cost efficiency of remediating arsenic-contaminated sites in sweden
DESCRIPTION
Written and prepared by me Hafez Shurrab. This report reviews an analysis to the one of environmental issues that cost-efficiency plays a significant role in.TRANSCRIPT
Cost-Efficiency of Remediating
Arsenic-Contaminated Sites in
Sweden - Written & Prepared
by Hafez Shurrab
I
ABSTRACT
This report reviews an analysis to the one of environmental issues that cost-
efficiency plays a significant role in. Many remediating activities are carried out by the
Swedish government to reduce the effects of contaminants by the industrial activities on
the environment and human health. The risk analysis the Swedish EFA adopts is an
explicit one that compares the levels of contaminants concentrations in each site to
predetermined guideline values. The analysis reviewed in the report discusses an implicit
approach, environmental medicine approach, which considers the actual exposure to the
risk, and therefore, the reduction in the risk to human health could be quantified and then
studied to examine several alternatives that may lead to more cost-efficient outcomes.
The analysis is based on studying 23 arsenic-contaminated sites, as arsenic is classified as
a primary contaminant. The reduction of risk is measured by the number of saved lives,
which implies that the risk assessment method is driven by health effects. The results
indicate that at 23 contaminated sites, the cost per life saved varies from SEK 287 million
to SEK 1,835,000 million, and show that the level of ambition is high. Thus, it is
recommended to open deep discussions on cost-efficiency methods of risk assessment
before going further any remediation, to achieve the objective in more cost-efficient
ways, prioritize the right sites that have more hazardous levels, and increase the number
of lives to be saved allocating similar amounts of resources.
II
TABLE OF CONTENTS
ABSTRACT ................................................................................................................................ I
TABLE OF CONTENTS ...........................................................................................................II
LIST OF TABLES .....................................................................................................................II
1. INTRODUCTION ..........................................................................................................- 1 -
2. BACKGROUND ............................................................................................................- 2 -
3. THEORY ........................................................................................................................- 3 -
3.1. Arsenic Concentrations ....................................................................................................... - 4 -
3.2. Exposure .............................................................................................................................. - 5 -
3.3. Accessibility and Land Use ................................................................................................. - 5 -
4. METHODOLOGY .........................................................................................................- 5 -
4.1. Risk Assessment .................................................................................................................. - 5 -
4.2. Calculating the Number of Cancer Cases Avoided ............................................................. - 6 -
5. RESULTS .......................................................................................................................- 7 -
6. CONCLUSIONS .............................................................................................................- 9 -
1. REFERENCES .............................................................................................................- 10 -
LIST OF TABLES
Table 1 - The cost per life saved for primary prevention measures .......................................- 2 -
Table 2 - Site-specific characteristics. ....................................................................................- 3 -
Table 3 - Site-specific characteristics .....................................................................................- 4 -
Table 4 - Quantified cancer risks, descriptions and sources. .................................................- 7 -
Table 5 - Number of saved lives, costs and comparisons ......................................................- 8 -
- 1 -
1. INTRODUCTION
Some of industrial activities leave pollutants that have serious impacts on human
health and the environment. The level of pollutants varies among the contaminated sites.
Since there are sites that have the seriously harmful levels of pollutants to human health
and the environment in terms of contaminant concentrations, the Swedish Environmental
Protection Agency (EPA) has prioritized 1500 sites to be remediated as part of striving to
mitigate the risk to human life. A plan has been set so that all those contaminated sites
have to be remediated by 2050. The most harmful sites required remediation may cost
SEK 60,000 million approximately cost to mitigate the potential risks (Swedish EPA,
2008). The government allocates around 10% of the annual national funds for
environmental protection to remediate the contaminated sites, which are estimated at
about 455million per year (Gov. Bill, 2007). The Swedish EPA adopts a method of risk
assessment in which they set standards (guideline values) that represent the worst
acceptable exposure situation to risk on an individual. This means that the actual
exposure to the risk by individuals in such sites is not the main concern, which may result
in remediating locations where there is no actual exposure, and hence spending much
money ineffectively. The valuation of risk reduction is not possible in this case, since the
expected risk is not quantified. Therefore, the estimation of how much money a specific
amount of risk reduction costs is not possible.
The main objective of this paper is to review an analysis (Forslund et al., 2010) on
the remediation of arsenic-contaminated by valuing the risk implicitly. The effect to be
studied is the cancer cases that arsenic-contaminated sites may cause (Forslund et al.,
2010). The main purpose is to see the arsenic risk management in wider perspective of
live-saving interventions. The large risks should not be given a same attention as small
risk. The remediation of contaminated sites cost much money. Thus, any overestimation
of risk on lifesaving contributes in reducing the cost-effectiveness. Lifesaving is used as a
measure to reflect the amount of reduced risk. The analysis includes a method for the
estimation of site-specific cancer risks and calculations of cost per life saved. The results
show that the remediation costs much higher per life saved than that associated with other
primary prevention measures, which indicates that the ambition level of Swedish
remediation may be too high.
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2. BACKGROUND
One of the most important issues in cost-effectiveness is the resources allocation. It
is very critical to spend money so that to save as many lives as possible. Since the life
valuation is controversial issue, the analysis is based on estimating the number of saved
lives implicitly, rather than using some predetermined explicit values. The average cost
of lifesaving varies from USD 470 to USD 1,245,000 (in 1993 prices) (Ramsberg &
Sjöberg, 1997). Table 1 shows the cost per life saved for primary prevention measures.
The implicit cost per life saved is, on average, SEK 66.6 million, with a large variation
among different sectors from SEK 68,000 to SEK 675 million. The median cost per life
saved is approximately SEK 12 million. The comparison between such method and the
guideline values, the Swedish EPA uses, shows that there are 100–1000 times higher
accepted risks in working and housing environment than contaminated sites (Rosén et al,
2006).
Table 1 - The cost per life saved for primary prevention measures in Swedish crowns, SEK (2007 prices) (source: (Forslund et al., 2010)).
The allocation of resources is considered to be cost-efficient when the marginal cost
is equal to the abatement cost (interventions). Thus, if the marginal costs differ, resources
should be reallocated to the sector with the lowest marginal costs. It would be possible in
the US to save an additional 60,000 lives per year through a more cost efficient allocation
(Tengs & Graham, 1996).
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3. THEORY
The government gives the priority to sites, out of the 1500 contaminated sites,
contaminated with the most hazardous contaminants, which are called primary
contaminants. Arsenic (26%) has been identified as the most hazardous carcinogenic
(IARC, 2004, 2008) contaminant among other metals. Table 2 & 3 lists the 23 arsenic-
contaminated sites with either completed (10 sites) or on-going measures (13 sites).
The exposure to arsenic increases the risk of developing cancer (U.S. Department of
Health and Human Services, 2007). There are many industrial activities that produce
arsenic contaminants such as glasswork and sulphate and metal industries, wood
impregnation, and from sawmill.
Table 2 - Site-specific characteristics (source: (Forslund et al., 2010)).
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Table 3 - Site-specific characteristics (source: (Forslund et al., 2010)).
3.1. Arsenic Concentrations
Since the exposure to arsenic is a harmful in the long term, the arsenic concentrations
have been collected before the remediation to estimate the average concentrations of
arsenic in the 23 sites (Forslund et al., 2010). The remediation should reduce such
concentrations to specific safe limits. There are some factors that play a significant role in
the determination of safe limits of arsenic concentration such as the number of
individuals exposed, geographical locations of the sites, the accessibility (open or
enclosed), and the land use (housing, recreation, or industry) (Forslund et al., 2010). As
shown in Table 2 & 3, there safe limit of objectives of the average concentration
correspond the Swedish EPA's guideline values for either sensitive, i.e. 15 mg/kg, or less
sensitive, i.e. 40 mg/kg, land use (Forslund et al., 2010).
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3.2. Exposure
The exposure is estimated by gathering information about the individual population,
which is of course available in the municipal bodies. The population of individuals
exposed to the contaminated sites is divided into three classes, 1–10, 10–100 and 100–
1000. Other types of information have been gathered such as the land use and the number
of children aged from 0-3 years (Forslund et al., 2010).
3.3. Accessibility and Land Use
As the accessibility to the contaminated sites is divided into open or enclosed sites,
the daily exposure is estimated to be 1 h for recreational activities, 24 h for individuals
residing on or adjacent to a site, and 5.7 h for occupational activities. In case that these
factors are neglected, the underestimation possibility of risk for some sites results in
overestimating the number of lives saved, and, in other words, underestimating the cost
per life saved (Forslund et al., 2010).
4. METHODOLOGY
The cost-effectiveness analysis is a primary part in the overall analysis, as the
environmental effects were not quantified by the Swedish EPA. Moreover, the cost-
benefit analysis is also important to include other environmental benefits may be brought
by the remediation (Forslund et al., 2010).
4.1. Risk Assessment
The main task of risk assessment is to determent the levels of arsenic exposure and
their effects on the environment and human health when additional contaminant resources
are present. The Swedish EPA classifies risk through estimating the contaminant level in
the site, site’s environmental sensitivity, and protection value (Swedish EPA, 2002). The
guideline values for contaminant are compiled in the soil for different for different types
of land use, to make the risk assessment more obvious. These are national values and
mark the levels that should not be exceeded. The sub questions arise then are what human
health risks arise at a specific level of exposure and what the actual exposure is at a
specific site (Forslund et al., 2010).
The health risk assessment could be estimated by referring to the tolerably daily
intake (TDI) that World Health Organization and other international bodies recommend.
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The TDI refers to the daily amount of a chemical that has been assessed safe for human
being on long-term basis (usually whole lifetime) (Forslund et al., 2010). There are two
categories for the sensitivity of land use, sensitive and less sensitive. For sites with less
sensitive land use, the types of exposure or exposure pathways include dermal contact
with contaminated soil, direct intake of contaminated soil and inhalation of dust from the
contaminated site. The relevant exposure pathways for sites with sensitive land are
dermal contact, direct intake of soil, intake of groundwater, inhalation and intake of
vegetables and fish. The Swedish EPA uses a precautionary principle to handle all
uncertainties in the risk assessment. In order not to underestimate the risks, three
considerations are taken including: (1) the contaminant levels should represent a ‘bad but
possible scenario; (2) possible but less probable circumstances that could increase the
risks are considered; and (3) conservative values should be chosen for the parameters in
the risk assessment (Swedish EPA, 2007).
The Swedish EPA does not quantify the expected risk reduction, which leads to a
need to value the risk before and after the remediation in terms of relevant measure, for
instance the number of cancer cases avoided (Forslund et al., 2010).
There are two main differences between guideline values approach, the Swedish
EPA adopts, and the medicine approach. The later one assesses the health risk to a larger
extent, but over shorter time period, two decades, while the Swedish EPA aims to strives
for long-term sustainability and argues that 100–1000 years should be considered
(Liljelind & Barregard, 2008). Another difference is that environmental medicine treats
high concentrations of contaminants on the surface more seriously than contaminants
deeper down that humans normally do not risk being exposed to, except for the case of
ingestion of ground water (Forslund et al., 2010).
4.2. Calculating the Number of Cancer Cases Avoided
The analysis studies the exposure through pathways including ingestion of soil,
inhalation of air, and skin contact, since the exposure through intake of vegetables is not
relevant for the contaminated sites, and the exposure through ingestion of groundwater is
limited to two of the sites. The exposure through all pathways is considered for
calculations. Every pathway has different method of calculation. For skin contact case,
the assumptions for skin absorption percentage when contacting an amount of soil guides
to draw calculations for the exposure to arsenic. The reaction between the type of soil and
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the air is assumed and studied to estimate the concentration of arsenic in air particles. For
ingestion of soil, the arsenic exposure is calculated based on assumptions of the amount
of intake during the exposure time. The uncertainties are expressed about in intervals of
certain factor so that the values of the intervals lead to the highest exposure, which
implies that the calculations are conservative. Using different method, the number of
saved cancer cases would be several times lower if mid-interval estimates are considered
instead (Forslund et al., 2010). The calculations are done in two steps, as the number of
saved cancer cases are calculated in case of the absence of the remediation for 30 years
(Viscusi et al., 1997). Then the risk is estimated in case of the presence of remediation,
according to the Swedish EPA's guideline values. The number of lives saved should be
adjusted since not all cancer cases lead to death. Since the future cancer cases are
unknown, they are not discounted (Hamilton & Viscusi, 1999). Table 4 shows the
quantified cancer risks in terms of concentration for each exposure pathway.
Table 4 - Quantified cancer risks, descriptions and sources (source: (Forslund et al., 2010)).
5. RESULTS
After doing the calculations to the 23 sites, the results illustrated in Table 5 shows
that the highest value of expected number of saved lives through the remediation are 0.03
live, 0.12 lives in total SEK 881 million. The cost per life saved on the arsenic sites varies
from SEK 287 million to SEK 1,834,000 million (Forslund et al., 2010). This widely
exceeds the value of a statistical life (VSL), which in Sweden is considered to be about
SEK 21million (SIKA, 2005). One more significant note is that 72% of the health effects
occur at three sites (Tvärån, Glasbrukstomten, Konsterud), where remediation costs
amount to 13% of the total remediation costs, which clearly shows the priority concern in
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the remediation work. The average cost is calculated as the quotient between the total
remediation cost and the total number of cancer cases avoided (or lives saved). The
number of individuals need to be exposed at each site in order for one life to be saved is
calculated as well, which results that of individuals exposed should increase from 10–
1000 to 2850–620,000 individuals. Such populations exceed the number of inhabitants in
the municipality in some cases. The calculations also reflect that the ambition level in
remediation is high, and in some cases unreasonably high. There may be other concerns
associated with the other risks arsenic may cause such as chronic diseases. The
environmental risks differ among sites and are very difficult to estimate and value. This
analysis explains why the cost per life saved varies so much between the sites.
Differences in environmental risk reductions between the sites could be one of the main
reasons for variety (Forslund et al., 2010).
Table 5 - Number of saved lives, costs and comparisons (source: (Forslund et al., 2010)).
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6. CONCLUSIONS
The remediation of the contaminated sites is a complicated process and associated
with many considerations. The Swedish EPA should adjust both the priorities given to the
sites and the level of ambition. The most hazardous sited should be prioritized. The cost
per life for the examined sites under a 30 year period amounts varies between SEK 287
million and SEK 1,835,000 million even though the calculations underestimate the cost.
The statistical life value amount to SEK 21 million (SIKA, 2008), while the average cost
per life saved amounts to SEK 7200 million, which is very high. It is highly
recommended to conduct a discussion about the allocation of resources across different
sectors to save lives. For the number of lives to be saved, the results shows that no more
than 0.12 lives will be saved during a 30 year period at a cost of SEK 880 million. The
approach that the Swedish EPA adopts in risk assessment is setting guideline values and
then assesses whether the contaminant concentrations exceed these values, while the
actual exposure at risk is not really taken into considerations. As there is absence of
estimating the reductions of remediation's risk, it is not possible then to quantify the
remediation benefits. This explains the low cost-efficient measures of remediation the
Swedish EPA adopts, as they are more costly measures than needed to reach acceptable
risk levels. This justifies the need to use a new method for making risk valuations.
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1. REFERENCES
IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. (2004). Some
drinking-water disinfectants and contaminants, including arsenic (Vol. 84). World
Health Organization.
IARC. (2008). Overall evaluations of carcinogenicity to humans. International Agency
for Research on Cancer.
Forslund, J. Samakovlis E. Johansson M., & Barregard L. (2010). Does remediation save
lives? — On the cost of cleaning up arsenic-contaminated sites in Sweden. Science of the
Total Environment. 408 (16), 3085-3091.
Gov. Bill (2007). Budgetpropositionen för 2008.
Hamilton, J. T., & Viscusi, W. K. (1999). Calculating risks?: The spatial and political
dimensions of hazardous waste policy (Vol. 21). MIT Press.
Liljelind I. Barregard L. (2008). Hälsoriskbedömning vid utredning av förorenade
områden. Swedish Environmental Protection Agency Report (Vol. 5859).
Ramsberg, J. A., & Sjöberg, L. (2006). The cost-effectiveness of lifesaving interventions
in Sweden. Risk Analysis, 17(4), 467-478.
Rosén, L. Söderqvist, R. Soutukorva, Å. Back, P-E. Grahn, L., & Eklund, H. (2006).
Riskvärdering vid val av åtgärdsstrategi. Swedish Environmental Protection Agency
Report (Vol. 5537).
SIKA. (2005) Effektiva styrmedel för säkrare vägtrafik, 8. Swedish Institute for
Transport and Communications Analysis PM 2005.
Swedish EPA. (2002). Methods for inventories of contaminated sites. Swedish
Environmental Protection Agency Report (Vol. 5053).
Swedish EPA. (2007). Rapport riskbedömning av förorenade områden—En
vägledningfrån förenklad till fördjupad riskbedömning. Swedish Environmental
Protection Agency.
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Swedish EPA. (2008). Lägesbeskrivning av efterbehandlingsarbetet i landet 2007 —
Bilagor. Swedish Environmental Protection Agency official document.
Tengs, T., & Graham, JD. (1996). The opportunity cost of haphazard social investments
in life-saving. In: Hahn, RW. Risks, costs and lives saved. New York: Oxford University
Press.
U.S. Department of Health and Human Services. (2007). Toxicological profile for
arsenic. Public health Service, Agency for Toxic Substances and Disease Registry.
Viscusi, W. K., Hamilton, J. T., & Dockins, P. C. (1997). Conservative versus mean risk
assessments: Implications for Superfund policies. Journal of environmental economics
and management, 34(3), 187-206.