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.

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

• Characteristics of PM 2.5 , CO 2 and particle-number concentration in mass transit railway carriages in Hong Kong 2017-08-01

### Abstract

Fine particulate matter (PM2.5) levels, carbon dioxide (CO2) levels and particle-number concentrations (PNC) were monitored in train carriages on seven routes of the mass transit railway in Hong Kong between March and May 2014, using real-time monitoring instruments. The 8-h average PM2.5 levels in carriages on the seven routes ranged from 24.1 to 49.8 µg/m3, higher than levels in Finland and similar to those in New York, and in most cases exceeding the standard set by the World Health Organisation (25 µg/m3). The CO2 concentration ranged from 714 to 1801 ppm on four of the routes, generally exceeding indoor air quality guidelines (1000 ppm over 8 h) and reaching levels as high as those in Beijing. PNC ranged from 1506 to 11,570 particles/cm3, lower than readings in Sydney and higher than readings in Taipei. Correlation analysis indicated that the number of passengers in a given carriage did not affect the PM2.5 concentration or PNC in the carriage. However, a significant positive correlation (p < 0.001, R 2 = 0.834) was observed between passenger numbers and CO2 levels, with each passenger contributing approximately 7.7–9.8 ppm of CO2. The real-time measurements of PM2.5 and PNC varied considerably, rising when carriage doors opened on arrival at a station and when passengers inside the carriage were more active. This suggests that air pollutants outside the train and passenger movements may contribute to PM2.5 levels and PNC. Assessment of the risk associated with PM2.5 exposure revealed that children are most severely affected by PM2.5 pollution, followed in order by juveniles, adults and the elderly. In addition, females were found to be more vulnerable to PM2.5 pollution than males (p < 0.001), and different subway lines were associated with different levels of risk.

• Comparison of chemical compositions in air particulate matter during summer and winter in Beijing, China 2017-08-01

### Abstract

The development of industry in Beijing, the capital of China, particularly in last decades, has caused severe environmental pollution including particulate matter (PM), dust–haze, and photochemical smog, which has already caused considerable harm to local ecological environment. Thus, in this study, air particle samples were continuously collected in August and December, 2014. And elements (Si, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Cd, Ba, Pb and Ti) and ions ( $${\text{NO}}_{3}^{-}$$ , $${\text{SO}}_{4}^{2-}$$ , F, Cl, Na+, K+, Mg2+, Ca2+ and $${\text{NH}}_{4}^{+}$$ ) were analyzed by inductively coupled plasma mass spectrometer and ion chromatography. According to seasonal changes, discuss the various pollution situations in order to find possible particulate matter sources and then propose appropriate control strategies to local government. The results indicated serious PM and metallic pollution in some sampling days, especially in December. Chemical Mass Balance model revealed central heating activities, road dust and vehicles contribute as main sources, account for 5.84–32.05 % differently to the summer and winter air pollution in 2014.

• Annual ambient atmospheric mercury speciation measurement from Longjing, a rural site in Taiwan 2017-08-01

### Abstract

The main purpose of this study was to monitor ambient air particulates and mercury species [RGM, Hg(p), GEM and total mercury] concentrations and dry depositions over rural area at Longjing in central Taiwan during October 2014 to September 2015. In addition, passive air sampler and knife-edge surrogate surface samplers were used to collect the ambient air mercury species concentrations and dry depositions, respectively, in this study. Moreover, direct mercury analyzer was directly used to detect the mercury Hg(p) and RGM concentrations. The result indicated that: (1) The average highest RGM, Hg(p), GEM and total mercury concentrations, and dry depositions were observed in January, prevailing dust storm occurred in winter season was the possible major reason responsible for the above findings. (2) The highest average RGM, Hg(p), GEM and total mercury concentrations, dry depositions and velocities were occurred in winter. This is because that China is the largest atmospheric mercury (Hg) emitter in the world. Its Hg emissions and environmental impacts need to be evaluated. (3) The results indicated that the total mercury ratios of Kaohsiung to that of this study were 5.61. This is because that Kaohsiung has the largest industry density (~60 %) in Taiwan. (4) the USA showed average lower mercury species concentrations when compared to those of the other world countries. The average ratios of China/USA values were 89, 76 and 160 for total mercury, RGM and Hg(p), respectively, during the years of 2000–2012.