Q. Is paraquat an endocrine disruptor?

A. An endocrine disruptor is a synthetic chemical that when absorbed into the body either mimics or blocks hormones and disrupts the body's normal functions. Like all crop protection products, paraquat has been subjected to a full regulatory toxicological evaluation, including the required mammalian studies. Such studies allow for the examination of toxicological affects following repeated exposure of a range of species to paraquat. Studies such as these evaluate the ability of materials to cause significant adverse effects through endocrine disruption and no evidence linking endocrine disruption to paraquat has been found.

In its report, “Towards the establishment of a priority list of substances for further evaluation of their role in endocrine disruption” for the European Commission DG Environment, BKH Consulting Engineers lists paraquat as a group III substance, which means there is no scientific basis for inclusion on the endocrine disruptor list. In reaching this conclusion, BKH cites two mammal in vivo studies, which are negative for endocrine disruption.

Paraquat appears on the World Wildlife Fund’s (WWF) list of substances of 'reproductive and /or endocrine effects'. However the criteria used to determine this placement are unclear. WWF’s data were considered by BKH in developing its recommendation.