Studies confirm higher rates of birth defects and increased cases of child and adult cancers around municipal waste incinerators. Emissions often comprise a major source of fine particulate matter, toxic metals, in excess of 200 organic chemicals, and hormone disruptors. This article therefore examines the resulting price potentially paid by the public for the disposal of municipal, industrial, radioactive, clinical and domestic wastes, with ‘price’ being an acronym for Pollution, Respiration, Incineration, Contamination, & Emissions.
The 8th Century Indian Hindu scholar and philosopher Adi Shankara once stated 'Life is fragile like a raindrop on a lotus leaf’, and to quote the 20th Century American poet and philosopher Anthony Liccione, ‘Life is like a lit cigarette. The past is ashes, the present is burning, and the future is up in smoke.’ A cigarette can therefore be considered as a miniature incinerator smokestack since it comprises organic matter, not unlike the bulk of waste that reaches a municipal incinerator, whilst producing similar particulates and poly-aromatic hydrocarbon compounds (PAHs) when burnt.
Continuing with the theme of life, an energy from waste plant operating in south-east England over the past 5 years has resulted in reduced recycling rates whilst at the same time heralded a sharp increase in infant mortality rates. Burning waste now produces the same amount of greenhouse gases for each unit of energy as coal power and a £1 billion 25 year waste incineration contract for this plant has already yielded numerous breaches of its Environment Agency licence-to-operate without any meaningful sanctions to protect public health. So much for effective environmental policing!
The number and volume of different types of wastes produced in the UK, together with their potential toxicity are ever increasing and the use of incineration is growing given that it is seen as a solution to these troublesome problems. However, the process of incineration in itself creates pollution by discharging hundreds of toxic and bio-accumulative pollutants into the atmosphere, coupled with their ability to create waste ashes that can cause chronic ailments via various mechanisms of environmental exposure. Uncontrolled incinerators, including those treating solid and hospital wastes, are often the worst culprits of environmental release due to incomplete burning. But technology is available that allows for controlled waste incineration.
Municipal waste incinerators deal with a great variety of waste materials and the composition of incinerator emissions will therefore vary with the types of waste being burnt at any given time, together with the efficiency of the incineration facility being employed and the effectiveness of any control measures put in place. This diversity of incinerator feedstock and hence incinerator emissions, coupled with a lack of standardisation of studies on related health effects, make firm conclusions regarding associated health risks particularly difficult. Of particular concern are those incinerators required to assist in the disposal of radioactive wastes. Incineration does not reduce radioactivity of such waste and whilst mandated smoke filters remove large particles from the air, small easily ingested or inhaled particles are released. Any subsequent inhalation of radioactive particulate matter results in ingested materials emitting highly destructive alpha and beta radiation within the body itself.
Most modern incineration equipment is automated but requires ongoing calibration and maintenance coupled with continuous sampling and analysis of the waste streams. For hazardous-waste incinerators, environmental regulations require extensive monitoring of key incineration process conditions, including combustion temperatures; gas residence time; air pollution control-system operating measures; and stack-gas concentrations. Notwithstanding these measures, many emitted compounds are known to be toxic but are also bioaccumulative and persistent in the atmosphere where they can disrupt hormone regulation, trigger cancer, attach to chromosomes, affect the immune system, and even alter behaviour and lower intelligence.
Tiny particles in the air, otherwise known as particulates, are produced in huge quantities by incinerators. These are heterogeneous clumps of incompletely burnt waste in solid or aerosol form, classified by size rather than composition and so do not uniformly share a predictable chemical property as this varies according to what has been burnt to produce the particulate. The constituents of particulates include nitrates, sulphates, a number of organic compounds including PAHs, biological compounds such as bacterial toxins from rancid organic waste and fragments of animal or bacterial cells, and a number of including iron, copper, nickel, zinc, manganese and vanadium.
Particulates cause problems in humans by virtue of their small size. Such particles irritate the airways and cause chronic inflammation that in itself gives rise to conditions in which the lung structure is degraded resulting in emphysema or becomes permanently inflamed thus causing chronic bronchitis. In practice, both emphysema and chronic bronchitis to some extent occur together giving rise to the umbrella term chronic obstructive pulmonary disease (COPD). Very fine particulates, especially those with a diameter of less than 2.5 microns, designated PM2.5, are known to cause an increased risk of lung cancer and of cardiovascular disease. These particles are small enough to lodge in the lining of arteries, known as the endothelium, where they set up an inflammatory response which damages these blood vessels and promotes the formation of fatty deposits, the atheroma, that fur up arteries. Depending on where atheroma develop, they can lead to angina, heart-attacks, strokes, foot ulcers, gangrene, dementia and impotence. Interestingly, the risks posed to health are determined by the number and size of particles and not by the weight of contaminants ingested.
According to the World Health Organisation, cardiovascular disease is the leading cause of death worldwide and COPD is not far behind in fourth place. The vast majority of cases of COPD, lung cancer and a large proportion of cardiovascular disease are caused by smoking and not by living in proximity to an incinerator. However, it is increasingly the case that atmospheric pollution, attributable in part to municipal incinerators, is recognised as an independent risk-factor for these illnesses. It is worthy of note that independent risk-factors are personal variables that increase the likelihood of developing a particular illness. For example diabetes, smoking and hypercholesterolemia, otherwise known as high cholesterol, are independent risk-factors for cardiovascular disease whilst smoking, heavy metals, and asbestos exposure are risk-factors for lung cancer.
An investigative analysis conducted over 10 years ago also examined miscarriages occurring in women between the ages of 15 and 49 years who lived close to 7 incinerators in northern Italy. The study determined that increased particulate emissions from these incinerators, located within a region whose capital is the city of Bologna, were directly associated with an increased risk of miscarriage.
Incineration waste particulate matter includes an inorganic ash fraction that consists of mineral matter and metallic species, and a carbonaceous soot fraction which is a product of incomplete combustion comprising unburned carbon in the form of fine particles or deposits on inorganic matter. Studies have shown evidence of higher rates of adult and childhood cancer around municipal waste incinerators and human susceptibility to chemical pollutants is greatest at the foetus stage of development.
Public Health England has advised that there is no proven increased risk of infant mortality from exposure to municipal waste incinerator emissions, based on studies from the Small Area
Health Statistics Unit at Imperial College, London. However, it did find that for babies born within 10 kilometres of these plants there is a small increased risk of ventricular septal defects that may comprise a hole in the wall that separates the heart’s lower chambers and congenital abnormalities affecting the structure of the heart. Furthermore, cancer rates have been found to correlate geographically with toxic waste treatment facilities and with increased exposure to chemical industry infrastructure. The incidence of lung, bowel, stomach, and gallbladder cancers, together with soft-tissue malignant tumours and blood cancer affecting the immune system have all been shown to correlate with proximity to a municipal incinerator. Consequently, the health impacts associated with incineration include significant ill health and death.
Development of cancers is dependent on many factors and requires either genetic abnormalities that predispose to their development, or cumulative causes of injury over many years to specific portions of deoxyribonucleic acid (DNA). A lot of DNA can be damaged and produce little in the way of ill effect, but injury to genes involved in cell and tissue growth, or tumour suppression can give rise to cancer if there are multiple causes of such injury over years. This is why cancers are common in the elderly and rare in children. DNA may also be disrupted by exposure to some chemicals.
One of the major classes of pollutant formed from incomplete combustion are PAHs which are hydrocarbon compounds containing more than one benzene ring. Hundreds of these compounds have been identified and lots of different ones are produced according to the waste being incinerated. In addition, a great number of similar aromatic compounds are produced containing atoms other than hydrogen and carbon but which carry the same health risks. The toxicity of these chemicals is hugely variable; around thirty thousand-fold from the most innocuous to the most toxic. PAHs can cause genetic changes in adults, children and the unborn foetus, thereby creating severe health risks to current and future generations.
Fine particulate matter created in incinerators is able to adsorb organic toxins and toxic metals and then carry these into the bloodstream where they can accumulate in the body. Air pollution has been demonstrated in studies in the United States to affect neuro-development in children, very possibly giving rise to various behavioural and emotional problems, including learning difficulties, dyslexia, delinquency, attention deficit & hyperactivity disorder (ADHD), and autism, though race and socio-economic status are confounding factors here too. Also there are various mechanisms of injury caused to nervous tissue termed neurotoxicity. In adults, this same neurotoxic contamination can give rise to depression, Parkinson’s disease, dementia and violent behaviour.
As incinerator feedstocks vary according to locality and the time of year, the reactions taking place in the heat produces very varied emissions. These are likely to contain unidentified compounds whose potential for causing harm is as yet unknown. This was once the case for dioxins which were only isolated for the first time in the mid-1980s, and as the nature of waste is continually changing together with the chemical nature of emissions, their potential for adverse effects upon health is also changing. These risks are further compounded by the fact that two of the most hazardous emissions, namely heavy metals and fine particulates, are relatively resistant to any removal processes.
Toxic metals are universally present in incinerator emissions and are of high concentrations within fly ash. After compaction the bottom and fly ash produced account for between 30% and 50% by volume of the original waste. This ash is then disposed of in landfill. Fly ash is light in weight and the dioxins and heavy metals contained within it can therefore become readily airborne thereby creating further health hazards such as crop contamination and the resulting impact on food production and supply. As dioxins are highly stable they are able to persist in the food chain, gradually accumulating in the larger animals, ultimately including humans, that ingest them.
There are many variations to the process of incineration but a typical facility comprises a number of distinct stages: storage of waste; preparation of feed stock; furnace combustion; residual bottom ash removal/disposal; hot gas release; heat recovery via steam generation; gas cooling; removal of pollutants; disposal of residuals; and treated gas dispersion to atmosphere. The design features, combustion operating parameters and air-pollution control processes commonly used in municipal, hazardous and medical waste incinerators have the greatest influence on emission types, but emission rates during normal operation can be disturbed by start-up and shutdown events. While incineration plants are operating normally, the potential for operator exposure to hazardous materials is greatest and without appropriate controls and protective equipment personnel can be exposed to hazardous dust and vapours. Moreover, the combustion process provides the highest potential source of fugitive dust and vapour emissions coupled with the greatest potential for fire hazard.
Incineration comprises a rapid exothermic reaction between fuel-waste and oxygen sourced from air. In a well-designed incinerator the flame zone is sufficiently hot to break down all organic and many inorganic molecules thus permitting reactions between the majority of volatile components within the waste-stream together with the oxygen and nitrogen within atmospheric air. Incinerators emit a wide range of organic pollutants including PAHs, polychlorinated biphenyls (PCBs) ketones, aldehydes, phthalates, alkenes, furans, dioxins, and organic acids.
Activated carbon comprising finely divided particles has a large surface-area-to-volume ratio and is used to great effect in adsorbing a wide range of vapour-phase compounds. The powdered carbon is injected into flue gas streams and the carbon particles adsorb onto their surface a number of hard to control vapours including those of mercury, dioxins and furans before the particles themselves are captured by air pollution control devices prior to disposal.
Carbon dioxide and water vapour comprise the principal emissions from the combustion process but gas cooling techniques are integral to incineration system design and are often important with respect to other pollutant emissions since the rate of gas cooling can affect emissions of mercury, dioxins and furans. In the case of the metal cadmium, even at very low concentrations this heavy element is toxic but its attachment to particulates increases their toxicity making them even more dangerous than those emitted from car exhausts.
Whilst the emission of nitric oxide and nitrogen dioxide gases is inevitable, given the presence of nitrogen in waste fuel and atmospheric nitrogen, it is important that such emissions are reduced by furnace design and by flue-gas controls. The removal of nitric acid from incinerators is only 60% effective and its subsequent conversion to nitrogen dioxide becomes problematic through the formation of smog and acid rain. Similarly, the effect of sunlight falling on volatile organic compounds (VOCs) and nitrous oxides causes the production of highly polluting ozone gas.
Whilst the ancient Greeks and Romans practised rudimentary forms of incineration to dispose of their waste, today’s growing emphasis on sustainable waste management comprising reduced waste generation, composting, and recycling, incineration is now often considered a last resort. To quote the 20th Century American social theorist Jeremy Rifkin, ‘Incineration is a false solution to the waste problem. It merely transfers waste from one form to another.’ Is it any wonder the price paid by the public for the disposal of municipal, industrial, radioactive, clinical and domestic wastes is ever increasing? .
Today the global drive toward sustainable technologies is commendable and a worthy cause, but it presents a number of social, economic, technological and political hurdles that need to be addressed and overcome. Perhaps the most pressing of these challenges comprises the world’s transition to renewable and green energy that requires industry to devise new creative solutions as evidenced by Lithium batteries becoming an integral part of our daily lives. The American multinational company, Tesla is accelerating the world’s transition to sustainable energy with electric cars but innovation is necessary to power this transition and the introduction of new battery technology, evidenced by a surging demand for Lithium ion batteries for use in everyday devices, gives rise to new risks. These batteries contain flammable electrolytes and if there are deficiencies in their engineering or manufacture, if they are re-charged incorrectly, or if they are damaged during use, they may burst into flames or explode. The burning question is, can incineration remain an effective and safe means of disposal for our future wastes? Part 2 of this paper, The Cost of Burnout, will examine and discuss this quandary.
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