SEGH Articles

Emerging Contaminants in the environment – is there a risk to health?

12 August 2012
In Europe and North America, there has been a gradual decrease in common environmental contaminants (heavy metals such as lead, cadmium; persistent organic pollutants such as DDT, Dioxin, PAH’s) in the environment. Common environmental contaminants, however, remain a public health concern in developing countries and newly industrialised countries.


In Europe and North America, there has been a gradual decrease in common environmental contaminants (heavy metals such as lead, cadmium; persistent organic pollutants such as DDT, Dioxin, PAH’s) in the environment. This improvement is largely due to a concerted effort of stricter regulations with improved monitoring, cleaner industrial processes and increased public awareness. Common environmental contaminants, however, remain a public health concern in developing countries and newly industrialised countries.

As we experience a decline in the levels and point sources of common chemicals, the focus has now been on the chemicals which were previously not considered as contaminants. They are not geogenic or air-born but are mainly synthetic by nature and produced to offer a range of societal benefits. Unlike common contaminants, ‘emerging chemical contaminants’ mostly find their way to the environment via diffuse sources i.e. domestic, commercial, and industrial uses. In addition, the development of more sensitive and new analytical capabilities that allows scientist to identify contaminants which are typically present in ultra-low concentrations (parts per billion to parts per trillion). The low concentrations combined with a lack of toxicological evidence make hazard characterisation technically challenging and thus the regulatory standards, where available, tend to be less rigorous and are advisory rather than prescriptive. In some cases (e.g. flame retardants) there are difficulties in identifying safer alternatives even when new evidence emerges about the health risk from the currently used materials.

Some examples of emerging contaminants include: perfluorocarbons ((e.g. perfluorooctane sulfonate (PFOS)), perfluorooctanoic acid (PFOA)), pesticides residues/metabolites (e.g. metaldehyde), pharmaceuticals and personal care products (e.g. steroids and antibiotics, fragrances, cosmetics), nanomaterials (e.g. buckeyballs or fullerenes; carbon nanotubes). These chemicals or their parent products are being manufactured to improve the quality and safety or to increase the efficiency in industrial processes. By nature, they are intended to last long or be resistant to microbial degradation in the environment. For example, PFCs contains only carbon and fluorine bonded together in strong carbon­-fluorine bonds which made them chemically inert and thermally stable. When these chemicals (e.g. PFOS, antibiotics, steroids) are released to the public sewer system, conventional water treatment processes can do little to render them harmless and go unabated to enter the wider environment and biotic food chain as a pollutant.

Our knowledge to relate the presence of emerging chemicals in the environment with public health significance is still at its infancy. Bioassays with animal models indicate the potential for toxicity to humans if exposed to a very high doses but such high dose exposure is unrealistic when compared to typical environmental concentrations. Uncertainty, however, remains over the potential health impacts from a low level chronic exposure due to their persistence and bioaccumulative nature. Studies with ecological receptors e.g. with fish in streams contaminated by steroids have shown evidence of hormone disruption. There is also concern that elevated exposure to antibiotics in water could lead to disease-resistant strains of bacteria, reducing the effectiveness of the current class of drugs. For the human population, the limited data available suggests that there is a need for more “prospective cohort” type study to characterise the association between environmental exposure to these substances, appropriate biomarkers and measurable health outcomes.


Emerging chemicals should be a source of concern to ecological and public health in all parts of the world. In this era of financial constraint and interdependent/connected economies, there is a need for shared research programme and data-sharing to enhance analytical capacity to determine their environmental occurrence, fate and transport.  There is also a need for improved risk assessment tools to characterise the exposure and extrapolation of ecological risk to public health if relevant and appropriate. Regulatory policy should encompass emerging chemicals in their monitoring regime, and encourage safer alternatives, increased awareness and risk reduction programme. Societies like the SEGH can facilitate research consortia or a task force drawing from its international expertise to influence the relevant public policy and apply for research funding. Further information on emerging chemicals can be found in websites of various regulatory and public health organisations such as European Chemicals Agency, US EPA, ATSDR.    


Sohel Saikat, Health Protection Agency, UK.

Keep up to date

SEGH Events

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

  • Biochar-based constructed wetlands to treat reverse osmosis rejected concentrates in chronic kidney disease endemic areas in Sri Lanka 2017-12-01


    The objectives were to investigate the potential remedial measures for reverse osmosis (RO) rejected water through constructed wetlands (CWs) with low-cost materials in the media established in chronic kidney disease of unknown etiology (CKDu) prevalent area in Sri Lanka. A pilot-scale surface and subsurface water CWs were established at the Medawachchiya community-based RO water supply unit. Locally available soil, calicut tile and biochar were used in proportions of 81, 16.5 and 2.5% (w/w), respectively, as filter materials in the subsurface. Vetiver grass and Scirpus grossus were selected for subsurface wetland while water lettuce and water hyacinth were chosen for free water surface CWs. Results showed that the CKDu sensitive parameters; total dissolved solids, hardness, total alkalinity and fluoride were reduced considerably (20–85%) and most met desirable levels of stipulated ambient standards. Biochar seemed to play a major role in removing fluoride from the system which may be due to the existing and adsorbed K+, Ca+2, Mg+2, etc. on the biochar surface via chemisorption. The least reduction was observed for alkalinity. This study indicated potential purification of aforesaid ions in water which are considerably present in RO rejection. Therefore, the invented bio-geo constructed wetland can be considered as a sustainable, economical and effective option for reducing high concentrations of CKDu sensitive parameters in RO rejected water before discharging into the inland waters.

  • Medical geology of endemic goiter in Kalutara, Sri Lanka; distribution and possible causes 2017-12-01


    This study assesses the distribution of goiter in the Kalutara District, Sri Lanka in order to find causative factors for the occurrence of goiter even after the salt iodization. A questionnaire survey was conducted at the household level and at the same time iodine and selenium levels of the water sources were analyzed. Questionnaire survey results indicated the highest numbers of goiter patients in the northern part where the lowest were found in the southern sector which may be due to the presence of acid sulfate soils. Females were more susceptible and it even showed a transmittance between generations. Average iodine concentrations in subsurface water of goiter endemic regions are 28.25 ± 15.47 μg/L whereas non-goiter regions show identical values at 24.74 ± 18.29 μg/L. Surface water exhibited relatively high values at 30.87 ± 16.13 μg/L. Endemic goiter was reported in some isolated patches where iodine and selenium concentrations low, latter was <10 μg/L. The formation of acid sulfate soils in the marshy lands in Kalutara district may lead to transformation of biological available iodine oxidation into volatile iodine by humic substances, at the same time organic matter rich peaty soil may have strong held of iodine and selenium which again induced by low pH and high temperature were suggested as the instrumental factors in the endemic goiter in Kalutara district. Hence, geochemical features such as soil pH, organic matter and thick lateritic cap in the Kalutara goiter endemic area play a role in controlling the available selenium and iodine for food chain through plant uptake and in water.

  • Nickel accumulation in paddy rice on serpentine soils containing high geogenic nickel contents in Taiwan 2017-12-01


    We investigated the extractability of nickel (Ni) in serpentine soils collected from rice paddy fields in eastern Taiwan to evaluate the bioavailability of Ni in the soils as well as for demonstrating the health risks of Ni in rice. Total Ni concentrations in the soils ranged were 70.2–2730 mg/kg (mean, 472 mg/kg), greatly exceeding the natural background content and soil control standard in Taiwan. Available Ni concentration only accounts for <10% of total soil Ni content; 0.1 N HCl-extractable Ni was the more suitable index for Ni bioavailability in the soil to rice than was diethylenetriaminepentaacetic acid (DTPA)-extractable Ni. The accumulation ability of rice roots was much higher than that of its shoots; however, compared with those reported previously, our brown and polished rice samples contained much higher Ni concentrations, within the ranges of 1.50–4.53 and 2.45–5.54 mg/kg, respectively. On the basis of the provisional tolerable Ni intake for adults recommended by the World Health Organization (WHO), daily consumption of this rice can result in an excessive Ni intake.