The natural environment is an important part of urban areas. As a region is developed commercially and its population and infrastructure grow, its natural landscape shrinks (Figure 3.1), the local waterways are altered, and the atmosphere acquires decidedly unnatural characteristics. A panel of speakers described aspects of Houston’s urbanization that are largely responsible for its environmental problems—particularly with regard to air pollution, threats to drinking water supply and quality, and flooding—together with specifics about the impacts of the problems on public health. These individuals also discussed avenues for solutions, both short term and long term.
THE NATURAL ENVIRONMENT AND HUMAN HEALTH
Houston’s corner of Texas is naturally one of the most complex and diverse ecosystems in the world. Although located in the epicenter of a vibrant ecosystem with rolling prairies, lush bayous, hardwood forests and fertile estuaries, little of this natural legacy now remains in the Houston metropolitan area, observed Winifred J. Hamilton, director of the Environmental Health Section of Baylor College of Medicine. Indeed, Houston has an average per-capita land consumption (0.259 acre per resident) that is more than twice that of Los Angeles (0.110 acre) (Kolankiewicz and Beck, 2001), and it has more paved freeway miles (6.1 miles per 1,000 persons) than any other city in the world (U.S. Department of Transportation, 2003).
The impact of increased urbanization and industrialization is evident. The greater metropolitan Houston region contains 406 Toxic Release Inventory (TRI) facilities, 17 toxic-waste incinerators, 16 National Priority List (NPL) Superfund sites, and 85 Superfund sites overall, Hamilton noted (U.S. Environmental Protection Agency, 1998). It is also the location of one of the largest coal-burning power plants in the United States. And the 2.7 million vehicles in this area are driven a total of 125 million miles each day. Per person, she said, area residents drive an average of 39 miles each day—more than any other city in the nation (with 68 miles per person projected for 2025) (U.S. Department of Transportation, 2003; Houston-Galveston Area Council, 2004).
Increased urbanization amplifies exposure to environmental health hazards and is likely to have an adverse effect on human health and well-being. For example, a study of the Los Angeles metropolitan area suggested that each year nearly a thousand new cases of cancer for every one million residents may be caused by exposure to diesel-particulate emissions (South Coast Air Quality Management District, 1999). Other studies have suggested an increased cancer incidence among people who live near refineries (Macdonald, 1976; Pekkanen et al., 1995; Wu et al., 1997), and still other studies have observed that hospital admissions are significantly higher among people who live near major roadways (Buckeridge et al., 2002; Oftedal et al., 2003). These examples suggest that environmental pollutants from many sources are a health concern for the Houston region as well.
Increased urbanization amplifies exposure to environmental health hazards and is likely to have an adverse effect on human health and well-being.
Winifred J. Hamilton
Further, while degradation of the natural environment generally goes hand in hand with increased risks to human health, some individuals—particularly the poor and disenfranchised—are disproportionately exposed to environmental health hazards, noted Hamilton, and may be more susceptible to their adverse
All humans can be adversely affected by air pollution, but the very young … and the elderly … are especially vulnerable.
effects as well. For example, 82 percent of Houston’s waste-management facilities are located in predominantly African-American neighborhoods, even though the black community comprises only about 20 percent of the local population (Bullard, 1983). Similarly, the number of freeways, TRI facilities, and Superfund sites within one mile of Houston elementary schools has a strong inverse correlation with the median income of the neighborhood (Hamilton, 2004, unpublished). Hamilton also noted that among children who live in Houston’s Fifth Ward, a low-income and predominantly black area that is also home to the 36-acre many diversified interests Superfund site, screenings conducted jointly by the Texas Department of Health, the city of Houston and the Agency for Toxic Substances and Disease Registry found that approximately 22 percent of the children have significantly elevated blood lead levels, in comparison with 9 percent of Texas children in general (personal communication, Reyes, 2004).
It doesn’t have to be this way, given the academic, technological, economic, political, and social resources of the region, Hamilton said. Despite the considerable environmental degradation at present, Houston has the potential to be a green and healthy city. For example, an aggressive park and tree-planting program would remove tons of particulates and other pollutants from the city’s air (Nowak, 1994), while at the same time helping to increase community pride and reduce stress and violence. Trees and green space literally and figuratively “cool the streets,” she noted, encouraging civility and calm within urban neighborhoods.
SOMETHING IN THE AIR
The natural environment affects human health not only through the water we drink but also through the air we breathe, and Houston residents (not unlike others who live in urban or industrial regions elsewhere) are exposed to a variety of airborne pollutants that degrade their health by exacerbating already existing conditions or by causing the illnesses in the first place.
Asthma, allergic reactions, and a range of irritant-produced “itis-es” (e.g., rhinitis, sinusitis, conjunctivitis) are among the more routine conditions associated with air pollution, said Stuart Abramson, associate director for clinical research at the Children’s Asthma Center of Texas Children’s Hospital. All humans can be adversely affected by air pollution, he pointed out, but the very young (because of developing organ systems) and the elderly (because of difficulties in recovering from environmental insults) are especially vulnerable.
For example with the criteria air pollutants (airborne compounds that are federally regulated) show that ozone (CO3), sulfur dioxide (SO2), nitrogen diox-
ide (NO2), and particulates all stimulate bronchial reflexes and inflammation, which often manifest themselves in flare-ups of asthma symptoms. These are generally outdoor contaminants, but major air pollution problems result from indoor allergens and irritants as well, especially considering that Americans spend about 90 percent of their time indoors. Indoor agents most highly relevant for the Houston area include dust mites, mold, pet-derived allergens, air fresheners, cigarette smoke, and cleaning solvents. Studies in Houston schools to measure children’s exposures to dust mites and mold, Abramson reported, showed that 30 to 50 percent of the classrooms exceeded thresholds for sensitization (Tortolero, et al., 2002).
Abramson stressed, however, that studying one contaminant at a time gives an erroneous, and usually understated, expression of the effects of air pollution on human health. Studies may report one health effect from ozone and another health effect from a different contaminant, but few studies have looked at contaminants together or at the combined impacts of indoor and outdoor environments with regard to personal exposures.
Some of the net effects are that asthma incidence among the nation’s children has doubled in the past decade—about 6 million children have this disease, as do 20 million Americans overall. In Houston, a study done with the collaborative efforts of the Children’s Asthma Center, the University of Texas School of Public Health, and Baylor College of Medicine surveyed some 21,000 city schoolchildren and found that about 10 percent of them had asthma (Sockrider et al., 1999; Tortolero et al., 2004).
In a 151-city study, in which Houston was included, researchers found a 4 percent increase in overall mortality, a 6 percent increase in cardiovascular mortality, and an 8 percent increase in lung cancer mortality related to particulates, which tend to be composites of numerous compounds (Pope et al., 2002). In an older, but seminal, 6-city study in which Houston was not included, overall mortality was 26 percent higher in the most polluted city of Steubenville, Ohio (Dockery et al., 1993).
Despite the extensive indications (the above represent a small sample of the results of numerous studies), direct correlations between adverse health effects and specific air pollutant exposures are difficult to come by—the obligatory epidemiologic studies require a financial commitment, extensive population, and very critical assessment of different confounding variables, noted Abramson. This gap is particularly acute in Houston, where anecdotal connections are persuasive but actual epidemiologic evidence is rare.
Still, efforts to correct the omission are under way. An assessment of information needs for research on air pollution health effects in this area was recently put together by BRIDGES to Sustainability and the Mickey Leland National Urban Air Toxics Research Center funded by the Texas Council on Environmental Technology (BRIDGES, 2003). The city of Houston has received a Health Tracking Grant from the Centers for Disease Control and Prevention and
With the aid of federal legislation, the region had made significant progress over the past few decades in cleaning up its water pollution, hazardous waste disposal sites, and even some of its air pollution, although there is still substantial room for further improvement.
it is currently considering particular health effects on which to focus. Asthma is being studied through a project funded by The Robert Wood Johnson Foundation and the American Academy of Allergy, Asthma, and Immunology that is looking at emergency room admissions of children at the Houston area hospitals that account for the 80 percent of all pediatric admissions. Lastly, Texas Children’s Hospital is participating in a study sponsored by the Mickey Leland Center to look at all of the region’s schoolchildren and their personal exposures to a variety of aldehydes, ketones, and other air pollutants. The ultimate goals of these efforts, said Abramson, are better environmental controls and conservation measures to help reduce the amount of exposure.
Learning from Water Pollution While Addressing Air Pollution
Environmental degradation, even in its more extreme forms, need not be permanent when motivated people, empowered by effective laws and policies, are persistent. Environmental attorney James Blackburn, a principal in the Houston firm of Blackburn & Carter, noted in particular that with the aid of federal legislation, the region had made significant progress over the past few decades in cleaning up its water pollution, hazardous waste disposal sites, and even some of its air pollution, although there is still substantial room for further improvement.
In the 1970s, some environmentalists dubbed the Houston Ship Channel the most polluted waterway in the United States and probably the world. However, there were significant improvements in the cleanup of the waterway and Galveston Bay (to which it connects) when the Environmental Protection Agency (EPA) enforced the Clean Water Act of 1972. That law, said Blackburn, was strong and effective, requiring a permit for all existing water pollution point sources (Figure 3.2). The result was a significant improvement in wastewater treatment systems, which mean that water quality has improved.
Similarly, the federal government has played a critical role in addressing the industrial pollution associated with solid and hazardous wastes in the Houston area, according to Blackburn. CERCLA (the Comprehensive Environmental Response, Compensation, and Liability Act)—commonly known as the Superfund Act—has been instrumental in addressing the surface manifestations of hazardous wastes. It is effective, and has resulted in Houston’s hazardous waste sites being cleaned up. One might still find a 55-gallon drum somewhere, but for the most part the city has disposed of the surface manifestations. Also, although
contamination of the soil and of the shallow groundwater beneath the soil is a remaining problem, this is not considered a threat to drinking water because the area has a clay layer that limits much of the chemicals’ downward movement.
Another example of effective federal involvement in improving Houston’s environmental quality involves air pollution. There has been a significant improvement in cleaning up the region’s ozone pollution since 1970, when the Clean Air Act was passed and EPA acquired jurisdiction over, the clean up, said Blackburn. The ozone pollution levels went from approximatley 400 parts per billion down to approximately 200. However, the federal standard is 120 so there are still significant violations; Houston has failed to meet the standard for more than 30 years and there has been a history of not being as concerned about health issues as is warranted, cautioned Blackburn.
Strategies for Addressing Air Pollution
Some approaches for addressing air pollution were offered by Ramón Alvarez, a scientist in the Texas Office of Environmental Defense. For example, trucks that are lower emitting and more fuel efficient (and therefore lower cost over the life of the vehicle) should be deployed wherever possible. FedEx is
developing such trucks for its package deliveries, and Houston’s air could benefit from them in the near future.
Another way to reduce an important emissions source from diesel vehicles—the extended idling of long-haul diesel trucks at roadside truck stops which is mainly done for heating or cooling—could be eliminated by using electric-powered services (including temperature control, telephone, internet, and cable) that attach to the window of the truck cab. This technology’s general use would not only eliminate unnecessary pollutant emissions (which sometimes persist as long as 12 hours at a time), but also save truckers money on fuel costs and wear and tear on their engines, noted Alvarez (Figure 3.3).
For reducing transportation-related emissions more generally—from cars as well as trucks—Alvarez pointed out the need to focus on the demand side and give people incentives to drive fewer miles. One such approach being promoted by Environmental Defense is “pay-as-you-drive” car insurance policies in which premiums are priced by the number of miles driven rather than at a fixed annual rate. Another is “parking cash out,” whereby businesses offer employees the option of taking the cash equivalent of parking space fees in exchange for finding alternative ways to get to work.
Longer-term solutions clearly are needed, Alvarez said, and they tend to be
supply side. He suggested that the region should be increasing the pedestrian, bike, and transit options for everyone and emphasizing smart growth in the development of communities. For example, in the Dallas suburb of Frisco, new homes must be built to a high level of energy efficiency in accordance with EPA’s Energy Star building standard, which reduces electricity consumption by 30 percent compared to a standard home. This not only decreases costs to homeowners over time but also reduces emissions from power plants, thus alleviating regional air pollution and global warming.
Also over the long term, he added, we need to focus on reducing industrial emissions, promoting environmental accountability, and educating legislators about the public health implications of their decisions. The public support for strong clean air measures was borne out by a recent survey of local residents (Klinenberg, 2002). The most critical challenge facing Houston, in respondents’ opinions, was traffic. Environment was second—ranking ahead of economy, crime, and schools—and, within environment; the issue of air quality and its connection to health was listed as top priority.
Citing Dr. Goldman’s earlier remarks about the counterproductive nature of finger pointing, Alvarez urged that the air pollution problem be approached holistically. The region’s air will not be cleaned up merely by focusing on one source category, whether vehicle emissions or industrial emissions. If the region emphasizes one over the other, it runs the risk of harming the entire effort. The region must address all of the sources, he noted.
REGIONAL FLOODS: CONTINUAL CHALLENGES
Most of Texas has a water supply problem: its communities tend to be chronically short of water. Yet Houston’s corner of the Gulf Coast—characterized by frequent thunderstorms and hurricanes, coupled with the flatness of the local terrain and large flood plains—is episodically stressed with an abundance of water. Kevin Shanley, president of the SWA Group (a national landscape architecture firm) and president of Houston’s Bayou Preservation Association, noted that too often when it rains in Houston, Houstonians don’t know what to do with all the water. The resulting floods can be costly and severe as they disrupt local transportation systems, businesses, and daily life in general; put entire neighborhoods under water; and invade homes and automobiles. Tropical Storm Allison of 2001, for example, inundated 70,000 local homes and hundreds of thousands of cars and the basement of the Texas Medical Center.
Meanwhile, shallow wells and drinking water treatment plants get contaminated by run-off, the power system is disrupted, and many industrial operations grind to a halt. Financial impacts can be prodigious: Allison alone caused $5 billion in damages just for readily quantifiable losses. Even in quieter times, the cost of insurance for flooding poses a major economic burden to the Houston community, particularly lower-income neighborhoods.
Flooding also presents numerous risks to human safety and health. Street flooding leads to traffic accidents and drowning, people needing medical care may be isolated (or medical centers themselves be rendered inaccessible), and the mosquito population rises, which leads to increased disease risk. With sewage systems grossly overloaded, sewage comes out of manholes and out of people’s properties, spewing untreated wastes across the landscape. Rising water lifts toxic materials out of the ground, making contact with humans more likely.
Such devastation, risk, and uncertainty can wreak havoc not only on the community’s property, processes, and physical health but also on its spirit. Houstonians are such resilient people that even when their personal possessions are put out on the street or swept away, they rebuild, but Shanley questioned what all of this means in terms of our social fabric.
It is logical that given the long history of flooding events in this region and their vast impacts, Houstonians are now working on solutions to prevent their occurrence—or at least limit their magnitude—in the future. One set of options aims to establish better drainage systems, noted Shanley. This consists of networks of bigger and bigger collection pipes that lead to ditches and then to larger ditches. It is a very efficient process, but with a major drawback. Unlike rain in a natural watershed, where water accumulates in a stream and has considerable time to leave the watershed, these efficient drainage systems collect the rain into channels quickly, resulting in a spike in the water level (Figure 3.4), he said. Water levels may subside quickly, but it really doesn’t matter whether the water was in the basement of a hospital for 10 minutes, or 2 hours, or 12 hours, the water damage is done, observed Shanley.
Another set of options involves peak flow attenuation, which is designed to eliminate the spike in water runoff. This has to occur on the individual property as well as on the regional level. Whether one is a businessman, property developer, or homeowner, one needs to keep the rainfall that lands on their property confined to the property for as long as possible, said Shanley. Such retention can transcend individual solutions and grow in scale—and enjoy economies of scale. Right now in fact, regional authorities are planning and implementing large regional retention basins, he noted. These larger retention basins are part of the solution, but they cannot be the only solution, because smaller systems of different types of water management provide complementary support.
In this spirit, Shanley briefly discussed the options of dispersed systems such as drainage schemes in parking lots that feed subsurface containments, home cisterns that accumulate roof runoff, and street medians and rain gardens that not only store water but provide rich and beautiful ecological zones (Figure 3.5). Not to be overlooked on this score are the region’s own natural (or augmented) wetlands, which are the big sponges of the area.
PROVIDING SAFE DRINKING WATER
Safe drinking water is the first line of defense in protecting public health from environmental threats. The provision of drinking water, of high quality and in adequate quantities, is the main mission universally shared by the nation’s water supply professionals, noted Roger Hulbert, senior assistant director of water production for the City of Houston.
Federal authorities currently regulate 87 different contaminants in drinking water, require monitoring of (but do not regulate) an additional 26 compounds, and have established 15 secondary standards for aesthetic water quality measures such as taste and odor. Hulbert stressed that the city of Houston, together with most other public water utilities in the United States, complies with these regulatory standards. He noted, for example, that in 2002 alone, Houston conducted some 427,000 chemical, microbiological, and physical analyses of water in reservoirs, treated water, and distribution system water to confirm that fact; the city actually exceeds the requirements of EPA and the Texas Commission on Environmental Quality, Hulbert said.
With respect to quantity, the city has 1.1 billion gallons of water supply capacity—a wealth of water that enables it to be a regional provider to the eight-county area’s water utilities. The city has planned not only for water rights to ensure supply, but also for adequate treatment capacity. It currently boasts 510 million gallons per day of capacity for surface water treatment and expects an additional 120 million to be online by about 2008. Also available are some 360 million gallons of groundwater, but Hulbert noted that Houston area authorities are moving away from dependence on this resource. Reasons include the natural arsenic concentrations in some local groundwater and subsidence caused by the mining of groundwater.
He cited the adage that everybody lives downstream from somebody else—and that Houston actually lives downstream from Dallas. A significant part of the Trinity River’s flow at times is wastewater from Dallas, and even though it then meanders hundreds of miles and goes through the Lake Livingston Reservoir—thereby receiving natural filtration before arriving in Houston—the city nevertheless has to finish the water at its surface-water treatment plants.
Local wastewater, meanwhile, may soon serve as a water supply resource in its own right and give water conservation efforts a boost. The city is conducting a water reclamation feasibility study now, based on membrane treatment of wastewater effluent, for a capacity of up to 100 million gallons a day for industrial water uses along the Houston Ship Channel. If this approach proves feasible, the cost of distributing such water to industrial customers, who would then use it for production processes and cooling, would be much reduced. A
A gallon saved is a gallon that does not have to be treated to drinking water standards.
gallon saved is a gallon that does not have to be treated to drinking water standards, according to Hubert.
LEARNING FROM NATURE
Speakers during the session on the natural environment noted the need for long-term solutions. One way would be to develop a grassroots base, think holistically in addressing environmental problems, and build greener and healthier cities, asserted Cath Conlon, founder and director of the Blackwood Educational Land Institute (Hempstead, Texas), and her colleague Jackie Hall of the Hall Group, a business development consultancy. Blackwood Educational Land Institute may bridge the gaps by providing a “living classroom” for teaching children and adults alike to explore the natural web of life and develop a healthy relationship with nature—or, according to the institute’s mission statement, “a reverence for and accountability to nature.” Forming such bonds between the environment and people, suggested Conlon and Hall, helps strengthen our communities—urban and otherwise—as well.
Forming such bonds between the environment and people helps strengthen our communities—urban and otherwise—as well.
Cath Conlon and Jackie Hall
Blackwood offers school curricula, workshops, retreats, and seminars to Houstonians (the 23-acre tract is located some 45 minutes from the city), based on the belief that the land is the true teacher. When children experience nature so directly, said Hall, they can then become ecologists. They appreciate conservation and become more aware of their surroundings. Also, although most of the city kids who learn at Blackwood don’t have so much as a postage stamp of land of their own, the important thing is the state of mind they have acquired—likely, for a lifetime—about their environment, wherever and whatever it may be.
This learning is not a one-time-only affair. Consistent with its message of sustainability, Blackwood establishes relationships with students, usually when they are in middle school that last throughout their high school years. By the time they graduate, they have spent 150 days at Blackwood. The resulting legacy not only elevates environmental awareness in general but cultivates a child’s own health and well-being, on into adulthood, by having profited from such practical lessons as good nutrition at the institute, said Conlon. This consciousness in interconnectedness and sustainability, Conlon suggested, may also promote preventive measures for many of the diseases and conditions bemoaned by earlier speakers—asthma, diabetes, cancer, obesity, depression—that are caused or exacerbated by degraded environments.