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   A step forward on cumulative impacts - March 2011


The Networker
I. I. Editor's note: After 11 years Nancy Myers
II. A screening method to compare cumulative impacts among communities
California Environmental Protection Agency
II. III. Health disparities, socioeconomic factors, and their relationship to pollutant-related diseases
California Environmental Protection Agency


  I. Editor's note: After 11 years   TOP
 By Nancy Myers

Environmental justice advocates have long pointed out the obvious: polluting industries tend to concentrate in poor communities, adding to social, economic, and other hardships already suffered by residents of these communities. All the stresses compound and contribute to significant health disparities between poorer and wealthier communities. The importance of "cumulative impacts," as Sierra Crane-Murdoch writes in a fine introduction to the concept in the March 10 High Country News, has become conventional wisdom in public health circles and suffering communities.

A California law enacted in 2000 gave the state’s environmental protection agency (CalEPA) responsibility for remediating environmental injustice. It defines environmental justice as "the fair treatment of people of all races, cultures, and incomes with respect to the development, adoption, implementation, and enforcement of environmental laws and policies."

Environmental justice advocates were quick to see the need for the precautionary principle--which shines a light of prevention through the smog of harm resulting from multiple factors--to address the problem of cumulative impacts. So when CalEPA was writing an action plan to carry out the environmental justice mandate, advocates saw to it that the plan included a promise to develop guidance not only on cumulative impacts analysis but also on precautionary approaches that would reduce cumulative impacts. The action plan was published in 2004.

Now, 11 years after the environmental justice law was enacted, one part of one of the most challenging steps of its implementation has been laid out in a report, Cumulative Impacts, Building a Scientific Foundation. The wheels of legislation turn slowly indeed. And yet California is still, as Carolyn Raffensperger wrote in 2005, leading the way on cumulative impacts policy. Building new policy from the ground up is a monumental task.

SEHN has been involved in much of this process since 2005 but any real progress is due to the determination, persistence, and patience of environmental justice organizations and advocates in the state. Their efforts in marshalling academic, scientific, legal, and political alliances to this task have been truly heroic.

We present two excerpts of the CalEPA report, which introduces a scientific method to compare cumulative impacts in communities. The first excerpt explains the need to address cumulative impacts and introduces the comparison method. The second presents an overview of health disparities in vulnerable populations, focusing on diseases in which environmental factors are likely to play a role.

CalEPA's Office of Environmental Health Hazard Assessment (OEHHA) issued the report for public comment last fall and published it in final form on schedule, December 31, largely unchanged despite rumors that polluting industries were pressuring for substantial last-minute changes. One addition to the final report was a prominent disclaimer up front emphasizing that it "is not a regulatory action and does not have the force or effect of a regulation" and that any implementation or use of the screening method by CalEPA would have to await the development of further guidelines.

Also still to come is any attempt on the part of CalEPA to develop the promised "precautionary approaches" to alleviate cumulative impacts.

SEHN Legal Director Joe Guth was an appointed member of the Cumulative Impacts and Precautionary Approaches Workgroup, which helped OEHHA develop the report. Joe says the disclaimer does ensure that no action on the report will be taken immediately and therefore could be interpreted as a delaying tactic, perhaps in response to industry pressure.

"Or it could very well be that OEHHA just wants to get a detailed methodology established before the various divisions within CalEPA take their own individual, disparate approaches." There is apparently, he said, considerable resistance to these far-reaching changes from some of the divisions within CalEPA.

A February 11, 2011 industry letter to the new administration of Governor Jerry Brown complained about "a series of recent and significant actions" by OEHHA occurring "during the transition from the outgoing Schwarzenegger administration to your administration." Among other things it cited the cumulative impacts report and emphasized that it had been issued on December 31, 2010.

High time. As required by law. After 11 years.



  II. A screening method to compare cumulative impact among communities   TOP
 California Environmental Protection Agency

Excerpted from Cumulative Impacts: Building a Scientific Foundation, California Environmental Protection Agency, Office of Environmental Health Hazard Assessment, December 2010

(complete and fully referenced version can be accessed here)

Many Californians live in close proximity to multiple sources of pollution. Past industrial activities in many areas have left a toxic legacy of Brownfields and Superfund sites where chemicals seeped into underlying soil and groundwater.

Despite regulation of major industrial facilities, these facilities still emit air pollutants and discharge water pollutants. Rail yards, freeways, ports, and other facilities bring together vehicles and equipment that produce emissions from diesel fuel and gasoline.

Today, communities by these locations are predominantly low-income, often with a large percentage of ethnic minorities and non-English speakers. Like other low-income communities, they face additional challenges that can affect the health of their residents, including limited access to health care; poor nutrition stemming in part from a shortage of grocery stores; and a lack of parks and open space.

Living next to industrial facilities, congested freeways, or fields where agricultural chemicals are applied, many residents worry about possible links between environmental quality in their communities and their health. They ask difficult questions to civic leaders, policymakers and regulators, including:

  • Do these decision makers understand the cumulative impacts on our community of numerous sources of pollution that affect our air, water, and soil?
  • Does anyone share our concern that our community's demographics and public health challenges are making us more vulnerable to the effects of environmental pollution?
  • Are the cumulative impacts of pollution in my community greater than in other communities?

This report presents a screening methodology that, when fully developed, can be used by Cal/EPA programs and others as a first step to answer the above questions.

The need to address cumulative impacts

Environmental programs are intended to protect public health and the environment from the adverse effects of toxic and hazardous contaminants and other harmful agents. Current environmental regulations generally set limits for individual pollutants in air, water, soil, food or other sources of exposure at levels that pose the lowest possible risk to human or ecological health.

While this approach has been effective in controlling media-specific exposures in the past, it does not account for exposure to multiple pollutants from multiple sources. Age, genetic characteristics, and pre-existing health conditions also may increase the risk for some populations of adverse health effects from exposure to pollutants.

Scientists have also begun to look at other human factors when assessing health risks. Income, access to health care, and other socioeconomic factors may influence the effect of environmental pollutants. These factors influence the likelihood of exposure to pollutants or proximity to sources of pollution. For example, higher pollutant levels tend to occur in low-income neighborhoods and among communities of color. Also, health disparities have been documented between groups of people of different income levels and among different racial or ethnic groups. (See "Health Disparities.")

Cumulative impact analysis provides a fuller picture by examining multiple chemicals, multiple sources, public health and environmental effects, and characteristics of the population that influence health outcomes. Approaches to assess and mitigate cumulative impacts are a logical next step in applying the best available science to environ-mental protection programs. As Cal/EPA further develops, adopts, and implements cumulative impact analyses, it will move closer to achieving its environmental justice and public health goals while better protecting the environment and the people of California.

The report's foundation is the working definition for "cumulative impacts" adopted by the Cal/EPA Interagency Working Group:

Cumulative impacts means exposures, public health or environmental effects from the combined emissions and discharges, in a geographic area, including environmental pollution from all sources, whether single or multimedia, routinely, accidentally, or otherwise re-leased. Impacts will take into account sensitive populations and socioeconomic factors, where applicable and to the extent data are available.

A scientific screening method for analyzing cumulative impacts in communities

This method uses a simple formula to screen for relative levels of cumulative impacts among communities based on the five components from Cal/EPA's working definition that describe the geographic area: exposures, public health and environmental effects, sensitive subpopulations and socioeconomic information. The components are divided into two groupings: pollution burden and population characteristics.

As indicated in the working definition, cumulative impacts include the sum total of pollution in a geographic area. This total is the "pollution burden." At the same time, the working definition states that cumulative impacts need to take into account factors that relate to the people living in the geographic area. These factors are the "population characteristics." The separation of these components into two groups becomes important when we calculate cumulative impacts.

The pollution burden components are exposures, environmental effects and public health effects. Measures of exposure can best be indicated by environmental monitoring data. While emissions by themselves do not necessarily indicate exposure, they can be used as a surrogate suggesting the potential (though not certain) contact with pollutants. Environmental effects reflect the physical conditions of the community, such as contamination by hazardous materials, and facilities where hazardous chemicals are stored, treated or disposed. Public health effects include health outcomes that may be linked to chemical exposures, such as asthma, low birth weight and some cancers.

The population characteristics are sensitive populations and socioeconomic factors.

Sensitive populations include the percentages of the population in the community that are children or elderly. Where appropriate, sensitive populations may also consist of individuals with certain diseases or physical conditions that render them more vulnerable to the effects of pollution, such as pregnant women. Socioeconomic factors reflect characteristics of the population that have the potential to make them more vulnerable to pollutants, such as poverty level, minority proportion, or educational attainment

For the screening analysis of cumulative impacts in a community, each of the five components is assigned a score based on the relative magnitude of impact (Table). As illustrated in the Figure, the five scores are added and then multiplied as indicated in the formula to yield a final score representing the cumulative impacts of multiple pollution sources in that community.

Table: Range of scores for each component
ComponentRange of Possible Scores
Exposures1-10
Environmental effects1-5
Public health effects1-5
Sensitive populations1-3
Socioeconomic factors1-3
Cumulative impact6-120

Figure: Formula for estimating relative cumulative impact among communities

What can this methodology be used for?

A screening method would:

  • Distinguish higher-impacted from lower-impacted communities. Cal/EPA programs could target those communities with the highest impact scores for enforcement and incentive programs.
  • Identify which of the components (exposures, public health effects, socioeconomic factors, etc.) are likely to contribute the most to the community's cumulative impact and which of those components Cal/EPA programs can address.
  • Identify a highly impacted area. This could be included as additional information in a risk assessment.
  • Support intra-agency efforts to address multimedia impacts.

What can't the methodology be used for?

  • A comprehensive assessment of the cumulative impacts of all pollutants within a community.
  • Detecting the impact of small incremental changes within a community.
  • Determining the cause of health outcomes in a community (for example, attributing impacts to a specific source or facility) or predicting human health risks.
  • As a human health risk assessment.
  • Supplanting existing regulatory requirements.

(complete and fully referenced version can be accessed here)



  III. Health disparities, socioeconomic factors, and their relation to pollution-related diseases   TOP
 California Environmental Protection Agency

Excerpted from Cumulative Impacts: Building a Scientific Foundation, California Environmental Protection Agency, Office of Environmental Health Hazard Assessment, December 2010

(complete, fully referenced version can be accessed here)

Differences in specific health outcomes have been well documented among various segments of the population in California, the United States, and worldwide. More specifically, health disparities or health inequalities have been defined as “potentially avoidable differences in health (or in health risks that policy can influence) between groups of people who are more or less socially advantaged. These differences systematically place socially disadvantaged groups at further disadvantage on health.” Social advantage is “position in the social hierarchy determined by wealth, power, and/or prestige,” which can include factors such as poverty, race, ethnicity, or discrimination. As environmental justice in California concerns the fair treatment of people of all races, cultures, and incomes with respect to the development, adoption, implementation, and enforcement of environmental laws and policies (Government Code Section 65040.12), the degree to which activities at Cal/EPA may influence and reduce such health disparities is relevant.

A large body of literature documents health disparities with respect to various socio-economic factors, including race/ethnicity. Disparities in health vary by cause of death, geographic area, and over time, though the underlying causes and their contribution have not been firmly established. In this section, we emphasize the disparities that have been observed in the literature for diseases or health outcomes that have also been associated with exposures to environmental pollutants.

Mortality Disparities

Consistent relationships have been observed between higher mortality from all causes and lower socioeconomic position. A life-expectancy gap between the most- and least-deprived groups was observed when applying a broad measure of socioeconomic deprivation for U.S. populations that included indicators of poverty, income distribution, wealth, education, employment, occupation, and housing quality. While the trend over time is increased life expectancy among all groups, the gap between the most- and least-deprived socioeconomic groups has increased. Similarly, in the U.S., a gap in age-standardized death before age 65 or premature mortality between the highest and lowest socio-economic group, based on median family income, increased in the 1980s and 1990s. Age-adjusted death rates also declined significantly in the U.S. with increasing educational attainment.

With respect to race, significantly higher death rates for African Americans than whites in California have been documented regardless of socioeconomic position, as measured by educational attainment. On the other hand, this study also found mortality among Hispanic and Asian populations in California to be slightly lower than among white populations. Greater premature mortality from heart disease contributes to the higher death rates among African Americans. Higher death rates among African Americans have also been observed in U.S. populations as a whole. When broken down by specific causes of death, this gap in death rates is most influenced by homicide, hypertension, heart disease, diabetes, respiratory disease and some cancers.

Infant Mortality Disparities

Infant mortality rates in the U.S. declined dramatically through the 20th century. Increases in educational attainment correlate with reductions in infant mortality across races. However, gaps in relative rates of infant mortality between groups of mothers based on educational attainment widened between 1986 and 2001. When examining infant mortality by race, the mortality rate for black infants is more than twice the rate for white and Hispanic infants, and cannot be explained even after adjusting for numerous factors. Infant mortality from circulatory and respiratory disease and sudden infant death is greater among black mothers than among white and Latina mothers.

Perinatal Outcome Disparities

Differences in adverse perinatal outcomes, such as low birth weight and preterm delivery, have been observed across various socioeconomic and racial groups. The rate of pre-term births is more than 50 percent higher among black women compared to Hispanic and non-Hispanic white women. Similarly, rates for infants with low and very low birth weight are two to three times higher among black women than among Hispanic or non-Hispanic white women. Although income, education, prenatal care, marital status, and substance use have been identified as contributors to different birth outcomes, these factors alone do not appear to explain the disparities.

Asthma Disparities

Data from health interview surveys have shown that low-income people have higher rates of asthma symptoms and hospitalizations. This has been shown for both California populations and the U.S. as a whole. Furthermore, in California there is a clear relationship between lower income levels and increasing asthma hospitalizations, although differences among income levels for lifetime prevalence (the actual number of people with asthma) do not exhibit the same relationship. Conflicting evidence was demonstrated in another study that identified an inverse relationship between some measures of asthma prevalence in Southern California and different measures of socioeconomic position.

With respect to race/ethnicity, asthma is much more prevalent in California among African Americans and American Indians/Alaska Natives compared to other races. This difference is even greater for asthma among African Americans when measured by such yardsticks as health care utilization and mortality (emergency department visits and hospitalizations). Among children of different races/ethnicities in the U.S., rates of asthma are highest in Puerto Rican children, followed by African-American, white, and Mexican-American children. African-American children are almost three times more likely to be hospitalized for asthma than children of all other races in California.

Cancer Disparities

Differences in various measures of cancer status, including incidence, survival, screening prevalence, stage at diagnosis, and mortality among different socioeconomic and racial/ethnic groups have been well documented for different types of cancer. Distinct cancers have different risk factors associated with them. There are many possible factors that are potentially responsible for these differences across specific groups, including tobacco smoking, alcoholic beverage consumption, diet, reproductive factors, infectious diseases (particularly sexually transmitted disease), chronic infections, occupational factors, unemployment, and environmental factors.

Among major racial groups in the U.S., cancer incidence is highest among African Americans for lung and bronchial, colon and rectal, prostate and all cancer sites combined. Differences by race persist even after controlling for poverty.

Later-stage diagnosis appears to be the primary impact on mortality disparities. White women of higher socioeconomic status have higher breast cancer incidence, though the incidence of more advanced breast cancers is higher in African-American women. Additionally, breast cancer survival among African-American women is lower than that of white women and has grown since the mid-1980s. With respect to the higher prostate cancer mortality in African-American men, the stage at diagnosis appears to be the primary driver of the disparity.

Cardiovascular Disease Disparities

Disparities in cardiovascular disease (CVD) and risk factors such as high blood pressure, obesity, smoking and diabetes have been observed across different socioeconomic and racial groups in the U.S. Mortality from heart diseases and stroke is higher for blacks compared to whites. Populations of Hispanics, Asian/Pacific Islanders, and American Indian/Alaska Natives show comparable and sometimes lower death rates than white populations for CVD. Latinos born in the U.S. are more likely to be diagnosed with high blood pressure than foreign-born Latinos.

Evidence negating genetic differences with respect to CVD disparities comes from studies of the disease prevalence in black populations of West African origin, which suggests that the physical and social environments are important determinants in the development of disease.

Higher socioeconomic status, as measured by educational attainment, income, and poverty status, was found to be associated with lower prevalence of CVD and its risk factors. Additionally, the gap between socioeconomic groups appears to be widening for some cardiovascular disease risk factors such as smoking and diabetes.

(complete, fully referenced version can be accessed here)



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