Chemical A has a 96-hr LC50 of 1 mg/L, and chemical

Question 1

Chemical A has a 96-hr LC50 of 1 mg/L, and chemical B has a 96-hr LC50 of 15 mg/L. A solution has a concentration of 1 mg/L A and 15 mg/L B. A 96-hr toxicity test of this solution produces 25 % mortality. The joint toxic action of this solution is called
A.antagonism
B.no addition
C.partial addition
D.concentration addition
E.synergism


Question 2
How does pH affect the chemical form of a toxicant in water?




Question 3

For the bioassay data, which control or reference site survival experiments yielded acceptable results for specific organisms? Select all that are correct.
A. Hyalella azteca: Lab control
B. Hyalella azteca: Ely Brook
C. Hyalella azteca: Schoolhouse Brook
D. Hyalella azteca: Ompompanoosuc River
E. Chironomus dilutus: Lab control
F. Chironomus dilutus: Ely Brook
G. Chironomus dilutus: Schoolhouse Brook
H. Chironomus dilutus: Ompompanoosuc River


Question 4

For the Hylella azteca bioassay experiments, which streams show impairment? Multiple answers may be correct.
A. Ely Brook Survival
B. Ely Brook Growth
C. Schoolhouse Brook Survival
D. Schoolhouse Brook Growth
E. Ompompanoosuc River Survival
F. Ompompanoosuc River Growth


Question 5

For the in-stream biology fish IBI surveys, which streams show impairment? Pick all that are correct.
A. Ely Brook
B. Schoolhouse Brook
C. Ompompanoosuc River


Question 6

For the in-stream aquatic RTH invertebrate surveys, which sites show impairment? Pick all that are correct.
A. Ely Brook abundance
B. Schoolhouse Brook abundance
C. Ompompanoosuc River abundance
D. Ely Brook richness
E. Schoolhouse Brook richness
F. Ompompanoosuc River richness


Question 7
Discuss how the sediment-quality parameters that you worked with in Homework 1 compare to the in-stream biology (DTH species) data and the bioassay data from this week. Do the three approaches give similar results or are there significant differences in the conclusions that you reach? Explain why or why not.



Question 8
Discuss how the surface-water quality parameters compare to the in-stream biology (fish IBI and RTH species) data from this week. Do the two approaches give similar results or are there significant differences in the conclusions that you reach? Explain why or why not.