JEDDAH, 10 September 2006 — Officials of the Jeddah municipality have made an application to the Ministry of Agriculture in Makkah to import the water hyacinth into the Kingdom. Introducing the hyacinth — a species of water cabbage — to the lake of effluent northwest of Jeddah, they believe, will reduce the threat of mosquito-borne disease and infection.
Saleh Al-Tuwaijri, manager of the Jeddah branch of the Ministry of Agriculture, said that an application had been sent to the Makkah office and forwarded to Riyadh for final approval. He, however, said the plant could present a threat to the environment and to the infrastructure of the city’s sewage projects. Experience elsewhere, including Egypt, Sudan and the US, has shown that the plant spreads into pipes and sewage systems forming blockages. Removing or eliminating is expensive and, once the plant has established itself, is very difficult to achieve.
Water hyacinth (eichhornia crassipes) has its origins in South America. It was first recorded growing as an ornamental plant in Kenya in 1957. It is a free floating aquatic weed. The plant produces an inflorescence with showy blue/white to violet flowers. Up to 400 minute seeds may be produced from fruiting capsules which develop from the inflorescence. These seeds usually sink and remain dormant in periods of drought; their size allows them to be carried by outflow currents into sewage systems or transferred to other areas where they will grow. However, production is mainly through vegetative propagation and growth is greatly enhanced by high nitrogen, phosphorus and potassium levels.
Water hyacinth can double its mass in as few as 6-15 days. Such is its fertility that it has been estimated that in just under eight months under the right conditions, 10 water hyacinth plants can multiply to 600,000 plants and take over 4000m2 of water. That is more than five times the volume of the sewage lake under discussion.
Compounding the threat, water hyacinth plants can mesh together to form thick floating mats to make travel along infested waterways difficult; the plants also reduce fishing and irrigation to almost nothing. The mats block dams, destroy habitats for birds and fish, and harbor disease-bearing creatures such as certain sorts of snails. One snail in particular is a source of bilharzia, a kidney/liver disease afflicting millions in Africa which produces chronic lethargy and can cause blindness and death.
