2. There is a lake that is near a car manufacturing plant. The fish in the lake are showing signs of illness. You are testing to see if there is any potential contamination from the manufacturing plant. Your samples show that there is 120 mg/kg of chromium (Cr) and 300mg/kg of copper (Cu). The concentration of Al in the sample is 8000mg/kg. What are the EFs of Cr and Cu ? What are their categories of contamination? 3. You work for the depart of public health. There is a drinking water reservoir that may be contaminated with arsenic (As). The samples of the sediment in the reservoir show that there is 12mg/kg of As in the sample and 5000 mg/kg of Al. What is the EF of As and what is its category of contamination? 4. There is a nature preserve downstream of a lead (Pb) mine. If the concentration of Pb is the sediment sample taken at the preserve is 300mg/kg and the concentration of Al is 10000 , what is the EF of the sediment at the preserve? What is the level of pollution