The risk degree refers to the ratio of the number of ships with maritime accidents in a certain water area to the traffic flow in this water area. It is used to describe the degree of traffic hazards in specific sea areas. Due to the different tonnage and size of ships, the traffic flow in the waters should be weighted and converted according to the standard ships. The primary type of ship traffic accidents is collision accidents. Since ship grounding, rock striking and collision accidents can also be attributed to the collision between ships and fixed objects on and under water, the risk generally refers to the collision risk. [1]
In production safety activities, the degree of danger is caused by the possibility and severity of accidents.
Through the evaluation results of the first three stages comprehensive , analysis judge 、 Calculation The hazard probability (i.e. risk degree) caused by the chemical toxicant to be evaluated in the exposed population. (1) Analysis of risk characteristics of threshold chemical poisons
Expressed by the estimated danger degree
R=（EED/RfD）×10
EED - estimated total exposure of chemical poisons from various routes for high-risk population
The hazard is expressed by the exposure range (MOE): MOE=NOAEL or LOAEL/EED
(2) Analysis of risk characteristics of non threshold chemical poisons
1) Calculate lifetime (based on 70 years old) excess risk R:
R=1－exp[－（Q×D）]
Q - human carcinogenic intensity index calculated directly according to the data of population epidemiological survey
R -- lifetime probability of cancer caused by exposure to carcinogens (value is 0-1)
D -- individual daily average exposure dose rate, unit: mg/(kg · d) [2]
