Man has seriously polluted land, sea and the air ( and even space). Therefore all our foodstuffs are subject to pollution. For example fish contain mercury and lots of other chemicals . Plants contain pesticides and other "cides" ,but most will wash off and meats contain pesticides, growth hormones, antibiotics ,steroids and chemicals to keep the dead body part disguised by looking blood fresh and newly killed . So all our food supply is affected by mans pollution. It is very important to go organic therefore.