Herbicides and Nitrates in Groundwater of Maryland and Childhood Cancers: A Geographic Information Systems Approach

This hypothesis-generating study explores spatial patterns of childhood cancers in Maryland and investigates their potential associations with herbicides and nitrates in groundwater. The Maryland Cancer Registry (MCR) provided data for bone and brain cancers, leukemia, and lymphoma, for ages 0–17, during the years 1992–1998. Cancer clusters and relative risks generated in the study indicate higher relative risk areas and potential clusters in several counties. Contingency table analysis indicates a potential association with several herbicides and nitrates. Cancer rates for the four types have a crude odds ratio (OR) = 1.10 (0.78–1.56) in relationship to atrazine, and an OR = 1.54 (1.14–2.07) for metolachlor. Potential association to mixtures of three compounds give an OR = 7.56 (4.16–13.73). A potential association is indicated between leukemia and nitrates, OR = 1.81 (1.35–2.42), and bone cancer with metolachlor, OR = 2.26 (0.97–5.24). These results give insight to generate a hypothesis of the potential association between exposure to these herbicides and nitrates and specific types of childhood cancer.

Key words:

• Atrazine
• Childhood Cancers
• Groundwater and Cancer
• Herbicides and Cancer
• Water Quality

Acknowledgments

We would like to thank the following institutions for providing the databases necessary for this project: the Maryland Cancer Registry, Maryland Department of Health and Mental Hygiene, the United States Geological Survey, and the Maryland Department of the Environment Water Resources Division.

Notes

¹Minimum detection levels varied for each compound (> 0.15 ug/L)

²Concentrations listed are in mg/L for nitrates and in ug/L for all other compounds