C2003 – ENVIRONMENTAL CHEMISTRY Course goals: After this course, students should be able to:  understand problems related to pollution of the environment from natural and anthropogenic sources Understand the pollutants Understand the environment (and how this relates to the pollutants) Understand how we measure pollutants in the environment Understand the ways that we use environmental data – risk assessment and environmental policy Week 1 Week 2 Week 3 Week 4 Goals in detail... Understand the pollutants:  characterize the main types of pollutants, mainly those that are non-degradable or persistent, have the ability to accumulate in abiotic and biotic compartments, posses a broad range of toxic effects, and can be transported to long distances  describe basic properties of these chemicals, their occurrence, sources, and how they enter the environment  understand relations between the chemical structure of chemical substances, their physical-chemical properties and their fate in the environment Understand the environmental compartments (and how these relate to the pollutants):  interpret the environmental fate of chemical substances, their environmental transport, interphase transport, phase equilibria and environmental biotic and abiotic transformation  characterize properties of environmental compartments (atmosphere, hydrosphere, pedosphere, biosphere) and combine this knowledge with the presence and fate of chemical compounds in these compartments  explain the relationships between the pollution sources and primary and secondary types of pollution of environmental compartments  understand the impact of environment properties on the fate of chemicals Understand how we measure these pollutants in the environment:  describe purposes and principles of the activities focused on screening and monitoring of presence of anthropogenic chemicals in the environment  distinguish between specific sampling methods for determination of volatile, non-volatile, polar and non-polar compounds in air, water, sediment, soil and biota  review the analytical techniques for the sample preparation, clean-up and fractionation  select the best analytical methods for the individual groups of chemicals  compare the separation and identification techniques and their applicability for determination of various organic chemicals in the environmental samples  define fundamentals of chromatographic and mass spectroscopy methods  introduce the quality assurance/quality control measures - understand the whole concept of chemical analysis of the environmental samples Understand the ways that we use environmental data: risk assessment and environmental policy  characterize and discuss environmental and health impacts of pollution  describe and discuss legislation and policy of these compounds and international conventions What is pollution?  Presence of a substance in an environmental system having a harmful effect  The substance = pollutant or contaminant Pollutants Natural Radon Heavy metals Anthropogenic PCBs Pesticides Flame retardants Just a few examples... Pollution depends on context...  Many are have both natural and anthropogenic sources (e.g., PAHs, metals...)  Only a pollutant when unwanted adverse effect:  E.g., ozone, pesticides... http://spaceplace.nasa.gov/greenhouse/en/ Environmental chemistry  Environmental chemistry is the study of chemical processes occurring in the environment which are impacted by human activities.  Can be local scale, e.g., urban air pollutants or toxic substances from a chemical waste site -or Can be global scale, e.g., long-range pollution transport, global warming Why is chemistry important to understand pollution? A chemical’s structure dictates that compound’s “personality,” - provides a systematic basis to understand and predict chemical behavior in the environment - With and understanding of the properties and behaviour of chemicals, we can better understand what the impact of humans is on the global environment Schwarzenbach et al. Environmental Organic Chemistry Types of pollutants  Many classes and methods for classification exist – we will consider a few of the major types of pollutants:  Volatile organic compounds  Airborne particulate matter  Persistent organic pollutants  Polycyclic aromatic hydrocarbons  Heavy metals  etc. Air pollutants  Airborne particulate matter, volatile organic compounds (VOCs)  primarily air pollutants  5 major air pollutants:  Particulate matter  Ozone  Nitrogen dioxide  Sulphur dioxide  VOCs World Health Organization, 2005 Air Quality Guidelines Particulate matter (PM)  Solid and liquid particles suspended in air  Naturally occurring and anthropogenic  Natural sources:  Salt particles from sea spray, pollen, moulds, bacteria, debris from plants and animals, soil particles entrained by wind, etc.  Anthropogenic sources:  Industrial processes, open burning, vehicles, agriculture, mining, etc.  PM is not a specific chemical, but a mixture of particles with different origin, composition, size, shape, etc.  Important itself (e.g., has negative health effects) and as a carrier for other atmospheric pollutants Particulate matter PM sizes and examples From Finlayson-Pitts and Pitts, 2000, Chemistry of the Upper and Lower Atmosphere Particulate matter Van Donkelaar et al. EHP 2015 Particulate matter – excluding dust and sea spray Particulate matter - exposure European Environment Agency: "Particulate matter is the air pollutant that poses the greatest health risk to people in Europe." European Guideline – annual average PM10 should not exceed 40 μg/m3 Smog formation  The word comes from the combination of “smoke” and “fog”…appropriate for original smog that was largely composed of soot particles from burning coal  Today - photochemical smog (“modern” smog) – typically related to vehicle emissions  Composed of particles and ozone and other secondary pollutants (e.g., peroxyacyl nitrates)  3 “ingredients” to make photochemical smog:  Light  Hydrocarbons, such as VOCs  A source of atmospheric radicals, such as NOx Ingredients for smog  VOCs – benzene, acetylene, xylene, acetone, toluene, etc.  NOx – nitrogen oxide compounds: NO and NO2 Sunlight can break down nitrogen dioxide (NO2) back into nitrogen oxide (NO). NO2 + sunlight  NO + O The atomic oxygen (O) formed in the above reaction then reacts with one of the abundant oxygen molecules producing ozone (O3). O + O2  O3 Nitrogen dioxide (NO2) can also react with radicals produced from volatile organic compounds in a series of reactions to form toxic products such as peroxyacetyl nitrates (PAN). NO2 + R  products such as PAN Also: O3 + NO  NO2 + O2 NO + RO2  NO2 + other products NO2 – global distribution Geddes et al. EHP, 2015 Case study 1: Los Angeles Smog  1943 – Los Angeles suffers extreme smog – irritation to eyes and breathing, visibility <3 blocks  Smog problems continued throughout 1940s and 1950s  Early 1950s: car emissions identified as contributing factor to smog  LA geography made smog worse UCLA Archives Types of pollutants  Many classes and methods for classification exist – we will consider a few of the major types of pollutants:  Volatile organic compounds  Airborne particulate matter  Persistent organic pollutants  Polycyclic aromatic hydrocarbons  etc. + others = SEMI-VOLATILE ORGANIC COMPOUNDS What are semivolatile organic compounds (SVOCs)?  Not a firm grouping  Generally determined by vapour pressure  typically between ~1 and 10-10 Pa Why are they important? • Can distribute in multiple media (gas-phase air, particle-phase air, soil, water, plants, lipids, floor dust, window films…) • Many are persistent, lipophilic, bioaccumulative • Many chemicals of concern are in this group. Examples of SVOCs  Pesticides  Industrial chemicals  By-products  Additives in consumer products POPs / PBT  Many SVOCs are classified as “persistent organic pollutants” (POPs) or “persistent, bioaccumulative and toxic” (PBT)  3 key terms to understand:  Persistence  Bioaccumulation  Toxicity Environmental Persistence  The length of time a chemical remains in environmental system or media  Governed by the rates at which the compound is removed from the system by biological and chemical processes, such as environmental transport, biodegradation, hydrolysis, atmospheric reactions  Measured as the half-life of the substance in the medium  A chemical is considered persistent if it has a half-life of:  >2 days in air  ~2-6 months or more in water, sediment or soil Bioaccumulation  The accumulation of a chemical in tissues of an organism through any route, including respiration, ingestion, or direct contact with the contaminated environment i.e. Rate of chemical uptake >> rate of chemical loss  If a chemical is “bioaccumulative” this means that the concentration of the chemical in the tissues of an organism can be significantly higher (e.g., several orders of magnitude) than the concentration of the chemical in the surrounding environment  Measured by bioaccumulation factor (BAF)  BAF > ~1000 means a chemical is considered “bioaccumulative” BAF = Conc. on contaminant in organism Conc. on contaminant in ambient environment Toxicity  A measure of the amount which a substance can cause harm to an organism  Related to the dose of a chemical received by and organism  moderately toxic substance can cause harm if an organism receives a higher dose  Highly toxic substance can cause harm at low doses Examples of SVOCs  Pesticides  Industrial chemicals  By-products  Additives in consumer products Pesticides – intentionally toxic! Chemicals designed to kill, reduce or repel pests Insecticides Herbicides Fungicides Rodenticides Insects Weeds Moulds Rodents How pesticides enter the environment Langenbach. “Persistence and bioaccumulation of Persistent Organic Pollutants” 2013 Global pesticide use Insecticide Herbicide Fungicide 2.5 million tonnes per year (Alavanja, 2009) From FAO Statistical Yearbook, UN 2013 Most common pesticides  In 1960s...  Today... Organochlorine pesticides  OCPs = organochlorine pesticides  What are the OCPs?  DDT  Hexachlorobenzene (HCB)  Pentachlorobenzene (PeCB)  Hexachlorocyclohexanes (multiple isomers)  Heptachlor/heptachlor epoxide  Aldrin/dieldrin/endrin  Chlordane (multiple isomers)  Endosulfan  Mirex  … Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Mirex HCHs α β γ Cl Cl Cl Cl Cl PeCB Cl Cl Cl Cl Cl Cl HCB Endosulfan Aldrin Dieldrin Endrin cis-chlordane trans-chlordane trans-nonachlor heptachlor Chlorinated molecules – highly stable – therefore environmentally persistent Case study 2: DDT  DDT – dichlorodiphenyl trichloroethane ClCl Cl Cl p,p'-DDD ClCl Cl Cl p,p'-DDE ClCl Cl Cl Cl p,p'-DDT ClCl Cl ClCl o,p'-DDT Degradation products/metabolites are often also considered: Chemical DDT vs. Technical DDT  Chemical DDT – dichlorodiphenyltrichloroethane, generally p,p’-DDT – the isomer with insecticidal properties  Technical DDT – mixture of p,p’-DDT, o,p’-DDT, DDE and DDD  DDE and DDD are impurities in technical mixture and breakdown products of DDT ClCl Cl Cl Cl p,p'-DDT p,p’-DDT: 63-79% o,p’-DDT: 8-21% p,p’-DDD: 0-4% o,p’-DDD: 0-0.05% Active ingredient Impurities DDT – a brief history 1872 – DDT was first synthesized by Austrian chemistry student 1939 – insecticidal properties discovered WW2– global use of DDT against typhus, malaria 1945 – DDT available to public 1940s, 1950s – WHO and country-specific programs targeting elimination of malaria – successful in Europe and North America, and large reduction in cases in India, southeast Asia DDT – a brief history 1959 - More than 36 million kg of DDT was sprayed over the US 1961 - DDT use reaches its peak. 1962 - Rachel Carson’s book Silent Spring blamed environmental destruction on DDT. “The toxicity of DDT to Certain Forms of Aquatic Life” 1945 1946: 1947: 1940s, 1950s – Gradual increase in number of scientific studies identifying negative effects of DDT on wildlife DDT – a brief history 1972 – DDT ban in USA and Canada 1974 – DDT ban in Czechoslovakia 1970s, 1980s –ban on DDT in many countries 2001 – Stockholm Convention on POPs – DDT is banned with limited exceptions for malaria control Currently From Czech National Implementation Plan for Stockholm Convention Where is DDT still used? Legally – for malaria control:  Botswana, Eritrea, Ethiopia, India, Madagascar, Marshall Islands, Mauritius, Morocco, Mozambique, Namibia, Senegal, South Africa, Swaziland, Uganda, Venezuela, Yemen, Zambia  Illegal use continues in limited locations? DDT – What are the concerns? Persistence, toxicity, long-range transport and bioaccumulation/biomagnification! What are typical trends in DDTs? SumDDT compounds in ice core from Mt. Everest glacier (Wang et al., Atmospheric Environment, 2008) DDT compounds in precipitation from North America, 1995-2005 (Sun et al., Environmental Science and Technology, 2006) What are typical trends in DDTs? Time  Conc.(ng/g) SumDDT compounds in herring fish from Sweden from 1977-1995 A. Polder , C. Thomsen , G. Lindström , K.B. Løken , J.U. Skaare Levels and temporal trends of chlorinated pesticides, polychlorinated biphenyls and brominated flame retardants in individual human breast milk samples from Northern and Southern Norway Chemosphere, Volume 73, Issue 1, 2008, 14 - 23 Time trend of levels of HCB, sum-DDTs and sum-PCBs in breast milk DDT – remaining questions? Replacements for OCPs  Current pesticide use is 2.5 million tonnes per year (Alavanja, 2009)  OCPs are generally no longer used:  ~5000 tonnes DDT (produced in China, India and North Korea)1 – 0.2% of global use  Only 6 countries reporting use of other OCPs (Ecuador, Honduras, Iran, Lesotho, Madagascar, Tajikistan, Ukraine) - ~2300 tonnes total in 20112  Replacement pesticides should have lower persistence and bioaccumulative potential 1 Van den Berg, EHP 2009; 2 FAO Statistics (faostat.fao.org); Currently used pesticides  Glyphosate (“Round-up”)  Herbicide  In use since 1970s  Most widely use chemical pesticide in world  ~650000 tonnes per year (>30% of world pesticide market)  Atrazine  Herbicide  banned in EU but high use in many other countries  70000 tonnes per year  Chlopyrifos  Most widely used insecticide  170000 tonnes per year (~7% of world pesticide market) Comparing 2 insecticides: Chlorpyrifos vs. DDT DDT  Vapour pressure: 0.0003 Pa  Solubility: 0.025 mg/L  Half-life in soil: 2-15 yrs  Overall environmental half-life: 1-5 yrs  Characteristic travel distance: 255 km Chlorpyrifos  Vapour pressure: 0.001 Pa  Solubility: 2 mg/L  Half-life in soil: 60-120 days  Overall environmental half-life: 30 days  Characteristic travel distance: 62 km Data from Pesticide Information Profiles, Extoxnet, Cornell University; and Mackay et al. 2014 Any questions about pesticides? Examples of SVOCs  Pesticides  Industrial chemicals  By-products  Additives in consumer products Polychlorinated biphenyls - PCBs Use •Discovery of compound, of useful properties •Spread of use Concern •Increasing number of scientific studies identifying concern •Push-back from industry •Weight of evidence Consequences •Regulation •Phase-out •Environmental problem -High chemical and physical stability, even at high temperatures Desirable property! - Industrially produced in 10 countries for a range of uses - Can also occur as a by-product of some industrial processes, esp. cement production and pulp and paper industries - First detected in environment in Swedish fish in 1966, many more reports followed - Concerns about environmental persistence and bioaccumulation - Production and new use banned by many countries in 1970s, 1980s - Banned under Stockholm Convention But...PCBs remain in use in old building equipment, electrical equipment, etc. PCBs – chemical structure Cl Cl Cl Cl Cl • 209 possible congeners • 1 to 10 chlorines • only 130 were used commercially • Classified based on degree of chlorination 2,3',4,4',5-Pentachlorobiphenyl PCB 118 Indicator PCBs – 7 congeners: PCB 28 PCB 52 PCB 101 PCB 118 PCB 153 PCB 138 PCB 180 PCBs – health effects  Acute vs. chronic effects  Associated with cancer, liver function, skin effects at occupational exposure levels  Prenatal exposure slows development in children  Some evidence of link with breast cancer  Dioxin-like PCBs What were PCBs used for?  Transformers and capacitors  Other electrical equipment including voltage regulators, switches, reclosers, bushings, and electromagnets  Oil used in motors and hydraulic systems  Old electrical devices or appliances containing PCB capacitors  Fluorescent light ballasts  Cable insulation  Thermal insulation material including fiberglass, felt, foam, and cork  Adhesives and tapes  Oil-based paint  Caulking  Plastics  Carbonless copy paper  Floor finish Sanexen Environmental Services PCB production over 1 million tonnes globally Why are PCBs still in use?  Because they are so useful for their purpose!  Where they were used was not well-documented  Challenges with removing all PCBs from use – current legislation only requires PCBs to be removed at >50 ppm CN Tower, Toronto, Canada CN Tower Built 1972 Had transformer containing PCBs Transformer is located in viewing area, 342 m high Had to be cut apart by hand Too big to be taken down elevator Packed piece-by-piece into steel drums, removed by elevator Any questions about PCBs? Examples of SVOCs  Pesticides  Industrial chemicals By-products  Additives in consumer products By-products  By-products of industrial processes, combustion  Unintentionally produced during industrial processes, fossil fuel combustion for heating, transportation, etc.  Examples:  Polycyclic aromatic hydrocarbons  Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans Dioxins and furans Dioxins in the news... Dioxins and furans – chemical structures O ClCl Cl Cl Cl Cl O Cl ClCl Cl Cl ClCl O Cl ClCl Cl Cl Cl Cl Cl O Cl ClCl Cl ClCl O Cl ClCl Cl ClCl O Cl ClCl Cl Cl Cl O Cl ClCl Cl Cl O Cl ClCl Cl O O Cl Cl ClCl Cl ClCl Cl O O Cl Cl ClCl Cl ClCl O O Cl Cl ClCl Cl Cl O O Cl Cl ClCl Cl Cl O O Cl Cl ClCl Cl Cl O O Cl Cl ClCl Cl DioxinsFurans Sources of PCDD/Fs  Unintentionally produced  During inefficient/incomplete combustion, especially waste burning  By-product from chemicals manufacturing  Major sources are: waste incineration, automobile emissions, metal industries, burning of peat, coal, wood PCDD/F Source Inventory Australia, Cambodia, Sri Lanka – Main source to air is open burning Secondary sources are: Australia – metal production Cambodia and Sri Lanka – waste incineration and heat and power generation Spatial patterns of PCDD/Fs  Higher concentrations closer to sources, in highly developed, industrialized areas  Concentrations patterns in air, soil, sediment and biota mirror each other  Trends on a large scale – globally – and small scale - locally Local scale – PCDD/Fs in soil around an incinerator Goovaerts et al. 2008 Bignert et al. 2007 Regional scale – PCDD/Fs in fish from the coast of Sweden Polycyclic Aromatic Hydrocarbons (PAHs)  By-products of combustion or fossil fuel processing  Composed of two or more aromatic rings  Many possible structures, but typically 3 to 6 rings PAH Sources Zhang and Tao, Atmospheric Env. 2009 PAHs over the past 300 years Gabrieli et al. 2010 Any questions about PCDD/Fs or PAHs? Examples of SVOCs  Pesticides  Industrial chemicals  By-products  Additives in consumer products Additives to consumer products  Flame retardants  Plasticizers Flame retardants – organic or inorganic chemicals added to consumer products (furniture, electrical appliances, electronics) to suppress/delay/prevent the spread of fire Plasticizers – additive chemicals that increase the flexibility, softness, fluidity of a material. Largely used in plastics. Flame retardants 72 • To slow the spread of flames • Organic or inorganic • Wide range of applications (furniture, electronics, industrial/workplace textiles and protective equipment, vehicles) • Required by fire safety regulations http://www.jptarpaulins.com/ PBDEs  Polybrominated diphenyl ethers  Flame retardants  Classified by either technical mixture or congener group  Confusing!! E.g., penta-BDE can refer to either the technical mixture called “Penta” or could refer to a PBDE with 5 bromines  Commercial mixtures sometimes distinguished as “c- penta” PBDE naming - congeners BDE-99 Pentabromodiphenyl ether BDE-47 Tetrabromodiphenyl ether BDE-153 Hexabromodiphenyl ether BDE-154 Hexabromodiphenyl ether BDE-100 Pentabromodiphenyl ether BDE-183 Heptabromodiphenyl ether BDE-209 Decabromodiphenyl ether BDE-28 Tribromodiphenyl ether Polybrominated Diphenyl Ethers: Uses Penta Textiles, PUF, paint, household plastic products, automotive parts banned under Stockholm Convention Octa ABS plastic for computers, casings, circuit boards, small appliances banned under Stockholm Convention Deca Electrical & electronic equipment, casings for TVs, computers, textile backings (e.g., carpets) Still in use in some areas, phased out in Europe, North America Human health concerns for PBDEs  Thyroid active agents  Neurological impairments  Maturation  Delay in puberty  Developmental neurotoxicity  Impaired spontaneous motor behaviour, nonhabituation behaviour  Learning & memory  Worsen with age Review: Birnbaum & Staskal 2004 EHP 112:9-17. Estimated Historical Consumption Of Penta BDE in Europe Prevedouros et al. 2004 Environ Sci Technol 38:3224-3231 Estimated Consumption Of BDEs in North America Abbasi et al. 2015 Environ Sci Technol How to PBDEs get from furniture into the environment?  Volatilization  Abrasion, physical breakdown of the furniture  Direct partitioning to dust Global distributions of PCBs and PBDEs From Pozo et al. 2006 Hites 2004 Environmental Science & Technology Replacement of banned compounds Flame retardancy standards remain Need for new compounds to meet flame retardancy standards “Novel” brominated and chlorinated flame retardants Unknown properties, effects ???? 2000-2015: Banning/ phasing out of PBDEs “Novel” flame retardants - NFRs – replacements for PBDEs Br Br Br BrBr Br Br Br BrBr O CH3 CH3 O Br Br Br Br Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl O O BrBr Br Br Br Br Br Br Br Br Br Br Br Br Br Br Br CH3 Br Br Br Br Br CH3 Br Br Br Br HBB DDC-CO DBDPE BTBPE DBE-DBCHEH-TBB PBEB PBT Phosphate- based flame retardants in consumer products Stapleton et al. Environmental Science and Technology, 2009 Plasticizers - Phthalate esters  One of the most broadly uses classes of synthetic compounds  1-2 million tonnes per year  Plasticizers – increase material flexibility and transparency  Up to 60% by weight of material  Wide range of uses: vinyl building and construction materials (e.g: flooring, wall coverings, piping), adhesives, sealants, printing inks, paints, and medical applications (eg: blood storage bags), wood finishes, detergents, adhesives, plastic plumbing pipes, lubricants, solvents, insecticides, cosmetics and personal care products, including perfume, hair spray, soap, shampoo, nail polish, and skin moisturizers Phthalate exposure  Through eating, drinking foods that were in contact with phthalate-containing plastics  Use of personal care products containing phthalates (dermal absorption)  Inhaling air or ingesting dust containing phthalates 0 1 10 100 1000 Medianconc.(μg/g) Median conc. in settled dust (μg/g) 0 1 10 100 1000 Medianconc.(ng/m3) Median conc. in indoor air (ng/m3) Phthalates • Usually the highest concentration synthetic compound found in indoor dust and air • Levels typically 10-100x higher than other SVOCs Dust and air samples from 30 homes, Western France1: 1 Blanchard et al. 2014 Environ Sci Tech Phthalates exposure Health risks of phthalates  Reproductive effects, especially in men  Associated with diabetes in women (James-Todd et al., Environmental health perspectives, 2012)  Occurrence of asthma and allergies in children (Jaakkola and Knight, Environmental health perspectives, 2010)  Autism spectrum disorders (Kalkbrenner et al. Current Problems in Pediatric and Adolescent Health Care, 2014) Current regulatory status EU REACH Legislation DHP – reproductive toxin DEHP – serious effects on environment DEHP, DBP, BBP, DIBP – serious effects on human health DEHP, DBP, BBP – should have been banned in EU this year (February 2015)... But... “This ban will only cover these substances when they are: - Supplied on their own; - Supplied in a mixture; - Incorporated into an article with the European Union. Imported articles containing any of these substances that were incorporated outside the EU are not covered by the Authorisation process.” Chemicals to know  Particulate matter  DDT  PCBs  PCDD/Fs  PAHs  PBDEs  phthalates What to know… ABOUT EACH COMPOUND:  What is the source/use of the compound  Industrial? Emission by-product?  General information about the structure (is it chlorinated or brominated, is it just one compound or is it a group of compounds…?)  Status  Is the chemical still in use? Where is it legal/illegal?  Where do we find the chemical?  In the environment? In humans? How and where are humans exposed?