Background Influence

Toxic influences in neighborhoods

Parent construct: Physical environment

Biological toxicants often abound in poor neighborhoods. They are detrimental to general health, behavior, cognitive capacity, and social capital.

Lead (Pb) toxicity is well documented. Many assume this is effect is only due to lead paint. However, lead in dust and water is also a problem. For instance, a recent study of 3,111 American counties shows that the murder rate is 4.12 times higher in the counties with the highest levels of lead than it is in the ones with the lowest levels.1 The effect is greatest in the poorest counties.2

Even low levels of lead exposure lowers IQ of children,3 increases ADHD,4,5 and increases conduct disorders.6 The effects are greater when people have other stressors in their lives.7

Another airborne toxicant is black carbon, a marker for traffic particles. It is associated with decreased verbal and nonverbal intelligence and impaired memory.8

Other toxic influences are less well known, but well proven scientifically. For example, omega-3 fatty acid deficiency and cytotoxic levels of omega-6 resulting from the consumption of fast foods, processed foods, and free-lunch programs, harms infant and child cognition and development into the 8th year of life.9,10,11 It increases inflammatory diseases of childhood and increases impulsivity,12 aggression/homicide and mental illnesses.13,14 These adverse fatty acid ratios also cause obesity.15 And, they worsen the negative impact of lead exposure.13

Some toxins involve physical but not chemical mechanisms. For example, the chronic noise of many urban poor neighborhoods is associated with reductions in reading and math scores, even when studies control for poverty levels.16 Even the noise generated by the classroom itself affects literacy.17

Some toxins involve only social mechanisms. Witnessing violence directly at home, in the neighborhood or in school 18 or indirectly via media19,20 contributes to children’s stress and their aggressive behavior. Even exposure to verbal coercion can have this effect. 21,22 Chronic exposure to these experiences appears to reset young people’s biology so that they are prone to impulsivity, poor self-regualation, early sexual maturity, addictions, psychiatric disorders and “gang-like behavior.” 23,24,25


  1. Stretesky, P. B., & Lynch, M. J. (2001). The relationship between lead exposure and homicide. Archives of Pediatrics & Adolescent Medicine, 155(5), 579-582.  

  2. Stretesky, P. B., & Lynch, M. J. (2004). The relationship between lead and crime. Journal of Health & Social Behavior, 45(2), 214-229.  

  3. Jusko, T. A., Henderson, C. R., Lanphear, B. P., Cory-Slechta, D. A., Parsons, P. J., & Canfield, R. L. (2008). Blood lead concentrations < 10 microg/dL and child intelligence at 6 years of age. Environ Health Perspect, 116(2), 243-248. doi: 10.1289/ehp.10424  

  4. Braun, J. M., Kahn, R. S., Froehlich, T., Auinger, P., & Lanphear, B. P. (2006). Exposures to environmental toxicants and attention deficit hyperactivity disorder in U.S. children. Environ Health Perspect, 114(12), 1904-1909.  

  5. Nigg, J. T., Knottnerus, G. M., Martel, M. M., Nikolas, M., Cavanagh, K., Karmaus, W., et al. (2008). Low blood lead levels associated with clinically diagnosed attention-deficit/hyperactivity disorder and mediated by weak cognitive control. Biological Psychiatry, 63(3), 325-331.  

  6. Braun, J. M., Froehlich, T. E., Daniels, J. L., Dietrich, K. N., Hornung, R., Auinger, P., et al. (2008). Association of environmental toxicants and conduct disorder in U.S. children: NHANES 2001-2004. Environ Health Perspect, 116(7), 956-962. doi: 10.1289/ehp.11177 [doi]  

  7. Fergusson, D., Swain-Campbell, N., & Horwood, J. (2004). How does childhood economic disadvantage lead to crime? Journal of Child Psychology & Psychiatry & Allied Disciplines, 45(5), 956-966.  

  8. Suglia, S. F., Gryparis, A., Wright, R. O., Schwartz, J., & Wright, R. J. (2008). Association of black carbon with cognition among children in a prospective birth cohort study. American Journal of Epidemiology, 167(3), 280-286.  

  9. Helland, I. B., Smith, L., Saarem, K., Saugstad, O. D., & Drevon, C. A. (2003). Maternal supplementation with very-long-chain n-3 fatty acids during pregnancy and lactation augments children's IQ at 4 years of age. Pediatrics, 111(1), e39-44.  

  10. Hibbeln, J., Davis, J. M., Steer, C., Emmett, P., Rogers, I., Williams, C., et al. (2007). Maternal seafood consumption in pregnancy and neurodevelopmental outcomes in childhood (ALSPAC study): an observational cohort study. The Lancet, 369(9561), 578-585. doi: DOI:10.1016/S0140-6736(07)60277-3  

  11. Tofail, F., Kabir, I., Hamadani, J. D., Chowdhury, F., Yesmin, S., Mehreen, F., et al. (2006). Supplementation of fish-oil and soy-oil during pregnancy and psychomotor development of infants. Journal of Health, Population & Nutrition, 24(1), 48-56.  

  12. Gale, C. R., Robinson, S. M., Godfrey, K. M., Law, C. M., Schlotz, W., & O'Callaghan, F. J. (2008). Oily fish intake during pregnancy--association with lower hyperactivity but not with higher full-scale IQ in offspring. Journal of Child Psychology and Psychiatry, 49(10), 1061-1068. doi: 10.1111/j.1469-7610.2008.01908.x  

  13. Arora, M., Ettinger, A. S., Peterson, K. E., Schwartz, J., Hu, H., Hernandez-Avila, M., et al. (2008). Maternal dietary intake of polyunsaturated fatty acids modifies the relationship between lead levels in bone and breast milk. Journal of Nutrition, 138(1), 73-79.  

  14. Hibbeln, J. R., Nieminen, L. R., Blasbalg, T. L., Riggs, J. A., & Lands, W. E. (2006). Healthy intakes of n-3 and n-6 fatty acids: estimations considering worldwide diversity. American Journal of Clinical Nutrition, 83(6 Suppl), 1483S-1493S.  

  15. Dziedzic, B., Szemraj, J., Bartkowiak, J., & Walczewska, A. (2007). Various dietary fats differentially change the gene expression of neuropeptides involved in body weight regulation in rats. Journal of Neuroendocrinology, 19(5), 364-373.  

  16. Haines, M. M., Stansfeld, S. A., Head, J., & Job, R. F. (2002). Multilevel modelling of aircraft noise on performance tests in schools around Heathrow Airport London. J Epidemiol Community Health, 56(2), 139-144.  

  17. Shield, B. M., & Dockrell, J. E. (2008). The effects of environmental and classroom noise on the academic attainments of primary school children. J Acoust Soc Am, 123(1), 133-144. doi: 10.1121/1.2812596  

  18. Embry, D. D., Flannery, D. J., Vazsonyi, A. T., Powell, K. E., & Atha, H. (1996). PeaceBuilders: A theoretically driven, school-based model for early violence prevention. American Journal of Preventive Medicine, 12(5, Suppl), 91.  

  19. Huesmann, L. R., Eron, L. D., Lefkowitz, M. M., & Walder, L. O. (1973). Television violence and aggression: The causal effect remains. American Psychologist, 28(7), 617-620.  

  20. Huesmann, L. R., Lagerspetz, K., & Eron, L. D. (1984). Intervening variables in the TV violence-aggression relation: Evidence from two countries. Developmental Psychology, 20(5), 746-775.  

  21. Patterson, G. R., Dishion, T. J., & Bank, L. (1984). Family interaction: A process model of deviancy training. [doi:10.1002/1098-2337(1984)10:3<253::AID-AB2480100309>3.0.CO;2-2]. Aggressive Behavior, 10(3), 253-267. doi: 10.1002/1098-2337(1984)10:3<253::aid-ab2480100309>;2-2  

  22. Patterson, G. R., & Stouthamer-Loeber, M. (1984). The correlation of family management practices and delinquency. [doi:10.2307/1129999]. Child Development, 55(4), 1299-1307. doi: 10.2307/1129999  

  23. Embry, D. D. (2002). Nurturing the genius of genes: The new frontier of education, therapy, and understanding of the brain. Brain & Mind, 3(1), 101-132.  

  24. Embry, D. D. (2005). Reconciling Behavioral and Brain Science in Violence Prevention: Theory and Practice. In D. J. Flannery (Ed.), Current Perspectives on Violence Prevention (Vol. 1, pp. 142-167). Kent, OH: Kent State University; Institute for the Study and Prevention of Violence.  

  25. Tsankova, N., Renthal, W., Kumar, A., & Nestler, E. J. (2007). Epigenetic regulation in psychiatric disorders. Nat Rev Neurosci, 8(5), 355-367.