mercoledì 14 settembre 2016

Segnalazioni da Science for Environment Policy, Issue 468

Chemicals are everywhere and new substances are regularly being introduced to the market. However, only some pose a risk to the environment. How do we decide which of them to monitor? A new study using a database of chemicals found in fish in the Baltic Sea has assessed which chemicals are commonly monitored. The researchers suggest that monitoring is biased towards known, already regulated hazardous chemicals, and recommend changes to address other chemicals.
Although chemicals have improved people’s quality of life in many ways, they have, in some cases, put the health of ecosystems and of people at risk. To protect the environment, the EU’s REACH regulation requires all substances for which over 1 tonne is produced in (or imported to) the EU every year to be registered. Under REACH, the hazards posed by registered substances to human health and the environment are evaluated, and restrictions on placing them on the market and on their use are imposed if appropriate.
In order to enable sound management of chemicals, with the aim of reducing the risks associated with their use, their effects in the environment should be known and their occurrence should be monitored. However, it is not feasible to do this for the millions of chemicals in use. It is, therefore, important to prioritise the chemicals of highest concern — a major challenge currently facing regulatory bodies.
This study investigates how chemicals are prioritised for environmental analysis, using the Baltic Sea as a case study. The Baltic Sea is heavily polluted both by chemicals currently emitted, such as certain pharmaceuticals, and also by ‘legacy’ pollutants — i.e. pollutants released extensively years ago, but still of concern due to their persistence and hazardous properties.
To investigate which of these chemicals have been analysed (not specifically for regulatory purposes), the researchers looked at which chemicals were detected in Baltic Sea fish between 2000 and 2012. The focus on fish was for several reasons, including that contamination of fish in the Baltic Sea is a well-known and serious problem, which has led to restrictions on the European market in the trading of herring caught in the Baltic Sea, and that herring, a prominent fish species in the Baltic Sea, is very lipid rich, which facilitates the detection of organic pollutants in its tissue. The researchers collected data from screening programmes in Sweden, which borders the Baltic Sea, and from scientific journals.
In total, 105 different substances/groups of substances were analysed in Baltic Sea fish. The most studied substances were polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) (more commonly known as dioxins), and polychlorinated biphenyls (PCBs), another type of persistent organic pollutant (POP). POPs were by far the most studied substances; almost three quarters (72%) of all analyses were related to a POP-type substance. The majority (87%) of the analyses focused on the same 20% of substances, and almost half of substances were analysed only once.
Next, the researchers determined how many of these chemicals are regulated under the following:
  • Regulation EC 1272/2008 on classification, labelling and packaging (CLP) of substances and mixtures, which provides hazard information on chemicals.
  • The Stockholm Convention (Annexes A, B and C) — an international agreement to protect human health and the environment from POPs.
  • Regulation EC 1907/2006 concerning the registration, evaluation, authorisation and restriction of chemicals (REACH), which provides two important risk-management measures: authorisation and restriction:
  • Directive 2008/105/EC (as amended by Directive 2013/39/EU) on environmental quality standards (EQS). This Directive sets EQS in EU waters for a list of priority substances identified as posing a significant risk to the environment, or to human health via the environment, with the aim of achieving good chemical status.
More than two thirds of substances (70%) were covered by at least one regulation, or self-classified by industry according to CLP environmental hazard criteria. Some of the non-regulated chemicals included certain metals, perfluorinated compounds (present in water-resistant materials and flame retardants), phenolic substances (widely used in industry) and phthalates (used to make plastics more flexible), although many chemicals in these groups are regulated.
Overall, the results show that the majority of analyses of fish in the Baltic Sea are focused on a small number of already regulated chemicals. Although regulated and some other known hazardous chemicals pose a high risk, the bias towards them could be diverting policymakers from identifying risks posed by other toxic chemicals.
The researchers suggest several ways of improving this situation, including using non-target screening techniques, such as chromatography combined with high-resolution mass spectrometry, which uses a more open-ended approach to screening for pollutants and can detect not only known hazardous chemicals (traditionally detected by using reference substances) but also potentially overlooked harmful chemicals. The researchers also recommend using biological tools, such as biomarkers, which measure the toxicity of chemicals via the physiological effects they have on organisms, such as effects on growth, reproduction or gene expression1.
They also say that more open communication between regulatory activities, such as between risk assessment under REACH and monitoring under the Water Framework Directive, could be beneficial. Finally, they recommend that environmental agencies consider the chemicals contained in consumer products as emerging pollutants. They say these products are a major source of toxic substances, but are covered to a limited extent by current regulation.
As this study was limited to analyses on fish, only chemicals with the potential to bio-accumulate are represented in the results. It is possible that other chemicals have been monitored in other types of study, such as in studies that sample water directly.
1. For more information on effect-based biological tools, see the European Commission’s 2014 Technical Report on Aquatic Effect-Based Monitoring Tools: https://circabc.europa.eu/sd/a/0d78bbf7-76f0-43c1-8af2-6230436d759d/Effect-based%20tools%20CMEP%20report%20main%2028%20April%202014.pdf
Source: Sobek, A., Bejgarn, S., Rudén, C., & Breitholtz, M. (2016). The dilemma in prioritizing chemicals for environmental analysis: known versus unknown hazards. Environmental Science: Processes & Impacts, 18(8): 1042-9 DOI: 10.1039/c6em00163g. This study is free to view at http://pubs.rsc.org/en/content/articlepdf/2016/em/c6em00163g.
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A new methodology for mapping the global distribution of drought risk has been proposed, which should provide guidance on which locations should be further assessed to improve drought preparedness and management policies.
The European Commission estimates that the damage caused by drought in Europe over the past 30 years has cost at least €100 billion. Moreover, the European Environment Agency has recorded a doubling of the annual average economic impact of droughts across the continent between 1976 and 1990 and between 1991 and 2006. Similar trends can be found around the world.
There is a developing movement to reduce this global threat by moving away from a reactive, crisis-management approach to drought and towards improved drought resilience. This has been supported by the United Nations Office for Disaster Risk Reduction1 (UNISDR) and the World Meteorological Organization2. In order to promote such resilience, it is necessary to identify the areas that are most at risk, so that resources can be targeted at improving infrastructure and general preparedness where it is most needed. A recent study presents a data-driven approach to mapping the global patterns of drought risk, with the intention of identifying regions that would benefit from more detailed local assessments. This endeavour was carried out under the EU-funded HELIX3 project, as well as the EUROCLIMA4 regional cooperation programme between the EU and Latin America.
The researchers characterise drought risk as the probability of negative outcomes arising from interactions between drought hazard (potential for occurrence of future drought events), exposure (the scale of the total populations and associated assets in areas prone to drought) and vulnerability (propensity for assets, etc. to be damaged by drought), and use the equation: Risk = Hazard × Exposure × Vulnerability.
Based on these three independent determinants, they produce a value of drought risk, which is then used to determine a risk ranking of the areas being assessed. First, in order to validate the outcomes of their approach, the team evaluated the performance of exposure and vulnerability models and assessed the spatial distribution of drought hazard and risk at a range of scales. They used numerous pre-processed data sets at different spatial resolutions, in total covering approximately 67% of the earth’s total landmass and excluding particularly cold or arid areas, for which measures of drought are not useful.
The outcome is a global map of drought risk, calculated at a sub-national administrative level that allows for better coordination within and between different levels of government — from local to regional scales. The team then statistically evaluated the validity of their results by comparing their empirical performance with the outputs of alternative models, similar to the UN’s Human Development Index. The results of the team’s validation suggest that their proposed models of exposure and vulnerability are more robust, consistent and stable than alternative composite measures. They, therefore, suggest that their map could represent an important tool for policymakers in implementing drought policy. Specifically, their findings indicate that the growth of regional exposure in recent years is the key driver of drought risk, with less significant roles being played by hazard and vulnerability. Climate change projections look set to intensify this problem.
Drought risk appears to be higher for areas that are densely populated and exploited for crop production and livestock farming, such as Central Europe. The researchers suggest that regional drought-risk management in such areas would benefit from improvement of irrigation and water-harvesting systems, as well as from the diversification of regional economies, which would reduce their dependence on agriculture.
The researchers make it clear that their approach is top-down and data-driven, meaning it can be biased by uncertainties and errors in the global input values. They, therefore, emphasise that bottom-up risk studies in potentially drought-prone regions should be used to complement their top-down approach.
1. Hyogo Framework for Action 2005-2015: Building the resilience of nations and communities to disasters, Extract from the final report of the World Conference on Disaster Reduction
2. Sivakumara, M.V.K, Stefanskib, R., Bazzac, M., Zelayad, S., Wilhitee, D., Rocha Magalhaes, A. (2014). High Level Meeting on National Drought Policy: Summary and Major Outcomes. Weather and Climate Extremes, 3: 126–132. DOI:10.1016/j.wace.2014.03.007.
3. High-End cLimate Impacts and eXtremes (HELIX) was supported by the European Commission under the Seventh Framework Programme: www.helixclimate.eu/home
4. EUROCLIMA is a regional cooperation programme between the European Union and Latin America: www.euroclima.org/en
Source: Carrão, H., Naumann, G. & Barbosa, P. (2016). Mapping global patterns of drought risk: An empirical framework based on sub-national estimates of hazard, exposure and vulnerability. Global Environmental Change, 39: 108–124. DOI:10.1016/j.gloenvcha.2016.04.012.
Contact: hugo.carrao@gmail.com
Read more about: Agriculture, Climate change and energy, Water

 

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