EFFECTS OF CONTAMINANTS ON PLANTS
Pollution may be any solid, liquid, or gas added to air, water or soil, that threatens the health, survival, or activities of living organisms. These unwanted or harmful additions to the environment are known as pollutants. Most pollutants are unintentional by-products of human activities, such as industrial processes or chemicals used in agriculture. Pollution can also take the form of heat, noise or radiation. Examples of common air and water pollutants include pesticides, fertilizers, herbicides, sediment, dust, mercury, lead, radon and cigarette smoke.
Pollutants can be further divided into two categories: degradable andnondegradable. Degradable pollutants can be decomposed to harmless compounds by natural, physical, chemical, and biological processes. Biodegradable pollutants are those that can be degraded by living organisms. Unfortunately, many of these pollutants still take decades or longer to degrade. Non-degradable pollutants, such as lead and mercury, can only be removed from the environment by costly technical processes.
Petrochemicals are common biodegradable pollutants, although they can be quite toxic to life. These include crude oil, gasoline, natural gas and kerosene. Aside from major shipping and pumping spills, people often do not properly dispose of their motor oil and other petrochemicals (paint thinner, etc.). Many pour it down the drain or in storm sewers rather than taking it to a facility that will dispose of the substance properly. Furthermore, most impervious surfaces (parking lots and roads, for example), where our vehicles drip petrochemicals, drain directly into storm drains, which drain directly into streams like the Ottawa River, rather than to a water treatment plant as most people assume. Thus, petrochemical contamination in urban environments is widespread.
While non-degradable pollutants such as lead and mercury contaminate area of intense industrialization, perhaps more sinister is the salinization of soils due to irrigation of our food crops. All water contains some concentration of dissolved salts (even rain water), and soils used for crops typically regulate the amount of salt through plant uptake and flushing. However, in some soils where irrigation is predominant, the concentration of salts can be much higher than normally found. As the water evaporates after application, the salts are left on the surface of the soil, eventually leading to a decrease in soil productivity. For example, in the California Central Valley approximately 4.5 million acres of irrigated cropland (half the total) is affected by salinization. Considering that 8% of the nation’s total agricultural output comes from this region (and many of our winter or specialty crops), it is worthwhile to investigate how our choices at the supermarket contribute to these processes.
This lab is a controlled experiment where radishes are grown to determine if there are growth differences resulting from those treatments of pollutants.
WATER QUALITY: PHYSICAL, CHEMICAL, AND NUTRIENT CHARACTERISTICS
The Great Lakes hold about 20% of the entire earth’s surface freshwater. Lake Erie, streams, rivers, and other lakes are the primary sources for irrigation, industry, and domestic use in most of Ohio. These water bodies also provide habitat for fish and wildlife, and so, are important to tourists, hunters and fishermen. The quality of these surface waters clearly affects their suitability for use. Water that has been polluted often is not fit for either wildlife habitat, or for human and/or animal consumption. Hence, water quality has direct impacts upon the local economy, as well as the health and survival of people and wildlife. For example, Lake Erie alone generates approximately $2 billion for the State of Ohio in tourism.
What is water quality?
Water quality is an ambiguous concept that refers to the general “health” of the water (defined largely in human terms). However, this concept has a large number of both qualitative and quantitative characteristics.
Physical and chemical parameters
Some of the more common physical and chemical attributes of water quality that affect biota are largely defined by abiotic factors such as pH, dissolved oxygen, electrical conductivity, and turbidity. Each of these factors is strongly influenced by the amount of nutrients in the water, which is derived by the amount of nitrogen and phosphorus molecules available. When these molecules are in great abundance, as they are due to human activities, a process called eutrophication can occur.
Eutrophication
Eutrophication is the process of enriching a water body with nutrients. Nutrients naturally enter water from the atmosphere and with sediments from runoff. Sediments originate from soil erosion, which is greatly increased by farming, overgrazing and deforestation.
The most common nutrients contributing to eutrophication are phosphates, ammonia, and nitrates which stimulate the rapid growth of phytoplankton. Nutrients further increase the turbidity of the water, which shades the submerged benthic plants and modify the structure of the ecosystem.
Cultural eutrophication results from human activities, which usually accelerate the natural process. This is the direct result of nutrient inputs to waterways. This lab will acquaint you with some standard water quality tests that are commonly used to assess water supplies. This lab will use water samples from across the Ottawa River watershed, beginning at a State Nature Preserve, in the suburbs, and then on campus.
COLIFORM BACTERIA IN SURFACE WATERS
Many organisms, including humans, have symbiotic bacteria in their guts that aid digestion. Symbiosis is an intimate relationship between different organisms in which both the host organism, e.g. the human, and the symbiote, e.g. bacteria, benefit from each other. In this case, the bacterium gets a favorable environment and food source in the intestines of a human. In return, these bacteria improve the digestibility of food through a host of enzymatic processes.
A subset of this group of bacteria is known collectively as fecal coliforms, which includes the well-known E. coli, some strains of which are necessary for human health, and some which are pathogenic and can make you very sick. Although the beneficial strains of this bacteria aid human digestion, finding these bacteria in waterways serves as a warning for the potential spread of disease because they can indicate human or animal feces. Therefore, coliform bacteria are used in water quality testing as indicators of other pathogenic bacteria that commonly are found associated with coliforms, e.g., Salmonella, Shigella, Yersinia, Klebsiella and certain strains of E. coli.
How do Coliforms get there? What is required is any type of mammal or bird producing excrement. This could be as simple as a duck floating on a pond or a human flushing the toilet. These single events, however, will not produce enough bacteria to be detected. What is required is some concentrated amount of waste entering the environment.
For example, Ohio does not issue Clean Water Act permits specifically for concentrated livestock operations. Ohio is the number one egg producing state, and what happens with the excrement of 30 million chickens? For the most part, these wastes are applied to agricultural fields as fertilizer, which can be extremely beneficial. What is problematic is that the state has no local control over factory farm operations and allows these farms to dump manure offsite without revealing the location under the Ohio Trade Secrecy Act. Therefore, Ohio has no control over the timing of application, the concentration of application or the distance to any waterway.
Livestock operations are not all to blame. In many urban areas, storm water sewers are combined with waste water sewers in what is known as a Combined Sewer. During large rain events, the amount of water in the Combined Sewer exceeds the capacity of the waste water channel and overflow directly into streams. This is unlawful under the Clean Water Act and municipalities (including Toledo) are now required to remove these types of systems. Even in low density rural areas, faulty septic systems release coliform into waterways.
This lab will acquaint you with a standard coliform test that is commonly used to assess water supplies. This lab will use water samples from across the Ottawa River watershed, beginning at a State Nature Preserve, in the suburbs, and then on campus.
The Lab Report
Selecting a Topic
The lab report is a semester long project. You will choose one of the following lab topics to write your report:
1. Plant Contamination Lab
2. Water Quality Lab
3. Coliform Analysis
Purpose
The purpose of the lab report is to expand on a topic covered in class and present the results in a formal report. While the lab manual and short lectures provide some background information, but the lab report requires you to conduct a brief literature review. This means that you should not repeat what is said in the lab manual, and should use different sources.
General Instructions for the Lab Report
• Lab reports must be typed (double-spaced) and will be evaluated for proper spelling, grammar, punctuation, etc.
• If you have questions, discuss them with the instructor BEFORE they are to be handed in, preferably during office hours.
• Draft sections will be due as scheduled, graded and returned to you for improvement before being compiled into the final report (see schedule).
Report format
1) Title and byline: Make your title concise and informative; include your name, date and lab section.
2) Introduction: The Introduction will include two paragraphs, a paragraph that introduces the topic you are investigating, and a paragraph that introduces what you specifically propose to investigate.
The first paragraph (introductory paragraph):
o Your first sentence (topic sentence) of the introductory paragraph should introduce the ‘big picture concept’ what you are addressing in that paragraph.
? “Nitrous oxide pollution is a threat to human health.”
o Consequent sentences provide information that describes the relevance of the topic sentence. The supporting sentences will come from a minimum of 3 resources, one of which is from a peer reviewed journal and recent (2005 or later).
o To cite references, list the author’s last name and year of the publication at the end of the sentence in which you used information from that source.
? “Nitrous oxides will not cause acute illness at low concentrations, as it is a secondary pollutant (Smith 2005), but becomes toxic in combination…”
• For two authors: Smith & Smith 2005. For more than two authors: Smith et al. 2005.
o Conclude the paragraph with a rationale for why you are interested in this topic, which also introduces the next paragraph (investigatory).
The second paragraph (investigatory paragraph):
o Your first sentence introduces your scientific question.
? “To investigate the amount of nitrous oxides on the Toledo region, I compared air samples west and east of town.”
o State your hypothesis.
? “I hypothesize that air samples west of town will be lower in nitrous oxides than east of town.”
o Define the X (predictor) and Y (response) variables.
? “My predictor variable is‘Location’. My response variable is ‘Nitrous Oxide Level.’”
o Provide a rationale for why you think your hypothesis will be supported.
? “Large cities emit great amounts of nitrous oxides from combustion, and the prevailing winds in the Toledo region blow from west to east.”
3) Methods: The methods should provide enough detailed information that anyone can replicate your exact experiment even if they have never done it before.
o Describe how the data were collected. Keep the description specific to the data you are using in your analysis.
? Include description of the predictor and response variables, and the number of replicates you included in each treatment.
o Describe the type of lab analysis (technique and equipment) used to quantify your data.
? “I used….”
o Describe your calculations and statistics. Identify the software package used and the type of analysis conducted.
? “To compare means and variances, I used Excel and GraphPadto perform a T-test.”
4) Results: The results describe the answer to your question, which is demonstrated through a table, graph and a statistic.
o Make a table that lists the raw data collected (sites, treatments, observations, etc.)
o Make a figure of what you compared with your predictor variable(s) and the response variable, and report the p-value of the statistical test.
o Write a sentence that states the numerical values and variances (error) of each of your response variables.
o A sentence that states whether your statistical testsupported or rejected your hypothesis.
? “The p value in my test was higher than 0.05 (p=0.68). Therefore, my hypothesis that […] was rejected.”
5) Discussion: The discussion reiterates your question and your finding. If the hypothesis is not supported, you should discuss why you think the answer was different that you hypothesized.
o Begin by reviewing the purpose, data and original question.
o Did the results support or refute your original hypothesis? Why or why not?
o What implications are suggested? Avoid the concept of “proof.” Hypotheses may “fail to be rejected” or may be supported, but are not proven. Results “indicate” or “demonstrate” a point, but they do not prove a point.
o On which assumptions did you base your conclusions and what shortcomings do they present? What further research could be done?
o Note: Error means “variance”. You are to assume that all data were collected properly. Therefore, you are required to avoid the trap of assigning “human error” as a reason you hypothesis was unsupported. This is not an acceptable reason for variance (error).
6) Conclusion: The conclusion discusses the fundamental points that were demonstrated, and is a brief summary reiteration of your Discussion. Organize this section around the main points from your introduction (rationale for study, etc.) and then expand on those points using your results.
7) References: At least three sources, including one primary source, should be cited in your lab report. Give the full citation of literature cited in your report using MLA formatting (http://owl.english.purdue.edu/owl/resource/557/01/).
Report Grading
Note: The report is due in portions
Draft Introduction & Literature cited 25 pts
Draft Methods 25 pts
Draft Results, Discussion & Conclusions 25 pts
Final report 75 pts
Total value 150 pts
Report Citations
For your lab reports you are required to use and cite at least two primary sources.
What is a Primary Source?
• Primary sources present original thought, reports on discoveries, or share new information.
• Primary sources are original materials on which other research is based
• They are usually the first formal appearance of results in the print or electronic literature (for example, the first publication of the results of scientific investigations is a primary source.)
• They present information in its original form, neither interpreted nor condensed nor evaluated by other writers.
Examples of Primary Sources:
• Scientific journal articles reporting experimental research results
• Technical reports
• Dissertations or theses
• Government documents
For example, a news article or web story may report on the findings from a primary source, but the news article is not a primary source.
Wikipedia, for our purposes, is a fantastic place to begin your research and better understand the topic, but it is not a primary source. However, many of the links found at the bottom of the Wiki article ARE primary sources (some are not), and you may use those primary sources to cite your information. Your Instructor will help you understand the difference between the two in class.
Other Places to Look for Primary Sources:
• Google Scholar: http://scholar.google.com/
• OhioLINK electronic journal finder is good for deciding which journals are appropriate to search and it provides links directly to the journals. http://www.ohiolink.edu/resources/ejournals.php
• JSTOR has full text scientific journal articles http://www.jstor.org/
• UT Library page: http://www.utoledo.edu/library/
The Lab Report
Selecting a Topic
The lab report is a semester long project. You will choose one of the following lab topics to write your report:
1. Plant Contamination Lab
2. Water Quality Lab
3. Coliform Analysis
Purpose
The purpose of the lab report is to expand on a topic covered in class and present the results in a formal report. While the lab manual and short lectures provide some background information, but the lab report requires you to conduct a brief literature review. This means that you should not repeat what is said in the lab manual, and should use different sources.
General Instructions for the Lab Report
• Lab reports must be typed (double-spaced) and will be evaluated for proper spelling, grammar, punctuation, etc.
• If you have questions, discuss them with the instructor BEFORE they are to be handed in, preferably during office hours.
• Draft sections will be due as scheduled, graded and returned to you for improvement before being compiled into the final report (see schedule).
Report format
1) Title and byline: Make your title concise and informative; include your name, date and lab section.
2) Introduction: The Introduction will include two paragraphs, a paragraph that introduces the topic you are investigating, and a paragraph that introduces what you specifically propose to investigate.
The first paragraph (introductory paragraph):
o Your first sentence (topic sentence) of the introductory paragraph should introduce the ‘big picture concept’ what you are addressing in that paragraph.
? “Nitrous oxide pollution is a threat to human health.”
o Consequent sentences provide information that describes the relevance of the topic sentence. The supporting sentences will come from a minimum of 3 resources, one of which is from a peer reviewed journal and recent (2005 or later).
o To cite references, list the author’s last name and year of the publication at the end of the sentence in which you used information from that source.
? “Nitrous oxides will not cause acute illness at low concentrations, as it is a secondary pollutant (Smith 2005), but becomes toxic in combination…”
• For two authors: Smith & Smith 2005. For more than two authors: Smith et al. 2005.
o Conclude the paragraph with a rationale for why you are interested in this topic, which also introduces the next paragraph (investigatory).
The second paragraph (investigatory paragraph):
o Your first sentence introduces your scientific question.
? “To investigate the amount of nitrous oxides on the Toledo region, I compared air samples west and east of town.”
o State your hypothesis.
? “I hypothesize that air samples west of town will be lower in nitrous oxides than east of town.”
o Define the X (predictor) and Y (response) variables.
? “My predictor variable is‘Location’. My response variable is ‘Nitrous Oxide Level.’”
o Provide a rationale for why you think your hypothesis will be supported.
? “Large cities emit great amounts of nitrous oxides from combustion, and the prevailing winds in the Toledo region blow from west to east.”
3) Methods: The methods should provide enough detailed information that anyone can replicate your exact experiment even if they have never done it before.
o Describe how the data were collected. Keep the description specific to the data you are using in your analysis.
? Include description of the predictor and response variables, and the number of replicates you included in each treatment.
o Describe the type of lab analysis (technique and equipment) used to quantify your data.
? “I used….”
o Describe your calculations and statistics. Identify the software package used and the type of analysis conducted.
? “To compare means and variances, I used Excel and GraphPadto perform a T-test.”
4) Results: The results describe the answer to your question, which is demonstrated through a table, graph and a statistic.
o Make a table that lists the raw data collected (sites, treatments, observations, etc.)
o Make a figure of what you compared with your predictor variable(s) and the response variable, and report the p-value of the statistical test.
o Write a sentence that states the numerical values and variances (error) of each of your response variables.
o A sentence that states whether your statistical testsupported or rejected your hypothesis.
? “The p value in my test was higher than 0.05 (p=0.68). Therefore, my hypothesis that […] was rejected.”
5) Discussion: The discussion reiterates your question and your finding. If the hypothesis is not supported, you should discuss why you think the answer was different that you hypothesized.
o Begin by reviewing the purpose, data and original question.
o Did the results support or refute your original hypothesis? Why or why not?
o What implications are suggested? Avoid the concept of “proof.” Hypotheses may “fail to be rejected” or may be supported, but are not proven. Results “indicate” or “demonstrate” a point, but they do not prove a point.
o On which assumptions did you base your conclusions and what shortcomings do they present? What further research could be done?
o Note: Error means “variance”. You are to assume that all data were collected properly. Therefore, you are required to avoid the trap of assigning “human error” as a reason you hypothesis was unsupported. This is not an acceptable reason for variance (error).
6) Conclusion: The conclusion discusses the fundamental points that were demonstrated, and is a brief summary reiteration of your Discussion. Organize this section around the main points from your introduction (rationale for study, etc.) and then expand on those points using your results.
7) References: At least three sources, including one primary source, should be cited in your lab report. Give the full citation of literature cited in your report using MLA formatting (http://owl.english.purdue.edu/owl/resource/557/01/).
Report Grading
Note: The report is due in portions
Draft Introduction & Literature cited 25 pts
Draft Methods 25 pts
Draft Results, Discussion & Conclusions 25 pts
Final report 75 pts
Total value 150 pts
Report Citations
For your lab reports you are required to use and cite at least two primary sources.
What is a Primary Source?
• Primary sources present original thought, reports on discoveries, or share new information.
• Primary sources are original materials on which other research is based
• They are usually the first formal appearance of results in the print or electronic literature (for example, the first publication of the results of scientific investigations is a primary source.)
• They present information in its original form, neither interpreted nor condensed nor evaluated by other writers.
Examples of Primary Sources:
• Scientific journal articles reporting experimental research results
• Technical reports
• Dissertations or theses
• Government documents
For example, a news article or web story may report on the findings from a primary source, but the news article is not a primary source.
Wikipedia, for our purposes, is a fantastic place to begin your research and better understand the topic, but it is not a primary source. However, many of the links found at the bottom of the Wiki article ARE primary sources (some are not), and you may use those primary sources to cite your information. Your Instructor will help you understand the difference between the two in class.
Other Places to Look for Primary Sources:
• Google Scholar: http://scholar.google.com/
• OhioLINK electronic journal finder is good for deciding which journals are appropriate to search and it provides links directly to the journals. http://www.ohiolink.edu/resources/ejournals.php
• JSTOR has full text scientific journal articles http://www.jstor.org/
• UT Library page: http://www.utoledo.edu/library/
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