SEGH Articles

Back to the Future: Brian E Davies (Past President)

08 April 2014
Should we reduce our emphasis on the toxic elements? Is it time to go back to the future?



In 1970, when SEGH began, we talked about many ideas: is aluminium involved in dementia?; is arsenic an essential element?; is chromium involved in Type 2 diabetes?; can the incidence of gastric cancer be related to copper and zinc in the environment? By 1982, when I organised SEGH, and its first conference, in Britain, priorities had changed to environmental metals and sometimes we now appear to be a pollution society.


Have we reached the end of the metals era? For example, lead. The danger to child mental development has been recognised and quantified: the role of hand dirt is understood, paint and petrol are lead free, government regulations are in place, the environmental chemistry of lead is broadly understood. New ideas are now more likely to come from the clinical rather than the earth sciences. Or, cadmium. Little epidemiological evidence has emerged that environmental cadmium is a significant health problem. The special problems in Asia are probably because of poor iron nutrition (Simmons et al., 2003).


Death from all causes in 2012 (England and Wales) was 489,274. Accidental poisoning by ‘noxious substances’ accounted for 1,416 (0.3%) in contrast with 8,367 (1.7%) alcohol related deaths. Malignant neoplasms and diseases of the circulatory system each represented 28.8% total deaths. Morbidity data are broadly similar.



For cardiovascular diseases magnesium is a cofactor for over 300 enzyme systems and is required for energy generation and glycolysis. Magnesium is involved in nerve conduction, muscle contraction, potassium transport, and calcium channels. An environmental geochemistry link is seen in reports that deaths from heart attacks are greater where drinking water is soft. We all drink some tap water if only in tea, coffee or diluted ‘squash’.

In the next SEGH conference I plan to present a paper giving results from a desk study to establish the plausibility of a hard/soft water effect. The daily Reference Nutrient Intake (RNI) for Mg is men = 12 mmol. Nationally, solid food, pus bottled water plus alcoholic drinks for men provide (mean) 10.62 mmol Mg or 89% RNI. Adding in tap water: reservoir water contributes little Mg (total Mg intake 88.9% RNI); (mean) aquifer water Mg raises total intake to 11.85 mmol (96.5% RNI); a very hard water (North Downs chalk) raises total intake to 50.3 mmol (419% RNI). A beneficial role for Mg in hard drinking water seems plausible.

A recent paper (McKinley et al., 2013) reported a relationship between environmental exposure to trace elements in soil and cancer across Northern Ireland. Copper is an integral part of the antioxidant enzyme, copper-zinc superoxide dismutase. Copper deficiencies in animals and crops in Britain are a well attested problem. Yet we know little about any link from soil to humans.

Much reliable health data can now be accessed over the internet. Perhaps it is time to return to some of the older unanswered questions in environmental geochemistry and health. Should we reduce our emphasis on the toxic elements? Is it time to go back to the future?

By Professor Brian E Davies:


McKinley, J. M., Ofterdinger, U., Young, M., Barsby, A., & Gavin, A. (2013). Investigating local relationships between trace elements in soils and cancer data. Spatial Statistics, 5, 25–41.

Simmons, R. W., Pongsakul, P., Chaney, R. L., Saiyasitpanich, D., Klinphoklap, S., & Nobuntou, W. (2003). The relative exclusion of zinc and iron from rice grain in relation to rice grain cadmium as compared to soybean: Implications for human health. Plant and Soil, 257(1).

Keep up to date

Submit Content

Members can keep in touch with their colleagues through short news and events articles of interest to the SEGH community.

Science in the News

Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

  • Improving arsenopyrite oxidation rate laws: implications for arsenic mobilization during aquifer storage and recovery (ASR) 2018-04-25


    Aquifer storage and recovery (ASR) and aquifer recharge (AR) provide technical solutions to address water supply deficits and growing future water demands. Unfortunately, the mobilization of naturally present arsenic due to ASR/AR operations has undermined its application on a larger scale. Predicting arsenic mobility in the subsurface during ASR/AR is further complicated by site-specific factors, including the arsenic mobilization mechanisms, groundwater flow conditions, and multi-phase geochemical interactions. In order to ensure safe and sustainable ASR/AR operation, a better understanding of these factors is needed. The current study thus aims to better characterize and model arsenic remobilization at ASR/AR sites by compiling and analyzing available kinetic data on arsenic mobilization from arsenopyrite under different aqueous conditions. More robust and widely applicable rate laws are developed for geochemical conditions relevant to ASR/AR. Sensitivity analysis of these new rate laws gives further insight into the controlling geochemical factors for arsenic mobilization. When improved rate laws are incorporated as the inputs for reactive transport modeling, arsenic mobilization in ASR/AR operations can be predicted with an improved accuracy. The outcomes will be used to guide groundwater monitoring and specify ASR/AR operational parameters, including water pretreatment requirements prior to injection.

  • Heavy metal exposure has adverse effects on the growth and development of preschool children 2018-04-25


    The purpose of this study was to investigate the associations between levels of lead (Pb), cadmium (Cd), chromium (Cr), and manganese (Mn) in the PM2.5 and blood and physical growth, and development parameters including birth length and weight, height, weight, body mass index (BMI), head circumference, and chest circumference in preschool children from Guiyu (e-waste exposure area) and Haojiang (the reference area). A total of 470 preschool children from Guiyu and Haojiang located in southeast coast of China were recruited and required to undergo physical examination and blood tests during the study period. Birth length and weight were obtained by birth records and questionnaire. Pb and Cd in both PM2.5 and blood were significantly higher in Guiyu than Haojiang. Remarkably, the children of Guiyu had significantly lower birth weight and length, BMI, and chest circumference when compare to their peers from the reference area (all p value < 0.05). Spearman correlation analyses showed that blood Pb was negatively correlated with height (r = −0.130, p < 0.001), weight (r = −0.169, p < 0.001), BMI (r = −0.100, p < 0.05), head circumference (r = −0.095, p < 0.05), and chest circumference (r = −0.112, p < 0.05). After adjustment for the potential confounders in further linear regression analyses, blood Pb was negatively associated with height (β = −0.066, p < 0.05), weight (β = −0.119, p < 0.001), head circumference (β = −0.123, p < 0.01), and chest circumference (β = −0.104, p < 0.05), respectively. No significant association between blood Cd, Cr, or Mn was found with any of our developmental outcomes. Taken together, lead exposure limits or delays the growth and development of preschool children.

  • Contamination characteristics of trace metals in dust from different levels of roads of a heavily air-polluted city in north China 2018-04-24


    Concentrations of eight trace metals (TMs) in road dust (RD) (particles < 25 μm) from urban areas of Xinxiang, China, were determined by inductively coupled plasma mass spectrometry. The geometric mean concentrations of Zn, Mn, Pb, As, Cu, Cr, Ni and Cd were 489, 350, 114, 101, 60.0, 39.7, 31.6, and 5.1 mg kg−1, respectively. When compared with TM levels in background soil, the samples generally display elevated TM concentrations, except for Cr and Mn, and for Cd the enrichment value was 69.6. Spatial variations indicated TMs in RD from park path would have similar sources with main roads, collector streets and bypasses. Average daily exposure doses of the studied TMs were about three orders of magnitude higher for hand-to-mouth ingestion than dermal contact, and the exposure doses for children were 9.33 times higher than that for adults. The decreasing trend of calculated hazard indexes (HI) for the eight elements was As > Pb > Cr > Mn > Cd > Zn > Ni > Cu for both children and adults.