United States
Environmental Protection
Agency
Office of Water
4601
EPA 8T1-F-95-002C-T
October 1995
oEPA
National Primary Drinking
Water Regulations
Cadmium
CHEMICAL/PHYSICAL PROPERTIES
CAS NUMBER: 7440-43-9 (metal)
COLOR/ FORM/ODOR: Cadmium, is a lustrous silvery metallic
element found only in combined forms in nature.
SOIL SORPTION COEFFICIENT: Koc = N/A; mobility higher than other
metals .
BIOCONCENTRATION FACTOR: Fish: 33 to 2213; Shell fish: 5 to 2500;
Other invertebrates: 164 to 4190; Plants: 603 to 960.
COMMON ORES: sulfide- greenockite; carbonate- octavite; others:
hawleyite. Also found in zinc, copper, lead ores.
SOLUBILITIES (WATER):
acetate- very soluble
bromide- 570 g/L at 10 deg C
carbonate- insoluble
chloride- 1400 g/L at 20 deg C
fluoroborate- very soluble
mercury sulfide- N/A
nitrate- 1090 g/L at 0 deg C
oxide- insoluble
sulfate- 755 g/L at 0 deg C
sulfide- insoluble
stearate- N/A
DRINKING WATER STANDARDS
MCLG: 0.005 mg/l
Met: 0.005 mg/l
HAL(child): 1-to 10-day: 0.04 mg/L
Longer-term: 0.005 mg/L
HEALTH EFFECTS SUMMARY
Acute: EPA has found cadmium to potentially cause a
variety of effects from acute exposures, including: nau-
sea, vomiting, diarrhea, muscle cramps, salivation, sen-
sory disturbances, liver injury, convulsions, shock and
renal failure.
Drinking water levels which are considered "safe" for
short-term exposures: For a 10-kg (22 Ib!) child consum-
ing 1 liter of water per day, a one-to ten-day exposure to
0.04 mg/L; a longer-term (up .to 7 years) exposure to
0.005 mg/L.
Chronic: Cadmium has the potential to cause
kidney, liver, bone and blood damage from long- term
exposure at levels above the MCL
Cancer: "There is inadequate evidence to state whether
or not cadmium has the potential to cause cancer from
lifetime exposures in drinking water.
USAGE PATTERNS
2.9 million IDS of cadmium were produced in the US in
1986, and nearly twice that amount was imported in the
Same year.
According to 1986 estimates, cadmium is used prima-
rily for metal plating and coating operations (35%),
including transportation equipment, machinery and bak-
ing enamels, photography, television phosphors. It is
also used in nickel-cadmium and solar batteries (25%), in
pigments (20%), as a stabilizer in plastics and synthetic
products (15%), alloys.and other uses (5%). Cadmium
salts have had a very limited use as fungicide for golf
courses and home lawns.
RELEASE PATTERNS
. • • i -j
Cadmium occurs naturally in zinc, lead and copper
ores, in coal and other fossil fuels, shales and is released
Toxic RELEASE INVENTORY •
RELEASES TO WATER AND LAND:
1987 TO 1993
Water
TOTALS (in pounds) 31,487
Top Seven States *
AZ 503
UT 1.750
MT 0
TN 2,700
ID 250
MO 2,361
Wl 0
Major Industries*
Zinc, lead smelting 5,061
Copper smelting, refining 2,253
Indust. inorganic chems 250
Electroplating, anodizing .0
Steelworks, blast furnaces 5
Inorganic pigments 5,140
Land
2,059,574
433,035
372.010
315,965
288,781
225,761
189,914
106,000
831.948
805.045
225,761
106,000
13,000
7,000
* State/Industry totals only include facilities with releases
greater than a certain amount - usually 1000 to 10,000 Ibs.
October 1995
Technical Version
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during volcanic action. These deposits can serve as were controlled by the nature of total heavy metal load-
sources to ground and surface waters, especially when ing, the sediment type, and the surface water character-
in contact with soft, acidic waters, istics.
Major industrial releases of cadmium are due to wast-
estreams and leaching of landfills, and from a variety of
operations that involve cadmium or zinc. Ttese may
include: during the smelting and refining of zi lead and
copper bearing ores; during recovery of mi al by pro-
cessing scrap; during melting and pouring of cadmium
metal; during casting of various cadmium alloy products
used for coating telephone cables, trolley wires, welding,
electrodes, automatic sprinkling systems, steam boilers,
fire alarms, high pressure/temperature bearings, starting
switches, aircraft relays, light duty circuit breakers, low
temperature solder, and jewelry; during fabrication of
metal, alloys, or plated steel; during casting and use of
solders; during melting of cadmium ingots for paint and
pigment manufacture used for coloring of plastics and
ceramic glazes, electroplating, and in chemical synthe-
sis; during coating of metals by hot dipping or spraying;
during manufacture of nickel-cadmium batteries for use
in radio portable telephones, convenience appliances,
and vented cells used in airplanes, helicopters, and
stand-by power and lighting. The remaining cadmium
emissions are from fossil fuel combustion, fertilizer appli-
cation, and sewage sludge disposal.
Cadmium also occurs as a by-product of corrosion of
some galvanized plumbing and distribution system ma-
terials.
From 1987 to 1993, according to EPA's Toxic Chemi-
cal Release Inventory, cadmium releases were primarily
from zinc, lead and copper smelting and refining indus-
tries, with the largest releases occurring in Arizona and
Utah.
ENVIRONMENTAL FATE
The oxide and sulfide are relatively insoluble while the
chloride and sulfate salts are soluble. The adsorption of
cadmium onto soils and silicon or aluminum oxides is
strongly pH-dependent, increasing as conditions be-
come more alkaline. When the pH is below 6-7, cadmium
is desorbed from these materials. Cadmium has consid-
erably less affinity for the absorbents tested than do
copper, zinc, and lead and might be expected to be more
mobile in the environment than these materials.
Studies have indicated that cadmium concentrations
in bed sediments are generally at least an order of
magnitude higher than in overlying water. A study of
Ottawa River sediments found that sediment composed
mainly of well sorted sand may be an efficient sink for
heavy metals if there is a significant amount of organic
material added to the sediments by the commercial
activities such as logging. Both sorption and desorption
Addition of anions, such as humate, tartrate, to dis-
solved cadmium caused an increase in adsorption. The
mode by which cadmium is sorted to the sediments is
important in determining its disposition toward remobili-
zation.
Cadmium found in association with carbonate miner-
als, precipitated as stable solid compounds, or co-pre-
cipitated with hydrous iron oxides would be less likely to
be mobilized by resuspension of sediments or biological
activity. Cadmium absorbed to mineral surfaces (eg clay)
or organic materials would be more easily bioaccumu-
lated or released in the dissolved state when sediments
are disturbed, such as during flooding.
Cadmium is not known to form volatile compounds in
the aquatic environment.
Bioconcentration of cadmium sulfate, nitrate and chlo-
ride has been studied in a wide variety of aquatic organ-
isms, and can be quite high in some species, low in
others. For example, rainbow trout have a BCF of 33
while a BCF of 2213 was measured in the mosquito fish.
Similarly, different species of clams have BCFs ranging
from 160 to 3770.
OTHER REGULATORY INFORMATION
MONITORING:
- FOR GROUND WATER SOURCES: '
INITIAL FREQUENCY- 1 sample once every 3 years
REPEAT FREQUENCY- If no detections for 3 rounds, once every 9 years
- FOR SURFACE WATER SOURCES:
INITIAL FREQUENCY- 1 sample annually
REPEATFREQUENCY- If no detections for 3 rounds, once every 9 years
- TRIGGERS - If detect at > 0.005 rhg/L, sample quarterly.
ANALYSIS:
REFERENCE SOURCE
EPA 600/4-79-020
NTIS PB 91-231498
Standard Methods
METHODNUMBERS
213.2
200.7
3113B
TREATMENT
BEST AVAILABLE TECHNOLOGIES
Coagulation/Filtration, Ion Exchange, Lime Softening, Reverse Osmosis
FOR ADDITIONAL INFORMATION:
A EPA can provide further regulatory and other general information:
• EPA Safe Drinking Water Hotline - 800/426-4791
* Other sources of toxicologies! and environmental fate data include:
• Toxic Substance Control Act Information Line - 202/554-1404
• Toxics Release Inventory, National Library of Medicine - 301/496-6531
• Agency for Toxic Substances and Disease Registry - 404/639-6000
October 1995
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