1. estrogenic properties (29 30). Sixth the gull embryos and chicks from Lake
2. response is quantifiable. Finally the assay Ontario showed the development of
3. for vitellogenin can be performed relative- oviducts and ovarylike gonads. Laboratory
4. ly easily and inexpensively especially com- studies have since shown that estrogenic
5. pared to the exorbitant cost of screening pesticides such as dicofol kelthane and