SEGH Articles

Application of geochemical signatures of shale in environmental pollution and human health assessment in South East Nigeria

15 June 2011
Therese Ntonzi Nganje describes her experience through a Commonwealth Scholarship scheme on connecting Nigerian and UK scientists.

This work contained activities during the period of my Commonwealth Scholarship Commission Fellowship (NGCF-2009-154) tenable held at the University of the West of Scotland October 2009- April 2010 under the supervision of Professor Andrew Hursthouse.

Areas underlain by shale rock in some parts of south-eastern Nigeria were investigated to ascertain the degree of environmental pollution by potential toxic trace element and the possible impact on human health.   A control area underlain by sandstone was also investigated as a known naturally low potentially toxic trace element area. Shales, especially the black variety, are natural geological sources of potentially toxic trace elements such as As, Cd, U, Mo, Cu, Ni, Hg among others, which are known to influence human health. The aim of this work was to primarily assess the effect of shale on the quality of the environment (soil, edible crop plants and water), evaluate the exposure pathways of the toxic trace elements and their implications on the health of humans. Samples of food, soil and drinking water were collected and transported under licence to the  

The water and soils and crop plants materials after the necessary treatment were digested with aqua regia in a hot block and were analyzed for both major and trace metals contents using Inductively Coupled Plasma Emission Spectrometry (ICP - OES) and Inductively Coupled Plasma Mass Spectrometry (ICP - MS) techniques. The anions in the water samples were determined by means of ion chromatography. Water physical parameters such as pH and conductivity were determined in-situ in the field. Also, soil parameters such as pH, total organic carton (TOC) as well as particle size were determined using standard methods.

The full results of the work are in various stages of preparation for publication and will include assessment to:

  • Allow comparison with existing global soil/plant/water data bases.
  • Establish the relationship between micronutrients and trace elements in soils and plants and possible implications to the health of humans in the area of study.
  • It is anticipated that this will provide a guide for policy analysis, environmental and health management decisions in the rapid urbanizing environment of Calabar and environs where my home University is located.

In addition, during my Fellowship, I was able to update and acquire new analytical skills and support to enable me to obtain a tenured position and scientific leadership in the area of Environmental Geochemistry at the University of Calabar (Nigeria). 


Activities included typical staff induction and orientation activities, advanced lecture courses in analytical techniques and measurement processes, seminars on environmental geochemistry - including iodine deficiency as well as research funding guidance. I also met many researchers, academics and technicians from Universities and regulatory organisations in the local area and had contact with other Commonwealth Fellows in the UK. I also had the opportunity to supervise UWS students in practical lab work.

All these activities were very relevant to my research at UWS as well as for my future career back in Nigeria as I am acquainted with the recent advances and analytical techniques in the area of environmental geochemistry and health of humans

My research stay in Scotland and UK has been very joyous, beneficial and successful as can be seen from the above report. The enabling environment to carry out this work to a successful completion was due to the receptive, friendly and accommodating people I met within and out of UWS.


I would like to thank Prof Andrew Hursthouse for accepting to host me, supervision and guidance, the University of the West of Scotland for access to facilities at the School of Science, the Commonwealth Scholarship Commission and British Council for funding and for their support prior to my visit and during the period of my fellowship and the authorities of the University of Calabar for the nomination and granting a study leave for me to take up the fellowship. The contributions of my head of department, Prof Aniekan Edet and colleague, Prof CS Okereke, SEGH and Dr Michael Watts of the British Geological Survey in UK for finding me a host institute are appreciated. The assistance provided in various aspects of the research work by Dr Simon Cuthbert, Dr John Hughes, Mr David Wallace, Mr Charlie McGuinnes, Ms Margaret Train and Natalie Dickson are also appreciated.

Finally my sincere and special thanks to Mr David Stirling for skills acquired and updated in the use of ICP-AES and ICP-MS and Mr Iain Mclellan for skills updated in the determination of some soil bulk parameters in soils.

Dr. Therese Ntonzi Nganje, University of Calabar, Nigeria

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

  • Membrane fouling control by Ca 2+ during coagulation–ultrafiltration process for algal-rich water treatment 2019-04-16


    Seasonal algal bloom, a water supply issue worldwide, can be efficiently solved by membrane technology. However, membranes typically suffer from serious fouling, which hinders the wide application of this technology. In this study, the feasibility of adding Ca2+ to control membrane fouling in coagulation–membrane treatment of algal-rich water was investigated. According to the results obtained, the normalized membrane flux decreased by a lower extent upon increasing the concentration of Ca2+ from 0 to 10 mmol/L. Simultaneously, the floc particle size increased significantly with the concentration of Ca2+, which leads to a lower hydraulic resistance. The coagulation performance is also enhanced with the concentration of Ca2+, inducing a slight osmotic pressure-induced resistance. The formation of Ca2+ coagulation flocs resulted in a looser, thin, and permeable cake layer on the membrane surface. This cake layer rejected organic pollutants and could be easily removed by physical and chemical cleaning treatments, as revealed by scanning electron microscopy images. The hydraulic irreversible membrane resistance was significantly reduced upon addition of Ca2+. All these findings suggest that the addition of Ca2+ may provide a simple-operation, cost-effective, and environmentally friendly technology for controlling membrane fouling during coagulation–membrane process for algal-rich water treatment.

  • Evaluation of the raw water quality: physicochemical and toxicological approaches 2019-04-13


    Environmental degradation has increased, mainly as a result of anthropogenic effects arising from population, industrial and agricultural growth. Water pollution is a problem that affects health, safety and welfare of the whole biota which shares the same environment. In Goiânia and metropolitan region, the main water body is the Meia Ponte River that is used for the abstraction of water, disposal of treated wastewater and effluents. In addition, this river receives wastewater from urban and rural areas. The aim in this present study was to evaluate the quality of raw water by some physical, chemical and toxicological tests. The physicochemical results found high levels of turbidity, conductivity, aluminum, phosphorus and metal iron, manganese, copper and lithium when compared to the standards of the Brazilian legislation. The values found of toxicity demonstrated a high degree of cytotoxicity and genotoxicity. Therefore, it was concluded that the Meia Ponte River has been undergoing constant environmental degradation, causing the poor quality of its waters. Thus, measures for the prevention and recovery should be adopted for the maintenance of the Meia Ponte River.

  • Review of the nature of some geophagic materials and their potential health effects on pregnant women: some examples from Africa 2019-04-11


    The voluntary human consumption of soil known as geophagy is a global practice and deep-rooted in many African cultures. The nature of geophagic material varies widely from the types to the composition. Generally, clay and termite mound soils are the main materials consumed by geophagists. Several studies revealed that gestating women across the world consume more soil than other groups for numerous motives. These motivations are related to medicinal, cultural and nutrients supplementation. Although geophagy in pregnancy (GiP) is a universal dynamic habit, the highest prevalence has been reported in African countries such as Kenya, Ghana, Rwanda, Nigeria, Tanzania, and South Africa. Geophagy can be both beneficial and detrimental. Its health effects depend on the amount and composition of the ingested soils, which is subjective to the geology and soil formation processes. In most cases, the negative health effects concomitant with the practice of geophagy eclipse the positive effects. Therefore, knowledge about the nature of geophagic material and the health effects that might arise from their consumption is important.