River Pollution in the Rio Grande River

Environmental Pollution in the Rio Grande River

The Rio Grande River is known as the river that provides a natural boundary between the United States and Mexico. This river is over 2,000 miles long reaching from the southern Rocky Mountains to the end of Texas. Many people depend on this river as a source of drinking water for them. In the Lower Rio Grande Valley this river receives a lot of agriculture due to all the farmlands and is also used by many people for recreation purposes. Additionally, this river provides a home to much wildlife. Due to an increase in the economic growth and rapid population in the surrounding cities, the Rio Grande has had a tremendous increase in pollution that has caused a negative impact on the surrounding environment. Furthermore, the American Free Trade Agreement (NAFTA) has severely impacted the river causing it now to become the seventh most endangered river in the United States (Flynn 2000). Scientific studies have confirmed that the contamination/pollution of the Rio Grande still poses a problem (Garcia et al. 2001, Berry et al. 1997 a b, Mendoza et al. 2004, Mora et al. 2001, Rios-Arana et al. 2003).

Since these arising circumstances the river endures problems of run-off pollution, discharging of polluted water, over-pumping and the release of millions of gallons of raw sewage by Mexico which clearly defines a present danger to the surrounding environment. Such negative effects have been linked to border health issues and have been attributed to wildlife defects and deaths. For example, in 1994 a young boy’s death was linked to swimming in the Rio Bravo. The cause of his death was traced to an amoeba which was found in the river water that can cause deadly brain infections.

In 1994, the United States and Mexican governments completed a study regarding the presence of toxic substances in the Rio Grande/Rio Bravo between Mexico and the U.S. During a three year period, the U.S. Environmental Protection Agency (EPA) got involved and completed phase two of this study ending in 1997. Results from the study identified an increase in chemical pollution in the river which then led to identifying Laredo, TX as a pollution trouble location (U.S. EPA 2007). The major pollutants observed to have significantly increased over the years in the Rio Grande were heavy metals and pesticides (Garcia et al. 2001, Berry et al. 1997 a b, Mendoza et al. 2004).

In general it seems that some segments of the Rio Grande along the US-Mexico border do pose potential health and/or reproductive harm for wildlife and fish that depend on this river for survival along with the humans that eat fish from those segments (Mora et al. 2001). In 2001, Mora et al. (2001) conducted a study in the Texas, USA-Tamaulipas, Mexico border region to investigate the contamination of pesticides in fish from Texas. Results showed that pesticides were present in fish where concentrations were reported to be significantly greater than data collected during the 1980s and 1990s.

The presence of heavy metals in the Rio Grande has continued even up to the year 2003. In 2003, a study performed by Rios-Arana et al. (2003) confirmed the presence of heavy metals in the water and sediment of the Rio Grande in the area of El-Paso-Juarez. In this study, they found that zinc and lead surpassed the freshwater chronic criteria set by the EPA. Again, this study emphasizes that elevated heavy metal concentrations in the river can post significant harm to the health, survival and reproduction of organisms (Rios-Arana et al. 2003).

Furthermore, in 2004 a study conducted by Mendoza et al. (2007) examined the microbial contamination and chemical toxicity of the Rio Grande for a 112 km segment of the Rio Grande between Fort Hancock, TX and Sunland Park, NM. Their results showed the presence of fecal coliform and E. coli in the river. This study suggests that chemical toxicity applies for most sites along that segment which leads to a concern of water quality in those sections.

However to date, the year 2007, Carlos Rubinstein, Rio Grande watermaster and area director for Texas Commission on Environmental Quality (TCEQ) Region 15, stated that the situation in the Rio Grande is improving. Rubeinstein mentioned We’ve had infrastructure improvements on both sides of the river and those will clearly assist in water quality. He then goes on and says that the rivers water quality is influenced by many elements and that the U.S. can only control part of those elements. Rubeinstein states that wastewater dumping in Mexico, and agricultural runoff still contributes to the pollution problem in the Rio Grande. TCEQ suggests that in the Gulf, dissolved-oxygen levels (water quality parameter) have showed some improvement over the years from 1996 to now (McEver 2007). On the other hand, a study conducted by Buelna and Riffat (2007) suggests that there is still a need for constant monitoring in the Rio Grande in order to keep track of the environmental status since results from their study still showed high levels of contamination.

References

Berry MR, Johnson LS, Jones JW, Rader JI, Kendall DC, Sheldon LS (1997a) Dietary Characterization in a study of human exposure in the Lower Rio Grande Valley: I. Foods and beverages. Environment International 23(5):675-692

Berry MR, Johnson LS, Brenner KP, Thomas KW (1997b) Dietary Characterizations in a study of human exposures in the Lower Rio Grande Valley: II. Household waters. Environment International 23(5):693-703

Buelna G, Riffat R. (2007) Preliminary environmental monitoring of water quality in the Rio Grande in the Laredo-Nuevo Laredo Region. J Environ Sci Health A Tox Hazard Subst Environ Eng. 42 (10):1379-90

Flynn LR, (2000) “Rio Grande No. 7 on List of Endangered Rivers” Laredo Morning Times, April 12, 2000

Garcia SS, Ake C, Clement B, Huebner HJ, Donnelly KC, Shalat SL (2001) Initial results of environmental monitoring in the Texas Rio Grande Valley. Environment International 26:465-474

Hernandez-Romero AH, Tovilla-Hernandez C, Malo EA, Bello-Mendoza R (2004) Water quality and presence of pesticides in a tropical coastal wetland in southern Mexico Marine. Pollution Bulletin 48:1130-1141

McEver M (2007) River water quality report finds some improvements, new trouble spots July 23, 2007. The Monitor Harlingen, TX

Mendoza J, Botsford J, Hernandez J, Montoya A, Saenz R, Valles A, Vazquez A, Alvarez M. (2004). Microbial contamination and chemical toxicity of the Rio Grande. BMC Microbiol. 22:(4):17

Mora MA, Papoulias D, Nava I, Buckler DR (2001) A comparative assessment of contaminants in fish from four resacas of the Texas, USA-Tamaulipas, Mexico border region. Environ Int. 27(1):15-20

United States Environmental Protection agency (U.S. EPA) EPA Region 6 Toxic Substances Study – Questions and Answers, Binational Study Regarding the Presence of Toxic Substances in the Rio Grande/Rio Bravo and Its Tributaries Along the Boundary Between the United States and Mexico. Available [Online]: http://www.epa.gov /region6/water/ ecopro/watershd/monitrng/usmexico/rio_qa.htm. Retrieved Aug. 2, 2007