Julian Paolo Biyo Jason Andrei TemeloI-RubyPhilippine Science High School Western Visayas Campus Investigatory Project
TITLE: Effect of the Different Types of Substrates on theBiodegradability of SM Plastic Bags I.
Background of the Study
Official figures show that plastics make up around 25% of thegarbage that metro manila churns out, while an independent surveyconducted by Ecowaste Coalition and Greenpeace on the compositionof discards on manila bay in 2006 found that 51% were plastic bags,19% sachets and junk food wrappers, 5% Styrofoam, 1% hard plastics,10% rubber, 13% biodegradable wastes (Cayetano, 2008;www.senatorpiacayetano.com/psc/pressreleasedetails.php?recordID=175)Biodegradable plastics are degradable plastics on which thedegradation results from the action of naturally occurring micro-organisms such as bacteria, fungi , and algae (email@example.com). These plastics are broken down into water, carbon dioxide, methaneand biomass primarily through enzymatic action on microorganisms(Azios, 2007www.csmonitor.com/2007/1219/p16s01 -sten.html).Biodegradable will fully disintegrate in six months or less. It turns intopowder and blends with the soil after a few months (Demetillo, 2008www.smprime.com/News.php?BlurbID=1113).Many biodegradable plastics will decompose in industrial plants,backyard compost piles, or open environments. The inherentbiodegradability of plastics depend on several environmental factorssuch as moisture, temperature, surface area, and the manufacturingmethod of the finished product. (Nolan-ITU Pty Ltd, 2002www.environment.gov.au/settlement/publications/waste/deg) [pic][pic][pic][pic][pic]
Although some brands claim to be biodegradable in open air andsaltwater, virtually no decomposition occurs within a closed landfillthat has been capped, preventing air circulation. (Azios, 2007www.csmonitor.com/2007/1219/p16s01 -sten.html) The SM mall chain has started shifting biodegradable plasticbags for its supermarkets and department stores (Cayetano, 2008). The use of biodegradable plastics help lessen the burden of the ever-growing garbage problem in the Philippines and in the whole world II.
Problem of the Study
This study was conducted to answer the following problem:Will exposing the SM plastic bags to different substrates such ascompost soil, loam soil, tap water, and seawater over a period of timeaffect its biodegradability? III.
Hypothesis of the Study
If SM plastic bags will be placed in different substrates over aperiod of time, then its biodegradability will be affected. IV.
Objectives of the Study
To determine the effect of different substrates on the biodegradabilityof SM plastic bags. B.
To expose SM plastic bags to different substrates such as compost soil,loam soil, seawater and tap water for a duration of several months. 2.
To measure the weight of the plastic bags (grams) before and afterdifferent exposure periods to the substrates.3.To compare the percent weight loss of the SM plastic bags exposed todifferent substrates after a period of time. [pic]
V.Design of the Study
V.Design of the Study
A.VariablesA1. Independent variables/ manipulated variable: substrate 1.
Compost soil2.Loam soil3.Seawater4.Tap waterA2. Dependent variable/ responding variable: biodegradability (percentweight loss)B.Materials •
6, 1-litre glass jars
6, 7”x9” aluminium trays
12 pcs. 3”x4” SM plastic bags
500g loam soil
500g compost soil
500mL tap water
Weighing scaleC.ProceduresWe cut the SM plastic bags into 3”x4”sizes strips. We labelled theplastic strips into C1, C2, C3 for compost soil, L1, L2, L3 for loamsoil, S1, S2, S3 for seawater, and T1, T2, T3 for tap watertreatments. We then determined the initial weights of the plasticstrips in grams using the analytical balance. The initial weights (W1)of the plastic strips were then recorded in...