jahangir jafari - M.Sc student in environmental sciences department of fisheries and environmental science
afshin danehkar - department of fisheries and environmental sciences
nematollah khorasani - department of fisheries and environmental sciences

havineg a great number of pipelines carrying hazardous gas oil and petrochemical materials iran is one the countries concerning most about the safety of the processes currently active in pipeline industries ad well as having many fragile ecosystems . keeping safe the surrounded environment of pipelines including built environment with respect to human health and natural environment as well , environmental risk assessment should be applied in order to estimate the aount of hazards and their probabilities of occurrence in the substrate of three phases of environment ; solid phaseliquid phase and gas phase. in this paper all common risk assessment tools being used in pipeline risk management would be provided in comparison to each other . there are so various methods that are used in pipeline risk assessment from a range of qualitative methods to the quantitative ones. having been organized more quantitative , the risk analysis and consequently the risk management would be more reliable . apart from being unreliable in all aspects merely qualitative methods are not appropriate DSSs decision support systems for risk management in environmental issures dur to the ecological complexities in the ecosystems as open systems.

environment , risk assessment , ERA,pipeline