Factors affecting on heavy metals and (PCBs) in milk and milk products

Milk is a primary source of nutrients in diets all around the world . Technical progress, various industrial activities and increased roadway traffic resulted in significant increase of environmental contamination .By their spread speed in biosphere and increasing concentrations heavy metals and PCBS are considered to be among the most hazardous pollutants.In mammals the major routes of elimination are biliary and through the milk, so this product is used as a biological indicator of the degree of environmental pollution.