Changha Lee
School of Chemical and Biological Engineering Seoul National University
http://artlab.re.kr 고도산화환원 환경공학 연구실
Advanced Redox Technology (ART) Lab
Water Pollution-2
-Water Pollutants
History of Pollution and Drinking Water Quality Regulation in Korea
CAS (Chemical Abstracts Service)에 등록된 화학물질 5천5백만 종
전세계적으로 대량 유통되는 화합물 10만여 종
1980 1985 1990 1995 2000 2005 2010 2015
2002년: 55개 항목
• 분원성대장균군, 유리잔류염소, chloral hydrate, dibromoacetonitrile, dichloroacetonitrile, trichloroacetonitrile, haloacetic acid, 1,2-dibromo-3-chloropropane
1992년: 37개 항목
• Carbaryl, trichloroethylene, perchloroethylene, 1,1,1-trichloroethane
1994년: 43개 항목
• Al, BTEX (benzene, toluene, ethylbenzene, xylene),
dichloromethane, tetrachloromethane
1996년: 45개 항목
• 1,1-dichloroethylene
2009년: 57개 항목
• Dibromochloromethane, bromochloromethane
2011년: 58개 항목
• 1,4-dioxane 2014년: 59개 항목
• HCHO
2017년: 60개 항목
• Bromate 1990년: 29개 항목
• Trihalomethanes
1991년: 33개 항목
• Diazinon, parathion, malathion, fenitrothion
1984년: 28개 항목 2000년: 47개 항목
• B, chloroform
우리나라 먹는물 수질기준 60개 항목(2017년 기준)
1990년: 정수장 THMs 검출사건
1991년: 낙동강 페놀오염사건 1994년: 낙동강 수질오염사고
2001년: 수돗물 바이러스 검출사고
2005년: 섬진강 농약 오염사건
2009년~: 낙동강 1,4-Dioxane 오염사건
Common Water Pollutants
√ 8 classes of water pollutants of interest
1. Pathogens 2. Nutrients 3. Salts
4. Thermal Pollution 5. Heavy Metals 6. Pesticides
7. Volatile Organic Compounds (VOCs) 8. Oxygen Demanding Waste
Pathogens
• Disease producing organisms that grow and multiply within a host
Bacteria: cholera, dysentery, typhoid
Viruses: infectious hepatitis, poliomyelitis
Protozoa: amebic dysentery, giardiasis
Helminths (parasitic worms): schistosomiasis
• Spread of disease: sewage contaminates drinking water.
e.g., Cholera epidemic of London in 1840’s
Typhoid/cholera epidemic of Chicago in 1885.
• Chlorination of water supplies in developed countries (including Korea) virtually eliminated these problems, but they are severe in many other parts of the world.
Pathogens
√ Two types of infection:
1. Water borne – acquired by ingesting pathogens by drinking water or contact through utensils, food, etc.
Contamination from open water handling system
In the U.S. Giardia and Cryptosporidium are problematic.
Cysts survive a long time and are not easily destroyed by chlorination, ozonation, radiation, etc.
2. Water contact – No need to drink the water, just be in it.
Schistosomiasis (affects 200M) – eggs develop in snails and attach to human skin, enter blood and mature in liver. Snails must have still water conditions.
Water breeding insects spread malaria, yellow fever,
lack of water for hygiene allows skin diseases to develop (leprosy, trachoma).
Pathogens
• Leading causes of death worldwide (1994)
Pathogens
• Emerging infectious diseases (2003)
Importance of Clean Water (Disinfection)
√ Waterborne illnesses was major
cause of death
Nutrients
• Nutrients are chemicals essential for life but are problematic when there high concentrations allow for excessive aquatic plants, especially algae.
Main concern is Eutrophication
When algae decay they create excessive oxygen depletion
• 3 Important nutrients – C, N, P
Lack of one of these three limits plant growth
• Carbon is available from the atmosphere (CO2)
Seawater limited by N, fresh water limited by P
• Nitrogen and phosphorus are in:
Wastewater
Feedlot runoff
Agricultural chemicals
• Nitrites are dangerous to babies: methemoglobinemia
(also called blue-baby syndrome – caused by chemical asphyxiation)
Nutrients
Salts
• Many salts naturally accumulate in water
Na+, Ca2+, Mg2+, K+, Cl–, SO42–, HCO3–
A rough measurement of salt content is the total dissolved solids (TDS)
1.5 m pore size
TSS : Total Suspended Solids TDS : Total Dissolved Solids TS : Total Solids (=TSS + TDS) e.g., Solids
Salts
• Animals can tolerate more than 500 mg/L TDS
Type of water TDS (mg/L)
Fresh water < 1,500
Brackish water 5,000
Saline water > 5,000
Sea water 30,000 to 40,000
Drinking water < 500
• Irrigation requires less than 500 to 2,000 mg/L TDS
Thermal Pollution
• What are the effects of using water in a cooling system where the discharges are warmer than the input?
– This causes stress on aquatic life.
• Dissolved Oxygen (DO) is a function of temperature
• If temperature increases 10℃, DO can decrease by 20% and organisms metabolism and oxygen demand increases.
Heavy Metals
• Group of metals with high density (>4 or 5 g/cm3)
Most are toxic.
• Examples: lead (Pb), cadmium (Cd), high doses of hexavalent chromium (Cr6+), mercury (Hg2+),
• These compounds are absorbed by the body with varying effects on the nervous system, kidneys…
Pesticides
• Include insecticides, herbicides, rodenticides, fungicides.
• They are problematic because they are persistent They are designed to last, and don’t react.
• Lipophilic (soluble in fat) – accumulate in animal’s fatty tissue (bioaccumulation) and through the food chain (biomagnification).
• Organochlorides (early pesticides) – many are toxic to humans (e.g., DDT, lindane, dieldrin) now replaced with organophosphates and carbamate.
• Organophosphates are not as persistent, but are more toxic – absorbed through the skin, lungs, intestines
• Carbamates have some side effects at acute exposures
Pesticides
• 95% of pesticides could cause cancer!!!
• Babies and young children may have poor brain development
VOCs (Volatile Organic Compounds)
• Most common ground water pollutants (e.g. BTEX)
Many are used as solvents and are carcinogens
• Vinyl chloride (chloroethylene) – making PVC resins, also carcinogen
• Tetracholorethylene (PCE) – solvent and CFC production
• Trichloroethylene (TCE) – solvent and suspected human carcinogen
• 1,2-dichloroethane (DCA) – metal degreasing, high exposure causes kidney, liver, CNS damage – very soluble
• Carbon tetrachloride (CT) – household cleaning, fungicide, very toxic .
Banned by the Montreal protocol in 1995
Oxygen Demanding Wastes
• Oxygen dissolved in water (DO) is important for many forms of aquatic life.
• From Henry’s Law, the DO concentration in air-saturated water is 8 to 15 mg/L depending on temperature and salinity.
• Fish need 3 mg/L (carp) to 5-8 mg/L (trout)
• Biodegradation of organic waste from wastewater (sewage) and industrial
effluents create an oxygen demand, as do natural organics and animal wastes.
• As DO falls, odors, taste, colors make water less acceptable.
• COD – oxygen required for chemical oxidation
• BOD – biochemical oxygen demand – oxygen required by microorganisms to biologically degrade (stabilize) organic wastes.
Water Treatment Objectives and Priorities
Adapted from: Coffey and Reid (1982)
UNEP POPs List (Dirty Dozen)
Dioxins
Furans
PCBs
HCB
DDT
Chlordane
Toxaphene
Dieldrin
Aldrin
Endrin
Heptachlor
Mirex
• Dirty dozen (Stockholm Convention),
a group of twelve Persistent organic pollutants (POPs)
Selected Emerging Pollutant Classes
• Endocrine disrupting compounds
Pharmaceuticals & cosmetics that bioaccumulate and affect reproduction (PFOs, synthetic musk fragrances, PBDEs)
• Oxidized energetics and rocket propellants
Carcinogens such as NDMA, perchlorate, RDX
• Small ethers
Solvent stabilizers (1,4-dioxane) or gasoline oxygenates (MTBE), which are also suspected carcinogens.
• Waste nanomaterials
Growing industry with materials that bioaccumulate or co-transport pollutants (e.g., Titania, C-nanotubes, nano-silver)
• Biological agents
Calcivirus, prions, antibiotic resistance genes
Emerging Pollutants
pesticides
atrazine,
simazine, diuron, bentazone,
glyphosate
human/
veterinary drugs
industrial chemicals
NTA, EDTA bisphenol A,
nonylphenol phthalates natural hormones
estradiol, ß -sitosterol
endocrine disruptors
DDT, lindane, amitrole, vinclozolin synthetic
hormones ethinyl- estradiol analgesics,
lipid-lowering agents, beta-
blockers, antibiotics
EDCs: Sulfonated Perfluorochemicals
• Building blocks of 3M’s perfluorinated surfactants – Scotchgard (3,000 tons in 2000)
• Persistent: C-F is a very strong bond (110 kcal/mol)
• Concerns: bioaccumulation, interference with mitochondrial bioenergentics and biogenesis, increase in liver size, endocrine disruption, acute aquatic toxicity.
• 3M recently removed the product line from market.
EDCs: Synthetic Musk Fragrances
• Semi-volatile: for perfumes, cosmetics, soaps, shampoos, detergents.
• Released by down-the-drain disposal of consumer products.
• Atmospheric distribution and deposition is also important.
• Concern: bioaccumulation (little is known about their health effects).
Polybrominated Diphenyl Ethers
• Used in electronics, plastics, car upholstery, furniture, and cables.
• Flame retardants (saves lives! ☺ and $11 billion/year in damages in the US)
• Concerns: persistence, bioaccumulation (found in fish tissue, marine wildlife, pg/m3 in human blood, milk).
• The new PCBs (atmospheric distribution and deposition is also important).
Unique Properties of Nanomaterials
• Chemical reactivity greatly different from macroscopic forms
e.g., Au becomes catalytic, insulators such as silicon and carbon become conducting, and opaque materials such as TiO2 become transparent
• High surface area per unit mass (>100 m2/g)
• Quantum effects (dual behavior, wave- and particle-like) resulting in unique mechanical, electronic, photonic, and magnetic properties
• More than 1,600 Commercial products contain nanomaterials worldwide.
• $1 trillion market, sensors, electronics, drug delivery, tissue engineering, imaging, catalysis, cosmetics, sunscreens, etc.
54
356 380
803
1015
1317
1628
0 200 400 600 800 1000 1200 1400 1600 1800
2005 2006 2007 2008 2009 2010 2013
Number of Products
Year
http://www.nanotechproject.org/cpi/about/analysis/
Nano-products on the Market
Nano-products on the Market
Display Screens Motorola (NTs)
Nano Silver Wash
Samsung Washing Machine
(Actually it was not nano Ag, No more production)
Tennis Rackets Wilson (C fibers) Automobiles
(BASF’s Mincor® Nanocomposite)
Sunscreen
(TiO2 )
Responsible Nanotechnology
30
"With Great Power, Comes Great Responsibility"
-Uncle Ben to Peter Parker in Spider Man
Nanoscale fibers on spider feet
(Dr. Nigel Walker, NIEHS NTP)
Cell Toxicity Mechanisms of Nanomaterials
Disruption of membrane/ cell wall by
carboxyfullerene
DNA damage
ROS
Protein oxidation
e-
e-
Release of toxic ions
by QDs, nano-silver, nZnO
Generation of Reactive Oxygen Species by TiO2
& aminofullerenes
Ag+ Cd2+ Zn2+
Interruption of respiration and protein oxidation upon contact (e.g., nC60 , CeO2)
Common Challenges for Emerging Pollutants
• Structural information and standards for their analysis are very difficult to obtain (intellectual property).
• Too many chemicals (e.g., 2100 synthetic fragrances), not enough
information or research on their effects, especially for chronic toxicity and ecological impacts.
• Different exposure pathways – we ingest pharmaceuticals, spray
insecticides in the air, apply fragrances and we sit on couches that have both brominated flame retardant and perfluorinated surfactant protectants.