Tox 3

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1) Discuss the pesticide dichlorodiphenyltrichloroethane (DDT). What was DDT initially used for, and how does it work as a pesticide? Explain the benefits of DDT, and then discuss how DDT moves through the environment.Your response should be at least 300 words in length.

2)Explain the difference between pollution and contamination. Discuss a specific environmental pollutant that has had a negative effect on the environment. How did the pollutant affect the environment? How was the pollutant introduced and transferred throughout the environment?

Your response should be at least 300 words in length.

3)A family goes fishing at a weekend getaway and has a fish fry with their catch. Several of the family members fall sick, and when they were screened in the emergency room, test results show that benzene was consumed by the family members. The fish that were consumed evidently came from a lake that was contaminated. The following data set represents the level of benzene (in micrograms) that each member consumed. Within your response, please explain how you calculated your answer.

Given the data set 215, 501, 305, 298, 345, 305, 465, calculate the results below:a. mean,

b. mode,

c. median, and

d. standard deviation.Your response should be at least 300 words in length.

4) A population of individuals was exposed to lead contamination in drinking water at the concentration of 27 parts per billion (ppb). The following represents a small sample set from the population indicating the level of response to the contaminant rated on a scale from 1–20. Within your response, please explain how you calculated your answer (1 indicating minimal effects and 20 indicating maximum effects to the lead exposure).

Given the data set 9, 12, 7, 15, 8, 9, 10, calculate the following results:a. mean,

b. mode,

c. median, and

d. standard deviation.Your response should be at least 300 words in length.

Tox 3
BOS 4201, Toxicology 1 Cou rse Learning Outcomes for Unit III Upon completion of this unit, students should be able to: 2. Explain how toxins are processed in biological systems. 2.1 Calculate the mean, median, mode, and dispersion in different types of toxins. 3. Assess the environmental risk of chemical substances based on toxicity. 3.1 Differentiate between pollution and contamination. 3.2 Describe the processes by which chemicals move through the environment. Course/Unit Learning Outcomes Learning Activity 2.1 Unit Lesson, Unit Readings 3.1 3.2 Unit Lesson, Unit Readings Reading Assignment Chapter 5: Environmental Pollutants and Their Fate Chapter 6 : Dose and Response Unit Lesson This unit discusses the risks to the environment from chemical contamination. Historical incidents are explored in addition to the factors that affect the fate of chemicals in the environment. In the past , it was thought that dilution wa s the solution to pollution . Chemicals were released into the environment , and it was thought that these chemicals would just blow away until researchers found persistent chemicals in locations where they were not being used. As this became known, new tech nologies were invented to capture or reduce the amount of chemicals. Chemicals are found almost everywhere in our environment. They enter our food chain and can accumulate in animals. As humans, we are at the top of the food chain ; breastfeeding infant s i s at the highest level. I t has been theorized that infants are the most exposed group to environmental contaminants. UNIT III STUDY GUIDE Environmental Risks The pollution response unit at the Naval Air Station in Pensacola, Florida ., deploys oil containment booms at Sherman Cove to protect environmentally sensitive grass beds from the Deepwater Horizon oil spill on May 4, 2010. (Nichols, 2010) BOS 4201, Toxicology 2 UNIT x STUDY GUIDE Title Environmental Pollutants and Their Fate Pollution is defined as any change in the characteristic of the air, water, or soil that will adversely affect the health of an organism. A pollutant is any substance released into the environment that may cause adverse effects. The ecosystem is complex with abiotic and biotic fa ctors being interrelated. Pollutants are often introduced into the ecosystem and carried into the atmosphere. Precipitation — in the form of rain, sleet , or snow —can pull the pollutants from the atmosphere and deposit them onto land and into bodies of water , causing contamination in the soil and water. Below are s ome examples of common pollutants found in the environment :  gases (nitrogen oxides and sulphur dioxide) ,  metals (lead and mercury) ,  organics (benzene and toluene) ,  noise ,  photochemical oxidants (ozone), and  radioactive waste s. The fate of chemicals in the environment is affected by the process in which chemicals are moved and transformed in the environment. The process includes the following components:  persistence in air,  persistence in water,  persistence in soil,  reactivity and degradation,  migration in ground water, and  bioaccumulation in a quatic or terrestrial organisms. The persistence of a chemical in the environment is the ability of a chemical to remain unchanged in a particular environment. An example of a persist ent substance is PCB (polychlorinated biphenyl) . PCBs are a probable human carcinogen. They also have effects on the reproductive system, endocrine system, and the nervous system. The most common effects from exposure to PCBs are acne and rashes. Primary pollutants, such as nitrogen oxides , enter the air directly and can undergo chemical reactions and produce secondary pollutants like ozone. Nitrogen dioxide reacts with oxygen and ultraviolet light to form ozone ; o zone a nd nitrogen dioxide are lung irritants. Particles are also a concern as they vary in concentration and are categorized as PM 10 (particles less than 10 microns in diameter) and PM 2.5 (particles less than 2.5 microns in diameter) (Richards & Bourgeois, 2014) . Particle size is important as the smaller size penetrates into the gas exchange region of the lungs and contributes to lung disease. The fate of a chemical in the air depends on the rate of disposition and type of pollutant. The mixing with the air thro ugh vertical and horizontal transport, the chemical reactions, and the removal through precipitation contribute to this process . How the chemical is transported through the air and the presence of precipit ation can remove a chemical from the air and deposi t it into bodies of water or in the soil. Pollutants enter the water from run -off, atmospheric disposition, sewage treatment , accidental spills, and industrial discharge. Pollutants move throughout the water and can undergo chemical reactions. In addition , fertilizers from agricultural run -off cause the overgrowth of algae. Pollutants deposited into the soil , either deliberately or accidentally , can also undergo chemical reactions. BOS 4201, Toxicology 3 UNIT x STUDY GUIDE Title One environmental pollutant that has been in the news in recent years is dichlorodiphenyltrichloroethane , or more commonly referred to as DDT . DDT was originally developed in the 1930s to be used as an inse cticide (Richards & Bourgeois, 2014 ). DDT has been known for being a relatively inexpensive pesticide. The property of not degrading easily in the environment allows this insecticide’s effectiveness to extend long -term. The reason for DDT being in the news is for the negative effects of this environmental pollutant. Lab studies suggest DDT causes reproductive, teratogenic, and neurological effects on animals (Richards & Bourgeois, 2014). The more debated effects of DDT have been on the negative impact that some scientists believe DDT has had on the reproductive capacity of birds. Some researchers suggest that DDT has caused the weakening of the eggshells of some birds, causing the shells to crack and break, thus negatively impacting the ability of some birds to produce viable offspring. Other scientists have argued that the research has left gaps that fail to thoroughly support the claims (Richards & Bourgeois, 2014). Some researchers have gone as far as to claim that the data was falsified and that there was not any validity in the research on negative effects of DDT (Edwards , 2004). Mercury is an example of a highly toxic metal found in the environment. Elemental mercury is generally used in scientific instruments , and exposure occurs through absorption of the vapor into the body, which affects the central nervous system. Inorganic mercury causes damage to the kidneys. Organic mercury also affects the central nervous system. Mercury is also present in the environmen t because of the use of organomercury fungicides. It is also used in the manufacture of paper and plastics. Lead has long been recognized as an air pollutant, especially in young children and fetuses (Hodgson, 2010). Lead pollution sources include vehicle emissions and industrial processes. People are exposed to inorganic lead by ingestion and inhalation. Historically , lead poisoning in children came from paint , and the effect in children was usually encephalopathy with mental retardation. Lead is taken up by the red blood cells and distributed to the kidneys and liver. Some lead is also deposited into the bones. Lead also interferes with red blood cell production and causes the destruction of red blood cells, both of which lead to anemia. Organic lead , suc h as tetraethyl lead , is rapidly absorbed through the skin. The effects include delusion s and hallucinations. Arsenic is a metalloid found everywhere on Earth. Exposures usually occur through contaminated ground water. Long -term exposure to arsenic can re sult in various cancers ( e.g., skin, lungs, lymph glands) and hyperpigmentation of the skin (Hodgson, 2010). Noise is another type of pollution that is often overlooked. Noise pollution can come from automobile traffic, airplanes, trains , and machinery. I n addition to hearing loss, noise can cause other health effects such as hypertension, tinnitus, and cardiovascular disease. Poor urban planning has been a contributing factor to residential noise exposure. About half of all of the electricity generated in the United States comes from coal -fired power plants. (Stowe, 2009) BOS 4201, Toxicology 4 UNIT x STUDY GUIDE Title Light pollution is not mentioned in the textbook but is also another type of pollution that is not often discussed. Light pollution refers to artificial light that h as adverse effects on the environment. Light pollution wastes energy but can also disrupt the natural ecosystem. An example of light pollution affecting the environment would be artificial light interrupting young marine turtles, causing confusion in the d irection in which the hatchlings move when attempting to move toward the sea (Kamrowski, Limpus, Moloney, & Hamann, 2012). Endocrin e-disrupting chemicals cause changes in the endocrine system. It has been demonstrated that t hese chemicals are responsible for reproductive system dysfunctions. These chemicals can act as estrogen, anti – estrogen, or anti -androgens . T hey all result in an imbalance of hormones. Some examples of endocrine disrupting chemicals include DTT (organochlorine pesticides), PCBs (polych lorinated biphenyls), and alkylphenols. There has been an increase in breast cancer and testicular cancer since the 1940s, and it has been suggested that sperm counts are decreasing because of exposure to these chemicals. The food chain is another source of exposure to pollutants . An animal may not be able to eliminate a substance ; therefore , it will accumulate in the body . When that animal becomes prey for a predator, the predator is then exposed to the accumulated substance. Exposure to environmental pol lutants occurs through the pollution of the air, water, and soil. The fate of pollutants if affected by many factors and , as we have seen , there are primary and secondary pollutants. Metals are a common environmental pollutant of high toxicity. Endocrine -disrupting chemicals are becoming more of a concern as some cancer rates are increasing . Dose a nd Response The dose -response relationship is a fundamental principle that relates the amount of a toxicant received by the organism and relates that to the ef fect as a result to the dose. The establishment of a dose -response relationship provides information that serves to do several things such as those listed below:  establish the low -dose threshold ,  establish a quantitative relationship between the dose and the response ,  provide the basis causal relationship between the dose and the response , and  provide information to assess toxicity (Richards & Bourgeois, 2014 , p. 119 ). A normal distribution curve is commonly referred to as a bell curve. It represents a po pulation where the majority responds in a similar way with outliers on the extreme ends. The extreme ends of the bell curve are the hyporesponsive and hyperresponsive results ; the middle of the curve is where the majority of the population is represented. Scientists utilize and manipulate data statistically to analyze and interpret data. Methods of analyzing the results of the majority of the population involve calculating some of the central tendencies or averages in the population. Measures of central te ndencies include the mean, median , and mode. The mean is simply the average. This is calculated by adding all values and dividing by the number of values. Please view the video in the suggested reading section for a more in -depth explanation. When sea turtles hatch in areas with a lot of light pollution, they can get disoriented and not make it into the ocean. (Bend, 2017) BOS 4201, Toxicology 5 UNIT x STUDY GUIDE Title The median is the value that is in the middle. The median is determined as the middle value when all values are arranged from lowest to highest. Mode can be defined as the value that occurs most often. These measure ment s to identify the central tendencies of the pop ulation can then be used to compare how the entire set of values are distributed. Please view the video in the suggested reading section to learn more about figuring the mean, median, mode, and dispersion . The measures of dispersion are values that descri be how the data set is arranged. Measures that help to identify the range of dispersion include range , standard deviation , and variance . Range describes the extent or magnitude of the data set. Range can be calculated by taking the difference in the highes t and lowest value in the data set. Variance describes how far numbers in a data set are from the mean. Variance can be calculated by taking the sum of the differences between each value in the data set and the mean and then dividing it by one less than th e number of values in the set. Standard deviation describes how far values are from the normal. Standard deviation can be calculated by taking t he square root of the variance. When data is collected for a dose -response curve , it is useful to analyze and i nterpret the characteristics of the population by analyzing the measure ments of central tendencies as well as the dispersion of the data set. Below is an e xample of calculations for the following d ata set: 1, 2, 4, 6, 8, 7, 7, 9, 3, 10, and 5 . See the cal culations below.  Mean= sum of values/ # of values in data set o Mean= (1+2+4+5+6+8+7+7+9+3+10)/11 = (62/11) = 5.64  Median= # in the middle = 6 o 1, 2, 3, 4, 5, 6, 7, 7, 8, 9,10  Mode= value that occurs most often = 7 o 1, 2, 3, 4, 5, 6, 7, 7, 8, 9,10  Range= difference in the highest and lowest value in the data set o Range= 10 -1= 9  Variance= sum of the squared differences between each value in the data set and the mean and dividing it by one less than the number of values in the set: o Variance= [(1 -5.64) ²+(2 -5.6 4) ²+( 4-5.64) ²+( 6-5.64) ²+( 8-5.64) ²+( 7-5.64) ²+(7 -5.64) ²+( 9-5.64) ²+( 3-5.64) ²+( 10 -5.64) ²+(5 -5.64) ²]/(11 -1) o = ( -4.64)²+( -3.64)²+( -1.64)²+(0.35)²+(2.36)²+(1.36)²+(1.36)²+(3.36)²+( -2.64)²/(10)=65.1193/10= 8.454545  Standard deviation=square root of the varia nce = √6.51= 2.90767 References Bend, R. (2017). Episode 4: Teens & turtles [Photograph ]. Retrieved from https://www.flickr.com/photos/naturenps/32373344350/in/photolist -RjHRpu -6VPm7c -RjHQqf -peqQ8h – fwSRuY -arC3mh -74Z4ax -6KKZkb -54AeWX -j82492 -8Dg6zz -5xvX43 -cGJQuG -aPWd4v -8uf6Qq – axwn7v -6THzXW -akJmN3 -i2cunF -HRb7JK -biEAu4 -axuQvm -dJ1xzY -7y1XT8 -59qoNn -6ha7LK – 6HoppJ -e Casida, J. E., & Quistad, G. B. (1998). Golden age of insecticide: Past, present, or future? Annual Review of Entonology , 1 –16. Edwards, J. G. (2004). DDT: A case study in scientific fraud. Journal of A merican Physicians and Surgeons, 9, 83 –88. Retrieved from http://www.jpands.org/vol9no3/edwards.pdf Hogdson, E. (2010). A textbook of modern toxicology (4th ed.). Hoboken, NJ: Wiley. Kamrowski, R. L., Limpus, C., Moloney, J., & Hamann, M. (2012). Coastal light pollution and marine turtles: Assessing the magnitude of the problem. Endangered Species Research, 19 , 85 –98. Retrieved from http://www.int -res.com/articles/esr_oa/n019p085.pdf BOS 4201, Toxicology 6 UNIT x STUDY GUIDE Title Nichols, P. (2010). 100504 -N-6268N -027 [Photograph ]. Retrieved from https://www.flickr.com/photos/[email protected]/4581380809/in/photolist -mdp6sZ -kEKXsH -dk2bYL – nzWc1b -o7zmdx -o7zm2a -o7sD8Y -mYpJfc -dP5Y6A -nQziFu -o8ZmyE -daxKzZ -nCHxcG -gan2cN – fUTH42 -beUQJg -pRwa8c -o7sD5b -dqYQ1G -beUQPF -fV27je -fV28sX -fPQTE4 -9VgTne -pyHZg U- fV27V4 -nsJxcK Richards, I. S. , & Bourgeois, M. M. (2014). Principles and practice of toxicology in public health (2nd ed.). Burlington, MA: Jones & Bartlett Learning . Stowe, R. (2009). Coal -fired power plant [Photograph ]. Retrieved from https://www.flickr.com/photos/tomsaint/3518071026/in/photolist -6mT2X1 -eRLxAY -c1brCo -7NfoAM – qRZUhY -fTed1p -dFzEee -njrxMb -akexmA -6F1UTd -qh3z2G -ejU3Zo -dfsAP9 -9QYQSc -eTanGP -ic2r3h – ai7rPv -ahY85q -n8sA5z -tCkhF -jaPN4p -ahVyUD -7UHJtk -aRqg9P -ncvpau -ahY rJA -7PN1HL -6uQb Suggested Reading Click here to access the Chapter 5 PowerPoint presentation. Click here to access a PDF version of the presentation . Click here to access the Chapter 6 PowerPoint presentation. Click here to access a PDF version of the presentation . To learn more about the mean, median, mode, and dispersion, please click here to view the PDF created by Dr. Corcoran. In order to access the following resource, click the link belo w: Learn how to figure the median value of a set of numbers in the video below. Villiger, M. [Writer, Producer, & Director]. (2013). Measures of center: Against all odd s–inside statistics (Segment 3 of 6) [Video file] . Retrieved fr om https://libraryresources.columbiasouthern.edu/login?auth=CAS&url=http://fod.infobase.com/Por talPla ylists.aspx?wID=273866&xtid=111523&loid=401048 Click here to access the transcript for the video above. Learning Activities (Non -Graded) Non -Graded Learning Activities are provided to aid students in their course of study. You do not have to submit them. If you have questions, contact your instructor for further guidance and information. Research two extreme cases of environmental hazards, preferably in your county or state . Find t he reported source , and include any actual or potential health effects.

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