Harvard University researchers found that children with higher cadmium levels are three times as likely to have learning disabilities than those with lower levels.
Background:
While elements such as arsenic, lead, and mercury are often the first to pop up when discussing or thinking about toxic elemental species and human health, cadmium remains the lesser mentioned metal compromising the health of many — especially children. Although cadmium is naturally found in the environment, the heavy metal is also released by battery manufacturers, smelters, electroplating plants, and many other industries. Cadmium is also present in inexpensive jewelry for kids imported from China especially since lead has been regulated more strictly.
The new study:The researchers evaluated associations between urine cadmium concentration and reported learning disabilities (LD), special education utilization, and attention deficit hyperactivity disorder (ADHD) in US children using National Health and Nutrition Examination Survey (NHANES) data. They analyzed data from a subset of participants in NHANES (1999-2004) who were 6-15 years old and had spot urine samples analyzed for cadmium. A total of 2,199 children were included in the study, with 12.6 percent of them having a learning disability and 10.5 percent being enrolled in special education classes. Those with the highest cadmium levels were 3.21 times more likely to have a learning disability than children less exposed. The researchers also stress the point, that they observed these associations at exposure levels that were previously considered to be without adverse effects and these levels are common among U.S. children.
While current and future research will likely continue to make the dangers of cadmium more well known, past studies are collectively very consistent in showing that cadmium is a dangerous neurotoxin. High levels of exposure can lead to neurological problems as well as mental retardation and decreased IQ in children. The scientists highly recommend that the government re-evaluate cadmium’s place in society by instituting stricter rules for cadmium in food, soil, workplaces, and consumer products.
In Europe, cadmium compounds have been included in the list of chemicals of very high concern (SIN List) in order to speed up the implementation of REACH (see the news below) and the European Commision banned cadmium in plastics in December 2011.
The new study
T. Ciesielski, J. Weuve, D.C. Bellinger, J. Schwartz, N. Lanphear, R.O. Wright,
Cadmium Exposure and Neurodevelopmental Outcomes in U.S. Children, Environ. Health Perspect. (2012).
doi: 10.1289/ehp.1104152
Analytical techniques applied for this study Inductively coupled plasma mass spectrometry (for cadmium in spot urine of children)
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Related EVISA Resources Brief summary: ICP-MS: A versatile detection system Link Database: Industrial use of cadmium Link Database: Toxicity of cadmium Link Database: Environmental cadmium pollution
Related EVISA News February 12, 2012: Study links high levels of cadmium and lead in blood to pregnancy delay June 7, 2011: European Commission announces ban on cadmium in plastics September 18, 2008: REACH Update: List of 300 chemicals of very high concernlast time modified: February 15, 2012
