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Zinc. Jessica Young. Structure & Properties. Zn Atomic number: 30 5 Stable isotopes Zn 64 , Zn 66 , Zn 67 , Zn 68 , Zn 70 Many radio isotopes Zn 65 , Zn 72 Exists in oxidation states Zn, Zn 1+ , Zn 2+ Also found in many compounds ZnO , ZnCl 2 , ZnS , and ZnSO 4
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Zinc Jessica Young
Structure & Properties • Zn • Atomic number: 30 • 5 Stable isotopes • Zn64, Zn66, Zn67, Zn68, Zn70 • Many radio isotopes • Zn65, Zn72 • Exists in oxidation states • Zn, Zn1+, Zn2+ • Also found in many compounds • ZnO, ZnCl2, ZnS, and ZnSO4 • Relatively long half life (4.3 X 1018 years)
Uses & Applications • Oxidated form (Zn2+) occurs naturally in minerals in the earth’s crust (70 mg/kg) • Anthropogenic sources • Smelting • used to protect against corrosion • Batteries • Brass & Bronze manufacturing • Brakes and car exhaust found to be leading cause of zinc pollution in Sao Paulo, Brazil study
Uses & Applications • Applications of zinc compounds • Herbicides, medical and dental products, household items (makeup, shampoo, sunscreen)
Zinc in Aquatic Environments • How it gets there… • Industrial & urban runoff • Cations, zinc-inorganic coumpoudns, zinc-organic compouds • Zinc ions have a low mobility in sediment and are readily taken up by plants and animals • Bioconcentration factors estimated to be 1000 and 2000 for freshwater and marine fish, respectively
Properties in water • As a cation, it is non soluble in water and is partitioned into sediment by adsorption onto organic molecules • Other common forms are much more soluble • ZnCl2 • ZnSO4 • Other solubility factors • Temperature • pH • Mineral composition of water
Necessity & Toxicity • Zinc is an essential micronutrient found in most foods; absorbed through gastrointestinal tract • Necessary for enzyme function • Miners exposed to acute high levels of zinc oxide in the air experienced respiratory problems • Interference with absorption of copper and iron • Effects on cardiovascular, respiratory, and immune systems • Low leves of HDL • Stimulated production of amylase and lipase by pancreas • One incident of human fatality attributed to zinc overdose
Zinc at the Colorado Lagoon • 33.18 mg/ kg in site 5 sediment sample • 35.19 mg/kg in site 8 clam tissue • CO Lagoon clams contains 16 mg/ pound • Recommended Daily Allowance is 8-11 mg/ day • Tolerable Upper Limit is 40 mg/ day
Detoxification • Metallothionine (MT) • Cysteine rich proteins found in Golgi • Found to play key role in uptake, regulation, and distribution of zinc in organisms • Zinc is efficiently regulated in mammals and excess zinc can be excreted via nephridial system
References EPA; 2005; Toxicological Review of Zinc and Compounds http://www.epa.gov/iris/toxreviews/0426tr.pdf Gioia, S., Weiss, D., Coles, B., Arnold, T., Babinski, M.; 2008; Accurate and Precise Zinc Isotope Ratio Measurements in Urban Aerosols; Analytical Chemistry; v. 80 (24); p. 9776-9780 http://pubs.acs.org/doi/pdf/10.1021/ac8019587 Skidmore, J. F.; 1964; Toxicity of Zinc Compounds to Aquatic Animals, with Special Reference to Fish; The Quarterly Review of Biology; V. 39 (3); p. 227-248 http://www.jstor.org/stable/2820034 US Dept of Health and Human Services, Agency for Toxic Substances and Disease Registry; 2005; Toxicological Profile for Zinc http://www.atsdr.cdc.gov/ToxProfiles/tp60.pdf National Institutes of Health, Office of Dietary Supplements http://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/ Sigel, Astrid; Sigel, Helmut; Sigel, Roland K. O.; Metallothionines and Related Chelators; Metal Ions in Life Sciences; v. 5; http://www.springer.com/chemistry/inorganic+chemistry/book/978-1-84755-899-2?detailsPage=reviews Zinc Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Reviewhttp://www.pwrc.usgs.gov/infobase/eisler/chr_26_zinc.pdf