Waste management and public health: the state of the evidence

Protecting the health of the public

How can the epidemiological evidence be used in waste management strategies and practice to protect public health?

 

6.1          National policy

In its Waste Strategy, the government has stated that the protection of human health is one of the important objectives of its waste management strategy (DETR 2001): "We have long sought to protect the local environment and human health from the adverse effects of waste management through a comprehensive system of planning and pollution control legislation" (Section 3.5 DETR 2001). A key feature of the Framework Directive on Waste, 91/156/EEC, and the licensing system is "the objective of ensuring that waste is recovered or disposed of without endangering human health and without using processes or methods which could harm the environment" (Waste Strategy 2000 Section 3.36 DETR 2001).

The government issues guidance on how local authorities and the Environment Agency are to implement its policies. The Planning Policy Guidance Note 10 (DETR 1999) sets out the national planning framework for waste and states that the Government wishes to see decisions based on four key principles – the Best Practicable Environmental Option, regional self sufficiency, proximity principle, and the waste hierarchy.

6.2          Decision making in the face of uncertainty

6.2.1            Uncertainty

"The major problem in marrying policy and the science which informs it is that the timescales of the two never match. This is true almost by definition, since if there were sufficient science in place, then the problem of characterizing the scientific essentials of an issue is solved and policy formulation is then determined by consideration of other issues such as the social, economic and political aspects of the problem. Unfortunately, life is generally not this simple, and one often finds that there is insufficient scientific information compared with what ideally would be required." (Maynard & Howard 2000)

 

This overview of the scientific evidence exposes a high degree of uncertainty about the impact of waste management operations on health, which may or may not ever be resolved by further research. Despite the impressive amount of research and the high quality of many of the studies, the state of the evidence is such that, with a few exceptions (see section 5.7), no certain conclusions can be drawn.

 

6.2.2            Interpretations of the evidence

In the meantime, waste management decisions have to be made and the health of the public has to be protected. In theory, decision making should be based on a rigorous assessment of the scientific evidence. In reality, waste management decision making takes place in a highly charged political environment, with different interest groups driven by conflicting values and belief systems as well as by contrary interpretations of the same scientific evidence.

Decision makers have to proceed despite the uncertainty. The following case illustrates the dilemmas they face:

 

Wrexham County Borough Council initially granted Shanks Waste Services permission to install an electricity generating plant on its landfill site in 1994 but refused planning permission in 1999 when the company applied to change details of its plan. In the intervening years, local residents had raised concerns about possible health risks. The Council's planning committee was persuaded that there was not enough independent scientific evidence to show that fears about health risks were unfounded. Shanks appealed and at the subsequent inquiry, the Inspector over-ruled the planning committee's decision and granted the company permission to install the plant. The Inspector said that the Council should base their decisions on objective assessments, not on unfounded fears. As the emissions from the electricity generating plant would not exceed National Air Quality Standards and World Health Organisation levels, he could find no evidence to justify concerns about health impacts (Described in NSCA 2001). In other inquiries, fear of adverse health effects has been allowed as a material consideration but the weight given to it has varied. (Brian Cook, personal communication, September 2001.)

 

Both of the decisions in this case were based on reasonable interpretations of the same scientific evidence. Neither decision was more objective nor more correct than the other. Valid arguments could be made in defence of both the Council's decision and the Inspector's. Depending on the interpretation, different courses of action will result.

Informed debate has polarised into two plausible positions:

 

Position one

There is no evidence of significant harm to human health from waste management operations. No human activity is completely safe but compared to other environmental health hazards (e.g. vehicle traffic) or compared to other causes of ill health (e.g, poor diet, diseases), waste management operations are not a major public health concern.

An example of this position is taken by The National Society for Clean Air and Environmental Protection in its recent report on incineration. It concludes , "While we cannot discount effects resulting from the small quantities of some pollutants emitted by MSW (Municipal Solid Waste) incinerators where impacts may occur at background levels (e.g. dioxins) or where current standards (limit values) may be exceeded (e.g. nitrogen dioxide) the large number of other important sources of such pollutants suggest that these deserve a greater emphasis on regulatory control." (Farmer & Hjerp 2001)

 

Position two

Lack of evidence is not the same as evidence of lack of health impacts. Waste management methods may have a major impact on health but the limitations of the research make it impossible to determine whether this is the case.

An example of this position comes from the Greenpeace incineration report. It concludes, "With the limited data available, it is, therefore, impossible to predict health effects of incinerators, either new or updated installations… There is an urgent need for the complete phase out of incineration and the implementation of sound waste management policies based on waste prevention, re-use and recycling." (Allsopp et al 2001)

 

6.2.3            Judgements about risk

Disagreement about the management of a potentially risky activity like incineration arises not only because of different interpretations of scientific evidence but because of the different judgements people make about how risky they believe the activity to be. Individuals as well as regulatory bodies try to avoid or control activities they judge to be too risky and ignore or tolerate others. Conflict occurs when people form different judgements about the riskiness of the activity. Disagreements about risk are inevitable because there is no way to define risk that does not include values, beliefs and assumptions – especially when information on which to base the judgement is scarce.

Where there is uncertainty, judgements about risk are based on assumptions and mental strategies that help decision making and on qualitative aspects inherent in a hazard. As well as the likelihood of harm, people consider whether incurring the risk is voluntary, has catastrophic consequences, is unknown and unfamiliar, and is new to society. Judgements about risk are also influenced by individuals' views of the world and the kind of society they want. A summary of current thinking about risk perception can be found in Saffron (1993).

When scientists make judgements about risk, the process is described as risk assessment. Risk assessment is perceived as an objective exercise and is expressed in terms of probabilities – the likelihood that something bad will happen. If the probability is low, then they perceive the risk to be low; a high probability describes a high risk. This one-dimensional view of risk enables scientists to consider the risks of eating 40 tablespoons of peanut butter in a year, drinking 30 cans of diet soda in a year and cycling ten miles in a year as equivalent because each increases an individual's chance of death by one in a million. The assumptions, values and lack of actual data in risk assessment are rarely made explicit, contributing to an impression of scientific validity. An example of a fact-free, assumption-implicit risk assessment is given by Hens (Hens 2000) for an organic chemical that accumulates in the body. The risk assessment takes account of the maximal concentration of the chemical in the plume using a terrain dispersion model to estimate ground level concentrations. A theoretical amount of the chemical which an adult might expect to assimilate is then calculated. The assumptions hidden in this kind of risk assessment are that the hypothetical adult is free from any pollutant in their body and will not be exposed to chemicals or other hazards from other sources. This type of risk assessment is unlikely to lead to emission standards or acceptable daily intakes that would protect human health. Hens likens risk assessment to a "captured spy – if you torture it enough, it will tell you anything you want to know."

When members of the public make judgements about risk, the process is described as risk perception. Opposition to an incinerator, for example, may be condemned as irrational and ignorant but in fact, scientists make use of the same mental strategies, known as heuristics, as the non-scientifically trained public. The commonly used heuristics are:

•   Availability – overestimate frequency of rare, unusual, memorable causes of death (e.g. accidents) and underestimate more common ones (e.g. diseases).

•   Overconfidence – unwarranted certainty in the correctness of their estimates.

•   Trustworthiness of public institutions and officials – recognition that human errors, organisational failings and patterns of management can affect real life operation of technological systems.

•        Framing effect – attitudes to risk influenced by the way choices are presented, e.g. a half empty glass seems worse than one that is half full.

•   Optimistic bias – impression that the individual is less vulnerable and more knowledgeable about a hazard than other people.

•        Dose response – belief that chemicals are either safe or dangerous.

 

When there is little knowledge and much uncertainty, experts are as prone to the use of these heuristics as the public. Scientists may underestimate risks of technologies they are familiar with, may suffer from overconfidence in their judgements and may be insensitive to wrong assumptions in their work. They are often under political or economic pressures which can bias their judgements.

There are other aspects of risk that affect how risky individuals judge the activity to be and how much dread or distress is associated with it. These so-called outrage factors can be measured, assessed and controlled in the same way that hazard can be. Outrage covers qualitative aspects such as:

 

Given the diversity of groups and views in society, there will never be consensus on risks or how to manage them. Better management of risks is possible if the different approaches to risk are recognised as valid. The main lessons for education and communication are making value judgements explicit, acknowledging and validating the outrage factors and communicating truthfully. For public decision making, the lessons are about sharing power and responsibility and about fostering public trust.

6.2.4            Precautionary principle

One way to manage the risks associated with waste management is to apply the precautionary principle, which is defined in The Rio Declaration on Environment and Development (UNCED 1992) as follows:

“Where there are threats of serious or irreversible damage, lack of full scientific certainty shall not be used as a reason for postponing cost-effective measures to prevent environmental degradation. When in doubt about the impact of a development, it will be managed according to the worst-case scenario of its impact on the environment and human health.”

The conditions under which the precautionary principle applies are:

•        When health effects are most serious or irreversible.

•        When the subject is a matter of scientific uncertainty and full evidence is lacking.

•        When cost-effective measures are possible.

All three conditions apply to waste management (Hens et al 2000). Hens argues that to protect health, adherence to the waste hierarchy is necessary (see Figure 2). Although this is universally accepted as a good idea in Britain and throughout the EU, the majority of waste is sent to landfill, the option of last resort in the waste hierarchy. To move away from landfill and towards waste minimisation and re-use, the precautionary principle should be applied in all waste management decisions. Cost-effective measures to make waste prevention effective are environmental taxes, health impact assessment, and environmental education.

6.3    The role of public health agencies

What role could or should public health agencies and professionals play in waste management policy making and planning?

6.3.1            Questions the public want answered

Standard health risk assessment methods tend not to address the public’s ways of judging risk. An analysis of 20 environmental reviews of waste management decisions in the United States (Konheim 1991) revealed the most common questions the public want answered (see Box 2 below).

The ideal approach is to carry out a health impact assessment that includes an evaluation of alternative risks and courses of action, the potential for catastrophic incidents and ways for people affected to control the risks in a meaningful way.

6.3.2   IPPC applications

Since new regulations came out in 2000, health authorities (now devolved to primary care trusts) are statutory consultees in the IPPC (Integrated Pollution Prevention Control) application process and have been asked to comment on the health impacts of plans to permit new waste disposal processes. It is not yet clear where this responsibility will rest with the abolition of health authorities; CCDCs (consultants in communicable disease control) may be asked to lead, but are not usually trained in environmental epidemiology and may not feel prepared to comment.

CIRS, the Chemical Incident Response Service, is preparing a toolkit for use by CCDCs when they are consulted about an IPPC application. The toolkit is in the form of a database plus navigation document. It provides a series of questions CCDCs can use to check whether the applicant has taken health impacts into account in their application. The questions cover site characterisation, monitoring systems, the method used by the applicant to determine the impact on the local population, modelling data, chemicals on site, emissions to the atmosphere, presence of action plans, and the possibilities of noise and odour pollution as well as completeness of the application and information about the type of permit. The toolkit is in the pilot stage and should be available by the end of 2002. For more information, contact Graham Robertson, CIRS, email

The official Department of Health IPPC contact is Professor Rod Griffiths, Regional Director of Public Health for the West Midlands Region. A checklist guidance document for CCDCs has been produced on how to respond to IPPC applications that come their way (Kibble 2001).

6.3.3   Local authority waste strategies and waste local plans

Local authorities carry out extensive consultation exercises in the formation of their plans. The consultation process is laid down by statute and the views of interested parties are sought. Comments from health authorities are welcomed but there is no statutory obligation to seek out the views of public health professionals. Nor is there a statutory requirement to carry out a formal health impact assessment when preparing waste local plans and structure plans. The plans set out general policies and principles which guide policy making. To assess best practicable environmental option, key criteria are listed including an environmental statement and life cycle analysis. Under Environmental constraints and issues, policies are laid out for nature conservation, landscape, archaeology and the historic environment, agriculture, and water. Health is not specifically mentioned. It is assumed that health impacts are adequately covered in the existing environmental impact assessment. Given the uncertainties in the epidemiological data, it may be the case that the current risk assessment methods based on emission standards are as accurate as can be achieved.

6.3.4            Regional waste strategy

The Regional Assembly for the South West has begun the process of producing a regional waste strategy and welcomes public health input (Joe Field and Brian Cook, personal communication).

6.3.5            Health impact assessment

The White Paper Saving Lives, Our Healthier Nation states that there is a need for health impact assessment of policies, plans and projects at national, local and regional level. The Government has made a commitment to consider health in all aspects of policy making, not just in relation to the health services but to any policy which affects people’s well being and quality of life. The Department of Health has explained HIA as:

A prospective assessment of a proposed new policy to identify its likely impacts on health. This aims to provide assessment of policy options and their differing potential health benefits and disbenefits in order to maximise health outcomes;

or

A retrospective assessment or evaluation of a policy following implementation. This aims to monitor how a policy is affecting or has affected health. The results of such a process can then be used to fine tune the future direction of policy implementation. (Department of Health 1999)

The Welsh Assembly has produced guidelines on choosing formats for HIA (The National Assembly for Wales 1999, p28).  They stress that the HIA methods which are appropriate for assessing projects are likely to be different from methods for assessing a policy. When choosing a method, decision makers should be guided by the need to make it add value to the decision making process.  A HIA must do more than point out that a new development may create noise and air pollution. Methods should be chosen which provide information on the size and nature of the health impact while, at the same time, not ignoring those impacts which are impossible to quantify.

Although there is no standard methodology for carrying out an HIA, there is considerable experience with the process in other countries and within the UK. The following procedures are from the Merseyside Guidelines:

1. Screening – procedure whereby policies are selected for assessment. The idea is to see if the project or policy is likely to have significant impacts on health and if it is worth subjecting it to a HIA. A checklist from the British Columbia Health Impact Assessment Toolkit can be found in Developing Health Impact Assessment in Wales (The National Assembly for Wales 1999 p19).

2. Scoping – a multidisciplinary steering group is established to agree the Terms of Reference. Steering group should include commissioners of HIA, assessors, policy proponents, affected communities and other stakeholders.

3. Conducting the risk assessment – characterising the nature and magnitude of the harmful and beneficial factors, how many and which people will be affected by them and how they will be affected.

A.             Policy analysis

B.             Profiling of affected communities

C.             Interview stakeholders and key informants

D.             Identify health determinants

E.             Collect evidence from other reports and assess evidence

F.             Establish priority impacts

G.             Recommend and justify options for action

4. Appraise the assessment

5. Decision making

6. Monitoring and evaluation

The use of an integrated environmental and health impact assessment is described by Fehr (Fehr 1999) for the planned extension of a non-toxic waste disposal site in Lower Saxony.  A ten-step environmental health impact assessment model was applied and its use assessed. Fehr argues that such an assessment should be used more often as a tool for health protection and promotion but that a consensus is needed on the concept and further development of the tool.

A HIA is an iterative and an interactive process, based on principles of participation, equity, democracy, and a broad definition of health. The aim is to incorporate a public health perspective into the waste planning process. This requires intersectoral collaboration. If policy makers from local authorities were involved from the beginning of the HIA process, they would have a sense of ownership and interest in the process which would make them more likely to consider health impacts when they prepare their Waste Local Plans and Waste Strategies. If public health officials were involved in the waste planning process from its beginning, they would have more impact than if they were commenting on an already prepared and accepted plan.