SHE-Net - Outcome of the second workshop

Organic Contaminants and Human Health

The second workshop was held at the Newcastle University over two days from 29 – 30 January 2008. The purpose of the meeting was to consider the assessment of risk to human health from environmental contaminants. The twenty eight attendees were predominantly scientists (including toxicologists) with academic and government backgrounds. The group also included representatives of local government who were able to make a valuable contribution to discussions particularly regarding the practical difficulties of relating contaminated land to human risk.

The format for the workshop was a series of five 20-30 minute presentations, each with a short initial response from another speaker, followed by a session of questions and open discussion. Four of these took place on the first day of the workshop. At the beginning of the second day, all members of the group were asked to put forward 2-3 key items they had noted from the first day. These were briefly reviewed and categorised under three topics. Following a final presentation, the workshop was divided into three breakout groups (communication, bioaccessibility and toxicology), each given a separate topic to discuss in more detail. The workshop was concluded with the feedback from the breakout groups.

Presentations

The presentations covered a wide range of issues in relation to the impact of land contamination on human health, from the difficulties of establishing meaningful regulations and procedures, through the practicality of applying these, to the very detailed and precise science that can be used to generate the necessary supporting information.

  • An overview of HPA's activities and policies on contaminated land and human health risk assessment and future research priorities. Raquel Duarte-Davison (Chemical Hazards and Poisons Division, Health Protection Agency).
  • Exposure of Humans to Persistent Organic Pollutants (POPs): What is the Relevance of Soil? Olaf Paepke (Ergo Research Laboratory). 
  • Health risk assessment for oral exposure to PAH mixtures. Stuart Creton (Toxicology Unit,Food Standards Agency).
  • In-vitro bioaccessibility studies of PAHs from soil. Renli Ma (School of Applied Sciences, Northumbria University).
  • Difficulties of assessing health risks. David Bell (School of Biology, University of Nottingham). Discussion

When the group was asked, on the second morning, to reflect on the presentations from the previous day, a number of recurrent themes came out. These were discussed in more detail in the final breakout sessions.

Communication

There was a fairly strong consensus that social science had an important role to play in finding ways to communicate risk. There was some discussion of how social science might be incorporated into a 'hard' science team. This was needed to help in addressing the problems that different audiences will react to information in very different manners and that the perception and acceptance of risk will differ between individuals. Added to this, it was felt that different levels of trust existed depending on the source of information. There appeared to remain some tension about when and how scientists and social scientists could best work together in these situations. Even amongst the workshop attendees there were differences in opinion in that some felt that social scientists should help to translate numbers for communication purposes whereas others preferred a more integrated way of working between them.

Terminology, especially in the case of negative media coverage, could influence reaction, for example 'contaminated' land sending a more negative message than 'brownfield'.

The quantification and communication of uncertainty was seen as a particular challenge.

Previous research into communities living with 'risk' (Sellafield, Teesside) were noted and a number of research areas were suggested, although potential funding sources were not clear:

  • Study of ongoing risk communication exercises in relation to Thames Gateway and Olympic sites development, as well as case studies on other specific projects.
  • Preparation of policy and guidance documents. Development of common, clear and appropriate language (covering technical, statistics, social science) that is comprehensible to the general public without being over-simplified

Toxicology

Much discussion centred on dioxins and PAHs as these were covered in presentations and tend to be among the more commonly reported organics. Particular reference was made to the 'benzo(a)pyrene problem', which arose because the SGV derived by the current system was below the common background level in many areas.On the other hand, there was also concern that using BaP as a marker for risk assessment may not be giving a complete picture, especially at sites where there are high levels of non-genotoxic compounds such as naphthalene.

More generally, there was a sense that the system for deriving SGVs needed a thorough review and, especially, the acceptable health criteria might need challenging.Raquel, in her presentation, had explained that this was a DEFRA policy lead but there was a view that DEFRA may not feel able to make the necessary decisions on what was acceptable as a risk to human health.

In relation to dioxins, as well as a need for a cheap and easy method for measuring them, suggestions were made for further study:

  • modelled exposure versus actual
  • respiratory uptake and effects
  • toxicity of non-dioxin-like PCBs (most work has focused on dioxins and dioxin-like PCBs)

More generally, questions to be further considered included:

  • What are the main drivers for risk (is a systematic literature needed)?
  • Are we asking the right questions to COT/COC?
  • Is it possible to combine toxicological and epidemiological studies in order to assess toxicity and exposure together?
  • Is it possible to assess the level of 'conservatism' applied in setting environmental standards?
  • Is it possible to assess the toxicity of mixtures or 'unknowns' in contaminated soil?

Bioaccessibility

Although a very specific aspect, bioaccessibility was of great interest and it raised a number of issues, especially in relation to its role in actual exposure. There were questions about the reliability and robustness of methods and whether these should be standardised – and whether they should be different for metals and organics. The importance of soil type and the effects of pollutant ageing in soil were also raised. Other questions included whether bioaccessibility is already accounted for in toxicity testing, what physiological differences were there between the adult and child receptor, how individual sensitivities and variations in gut function should be taken into account and whether derivatives and (soil/plant) metabolites should be tested.

Participants

 

Organising Committee

Lindsay Bramwell

Newcastle University

Chris Collins

University of Reading

Raquel Duarte-Davison

Health Protection Agency

Ian Martin

Environment Agency

David Mortimer

Food Standards Agency

Tanja Pless-Mulloli

Newcastle University

George Shaw

Nottingham University

 

Invited Experts

Janet Charlton               

Gateshead Council

Stuart Creton

Food Standards Agency

Michael Dunn

Newcastle University

Adrienne Dunne

Health Protection Agency

David Bell

Nottinham University

Jane Entwistle

Newcastle University

Alwyn Fernandes

Central Science Laboratory

Faith Goodfellow

Health Protection Agency

Stuart Harrad

University of Birmingham

Phil Hartley

Newcastle University

Sue Hodgson

Newcastle University

Karen Johnson

Durham University

Shona Kelly

Nottingham University

Renli Ma

Northumbria University

Caroline McCaffrey

Land Quality Management

Elaine Mutch

Newcastle University

Mike Poremba

Gateshead Council

Arnout Standaert

Vito, Belgium

Faith Williams

Newcastle University

Jo Wragg

British Geological Survey

 

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