PREFACE

This report is the product of a comprehensive search of the
world-wide literature relating to possible effects on the public
health of using the herbicides 2,4-D, dichlobenil, endothall, and
diquat in the human environment. Sources included the following:

Computer searches: Medline, Cancerline, Toxline

Northwest Regional Health Sciences Library

University of Washington libraries: Fisheries, Biochemistry,
Science Reading Room, and Government Documents at Suzzallo
Library

National Library of Medicine

Municipality of Metropolitan Seattle Library

Friends of the Barth

Pennwalt Corporation

Thompson—Hayward Chemical Company

Chevron Chemical Company

Inter-library Loan Service of Health Sciences Library

Since most readers are not toxicologists, this report begins with
a brief explanation of the vocabulary and usual testing procedures of
environmental toxicology. Following this introductory chapter, there
are four chapters devoted to a review and analysis of research to date
on each herbicide in question. A final chapter offers general conclu-
sions about the relative risks to human health from these substances.
A brief summary and chart are included at the beginning. of the report.

Studies reporting animal assays for the detection of developmen-
tal toxicity, interference with reproduction and fertility, and car-~
cinogenesis are described in detail in a Technical Appendix. to allow
the more knowledgeable reader the Opportunity to evaluate their valid-
ity. This author's evaluation is presented after each experiment,
followed by the conclusions this, author considers justified, based on
the results reported and the adequacy of the methods used. Studies
funded by chemical manufacturers who profit from sale of the chemicals
are so identified to allow the reader to determine the possibility of

bias.

Studies reported here do not involve mixtures of chemicals unless
this is specifically stated and the controls used are defined.