Muhammad Waqar Ashraf | [email protected]
Publication Date: 
Wed, 2011-12-07 02:02

A total of two and half million tons of oil per year enters the marine environment from all sources. Of that, at least 15 comes from natural oil seepages. Human originated sources include chronic discharges from storage facilities and refineries, from tankers and other shipping along major routes, and from accidental events such as spills and pipeline ruptures.
Sources also include diffuse discharges from industrialized municipal areas, offshore oil production, and the atmosphere. 
Total Petroleum Hydrocarbons (TPH) is a term used to describe a broad family of chemical compounds that originally come from crude oil. In this sense, TPH is really a mixture of chemicals. Crude oils can vary in how much of each chemical they contain, and so can the petroleum products that are made from crude oils.
Modern society uses so many petroleum-based products (for example, gasoline, kerosene, fuel oil, mineral oil, and asphalt), and therefore contamination of the environment by them is potentially widespread. Contamination caused by petroleum products contains a variety of these hydrocarbons.
The concentration and distribution of petroleum hydrocarbons is a good indicator of the health of the sea. It can indicate the source of the pollutant that deserves special attention or needs more control.
The International Agency for Research on Cancer (IARC) has determined that one TPH compound (benzene) is carcinogenic to humans and that other TPH compounds (benzo[a]pyrene and gasoline) are probably and possibly carcinogenic to humans.
TPH is released to the environment through accidents, as releases from industries, or as byproducts from commercial or private uses. When released directly into water through spills or leaks, certain TPH fractions will float in water and form thin surface films. Other heavier fractions will accumulate in the sediment at the bottom of the water, which may affect bottom- feeding fish and organisms.
Everyone is exposed to TPH from many sources, including gasoline fumes at the pump, spilled crankcase oil on pavement, chemicals used at home or work, or certain pesticides that contain TPH components as solvents. A small amount of lighter TPH components are found in the air you breathe.
Many occupations involve extracting and refining crude oil, manufacturing petroleum and other hydrocarbon products, or using these products. If you work with petroleum products, you may be exposed to higher levels of TPH through skin contact or by breathing contaminated air. If TPH has leaked from underground storage tanks and entered the groundwater, you may drink water from a well contaminated with TPH. You may breathe in some of the TPH compounds evaporating from a spill or leak if you are in the area where an accidental release has occurred.
More than half of the world's oil passes through the Arabian/ Arabian Gulf whose waters contain very high levels of TPH--probably higher than any other regional sea. This, plus the unique geography of the Saudi Arabian peninsula, where off-coast oil is drilled, stored, and shipped in large quantities and where fish and shellfish are consumed extensively by humans concentrated in coastal towns receiving desalinated sea water, has prompted the need for assessment of the current status of exposure to TPH of marine animals, especially those consumed by humans.
The Arabian Gulf has been subject to inputs of oil pollution from a variety of sources and it has been estimated that oil pollution in the Gulf represents 4.7 percent of total oil pollution in the world. This figure has increased since the Gulf war.
As the Gulf region has approximately two-thirds of the world’s proven oil reserves, problems associated with oil pollution appear to be of greater importance in the Gulf compared with other regions.
This region has undergone considerable development, increased urbanization, industrialization and refineries have become major sources of pollution to the marine environment. Accidental spills and increasing tanker traffic are also contributing factors.
One of the characteristics of the Gulf is that it is relatively shallow, semi-enclosed sea with poor flushing characteristics. Consequently, pollutants undergo slower dispersion than would occur in open oceans. Maintaining good marine environmental quality is important for several economic reasons.
The sea food is of value for both local consumption and export revenue. Oil may enter fish through the skin or gills.  Also, the region relies heavily upon sea water as a source of fresh water through desalination and any pollution could enter the desalination process from the seawater source.
Although risks to human health, due to the presence of petroleum hydrocarbons are not very well documented, the possible consequences of bioaccumulation should not be ignored especially in communities consuming large quantities of fish.
Saudi Arabia has coast lines on the Red sea and Arabian Gulf. While the coast lines are long neither areas are marked by great productivity. According to the Fisheries Statistics of Saudi Arabia, total fishery production of the Kingdom of Saudi Arabia in 1997 was 53170 metric tones. A recent study reported the levels of total petroleum hydrocarbons in several fish species commonly consumed by population in the Gulf. One of the major problems associated with high TPH in fish is tainting, an odor or flavor foreign to the natural aroma of the animal. Tainting of fish is perceived by the public, by fishermen, and by regulatory authorities as an inevitable and undesirable consequence of discharges of oil products into the marine environment.
Higher concentration of hydrocarbons in popular species like grouper, parrot fish and emperors, is probably due to the higher lipid content of their muscle tissue. It is a fact that hydrocarbons are accumulated by simple equilibrium between sea water and body lipids. Moreover, higher TPH concentration in the muscle of the fish may also reflect differences in the marine habitat, feeding habits and the different depths at which they live in the marine environment.
It was observed that most fish species accumulate higher concentration of TPH in winter as compared with summer. This indicated an important fact that TPH concentration not only varies between the tissues of different fish species but it also varied in the same specie depending on the season. The increased hydrocarbon concentration in winter is probably due to the active intake during the cooler season and as a result, large amounts are stored. Another factor is the slackness in movement of fish in winter, provides a favorable condition for the accumulation of hydrocarbons in their muscle tissue.
From the recent and comparative studies it can be concluded that TPH levels in the muscle part of the fish are not as high as could be expected in the Gulf, therefore, consumption of these fish species does not pose a significant health risk to the local population. 

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