Biology 202, Spring 2005
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Lead Poisoning, Delinquency, and Mitigation of Criminal Culpability

For decades, lead, chemically referred to as pb24, has been known to be a hazardous toxicant particularly detrimental for children (1). It is estimated that 2.2 percent of all preschoolers in the US, totaling approximately 434,000 children, have elevated lead levels sufficient to interfere with their neurological development (2). The children who are usually exposed to lead tend to live in older homes and come from poorer families who cannot afford to replace the two most common sources of lead to children in their homes, lead paint and lead plumbing (3). Although lead can affect several areas of the body, the neurological damage is often quite severe for individuals exposed to even slight amounts of lead during brain development. This damage often results in behavioral problems, reasoning and attention deficits, and low IQ and mental retardation; conditions that occasionally lead to deviant behavior. In neighborhoods where lead exposure is so common and unavoidable due to the impoverished state of the inhabitants, the lead exposure of the children that develop neurological deficits and subsequently exhibit deviant behavior must be considered when determining their degree of culpability for a crime. If the physical state and composition of the brain determine the behavior of an individual, a brain damaged by lead poisoning can be the source of socially abnormal behavior.

The most common sources of exposure to lead in the household are chips or dust from lead paint, commonly used between the years1900 and 1977 until the federal government banned lead as an additive to paint used for housing in 1978 (3). It has been estimated that 38 million homes in which children are raised have deteriorating lead surfaces, and in about 24 million homes, or 25% of the nation's housing, the lead paint is extremely hazardous (4). This state of the nation's housing stock underscores that although lead paint has been banned from use since 1978, the problem still exists for occupants of homes built before then, particularly urban, low-income occupants.

Lead is referred to as xenobiotic, meaning it is a foreign substance with no useful role in human physiology, toxic even in minute quantities. Rather than breaking down to be eliminated as a waste product, lead accumulates in the body's bones and tissues because the body recognizes it as if it were calcium. It may be absorbed from the gastrointestinal tract or through the respiratory system. Lead exposure can result in low sperm counts in men and can increase the risk of miscarriage or stillbirth among women. It damages the kidneys and gastrointestinal tract, and can lead to a host of neurological problems including decreased cognitive abilities (5). and increased behavior problems in children (6). The current trigger level for lead, decreased over the years as scientific understanding about lead's effects increased, is 10µg/dL (7).

Although lead can cause harm to children and adults alike, children still developing mentally and physically experience the most seriously deleterious effects of lead poisoning. Children are more likely to be exposed to lead because their exposure to certain toxins increases as they play outdoors. They are shorter than adults, which means they can breathe dust, soil, and vapors close to the ground. Children are smaller than adults, therefore childhood exposure results in higher doses of chemicals per body weight (8). They are more likely to be irrevocably damaged by lead poisoning because lead causes damage to the nerve cells of the brain while the brain is still developing. Once ingested, lead inhibits a child's ability to absorb iron, necessary for brain, nerve and bone development (3). The dendrites of nerve cells in developing brains are cut short by lead, thereby reducing the connections between axons among adjacent neurons. Dendrites are most plentiful during the early years of childhood, especially between the ages of 1 and 5, and thin naturally with age. Thus it is crucial for healthy development to establish as many connections between neurons in the brain as possible through education and stimulation between the ages of 1 and 5. When children are exposed to lead which limits the connections being made during this important developmental period, the brain is irrevocably disadvantaged, resulting in decreased amounts of gray matter (9).(10). Chelation therapy, which involves reducing the lead concentrations in the bloodstream by orally administering succimer, or injecting ethylenediaminetetraacetic acid (EDTA), a ligand that binds metals, has been shown to be ineffective at increasing already damaged neurons and increasing diminished IQ (11). Therefore, even when individuals undergo treatment during childhood, the damaged areas cannot be recovered.

The neurological damage resulting from exposure to lead can result in abnormal behavior, exhibited through increased irritability and violence, learning disabilities, mental retardation, and other functional difficulties. The social effects of these abnormal behaviors through disciplinary actions, peer isolation, falling behind in school, drug abuse, domestic abuse, and a lack of understanding about the basis of an individual's impairments may also compound the neurological damage, resulting in psychological trauma, which studies show can cause other types of brain damage (12). Additionally, lead exposure is known to cause attention problems for children (13). making academic success and effectively adapting to society difficult. All these conditions have been known to result in an individual's inability to function in society or possess adaptive skills. Inability to function in society often results in deviancy of various kinds, and at times the deviancy that is a symptom of an individual's neurological damage is so seriously a breach of the mores of social structure that it is viewed by our legal system as criminal.

Dr. Herbert Needleman of the Psychiatry Department at University of Pittsburgh has conducted several studies in the past decades dealing with children's exposure to lead, sources of lead exposure, and social, behavioral, and neurological consequences of lead exposure. In 2002 he examined 194 youths convicted in the Juvenile Court of Allegheny County, PA, and 146 non-delinquent controls from high schools in Pittsburgh, PA. Lead levels measured from the tibias of the subjects using K X-ray fluorescence spectroscopy revealed substantially higher lead levels in the bones of the delinquent youths at an average of 11 parts per million (ppm) compared to 1.5 ppm in the non-delinquent group (14). Dr. Needleman described this study, which was the first to show lead exposure is higher in convicted delinquents than in non-delinquents, as a positive step towards connecting lead poisoning with delinquency. (15).

Dr. Needleman's groundbreaking work in the area of lead exposure and behavior warrants further investigation into the area of responsibility for behavior when an affected individual commits crime. According to all the studies, lead poisoning is a disease of poverty and is in no way the fault of the person afflicted. Therefore, the effects of lead poisoning, increased aggressive behavior, low intelligence, learning disabilities, and anti-social behavior, all of which are known predictors of crime, should be mitigation of the culpability of offenders afflicted with lead poisoning.

Lead poisoning has been epidemic in the city of Philadelphia for decades. Although it would seem the problem of lead in the US as well as in Philadelphia is being ameliorated and that the numbers of children being exposed is decreasing, the children who were affected by the high doses of lead far more common and rampant in the last century are now adults, trying to function in society with the effects of their exposure. In addition, those children who are currently being exposed to lead need a society that will be able to better understand the implications of this environmental toxin for delinquency and execute justice more effectively when they become adults. Human exposure to lead continues to be a crisis of public health, criminal justice, and environmental racism, and what is necessary for its complete elimination in schools and housing is a change in people's attitudes about the extent of lead poisoning in order to gain more public and federal support and make this problem of poor minorities in the inner-city everyone's problem.

References

1) US Department of Health and Human Services, The Nature and Extent of Lead Poisoning in Children in the United States: A Report to Congress 1 (July 1988). 2) Centers for Disease Control and Prevention. 2003. Second National Report on Human Exposure to Environmental Chemicals. NCEH Pub. No. 02-0716.
3) Center for Disease Control and Prevention. 1991. Preventing Lead Poisoning in Young Children: A Statement by the Centers for Disease Control. Atlanta, GA.
4)US Department of Housing and Urban Development (HUD), accessed: 4/4/05
5) Thacker, S.B. et al.. 1992. Effects of Low-Level Body Burdens of Lead on the Mental Development of Children. Archives of Environmental Health, Vol. 47.
6) Konopka, Allan. 2003. The Secret Life of Lead, Living on Earth and World Media Foundation.
7) Needleman, Herbert L.. The Poisoning of America's Children: Lead Exposure, Children's Brains, and the Ability to Learn. National Health/ Educational Consortium, Occasional Paper #6. November 1992
8) Rodier, Patricia M.. 1994. Developing Brain as a Target of Toxicity, in symposium: "Preventing Child Exposures to Environmental Hazards: Research and Policy Issues." University of Rochester, New York.
9) Hrdina, P.D., et al..1980. Neurochemical Correlates of Lead Toxicity. In eds. Singhal, R.L.; Thomas, J.A.; Lead Toxicity. Baltimore, MD, Urban and Schwarzenberg.
10) Nathanson, J.A. 1977. Lead-inhibited Adenylate Eyclase, a Model for the Evaluation of Chelating Agents in the Treatment of Lead Toxicity. Journal of Pharmacy and Pharmacology, Vol. 29.
11) Rogan W. J., Dietrich K. N., et al.. 2001. The Effect of Chelation Therapy with Succimer on Neuropsychological Development in Children Exposed to Lead, New England Journal of Medicine, 344.
12) Rosen J. F., Mushak P.. 2001. Primary Prevention of Childhood Lead Poisoning — The Only Solution, New England Journal of Medicine, 344.
13) Minder, Barbara, et al.. 1994. Exposure to Lead and Specific Attentional Problems in Schoolchildren. Journal of Learning Disabilities, Vol. 27.
14) Needleman, Herbert L., et al.. 2002. Bone Lead Levels in Adjudicated Delinquents: A Case Control Study. Neurotoxicology and Teratology, Vol. 24.
15)Lead link to youth crime," BBC News Online, 7 January, 2003


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