Western Harbour of Alexandria, Egypt
The Western Harbour of Alexandria is the major trade port of the Northern Territory of Egypt. Industrial activities have increased dramatically in this area over the past 20 years. The harbor handles approximately 75% of all ship-borne cargo of the country. As a result of aggressive urbanization and industrialization of the Alexandria region, the coastal waters in general and the Western Harbour in particular have received considerable amounts of treated and untreated industrial, agricultural and domestic wastes (Salem and Sharkawi, 1981). These wastes are derived principally from effluent discharged from the ElMex pumping station to the west of the harbor. The effluent consists of overflow from Lake Maryut (a coastal lagoon heavily polluted mostly by domestic and industrial wastes), and the drainage water from the El-Umum drain and El-Noubariya Canal. Industries that benefit from their quay-side location include a chlor-alkali plant (Misr Chemical Industries). Portland cement factories discharge unknown quantity of wastes into the harbor. Minor amounts of industrial wastes are directly discharged into the harbor through tanneries. Because the harbor is a semi-closed basin with restricted water circulation, it may serve as an entrapment of the wastes introduced from land-based sources as well as from the harbor itself due to shipping activities. Future development and continued operation of Alexandria Harbour is of great economic importance to this region, but these activities may also impact its ecological functioning. Little data are available on the levels of metals in the western harbor. It was therefore deemed necessary to set up a monitoring program to determine the current concentrations of metals in bottom sediments, and to identify any area where high concentrations of potential hazardous contaminants were present in the harbor.
There is also an old dry dock and workshop for ship building and repairs. Located on the southern and eastern sides of the harbour,
The current activities taking place in the harbour are handling, transportation and storage of goods of different types. Wastes enter the harbour environment from the harbour routine activities, sunken vessels, agricultural drains and canals, untreated sewage outfalls, industrial effluents, ships cleaning and discharges and the improper handling of solid wastes from ships
Pollution Sources
Overall, the pollution that ends up in the seas and oceans, originates from four
distinct sources. As represented in Figure 1, the major part of all pollution comes from the land, either through run-off and discharges (via waterways; 44%) or through the atmosphere (33%). Only 12% of all pollution is due to maritime activity and shipping accidents. Dumping of garbage and sewage, as well as the consequences of offshore drilling and mining make up for the rest (resp. 10% and 1%) (Marine Pollution,2013 Geert Potters ISBN 978-87-403-0540-1)
Runoff from the land
The main transport of pollutants from the land to the sea occurs, evidently, through rivers. Rivers take up different forms of waste material from the land, which ends up in the oceans. The most direct load of pollutants comes from the urban and industrial sewage systems that are dumped in the rivers, often preceded by a sanitation step in a water sanitation installation (and even more often not).This urban and industrial runoff, together with agricultural run-off, also contains high levels of nitrogen and phosphorus. These two elements are essential for plant life (and in fact, for the establishment of any food chain in any ecosystem on the planet), but are often only present in the ocean in a limiting concentration to allow for abundant organismal growth. A constant influx of nutrient-rich water from the land can therefore upset any balance in the aquatic ecosystems in coastal areas. As the levels of nitrogen and phosphorus rise, the microalgae populations find themselves less and less restrained in their growth. This often results in so-called algal blooms: massive growth of the unicellular algae in the sea. When they die, the remaining biomass is mineralize by bacteria, which thereby consume so much oxygen that the water beneath these blooms becomes anaerobic. Any fish or invertebrate life there is bound to die. Hence, the so-called eutrophication due to the influx of nutrients is bound to cause severe distortion to the balance of the marine ecosystems. A third source is the runoff from dust particles coming from metal ore and metal mines, washing away in the rivers. These metals can then wreak havoc with the normal metabolism of plant and animal life. According to the US Environmental Protection Agency (EPA), over 40% of watersheds in the western continental US have been contaminated with metals. A large proportion thereof ends up in the oceans. Lastly, there are the large chunks of plastic that are being dumped along the coast, in rivers, etc…. Once they arrive in the ocean, they float along on the oceanic gyres which concentrates this kind of debris in the different oceans. This waste material is the main killer of life in the ocean and may take up to 450 years to be degraded.
Most of marine pollution is simply by accident: When it comes to the amount of pollution that goes into the water, it needs to be said that most of it is simply by accident. As there are a good number of international regulations that forbid express dumping of all different kinds of waste above certain levels. For example, garbage has to be either delivered to shore or burnt in incinerators on board. Incineration is prohibited in special areas (MARPOL Annex V).
The quantitatively largest aquatic form of accidental pollution caused by the maritime sector is also the one that has been highlighted the most:
Oil spills. As crude oil consists of a wide range of different hydrocarbon molecules with different molecular weight and properties, it is not easy to give a concise view of the total damage that is done by an accidental spill. Apart from the highly visible heavy oil that covers the water, the animals and the shores, a large number of lighter components are present as well. These lighter components are likely to do even more damage in the long run, as they are stored in the adipose tissue of different animals in the food chain. Examples of these lighter components comprise the monocyclic and polycyclic aromatic
hydrocarbons, which are difficult to clean up, and bound to cause cancer and other health problems after a few years of continuous exposure.
A certain quantity of polluted sewage water is being produced by people: As people live on ships, a certain quantity of “grey water” (polluted sewage water) is being produced, in the kitchen, the showers…. Part of that goes overboard, the oceans are able to deal with raw sewage through natural bacterial action. On the other hand, the regulations in Annex IV of MARPOL prohibit discharging sewage water within a certain distance of the nearest land, unless the ship is equipped with a certified installation . ·
