Editors note. There is increasing concern about toxic chemicals in our environment. Dieldren, an organo-chlorine insecticide widely used between the 1950s’s and 70’s, is an example of the compounds called persistent organics pollutants which indeed persist in the environment and the human body. While dieldren is no longer used in Australia there are persistent organic pollutants that are. Dieldrin residues still persist in the environment, food and people. Exposure to dieldrin at high levels has been shown in both humans and animals to have numerous toxic effects including neurotoxicity and hepatocarcinogenicity. There is also substantial evidence that dieldrin has oestrogenic effects. Early life exposure to agents which are endocrine disruptors lead to disorders of the ovary, uterus, breast, and pubertal timing.

The following study reflects the importance of learning lessons from past experiences which are then applicable to potential environmental toxins today. This literature review was undertaken in 2007 by six graduate medical students at the Australian National University, supervised by Drs Colin Butler and Gillian Hall, in association with Doctors for the Environment Australia focuses on a potential link between dieldren and breast cancer.

Dieldrin is stored primarily in fatty tissues. In breast feeding women an important route of dieldrin excretion is via the breast milk, resulting in lower dieldrin levels in women who breast-feed (or express milk). This paper explores the possible link between dieldrin and breast cancer. In particular it examines whether the breast cancer-protective effect of breast-feeding, especially among younger mothers and those who feed for a prolonged time, may operate in part by decreasing a woman’s burden of dieldrin, and perhaps other carcinogenic molecules. The possible effects of dieldrin contaminated breast milk on the breast-fed infant are also discussed.

 It is hoped that this work will provide a basis to facilitate and stimulate further exploration of the possible relationship between human-produced molecules, now commonly found in both the food chain and the tissue of humans, and disease, including cancer.