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: ewartdavies@gmail.com


References

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

  • Earthworms and vermicompost: an eco-friendly approach for repaying nature’s debt 2020-01-23

    Abstract

    The steady increase in the world’s population has intensified the need for crop productivity, but the majority of the agricultural practices are associated with adverse effects on the environment. Such undesired environmental outcomes may be mitigated by utilizing biological agents as part of farming practice. The present review article summarizes the analyses of the current status of global agriculture and soil scenarios; a description of the role of earthworms and their products as better biofertilizer; and suggestions for the rejuvenation of such technology despite significant lapses and gaps in research and extension programs. By maintaining a close collaboration with farmers, we have recognized a shift in their attitude and renewed optimism toward nature-based green technology. Based on these relations, it is inferred that the application of earthworm-mediated vermitechnology increases sustainable development by strengthening the underlying economic, social and ecological framework.

    Graphic abstract

  • Plasticizers and bisphenol A in Adyar and Cooum riverine sediments, India: occurrences, sources and risk assessment 2020-01-23

    Abstract

    Adyar and Cooum, the two rivers intersecting Chennai city, are exposed to serious pollution due to the release of large quantities of dumped waste, untreated wastewater and sewage. Sediments can act as repository for emerging organic contaminants. Hence, we have monitored the occurrence and risk associated with plasticizers [six phthalic acid esters (PAEs), bis(2-ethyl hexyl adipate) (DEHA)] and bisphenol A (BPA) in surface riverine sediments of Adyar and Cooum rivers from residential/commercial, industrial and electronic waste recycling sites. Σ7plasticizers (PAEs + DEHA) in the Adyar riverine sediment (ARS) and Cooum riverine sediment (CRS) varied between 51.82–1796 and 28.13–856 ng/g, respectively. More than three-fourth of Σ7plasticizers came from bis(2-ethylhexyl) phthalate (DEHP), in accordance with the high production and usage of this compound. BPA varied between 10.70–2026 and 7.58–1398 ng/g in ARS and CRS, respectively. Average concentrations of plasticizers and BPA were four times higher in electronic waste (e-waste) recycling sites when compared with industrial and residential/commercial sites. BPA and DEHP showed a strong and significant correlation (R2 = 0.7; p < 0.01) in the e-waste sites thereby indicating common source types. Sites present at close proximity to raw sewage pumping stations contributed to 70% of the total BPA observed in this study. For the derived pore water concentration of plasticizers and BPA, the ecotoxicological risk has been found to be higher in ARS over CRS. However, sediment concentrations in all the sites of ARS and CRS were much below the recommended serious risk concentration for human (SRChuman) and serious risk concentration for ecotoxicological (SRCeco).

  • Distribution of metal(loid)s in particle size fraction in urban soil and street dust: influence of population density 2020-01-18

    Abstract

    Assessment of street dust is an invaluable approach for monitoring atmospheric pollution. Little information is available on the size distribution of contaminants in street dusts and urban soils, and it is not known how the population density would influence them. This research was carried out to assess the size distribution of trace metal(loid)s in street dust and urban soil, and to understand how population density might influence the size-resolved concentration of metal(loid)s. Three urban areas with a high, medium and low population density and a natural area were selected and urban soil and street dust sampled. They were fractionated into 8 size fractions: 2000–850, 850–180, 180–106, 106–50, 50–20, 20–10, 10–2, and < 2 µm. The concentration of Pb, Zn, Cu, Cd, Cr, Ni, As, and Fe was determined, and enrichment factor and grain size fraction loadings were computed. The results indicated that the concentration of Pb, Zn, Cu, Cd, and Cr was highly size dependent, particularly for particles < 100 µm, especially for street dust. Low concentrations of Ni and As in street dust and urban soil were size and population density independent. Higher size dependency of the metals concentration and the higher degree of elemental enrichment in the street dust fractions than the urban soils indicate higher contribution of human-induced pollution to the dust. Findings also confirm the inevitability of size fractionation when soils or dusts are environmentally assessed, particularly in moderately to highly polluted areas. Otherwise, higher concentrations of certain pollutants in fine-sized particles might be overlooked leading to inappropriate decisions for environmental remediation.