FACT SHEET ON A DRINKING WATER CHEMICAL CONTAMINANT
GENERAL INFORMATION
Synonyms
•	Xylols; Dimethyl benzene
Chemical Description:
•	Mixture of the three isomers of xylene (ortho,
mefa and para)
Properties:
•	Clear, colorless, flammable liquid at room
temperature
•	Moderate vapor pressure
•	Moderately soluble in water
Production and Us®:
•	Occur naturally as a component of petroleum
oil, and as a by-product of gasoline refining
•	Used:
•	as solvents for paints, lacquers, varnishes,
inks, dyes, and adhesives
•	as a component of detergents
•	in the manufacture of quartz crystal
oscillators, perfumes, and insect repellents
ENVIRONMENTAL PROFILE
Occurrence:
•	tow-level contaminant of both ground and
surface public water supplies
•	EFA's Community Water Supply Survey found
that 3% of all ground water derived, and 6% of
all surface water derived public drinking water
systems sampled had levels greater than
0.0005 mg/l
Releases:
•	Releases to the environment are largely to air
due to its volatile nature, with smaller amounts
to soil and wafer
•	Releases to water are due to spills and leaks of
gasoline and other petroleum products, and
from the' disposal of waste from paints, inks,
and other industrial products
Environmental Fats:
•	Released to soil: will volatilize rapidly on soli
surface, with volatilization rate decreasing with
increasing soil depth; will bind somewhat to
soils; may chemically and biologically degrade
during passage through soil to groundwater
•	Released to surface water?: will volatilize *a:riy
rapidly (dominant removal process) to -he
atmosphere where they will photodegrade
rapidly; some adsorbtion to sediment will
occur; once present in ground wafer, they are
not likely to degrade, and may persist for
months or years
HEALTH EFFECTS
Humans:
» Inhalation studies have shown that xylenes
produce disturbances in the central nervous
sytem (CNS) as reflected in changes in
numerative ability, short-term memory, body
balance, reaction time, and manual
coordination
Experimental Animais:
•	Long-term, high dose exposure by inhalation
causes detrimental effects upon the CNS, liver,
and kidney functions
•	Inconclusive studies on the fetotoxicity and
teratogenicity of xylenes
•	No evidence of carcinogenic potential
REGULATORY PROFILE
Existing Regulations:
•Clean Air Act (CAA): Not regulated
•Clean Water Act (CWA):
No criteria established
•Resource Conservation and Recovery Act
(RCRA):
Hazardous waste
•Superfund (CERCLA):
• Hazardous substance
•SARA: Toxic chemical
•	Federal insecticide, Fungicide, and
Rodenttclde Act (FIFRA):
Registered
•	Toxic Substances Control Act (TSCA):
Regulated

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HEALTH INFORMATION
Maximum Contaminant Level Goals (MCLG):
•	Non-enforceable levels based solely on an
evaluation of possible health risks and
exposure, and taking into consideration a
margin for public safety
•	Set at 10 mg/l to protect against damage to
the liver, kidneys, and nervous system
MCLG for Xylenes = 10 mg/l
(effective July 1992)
Maximum Contaminant Levels (MCI):
•	legally enforceable levels for contaminants in
public drinking wafer supplies
•	Based on health risks associated with the
contaminants, analytical methods for their
assay, and water treatment feasibility and
practicality aspects
« Exceedance of the MCI in drinking water may
result in adverse effects which will depend
upon the contaminant concentration in water,
amount of water/contaminant ingested,
length of exposure, and other biological
parameters
MCL for Xylenes = 10 mg/L
(effective July 1992)
EPA Health Advisories (HA):
•	Short-term HAs: Provide acceptable
concentrations of contaminants in water for
uo to 10 day exposures, primarily to evaluate
the public health risk resulting from an
accidental spill or an emergency
contamination situation
•	Longer-term HAs: Provide guidance for
persistent wafer contamination situations to
cover a period of up to 7 years
•	Lifetime HAs: Derived in the same way as an
MCLG
Heolffo Advisories:
•	Purge and Trap Column Gas Chromafogrocr ^
with Photoionization and S.-ec'rciv'-c
Conductivity Detectors in Series:
EPA Method 502.2
•	Purged Column Gas Chromatography/Mass
Spectrometry:
EPA Method 524.1
•	Capillary Column Gas Chromatography/Mass
Spectrometry:
EPA Method 524.2
WATER TREATMENT
Permanent Treatment:
•	Best Available Technology (BAT):
« Granular Activated Carbon
*	Packed Tower Aeration
SHORT-TERM HAZARD ELIMINATION
» If the drinking water standards are exceeded,
install BAT or use an alternative drinking water
supply such as bottled water
ADDITIONAL HELP
•	-State or county health officials can indicate a
certified laboratory for testing
•	Experts in the state Department of
Environmental Protection or Natural Resources
may also be of help
•	The EPA has toll-free numbers for further
information on drinking water quality,
treatment technologies, for obtaining Health
Advisories, and for other regulatory information
•	EPA Hotlines are available Monday through
Friday
•	Safe Drinking Water.	800-426-4791
•National Pesticides: 800-858-7376
~Superfund/RCRA: 800-424-9346
•	For information on the Clean Water Act, call
(202) 260-7301
•	For information on the Toxic Substances
Control Act, call (202) 554-1404
•	For information on the Clean Air Act, call
(919) 541-2777
Short-term HA for a child * 40 mg/l
Longer-term HA for a child * 40 mg/L
Longer-term HA for an adult = 100 mg/l
Lifetime HA = 10 mg/l
ANALYTICAL METHODS'
« Purge and Trap Gas Chromatography:
EPA Method 502.1
EPA Method 503.1

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