Environmental Toxicology Final Examination Monday, April 26, 2004

Transcription

1 Environmental Toxicology Final Examination Monday, April 26, 2004 Name For questions 1-14, circle the letter corresponding to the correct statement(s). Any number of selections may be correct. Incorrect responses deducted from your score (5 each). 1. The following are correct toxin:antidote (or treatment) combinations: a. strychnine: KMnO 4 b. carbaryl: 2-PAM c. DNOC: atropine d. malathion: atropine e. Rotenone: 2-PAM 2. The following are true for organophosphates: a. inactivated with tap water b. require metabolism to the phosphorthioate for toxicity c. phosphoryl group binds to anionic site in acetylcholinesterase d. invented by Iraqi scientists e. TOTP causative agent of Ginger Jake Shuffle 3. The following are true for organophosphates: a. p-nitrophenol is biomarker for parathion exposure b. the two antidotes can be given in any order just as long as both are given c. short environmental half-life d. symptoms begin almost immediately e. less groundwater residues than DDT 4. The following statements are true for methylisocyanate (MIC): a. few persistent effects in exposed people b. longer t½ in the body if food is in the stomach c. starting material to produce the rodenticide Sevin d. indiscriminate toxin due to extreme chemical reactivity e. increased PCO 2 in exposed people 5. The following are from natural sources: a. strychnine b. sarin c. rotenone d. atropine e. warfarin 6. The following form epoxide intermediates: a. aromatic amines b. organophosphates c. PAHs d. MIC e. benzene 7. The following must be metabolically activated for toxicity: a. aromatic amines b. PAHs c. carbaryl d. MIC e. vinyl chloride 1

2 8. The following are true for dioxin: a. contaminants from paper bleaching b. major source is municipal waste incineration c. people less susceptible than rodents d. caused disaster at Three Mile Beach e. affinity for cytosolic receptor about same in rats and people NH Cl O N N Cl OCH 2 C-OH H 3 C N N CH 3 A NH 2 B C 9. The following are true for the above herbicides (a-c): a. c lung toxicant b. a thyroid toxicant c. c marijuana eradication d. a sprayed on USU campus lawns e. b effective against Dyer s woad 10. Chemodynamics in clay for the above herbicides (a-c; all else equal): a. binding: c > b b as ph decreases, a becomes more anionic, binding increases c. as ph decreases, b becomes more cationic, binding increases d. as ph increases, a becomes more cationic, binding increases 11. The following are true for xenoestrogens: a. bisphenol A is an estrogenic food additive b. TCDD is potent estrogen c. cell growth in estrogen-sensitive tissues protects against cancer d. are foreign chemicals that bind with estrogen receptor e. males don t have estrogen receptors, so are not at risk to these chemicals. 12. The following are correct toxin: mechanism pairs: a. CN - : blocks TCA cycle b. 1080: blocks TCA cycle c. benzene: DNA binding d. warfarin: inhibits Ca +2 uptake e. DNOC: uncouples oxidative phosphorylation 13. The following are characteristics of aromatic amines: a. amino group endocyclic b. in dyes, cigarette smoke c. nitrene is reactive intermediate d. some are known bladder carcinogens e. α-amino less carcinogenic than β 14. If TCE has a zero-order intake of 0.02 µg/day and eliminated at day -1, then: a. t½ =693 days b. t½ = 346 days c. Xmax=20 mg d. Xmax=0.02 mg e. time-to-xmax=4,851 days 2

3 15. Utah has the world s largest stockpile of nerve gas ordnance. Accidental poisonings in contract personnel destroying these stockpiles is a concern. In and organized outline, provide a hazard assessment including the following details: a) name 2 representative nerve gas agents b) history of their development; c) their acute potency relative to related compounds, like organophosphates, and the underlying reasons for this potency; d) characteristics of disposition (absorption, distribution, metabolism and elimination) in the body; e) treatment for poisoning and prognosis for recovery after treatment; f) strategies for safety assurance (poisoning avoidance, treatment, decontamination, monitoring worker safety, biomarkers, etc.); g) environmental fate and persistence (15). 3

4 16. The following are short-answer questions (3-4 sentences; 20). Why are potently toxic chemicals sometimes used as antidotes? Give two examples. Barbiturate (sodium barbituric acid, pka = 7.3) overdose is often treated with i.v. sodium bicarbonate. Explain the basis for this therapy. Sometimes the very young or the health-conscious gets cancer, while the 95-year old lifelong smoker doesn t. Two main reasons why amphibole is regarded as the more potent and higher risk form of asbestos compared to serpentine types 4

5 17. Briefly explain (1-2 sentences) the following toxicological phenomena (2 each): thallium is a popular poison for murders unbleached (brown) paper is increasingly used for consumer items like coffee filters warfarin poisoning in people is rare Bay region PAHs are more carcinogenic than those without a bay region 2-PAM not used in treatment of malathion poisoning: terracing gardens with used railroad ties is a bad idea: PAHs naturally occur in the environment: 5

6 18. According to the National Cancer Institute, 35-45% of all human cancers are caused by diet and environment. Describe in sequence, the major biochemical, molecular and pathologic events in multi-step carcinogenesis. Include the major events discussed in class, starting from exposure through to cancer, with the many intermediate modifying factors that affect tumor development. (15) 19. Super bonus question: Name these actors who appeared in Toxicology Goes Hollywood: 6