Water hyacinth ''Pontederia crassipes'' (formerly ''Eichhornia crassipes''), commonly known as common water hyacinth is an aquatic plant native to South America, naturalized throughout the world, and often invasive outside its native range.invasive plant species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

Lake Victoria Lake Victoria is one of the African Great Lakes. With a surface area of approximately , Lake Victoria is Africa's largest lake by area, the world's largest tropical lake, and the world's second-largest fresh water lake by surface area after ...

and while it is native to the continent of South America, human activity has introduced the greenery to Lake Victoria, where it is claimed to have negatively affected local ecosystems.

History

The exact time and place of introduction has been debated, but the plant is native to South America so it appears to have reached Lake Victoria due to human activity. As its flowers are reputed for their beauty, it might have been brought over as an ornamental for garden ponds by Belgian colonists in Rwanda and Burundi.United Nations News Highlights, "Fighting water weeds in West Africa." Food and Agriculture Organization of the United Nations. 16Aug2000. United Nations. 19 May 200

/ref> The consensus is that water hyacinth entered Lake Victoria from Rwanda via the river Kagera, probably in the 1980s. The hyacinth has since spread prolifically, due to a lack of natural predators, an abundance of space, agreeable temperature conditions, and abundant nutrients, including increasing heavy metal pollution in the lake.Opande, G.O., Onyang, J.C., Wagai, S.O.. "Lake Victoria: The water hyacinth (Eichhornia crassipes ART.SOLMS),its socio-economic effects, control measures and resurgence in the Winam gulf." Limnologica 34. 1-2 May2004 105-109.Journal of Industrial Pollution Control, "Water Hyacinth and Duckweed as indicators of heavy metal pollution in River Asa." 29(2)(2013) pp 155-16

/ref> Water hyacinths increased rapidly between 1992–1998, were greatly reduced by 2001, and have since resurged to a lesser degree. Management techniques include (hyacinth-eating) insect controls and manual beach cleanup efforts. A water hyacinth infestation is seldom totally eradicated. Instead, it is a situation that must be continually managed.World Bank. 1996
Kenya, Tanzania, Uganda - Lake Victoria Environmental Management Project
World Development Sources, WDS 1996. Washington, DC: World Bank.

Development

Water hyacinth affects the Lake Victorian population in many negative ways. There are economic impacts when the weed blocks boat access. The effects on transportation and fishing are immediately felt. Where the weed is prolific, there is a general increase in several diseases, as the weed creates excellent breeding areas for

mosquitoe Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "lit ...

s and other insects. There are increased incidents of skin rash, cough,

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

encephalitis Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...

, gastro-intestinal disorders, and bilharzia/

schistosomiasis Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, bloody s ...

. Water hyacinth also interferes with water treatment, irrigation, and

water supply Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Thes ...

. It can smother aquatic life by deoxygenating the water, and it reduces nutrients for young fish in sheltered bays. It has blocked supply intakes for the hydroelectric plant, interrupting electrical power for entire cities. The weed also interrupts local subsistence fishing, blocking access to the beaches. There are also indications that water hyacinths can provide benefits to the Lake Victoria Region.V.A. Valk, MSc thesis, Geoscience and Engineering, Delft University of Technology "Valorization of water hyacinth as a renewable source of animal feed and biogas: a business case for Lake Victoria, Kenya" 2015-02-0

/ref> Water hyacinths have been planted in an attempt to Eutrophication#Prevention, purify eutrophicated water.Huan Jing Ke Xue. " Purification effects of large-area planting water hyacinth on water environment of Zhushan Bay, Lake Taihu" 2011 May;32(5):1299-30

/ref> Once established, the plants can be harvested and used for biogas production,International Journal of Engineering and Technology "Feasibility Study of Biogas Production from Water Hyacinth A Case of Lake Chivero – Harare, Zimbabwe" Volume 3 No. 2, February, 201

/ref> fertilizer, and other things.Waste Manag Res "Production of Feed and Fertilizer From Water Hyacinth Plants in the Tropics" January 1994 vol. 12 no. 1 3-1

/ref> In 2018 two

biogas digester Biogas is a mixture of gases, primarily consisting of methane, carbon dioxide and hydrogen sulphide, produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste and food waste. It is a re ...

s were installed in the village of Dunga in Kenya, with many more slated to be installed in Kenya.Kenya warms to the water hyacinth as wonder source of biofuel
theguardian.com, 27 August 2019

References

{{commons, Eichhornia_crassipes, Water hyacinth Environment of Africa Lake Victoria Pontederiaceae Invasive plant species by region