toxicology questions

Q1 : Based on the LD50 value of dioxins in guinea pigs which was extrapolated to humans, dioxins can kill humans. Discuss what this means in toxicological terms?

 

Q2 : A company wants to do environmental remediation of contaminants. How should they determine the acceptable level of the contaminants for the remediation? What toxicological information would they need for this remediation?