课件文稿说明教案5113w12lec introduction

1、IntroductionWeek 1, 21Instructors Prof. W-X Wang Every Tue night 630 pm2Course Goals To introduce the: Scope of ecotoxicology;Concepts and principles of ecotoxicology;Methods of study; To understand real environmental issues.Expectation for the course Use of basic principles to address applied probl

2、ems; Broaden the views of environmental issues.4Challenges for this course Biology vs. Chemistry.5Contents Introduction: Classes of pollutants (2) Pollutant behavior (2) Bioaccumulation (3) Biological responses (2) Biomonitoring, toxicity testing, case studies (3)67PollutantsBiotaFateTransportBioacc

3、umulationToxicityBiological levelEcotoxicologyEarly ages of toxicologyHeavy metal poisoning in Japan8Heavy metal poisoning in Japan Itai-Itai disease in the 1940-1960: Cd in rice (ouch-ouch joint pain).9Radionuclide pollution Nuclear bomb and testing: 1960s. Radionuclide discharge: 137Cs, 131I10Pest

4、icides pollution DDT, DDD, DDE (shell thinning of birds eggs) in 1970s. 111213More recent issues TBT: antifouling agents; Imposex in snails. Male organ in female. Oyster shell chamber.14Hg in fish and game15As in Asia16Nuclear accident in Japan (Fukushima).17Issues in Hong Kong: Hg in fish18Contamin

5、ated sediments19In China, history is repeated.20July 2010, Zijin Copper Mining.9100 m3 effluentsGreen and Blue Oysters newly discovered21Status We are practically doing experiments using human as subject. Outcome remains to be seen (but probably not very promising).22Ecotoxicology Introduced in 1969

6、, ecology + toxicology More environmentally relevant.23Definition of Ecotoxicology Ecotoxicology is the science of contaminants in the biosphere and their effects on constituents of the biosphere, including humans. the study of harmful effects of chemicals upon ecosystems.2425How is harm? harmful to

7、 one species may not be harmful to another. different levels (biochemical, organismic, ecosystem) will have different harmful effects.26Different biological levels All relevant levels should be considered; an exciting feature of ecotoxicology. Processes at one level take their mechanisms from the le

8、vel below and find their consequences at the level above.272829Blood3031Three aspects of study Scientific goals: knowledge-based development, including observations and experiments Technological goals: analytical techniques, biomarker, biomonitors, etc Practical goals: management issues, water quali

9、ty criteria, standards3233ValueTime to benefitgloballocalManagementScienceTechnolSome terms Pollutants: a substance in part as a result of mans activities, and which has a deleterious effect on living organisms. Contaminant: a substance released by mans activity (not necessarily adverse effect).34So

10、me terms Xenobiotics: a foreign chemical not produced in nature and not a constitute component of a specified biological systemusually applied to a manufactured chemical. Stressor: produce a stress, a response to a recent disorganizing or detrimental factor. 35Some slide showsField trip to a contami

11、nated estuary36Classes of Contaminants Metals and metalloids Organic pollutants Organometals Radionuclides37Metals/metalloids Heavy metals: density 5, less often used nowadays. Trace metals: in trace amount, ONS)2. Class B type: Ag+, Cu+, Cd2+, Hg2+, Sn2+ (FON1000% distributed0510152025301986-2000LC

12、EL: 65 mg kg-1UCEL: 110 mg kg-1Metals in PRE sediments4849Time trend50Organic compounds: containing carbon Oils PAHs PCBs Organochlorines 200,000 xenobiotics51Oils Gas, liquid, or solids. Low water solubility, high in organic solvents. Sources: deposits of petroleum and natural gas (fossil fuel), oi

13、l spillage.52Polycyclic aromatic compounds (PAH) Incomplete combustion (burning), 2-6 rings From: human activity or natural conditions5354benzenebenzopyrene55Polychlorinated biphenyls (PCB) Synthetic compounds, high molecular weight, low vapor pressure, low water solubility, and high stability Used

14、for dielectric fluids, heat transformer fluid, lubricants, vacuum pump fluids. Now banned.5657A total of 209 congeners, Cl content.Organochlorine pesticides/insecticide DDT, DDD, DDE (now dominated by DDD, DDE due to the bans of DDT and the metabolism/degradation of DDT). Stable solids, limited vapo

15、r pressure, low water solubility, high lipophilicity. DDT: World War II as vector control, then as disease and insecticide. Causing egg shell thinning.5859Chlorinated cyclodiene insecticides aldrin, dieldrin, heptachlor: after DDT, high toxicity, persistence. 1990: mostly banned for DDT and cyclodie

16、ne, but they are still detected in the environment due to their persistence.6061626364Dioxins Polychlorinated dibenzodioxins (PCDD) and dibenzofurans (PCDF): dioxins. 75 possible congeners of PCDD By-products from synthesis of other compounds, or combustion of PCBs Chemical stable with low water sol

17、ubilities (1 g/l).65666768Centre for Food SafetyWhy are we concerned about? Many of them are persistent; Many of them are bioaccumulative; Many of them are toxic; These PBT are the most important principles for organic pollutants.6970New Term: POPs71Emerging contaminants of concerns Newly released/discovered by advanced analytical technique, or transformed chemicals. Brominated diphenyl ether (PBDE): as flame retardants