Rapid industrialization and population growth in the U.S.-Mexico border region, stimulated in part by NAFTA, is requiring a greater need to understand environmental health trends. Like many public health challenges, pollution and contamination do not respect territorial borders. Environmental contaminants on one side of the border can easily affect the air, water, soil, fauna, and flora on the ... other side. Hazardous materials and wastes, pesticides, nitrates, untreated sewage and wastewater, parasites, and bacteria, if not handled properly, can endanger the environment in which we live. In certain areas the interrelationships between environmental conditions and human health are well documented. However much is still not known about this complex relationship and needs to be explored to resolve environmental health problems.
Environmental health issues in the U.S.-Mexico border region pose two primary challenges. The first, as noted by the Good Neighbor Environmental Board, is a combination of what the World Health Organization (WHO) identifies as .traditional' and .modern' hazards (GNEB, 1995). Traditional hazards are risk factors associated with poverty and the lack of infrastructure in a region, whereas modern hazards are related to rapid development, consumption patterns and unsustainable development (WHO, Health and Environment in Sustainable Development, 1998). The links between traditional hazards and health risks can be seen quite clearly in the colonias. Colonias are communities along the U.S.-Mexico border, largely on the U.S. side, that frequently suffer from inadequate housing (typically non-permanent structures), poor or nonexistent infrastructure, and lack of basic services. For example, the colonias lack adequate access to safe drinking water; they often have inadequate sanitation in the household; residents suffer from indoor air pollution due to cheap fuels used to cook and heat their home; and the communities generally have deficient solid waste disposal. The second, more complex challenge is the binational nature of environmental issues on the border. It is not sufficient to approach and resolve environmental health problems unilaterally. Sustainable solutions must involve binational cooperation.
Water pollution is a primary concern of border communities (Bruhn, J.G. & Brandon, J.E., 1997). Existing public infrastructures including water systems, sewerage systems, and solid waste and wastewater treatment facilities, have been unable to sustain the rapidly growing border populations. Consequently, the border residents are likely to be exposed to untreated and contaminated water, thereby increasing their risk of adverse health effects and disease. Thirteen percent of the population living in colonias in Texas are reported to be without adequate plumbing, compared to the national average of five percent (Bruhn, J.G. & Brandon, J.E., 1997). The increasing number of maquiladoras also strains existing wastewater and solid waste infrastructures, particularly with regard to industrial wastes.
Water pollution and contamination are present on both sides of the border. For example, the New River, which flows northward from Mexico through Imperial county, California, is considered by some to be the most polluted river in the United States. Reportedly, 130 million gallons of agricultural runoff, industrial waste and untreated and/or partially treated sewage flow daily into the river (San Diego Union-Tribune, 5/5/97; USEPA New River Project Summary). Though not as large an amount, an estimated 12 million gallons of raw sewage was dumped daily into the Tijuana River during 1990. The river flows northward from Mexico to the United States and into the Pacific Ocean. Similarly, 27 million gallons of untreated wastewater in Nuevo Laredo are discharged into the Rio Grande/Rio Bravo del Norte (Bruhn, J.G. & Brandon, J.E., 1997).
Air pollution is another complex, binational challenge facing the border populations (Bruhn, J.G. & Brandon, J.E., 1997). According to a study by English, et al., high childhood asthma rates are likely due to a worsening of air quality conditions produced by increased pollutant burdens on the local airshed. In 1990, it was noted that Imperial County, California had the highest childhood asthma hospitalization rate for non-Hispanic whites and African-Americans, and the second highest for Hispanics (English and Von Behren).
During the colder months, air quality in the El Paso-Ciudad Ju?rez airshed worsens from a variety of sources. As many border residents live in substandard housing, they use whatever fuels they can obtain to keep their homes warm. Generally, these materials are of poor quality, such as sawdust or scrap wood that may have been chemically treated. As a result, the pollutant laden smoke produced from these fuels contributes to the overall air pollution levels and is more likely to have adverse health effects on children. Other contributors to the poor air quality in the region include vehicular exhaust at congested international crossing points, unpaved roads, open fires and the effluent from many of the industrial plants in the vicinity (Blackman and Bannister, 1998).
The effect of environmental contaminants on children must be emphasized. Children are more susceptible than adults to environmental pollutants because their organ systems are still developing, and the higher likelihood of contaminant intake due to their hand-to-mouth activities. In addition, children also breathe with greater frequency and consume food and liquids more frequently than do adults (Bruhn, J.G. & Brandon, J.E., 1997), thus increasing their pollutant intake. Of particular concern for families residing in the border area are pediatric exposures to lead and pesticides because of the multiple ways in which children may be exposed.
Pediatric lead exposure in the U.S.-Mexico border region results from three primary pathways. The first is exposure to lead-based paints from old doors and furniture that have been exported to Mexico. The second pathway of lead exposure is from food or drink contaminated by lead glazed pottery produced in central Mexico. The last pathway of exposure is from lead in the soil from industries such as smelters and battery recycling plants.
Children living in the U.S.-Mexico border area may also be exposed to pesticides generally through two principle pathways. These include pesticide residue on their food and pesticides sprayed on fields near homes and schools. In addition, there is also a growing concern regarding the proper use and storage of household pesticides.
The complexity of these environmental health concerns in the U.S.-Mexico border region requires a coordinated, binational approach at all levels of government. Unilateral efforts, no matter how well intentioned, will fall short in their attempts to address these concerns because communities on both sides of the border share the same environment.
Environmental Health Workgroup initiatives include Pesticide Exposure and Health Effects on Children, Pediatric Lead Exposure Identification and Risk Reduction, Neural Tube Deffects Assessment, Health Alerts and Communication, Toxicology Center Development, and Geographic Information Systems.