In April 2014, Michigan state officials made a decision to change the water source for the City of Flint from Detroit’s municipal system to the Flint River. This was intended to be a temporary measure until lines could be placed to Lake Huron. Local officials did not to use the additive orthophosphate, an anti-corrosive measure required by the Clean Water Act. Without orthophosphate, lead began to leach from the aging Flint water lines. At the same time, coliforms were found in the water and, therefore, high levels of chlorines were used and a boil alert was established. In addition, infectious disease surveillance revealed a rise in Legionella cases in Genesee County, later determined to be related to the condition of the water lines during this time.
In September, 2015, pediatrician Mona Hanna-Attisha, MD, MPH, FAAP, presented results of a data analysis of blood lead results from children evaluated at the Hurley Medical Center in Flint. The mean value for the lead levels had increased from around 2.5 μg/dL when on the Detroit water source to over 4.0 μg/dL after the to the Flint River source without the anti-corrosive. The percentage of levels ≥5 μg/dl increased from around 2.4% to around 4.9%.
In October, 2015, the water source was switched back to Detroit’s municipal system. Although orthophosphates were already present in this source water, there was insufficient “coating” on the lines to eliminate the risk of lead leaching; the time required for sufficient accumulation is unknown. It is also unknown whether the levels will ever decrease below regulatory limits (Hanna-Attisha et al, 2016).
Health Effects of Lead:
During pregnancy, lead may be mobilized along with calcium from maternal stores in bone. Lead freely crosses the placenta, but excretion into breast milk is negligible unless maternal blood lead level is greater than 40 to 50 mcg/dL.
Children, particularly toddlers, are at greatest risk for exposure to lead. Exploratory and hand-to-mouth activities increase exposure during a period of vulnerability in terms of nutrition, growth, and development. The most concerning health effects are seen in the central nervous and hematologic systems. There is evidence that lead interferes with a variety of enzymes that modulate synapse formation, normally at peak levels in the first three years of life, as well as the heme-synthetic pathway.
Since the 1970s, mounting evidence of lead’s toxicity has led to progressive reductions in the blood lead “level of concern,” from 60 mcg/dL to 10 mcg/dL. This approach gave way in 2012 to the “reference level,” currently 5 mcg/dL; children at or above this reference level are among the top 2.5% of levels in the 1- to 5-year-old group. The reference level reflects the concept that there is no known “safe” level of lead. Although it can be difficult to predict clinical effects in the individual child, elevated lead levels have been associated with hyperactivity and aggression as well as deficits in IQ and attention.
Although progress has been made in reducing lead poisoning in the US, recent events in Flint demonstrate that lead still presents a risk to children. And although unacceptable lead in water has been in the media spotlight, lead in deteriorating residential paint remains a threat to children living in older homes.
The Region 5 Pediatric Environmental Health Specialty Unit (PEHSU) has regularly been in contact with health and public officials close to the situation in Flint, and has been actively involved in providing consultation services to families who are concerned about lead in the water. PEHSUs will continue to provide outreach at every opportunity, in Flint, and across the country. If you, or someone you know, has questions or concerns about lead in water near you, please reach out to your PEHSU: http://www.pehsu.net/findhelp.html
PEHSU Lead Resources:
- PEHSU Fact Sheet: Medical Management of Childhood Lead Exposure and Poisoning Recommendations for Health Professionals
- PEHSU Fact Sheet: Chelation Therapy
- Environmental Protection Agency: http://www.epa.gov/flint
- Agency for Toxic Substances and Disease Registry: http://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=22
- Centers for Disease Control and Prevention: http://www.cdc.gov/nceh/lead/
- American Academy of Pediatrics: https://www.aap.org/en-us/advocacy-and-policy/aap-health-initiatives/lead-exposure/Pages/default.aspx
- American Journal of Public Health: http://ajph.aphapublications.org/doi/full/10.2105/AJPH.2015.303003
- FiveThirtyEight article: http://fivethirtyeight.com/features/what-went-wrong-in-flint-water-crisis-michigan/