The Phosphate Filter: Which Type of Soil? Noah Haibach Central Catholic HS 2007-2008

Phosphorus Pollution Phosphorus can cause problems in the human digestive tract. It is a growth-limiting factor. Causes overgrowth in streams and ponds; can destroy aquatic ecosystems. Comes from human waste, fertilizer, detergents, and industry point sources. Growth-limiting factor for what? You don’t have this written down.

Phosphorus Treatment Water treatment plants cannot efficiently remove phosphorus from water. Marshes can effectively remove the phosphorus. They prevent excess nutrients from causing overgrowth in bodies of water. Some marshes are constructed to treat water with high levels of phosphorus. Ex: Florida Everglades

Acceler8 Florida Everglades $8 billion project currently under way. Add 6,000 acres to State’s current 36,000 acres of treatment marshes. Lower P levels to 10-15g/L or ppb. P levels above this limit can cause imbalances in algae, plant and small animal communities. “imbalances in algae, plant and small animal communities”: can you word this better? if not, it’s probably OK.

Phosphorus Absorption 1. Incorporation into Biomass a. locked away into organic compounds by plants. 2. Retention by Soil* a. physical precipitation b. chemical absorption, where P binds to Al, Fe, or Ca. Fe must be in the fully oxidized form of iron (III) oxide. “a. bound up into organic compounds by plants”? “*Both soil-removal processes sensitive to DO level” (use “processes,” since this is a natural process, not a technique by a human? * Both soil removal techniques sensitive to DO level.

Purpose In Light of Previous Experimentation Soil removed much more P from a water sample than did cattails. Soil removed about 500 g from 1 L solution in 2 days. Chemical absorption appears to be quickest method of P removal. Soil was mixture of organic & inorganic. Which type of soil (organic or inorganic) removes the most P? Do iron oxide levels affect P removal? Could you fit a “Questions:” (maybe in red) right above your two questions, to sort of highlight that your purpose was to answer those two questions?

Hypotheses Organic soil will be richer in P, Ca, and Fe than the inorganic soil (sand). Organic soil will remove more P than sand, due to chemical absorption of P. Treatments with added iron oxide will also remove more P than treatments without.

Materials 20 clear 2-Liter pop bottles 3 3.78 bottles distilled water Anhydrous KH2PO4 Reagents for the molybdenum blue ascorbic acid method (4500-P E. method) Ocean Optics USB 2000 spectrophotometer 120 10mL test tubes w/lids 10% organic content soil Sand High-grade iron (III) oxide Graduated cylinders Automatic pipettes; micro and macro Item 2: Does 3.78 bottles mean 3.78-L bottles? You don’t need the amount of distilled water. Just write “Distilled water.” I also think you should group these items by process. First the pop bottles, then soils, then iron oxide, then water, then KHPO4, Your spectro. materials should come last.

Procedure First, gather the materials needed. Then, prepare a stock solution of 100 P mg/L (ppm). Add stock solution to each of the distilled water containers, so that they have a concentration of 1 P mg/L. Prepare cakes of soil. Mix 240mL soil/sand with 60mL water. If called for, add iron oxide so that iron oxide content is 4%. Freeze the cakes. Follow the below diagram for setup, with 4 reps for each treatment. Take 10mL samples over a period of time. Prepare the reagents for the molybdenum blue ascorbic acid method, and react the samples. This colorimetric test turns them blue. Determine the phosphorus content of samples, using a standard curve. Soil Soil & Fe Sand Sand & Fe Control 1 P ppm Soil Sand Iron Oxide 1 P ppm On slide 4, you say that g/L (i.e., micrograms per liter) is ppm. But on this slide, you say that mg/L (milligrams per liter) is ppm. Is this a discrepancy? Which is correct? 2. “so that iron oxide content is 4%” by weight or by volume or what? Should you mention this? Ask your dad or Mr. Krotec. Ok that I made your step numbers bigger? Too hard to see originally.

Experimental Corrections Too much initial P: 5 mg/L P concentration outside of range of colorimetric test: 1 cm cuvette range of 0.15 – 1.30 P mg/L Too little soil: 120mL/treatment After 1 week, very little P absorbed Corrective Steps Lower initial P to 1 mg/L Double size of soil cake Extremely Dark Samples

Data Arithmetic Standard Mean Deviation 4 replicates/treatment Day 0   Day 0 Day 2 Day 4 Control 0.95 0.00 0.91 0.03 0.72 0.09 Sand 0.96 0.02 0.86 0.06 0.73 Soil 0.98 0.04 0.49 Sand & Fe 0.22 0.08 Soil & Fe 0.92 0.68 0.26 Arithmetic Standard Mean Deviation

Chart Need to put the units and that it’s the concentration of P (or whatever). Data looks interesting!

Anova Results Day 4 Treatments P Values   Control Sand Soil Sand & Fe Soil & Fe ----------- 0.801 6.41E-03 2.76E-05 1.07E-03 ------------ 1.41E-03 5.95E-06 3.23E-04 ------------- 6.85E-05 6.64E-03 Sand w/ Fe 0.021 Soil w/ Fe Chart Observations The soil-containing samples varied from the control. The sand did not vary from the control, but the sand & Fe did vary. The sand varied from the soil. The Fe made a difference: sand varied from sand & Fe. soil varied from soil & Fe. Day 6? You only ran experiment for 4 days, right? Just FYI, I forget how this works, so I did not review your statistical data.

Conclusions Treatments with added iron oxide did remove more P than those without. Organic soil removed more P than the sand, which removed no P in comparison to the control. Sand & Iron removed more P than Organic Soil & Iron. Due to the high amount of P already present in the organic soil: Organic soil: 9 P mg/L* sand: 1 P mg/L* Dissolved oxygen levels in the soil were 4.9mg/L. DO in the control was 7mg/L; anaerobic conditions may have caused release of P from the organic soil. *Data obtained from Penn State Agricultural Analytical Services Laboratory

Accreditations Special Thanks to… Dr. Ron Ripper and Carnegie Mellon University Dr. Carrie Doonan Dr. John Stolz of Duquesne University Sources Standard Method for the Treatment of Water and Wastewater, 18th ed. (Washington D.C.: American Public Health Association, 1992), pp. 4-115 & 4-116. University of Florida, “Wastewater Treatment Wetlands: Applications and Treatment Efficiency,” http://edis.ifas.ufl.edu/SS294 Science Daily, “Everglades Phosphorus Limits On The Right Track, But More Is Needed”, http://www.sciencedaily.com/releases/2007/10/071024092417.htm

Sand Sand + Fe Org. soil Org. soil + Fe Control