The review was recommended by the Government's Strategy Unit in 2002 in order to help planners and councils make decisions about waste facilities, and to make the public more accepting of such facilities - particularly incinerators.
The review was due to appear alongside last November's pre-Budget report but publication was delayed after the Royal Society concluded that the review had "significant limitations that restrict its usefulness to those making policy decisions," and that caveats associated with the uncertainties were not presented adequately.
The final report was published by DEFRA in early May - almost a year after the Strategy Unit's suggested deadline. Although the report acknowledges the uncertainties, said the Royal Society, "it is important that anyone using these data takes adequate consideration of its inherent uncertainty."
The report came under strong criticism from environmental groups. Its key weakness is that despite being billed as a review of "environmental and health effects", the environmental element is limited to air emissions - failing to review studies which have compared the relative environmental performance of different waste treatment technologies through life-cycle assessment (LCA).
Friends of the Earth was quick to point out that the study did not include an analysis of the greenhouse gas emissions associated with recycling compared with landfill and incineration.
Independent LCAs tend to conclude that recycling is usually environmentally preferable to incineration from the point of view of resource consumption and greenhouse gas emissions. The most recent example is a European Environment Agency review of nine LCAs comparing the recycling and incineration of paper.2 A major LCA research programme by the US Environmental Protection Agency in the 1990s concluded that municipal energy-from-waste incineration and landfill were level pegging with respect to net emissions of greenhouse gases - while most forms of municipal waste recycling were streets ahead (ENDS Report 270, pp 12-14 ). Similar results were obtained in a study for the European Commission in 1997 (ENDS Report 267, pp 23-26 ).
The Royal Society said that this lack of a life-cycle approach in DEFRA's new report was a "major limitation", and that its absence was a surprise given that the Government's own waste strategy recognises LCA's importance. "Had the terms of reference, which were established before our involvement in the project, taken a life-cycle approach, this report would have produced different results and allowed a better comparison of the options."
Consequently, the report should be used in conjunction with tools that adopt a life-cycle approach, said the Royal Society, such as the Environment Agency's WISARD software package (ENDS Report 299, p 18 ).
The report also suffers from a lack of data on releases from facilities to soil and water, and on technologies such as mechanical/biological treatment, anaerobic digestion, pyrolysis, gasification and composting.
Comparing waste facilities with economic activity as a whole, the review found that for most pollutants, waste facilities account for less than 2.5% of total air emissions for which data are available. The two exceptions are methane from landfill sites, which accounts for 27% of national methane emissions, and cadmium, which represents 10% of total emissions.
The review found no evidence of a link between living near to landfill sites and the cancer incidence but it acknowledged that one study identified a possible link with some birth defects - without establishing a causal link (ENDS Report 319, pp 13-14 ).
The review found no evidence for a link between the incidence of cancers, respiratory diseases or birth defects and the current generation of municipal incinerators.
In his foreword to the report, DEFRA's chief scientific advisor, Professor Howard Dalton, said he had "confidence in this conclusion". But he added that "rigorous enforcement will be crucial" to ensure that non-standard operating conditions - which were not included in the review's scope - do not lead to emission levels that would "give rise to concern".
The report finds that emissions from incinerators "could have an effect on local air quality". For example, mercury emissions from incinerators contribute 20% of the overall background mercury concentration at nearby locations.
Incinerators were also found to produce the greatest emissions of nitrogen oxides, and to be an important source of particulates, both of which contribute to poor air quality. NOx also contributes to acid rain and eutrophication.
The National Society for Clean Air said the report's emphasis on air emissions would do little to help councils assess "the wider life-cycle benefits of recycling, composting and other treatment technologies". But it hoped that it would "put an end to scaremongering over the health impacts of facilities like incineration."
The report also includes an attempt to quantify the health effects of the main types of waste facilities, although it accepts that a range of factors make its work "less than ideal". Very few conclusions can be drawn from this analysis, although in general terms anaerobic digestion compares favourably and incineration poorly. A similar attempt to compare the environmental effects broadly reflects the waste hierarchy, with landfill and incineration having the greatest number of significant impacts.
Urging councils to "press ahead urgently" with the task of approving planning applications for new facilities, Environment Minister Elliot Morley said the report "shows that risks to human health from incineration are small in comparison with other known risks." Incineration must be "acknowledged as a sustainable waste management option" - albeit one that falls below recycling and is suitable for "dealing with the residual waste that will still be left even after...recycling and reuse."
The study said that no link has been found between composting facilities and the occurrence of cancers and asthma, but that a recent study showed that there might be a link between emissions from a particular composting facility and the incidence of bronchitis in nearby residents. Open-air composting also produced the highest emissions of particulates, although the data were of poor quality and emissions from new "in-vessel" facilities will be much lower.
The waste industry will hope that the report will lessen opposition to new waste facilities. The Environmental Services Association said that "contrary to long-standing myths" the "comprehensive" report proves that waste facilities present "minimal risk to health". This message could well sway some councillors and council officers - but the likelihood of opponents being won over is more remote.
The Green Alliance was "disappointed" that the report did not result in a clear statement of the Government's preferred waste management options and how economic instruments - such as an incineration tax - could be developed to drive them forward.
However, a second report examining the costs and benefits associated with the health and environmental impacts identified in the study is due to be published shortly.