By announcing the construction of an incinerator to solve Rome's waste problems, Mayor Roberto Gualtieri reopened the debate on the use of these plants, also called waste-to-energy plants to emphasize that they produce energy by burning garbage. Reflections on the topic must take into account various aspects, including the size of an incinerator, how it integrates into the wider waste disposal and recycling system, and its environmental impact in terms of greenhouse gas emissions, those that cause climate change.
For many people, however, the most worrying aspect of incinerators is their health, as in the past their use caused the production of heavy metals, dioxins and other substances which have been linked to an increased risk of developing some forms of cancer (stomach, colon, liver and lungs). The more recent plants, however, are different from those of the twentieth century and must comply with much stricter standards on the diffusion of pollutants: thanks to these improvements, things have changed a lot.
In addition to carbon dioxide, which is the main greenhouse gas but has no direct negative effects on health, the activity of incinerators produces a series of pollutants, some common to all combustion processes, others specific to that of waste. The first category includes particulate matter, the set of solid and liquid substances that remain suspended in the air in particles with a diameter of up to half a millimeter, and which are also produced by industries, gas heating systems and road traffic: their presence in the atmosphere can induce problems in the respiratory and circulatory systems. Then there are sulfur dioxide (SO2), nitrogen oxides and carbon monoxide (CO): substances that are toxic or considered carcinogenic.
Polycyclic aromatic hydrocarbons (PAHs), which belong to the second category, are also carcinogenic, together with for example some heavy metals such as cadmium and mercury and dioxins.
Over the years, the regulations on the emissions of these substances have been updated several times, both at European and Italian level, and both industries and incinerators must comply with stringent limits for each of them, using filtering systems. The limits are set in the so-called BREFs, a series of reference documents linked to the European directive on pollution prevention and reduction that list the “best available techniques” (BAT), ie the best technological methods available to contain emissions. And as regards waste incineration, the limits are more restrictive than in all other industrial sectors.
In the last twenty years, the amount of waste incinerated has increased, from 2.2 million tons in 2000 to 6.3 million tons in 2018, according to data from the Higher Institute for Environmental Protection and Research (ISPRA). but thanks to these limits and to the technologies they impose their use, the contribution of municipal waste incinerators to the emissions of some pollutants has decreased, even in absolute terms: this is the case of sulfur dioxide, cadmium, PAHs and dioxins (among the most dangerous substances). To give an example: in 2000, Italian incinerators emitted 65.5 kilos of polycyclic aromatic hydrocarbons, equal to 0.1 per cent of the emissions of these substances in the country; in 2018 only 3.3 kilos, corresponding to 0.004 per cent of the total.
Even for substances for which emissions from incinerators have increased as an absolute quantity over time, the percentage contribution is very low – the largest one concerns lead and is equal to 1 per cent: gas heating systems contribute enormously more. to the diffusion of particulates and carbon monoxide, transport is the main culprit for nitrogen oxides and the industrial sector for dioxins.
A summary of what we know about the relationships between the activity of the most modern incinerators and the health of the people who live around them is contained in the White Paper on the incineration of municipal waste published in 2020. It is a report commissioned by Utilitalia, the federation of Italian companies that supply water, electricity, gas and waste disposal, but made by researchers from various universities. The part dedicated to health was handled by the doctor Andrea Magrini and by the engineer Francesco Lombardi, professors at the Tor Vergata University of Rome, and summarizes the knowledge on the subject based on 12 studies carried out in Italy and abroad over the last 20 years. In summary their analysis says that:
On the basis of the available studies, in general, a well-designed and properly managed incineration plant, especially if of recent conception (from the 2000s onwards) emits relatively modest quantities of pollutants and contributes little to environmental concentrations and, therefore, there is no evidence that it involves a real and substantial risk to health.
Among the studies taken into consideration by Magrini and Lombardi there is a series of epidemiological investigations financed by the Emilia-Romagna Region (together with Lombardy the one in which there are more incinerators), carried out between 2007 and 2012 to study the relationships between the exposure to pollutants emitted by municipal waste incinerators and some medical conditions among the population, in particular linked to pregnancy and cancer. Studies did not find an association between incinerators and sex ratio at birth, twin births and infant weight at birth, while they suggested an association with miscarriage and preterm birth rates. However, it must be borne in mind that this association was detected for pregnancies that occurred between 2002 and 2006: since then all the incinerators taken into consideration have been renewed, updating the filtering technologies.
As for tumors, “the study did not highlight a consistent association between levels of exposure and mortality or incidence of tumors”, despite having found some clues on the possible carcinogenicity of the emissions. And in turn it has actually analyzed the possible effects of incinerators that have subsequently been modernized.
Another more recent study, from 2018 and cited in the White Paper, concerns the incinerator of Valmadrera, in the province of Lecco. The purpose of the study was to verify the possible relationships between the residence in the areas close to the plant (renovated between 2006 and 2008) and the incidence of some medical problems, including tumors: no particular frequency of the types was found. diseases generally associated with emissions of substances such as those produced by incinerators (non-Hodgkin's lymphomas, soft tissue sarcomas, cardiovascular and respiratory diseases). A higher incidence of liver and biliary tract cancers was found among people residing in the area closest to the incinerator, but since these are not diseases generally associated with incinerator pollution, the researchers declared the need for further investigations to establish the causes. On the other hand, there was no particular incidence of health problems among newborns.
In conclusion, the incinerators that comply with the BREFs – and therefore even more so for the more recent ones or those still to be built – are not considered risk factors for cancer or negative effects on reproduction according to the scientific studies available. However, epidemiological monitoring in the sector continues: an example in this sense concerns the Turin incinerator, started only in 2014, for which there is a health surveillance program that began with the ignition and continues to this day. The next results will be released in 2023.
