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Organic SolventsFriend or Foe?
Mary F. McDaniel, DO, JD, MPHMcDaniel Lambert, Inc.
May 31, 2005
What are organic solvents?
Organic solvents Organic - contain carbon and hydrogen Low molecular weight Lipophiolic (“fat-loving”) Volatile (evaporates readily) Liquid at room temperature
Used in a wide range of industries and essential to many manufacturing processes
Solvents dissolve fats and greases and other materials (rubber, plastic, etc.,) Predominantly used as cleaners and degreasers
Other uses include controlling viscosity and drying rates, and as raw materials in other products Thinner/mixer for pigments, paints, glues,
pesticides, and epoxy resins
How are people exposed to solvents?
Occupational exposure Inhalation of vapors Dermal contact - solvents penetrate the skin and pass into the
blood
Environmental exposure Living near industrial producers or users Use of household cleaning products, paints, etc. Exposure to contaminated water, soil, air, or food
Recreational “drug” use Inhalation of paints, glues, and other products
What are the general effects of solvent exposure?
Potential for acute and chronic effects including Reversible and nonreversible abnormalities in the
central and peripheral nervous systems Damage to the liver, kidneys, lungs
Factors influencing effects Solvent type Amount Duration of exposure
Indoor Air - Vapor Intrusion
Volatile chemicals in contaminated soil or groundwater can migrate through subsurface soils and into indoor air spaces of overlying buildings
Love Canal
70-acre industrial landfill located in Niagara Falls, New York
Landfill originally a canal excavated in the 1890s for an unfinished hydroelectric project
From 1942 - 1952, Hooker Chemicals and Plastics (Occidental Chemical Corporation) disposed of 21,000 tons of hazardous wastes in the canal – including solvents
Love Canal
Despite the desire of Hooker Chemical for the site to be used only for open space, the area was eventually covered and the property developed…including the construction of an elementary school
Included in the deed transfer was a "warning" of the chemical wastes buried on the property and a disclaimer absolving Hooker of any further liability
Complaints of odors and chemical residues begin in the 1960’s, increased in the 1970’s as heavy rainfall caused the groundwater to rise, flooding area basements
Love Canal – Spring 1978
2 rings of homes border landfill
99th Street Elementary School
White patches indicate areas without vegetation – leaching?
Love Canal
May 1978 - EPA concluded from basement air sampling that vapors are a serious health threat
August 1978 – President Jimmy Carter declared the Love Canal area a federal emergency
More than 900 families were forced to leave their homes
Site publicity directly spurred passage of EPA’s Superfund law in 1980
December 1995 - Occidental ordered to pay $129 million settlement
Residents returned to portions of the site in late 1990’s Epidemiological study into potential health effects ongoing
General Solvent Types
Chlorinated Solvents - widely used in cleaning and degreasing trichloroethylene (TCE), 1,1,1-trichloroethane (TCA),
tetrachloroethylene (PCE), carbon tetrachloride, etc.
Petroleum Distillates - primarily used as fuels, but also used as cleaning agents Petroleum naphthas and petroleum ethers are typically used
as solvents - Stoddard solvent, mineral spirits
Other Synthetic Organic Chemicals – pesticides, PCBs, etc.
Industrial Solvent Uses
INDUSTRY USAGE SOLVENT TYPE
Adhesives • component cleaning agent
• aliphatic or chlorinated hydrocarbons
Antifreeze • component • glycols
Chemical and pharmaceutical industry
• used for chemical reactions
• a range of solvents
Dry cleaning • cleaning agent • chlorinated solvents
Engineering industry • degreasing metal and plastic surfaces
de-watering
• trichlorothylene isopropanol
Paints, printing inks • component cleaning agent
• hydrocarbons (e.g. white spirit)
xylene toluene
Chlorinated Solvents
Carbon tetrachloride - first chlorinated solvent to come into general use (early 1900s) First widespread uses were household cleaning agent and a fire
extinguishing fluid Some medicinal use as a hookworm treatment in animals and,
primarily in tropical regions, in humans In 1929 DuPont and General Motors produced the first
chloroflourocarbons (CFCs) using "Freon“; production and use now prohibited
Tetrachloroethylene - widely known as a dry-cleaning solvent Was used in cleaning and degreasing in various textile production
processes Was used in the production of fluorinated compounds such as
CFC-113
TCE - trichloroethylene
Major environmental releases Air emissions from industrial
degreasers Industrial wastewater
OSHA exposure limit 100 ppm in air (8-hour day/40-hour
week)
US EPA drinking water limit and CA MCL 5 ppb
TCE Health Effects
Acute exposure to TCE in air: CNS effects - Dizziness, headache, lightheadedness Eye, nose, and throat irritation Nausea and vomiting Exposure to large amounts may cause heart problems
such as cardiac arrhythmias
Chronic exposure: Nerve, kidney, and liver damage Animals – increased liver, lung, and kidney tumors Humans – probable carcinogen
TCE Monitoring
Recent exposure Breath, blood, and urine tests
Up to a week following exposure blood and urine test for TCE and metabolites
Some metabolites may result from exposure to other similar chemicals – so not absolute proof of TCE exposure
Perchlorate – not a solvent, but…
Naturally occurring and manmade inorganic contaminant increasingly found in groundwater, surface water, and soil
Mostly used as an ingredient in solid fuel for rockets and missiles
Other products - safety flares, aluminum refining, electroplating, and the production of paints
Perchlorate Health Effects
Primary health concern is the interference with the uptake of iodide, an essential nutrient, by the thyroid gland Inadequate iodide uptake may lead to the harmful disruption
of proper thyroid function
In the 1950s perchlorate was approved by the U.S. FDA to treat people with overactive thyroid glands
Perchlorate in drinking water
Perchlorate contamination reported in at least 20 states
As of May 2005, detected in 375 California drinking water supplies at concentrations ranging from 3.3 to 820 ppb
California Public Health Goal – 6 ppb
245 ppb
6 ppb
24.5 ppb
No effect dose (NOEL) from human volunteer study identified by National Academy of Sciences (NAS)
Safe drinking water level based on safe dose recommended by NAS (0.0007 mg/kg/day)•Includes additional safety factor to protect most sensitive group – the fetus•U.S. EPA Drinking Water Equivalent Level
Perchlorate Drinking Water Levels & Safety Factors
CA Public Health Goal/Notification Level•Assumes people also ingest perchlorate from food (so less allowed in water)•Based on same NAS no effect dose, but lower statistical value