page_title: Wouri estuary
section_title: Environmental issues
hierarchical_section_title: Wouri estuary / Environmental issues
caption_attribution_description: A Douala street vendor prepares his goods in hopes of making a sale Nov 19, 2006 in , Cameroon, Africa. Vendors often sell many items in small quantities so more customers can afford to purchase them.
context_page_description: The Wouri estuary, or Cameroon estuary is a large tidal estuary in Cameroon where several rivers come together, emptying into the Bight of Biafra. Douala, the largest city in Cameroon, is at the mouth of the Wouri River where it enters the estuary. The estuary contains extensive mangrove forests, which are being damaged by pollution and population pressures.
context_section_description: The ecology of the estuary is under threat from growing pollution from industry, farming and households, threatening both fish yields and human health.
  Sources of pollution include electroplating and oil refinery industries, pest control in cocoa, coffee and banana plantations, and waste organic oils from land transport, process industries and power generation.
  The bulk of human-generated sewage is also released into the estuary without treatment.
  The government infrastructure for controlling pollution is dispersed, weak and ineffective, and there is severe shortage of funding.
  Agriculture is the mainstay of the Cameroon economy. Pesticides are not regulated, and also contribute to pollution. Pesticides that have long been banned elsewhere are still in use, or are being held in leaky storage facilities.
  The growing population is increasing production of export crops such as coffee, cocoa, bananas, palm oil and cotton, using imported pesticides and fertilizers. Typically fertilizers contain urea, ammonia, and phosphorus. Pesticides applied are mostly DDT and other derivatives of organohalogens.
  About 95% of Cameroon's industries are based in or around Douala.
  Their liquid waste is released into the estuary with little or no treatment.
  Douala's Bassa industrial zone ends in the estuarine creek formation of the Dibamba River, discharging pollutants. The wetlands are quickly being colonized by invasive species, and a great number of phytoplankton have been identified, some of which are caused by the pollution.
  The Bonaberi suburb of Douala, with a rapidly growing population of over 500,000, illustrates the urban environmental problems.
  More than 75% of Bonaberi is 2 metres (6.6 ft) above sea level on average.
  With limited land, poor people have encroached into wetlands.
  As of 2002, the dense mangrove swamp forest, which included luxuriant growths of palms, was undergoing extinction due to urbanization.
  The houses and industrial buildings on the cleared land are poorly built, without adequate drainage.
  Pools of stagnant water are breeding grounds for disease.
  Human and industrial waste end up in the channels of the Wouri, reducing its rate of flow.
  River floods and sea incursions may cause rises of water level from 2 metres (6.6 ft) to 5 metres (16 ft) within a few minutes, destroying buildings and washing raw sewage into the wells. Waterborne diseases such as typhus and dysentery are common causes of death.
  Fishery is economically of great importance to Cameroon, with about 40,000 tonnes caught each year, of which one third is exported.
  In 1994, US$60 million worth of fish was exported to Europe, three quarters of which came from 12 industrial-scale fishing companies.
  About 40% of the workforce in coastal Cameroon are full-time unregistered fishers.
  Fish contributes about 44% of the protein in the local population's diet.
  The mangroves of the estuary are spawning grounds for many types of commercial fish, but they are not protected.
  The area covered by mangroves continues to shrink and the fish population has been declining steadily.
  Levels of persistent organic pollutants in the fish are rising.
  A 1991 study showed excessive levels of DDTs and PCBs in fish, shrimp and oysters in the area around Douala.
  High pollution loads of heavy metals such as mercury, lead and cadmium are also a concern.
caption: Street vendor in Douala
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