Archives for November 2014

Medical Geology: An Emerging Discipline in Environmental and Human Health

Olle Selinus, PhD
Former geologist at the Geological Survey of Sweden (SGU), and now Associated Professor at Linneaus University in Kalmar, Sweden. Board member of CONEM.

Medical geology is the science dealing with the influence of geology on the distribution of health in humans and animals. Medical geology is a rapidly growing discipline that has the potential of helping medical and public health communities all over the world pursue a wide range of environmental and naturally induced health issues. Medical geology brings together geoscientists and medical/public health researchers to address health problems caused, or exacerbated by geological materials (rocks, minerals, atmospheric dust, and water) and processes.  Among the environmental health problems that geoscientists are working on in collaboration with the medical and public health community are: exposure to toxic levels of trace essential and non-essential elements such as arsenic and mercury; trace element deficiencies; exposure to natural dusts and to radioactivity; naturally occurring organic compounds in drinking water; volcanic emissions, etc.

Among the medical geology described are examples of both deficiency and toxicity of trace element exposure. Goiter is a widespread and serious health problem in many developing countries caused by deficiency of iodine. Deficiency of selenium in soil is the principal cause of juvenile cardiomyopathy and muscular abnormalities. Overexposure to arsenic is one of the most widespread medical geology problems affecting more than one hundred million people in Bangladesh, India, China, Europe, Africa and North and South America. The arsenic exposure is primarily due to naturally high levels in groundwater, but combustion of mineralized coal has also caused arsenic poisoning in several developing countries. Dental and skeletal fluorosis also impacts the health of millions of people around the world and is due to naturally high concentrations in drinking water and, to a lesser extent, coal combustion. Other medical geology issues described include geophagia in developing countries, exposure to radon, natural global dusts and ingestion of high concentrations of organic compounds in drinking water.

Promotion of medical geology under ICSU, UNESCO etc, under leadership from Sweden, has been carried out at meetings in many countries, organization and sponsoring of symposia on medical geology and also providing financial support for students and professionals to participate. Short courses have been presented in almost 45 countries since 2001, attended by thousands of students and professionals with backgrounds in geoscience, biomedical/public health science, enviromental science, chemistry, etc.

The International Medical Geology Association (IMGA) was established in January 2006. This was done from Sweden. Every second year IMGA has an international conference. The next will be in Portugal July 2015. Information can be found on the website



Selinus O, ed. Medicinsk geologi. Lund: Studentlitteratur, 2010.

Selinus O, Finkelman B, Centeno J, eds. Medical Geology: A Regional Synthesis. Dordrecht: Springer, 2010.

Selinus O, Alloway B, Centeno JA, Finkelman RB, Fuge R, Lindh U, Smedley P, eds. Essentials of Medical Geology: Revised Edition. Dordrecht: Springer, 2013.


Serum Zinc and Copper Levels in Autistic Children

NeuroReport 25 (15) 2014In collaboration with Chinese researchers, Geir Bjørklund investigated the serum levels of zinc (Zn) and copper (Cu) in 60 Chinese children with autism (48 boys, 12 girls) and a control group of 60 healthy sex-matched and age-matched individuals. The researchers also evaluated the severity of autism using the Childhood Autism Rating Scale (CARS) score. The mean serum Zn levels and Zn/Cu ratio in the study were significantly lower in the autistic children compared with the control group (P<0.001). At the same time were the serum Cu levels significantly higher in the autistic children compared with the control group (P<0.001). It was in the study found a significant negative association between the Zn/Cu ratio and CARS scores (r=-0.345, P=0.007). 

The original article is published in NeuroReport (2014; 25 (15): 1216–1220). Bjørklund is founder and president of Council for Nutritional and Environmental Medicine (CONEM).


Si-Ou Li, Jia-Liang Wang, Geir Bjørklund, Wei-Na Zhao, and Chang-Hao Yin

Serum copper and zinc levels in individuals with autism spectrum disorders

Neuroreport 2014; 25 (15): 1216-1220



Trace elements play a critical role in the pathogenesis of autism spectrum disorders (ASD). The aim of this study was to investigate the serum levels of zinc (Zn) and copper (Cu) in Chinese children with ASD. Sixty patients (48 males, 12 females) diagnosed with ASD and 60 healthy sex-matched and age-matched control participants were assessed for serum Zn and Cu content at admission. The severity of ASD was also evaluated using the Childhood Autism Rating Scale (CARS) score. The results indicated that the mean serum Zn levels and Zn/Cu ratio were significantly lower in children with ASD compared with normal cases (P<0.001, respectively), whereas serum Cu levels were significantly higher (P<0.001). There was a significant negative association between Zn/Cu and CARS scores (r=-0.345, P=0.007). On the basis of the receiver operating characteristic curve, the optimal cut-off value of serum levels of Zn/Cu as an indicator for an auxiliary diagnosis of autism was projected to be 0.665, which yielded a sensitivity of 90.0% and a specificity of 91.7%; the area under the curve was 0.968 (95% confidence interval, 0.943-0.993). In conclusion, these results suggested an association between serum levels of Zn and Cu and ASD among Chinese patients, and the Zn/Cu ratio could be considered a biomarker of ASD.