Essay on Plant Growth

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Chemical pollution can have serious ramifications on the impact of plant growth. This sample environmental science essay explores a study that was conducted that shows chemical pollutants and their impact on plant growth.

Summary of the plant growth research and findings

The impact of chemical pollution on the environment has been an ever present topic due to the potential negative effects on plants and other living organisms that might be exposed to these chemicals. The study's thesis statement claims fragrances are a primary cause of reduced plant growth due to harmful chemicals released into the ground and water.

Fragrances, an active chemical found in most discarded products, are believed to cause a negative effect on the growth of plants. A study was conducted where the growth of 24 beans was observed using common household liquids as a watering solution. The four solutions used in this study were:

1. Shampoo
2. Vinegar
3. Bleach
4. Water

In the study, the beans would be separated into groups where some would exclusively be watered with one solution and others having some fragrance being applied to them. The study showed common household products can have harmful abilities on plants if substantial amounts are used. Researchers also noticed that diffusion of particles in the air limits the damage the fragrance had on the plant.

Understanding the chemical make-up of household fragrances

Modern fragrances originated in the late 19th century and have been a major part of cosmetics and household chemicals since that time. This category consists of four primary products:

1. Essential oils
2. Aroma compounds
3. Fixatives
4. Solvents

Fragrance is harmless in small amounts, but due to the growing population in the United States, small amounts of have been found in human fat, milk, and waterways. In recent decades, pharmaceuticals, personal care products, and other household chemicals have received much scrutiny due to their adverse impact on the environment. Recent U.S. environmental policies have improved the ingredient list. However, most of these chemicals have fragrances in them.

Identifying harmful effects chemicals have to plant growth

The issue at hand has been for many is figuring out if, after disposing of these products, these chemical compounds pose an eco-toxic threat to plants and other living organisms. Researchers believe the chemicals being disposed of, more often than not the method being through gray wastewater causes some sort of change in the growth of plants. The excretion of these chemicals usually occurs in low concentrations in the environment and is unlikely to cause any acute toxicity (Jemba 2006).

Shampoo is a very commonly used household care product. Shampoo is used daily and is washed down the drain. Shampoo removes oil and dirt from scalps to keep hair clean. Fragrance is added to give it a pleasant smell. However, the harsh chemicals found in shampoo have been linked to the cause of global warming and have an effect on the water systems, which go on to affect plants.

The many chemicals that are poured down the drain could potentially contaminate and pollute water. Because of common household items, such as the many kinds of soaps, fish are found dead in rivers because the chemicals that run off. In previous years, there have been reports on the contamination of aquifers. The water that people drink, come from aquifers and there is a chance there are chemicals because of what is drained down or flushed in the toilet.

Common compounds found in household chemicals

Most compounds used in households on a daily basis once broken down are quite harmless. The top compound ingredients most commonly found are water are:

1. Glycerin
2. Propylene Glycol
3. Fragrance
4. Sodium Chloride
5. Tetrasodium EDTA
6. Sorbitol
7. Citric Acid
8. Sodium Lauryl Sulfate
9. Phenoxyethanol
10. Titanium Dioxide
11. Tocopheryl Acetate
12. Flavor
13. Stearic Acid
14. Sodium Hydroxide
15. Methylparaben
16. Propylparaben
17. Alcohol
18. Cocamidopropyl Betaine
19. Cyclopentasiloxane

In significant quantities, some of these could be problematic for an organism the size of a human, but the possibility that even trace amounts could have debilitative or even catastrophic effects on plants, particularly in the germination stage. Some of the most common and least hazardous substances were water and glycerin which have an EWG rating of 0.

Glycerin is used for several cooking products, one common example is jelly. The glycerin is what causes the jelly to firm up once dissolved in water. Glycerin is also used in several non-food products ranging from shampoo to biodiesel fuel, to body lotions, to dog toys. This chemical is a very common substance but is acceptably safe as well.

One notable and surprising substance was propylene glycol with an EWG rating of 3. This product is used in antifreeze for cars. Propylene glycol is extremely toxic if consumed by humans and animals and seems as though this chemical should have had a much higher rating to account for its extreme danger to living things.

Products used in the study to determine effect of fragrances

All of our tested products were relatively low on the EWG scale. Fragrance came in at EWG 7, but most of the others were rated less than 5. These results were not expected. It was assumed that most of the products that we use on a daily basis were much more toxic. The research group focused on fragrance, because of its relatively high EWG rating.

The primary research question is: What are the effects of fragrances on plants? It is believed that plants are affected by household chemicals, because of the harsh fragrances that could harm or kill them. However, there are two sides to this argument.

Others believe that shampoo, vinegar, and bleach do not affect the growth of plants because many shampoos, vinegar, and fragrances originate from plants. Vinegar is most notably known for its uses in cooking, cleaning, and gardening. Fragrance is most commonly used in perfume to give it an aromatic smell but can be found in other products for the same purpose.

Overuse of fragrant plants and decrease in growth numbers

Some of the issues caused by fragrance are the gradual decline of certain species such as Sandalwood and Agarwood, due to the high demand of fragrances containing the materials. The overuse of fragrance can cause side effects such as nausea, asthma attacks, headaches and allergic reactions. These effects are limited in occurrence, though, and are most often associated with extremely high concentrations or vulnerabilities of the person exposed.

The general concern by interest groups is the harmful impact of chemicals from household items on the environment. Water is an extremely important medium for transporting organic compounds in the environment (Jjemba, 2004). Wastewaters are the main transporting system for most of these chemicals. As such this would affect the rates at which the environment is absorbing household compounds. Scientists have found this to be the case of marine pollution and decline of oceanic bacterias.

Previous studies have been conducted to test the effects on plants, more notably on how natural freshwater Algal Assemblages are affected by pharmaceutical and personal care products (PPCP’s). In the study, three PPCP’s were individually tested using laboratory dilution bioassays n Olathe, KS Waste Water Treatment Plant (Wilson, Smith, Dinoyelles, Larive, 2003).

• Ciprofloxacin (an antibiotic)
• Triclosan (an antimicrobial agent)
• Tergitol NP 10 (a surfactant)

Initial data showed no real treatment effects during the exponential phase but significant changes were observed in the results. The three compounds were found to have caused a shift in the structure of the suspended and attached algae. The results pointed towards the use of the three PPCP’s having an influence on both the structure and the function of algal communities near Wastewater Treatment Plants (Wilson, Smith, Dinoyelles, Larive, 2003).

Research methods used to measure declining plant growth and causes

The design of the primary research is relatively simple. The team took 24 bean seeds and water them with water containing shampoo, vinegar, and bleach. Each set of two bean seeds will be watered with the specified chemical (Shampoo, vinegar, and bleach) that contain fragrance and one with fragrance-free. There will also be 2 control plants containing regular water. This water mixture is going to be mixed precisely and dosed the same each time for consistent results.

The procedures will be as such, 8 cups will be filled with soil each of which will contain 3 beans. Then 20mL of water will be poured into each cup. Two cups will then be poured with 5mL of bleach with and without fragrance. The next two cups will be poured with 5mL of vinegar with and without fragrance. Another two cups will be poured with 3mL of shampoo with and without fragrance. The last two cups will just be poured with regular water.

This process would be repeated 3-8 times every day. The growth of the plant would then be observed and measured in centimeters. I hypothesize that the seeds being watered with the chemical containing fragrance will grow slower and eventually perish.

Results and conclusion

The final results of the experiment were limited, and growth in control. The other materials were placed in each cup killed the seeds, proving that certain materials that enter our water have the ability to harm plants. Humans should think before using extensive amounts of products such as bleach, vinegar, and shampoo, all of which can enter the water system and destroy the environment. This experiment also displays how the process of diffusion of particles in the air limits the damage the perfume did to the plant.

If this experiment was conducted a second time, researchers would have taken the amount of added products, such as bleach, and subtracted it from the total amount of water a plant receives each day. For example, the team would have subtracted the five mL of bleach from the twenty mL of water, so each day; the plant would receive five mL of bleach and fifteen mL of water. Hopefully, this improvement would prevent over watering certain plants.

References

Brittan A. Wilson, Val H. Smith, Frank Denoyelles, Cynthia K. Larive 2003. Effects of Three Pharmaceutical and Personal Care Products on Natural Freshwater Algal Assemblages. American Chemical Society 37, 1713-1719

Christian G. Daughton and Thomas A. Ternes 1999. Pharmaceuticals and Personal Care Products in the Environment: Agents of Subtle Change? Environmental Health Perspectives 907-938

Patrick K. Jjemba 2004. Environmental Microbiology: Principals and Applications. Science Publishers

Patrick K. Jjemba 2006. Excretion and ecotoxicity of pharmaceutical and personal care products in the environment. Ecotoxicology and Environmental Safety 63, 113-130