From the table in Mac Berthouex and Brown $(2013)$ where the parameters for calculating acute and chronic toxicity values as function of water hardness can be found, the parameters for cadmium for the acute and chronic toxicity criteria are given as: $m_A=1\mathrm{.}0166,b_A=-3\mathrm{.}924,m_c=0\mathrm{.}7409$ and $b_c=-4\mathrm{.}719,$ where:

$C{F}_{CMC}=1\mathrm{.}136672-0\mathrm{.}41838ln($ hardness $)$

$C{F}_{CCC}=1\mathrm{.}101672-0\mathrm{.}41838ln($ hardness $)$

$q=m_{A}ln($ hardness $)+b_A$

$CMC=e^{q}C{F}_{CMC}$

$r=m_{c}ln($ hardness $)+b_c$

$CCC=e^{r}C{F}_{CCC}$

If the water hardness is $65\mathrm{.}4m\frac{g}{L}CC{O}_3,$ calculate the freshwater conversion factors?

Rounded off to $5$ significant figures:

$C{F}_{CMC}=$

Based on the given information, how many significant figures should your answer for $C{F}_{CMC}$ have?

Rounded off to $5$ significant figures:

$C{F}_{CCC}=$

Based on the given information, how many significant figures should your answer for $C{F}_{CMC}$ have?

Calculate the acute toxicity criterion.

Rounded off to $5$ significant figures:

$CMC=\frac{g}{L}$

Rounding to the correct number of significant figures for the data in the question:

$CMC=\frac{g}{L}$

If the water hardness is $65\mathrm{.}4m\frac{g}{L}CC{O}_3,$ what is the chronic toxicity criterion?

Rounded off to $5$ significant figures:

$CCC=$

$\}\frac{q}{L}$