APPENDICES

Table 1. Dissolved oxygen content and water quality relationship

DO Content (ppm O2), 20C Water Quality8-9 Clean, good water 7-11 ppm: ideal for stream fishes

including cold water fishes6.7 - 7.9 Slightly polluted4.5 - 6.6 Moderately polluted, can sustain life of warm water fishes

Below 4.5 Highly polluted0 - 2 Cannot sustain life

Molarity of Na2S2O3:

(weight of standard KIO 3)(%purity)( 6moles thiosulfate1mole iodate

)

(MW thiosulfate)(volumetitrant )

Trial Molarity1 0.012772603162 0.012811308023 0.01273413146

Average 0.01277268088DO Content:

ppmoxygen=(M thiosulfate)(vol thiosulfate)( 1moleoxygen

4moles thiosulfate)(MW oxygen)

vol sample (L)

Trial DO content (ppm O2)1 5.9243014822 5.5157289663 5.720015224

Average 5.720015224Statistical Calculations:

Our group’s data Other group’s dataTrial DO content (ppm) Trial DO content (ppm)

1 5.924301482 1 5.62 5.515728966 2 5.6284935043 5.720015224

Mean 5.720015224 Mean 5.6142Standard deviation 0.204286258 Standard deviation 0.0201479499

RSD 35.71428571 RSD 3.588748156CL 5.7200±0.5071 CL 5.6142±0.1809

Range 0.408572516 Range 0.028493504