Estimating health effects: waste

The text on this page is taken from an equivalent page of the IEHIAS-project.

As part of the EU-funded INTARESE project, which contributed to the development of this Toolbox, a series of case studies was undertaken to assess health impacts associated with waste collection, transport and treatment, under different waste management scenarios. One of these focused on the Lazio area of Italy.

Exposures considered were airborne particles (PM₁₀), nitrogen oxides (NO_x) and odours from landfill sites, mechanical biological treatment works (MBTs) and incinerators, and associated waste transport. Waste management scenarios covered the period up to 2050. Health endpoints of interest included cancer, low-birth weight, congenital anomalies, respiratory disorders, odour annoyance, and occupational injuries.

Cases of these diseases and disorders attributable to waste management were estimated for the 35-year period from 2016 to 2050, using concentration-response functions derived from the systematic review of the literature. The procedure used was as follows.

1. Background sex-age specific cancer incidence data were retrieved from the pool of the Italian cancer registries. Mortality statistics were available from the Italian Institute of Statistic; prevalence of congenital malformations at birth was derived from the Annual Report (data for 2000) of the International Clearinghouse for birth defects monitoring system for Italy; background prevalence data for respiratory symptoms in the adult population and odour annoyance were derived from the study by Herr et al (2003). Rates of occupational injuries we derived from a UK report (HSE, 2009).
2. The health metric for each of the following outcomes was the annual cumulative (2016-2050) number of case/diseases attributable to waste management (attributable burden):
   • Annual and cumulative incidence of cancer in adults
   • Annual prevalence of congenital malformations in children and cumulative incidence of cases
   • Annual prevalence of low birth weight and cumulative incidence of cases
   • Annual mortality
   • Annual prevalence of respiratory disorders
   • Annual prevalence of odours annoyance
   • Annual incidence of occupational injuries
3. Exposure-response functions (ERFs) for PM₁₀ and NO₂ were taken from the systematic review conducted as part of a related INTARESE study on transport. They thus relate specifically to traffic-related air pollution. For a 10ug/m³ increase in outdoor PM₁₀ concentrations, the relative risk (RR) for all natural mortality is 1.060 (95%CI 1.030-1.090). For a 10 ug/m³ increase in NO₂, RR= 1.06 (95%CI=1.04-1.08).
4. For morbidity, ERFs were obtained from a systematic review of the literature on waste (Porta et al. 2009). This provided relative risks for the following outcomes:
   • Cancer cases near incinerators (within 3 km): RR=1.035 (95% CI=1.03-1.04) (Elliott et al. 1996). This effect was scaled in the cancer model according to plant and population characteristics;
   • Respiratory symptoms (cough on rising and during the day) near MBTs (200 metres) or landfill sites (200 metres): OR=3.18 (95% CI 1.24 to 8.36) which is equivalent to a prevalence rate ratio= 2.25 (Herr et al. 2003);
   • Low birth weight near (2km) landfill sites: RR=1.06 (99% CI=1.052-1.062) (Elliott et al. 2001). This coefficient was halved on the assumption that the methods to capture biogases from landfills had been improved over the years;
   • Congenital anomalies near (2km) landfill sites: RR=1.02 (99% CI=1.01-1.03) (Elliott et al. 2001). This coefficient was likewise on the assumption that the biogas capture from landfill had been improved over the years;
   • Severe odour annoyance near MBTs (200 metres) or landfill sites (200 metres): 5.4%
5. For occupational injuries, accident rates (per 100.000 workers in the waste industry) were obtained from a comprehensive survey undertaken in the UK (HSE, 2009). This gave:
   • Fatality rate: 8.5
   • Major injury accident rate: 423
   • Over 3 days injury accident rate: 2093
   • Total accident rate: 2525
6. For each scenario and for each source/process, estimates were made of:
   • Attributable cases (n)
   • Years of life lost (YLL)
   • Disability adjusted life years (DALYs)
7. For this purpose, first, exposure classes were defined and the attributable cases calculated:

   AC = Rateunex * ER * Popexp

   where

   AC = the attributable number of cases

   Rateunex = background prevalence/incidence rate in the general population

   ER = excess risk in the exposed population (relative risk – 1)

   Popexp = number of exposed subjects

8. Years of life lost (YLL) attributable to PM₁₀ and NO₂ exposure from transport and plant emissions were estimated, projected forward to the years 216 and 2050. The assumption was made that the population living close to emission sources throughout this period, and their underlying mortality rates, were similar to that of the national population in 2005. Calculations were done using the spreadsheets provided by the Institute of Occupational Medicine.
9. DALYs were calculated for Calculating DALYs:waste the three scenarios. Attributable cases were converted to DALYs by including severity weights (S) and the duration of the health state (D):

   DALY = AC * D * S

   • Note: The severity weights (or disability weights, S) give an indication of the reduction in capacity due to the specific disease. Weights vary from 0 (healthy) to 1 (death), and are typically determined by experts (clinicians, researchers, etc). In this case, severity weights were generally derived from the Victorian Burden of Disease Study (2005). The following specific severity weights/and duration of disease (D, years) were adopted:

Outcome	Severity weight (S)	Duration (D), years
Mortality	1	-
Cancer	0.44	12.6
Respiratory symptoms	0.08	1
Low birth weight	0.106	79.6
Congenital anomalies	0.17	79.6
Severe odour annoyance	0.03	1
Occupational injuries: fatal	1	-
Occupational injuries: major injury	0.208	37.3
Occupational injuries: over 3 days injury	0.10	3.3

References

• Elliott, P., Briggs, D., Morris, S., de Hoogh, C., Hurt, C., Kold Jensen, T., Maitland, I., Richardson, S., Wakefield, J. and Jarup, L. 2001 Risk of adverse birth outcomes in populations living near landfill sites. British Medical Journal 323, 363–368.
• Herr, C.E., Zur Nieden, A., Jankofsky, M., Stilianakis, N.I., Boedeker, R.H. and Eikmann, T.F. 2003 Effects of bioaerosol polluted outdoor air on airways of residents: a cross sectional study. Occupational and Environmental Medicine 60(5), 336-342.
• HSE 2009 Update to mapping health and safety standards in the UK waste industry. London: Heath and Safety Executive.
• Porta, D., Milani, S., Lazzarino, A.I., Perucci, C.A. and Forastiere, F. 2009 Systematic review of epidemiological studies on health effects associated with management of solid waste. Environmental Health 8, 60.
• Victorian Government Department of Human Services 2005 Victorian burden of disease study – mortality and morbidity in 2001. Melbourne: Public Health Group, Rural and Regional Health and Aged Care Services Division. Victorian Government Department of Human Services. Melbourne Victoria, 210 pp..