My research interest falls into three broad areas: understanding the combined effects of mixtures of environmental pollutants on human health and wildlife, developing strategies for handling mixtures in chemicals regulation, and dissecting the events important in hormonal carcinogenesis.
1. Understanding combination effects of mixtures
Not long ago, the topic of mixture effects of chemicals was deemed too difficult to be approached experimentally. There has been, and still is, a confusion of important terms and concepts in mixture toxicology, as well as experimental approaches. We have tried to understand mixture effects in terms of the toxicity of individual mixture components: Is it possible to predict accurately the effects of a mixture, when we have information about the toxicity of its components, and of the mixture ratio?
Another issue arising from the experimental mixture studies is: How many chemicals are humans or wildlife exposed to simultaneously, and which of these contribute substantially to a specific combination effect? We are currently pursuing this problem by investigating mixtures that are modelled on realistic exposure scenarios.
2. Regulatory strategies for dealing with mixtures
A new consensus is emerging that mixture effects should be the topic of chemicals risk assessment. Any strategy for dealing with combination effects has to address the question: Which chemicals should be grouped together to be subjected to mixtures risk assessment? There are at least two approaches to resolving this question: Firstly, those chemicals that humans and wildlife come into contact with simultaneously should be considered. Secondly, chemicals that can produce similar adverse outcomes should also be grouped together. Our team is engaged in developing viable, pragmatic grouping criteria for chemicals in mixture risk assessment.
3. Hormones and hormonal carcinogenesis
While it is clear that hormones play a role in cancers of the breast, prostate and testes, their precise involvement in the disease process is far from clear. Our team is interested in studying the details of cell division and differentiation, and the role that steroid hormones and other hormonally active chemicals play in these processes. Here, we are collaborating closely with Dr Elisabete Silva.
- European Commission, £650,000 (over 3.5 years, ending 2012) for research into antiandrogens and human reproductive health, CONTAMED (Grant agreement number 212502)
- Oak Foundation (Geneva, Switzerland), £219,000 (over two years, ending 2012) for a project entitled “Combined exposures to endocrine disrupters: bridging the gap between science and chemicals risk assessment and regulation”
- European Commission (DG Environment), £253,000 (over 20 months, ending 2011) for a State of the Art Assessment of Endocrine Disrupters
- Food Standards Agency, £153,000 (over two years, ending 2012) for a project investigating the mixture effects of benzimidazole pesticides, contract T10053
- European Commission, £150,000 (over 5 years, ending 2013) for research into combination effects of neurotoxic agents, ESNATS project
- European Food Standards Authority, £170,000 (over 1 year) for developing grouping criteria for pesticides that act by different modes of action (contract CFT/EFSA/PPR/2010/02)
- European Commission (DG Environment), £ 150,000 for a State of the Art Report on Mixture Toxicology (completed 2009)
- Food Standards Agency, £482,112 (over three years) to investigate combination effects of multi-components mixtures of endocrine active food contaminants, contract T01045 (completed 2009)
- Bioforce Ltd, Switzerland, £85,000 (over three years) for a PhD studentship on the hormonal effects of plant extracts (awarded jointly to Dr Deniz Tasdemir, Centre for Pharmacognosy, School of Pharmacy), (completed 2011)
- 2004 Bioforce Ltd, Switzerland granted £75,000 (over three years) for a PhD studentship on adverse reactions to herbal medicine products (awarded jointly to Prof Heinrich, Centre for Pharmacognosy, School of Pharmacy) , (completed 2010)
- European Commission awarded 1,371,667 Euros (over four years, extended to 4.5 years) for research on endocrine disrupters. EDEN - Endocrine Disrupters: Exploring Novel Endpoints, Exposure, Low-Dose- and Mixture-Effects in Humans, Aquatic Wildlife and Laboratory Animals (EU-project Contract No QLRT-2001-00603), (completed 2007)
- European Commission awarded 264,322 Euros (over three years) for research on combination effects of aquatic pollutants with oestrogenic activity. ACE – Analysing combination effects of mixtures of estrogenic chemicals in marine and freshwater organisms (EU-project Contract No. EVK1-CT-2001-00100), (completed 2004)
- 1999 JNICT, Programa Ciencia, Portugal, awarded £55,000 (over three years) for support of a PhD project on mixture effects of xenoestrogens (completed 2002)
Our work is beginning to have significant political impact at the European Union level: In 2008 the Danish Government charged us with organizing an international workshop on combination effects of chemicals (28-30 January 2009, Hornbaek, Denmark)
The outcomes of this workshop were taken forward by the Danish Government to the European Council and have contributed to the Decision of the European Council of Environment Ministers of December 2009 on combinations effects of chemicals.
In December 2007 the European Commission, DG Environment commissioned a State of the Art Report on Mixture Toxicology which a consortium under our leadership won by competitive tender. The report was completed in December 2009 and was explicitly referred to in the European Council decision on combination effects of chemicals.
Research grants and projects
- Mr Martin Scholze
- Dr Sibylle Ermler
- Dr Elisabete Silva
- Prof Susan Jobling
- Prof John Sumpter
- Dr Catherine Calvelli
- Dr Tamsin Runnalls
- Dr Asma Baig
- Dr Mark Scrimshaw
- Miss Joanne Mcphie
- Dr Svetlana Ignatova
- Visualise network