The Effects of Dish Detergent on Algae. Luke J. Barrante PJAS Central Catholic High School

Transcription

1 The Effects of Dish Detergent on Algae Luke J. Barrante PJAS Central Catholic High School

2 Eutrophication Enrichment of aquatic ecosystems with nutrients Can occur as lakes age through geological time First recognized as a pollution problem in the mid-20th century

3 Chlamydomonas reinhardtii Have two flagella Typically 10-30um wide Eyespot helps them gravitate toward light Found in calm water, damp soil, and snow Contains only one chloroplast Model species- research/bio indicators

4 Sodium Tripolyphosphate (STPP) dish/laundry detergent additive in a powdered form Accounts for over 50% of the dish phosphate effluent from our wastewater facilities Cannot be removed by secondary water treatment Accounts for up to 12% of manmade phosphorus in bodies of water

5 The EPA on STPP In 2008, the EPA stated that sodium tripolyphosphate causes eutrophication. It was suggested that phosphate be reduced in detergents. In 2010, Pennsylvania banned detergent formulas containing more than 0.05% phosphate. In hard water areas, glasses turn cloudy, grease builds up, etc.

6 Purpose The purpose of this experiment is to study the effects of sodium tripolyphosphate on Chlamydomonas population growth.

7 Hypothesis Experimental (single, formal hypothesis): sodium tripolyphosphate and dish detergent will individually and synergistically alter algal growth. Null (necessary only for statistical analyses): sodium tripolyphosphate and dish detergent will not individually or synergistically alter algal growth.

8 Materials 1. Chlamydomonas reinhardtii 2. Soil water (Carolina) 3. Spring water (Giant Eagle brand) 4. Phosphate-free dish detergent (Reeva) 5. Sodium tripolyphosphate (SoapGoods) 6. Spectrophotometer (Carolina) μl and μl micropipettes 8. Test tubes and rack 9. Lamp 10. Small box

9 Procedure 1. Four test tubes each were filled with the following concentrations. Test Tube Chlamy 2mL 2mL 2mL 2mL 2mL 2mL 2mL 2mL 2mL Soil Water 1mL 1mL 1mL 1mL 1mL 1mL 1mL 1mL 1mL Spring Water 2mL 1.995mL 1.95mL 1.995mL 1.99mL 1.945mL 1.95mL 1.945mL 1.9mL Phosphate 0mL 0.005mL 0.05mL 0mL 0.005mL 0.05mL 0mL 0.005mL 0.05mL Dish Detergent 0mL 0mL 0mL 0.005mL 0.005mL 0.005mL 0.05mL 0.05mL 0.05mL Phosphate Dish Detergent 0%, 0% 0.01%, 0% 0.1%, 0% 0%, 0.01% 0.01%, 0.01% 0.1%, 0.01% 0.1% 0%, 0.1%.01%, 0.1% 0.1%, 0.1%

10 Procedure 2. Absorbance readings of the tubes were taken at 430 nm. 3. The tube rack was placed in an open box. 4. Box was positioned directly under a lamp in a windowless room. 5. Absorbance readings were taken at 430 nm on selected days. 6. Change in absorbance from initial readings were recorded.

11 Delta absorbance at 430 nm X4 0.3 Dish Detergent and Phosphate Effects on Algae Growth low detergent control low phosphate Days after initial reading 0% P, 0% D 0.01% P, 0% D 0.1% P, 0% D 0% P, 0.01% D 0.01% P, 0.01% D 0.1% P, 0.01% 0% P, 0.1% D 0.01% P, 0.1% D 0.1% P, 0.1% D low phosphate high detergent high phosphate low phosphate low detergent high phosphate low detergent high detergent high phosphate high detergent

12 ANOVA Analysis ANalysis Of VAriance Single factor- the comparison of means Two factor- a comparison to test interaction (synergy) between two independent variables If the P-value is > 0.05, ACCEPT the null hypothesis. If the P-value is < 0.05, REJECT the null hypothesis.

13 ANOVA Analysis P-values Day 7 Day 13 phosphate (single-factor) dish detergent (single-factor) interaction (two-factor)

14 Dennett's Test Analysis a multiple comparison procedure that compares each of a number of treatments with a single control. test gives a t-value which is compared to the ANOVA s t-critical value; variance is significant if t-value is greater than t-crit Variance Day 7 Day 13 Low Phosphate insignificant insignificant High Phosphate significant significant Low Detergent insignificant insignificant High Detergent significant significant

15 Conclusion The null hypothesis is REJECTED- phosphate and detergent had significant individual and synergistic effects on algal growth. Further data in the Dennett's test analysis suggests that in large quantities, these variables significantly harmed algal populations and in small amounts, had little to no significant effect. These results do not support the EPA s claim that detergent phosphate produces larger populations of algae.

16 Limitations Only one species of algae was used. Culture of Chlamydomonas could have been unhealthy. The testing period only spanned 13 days. Only four replicates were used. Only nine concentrations were tested. Test does not explain whether or not algae actually harms aquatic ecosystems. Not all ponds are the same. Extensions Test more than one species of algae, such as Euglena. Test multiple cultures of Chlamydomonas. Extend the testing period to longer than 13 days. Use more than four replicates. Test a wider variety of concentrations of pollutants. Perform a follow-up study that determines the effects of excess algae on aquatic ecosystems. Test with conditions of multiple ponds.

17 References