83. Solving a chemistry problem

29. The MAC for phenol (PhOH) in natural water is 0.001000 mg/dm3. To determine phenols in water from the production of formaldehyde resins, 100.00 cm3 of water was diluted to 500.00 cm3, passed through a column with activated carbon to remove impurities that interfere with the determination, then phenols were extracted in an acidic medium, 4-aminoantipyrine was added to the extract, with which phenols at pH = 10.00 form colored compounds with an absorption maximum at λ = 460 nm. The optical density of the test solution is 0.160. The standard solution was prepared by dissolving 1.00 cm3 of a solution with T (phenol) = 1.000 μg/ml in a measuring flask with a capacity of 500.00 cm3. The optical density of the standard solution, carried through all stages of analysis, was 0.175. What is the concentration of phenol in the wastewater? Can it be released into a natural reservoir?