In order to decide the priority of prevention activities in environmental pollution, a study must be carried out in the wide spectrum of causes and effects of pollution particularly effects on humanbeing in the concept of environmental engineering and toxicology Therefore, a study must be covered various segments of environment such as air, water/sea water, wastes and soil in other words sources of pollution should be analysed in the view point of intergrated efforts of engineering and toxicology to locate high priority of prevention activities which given the high value of human health.