atoms; l = unidentified peak.) Temperature programming was begun 4 min after injection. Range was from 75°C to 225°C at a rate of 5 deg min. Column: 3070 OV-1 on Chromsorb W HP 80/100 (6 ftx ¼ in dia.). Carrier gas: He (40 cm3/min). Sample size: 2 /A (solvent: benzene). Flame ionization detectors were used (air: 360 360 cmVmin; H 2:60cm3/min).

predominately those having odd numbers o f carbon atoms in their molecules (Han et al., 1968; H a n & Calvin, 1969). The ratio of the sum of the amounts o f even carbon numbered alkanes to the sum o f the amounts of odd carbon numbered alkanes indicates the source of the hydrocarbons. In general, petroleum hydrocarbons have a ratio approaching 1.0, while the indigenous hydrocarbons derived from biological sources exhibit ratios nearer to zero. The mean level of each hydrocarbon component and the calculated ratios for each study location are shown in Table 2. The ratios show that the Loxahatchee River canal sediments have a predominance of odd numbered alkanes (even/odd = 0.29). The ratio at P o m p a n o Beach was somewhat higher (even/odd = 0.50); and the P u n t a Gorda and Port Charlotte canal sediments exhibited the highest ratios (even/odd for both study locations =0.82). The higher ratios at these west coast canals indicate some input o f hydrocarbons from cultural sources.

Gorda and Port Charlotte canals ( X = 3.8 and 16.7°70 respectively) than at the P o m p a n o Beach and the Loxahatchee River canals (.~= 0.2 and 0.04070 respectively). Since the absolute numbers of total aerobic bacteria are relatively constant from one location to another, the observed differences are due to higher levels of hydrocarbon degrading bacteria at the west coast canals. This finding is important because more alkanes of possible cultural origins were found at the west coast canals. It is probable that these same materials are enriching for the populations of hydrocarbon degraders. Numerous studies (Crow et aL, 1974; ZoBell, 1946) have indicated that hydrocarbon-degrading populations will flourish when a broad range of hydrocarbon components such as those found in petroleums are added to those already present in sediments. The observed difference between the levels of aerobic hydrocarbon-degrading bacteria in the west and east coast canals was found to be significant at the 95°70 confidence level. No significant difference was found between the levels of hydrocarbons and hydrocarbon-degrading bacteria at the different stations within each canal. The ratio of hydrocarbondegrading bacteria to total aerobic bacteria did not correlate with the observed hydrocarbon levels in real estate canal sediments. This indicates that hydrocarbondegrading bacteria are not good indicators of the low levels of hydrocarbons we found in these sediments. Colwell et al. (1973) reported that the higher concentrations ofoil in water and sediments (0.5070 w/w)

Bacterial levels in Reai Estate Canal sediments Bacterial populations, in particular those capable of degrading hydrocarbons, were also determined. The results of the tests for total aerobic bacteria and aerobic hydrocarbondegrading bacteria in the canal sediments are presented in Table 3. The percentage of the total aerobic population capable o f degrading hydrocarbons was also calculated. It is apparent that the percentage of aerobic hydrocarbondegrading bacteria was significantly higher at the Punta 60

Volume 8/Number 3/March 1977 TABLE 3 Levels of bacteria in Florida Real Estate Canal sediments (cells/100 g wet sediment).

Location*

Total aerobic bacteria

Aerobic hydrocarbon degraders

103 104 105 105 105 106 105 105

070 hydrocarbon degraders

PG-I PG-2 PG-3 PG-4 PG-5 PG-6 PG-7

1.3 × 8.0x 1.6× 3.9 × 2.5 × 1.3 x 4.9× ,~=3.8×

PC-I PC-2 PC-3 PC-4 PC-5 PC-6 PC-7

3.8 × 105 2.2x 103 9.9x 103 4.4x 104 2.7× 104 1.9 × 105 6.8× 104 ,~= 1.0× 105

7.3 x 1.6x 9.9x 6.0x 5.7x 3.8 x 6.6× P~=2.9 ×

102 103 102 10 2 10 3 10 3 10 3 10 3

0.2 72.7 10.0 1.4 21.1 2.0 9.7 ,~= 16.7

PB-1 PB-2 PB-3 PB-4 PB-5 PB-6 PB-7 PB-8

1,1 × 10 4 3.0× 10 4 1.6× 105 1.6× 10 4 1.0× 105 6.2 × 10 5 6.9 × 10 5 3.0× 10 4 X=2.1 ×105

1.8 × 10 1 1.2x 10 1 7.4x 10 1 5.7 × 10 1 1.2 × 10 1 0.0 0.0 1.7 × 10 2 ,,Y= 5.6 x 10 1

0.2 0.0 0.1 0.4 0.1 0.0 0.0 0.6 P~= 0.2

LX-I LX-2 LX-3 LX-4 LX-5 LX-6 LX-7 LX-8

1.5× 5.6× 2.0× 2.1 × 7.6× '6.8× 8.3 x 6.0x ,~=6.4×

0.0 0.0 1.6x 2.9x 0.0 0.0 0.0 6.2x ,~=3.0x

0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.1 )7=0.04

10 4 10 4 10 5 10 4 10 3 10 4 104 10 4 104

2.5 X 10 2 5.7X 102 5.8x 10 2 3.5 x 103 3.5 × 103 1.1 x 104 1.5x 10 4 )~=4.9× 103

19.0 0.7 0.4 0.9 1.4 0.9 3.1 P~= 3.8

102 101

101 101

*Location: PG = Punta Gorda; PC = Port Charlotte; PB = Pompano Beach; I,X = Loxahatchee River. TABLE 4 Levels of sulfate-reducing bacteria in Florida Real Estate Canal sediments (cells/100 g wet sediment).

Station* PG-2 PG-5 PG-7 PG-8

Total sulphate-reducing bacteria§

Sulphate-reducing hydrocarbon degraders"

2.0× 5.2 × 1.3 × 0.0 ,,Y= 6.6x

10 4 10 3 10 3 10 3

1.8x 10 2 0.0 0.0 2.3 x l0 1 ,~=5.1 x l0 1

PC-2 PC-5 PC-7 PC-8

6.2x 6.4 x 9,4x 7.4x )~= 7,4 x

10 2 10 2 10 2 10 2 l0 2

3.0x 0.0 8.0× 2.4x ,K= 3.4 x

PB-2 PB-5 PB-7 PB-8

l,l x 2.9× 5.8 × 0.0 .~= l.Ox

l0 5 l05 l02

1.3x 10 1 7.4x l0 l 0.0 0.0 )~= 2.2 x I01

1.0× 1.2 x 7.0x 0.0 P~= 2.3 x

10 3 10 3 10 3

LX-2 LX-5 LX-7 LX-8

105

10 3

10 1 10 I 10 1 l0 1

0.0 0.0 0.0 0.0 ,J~= 0.0

*Location: PG = Punta Gorda; PC = Port Charlotte; PB = Pompano Beach; LX=Loxahatchee River. §Grown in Starkey's Modified Medium C plus Na-Lactate. oGrown in Starkey's Modified Medium C minus Na-Lactate with 1070 kerosene-motor oil mixture as a hydrocarbon source.

from Colgate Creek (Chesapeake Bay, Maryland) correlated with higher numbers of petroleum-degrading b a c t e r i a , S i m i l a r l y , H o o d et al. ( 1 9 7 5 ) r e p o r t e d t h a t t h e ratio of hydrocarbon degrading and total aerobic h e t e r o t r o p h i c b a c t e r i a c o r r e l a t e d w e l l (r= 0 . 8 7 ) w i t h levels of hydrocarbons in marsh sediments. However, the c o n c e n t r a t i o n s o f h y d r o c a r b o n s r e p o r t e d b y H o o d et aL (1975) were substantially higher than those found in the Florida real estate canal sediments. The levels of sulphate-reducing bacteria capable of degrading the kerosene-motor oil s u b s t r a t e were measured at selected stations. The purpose was to determine whether sulphate reducers capable of degrading hydrocarbons comprised a significant amount of the total bacterial population in the sediments. The results of t h e s e t e s t s a r e p r e s e n t e d i n T a b l e 4. I t w a s f o u n d t h a t t h e numbers of sulphate-reducing bacteria were relatively high in the sediments. The number of sulphate reducers at Pompano Beach was higher than the number of total aerobic bacteria. This may indicate extreme anaerobic conditions in the sediments of these highly developed canals. No sulphate-reducing bacteria capable of degrading hydrocarbons were detected at the undeveloped Loxahatchee River canals. At Pompano Beach, they were encountered only in the canals and not in the Intracoastal Waterway. The canals at the west coast locations had sulphate-reducing-hydrocarbon-degrading bacteria present in the sediments of the canals and the bay. This research was supported by a grant from the Department of Environmental Regulation, State of Florida. American Type Culture Collection. (1974). Catalogue of Strains. 1 lth Edit., Hatt, H. D. (ed.). Anderson, J. W., Neff, J. M., Cox, B. A., Tatum, H. E. & Hightower, G. H. (1974). Characteristics of dispersions and water soluble extracts of crude and refined oils and their toxicity to estuarine crustaceans and fish. Mar. Biol., 2"/, 75-88. Barada, W. & Partington, W. M. (1972). Report of investigation of the environmental effects of private waterfront canals. Environ. Inf. Cent. Fla. Conserv. Found., Winter Park, FL, 63 pp. Blumer, M. & Sass, J. (1972a). Oil Pollution: Persistence and degradation of spilled fuel oil. Science, !'/6, 1120-1122. Blumer, M. & Sass, J. (1972b). Indigenous and petroleum-derived hydrocarbons in a polluted sediment. Mar. Pollut. Bull., 3, 92-94. Colweil, R. R., Walker, J. D. & Nelson, J. D. Jr (1973). Microbial ecology and the problem of petroleum degradation in Chesapeake Bay. In The Microbial Degradation of Oil Pollutants, pp. 185-198. D. G. Ahearn and S. P. Meyers (eds.), Center for Wetland Resources, Louisiana State University, Baton Rouge, Publication No. LSU-SG-73-01. Cooney, J. J. (1974). Microorganisms capable of degrading refractory hydrocarbons on Ohio waters. Project Completion Report No. 433X for the United States Department of the Interior. State of Ohio Water Resources Center, Ohio State University. Contract No. A-029-Ohio. Crow, S. A., Meyers, S. P. & Ahearn, D. G. (1974). Microbiological aspects of petroleum degradation in the aquatic environment. Extrait de La met (Bulletin de la $ociete franco-japonaise d'oceanographie). Tome 12, No. 2. Davis, H. L. & Wilson, K. D. (1975). Analysis of pollution from marine engines and effects on the environment. National Environmental Research Center (Environmental Protection Agency). Program Element No. IBBo38, Contract No. R-801-799, 225 pp. Floodgate, G. D. (1972). Biodegradation of hydrocarbons in the sea. In WaterPollutionMicrobiology. pp. 153-171. R. Mitchell(ed.). New York: Wiley-lnterscience. Giger, W., Reinhard, M., Schaffner, C. & Stumm, W. (1974). Petroleum-derived and indigenous hydrocarbons in recent sediments of Lake Zug, Switzerland. Env. Sci. Tech., I0, 454--455. 61

Marine Pollution Bulletin Gordon, D. C. Jr & Prouse, N. J. (1973). The effects of three oils on marine phytoplankton photosynthesis. Mar. Biol., 22, 329-333. Han, J. & Calvin, M. (1969). Hydrocarbon distribution of algae and bacteria, and microbiological activity in sediments. Proc. N.A.S., 64,436--444. Han, J., McCarthy, E. D., Van Hoeven, W., Calvin, M. & Bradley, W. H. (1968). Organic geochemical studies, II. A preliminary report on the distribution of aliphatic hydrocarbons in algae, in bacteria, and in a recent lake sediment. Proc. N.A.S., 59, 29-34. Hood, M. A., Bishop, W. S. Jr, Bishop, F. W., Meyers, S. P. & Whelan, T., III (1975). Microbial indicators of oil-rich salt marsh sediments. Appl. Microbiol., 30, 982-987. Lindall, N., Jr & Trent, L. (1975). Housing development canals in the coastal zone of the Gulf of Mexico: ecological consequences, regulations, and recommendations. Mar. Fish. Rev., paper 1163, 3700). Miget, R. J., Oppenheimer, C. H., Kator, H. I. & LaRock, P. L. (1969). Microbial degradation of normal paraffin hydrocarbons in crude oil. In Proc. A P I / F W P C A Joint Conf. on Prevention and Control o f OiI Spills. New York: American Petroleum Institute. Mulkins-Phillips, G. J. & Stewart, J. E. (1974). Distribution of hydrocarbon-utilizing bacteria in Northwestern Atlantic waters and coastal sediments. Can. J. Microbiol., 20, 955-962. Novelli, G. D. & ZoBell, C. E. (1944). Assimilation of petroleum

hydrocarbons by sulfate-reducing bacteria. J. BacterioL, 47, 447--448. Polich, W. M. Jr, Winters, K. & Van Baalen, C. (1974). The effects of a no. 2 fueloiland two crude oils on the growth and photosynthesis of microalgae. Mar. BioL, 28, 87-94. Rosenfeld, W. D. (1974). Anaerobic oxidation of hydrocarbons by sulfate reducing bacteria. J. BacterioL, 54, 664. Shelton, T. B. & Hunter, J. V. (1975). Anaerobic decomposition of oil in bottom sediments. JWPCF, 47, 2256--2270. Strickland, J. D. H. & Parsons, T. R. (1972). A practical Handbook of seawater analysis. FishRes. BdCan., Bulletin 167 (2nd edition), Ottawa. Walker, J. D. & Colwell, R. R. (1975). Extraction of petroleum hydrocarbons from oil-contaminated sediments. Bull. Env. Contamination ToxicoL, 13,245-247. ZoBell, C. E. (1946). Action of microorganisms of hydrocarbons. Bact. Rev., 10, 1-41. ZoBell, C. E. 0973). Microbial degradation of oil: present status, problems, and perspectives. In TheMicrobiaIDegradation of O i l Pollutants. pp. 3-16. D. G. Ahearn and S. P. Meyers (eds.), Center for Wetlands Resources, Louisiana State University, Baton Rouge, Publication No. LSU-SG-73-01. ZoBeil, C. E. & Prokop, J. F. (1966). Microbial oxidation of mineral oils in Barataria Bay bottom deposits. Zast AIg. MikrobioL, 6, 143-162.

Oil Spill in Hong Kong M O L L Y F. S P O O N E R

Marine Biological Association of the U.K., Citadel Hill, Plymouth, Devon, U.K.

Fish farming was seriously but only temporarily affected by a large spill of a very toxic product oil at Hong Kong. Field experiments were set up to follow tainting and depuration. Studies were made of hydrography, water quality, oil in sands, macro- and meio-fauna of shores, and some observations made of possible effects on plankton and open-water fisheries.

open shores in a few months. The other source of pollution from oil which had seeped into the foundation of the tank farm took 6 months to be removed largely by 8' ~. 15' [

A spill o f heavy marine diesel oil (specific gravity 0.89; about 40°70 aromatic content) occurred from the tank farm at Ap Lei Chau, owing to failure o f foundations, on the night o f 8 November 1973. The total loss was estimated as about 4000 tons. Evaporation must have been considerable, water temperature being 23-24°C. Slicks soon spread over East L a m m a Channel and were artificially dispersed there. In Picnic Bay, because of mariculture activities, mopping up with polyurethane foam sheets was tried and was effectively aided by onshore winds. Much oil was stranded on the shores of L a m m a Island--both on the open shores o f George Bay and in Picnic Bay where oil penetrated deep into the sands at the head of the Bay adjacent to the fish farms. In winter the predominant wind direction is from the northeast into the long narrow bay, thus hindering water exchange and the natural flushing of the sands. In summer south-west monsoon conditions improved water exchange and occasional very heavy rainstorms helped to flush some o f the oil out of the coarse sand. Even a year after the spill much oil was still present in deposits at the head o f the bay whereas it was greatly reduced on more 62

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Fig. 1 Area affected by oil from the Hang Kong oil spill.