Health and environmental risk assessment for road transport of hazardous material
Health and Environmental Risk
The first steps of the methodology are Problem Formulation, Data Collection/Evaluation and a Hazard Identification. Here it is crucial to have appropriate endpoints, and to assimilate enough information and knowledge on the area and chemicals. In order to identify the major risks and
to decide whether time-consuming quantitative methods are motivated, a rough analysis should be applied (e.g. an index method). If the risk is substantial scenarios can be selected based on the first steps of the methodology.
Initiation and Problem Formulation Preliminary endpoints
Hazard Identification Decision on further analysis and revision
of endpoint
Data Collection/Evaluation
Exposure Assessment Effect Assessment
Frequency and probability assessment for hazard/event
Risk Char acterization
Integration to Risk Management Risk Eval uation Risk tolerability decisions
Measure Risk analysis
Scope definition Hazard identification
Risk estimation
Risk re duction/control
Decision-making Imple mentation
Monitoring
RIS K ASS ESS MENT RIS K MAN AGEMENT
Risk e valuation
Risk tolerability decisions
Analysis of options Quantitative methods
Qualitative methods
Health and environmental risk assessment for road transport of hazardous material
The more quantitative analysis in the methodology described above should contain three estimations.
These are presented with examples below:
1. Frequency/probability estimation of acci-dent.
2. Effect estimation
3. Exposure estimation
In order to evaluate the three estimations they need to be transformed to a quantifiable risk value. This is often difficult due to the complexity of health and, especially, environmental risks. One possibility is to calculate a quota of predicted con-centration (exposure estimation) and a highest no adverse effect concentration (effect estimation).
This quota is a measure of consequence. But in order to measure risk frequency/probability esti-mation is also needed.
It is often quite straightforward to calculate a frequency for an accident resulting in a chemical spill, but the probability that the specific
environ-ment or individual is exposed remains to be assessed. This takes expertise from different fields. The uncertainty in the final risk charac-terization is therefore substantial but the sce-narios can nevertheless be placed in a risk matrix. An example for environmental risks is depicted below.
The advantage of placing the scenarios in a risk matrix is that it helps the risk control dis-cussions. It is even more important to get the control measures implemented. When several stakeholders participate in the risk manage-ment process, it is important that the commu-nication works and that there are functioning SHE management systems.
Part II
A case-study constitutes the second part of the report where a stretch of the road Sudurlands-vegur (in Iceland) is analyzed using the meth-odology from part I. Along the road there are vulnerable areas consisting of a water protec-tion area, a Salmon (salmo salar) river and a lake with Brown Trout (salmo trutta) and Arc-tic Char (salvelinus alpinus) fishing. Effects on these species constitute the endpoints of the environmental risk assessment.
The health endpoint is the water quality of the water protection area that supplies all the drinking water in Reykjavík. Reykjavík Energy delivers the water so they are stakeholders in this analysis. The chemicals in the analysis are gasoline and diesel. These were chosen partly because they are the most commonly trans-ported chemicals on the stretch and partly because they are the only chemicals that any transport data was available on.
Risk identification of the area is partly conducted with a qualitative Hazard
Distribution for (sm all) spill HT
0 0,002 0,004 0,006 0,008 0,01 0,012 0,014 0,016 0,018
1 2,05 3,1 4,15 5,2 6,25 7,3 8,35 9,4 10,5 11,5 12,6 13,6 14,7
V alues in 10^-2
PROBABILITY
Estimation, an index method. Based on this rough analysis the environmental and health hazards is substantial, therefore more quantitative methods are motivated. This identification step also aids the selection of scenarios.
Frequency and probability estimation is conducted by collecting data on the transports. A precision tree is constructed with three possible sizes of release for hazardous material transports and one for common heavy transports (equal to small haz-ardous material release). Due to lack of data fre-quencies can not be calculated for all scenarios.
The frequency calculations do not consider the exposure probability, i.e. the probability of esti-mated effects in case of spill.
The exposure estimation consists mainly of two chemical distribution calculations, one via the groundwater predominantly for the health assess-ment and one via surface water for the environ-mental assessment.
The health effect estimation assumes that the water quality is adversely affected if the concen-tration exceeds 0.1 mg/l. This value has been proposed by several oral sources, and is further
motivated by reference values presented by the Swedish environmental protection agency. The environmental effect estimation is more complex, and since no appropriate effect values could be found for any of the endpoint species the estimation becomes more qualitative since it must be based on the data available.
As far as possible a quotient can now be created of the results from the exposure estimation and the effect estimation to form a consequence measure. This is then combined with the frequency estimation in risk matrices of different levels.
Some of the results from the case study are presented in tables and related matrices below.
The risk exceeds the set criteria for both health and environment. The reason is mainly the extent of the consequences. It is left to the stakeholders to decide whether the set criteria are the right ones to ratify the judgments, and in that case which measures to take. Some recommendations are nevertheless given in the end of the report.
Health and environmental risk assessment for road transport of hazardous material Health risk characterization:
Environmental risk characterization:
Supplier Selection when Considering Risks for Disturbances in the Inbound Flow to Scania