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What’s missing? Reactions/degradation Air Water Octanol A gas is a gas is a gas T, P Fresh, salt, ground, pore T, salinity, cosolvents NOM, biological.

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Presentation on theme: "What’s missing? Reactions/degradation Air Water Octanol A gas is a gas is a gas T, P Fresh, salt, ground, pore T, salinity, cosolvents NOM, biological."— Presentation transcript:

1

2 What’s missing? Reactions/degradation

3 Air Water Octanol A gas is a gas is a gas T, P Fresh, salt, ground, pore T, salinity, cosolvents NOM, biological lipids, other solvents T, chemical composition Pure Phase (l) or (s) Ideal behavior PoLPoL C sat w C sat o K H = P o L /C sat w K oa KHKH K ow = C sat o /C sat w K ow K oa = C sat o /P o L

4 Goals of this course To give you the tools necessary to evaluate the fate of organic chemicals in the environment in both a qualitative and quantitative way To develop your “chemical intuition”

5 Chemical intuition means that by looking at a chemical’s structure you can guess something about its: Henry’s Law constant K ow Aqueous solubility Reactivity These (few) properties will determine the chemical’s ultimate fate malathion phenol atrazine CCl 4 carbon tetrachloride Tetrachlorobiphenyl (a PCB)

6 Estimation Techniques These important parameters can be estimated (with varying degrees of success) from LFERs or bond-contribution methods (i.e. from the compound’s structure): Henry’s Law constant K ow Aqueous solubility Reactivity The wildcard is toxicity—difficult to estimate simply from a compound’s structure.

7 The whole world can be seen as a war between thermodynamics and kinetics In the first part of this course, we will concentrate on thermodynamics, i.e. equilibrium –Estimations of K aw, K ow, solubility, etc, which determine where a compound will ultimately end up. In the second part we will look at kinetics, i.e. the rate at which a chemical is transferred from one environmental compartment to another (or the rate at which it is transformed) –Air-water exchange, box models

8 Expect familiarity with: Chemical structures, bonding Saturated, unsaturated, aromatic Oxidation states Polarity, hydrogen bonding Functional groups containing O, S, P, N Heterocycles Electronegativity If these terms aren’t familiar, review Chapter 2. Basic thermodynamics  H,  S,  G

9 Resources available to you: Your book: it’s marvelous! (check out the appendixes!) However, notation can be difficult Online resources http://www.chemfinder.com/ http://webbook.nist.gov/ http://www.syrres.com/what-we-do/free-demos.aspx http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm www.wikipedia.com

10 There are more than 70,000 synthetic chemicals that are in daily use: –solvents –components of detergents –dyes and varnishes –additives in plastics and textiles –chemicals used for construction –antifouling agents –herbicides, insecticides,fungicides Why the interest?

11 Classes of compounds BTEX PAHs, including methylated PAHs Halogenated C 1 and C 2 compounds PCBs Chlorinated pesticides Brominated flame retardants

12 Formed from small ethylene radicals “building blocks” produced when carbon based fuels are burned Sources are all types of burning PAHs

13 Sources of PAH in New Brunswick (Gigliotti et al, 2003)

14 Some PAH structures anthracene phenanthrene fluoranthene naphthalene benz(a)anthracene benzo(a)pyrene [BaP]

15 Naphthalene, phenanthrene and anthracene are found in the gas phase pyrene and fluoranthene are in both the gas and particle phase BaA and BaP are mostly on the particles, Why??? PAHs

16 Metabolized to epoxides which are carcinogenic; O PAH are indirect acting mutagens in bacterial mutagenicity tests (Ames- TA98+s9) methyl PAHs are often more biologically active than PAHs PAHs

17 used as coolants - insulation fluids in transformers, capacitors, plasticizers, additives to epoxy paints are thermally stable and biologically stable can exist in the gas and particle phases Banned in the early 1970’s but still a big problem Polychlorinated biphenyls (PCBs)

18 Local PCB impacts GE ordered to spent approximately $450 million to dredge portions of the upper Hudson The Federal courts have ordered that a TMDL for PCBs must be established for the Delaware River EPA Water quality criteria: 44 pg/L NY state Water quality criteria: 1 pg/L Typical levels in these two rivers: 1,000-10,000 pg/L

19 What else is out there?

20 When the World Trade Center was destroyed USEPA and NYSDEC investigated its impact on water quality in New York Harbor Simon Litten, NYSDEC

21 The WTC contained about 1 gallon of PCB in the transformers. Pyrolysis of this material would form chlorinated dioxins and furans. Work performed by the NYSDOH in 1981showed that pyrolysis of PCB containing transformed fluid also produces chlorinated biphenylenes. A modern office building is expected to contain PBDEs. Pyrolysis of PBDEs is expected to produce brominated dioxins and furans. PBDD/Fs released into the environment are expected to undergo reactions where chlorines replace bromines. There 984 polyhalogenated (Br and Cl) dioxins/furans.

22 Tetra- and Pentachlorobiphenylenes Tetra > penta Pre-dated 9/11 in sediments Very little is known about toxicity

23 PBDEs Office buildings contain brominated flame retardants in computers, furnishings, and upholstery. Little is known about toxicity and background concentrations of these chemicals. Rector St. run-off contained high levels of deca-PBDE on 9/14


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