Beach tar contamination on the Qatari coastline of the Gulf

Environment

Pergamon

International, Vol. 25, No. 4, pp. 505-513.1999 Copyright 01999 Elsevier Science Ltd Printed in the USA. All rights reserved 0160_4120/99/$-see front matter

PI1SO160-4120(99)00011-2

BEACH TAR CONTAMINATION COASTLINE OF THE GULF

ON THE QATARI

H. Al-Madfa Chemistry Department, Faculty of Science, University of Qatar, Doha, Qatar

M.A.R. Abdel-Moati* Scientific and Applied Research Centre (SARC), University of Qatar, Doha, Qatar

A. Al-Naama Scientific and Applied Research Centre (SARC), University of Qatar, Doha, Qatar

EI 9806-161 M (Received I 7 June 1998; accepted 28 December 1998)

Beach tar concentrations were measured along the Qatari coastlines. Tar concentrations, collected from 11 locations, varied in space and time with values ranging between 2 and 1132 g m-’(average 290 g mm’)ofbeach front. Tar deposition was maximum following the Gulf War oil spill, especially along the northwestern (average 723 g m-l) and northern coasts (average 620 g m-l). With the exception of higher levels off Saudi-Arabia and Oman, the levels of beach tar around Qatar appear to be within the range of previously recorded Gulfvalues. The eastern coast appears to be receiving fresh tar in lower amounts (average 150 g me’)than the western coast (average 304 g m-l), where older tar from earlier spills still persists in large quantities. The application of strict regulations on ballast water disposal in the Gulf led to a clear declination in tar deposition since 1993, reaching baseline limits in some locations. 01999 Elsetier Science Ltd

INTRODUCTION Tar balls in the marine environment

are a derivative of oil or oily compounds which, when released into seawater, lose their volatile fraction by evaporation, and turn into soft brownish black lumps. Due to the relatively high intensity of oil activity in the Gulf, including exploration, exploitation, drilling, storage, transportation, or release from land-based oil industries, tar pollution became a serious problem in the area. The severity of the problem is accentuated by the fact that stranded tar on the beach is a serious nuisance to sea bathers and a threat to the tourist industry, which

is constantly growing in the area. Because of the high molecular weight and resultant inertness of these oil residues, the time needed for their decay may be a matter of years. Because of the heavy oil traffic relative to its size, the Gulf is considered one of the most oil-polluted inland basins in the world. Two main catastrophic events, the Nowruz Field oil spill in 1983 (>68 x lo3 MT of crude oil; Linden et al. 1990) and the Gulf War oil spill in 1991 (0.83-1.5 x lo6 MT of crude oil; Price and Sheppard 1991), heavily impacted the Gulf marine community, causing extensive tar mats along several beaches. Most oil pollution research in the Gulf focused on the distribution of oil in water and sediments. As part of a survey performed during 1984 covering the

*Corresponding author’s permanent address: Oceanography Department, Faculty of Science, Alexandria University, Moharam Bey, Alexandria, Egypt. 505

506

western Coast of the Gulf from Qatar to Kuwait, El-Samra et al. (1986) observed high concentrations of dissolved petroleum hydrocarbons along the Northern Coast of Qatar. These petroleum hydrocarbons were affected by water advected from Saudi Arabia through water circulation. Emara and El-Deeb (1988) studied the distribution of the dissolved and dispersed hydrocarbon in water surface samples collected during September 1985 from a sector extending from Qatar to the UAE coasts. They observed concentrations between 7.7 and 32 ug L-‘. The levels were 2.7 higher than the 1985 Gulf average values. The horizontal and vertical distribution of oil during September-October 1985 and 1986, covering the area east of Qatar to the UAE extending to the Strait of Hormuz and the Gulf of Oman, was dealt with by El-Samra and El-Deeb (1988). They divided the Gulf into three zones according to sources and transport mechanisms of oil pollution, i.e., tanker routes, coastal waters, and offshore oil fields. However, Emara (1990) observed higher levels of petroleum hydrocarbon in the southern Gulf (4.6-25.2 pg L’) compared to the Gulf of Oman (4.4-63 ug L-l). For Qatar-i coastal sediments, Aboul Dahab and Al-Madfa (1993) recorded TPH concentrations of 48 pg g-’ and 248 ug g-’ for the eastern and western beaches, respectively. They decided that possible sources of oil on Qatari coasts are external on the western side but local on the eastern. Al-Lihaibi and Al-Omran (1996) observed TPH levels between 4.0 and 56.2 pg g-l, with an average of 12.3 ug g-’ for offshore Gulf sediments. Concentrations decreased in the southwest direction and were regarded as low, suggesting that physical processes and biodegradation accelerate petroleum removal. However, a higher average, i.e., 32.6 ug g-‘, was mentioned by Al-Lihaibi and Ghazi (1997) for offshore sediments contaminated by offshore oil-related activities. Concentrations showed an increasing trend towards the northwest. Although petroleum residues (tar balls) have been reported from beaches world-wide since the early sixties, only a few surveys concerned tar deposition on the Gulf beaches. Bums et al. (1982) recorded a northsouth trend of decreasing tar along Oman beaches related to the discharging of ballast waters as tankers approach the Strait of Hormuz. Quantitative beach sampling yielded average tar ranging from 5 to 232.5 g rn-’ of shoreline with an overall average of 224 g m-‘. Furthermore, they observed large tar balls (>25 cm diameter) on the seaside of Masira Island and

H. Al-Madfa et al.

added that values were among the highest recorded for any world area, a fact confirmed afterwards by Oostdam (1984). Within a coastal baseline study of pollutants in Bahrain, the UAE, and Oman, Fowler (1985) observed that tar levels varied seasonally and loads on Omani beaches tended to be lower than earlier reports. He added that the majority of tar originates from tankers deballasting and local oil spills. The ranges for tar values were 14-906 g m-l for Bahrain, 4-233 g mm’for the UAE, and l-906 g m-l for Oman. During a survey of the western Gulf, tar balls were encountered at 77% of 53 coastal sites (Price et al. 1989). Using a semi-quantitative scale of 0 (no oil) to 6 (extensive tar pavements), the modal value recorded was 3, denoting moderate amounts of tar at most sites (Price 1993). During a quantitative survey, tar concentrations of l-10 kg mm’of the Gulf shoreline were frequent and concentrations exceeding 10 kg m-’ also commonly occurred (Coles and Gunay 1989). Tar levels ranged up to 100 times the upper values reported for other world regions and up to 10 times values previously reported for other Gulf areas (Price 1993). In the last two decades, beach tar levels have decreased in the N. Atlantic, the eastern Mediterranean, and the east Asian Regions (Limpasaicholl984; Smith and Knapp 1985; Golik and Rosenberg 1987; Golik 1988; Linden et al. 1990) due to improved regulation of oil dumping and the introduction of ships equipped with separate ballast systems. The objective of the present study was to assess the magnitude of beach tar deposition in terms of space and time along the Qatari coastline in comparison to available information on tar pollution in the Gulf area. It could provide decision makers with the necessary data to identify tar-polluted areas and determine priority areas for clean-up operations. STUDY AREA

Sites for monitoring beach tar were chosen according to their economic, social, and cultural importance to Qatar. The investigated area covers more than 500 km along the Qatari coast from Abu Samra on the southwestern coast to Messaied on the southeastern coast (Fig. 1) including 11 beaches. Abu-Samra Beach consists of medium to coarse sand with scattered rocks. Umm Bab and Dukhan are characterised by long, flat sandy beaches bordered by backshore desert vegetation normally used for recreation by local people. The largest onshore oil fields in Qatar lie in Dukhan. Al-Zubara shore consisted of flat rocks covered with a

Tar along Qatar’s coastline

507

tsq

N

ARABIANGULF

n

Rii LAFFAN

Fig. 1. Tar sampling locations along Qatar coastline.

thin layer of sand. Shoals extend offshore intersected by reefs. Al-Areish, Al-Ghariyah, and Fuwairet Beaches are made of coarse sand with sandy banks extending for hundreds of metres offshore. Sandy backshores have scarce desert vegetation while surrounding waters are shallow and shoals are exposed at low tide. These areas are visited for recreation and fishing. Ras Laffan is a new developing industrial area northeast of Qatar with a newly constructed harbour used for the past 2 y for natural gas export. The beach is sandy with shell fragments. Opposite the capital Doha, the beaches are covered with coarse sand, shells, and carbonate rocks. The coastline includes a major commercial harbour and several tourist areas. The southeastern part of the Qatar-i Peninsula is arid and sandy with no vegetation. Al-Wakrah Beach consists of coarse sand, shells, and carbonate rocks. The beaches are used for recreation and fishing, while an

oil-loading harbour and natural gas cleaning station are located in its northern region. Messaied Beach is located south of the Messaied industrial area which harbours several industries as well as loading jetties and oil terminals, characterised by salt sand flats (sabkhas) intersected by sand dunes. The area is used for diving and swimming while a tourist village exists on its southern borders.

MATERIALS

AND METHODS

Beach tar was sampled over several years from 9 locations and for less than a year and approaching 16 months for 2 others. Stations were sampled monthly in triplicate. Sampling was standardised at 1 m wide transects from the most recent high tide level perpendicular down the beach face to the water’s edge at the time of collection (MOOPAM 1989). At each location, three

508

H. Al-Madfa et al.

randomly selected transects were marked across the beach and tar balls within each transect were collected by hand, placed into a labelled plastic bag, and returned to the laboratory where they were weighed (to the nearest 0.01 g) and their general condition (freshness, colour, hardness) was noted. Sand, shells, and other debris were removed from tar surfaces as much as possible. Levels of tar for each beach were reported as weight of tar per linear meter (g m-l) of shore-front (IOC 1984). Conditions of tide, wind, sea state, and waves were noted at the time of sampling. RESULTS

AND DISCUSSION

Due to its situation half way along the western coast of the Gulf, the Qatari Peninsula coastlines are affected by the wind-driven circulation regime within the Gulf. Two anticlockwise gyres prevail in the Gulf northern and southern basins, originating from the Strait of Hormuz, flowing parallel to the Iranian coasts, and diverting off Ras Laffan headland towards the Qatar-i Peninsula, flowing from north to south along the eastem coast. On the other hand, the western coast is affected by a long shore current flowing southward along the Kuwait and Saudi coasts deriving water from the northern and northwestern regions of the Gulf. Although with different magnitudes, tar was always observed in all visited sites. Tar collected from any site at any time ranged from 2 to 1132 g m-’ with an average of 290 g m-i. The mean of tar deposition on each beach as well as the monthly quantitative variations along different sites are presented in Fig. 2. The northwestern and northern areas (Al-Zubara, AlAreish, Al-Ghariayh, and Fuwayrit) are among the most impacted beaches by the Nowruz and Gulf War oil spills, yielding averages of 723, 620, 421, and 442 g m-l, respectively. Satellite images, daily reconnaissance flights, SLAR flights, and IOC surveys declared that not less than 1 mb (0.14 x lo6 MT) affected the Qatari and Iranian coasts during the Gulf War (Tawfiq and Olsen 1993). In addition, these beaches are among the most exposed to traffic activity. The projection of Ras Laffan to the sea at the northeastern coast (Fig. 1) renders the area more exposed to the current flowing from Hormuz as reflected in the increase in average tar deposition (average 2 18 g mm’, range 97-647 g m-l). Several layers of oil were distinguished at some locations along the northern beaches, indicating that these shores have been coated by oil several times. Tar

deposition along the eastern (average 150 g m-i) and western (average 304 g mm’) coasts was significantly less when compared to the northern and northwestern areas. The minimum for the eastern coast was observed along Al-Wakrah Beach during 1996/1997 (range 35-75 g m-‘, average 60 g m-l), and 5-29 g m-l (average 16 g m-l) during 1995/1996 compared to 2-24 g rn-’ (average 6 g m-‘) during 198911991. Despite the low amount of tar deposited along this beach during its history, it seems likely that it is increasingly exposed to tar, especially during the last couple of years (Fig. 2). A survey conducted in September 199 l/June 1992 by SARC (1994) for tar deposition along Qatar, including other beaches, revealed that the ranges for the eastern andwestemcoastswere581013 gm“and78-441 gm-‘, respectively. Deposition rates reached >5000 g m-l at Al-Zubarah and were difficult to assess in other areas. The main factors affecting the beach tar distribution along the eastern and western Qatari coasts are: 1) deballasting areas opposite Messaied and Doha; 2) oil terminals along Messaied, Al-Wakrah, and Doha; 3) harbour activities off Doha, Al-Wakrah, and Ras Laffan; 4) irregular occurrence of accidental oil spillage off Dukhan, Abu Samra (ex: Hasbah 6 well blow out); as well as 5) war activities. The north coast appears to be continuously receiving fresh tar in small amounts, although older tar from earlier spills (Nowruz and Gulf War) still persists in large quantities. The eastern coast is constantly impacted by a regular supply of fresh tar brought to the coast by the prevailing winds and currents, indicating its susceptibility to occasional spills. Tar lumps were generally clean, dark in colour, mostly soft, and broke easily in hand. A mixture of fresh and old weathered tar was observed on the western coast, normally mixed with debris. From the second half of 1993, tar deposition along the Qatari beaches generally declined with different magnitudes (Fig. 2) followed by a period of insignificant monthly changes. Prior to 1993, multi-peak monthly variations were observed along the coastline with the major peak normally following the Gulf War oil spill. This indicates that, by that time, Qatari beaches were intermittently exposed to tar pollution. Statistical t-tests (p < 0.00 1) show a significant difference in overall levels of tar detected before and after the Gulf War. Recent deposition rates could be regarded as baseline for sampled beaches. Such declination in tar deposition coincides with the application of strict regulations and measures regarding the spillage of ballast

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Table 1. Ranges and (mean) of beach tar deposition

(g m-’ of beach-front) levels.

along the Qatari coast compared to other Gulf and world

Range or mean concentrations (g m-‘)

India (west coast)

0.5 - 33

Israel

0 - 662

Golik (1988)

Libya

(1228)

El-Ghirani (1981)

Egypt Malta

2.85 - 406

Cyprus Jamaica

14 - 967

UNEP (1980)

o- 11940

Bermuda

(61) 0.1 - 2516 4 - 233 647 - 2325 (224)

Bahrain

14 - 858

Kuwait

(752) 0 - 28 750

Saudi Arabia Qatar

Aboul-Dahab UNEP (1980)

52.5 - 2440 (879)

Oman (St. Hormuz)

Oostdam (1984)

o- 10

Cameroon U.A.E.

2 - 1132 (290)

the minimum along Abu-Dhabi. Similar observations were made at the Strait of Hormuz beaches in the southern Gulf, showing a range 647-2325 g m“, while along the Omani coasts, a wide range of l-906 g m“ was reported. More recently, near the capital Muscat, tar concentrations ranged from zero to over 5 kg m-l of beach front during 1993-1995 (Coles and Al-Riyami 1996). Comparison between the present data and results from other studies in the Gulf and world-wide (Table 1) indicates that tar ball concentrations are highly variable. High deposition rates were observed in the Gulf region. With the exception of higher levels off Saudi Arabia and Oman, the mean for Qatar1 beaches (290 g m-l) falls within the range of other previously reported Gulf values. Although results give a good indication of the state of oil pollution in Qatar, they emphasize the importance ofthe periodic monitoring of beaches to estimate the extent of their pollution by tar. Tar deposition on beaches can threaten coastal tourism and living coastal and marine resources. According to Atwood et al. (1987), beach users get soiled by tar when beach tar values reach 20 g m-l. Approaching 100 g m-l, beaches become virtually unusable for tourist purposes. Despite the decline in the amount of tar deposition since late 1993 and early 1994 on the Qatari beaches, the average concentrations are still approaching > 100 g m-‘. In view of the steps taken by with

Reference

Location

and Halim (198 1)

Jones and Bacon (1990) Gabche et al. (1998) Butler et al. (1998) Higher Environmental

Committee

(1985)

Fowler (1985) Bums et al. (1982) Fowler (1985) Oostdam ( 1984) KFUPM (1987) Present survey

the government to encourage tourism, several beaches, especially those of the northern and northwestern regions, may have detrimental long-term effects on the tourism industry.

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Jones, M.A.; Bacon, P. Beach tar contamination in Jamica. Mar. Pollut. Bull. 21(7): 331-334; 1990. KFUPM (King Fahd University of Petroleum & Minerals). Marine studies in Saudi Arabian waters of the Arabian Gulf. Dhahran, Saudi Arabia: Research Institute, KFUPM; 1987. Limpasaichol, P. The distribution of tar on beaches along the Andaman Sea Coast of Thailand. Res. Bull. Phuket Mar. Biol. Cont. 34: I-12; 1984. Linden, 0.; Abdulraheem, M.; Gerges, M.; Alam, I.; Behbehani, B.; Borhan, M.; Al-Kassab, L. State ofthe marine environment in the ROPME sea area. UNEP Regional Seas Report and Studies No. (112) Rev. 1. 1990: 33. Available from: Oceans and Coastal Areas Programme Activity Centre, UNEP, Nairobi, Kenya. MOOPAM (Manual of Oceanographic Observations and Pollutant Analysis Methods). Safat, Kuwait: ROPME; 1989: 458. Oostdam, B.L. Tar pollution of beaches in the Indian Ocean, the south China Sea and the Pacific Ocean. Mar. Pollut. Bull. 15: 267-270; 1984. Price, A. The Gulf: Human impacts and management initiatives. Mar. Pollut. Bull. (27): 17-27; 1993. Price, A.R.G.; Wrathall, T.J.; Bernard, S.M. Occurrence of tar and other pollution along the Saudi Arabian shores of the Gulf. Mar. Pollut. Bull. 18: 650-651; 1989. Price, A.R.G.; Sheppard, C.R.C. The Gulf: Past, present and possible future states. Mar. Pollut. Bull. 22: 222-227; 1991. SARC (Scientific and Applied Research Centre). State of oil pollution along the Qatari coastline. Report prepared for SARC. Qatar: University of Qatar; 1994: 52. Smith, S.R.; Knapp, A.H. Significant decrease in the amount of tar stranding on Bermuda. Mar. Pollut. Bull. 16: 19-22; 1985. Tawfiq, N.I.; Olsen, D.A. Saudi Arabia’s response to the 1991 Gulf oil spill. Mar. Pollut. Bull. 27: 333-345; 1993. UNEP (United Nations Environmental Programme). Summary reports on the scientific results of MEDPOL. Part I. UNEP/IG. 18/INF. Athens. New York, NY: UNEP; 1980: 3: 202.