The curve below shows the percentage of the population of aquatic species that die in response to doses of Pollutant A, a toxic substance.
Dose-response curve shows ten percent of the population died when exposed to thirty milligrams of pollutant A per kilogram of water. Twenty percent of the population died when exposed to thirty-eight milligrams of pollutant A per kilogram of water. Thirty percent of the population died when exposed to forty milligrams of pollutant A per kilogram of water. Forty percent of the population died when exposed to forty-two milligrams of pollutant A per kilogram of water. Fifty percent of the population died when exposed to forty-five milligrams of pollutant A per kilogram of water. Eighty percent of the population died when exposed to sixty milligrams of pollutant A per kilogram of water. Ninety percent of the population died when exposed to eighty milligrams of pollutant A per kilogram of water. One hundred percent of the population died when exposed to one hundred milligrams of pollutant A per kilogram of water.
A local manufacturing plant reports a spill that released pollutant A into the local watershed. Local officials must determine if the residents should be evacuated from the area. Initial groundwater samples show pollutant levels at 25 mg/kg of water. Which decision is supported by the empirical evidence provided by the dose-response curve?
Evacuation is not needed; continue groundwater monitoring.
Residents should not drink local water or use it to bathe.
Residents should be evacuated until levels increase.
Residents should only evacuate above ED50.
