ESSENTIAL QUESTIONS: How does chromium affect humans and how worried should we be about it?

Transcription

1 NAME ESSENTIAL QUESTIONS: How does chromium affect humans and how worried should we be about it? INTRODUCTION As we ve discussed as part of our research into the redevelopment of the West Side, one of the concerns that people have is that some of the new housing developments are being built on land that was contaminated by chromium from chemical plants that used to be located on the West Side of Jersey City. One of these sites is just down the street from UACHS, where NJCU is building its new West Side Campus, which will include a dormitory, a Shop-Rite, and a performing arts center. NJCU has had the chromium from the soil removed in one part of the site, but it has capped over the rest of the site, leaving the soil underneath the cap still contaminated by chromium. The following excerpt from an overview on chromium drafted by the U.S. Department of Health and Human Services Agency for Toxic Substances and Disease Registry summarizes where the various forms of chromium come from, what they are used for, and how they affect humans. Health Effects of Chromium by the Agency for Toxic Substances and Disease Registry, updated September 4, 2011 Introduction Chromium is a naturally occurring element found in rocks, animals, plants, soil, and in volcanic dust and gases in several different forms. Chromium(III) occurs naturally in the environment and is an essential nutrient required by the human body. Chromium compounds, mostly in chromium(iii) or chromium(vi) forms, produced by the chemical industry are used for chrome plating, the manufacture of dyes and pigments, leather tanning, and wood preserving. Pathways for chromium in the environment Chromium enters the air, water, and soil mostly in the chromium(iii) and chromium(vi) forms as a result of natural processes and human activities. The levels of both chromium(iii) and chromium(vi) in soil increase mainly from disposal of commercial products containing chromium, chromium waste from industry, and coal ash from electric utilities. Reflect on the essential questions: What kinds of information will you look for in the reading to help you answer the essential questions? What do you think it means that the second question asks how worried we should be about chromium? What does that suggest to you about the effects of chromium on humans? Reflect on the introduction: How is chromium involved in the redevelopment of the West Side? State this in your own words. What do you think it means that NJCU has capped part of the site where its new West Side campus will be located? What has been done about the chromium in the soil on that part of the site? Notice the author: Who is the author of this article (you may want to Google Agency for Toxic Substances and Disease Registry) and when was it last updated? Does this information make the excerpt seem credible? Why or why not? Key idea: What does it mean that chromium occurs in different forms? What is different about them? What does the Roman numeral after a transition metal represent? Is it a cation or an anion? Key idea: The introduction indicates that chromium is natural and required by the human body. Does that mean chromium is safe and healthy? Why or why not? Key idea: According to the article, how does chromium usually end up in soil? Based on this information, how might have chromium ended up in the soil under NJCU s West Side campus?

2 Most of the chromium in soil does not dissolve easily in water and can attach strongly to the soil. A very small amount of the chromium in soil, however, will dissolve in water and can move deeper in the soil to underground water. Exposure to chromium You can be exposed to chromium by breathing air, drinking water, or eating food containing chromium or through skin contact with chromium or chromium compounds. The level of chromium in air and water is generally low. Key idea: Based on the information in the article, how can chromium move into our water sources? Chromium(III) is an essential nutrient for humans. On the average, adults in the United States take in an estimated 60 µg of chromium daily from food. You may also be exposed to chromium from using consumer products such as household utensils, wood preservatives, cement, cleaning products, textiles, and tanned leather. You may be exposed to higher-than-normal levels of chromium if you live near the following: Landfill sites with chromium-containing wastes Industrial facilities that manufacture or use chromium and chromium-containing compounds Cement-producing plants, because cement contains chromium Waterways that receive industrial discharges from electroplating, leather tanning, and textile industries Health effects of chromium Chromium(III) is an essential nutrient that helps the body use sugar, protein, and fat. An intake of µg of chromium(iii) per day is recommended for adults. Without chromium(iii) in the diet, the body loses its ability to use sugars, proteins, and fat properly, which may result in weight loss or decreased growth, improper function of the nervous system, and a diabetic-like condition. Therefore, chromium(iii) dietary supplements are beneficial if taken in recommended dosages. Key idea: According to the excerpt, in what ways are people exposed to chromium? What puts people at greater risk to higher levels of chromium exposure? Key idea: What does chromium(iii) do for the body? State this in your own words. Does it matter how much chromium(iii) a person gets? Why or why not? In general, chromium(vi) is more toxic than chromium(iii). Chromium(VI) is believed to be primarily responsible for the increased lung cancer rates observed in workers who were exposed to high levels of chromium in workroom air. Breathing in small amounts of chromium(vi) for short or long

3 periods does not cause a problem in most people. Workers handling liquids or solids that have chromium(vi) in them have developed skin ulcers. Allergic reactions consisting of severe redness and swelling of the skin have been noted. Because some chromium(vi) compounds have been associated with lung cancer in workers and caused cancer in animals, the Department of Health and Human Services has determined that certain chromium(vi) compounds (calcium chromate, chromium trioxide, lead chromate, strontium chromate, and zinc chromate) are known human carcinogens. The EPA has determined that chromium(vi) in air is a human carcinogen. Health effects in children Children who live near wastes sites where chromium is found are likely to be exposed to higher environmental levels of chromium through breathing, touching soil, and eating contaminated soil. Children at age five years or younger have higher levels of chromium in their urine than do adults and children living outside of contaminated areas. We do not know if exposure to chromium will result in birth defects or other developmental effects in people. Birth defects have been observed in animals exposed to chromium(vi). Death, skeletal deformities, and impaired development of the reproductive system have been observed in the newborn babies of animals that swallowed chromium(vi). Studies with mice have shown that chromium crosses the placenta and concentrates in fetal tissue. Therefore, pregnant women who were exposed to chromium in the workplace or by living near chromium waste sites may transfer chromium from their blood into the baby where it may build up at levels greater than in the mother. There is some evidence in humans that chromium can be transferred from mother to infant through breast milk. Medical tests for exposure to chromium Chromium can be measured in the hair, urine, serum, red blood cells, and whole blood. However, since chromium(iii) is an essential nutrient, low levels of chromium are normally found in body tissues and urine. Tests for chromium exposure are most useful for people exposed to high levels. These tests cannot determine the exact levels of chromium you may have been exposed to or predict whether or not health effects will occur. Key idea: According to the excerpt, what are the health effects of exposure to high levels of chromium(vi)? What about exposure to small amounts? Summarize these effects in your own words. Vocabulary: What does it mean, according to the article, that certain chromium(vi) compounds... are known human carcinogens? What kinds of effects have they caused in humans and animals? How many oxygens are there in chromium trioxide? Is this ionic, covalent, or metallically bonded? Notice: According to the article, what are the consequences for children of living near areas contaminated by chromium? What scientific evidence does the paragraph offer to support that claim? Key idea: According to the article, how are newborn animal babies affected by chromium exposure? Summarize these effects in your own words. What does this suggest about how chromium might affect human babies? What evidence does the paragraph offer to indicate how human infants might be exposed to chromium? Key idea: What can tests that measure chromium in our bodies tell us? What do they not tell us?

4 CHECK FOR UNDERSTANDING 1. Which of the following statements best states the main idea of the article? a) Exposure to any form of chromium at any level is highly dangerous to people. b) Chromium is not that harmful, so people should not be so afraid of areas that are contaminated by it. c) Chromium can cause serious health problems in people depending on what form and how much someone is exposed to. d) Children are much more likely to be exposed to chromium than adults. 2. Which THREE of the following support your answer to question 1? a) Chromium(III) occurs naturally in the environment and is an essential nutrient required by the human body. b) The level of chromium in air and water is generally low. c) In general, chromium(vi) is more toxic than chromium(iii). d) Without chromium(iii) in the diet, the body loses its ability to use sugars, proteins, and fat properly, which may result in weight loss or decreased growth, improper function of the nervous system, and a diabetic-like condition. e) Tests for chromium exposure are most useful for people exposed to high levels. f) Workers handling liquids or solids that have chromium(vi) in them have developed skin ulcers. g) The EPA has determined that chromium(vi) in air is a human carcinogen. 3. According to the excerpt, Studies with mice have shown that chromium crosses the placenta and concentrates in fetal tissue. Therefore, pregnant women who were exposed to chromium in the workplace or by living near chromium waste sites may transfer chromium from their blood into the baby where it may build up at levels greater than in the mother. As used in this context, concentrates means a) decreases b) thinks carefully c) collects d) damages 4. Which of the following words or phrases best helps you determine the meaning of concentrates in the above passage a) exposed to chromium in the workplace b) Studies with mice c) crosses the placenta d) build up at levels greater than in the mother 5. Which of the following questions is NOT answered by the excerpt? a) Does chromium cause birth defects in people? b) How does chromium get into the air, soil, and water? c) How do children and adults get exposed to chromium? d) Which form of chromium seems to be more toxic than others?

5 OPEN-ENDED RESPONSE You have read a government report on chromium and a news story about NJCU s West Campus ( aim.html). Using evidence from both articles, write an essay exploring the issue of chromium contamination and NJCU s West Campus. Based on what you have read, what specific risks does the construction on the West Campus pose? Does the scientific research support the idea that this construction is safe? Explain your thinking using specific references from both articles.

6 Answers: 1. C 2. C,F,G 3. C 4. D 5. A

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