There has been considerable variation in the DDT levers, based undoubtedly on significant differences in the variables explored, such as urban and rural differences, age of mothers, occupations, and geographic variability. He notes that despite the differences between studies, all reported that breast milk had such high levers of DDT that substantial percentages of nursing infants were ingesting more DDT than was considered acceptable by the World Health Organization.9 Calabrese states that cow's milk containing the average lever of DDT found in human milk would have been banned by the Federal Department of Agricultures While initial studies focused on DDT in the fate 1960s, other pesticides were identified in reviewing breast milk samples. Most of the studies concerning a spectrum of pesticides document that pesticides continue to be present in the milk of nearly all nursing mothers. The human breast is capable of producing a liter of milk a day. It is a complex organ that both synthesizes and excretes chemicals.
Milk is composed of protein, fat, carbohydrates, minerals, vitamins, hormones and antibodies.
Milk contains the fat as droplets suspended in water, an emulsion separated from. Chemicals can be excreted into breast milk by binding to milk protein or adhering to the surface of milk fat globules, or they can be totally contained within the fat globules. Fat soluble materials such as the organochlorines, DDT and chlordane, can be stored for long periods of time in maternal body fat. Body fat mobilization and turnover are increased during lactation and fat soluble substances may also be mobilized. Fat soluble substances may be released from fat during weight loss, which typically occurs during lactation.