Health Impact Assessment for Sustainable Water Management
Health impact assessment (HIA), in theory, ‘does exactly what it says on the tin’ – that is assesses impacts on health. The techniques can be applied to virtually anything – policies, programmes or projects. The idea, in a nutshell, is that HIA aims to predict health issues before any policy, programme or project is implemented and hence influence the decision-making process, with the hope that negative impacts can be mitigated and positive impacts enhanced. Investing in HIA is justified by four compelling points, namely; economics, equity, best public health practice and good governance, all of which are required for policy implementation based on principles of sustainable development.
Content Table
Definitions
The definition of health adopted greatly affects the subsequent HIA and there are two broad paradigms:
- the reductionist ‘biomedical’ approach, where health is considered within a series of disease categories (e.g. communicable disease, non-communicable disease, nutrition, injury, mental disorder and so on) and the health sector structure and operations deal with these through the delivery of health service; and
- the ‘social or public health model’ where health is considered to be a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.
A range of interwoven factors (determinants) are acknowledged to play a role in community health and it is these determinants (such as social and economic factors, environment, lifestyle and behaviour) that are affected by development decisions. HIA aims to predict the changes to these determinants.
The HIA Process
The HIA process basically consists of a set of procedures, or series of steps, that need to be systematically applied, these include:
Screening
A desk-based preliminary exercise applied to a proposed project, programme or policy, to decide whether investing in a full-scale HIA is warranted.
Scoping
A process setting the temporal and spatial boundaries for the HIA, identifying the range and types of potential negative and positive health effects considering specific phases of the project and identifying vulnerable population groups. The output of the scoping process can be utilized as a basis for a formal set of terms of reference for the full-scale HIA.
Assessment
The actual hazard identification, risk assessment and impact synthesis process, followed by the formulation of conclusions and recommendations for safeguards, mitigating measures, public health management plan and health promotion.
Appraisal
The quality component of HIA, focusing on the objectivity, comprehensiveness and evidence-base of HIA and on technical soundness and economic feasibility of propped measures.
There is no single ‘correct’ way to perform the assessment step and HIAs may vary in depth and complexity, from a desk-based approach, which provides a broad overview of possible health impacts and relies on the collection and analysis of existing and readily accessible data to in-depth examinations, which provide a comprehensive assessment of potential health impacts and will involve on-site visit, interviewing key stakeholders, and collecting and analysing relevant health data using a diversity of methods and sources. The approaches to the assessment step also vary and may be qualitative or largely quantitative in nature.
HIA of water-based projects and programmes
Without HIA of water-based projects and programmes there is a real risk of damaging the health of local populations. In the past, when development was generally undertaken without even an informal assessment of possible health impacts, unintended negative health effects have included such diverse impacts as the spread and intensification of vector-borne disease transmission, particularly schistosomiasis and malaria, associated with hydropower projects and irrigation schemes, intensification of dengue transmission following the introduction of storage jars for drinking-water in Viet Nam, arsenic poisoning as a result of using contaminated boreholes for drinking-water supplies in Bangladesh and mental health impacts resulting from forced settlement out of reservoir areas or irrigation schemes.
In many countries, the pressure on water resources is intensifying, with water scarcity already affecting every continent and four out of every ten people in the world. Population growth and urbanization, and possibly climate change, will exacerbate this problem. Thus, there is a need to develop new resources, decrease demand, enhance efficient water use and implement recycling or reuse measures. With increasing demands for ‘sustainable development’ and the acknowledgement that the greatest scope for improving public health lies outside the traditional medical profession (which focuses on management of illness), HIA has become an important instrument to manage and mitigate possible health implications in advance of any development.
The enthusiasm with which HIA has been adopted varies. The UK is a leading nation, certainly in terms of published reports in the peer-reviewed international literature, with investigations covering topics as diverse as an HIA of the National Botanic Garden of Wales to considering regional transport strategies. Although HIA is most common in industrialized nations, a number of developing countries have also implemented HIA. Examples include assessments of water resource management policy in Thailand and reservoir construction in Lao PDR, although in many instances the HIA reports are not in the public domain, and hence difficult to obtain.
HIA, in theory, ‘does exactly what it says on the tin’. The ‘in theory’ relates to the fact that we need to deepen our knowledge and that HIAs can be performed in a multitude of different ways. Often, for example, baseline health data (especially in developing countries) are missing and where desk-based studies are being conducted there is little or no opportunity to gather new data, meaning that the best must be made of what is available. Despite this, HIA provides the opportunity to improve population health and in the words of, former WHO Director-General, Dr Halfdan Mahler “I know that health is not everything, but without health, everything else is nothing”.
Rainwater harvesting in the UK – Hazard identification
A desk-based HIA of in-house rainwater harvesting was conducted on a hypothetical population, of almost 5000 people, living in a newly built estate in the South of England. Each property was assumed to have an in-house rainwater harvesting system, with an underground tank, collecting rainwater from the roof via downpipes, passing through a filter on entry to the tank. The tank receives top up supplies from the mains water when it is running low and the supplies are used for toilet flushing and garden watering.
In broad terms, the following hazards were identified and explored in greater detail:
· Drowning and near-drowning;
· Injury; and
· Infection.
Infection relating to rainwater harvesting could occur via a number of routes, namely:
· Inappropriate ingestion/contact: through ingestion of aerosols produced as a result of toilet flushing; direct ingestion via the garden tap; direct contact through using the garden tap to fill up paddling pools, hot tubs and so on; inadvertent ingestion/contact through contamination of drinking-water supplies as a result of cross connections.
· Inhalation of microorganisms within an aerosol.
· Microbial contamination of the environment and subsequent ingestion of garden produce contaminated as a result of watering with stored rainwater.
· Vector-borne illness.
The overall health impact statement was divided into a quantitative score (burden, expressed as disability-adjusted life years) and a qualitative component. The greatest risk associated with introducing the system derived from injury as a result of using a ladder to clean guttering.
Nam Theun hydroelectric project
An HIA of the Nam Theun 2 project in Lao PDR (Krieger et al., 2008) was conducted by considering eleven environmental health areas (respiratory diseases; vector-related illnesses; sexually transmitted infections; soil- and water-borne diseases; food and nutrition; accidents and injuries; exposure to potentially hazardous materials; psychosocial impacts; cultural health practices; health service infrastructure and capacity; and programme management delivery systems), five different population groups (based on age and gender), ten potential impact areas of concern (including resettlement areas [for the approximately 6000 people] and construction work camps, for the approximately 400 workers) at three different project time points (construction, reservoir filling and operation). A field-visit to different project sites, discussion with different stakeholders (e.g. project staff, local villagers, health personnel and international organizations) and data gathering (mainly qualitative) and analysis of existing baseline health and economic data enabled the team to identify groups most at risk of specific negative health impacts and suggest mitigation strategies to minimise these effects. The HIA ultimately assisted in the drafting of the public health management plan.
Related Articles
- Drinking Water Standards
- Health Impact Assessment
- Wastewater Indicators
- Waterborne Dieseases
- A Brief History of Water and Health from Ancient Civilizations to Modern Times
References
The issues in this article are addressed in the book, Health Impact Assessment for Sustainable Water Management, edited by Lorna Fewtrell and David Kay. To order the book, CLICK HERE.
