Introduction to Contaminated Site Management - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 59

1.7.11 Cost-Benefit Analyses
A different way of looking at Risk Management relies on cost-benefit analyses ,
weighing the expected costs against the expected benefits (e.g., Crettaz et al. 2002 ;
Edejer et al. 2003 ). It is often difficult to quantify the benefits of Risk Management
solutions. Grosse et al. 2002 , for example, estimated the economic benefits from
projected improvements in worker productivity, resulting from the reduction in chil-
dren's exposure to lead in the United States since 1976. The authors showed that
because of falling lead-blood levels, USA preschool-aged children in the late 1990s
had IQs that were, on average, 2.2-4.7 points higher than they would have been if
they had the blood lead distribution observed among preschool-aged children in the
USA, in the late 1970s.
A cost-benefit analysis necessitates that costs and benefits should be expressed
in the same units, usually in the unit of money (e.g., euros or US dollars). Generally,
a Risk Management solution is beneficial when the value of the benefits is higher
than the value of the costs. An optimal Risk Management solution seeks the most
optimal (highest) 'value of benefits/value of costs' ratio. Since human health effects
are difficult to monetarise, health effects often are expressed as DALYs, that is, a
measure for the overall disease burden defined as the sum of the years of life lost
due to premature mortality in the population and the years lost due to disability
(WHO 2009 ).
Cost-benefit analyses are also used to evaluate Risk Management projects.
1.7.12 Integration of Human Health and Ecological
Risk Assessment
Human Health and Ecological Risk Assessment mainly developed independently of
each other. Certainly in the pioneer years of risk-based soil quality assessment, only
experts from the respective disciplines were concerned with either Human Health
or Ecological Risk Assessment. The role of generalists, who could have promoted
integration, was limited during this phase. Another reason for the independent devel-
opment is that in most countries Human Health Risk Assessment was developed
earlier than Ecological Risk Assessment.
In the last few years, there has been a trend with regard to making a case for a
stronger link between Human Health and Ecological Risk Assessment (WHO 2001 ;
Suter et al. 2005 ). The UNEP/ILO/WHO International Programme on Chemical
Safety (IPCS) formulated two fundamental reasons for the integration of Human
Health and Ecological Risk Assessment, in the framework of the production, use,
transport and disposal of chemicals (WHO 2001 ). First, it improves the quality
and efficiency of assessments through the exchange of information between human
health and environmental risk assessors. And, second, it provides more coherent
input into the decision-making process. Indeed, in several risk-based frameworks
different values are used for important input parameters, such as the Koc (organic