By Maeggi Hieber , El-Salvador

Cérron Grande is El Salvador’s largest body of fresh water and the biggest of its Ramsar Sites, wetlands of international importance. At the same time, the reservoir is known to be one of the most contaminated bodies of fresh water in Central America. An actual investigation demonstrated its high levels of contamination and the manifold sources of pollution. Heavy metals, banned insecticides, cyanides, fecal bacteria, and toxic algae affect the health of humans and animals. A monthly load of more than 8.5 millions pounds of feces cause frequent algal blooms and the eutrophication of the reservoir. Actions have to be taken on all levels to prevent further contamination and treat the existing pollution. Local organizations such as Pro-Vida are working in the country side with the local population implementing actions on regional as well as governmental level to improve quality of life.

Cérron Grande is El Salvador’s largest body of fresh water and the biggest of its three Ramsar Sites, wetlands of international importance [1]. Cérron Grande, locally known as Suchitlán Lake, is a reservoir constructed in 1973 to serve the hydroelectric power plant. This outstanding man-made wetland of 607 square kilometers forms an important habitat for different endangered and endemic species and an unique staging and breeding area for migratory and resident water birds [2].  The reservoir Cérron Grande forms part of the tri-national watershed of the river Lempa, originating in Guatemala, passing through Honduras, continuing its course for another 360 km in El Salvador until it reaches the Pacific Ocean. Although only 49% of El Salvador’s territory is covered by the Lempa river basin, 77% of the Salvadoran population lives in cities, towns, and villages that are located in its basin, including the capital city of San Salvador. Besides, the reservoir plays a major role in purification of the water and control of flooding.

In spite of its environmental and economic importance, the Cérron Grande today is one of the most contaminated bodies of fresh water in Central America. An actual investigation realized by the Salvadoran Association of Human Aid Pro-Vida and financed by Oxfam America demonstrated its high levels of contamination and the manifold sources of pollution. Bacteria, heavy metals, pesticides as well as other chemical parameters in the Cérron Grande exceeded the respective water quality standards. [3]

Total coliforms, a bacterial group indicating fecal contamination, showed concentration of more than 10’000 colonies in 100 ml thereby not only exceeding by far the desired range for surface waters but also the maximum concentration allowed for waste water being discharged in receiving water. Another biological group unwanted in surface waters are some blue-green algae, a group of cyanobacteria famous for their ability to produce natural toxins dangerous to humans and animals. The mass-reproduction of cyanobacteria called algal blooms is visible by a bright green discoloration of the water and can cause negative impacts to other organisms via production of the harmful toxins. Although algae and cyanobacteria are natural components, their mass-reproduction is the result of increased nutrient loading from human activities

Fig. 1: Algal bloom in the reservoir Cérron Grande, El Salvador (Photo: M. Hieber)
Fig. 1: Algal bloom in the reservoir Cérron Grande, El Salvador (Photo: M. Hieber)

Sources of increased nutrient load usually are untreated waste waters discharging the nutrient rich feces and urine into surface waters. It is estimated that the reservoir Cérron Grande receives a monthly load of more than 8.5 millions pounds (4 million kilograms) of feces deriving from 1.5 million households of the capital San Salvador. Increased nutrient load not only benefits the growth of algae and cyanobacteria but also causes eutrophication of standing water bodies. In its 37 years of existence, the reservoir changed to a hypereutrophic lake promoting by its high nutrient concentrations excessive plant growth and decay, thereby causing anoxia (lack of oxygen in the water) and severe reductions in water quality, fish, and other animal populations.

The rivers Suquiapa, Sucio and Acelhuate, forming 30 % of the flow entering the reservoir, are draining the untreated sewage and wastewater effluent from at least 154 municipal and industrial sources from the metropolitan area of San Salvador. Elevated concentrations of heavy metals such as cadmium, mercury, copper and aluminium were found in the water as well as in different water plants and fishes. Heavy metals are accumulating in the organisms and, therefore, concentrating along the food chain. The last link in the food chain, such as humans, receives the highest concentration of the toxic substances. [4]

Dieldrin and Cyanide are two other toxic substances able to accumulate along the food chain which were found in the water of the Cérron Grande. The insecticide Dieldrin is one of the “PAN Dirty Dozen Pesticides”, extremely hazardous pesticides that cause many deaths and widespread environmental damage every year. Although most have been banned or restricted in the industrialized countries, yet the Dirty Dozen still is heavily promoted and widely used in many developing nations. [5] In El Salvador, registration, importation, exportation, fabrication, commercialization and distribution of Dieldrin was officially prohibited in 2000 – but not its use which still is very common. [6]

Cyanide is mainly used for the mining of gold and silver. Cyanide compounds that can release the cyanide ion CN_ are highly toxic and have been used as poison many times throughout history, for example as Zyklon B by the Nazi regime in Germany for mass murder in some gas chambers during the Holocaust. El Salvador is a country rich of gold and silver. Approximately 12 million ounces of gold and 78 million ounces of silver are available for exploitation. It is estimated that the mining of these resources would require the daily application of 950 tonnes of cyanide and some 22 million liters of water. [7] To this date, the Salvadoran government still has not given authorization to the exploitation of gold or silver and the future situation remains open. However, in the neighboring countries of El Salvador several mining projects already exist. The project Cerro Blanco situated in Asunción Mita, Guatemala closed its exploration phase and probably will start its exploitation of gold in 2010. [8] Cerro Blanco is about 20 km from the salvadoran border and part of the watershed of the reservoir Cérron Grande. Although there is no evidence that the cyanide found in the samples of the Cérron Grande comes from the project Cerro Blanco, there is a great risk of contamination of the water and environment by the different mining projects in El Salvador and its neighboring countries.

This study of the water quality of the largest waterbody in El Salvador is just one example of the drastic situation of water quality in the whole country. The national diagnostic of surface water quality carried out by the National Service of Territorial Studies (SNET) showed that only 20 % of the national rivers are suitable for the abstraction of drinking water, 24 % for irrigation, 14 % for recreative use in contact with humans and only 17 % were qualified as “good” thus allowing the development of aquatic life without any limitations. [9] But still only few data exist. The national monitoring is restricted to rivers and basic physical, chemical and biological parameters. Hardly any information exist about the quality of standing water bodies and even less about contamination of other chemical parameters such as heavy metals, pesticides or cyanide.

The causes for the bad quality of (surface) waters are manifold. Primarily, there is a high level of contamination due to the lack of waste water treatment. In 2008, only 1 % of the rural and 57 % of the urban population were connected to a sewage system. [10] Industrial waste waters also generally discharge directly into surface waters without any treatment. Reason for this not only is a lack of legal regulations but also of control and observing the existing laws. Besides, the existing regulations hardly have any maxima or recommended water quality criteria for surface waters. Without maxima values also doesn’t exist a contamination. And the threat to the environment posed by the mining projects could worsen the situation drastically. Water analyses of surface waters close to the gold mine San Martin en the Siri Valley, Honduras, resulted in almost all parameters above recommended water quality criteria for waters discharging from mines, such as cyanide, arsenic, lead, chromium, mercury, cupper, zinc and aluminium. Most of these heavy metals are accumulating in the food chain thus causing cancer and abnormalities of physiological development. Some of these contaminants also were found in the drinking water of wells close to the mine. [11]

Solving these problems is not an easy task. Measures have to be taken on all levels, from individuals up to international actions, to prevent further contamination and treat the existing pollution. There is big necessity to create awareness and sensitize the local population on sanitation, use of agrochemicals and protection of the environment and their water resources. Local organizations have to be strengthened, waster water treatment plants installed, quality of drinking and surface water monitored, observation of the existing laws controlled, the legal situation improved and maxima values implemented, and international agreements on transboundary watershed protection established.

Local organizations such as the Salvadoran Association of Human Aid Pro-Vida are focusing on working in the country side with the local population to help create awareness and sensitize the local population, strengthen local organizations and implement measures on regional as well as government level and, therefore, improve water quality and the quality of life.


I especially would like to thank INTERTEAM, a Swiss organization of Personnel Development Co-operation [12], for giving me the opportunity to experience and live in this country and work with the Salvadoran NGO Pro-Vida as well as to my colleagues of Pro-Vida for welcoming and supporting me. All projects are possible thanks to the support and assistance of our international partner organizations such as Oxfam America, Solidaridad International, Swiss Labor Assistance, Technical Cooperation Frank A. Escher, Swiss Solidarity, Georg Fischer Foundation “Clean Water”, ANESVAD, Elkartasuna and Intersol.

Further information: http://www.interteam.ch/einsaetze/fachleute.htm

[1] http://ramsar.wetlands.org/
[2] MARN/AECI. 2004. Ficha Informativa de los Humedales de Ramsar. El Salvador.
[3] Mäggi Hieber. 2009. Reporte del Estudio del Analyses de la Contaminación del Cérron Grande. El Salvador
[4] CEL / HARZA Engineering Company International L. P. 1999. Estudio Global de la Sedimentación en la Cuenca Del Rió Lempa, Apéndice C Estudio Ambiental. El Salvador.
[5] http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC33416
[6] Acuerdo Ejecutivo No. 151 de fecha 27 de junio de 2000, por parte del Ministerio de Agricultura y Ganadería, publicado en la pág. 57 de La Prensa Gráfica del 19 de julio de 2000
[7] Florian Erzinger et al. 2008. El lado oscuro del oro. Impactos de la minería metálica en El Salvador. El Salvador.
[8] http://www.goldcorpguatemala.com
[9] SNET. 2007. Diagnóstico Nacional de Calidad de Aguas Superficiales. El Salvador.
[10] Ministerio de Economia, Direccion General de Estadistica y Censos. 2008. Encuesta de hogares de propositos multiples. El Salvador.
[11] Florian Erzinger et al. 2008. El lado oscuro del oro. Impactos de la minería metálica en El Salvador. El Salvador.
[12] http://www.interteam.ch

The author

Maeggi Hieber
Contact: maeggi.hieber@interteam.ch


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