Integrated environmental and health impact assessment of waste management
- The text on this page is taken from an equivalent page of the IEHIAS-project.
The potential environmental and health effects of waste management of municipal solid waste (MSW) are poorly understood, especially when the different aspects of the full chain process (waste production, collection, transport, recycling, treatment, disposal) are taken into consideration.
Scope
Description
A prognostic assessment was carried out in Lazio (a region in Central Italy with about 5.5 million inhabitants including Rome) by comparing two future waste management scenarios based on appropriate sustainable measures to the baseline situation representing the business as usual situation. The following full chain approach was considered.
Scenario(s) and type of assessment
We evaluated the 2008 baseline scenario (BS) and two alternative 2016 scenarios, Waste Strategy (WS) and Green Policy (GP).In the first alternative scenario (WS), waste management was modified because of an increase in recycling/composting, different waste flows, cleaner transportation, new management plants and no landfilling without pre-treatment. In the second alternative scenario (GP), an additional drastic reduction in the total amount of waste was foreseen together with a very high recycling rate.
Geographical and temporal scope
The study was carried out for the Region of Lazio (Central Italy, it includes the city of Rome) with 5,561,017 inhabitants (as at January 1st 2008). Lazio is characterized by a strong heterogeneity in the distribution of population: more than 75% of residents are concentrated in the province of Rome, particularly in the city of Rome where about 2.7 million people live (49% of regional population). However, most of the municipalities (54% of total) have less than 3.000 inhabitants, with only 13.2% of municipalities having more than 15.000 residents. The Lazio average density is 323 inhabitants/km2, higher than the national density (199inhabitants/km2) Population data at the smallest unit of aggregation for census 2001 were available in Lazio by census block (CB) (total of 27,875 CB (mean 183, SD 234 inhabitants per unit)).
Since the scenarios will be fully operating in 2016, we decided to perform the assessment considering the 35-year period 2016-2050 for the calculation of the health impact. In particular, for the calculation of the effect of transportation on survival (and Years of Life Lost – YLL- and Disability Adjusted Life Years- DALY), we assumed that the exposure to trucks emissions will be operating for the period 2016-2030 (and health effects were calculated up to 2050). Similarly, we assumed that incinerators/gasification plants operating in 2016 will be operating until 2030 and the health effects were estimated up to 2050. For landfills operating in 2016, we assumed that the emissions will last up to 2045 (30 years) and the effects on newborns were calculated up to then (an assumption in agreement with the available knowledge that landfilled biodegradable waste starts to emit biogas a few years after deposit and continues to do so for several decades).
Environmental and health factors
The following pollutants/factors were included within the scope of this assessment:
- Particulates and gases (PM10, NO2) from transport, incinerators, landfills engines
- Dioxins and other combustion products from incinerators
- Bioaerosols (endotoxins) from MBTs and landfills
- Biogas from landfills
- Odours from MBTs and landfills
- Occupational injuries from waste collection and transport
The following health outcomes were considered:
- Mortality (mainly respiratory and cardiovascular) from PM10,and NO2 from transport, incinerators, and landfills engines
- Adult cancers from emissions of incinerators
- Congenital malformations and low birth weight from landfills
- Respiratory symptoms from MBTs and landfills
- Occupational injuries from waste collection and transport
- Odour annoyance from MBTs and landfills
All these outcomes were combined to calculate Disability Adjusted Life Years (DALYs).
Stakeholders
The full list of stakeholders includes:
- European, national and regional policymakers and authorities (Ministries of Environment, Ministries of Health)
- Institutions for environmental control and public health
- Transportation industry
- Waste management companies and industry
- Consumers, NGOs and lobby groups (e.g. for composting and recycling)
- Citizens associations
- Media
- Researchers
Assessment methods
Exposure assessment
The population under evaluation were residents in Lazio, and, in particular, people living in Rome potentially exposed to exhaust fumes from waste collection and transport. We also considered the population living close to Mechanical and Biological Treatment (MBT) plants (200 meters), landfills (2 km) and incinerators (3 km) as well as workers in the waste industry for the risk of occupational accidents.
Pollutants from transport, emissions from incineration, and combustion of landfills biogas were evaluated. Concentrations of specific pollutants (PM10 and NO2) were modelled using ad hoc GIS models and the ADMS-Urban model. Population-weighted exposure levels were calculated. Concentration-response functions were derived from systematic reviews of the literature.
Health effect assessment
Cases of specific diseases and disorders attributable to waste management (incidence of cancer, newborns of low-birth weight, congenital anomalies, and prevalence of respiratory disorders and odour annoyance) were calculated.
Impact Assessment
Years of Life Lost (YLL), and Disability Adjusted Life Years (DALYs) were estimated for the 35-year period from 2016 to 2050.
Uncertainties
We have listed the sources of uncertainties for each step of our evaluation. Significant sources of uncertainty were assessed according to the IPCC (2005) classification. The level of confidence was systematically recorded for each step in the assessment indicating correctness of each model, analysis or statement using value out of 10 where: 9 is very high confidence; 8 is high confidence; 5 is moderate confidence; 2 is low confidence; and <2 very low confidence.
Results
Main findings
Waste management and emissions. At the baseline the total volume of waste produced was 3.330 mTonnes, of which 0.593 was recycled/composed, 1.902 was landfilled without pre-treatment, and 0.835 was managed with Mechanical and Biological Treatment (with production of Refuse Derived Fuels (RDFs) for incineration). Under the Waste strategy, the recycling/composting rate will be increased up to 60% and no landfill will be in use without pre-treatment. Under the Green policy, the amount of waste production will decrease to 15% and recycling/composting rate will increase to 70%. A considerable decrease (up to 90%) will be seen for most of the emitted pollutants (for instance particulate matter (PM) emissions will go from 17.9 to 6.6 and 4.13 tonnes/year for the three scenarios, respectively)
Population. A total of 36,191 people were living nearby MSW facilities at baseline (23,917 close to the two incinerators, 2,345 close to MBTs, and 9,929 close to landfills). With the Waste strategy, the number of people living close to plants will increase to 51,639 subjects, mainly due to the introduction of new incinerators (from 23,917 to 39,284 subjects). On the other hand, the Green policy will decrease to 14,606 the population involved with an important reduction of people residents close to incinerators and landfills. Important differences by socioeconomic status were present at baseline, with people of lower socioeconomic status being relatively more exposed to waste management than more affluent people. In addition to the general population, waste workers were estimated: about 10,000 for the baseline and the Waste strategy whereas the number will decrease to about 8,300 workers under the Green Strategy.
Pollution from transport and management plants. At baseline, a total of 18,916 journeys of trucks per year were necessary in Rome for the transfer of waste from the resident areas to the management facilities. Under the baseline scenario, about 10 millions Kilometers per year were travelled. In the Waste strategy, the number of journeys and the kilometers travelled are reduced of 37.2% and 38.2%, respectively. The reduction was even more radical in the Green policy scenario, with a reduction of 65.3% in journeys and 64.5% in kilometers travelled. The contribution of waste transport to the average annual concentration of NO2 in Rome was 0.0199 µg/m3 at baseline, 0.00198 µg/m3 with waste strategy and 0.00118 µg/m3 with the green policy with an important reduction of the population weighted exposure (-90%, -95 %, respectively). Estimated annual average concentrations of air pollutants emitted from the plants in the vicinity of landfills and incineration plants were rather small. The population weighted NO2 (and PM10) exposure levels were also relatively low, ranging from 0.05 to 0.7 µg/m3 for landfills and 0.03 to 0.06 µg/m3 for incinerators.
Attributable cases. An annual frequency of 243 occupational injuries in the waste sector was estimated, with 0.8 fatalities each year; the absolute number of accidents will decrease in the Green Policy because of the reduction of the manpower. The impact of transport of waste on the population of Rome could be estimated in 561 (related to NO2 exposure) and 14 (related to PM exposure) Years of Life Lost (YLL) at baseline; the impact as YLLs decreases to 50 and 1 (waste strategy) and to 29 and 0 (green policy), respectively. For MBTs,the prevalence of subjects with severe odours annoyance (about 130 subjects) and the prevalence of people with respiratory symptoms attributable to the plants (about 500 subjects) was constant in all the scenarios. For incinerators, the cumulative incidence of attributable cancer cases over the 35 year period was 7.5, 11.7and 2.5 in the three scenarios, respectively. A total of 10 YLL (NO2) attributable to incinerators were estimated at baseline. The number increased to 15.9 YLL with the waste strategy and decreased to 9.6 with the green policy. The YLL attributable to PM were very small. For landfills, low birth weight cumulative incidence was 8.3 newborns (baseline and waste strategy) and 2.8 in the green policy. The cumulative incidence of congenital anomalies was of 0.3 subject (baseline and waste strategy) and 0.1 for the green policy. The health impact of landfills as YLL was 17.9 (NO2) estimated at baseline and with waste strategy and a decrease to 12.4 with the green policy. The prevalence of severe odours annoyance and respiratory symptoms assessed for residents at 200 meters from the landfills, were the same (54 and 424, respectively) at the baseline and with the waste strategy while a decrease to 19 and 147 were predicted with the green policy.
DALYS. The most important health impact of waste management was occupational accidents, responsible of about 40,000 DALYs for the baseline and the Waste strategy while the impact decreases to 33,000 DALYs with the Green policy. For the general population, a total of about 3000, 2500, and 1600 DALYs were estimated under the different scenarios, respectively. The largest contribution to DALYs for the general population was from respiratory symptoms (about 90%) and odour annoyance; the contribution from the other health disorders was small.
Appraisal
Implications
The environmental health impact of waste management was moderate when compared to other potential environmental factors. Few aspects should be underlined:
- the most important heath impact of waste management is occupational accidents related to the collection, load and transport of waste.
- the possible role of transport of waste with highly polluting trucks is often neglected in the discussion of waste management related health problems.
- a relevant health impact was estimated from landfills and MBTs with regards to respiratory symptoms and odour annoyance. This is not surprising as the perception of these aspects is the basis for community concerns over waste management plants.
- the environmental and health impact generated from traditional management plants like landfills and incinerators is limited due to the strict legislation on emissions.
- significant improvement in the environmental and health impacts can be achieved with future strategies dedicated to waste reduction, recycling, clean transport, composting and waste treatment before the final destination.
However, our findings suggest an important equity issue as there is a differential distribution by social class for people living close to management plants. The same happens for occupational injuries among workers. Since the equity issue is not solved in relative terms even in the most radical Green strategy, more attention should be posed to that in waste management planning and operation.