Getting the measure of success

Pollution is a global issue, with inter-connected environmental and health consequences. Outdoor air pollution at current levels in the UK makes a significant contribution to mortality in the UK. It has a greater burden, in terms of estimated total population survival time, than the mortality impacts of environmental tobacco smoke or road traffic accidents¹.

Water polluted with heavy metals from industrial processes can result in birth defects or cause cancer due to their carcinogenic nature. Microbial pollutants can result in infectious diseases through drinking contaminated water and, although the quality of our water has improved dramatically over the past few decades, only 27% of our water-bodies in England are currently classified as being of ‘good status’ under new standards set down by the EU Water Framework Directive².

The European Union has some of the world's highest environmental standards, which have been developed over decades. Through regulations and directives, issues such as acid rain, the thinning of the ozone layer, air quality, noise pollution, waste and water pollution are tackled.

The responsibility for implementing this through, for example, monitoring known pollutants and developing measures to improve the state of the environment is usually devolved to member states. This can prove challenging as limits are often set at very low levels, particularly when there are safety or health implications. Often there is a lack of suitable measurement procedures in place when legislation is passed and targets are set, and it falls to member states to solve these challenges.

In its role as the UK’s designated National Measurement Institute (NMI) for chemical and bio-measurement, LGC plays a major role in solving these measurement challenges through research to develop new and improved measurement methods and measurement standards to underpin EU regulations.

For example, the European Water Framework Directive (WFD, Directive 2000/60/EC) prioritised hazardous substances to be monitored for their concentrations in water bodies to ensure they meet the Environmental Quality Standards (EQS) set for them within specified timelines. The aim is for all EU member states to achieve “good status” in most inland and coastal waters by 2015, to prevent deterioration and to achieve the progressive reduction of emissions, discharges and losses of a list of priority substances as well as the cessation of priority hazardous substances.

The accurate determination of critical pollutants in water samples is still challenging for many chemical laboratories due to the extremely low limits of quantification required. There is an urgent need to develop reference methods which can provide reference values to help field laboratories to validate their water quality monitoring methods and supporting a monitoring network in Europe³.

Taking one example, polybrominated flame retardants (PBDEs) are highlighted as hazardous pollutants as they have been shown to be carcinogenic in animal studies. They have also been shown to be bioaccumulative in mammals – including humans – and can concentrate in human blood, fat tissue, and breast milk. They are found in many everyday household items such as upholstered furniture, mattresses and other synthetic home textiles, and TV or computer equipment containing plastic casings, cables and circuit boards, acting as important flame retardants. However, these items often end up in landfill where potentially harmful levels of PBDEs can leach into rivers.

LGC scientists have developed traceable methods for the accurate determination of the total concentration and partitioning of PBDEs at Environmental Quality Standard levels (?PBDEs ? 0.5 ng/L) in support of the implementation of the WFD 2000/60/EC and daughter directives (e.g. 2009/90/EC). They used a gas chromatography-inductively coupled plasma-mass spectrometry (GC-ICP-MS) method to quantify the six target PBDE congeners (28, 47, 100, 99, 154 and 153). The method has been validated and a full uncertainty budget provided.

Methods to extract the target PBDEs from water samples based on liquid/liquid extraction were optimised using a model water system containing a high amount of organic colloids (humic acid) and PBDEs at the sub-nanogram per litre levels specified by the WFD. The method was applied successfully to environmental samples (lake and river waters), and the obtained uncertainties were well within those required by the WFD. The joint work of LGC with other partner metrology institutes have been published following peer review⁴.

Mercury is also a priority hazardous substance which features in several EU regulations including the WFD. It has many chemical forms, which are highly toxic to human, animal and plant health due to its ability to accumulate in terrestrial and aquatic bio-systems.

European member states are legally obliged to progressively reduce discharges, emissions and losses of mercury to zero within the next 20 years⁵. The use of mercury is being phased out in the UK for many applications, and is limited to a mass fraction of mercury in products of less than 1000 mg/kg in any current usage or new application. But despite these steps mercury is still entering the European environment in large amounts and, due to its ability to be transported in air over long distances, it is also entering via trans-boundary transport from other parts of the world. As a result, releases of mercury in other parts of the world are as important to Europeans as domestic emissions. Without improved pollution controls or other actions to reduce mercury emissions, levels are likely to be substantially higher in 2050 than they are today.

In a bid to halt the trend of rising mercury levels, more than 90 countries signed a treaty to limit mercury use and pollution at a United Nations conference in Kumamoto, Japan in 2013. The Minamata Convention on Mercury aims to curb emissions of the metal from power plants and other industrial facilities, and to limit its use in products from batteries and light bulbs to medical equipment.

But for nations to effectively cut mercury emissions, they need to be able to monitor levels of the metal in the environment. A three-year European-funded project involving LGC scientists has been launched to develop the capability for measuring mercury in environmental samples, including biota and air particulates. LGC’s role is to solve outstanding metrological challenges associated with isotope ratio measurements of mercury and mercury species in biota.

Mercury isotopic data can be used to understand mercury amount, distribution and environment cycling. This is the way mercury moves through and is re-used or re-absorbed in the environment – not just in terms of geographical location but also its chemical form (organic or inorganic), which organism it’s in or where else in the environment it is, i.e. river, soil, air.

LGC scientists aim to solve metrological challenges to ensure that the effects of sample preparation, introduction and instrumental parameters on mass discrimination in Hg isotope ratio measurements by multicollector ICP-MS are well understood accounted for. Special attention will be paid to the evaluation of the potential occurrence of mass-independent effects during sample storage, preparation and analysis.

It will also investigate the feasibility of novel sampling techniques, such as laser ablation, in combination with ICP-MS to rapidly monitor mercury distribution in environmental particulates collected on filters.

If successful, the project will help establish the metrological infrastructure for mercury measurements in environmental samples, needed for current and future legislation aimed at controlling mercury emissions and releases.

These are just two examples of projects that are strengthening the traceability of measurements that underpin legislation, regulation and standardisation. Europe’s 200 or so environmental laws cover a vast range of pollutants and as science discovery continues the lists of priority hazardous substances will no doubt grow. There is though a need to understand the risk associated with these pollutants through robust ecotoxicological work. The challenge set to analytical chemists is then very significant, often because the risk assessments are poor, and “safety margins” need to be incorporated, leading sometimes to unfeasibly low EQS values being proposed or set.

Additionally, many of the likely priority hazardous substances being put forward in the next few years will be of pharmaceutical origin, which adds a new dimension as these are beneficial to humans but may be harmful to the environment.

The EU has faced criticism for introducing legislation and setting targets that can be difficult to enforce but ultimately, in doing so, it is driving collaborative scientific innovation and discovery. The ambitious deadlines set for National Measurement Institutes around the world to develop traceable measurement methods and standards mean they are increasingly establishing multi-national collaborations with other scientists to share expertise, all with the goal of making the world a safer, cleaner place to live.