ENVIRONMENTAL CONTAMINANTS ENCYCLOPEDIA

CADMIUM ENTRY

July 1, 1997

COMPILERS/EDITORS: 

ROY J. IRWIN, NATIONAL PARK SERVICE

WITH ASSISTANCE FROM COLORADO STATE UNIVERSITY

STUDENT ASSISTANT CONTAMINANTS SPECIALISTS:

MARK VAN MOUWERIK

LYNETTE STEVENS

MARION DUBLER SEESE

WENDY BASHAM

NATIONAL PARK SERVICE 

WATER RESOURCES DIVISIONS, WATER OPERATIONS BRANCH

1201 Oakridge Drive, Suite 250

FORT COLLINS, COLORADO 80525 
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This document was put together by human beings, mostly by

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mistakes and/or potential misinterpretations and should

be used primarily as a way to search quickly for basic

information and information sources. It should not be

viewed as an exhaustive, "last-word" source for critical

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information). For critical applications (such as

litigation applications), it is best to use this document

to find sources, and then to obtain the original

documents and/or talk to the authors before depending too

heavily on a particular piece of information.

Like a library or most large databases (such as EPA's

national STORET water quality database), this document

contains information of variable quality from very

diverse sources. In compiling this document, mistakes

were found in peer reviewed journal articles, as well as

in databases with relatively elaborate quality control

mechanisms [366,649,940]. A few of these were caught

and marked with a "[sic]" notation, but undoubtedly

others slipped through. The [sic] notation was inserted

by the editors to indicate information or spelling that

seemed wrong or misleading, but which was nevertheless

cited verbatim rather than arbitrarily changing what the

author said.

 

Most likely additional transcription errors and typos

have been added in some of our efforts. Furthermore,

with such complex subject matter, it is not always easy

to determine what is correct and what is incorrect,

especially with the "experts" often disagreeing. It is

not uncommon in scientific research for two different

researchers to come up with different results which lead

them to different conclusions. In compiling the

Encyclopedia, the editors did not try to resolve such

conflicts, but rather simply reported it all.
It should be kept in mind that data comparability is a

major problem in environmental toxicology since

laboratory and field methods are constantly changing and

since there are so many different "standard methods"

published by EPA, other federal agencies, state agencies,

and various private groups. What some laboratory and

field investigators actually do for standard operating

practice is often a unique combination of various

standard protocols and impromptu "improvements." In

fact, the interagency task force on water methods

concluded that [1014]:

It is the exception rather than the rule that

water-quality monitoring data from different

programs or time periods can be compared on a

scientifically sound basis, and that...

No nationally accepted standard definitions exist

for water quality parameters. The different

organizations may collect data using identical or

standard methods, but identify them by different

names, or use the same names for data collected by

different methods [1014].

Differences in field and laboratory methods arre also

major issues related to (the lack of) data comparability

from media other than water: soil, sediments, tissues,

and air. 

In spite of numerous problems and complexities, knowledge

is often power in decisions related to chemical

contamination. It is therefore often helpful to be aware

of a broad universe of conflicting results or conflicting

expert opinions rather than having a portion of this

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Frequently one wants to know of the existence of

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a particular application. Many would like to see a high

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themselves what to throw out, partly because they don't

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criteria, and decided not to use it for this

application." This is especially true for users near the

end of long decision processes, such as hazardous site

cleanups, lengthy ecological risk assessments, or complex

natural resource damage assessments.

For some categories, the editors found no information and

inserted the phrase "no information found." This does

not necessarily mean that no information exists; it
simply means that during our efforts, the editors found

none. For many topics, there is probably information

"out there" that is not in the Encyclopedia. The more

time that passes without encyclopedia updates (none are

planned at the moment), the more true this statement will

become. Still, the Encyclopedia is unique in that it

contains broad ecotoxicology information from more

sources than many other reference documents. No updates

of this document are currently planned. However, it is

hoped that most of the information in the encyclopedia

will be useful for some time to come even with out

updates, just as one can still find information in the

1972 EPA Blue Book [12] that does not seem well

summarized anywhere else. 

Although the editors of this document have done their

best in the limited time available to insure accuracy of

quotes as being "what the original author said," the

proposed interagency funding of a bigger project with

more elaborate peer review and quality control steps

never materialized. 

The bottom line: The editors hope users find this

document useful, but don't expect or depend on

perfection herein. Neither the U.S. Government nor

the National Park Service make any claims that this

document is free of mistakes.

The following is one chemical topic entry (one file among

118). Before utilizing this entry, the reader is

strongly encouraged to read the README file (in this

subdirectory) for an introduction, an explanation of how

to use this document in general, an explanation of how to

search for power key section headings, an explanation of

the organization of each entry, an information quality

discussion, a discussion of copyright issues, and a

listing of other entries (other topics) covered. 

See the separate file entitled REFERENC for the identity

of numbered references in brackets. 

HOW TO CITE THIS DOCUMENT: As mentioned above, for

critical applications it is better to obtain and cite the

original publication after first verifying various data

quality assurance concerns. For more routine

applications, this document may be cited as:

Irwin, R.J., M. VanMouwerik, L. Stevens, M.D.

Seese, and W. Basham. 1997. Environmental

Contaminants Encyclopedia. National Park Service,

Water Resources Division, Fort Collins, Colorado.

Distributed within the Federal Government as an

Electronic Document (Projected public availability
on the internet or NTIS: 1998).
Cadmium (Cd, CAS number 7440-43-9)

Brief Introduction:

Br.Class: General Introduction and Classification Information:

The chemical element cadmium is a relatively rare, soft,

silver-white, transition element metal closely related to

zinc [333]. Its place in the periodic table is below zinc

and above mercury, and it has many properties in common

with these elements [333]. In nature, two oxidation

states are possible (0 and +2), however, the zero or

metallic state is rare [838]. Cadmium has no known

essential biological function [379,383]. However,

cadmium has been detected in more than 1000 species of

aquatic and terrestrial flora and fauna [379].

Cadmium enters the environment via three main routes:

refining and use of cadmium, copper and nickel smelting,

and fuel combustion [838]. The principal natural sources

of cadmium entering the atmosphere include windblown

transport of soil particles, forest fires, and volcanic

emissions. It is estimated that globally, anthropogenic

activities add roughly 3 to 10 times more cadmium into

the atmosphere than from natural sources; 56 to 85% of

this originates from the smelting of base metal ores

[907]. 

Cadmium acts as a cumulative poison [83] and is listed by

the Environmental Protection Agency as one of 129

priority pollutants [58,446]. Cadmium is also listed

among the 25 hazardous substances thought to pose the

most significant potential threat to human health at

priority superfund sites [93].

Br.Haz: General Hazard/Toxicity Summary:

Potential Effects to Fish, Wildlife, Invertebrates, and

other Non-Human Biota:

Cadmium is very toxic to a variety of species of

fish and wildlife. Cadmium causes behavior,

growth, and physiological problems in aquatic life

at sublethal concentrations [57]. Cadmium is the

only metal that clearly accumulates with increasing

age of the animal, and the kidneys are the

preferred site of cadmium accumulation [838]. 

Cadmium ions are extremely poisonous; their action

is similar to those of mercury [333]. All cadmium

compounds are potentially harmful or toxic [83]. 

It has been implicated in various deleterious
effects to fish and wildlife [379]. 

Immunosuppressive effects of cadmium have been

shown in mice [366], fish [982], and oysters [982].

Summary from chapter on cadmium in Sorensen's book

on metal poisoning in fish [488]:

Roughly, the toxicity of Cd in fish is

equivalent to that of Pb, but twenty-five

times less than that of Hg. Species-specific

variation is the rule. Cadmium-induced

toxicity is a function of water quality (e.g.,

salinity, water hardness, pH, alkalinity, and

temperature) and parasitism. Mucous

production, asphyxiation, inhibition of

acetylcholinesterase, depression of the

respiratory center, hypocalcemia, and gill

injury are causal factors in death, depending

on the species.

Cadmium is sometimes less toxic to freshwater

organisms in hard water than in softwater [838].

Humic acid or other complexing materials have a

varying effect on cadmium toxicity [838]. The

presence of complexing materials in water decreased

cadmium uptake and toxicity in fish, but had mixed

effects on toxicity to invertebrates. Monthly

tests demonstrated that cadmium toxicity in river

water varied by a factor of three or more over the

year due to fluctuating levels of suspended solids

[838].

The freshwater fish, Clarias batrachus, showed an

increase of the protein content in the liver,

kidney, stomach, intestine, testis, and ovary, and

a decrease in the muscle after copper and cadmium

treatment. The administration of copper and

cadmium increased the concentration of free amino

acids in all the fish organs (Jana S, Sahana SS;

Physiol Bohemoslov 37 (1): 79-82, 1988) [366].

Several comprehensive reports on the hazards of

cadmium are available. Cadmium hazards to fish and

wildlife are summarized in Eisler's 1985 synoptic

review [379]. The EPA published the Ambient Water

Quality Criteria for Cadmium (includes supporting

documentation) in 1984 [906]. A more recent

chapter on cadmium was published in 1991 as part of

Sorensen's book on metal poisoning in fish [488].

Environment Canada has prepared a priority

substances list assessment report for cadmium

[907]. Wren et al. provided a 1995 summary of

biological effects of mercury and cadmium [838].
Resistance/Development of Tolerance:

Populations of organisms chronically exposed

to chemical pollutants may develop increased

tolerance to those pollutants [177,493].

Increased synthesis of metallothionein (metalbinding proteins) in response to exposures to

various metals may help animals acquire a

somewhat increased tolerance to the metals

[180]. Cadmium exposure can induce metalbinding proteins (Denny Buckler, FWS Columbia,

personal communication). In this way, cadmium

is sequestered in metallothionein complexes

[838]. 

The metallothionein compounds have a high

proportion of sulfur-containing amino acids

that bind with cadmium such that it becomes

unavailable for interaction with intracellular

receptor sites. Tissue accumulation and

distribution of cadmium is dependent upon the

route of exposure (food or water vector)

[838]. Some of the aquatic issues related to

tolerance, interactions with other metals,

and/or indirect impacts related to cadmium

were summarized by Rand and Petrocelli [177].

A mouse hepatoma cell line selected for

resistance to cadmium (Cdr 80 hepa) was

compared to the unselected parental hepatoma

cell line (Cds hepa) in terms of its

sensitivity to a variety of metal ions. The

Cdr 80 hepa cells have double minute

chromosomes which carry amplified copies of

the MT-I and MT-II genes and can accumulate

approximately 20 fold more MT mRNA than Cds

hepa cells when stimulated with an optimal

sode of cadmium. The metals zinc, copper,

silver, cobalt, mercury, and bismuth also

induce higher levels of MT mRNA in the

resistant cells than in the unselected cells,

yet the Cdr 80 hepa cella only show increased

resistance to the toxic effects of zinc,

copper, mercury, and bismuth [366]. 

 

Potential Effects of Cadmium Upon Humans:

All cadmium compounds are potentially harmful or

toxic [83]. When cadmium is smelted, it vaporizes

into the atmosphere, and heavy concentrations can

cause kidney and bone-marrow diseases and emphysema

[335]. It has been implicated as the cause of

human deaths [379]. 
Cadmium is reported to block renal synth of 1,25-

dihydroxycholecalciferol, the metabolically active

form of vitamin D; this could be indirectly

responsible for skeletal abnormalities found in

cadmium embryotoxicity for lack of bone

mineralization & osteomalacia (Venugopal, B. and

T.D. Luckey. Metal Toxicity in Mammals, 2. New

York: Plenum Press, 1978. 82) [366].

Populations at special risk include [940]: 

1) Individuals with renal disease of other

etiology, which may add to or magnify the

effect of cadmium on the kidney. 

2) genetic differences in the induction of

metallothionein in response to cadmium

exposure; 

3) dietary deficiencies in metal ions and/or

protein, which may increase cadmium absorption

from the gastrointestinal tract; and, 

4) neonates or young children possibly having

higher gastrointestinal absorption rates than

adults. (DHHS/ATSDR; Toxicological Profile

for Cadmium, Draft p.62, 11/87). 

Human symptoms of exposure to cadmium include

[940]:

A. Inhalation (an asymptomatic period of 4-8

hr may precede the clinical illness). 1.

Metallic taste in the mouth and headache. 2.

Shortness of breath, chest pain, cough with

foamy or bloody sputum. Pulmonary rales and

related physical signs. 3. Weakness, leg

pains. 4. An asphyxial death from intense

pulmonary edema. 5. Gradual resolution of

pulmonary edema (over a period of a few days)

and development of fever, with persistence of

cough, chest pain and dyspnea for one or more

weeks. Physical signs of pneumonic

consolidation. 6. Late kidney and/or liver

damage has followed respiratory exposures in

industry. B. Ingestion (an asymptomatic period

of 1/2-1 hr may precede the clinical illness).

1. Severe nausea, vomiting, diarrhea and

abdominal cramps and salivation. 2. Headache,

muscular cramps, vertigo, and perhaps

convulsions (rarely). 3. Exhaustion, collapse,

shock and death, usually within a period of 24

hr. 4. The gradual evolution of signs and

symptoms of liver and kidney damage should be
anticipated but are rarely seen in man

(Gosselin, R.E., R.P. Smith, H.C. Hodge.

Clinical Toxicology of Commercial Products.

5th ed. Baltimore: Williams and Wilkins,

1984.,p. III-81) [940].

Inhalation of cadmium dusts, salts & fume over a

number of years result in chronic cadmium

poisoning, a disease characterized by distinctive,

nonhypertrophic emphysema with or without renal

tubular injury. Further inhalation overexposure

results in irreversible renal tubular damage, which

may progress into complete Fanconi syndrome with

decreased tubular reabsorption of proteins,

glucose, amino acids, calcium, phosphorus, & with

decreased ability to acidify & concentrate the

urine. Other toxic effects include anemia,

eosinophilia, anosmia, chronic rhinitis, yellow

discoloration of teeth, & bone changes (American

Conference of Governmental Industrial Hygienists.

Documentation of the Threshold Limit Values and

Biological Exposure Indices. 5th ed. Cincinnati,

OH:American Conference of Governmental Industrial

Hygienists, 1986. 87) [940].

Many nonfatal cases of "food poisoning" followed

ingestion of food kept for brief periods in cadmium

coated containers, such as ice cube trays & metal

pitchers. Welding (or cutting with acetylene

torch) cadmium-plated or cadmium containing metal

objects constitute very significant & potentially

lethal hazard after short exposures (same ... For

brazing or silver-soldering with cadmium-containing

rods or wires). Some silver solders contain more

than 20% cadmium. In early stages this syndrome may

be confused with a much more benign illness caused

by exposure to fumes of zinc & some other metals

(Gosselin, R.E., R.P. Smith, H.C. Hodge. Clinical

Toxicology of Commercial Products. 5th ed.

Baltimore: Williams and Wilkins, 1984.,p. III-77)

[940].

ATSDR has prepared a toxicological profile for

cadmium which summarizes human health effects via

various exposure routes [908]. Due to lack of

time, important highlights from this ATSDR document

have not yet been completely incorporated into this

entry. EPA has a (several page) health advisory on

this compound, available through the Office of

Drinking Water, EPA, Washington, D.C. or through

NTIS. 

Br.Car: Brief Summary of Carcinogenicity/Cancer Information:
Information from EPA 1996 IRIS [893]:

Weight-of-evidence classification: 

 Classification -- B1; probable human carcinogen by

inhalation; based on limited evidence from

epidemiologic studies and sufficient evidence of

carcinogenicity in rats and mice by two routes

[893].

Human carcinogenicity data: Limited. A 2-fold

excess risk of lung cancer was observed in cadmium

smelter workers. Studies of human ingestion of

cadmium are inadequate to assess carcinogenicity

[893]. 

Animal carcinogenicity data: Exposure of Wistar

rats by inhalation to cadmium as cadmium chloride

at concentrations of 12.5, 25 and 50 ug/cu.m for

18 months, with an additional 13-month observation

period, resulted in significant increases in lung

tumors. Intratracheal instillation of cadmium

oxide did not produce lung tumors in Fischer 344

rats but rather mammary tumors in males and tumors

at multiple sites in males. ...Seven studies in

rats and mice where cadmium salts (acetate,

sulfate, chloride) were administered orally have

shown no evidence of a carcinogenic response [893].

IARC Summary and Evaluation [940]:

Evaluation: There is sufficient evidence in humans

for the carcinogenicity of cadmium and cadmium

compounds. There is sufficient evidence in

experimental animals for the carcinogenicity of

cadmium compounds. There is limited evidence in

experimental animals for the carcinogenicity of

cadmium metal. In making the overall evaluation,

the Working Group took into consideration the

evidence that ionic cadmium causes genotoxic

effects in a variety of types of eukaryotic cells,

including human cells. Overall evaluation: Cadmium

and cadmium compounds are carcinogenic to humans

(Group 1). [IARC. Monographs on the Evaluation of

the Carcinogenic Risk of Chemicals to Man. Geneva:

World Health Organization, International Agency for

Research on Cancer,1972-PRESENT. (Multivolume

work).,p. 58 210 (1993)].

There is some evidence relating cadmium exposure to

prostate cancer in men and animal studies [1025]. 

Cadmium has been implicated in the increase in prostate

cancer incidence in men exposed to high levels. A

decrease in zinc and a concomitant increase in cadmium
levels in the human prostate has been shown. The role and

mechanism of cadmium action in prostate carcinogenesis is

not clear. Selenium, on the other hand, has been shown to

inhibit carcinogenesis in several animal systems. Results

show that cadmium stimulates the growth of human

prostatic epithelium in vitro between 10(-9) M and 10(-7)

M concentrations. Selenium, at concentrations between

10(-12) M and 10(-7) shows no growth stimulatory or

inhibitory effects on these cells. However, when present

at 10(-8) M level, selenium inhibits the growth

stimulation induced by cadmium (Webber MM; Biochem

Biophys Res Commun 127, 3: 871-7 (1985) [940].

Br.Dev: Brief Summary of Developmental, Reproductive,

Endocrine, and Genotoxicity Information:

Cadmium is listed as having some endocrine disruptive

activities [572]. Cadmium has been shown to cause birth

defects in mammals [61]. 

Mammals and birds consuming cadmium-contaminated food

have experienced lowered sperm counts, kidney damage,

increased mortality of young, elevated blood sugar, and

anemia [57]. From a variety of studies using mice and

bacteria as models, it appears likely that cadmium has

mutagenic effects [379]. 

Cadmium exposed, estradiol injected male and female

flounders showed depressed blood levels of vitellogenin

[982].

There are very few reports of cadmium-induced injury to

wildlife [838]. Incidents of cadmium poisoning in humans

and domestic animals have frequently been overlooked or

incorrectly diagnosed as something else due to the

multitude of interactions of cadmium with other essential

and toxic elements. The main clinical signs of cadmium

toxicity in animals are anemia, retarded gonad

development, enlarged joints, scaly skin, liver and

kidney damage, and reduced growth [838].

Evidence of gonadal effects from cadmium; microscopic

changes consisting of depression & maturation of

spermatocytes, associated with high levels of cadmium,

were found in testes of men exposed to cadmium fumes

(Clayton, G. D. and F. E. Clayton, eds.,. Patty's

Industrial Hygiene and Toxicology: Volume 2A, 2B, 2C:

Toxicology. 3rd ed. New York: John Wiley Sons, 1981-1982.

1569) [940].

Studies observed reproductive impairment to Ceriodaphnia

dubia at 6.0 ug/L cadmium [838]. One author has stated

that reproductive problems in fish may occur when tissue
concentrations exceed 0.1 mg/kg [57], but it is not clear

from the citation which kinds of tissues were meant. The

same paper discussed both whole body and edible tissue

data.

In rats, oral doses of cadmium given on days 6-19 of

gestation increased fetal resorption and caused skeletal,

kidney, and heart abnormalities in fetuses, stillborn,

and offspring. The incidence and intensity of skeletal

defects increased with cadmium dosage (Venugopal, B. and

T.D. Luckey. Metal Toxicity in Mammals, 2. New York:

Plenum Press, 1978. 83) [940]. For more details, see

Tis.Wildlife section below.

Br.Fate: Brief Summary of Key Bioconcentration, Fate,

Transport, Persistence, Pathway, and Chemical/Physical

Information:

Cadmium forms only bivalent compounds, which form

coordination compounds with other ions and molecules

[333]. Cadmium does not breakdown in the environment,

but it may be affected by physical and chemical processes

that modify its mobility, bioavailability, and residence

time in different environmental media [907]. The

environmental fate and transport of cadmium is greatly

dependent upon the local conditions and processes [838].

Cadmium tends to bioaccumulate in fish [57], clams

[90,95], and algae [95], especially in species living in

close proximity to sediments contaminated by cadmium

[95]. The mobility and bioavailability of cadmium in

aquatic environments is enhanced under conditions of low

pH, low hardness, low suspended matter levels, high redox

potential, and low salinity [907]. 

For many metals, alkalinity is sometimes a more important

co-factor for toxicity than hardness (Pat Davies,

Colorado Division of Wildlife, personal communication,

1997). Some recent research (1990) has focused on the

tendency of low-alkalinity (less than 50 ueq/L) waters to

have a relatively high potential for acid deposition

effects and increased bioaccumulation of cadmium in fish

[383]. See also the Bio.Detail section below. 

The movement of cadmium in soil and potential

accumulation in biota is enhanced by low pH, low organic

matter content, large soil particle size, and high soil

retention [907]. Soils generally function as a major

sink for most of the cadmium released into the

terrestrial environment [748]. In an experiment

conducted to follow the transfer of cadmium from a

terrestrial to an aquatic ecosystem, most (94 to 96%) of

the cadmium remained in the soil. Cadmium in the water
accumulated more rapidly in the sediments than in living

organisms. Twenty percent of the cadmium in water was

found in suspended particles [838]. 

A study of highway runoff indicated slight reductions of

cadmium in water after it had run through a sedimentation

pond and slightly more reduction after going from the

detention pond through a wetland [220].

 Biological Half-Life [366]:

An accumulation of cadmium occurs in many tissues and

particularly long half-times, 10-30 years, have been

reported for muscles, kidneys and liver. [Friberg, L.,

Nordberg, G.F., Kessler, E. and Vouk, V.B. (eds).

Handbook of the Toxicology of Metals. 2nd ed. Vols I,

II.: Amsterdam: Elsevier Science Publishers B.V.,

1986.,p. V2 130].

Synonyms/Substance Identification:

KADMIUM (GERMAN) [366]

C I 77180 [366] 

Colloidal cadmium [366]

 Molecular Formula [366]:

Cd 

Associated Chemicals or Topics (Includes Transformation Products):

Selenium seems to have some properties as an immunopotentiating agent, an agent which can bind mercury and

cadmium compounds to make them more biologically inert. See

Br.Car above for interactions between selenium and cadmium.

See also individual entry:

Mercury

Selenium

Water Data Interpretation, Concentrations and Toxicity (All Water

Data Subsections Start with "W."):

W.Low (Water Concentrations Considered Low):

No information found.

W.High (Water Concentrations Considered High):

A monitoring study of wastewater effluents from a waste

oil re-refinery in the United States (location not

specified) found that mean concentration of metals varied

from 0.34 mg/L for cadmium to 271 mg/L for lead [752].
Environmental accumulation: groundwater contamination

from electroplating operations has been reported to cause

concentrations of up to 3.2 mg/l cadmium (National

Research Council. Drinking Water & Health Volume 1.

Washington, DC: National Academy Press, 1977. 212) [940].

W.Typical (Water Concentrations Considered Typical):

Recent developments in new analytical methods, as well as

increased attention to sample preparation, have resulted

in reporting lower cadmium concentrations in surface

waters in the past decade (mid-1980s and 1990s) [838].

For example, a study reported that cadmium concentrations

in contaminated lakes in the Sudbury area ranged from 3

to 20 ug/l, but more recent measurements suggest levels

ranged as low as 0.08 ug/l [838]. In the same trend,

typical freshwater concentrations were reported by EPA in

1981 to be 0.08 mg/l (80 ug/L) [83]. However, it is now

understood that 80 ug/L is too high to be "typical"

[838].

Recent (1990s) measurements suggest that average total

cadmium concentrations in rivers, streams, and lakes are

in the range of less than 0.01 to 0.07 ug/l [838].

Reported background levels of cadmium in uncontaminated

compartments extend over several orders of magnitude (all

values in ug/L) [379]:

Freshwater 0.05 to 0.2

Coastal seawater up to 0.05

Open ocean seawater 0.01 to 0.1

Riverine and lake sediments up to 5000

Marine sediments 30 to 1000

Soils of nonvolcanic origin 10 to 1000

Typical Ocean Concentrations of Cadmium: EPA 1981:

0.00011 mg/l (0.11 ug/L) [83]. 

1971: A median concentration of 1 ug/L for U.S. surface

waters was reported (only 4% of samples exceeded 10 ug/L,

the older recommended limit for irrigation or drinking

water) [190].

USGS 1974-1981: The 50th percentile of 285 (not

especially clean) NASQWAN and NWQSS river sites in the

U.S. was <2 ug/l; as were the 25th and the 75th

percentiles, with concentrations trending upward more

often than downward, possibly partly due to atmospheric

deposition from fossil fuel combustion [219]. 

California, 1986: Ambient background level for water was

0.01 ug/l [222].
Great Lakes, 1990s: Total background cadmium

concentrations ranged from less than 0.02 to 0.10 ug/l.

Filtered total cadmium concentrations ranged from less

than 0.001 to 0.068 ug/l. The ratio of filtered to

unfiltered cadmium concentrations ranges from about 20 to

98% [838].

W.Concern Levels, Water Quality Criteria, LC50 Values, Water

Quality Standards, Screening Levels, Dose/Response Data, and

Other Water Benchmarks:

W.General (General Water Quality Standards, Criteria, and

Benchmarks Related to Protection of Aquatic Biota in

General; Includes Water Concentrations Versus Mixed or

General Aquatic Biota):

Notes on total vs. acid soluble vs. dissolved

metals:

Although most of the lab tests done to develop

water quality criteria and other benchmarks

were originally based on "total" values rather

than "dissolved" values, some regulatory

authorities nevertheless recommend comparing

criteria with dissolved or acid soluble metals

concentrations. For detailed discussion, see

the Laboratory and/or Field Analyses section

(far below).

EPA 1996 IRIS Database [893]:

Ambient Water Quality Criteria for Aquatic

Organisms

Acute Freshwater: 3.9E+0 ug/L 1-hour avg

[893].

Older References to same value:

Freshwater Acute Criteria: 3.9 ug/L

[689,649]. Hardness dependent

criterion rounded to second integer

(100 mg/L CaCO3 used) [689]. The

equation is Criteria = e to the

power of (1.128[ln(hardness)]-

3.828), where "e" = exponential

[649]. Further clarification:

e is the base of natural

logarithms and numerically

equals 2.72 (rounded), and

In(hardness) equals the natural

logarithm of the measured

hardness (Gary Rosenlieb,
National Park Service, Personal

Communication, 1997).

Chronic Freshwater: 1.1E+0 ug/L 4-day

avg [893]. 

Older References to same value:

Freshwater Chronic Criteria: 1.1

ug/L ([649,689]. Hardness dependent

criterion rounded to second integer

(100 mg/L CaCO3 used) [689]. The

equation is Criteria = e to the

power of (0.7852[ln(hardness)]-

3.490), where "e" = exponential

[649]. Further clarification:

e is the base of natural

logarithms and numerically

equals 2.72 (rounded), and

In(hardness) equals the natural

logarithm of the measured

hardness (Gary Rosenlieb,

National Park Service, Personal

Communication, 1997).

Marine Acute: 4.3E+1 ug/L 1-hour avg

[893]. 

Older Reference to same value [446].

Marine Chronic: 9.3E+0 ug/L 4-day avg

[893]. 

Older References to same value:

[446]. 

Reference: 50 FR 30784 (07/29/85) [893].

Contact: Criteria and Standards Division

/ OWRS / (202)260-1315 [893].

Discussion: Criteria were derived from a

minimum data base consisting of acute and

chronic tests on a variety of species.

The freshwater criteria are hardness

dependent. Values given here are

calculated at a hardness of 100 mg/L

CaCO3. A complete discussion can be

found in the referenced notice [893]. 

NOTE: Before citing a concentration as EPA's

water quality criteria, it is prudent to make

sure you have the latest one. Work on the

replacement for the Gold Book [302] was

underway in March of 1996, and IRIS is updated
monthly [893].

Oak Ridge National Lab, 1994: Ecological Risk

Assessment Freshwater Screening Benchmarks for

concentrations of contaminants in water [649]. To

be considered unlikely to represent an ecological

risk, field concentrations should be below all of

the following benchmarks (ug/L) [649]:

For CAS 7440-43-9, the cadmium benchmarks

are (ug/L) [649]:

NATIONAL AMBIENT WATER QUALITY

CRITERION - ACUTE: 3.9

NOTE: The above is a hardnessdependent criteria (100 mg/L

CaCO3 was used to calculate the

above concentration). For

sites with different water

hardness, site-specific

criteria should be calculated

with the following formula:

The Criteria is equal to:

e(1.128[ln(hardness)]-3.828),

where "e" = exponential [649].

Note: Same as IRIS 1996 EPA

equation given above [893].

Further clarification:

e is the base of natural

logarithms and

numerically equals 2.72

(rounded), and

In(hardness) equals the

natural logarithm of the

measured hardness (Gary

Rosenlieb, National Park

Service, Personal

Communication, 1997).

NATIONAL AMBIENT WATER QUALITY

CRITERION - CHRONIC: 1.1 

NOTE: The above is a hardness

dependent criteria (100 mg/L

CaCO3 was used to calculate the

above concentration). For

sites with different water

hardness, site-specific

criteria should be calculated

with the following formula:
The criteria is equal to: e to

the power of

(0.7852[ln(hardness)]-3.490),

where "e" = exponential [649].

Note: Same as IRIS 1996 EPA

equation given above [893].

Further clarification:

e is the base of natural

logarithms and

numerically equals 2.72

(rounded), and

In(hardness) equals the

natural logarithm of the

measured hardness (Gary

Rosenlieb, National Park

Service, Personal

Communication, 1997).

SECONDARY ACUTE VALUE: no

information found

SECONDARY CHRONIC VALUE: no

information found

LOWEST CHRONIC VALUE - FISH: 1.7

LOWEST CHRONIC VALUE - DAPHNIDS:

0.15

LOWEST CHRONIC VALUE - NON-DAPHNID

INVERTEBRATES: no information found

LOWEST CHRONIC VALUE - AQUATIC

PLANTS: 2

LOWEST TEST EC20 - FISH: 1.8

LOWEST TEST EC20 - DAPHNIDS: 0.75

SENSITIVE SPECIES TEST EC20: 0.013

POPULATION EC2O: 4.3

Other Concern Levels for Water Concentrations: 

Florida's water quality standard applied to

some wetland sites was 0.8 ug/l [220].

A State of California recommendation based on

direct toxicity was that 0.05 ug/L be the

water quality criteria (0.2 ug/l was an

adverse effects level) [222].
Canada's Interim Assessment Criterion for

cadmium in water is 1 ug/L [656].

NOTE: a) criterion is considered

"Interim" since complete supporting

rationale do not exist.

Canada's Remediation Criteria for cadmium for

freshwater aquatic life is 0.2-1.8 ug/L

(guideline changes with hardness) [656].

Other notes related to water standards [366]:

The ocean dumping, or transportation for

dumping, of materials containing cadmium or

cadmium compounds as other than trace

contaminants will not be approved on other

than an emergency basis [40 CFR 227.6(3)

(7/1/88)].

Toxic pollutant designated pursuant to section

307(a)(1) of the Clean Water Act and is

subject to effluent limitations [40 CFR 401.15

(7/1/88)].

W.Plants (Water Concentrations vs. Plants):

Shallow Groundwater Ecological Risk Assessment

Screening Benchmark for Terrestrial Plants Listed

by Oak Ridge National Lab, 1994 [651]:

To be considered unlikely to represent an

ecological risk, field concentrations in

shallow groundwater or porewater should be

below the following benchmark for any aqueous

solution in contact with terrestrial plants.

Toxicity of groundwater to plants may be

affected by many variables, such as pH, Eh,

cation exchange capacity, moisture content,

organic content of soil, clay content of soil,

differing sensitivities of various plants, and

various other factors. Thus, the following

solution benchmark is a rough screening

benchmark only, and site specific tests would

be necessary to develop a more rigorous

benchmark for various combinations of specific

soils and plant species [651]:

For CAS 7440-43-9, CADMIUM, the benchmark

is 0.05 mg/L (groundwater or porewater).

Canada's Remediation Criteria for cadmium for

irrigation water is 10 ug/L [656].
NOTE: This value is for total concentrations

in an unfiltered sample, and applies to all

soils. Guideline changes with hardness.

LC50 for various algae 0.06 to 0.16 mg/L [970].

W.Invertebrates (Water Concentrations vs. Invertebrates):

LC50 Daphnia magna 0.01 mg/L [970].

ACUTE: Reported 48-h acute toxicity values for

invertebrates range from 7.0 to 34,600 ug/L [838].

Cladocerans are particularly sensitive to cadmium.

The 48-hr LC50 for Daphnia magna is in the range of

34 to 60 ug/L in moderately hard water. The acute

toxicity of cadmium to D. magna was lower in water

with higher hardness. The lowest invertebrate

acute LC50 (7.0 ug/L) was reported for Simocephalus

serrulatus in wellwater [838].

CHRONIC: Adverse effects to aquatic invertebrates

are documented at relatively low cadmium

concentrations (0.28 to 3.0 ug/L), both in

laboratory and field studies. The 10-day LC50 for

the chironomid Tanytarsus dissimilis was 3.8 ug/L.

Studies observed reproductive impairment to

Ceriodaphnia dubia at 6.0 ug/L and suggest a

Maximum Allowable Toxicant Concentration (MATC) for

this species of 2.2 ug/L [838].

Some aquatic insects and crayfish demonstrate a

marked tolerance to cadmium relative to other

invertebrate species [838]. Cadmium concentrations

as high as 238 ug/L had little or no effect on the

survival of caddisfly (Hydropsyche betteni) and

stonefly (Pteronarcys dorsata). The 96-hr LC50 for

the mayfly Ephemerella grandis was 28,000 ug/L

[838].

W.Fish (Water Concentrations vs. Fish):

ACUTE: The 96-hr LC50 for rainbow trout parr in

soft (23 mg/L as CaCO3) water was 1.0 ug/L

[838,970]. The reported 96-hr LC50 for small (0.2

g) brook trout was 2.4 ug/L compared with 5080 ug/L

for 100-g brook trout. The toxicity of cadmium to

juvenile coho salmon was reduced in the presence of

organic complexing material [838]. 

The reported 96-h LC50 for fathead minnows ranged

from 11.7 to 7160 ug/L. Much of the variation is

related to the sensitivity of newly hatched fry

compared with older fish. For example, the 96-hr
LC50 for 1-day-old fry was in the range of 11.7 to

54.2 ug/L, compared with 1280 to 7160 for adult

(30+ -day-old) fathead minnows [838]. 

CHRONIC: Several studies reported chronic effects

of cadmium to fish at concentrations as low as 0.5

to 1.0 ug/L [838].

The subacute toxicity of cadmium to fish varies

greatly among species. Exposure to cadmium

concentrations from 0.5 to 5.2 ug/L for 168 to 408

hours caused 50% mortality in some stages of

rainbow trout, and coho and chinook salmon.

Survival and growth of sensitive life stages of

rainbow trout are often as sensitive and more

meaningful indicators of exposure to cadmium than

are biochemical or histological indices [838].

The toxic effects of cadmium are greatly influenced

by fish life stage. Embryos and newly hatched

alevins are more resistant to cadmium than are

older alevins or juveniles [838].

The lowest cadmium concentrations affecting growth

and survival of fathead minnows in exposures

ranging from 8 to 32 days were between 14.5 and

41.4 ug/L. Long-term exposure (126+ days) to

cadmium reduced growth and survival of brook trout

at 3.4 ug/L and 3.8 ug/L, respectively [838].

The 96-hr and 168-hr LC50s for 2- to 3-g steelhead

trout were less than 0.5 ug/L in water with a

hardness of 25 mg/L. Others report a 200-hr LC50

for steelhead fry of 1.3 ug/L in water of similar

hardness, but a higher calcium content (2.3 mg/L

calcium vs. 6.1 mg/L calcium).

W.Wildlife (Water Concentrations vs. Wildlife or Domestic

Animals):

To protect livestock/cattle use, cadmium levels

should be less than 0.01 mg/L [671]. 

Canada's Remediation Criteria for cadmium for

livestock watering is 20 ug/L (guideline is for

total concentrations in an unfiltered sample)

[656].

Oak Ridge National Lab, 1994: Risk Assessment

Screening Benchmarks for Wildlife derived from NoObserved-Adverse-Effect (NOAEL) levels (see

Tis.Wildlife, B) section below for these). To be

considered unlikely to represent an ecological
risk, water concentrations should be below the

following benchmarks for each species present at

the site [650]:

 CAS 7440-43-9 CADMIUM (AS SOLUBLE SALT) 

 WATER CONCEN-

 SPECIES TRATION (ppm)

Mouse (test species) 0.00000

Short-tailed Shrew 1.09300

Little Brown Bat 1.88900

White-footed Mouse 0.70600

Meadow Vole 1.23600

Cottontail Rabbit 0.58600

Mink 0.60700

Red Fox 0.43400

Whitetail Deer 0.24300

Comment: Actually, the number of

significant figures for a benchmark value

should never be more than one; even if

these values have been taken directly

from another report, they should be

rounded; otherwise the impression is

given of a level of accuracy that is

simply unwarranted. The uncertainties are

too large to justify such a fine

distinction (Owen Hoffman, SENES Oak

Ridge, Personal Communication, 1997).

W.Human (Drinking Water and Other Human Concern Levels):

EPA 1996 IRIS database information [893]:

Maximum Contaminant Level Goal

Value: 0.005 mg/L Status/Year: Final

1991 Econ/Tech?: No, does not consider

economic or technical feasibility

Reference: 56 FR 3526 (01/30/91) [893].

Contact: Health and Ecological Criteria

Division / (202)260-7571 Safe Drinking

Water Hotline / (800)426-4791 [893].

Discussion: Cadmium has been classed as

a Category III contaminant with an MCLG

of 0.005 mg/L based upon reports of renal

toxicity in humans. The MCLG is based

upon a DWEL of 0.018 mg/L and an assumed

drinking water contribution (plus aquatic

organisms) of 25 percent. An uncertainty

factor of 10 was also applied. [893].
Maximum Contaminant Level (MCL)

Value: 0.005 mg/L Status/Year: Final

1991 Econ/Tech?: Yes, does consider

economic or technical feasibility

Reference: 56 FR 3526 (01/30/91) [893].

Contact: Drinking Water Standards

Division / OGWDW / (202)260-7575 Safe

Drinking Water Hotline / (800)426-4791 

[893].

Discussion: EPA has promulgated an MCL

equal to the established MCLG of 0.005

mg/L. [893].

Ambient Water Quality Criteria for Human

Health [893]:

Water & Fish: 1E+1 ug/liter [893].

Older Values: Human Health Risk

Level for Carcinogens (risk of one

additional case in 1 million, 1E-06)

(ug/L): Published Criteria for Water

and Organisms: 10 [446]. Published

Criteria for Water and Organisms:

10 ug/L (this value is based on the

MCL; the toxicity-based value

calculated from CWA 304(a) = 29)

[689]. IRIS Recalculated (7/93)

Criteria for Water and Organisms: 14

[689].

Fish Only: None [893].

Older Values: Human Health Risk

Level for Carcinogens (risk of one

additional case in 1 million, 1E-06)

(ug/L): Published Criteria for

Organisms Only: None [446,689].

Previous IRIS Recalculated (9/90)

Criteria for Organisms Only: 170

ug/L [446]. Previous IRIS

Recalculated (7/93) Criteria for

Organisms Only: 84 ug/L [689]. 

Criteria Federal Register Notice

Number: 50 FR 30787, see also:

USEPA; Ambient Water Quality

Criteria Doc: Cadmium (1985) EPA

440/5-84-032.

Reference: 45 FR 79318 (11/28/80) 
[893].

Contact: Criteria and Standards Division

/ OWRS / (202)260-1315 [893].

Discussion: The criteria is the same as

the existing standard for drinking

water. [893].

Other EPA National Benchmarks [893]:

Drinking Water Crit. Dose: 0.005 mg/kg-day;

RfD: 5E-4 mg/kg-day Confidence: High [893].

EPA 1995 Region 9 PRG Tap Water Preliminary

Remediation Goal: 18 ug/L [868].

Other Drinking water benchmarks [859]:

The Maximum Acceptable Concentration (MAC) in

drinking water for Ontario's Ministry of the

Environment is 0.005 mg/L (5 ug/L).

The U.S. EPA lifetime health advisories for a

70-kg adult assuming, first, that 100% of a

person's exposure to the substance is from

drinking water, and second, that only 20% of a

person's exposure to the substance is from

drinking water, are 18.0 ug/L and 5.0 ug/L,

respectively.

The U.S. EPA 1-day, 10-day, and 7-year health

advisories for a 10-kg child consuming 1 L of

water per day are 43.0 ug/L, 43.0 ug/L, and

5.0 ug/L, respectively.

The U.S. EPA 7-year health advisories for a

70-kg adult consuming 2 L of water per day is

18.0 ug/L.

The European Economic Community's Maximum

Admissible Concentration (MADC) for cadmium is

5.0 ug/L.

The World Health Organization's Guideline

Value (GV) for cadmium is 0.005 mg/L.

Bureau of Land Management RMC Benchmarks, 1995:

Risk Management Criteria (RMC) were developed for

the mostly dry BLM lands in the western U.S. These

risk management criteria should be used by the land

manager as a cautionary signal that potential

health hazards are present and that natural

resource management or remedial actions are needed
[715]. Exceedances of the criteria should be

interpreted as follows [715]:

Less than criteria: low risk

1-10 times the criteria: moderate risk

10-100 times the criteria: high risk

>100 times the criteria: extremely high

risk

Human RMC criteria for cadmium in surface

waters: These categories of humans not

exposed to surface waters with concentrations

of cadmium exceeding the below RMCs are not

expected to experience adverse toxic effects

[715]:

Camp host: 155 ug/L

Child Camper: 142 ug/L

Boater: 553 ug/L

Swimmer: 239 ug/L

Human RMC criteria for cadmium in ground

water: These categories of humans not exposed

to ground waters with concentrations of

cadmium exceeding the below RMCs are not

expected to experience adverse toxic effects

[715]:

Child resident (living on properties

adjacent to BLM lands): 0.2 ug/L

Camp host: 2 ug/L

Child Camper: 5 ug/L

Worker: 4 ug/L

Surveyor: 39 ug/L

W.Misc. (Other Non-concentration Water Information):

Elevated cadmium concentrations have been reported in

lower trophic levels in acidified lakes [838]. This had

led to speculation that piscivorous or predatory animals

could be exposed to higher cadmium concentrations in

acidified watersheds. Studies in the U.S., Canada, and

Sweden report that lake cadmium concentrations were

inversely correlated with lake pH. An inverse

relationship between cadmium concentrations and lake pH

has been observed for yellow perch, bluegill sunfish,

suckers, and various invertebrate species [838].

Cadmium can enter surface waters from the natural sources

and from a variety of manufacturing operations that

involve either cadmium itself or zinc that contains a

cadmium impurity. Cadmium can enter the water environment

from the plating operations when spent plating solutions
are discarded. The production of refined cadmium metal is

a potential source of cadmium in nearby surface waters

from ore tailings and washings (IARC. Monographs on the

Evaluation of the Carcinogenic Risk of Chemicals to Man.

Geneva: World Health Organization, International Agency

for Research on Cancer,1972-PRESENT, Multivolume

work,.,p. V2 80, 1973) [940].

Total vs. dissolved water concentrations:

A potential complication in comparing contaminants

data is that different investigators have sometimes

meant different things when they put the words

"dissolved" or "total" in front of a reported

measurement. In the case of nutrients, the

"dissolved" portion is usually simply that portion

which has passed through a 0.45-micrometer membrane

filter and the "total" measurements implies that it

was not filtered and includes both dissolved and

other forms of the nutrient [141]. However, usage

of the words dissolved and total has not been

uniform in the past and there is still considerable

debate about which methods should truly be

considered "dissolved" or "total" (Merle Schlockey,

USGS, personal communication).

Water bodies are often marked by heterogeneity of

the distribution of undissolved materials [691].

The size of any effects depends on the difference

in density of the undissolved materials and the

water, the size of the particles or bubbles of the

materials, and various hydrodynamic factors such as

the degree of turbulence in the water. Thus,

undissolved inorganic materials in rivers and other

natural water-bodies tend to increase in

concentration with increasing depth because the

particles tend to settle [691]. On the other hand,

certain biological detritus may tend to rise

towards the surface of the water because its

density is less than that of water; oils also

commonly demonstrate this effect markedly [691].

The surface microlayer is usually higher in

concentration of many metallic and organic

contaminants than the water column further down. 

If the only change one makes is to use the prefix

"dissolved" rather than the prefix "total" in an

otherwise identical water quality standard, the

effect can be a weakening of the standard related

to total loading of a system. Many contaminants

which are not currently dissolved can become

dissolved at a later time, when encountering

different conditions (perhaps downstream), such as

changes in pH, additions of surfactants or humic
substances, bioturbation, methylating organisms,

and various other physical, chemical, or biological

changes.

One problem with relying too heavily on dissolved

fractions of metals is that the dissolved fraction

misses the metals carried by colloids. Colloids

were found to carry toxic metals 140 miles

downstream of mining sources in Leadville,

Colorado, to be repeatedly washed from flood

deposited lowlands back into the river year after

year in spring runoff (Briant Kimball, USGS Salt

Lake City, as quoted in U.S. Water News, April 5th,

1995).

See Laboratory section below for EPA generic

(guesstimate) conversion factors to convert total

to dissolved concentrations.

Some environmental toxicologists make the argument

that dissolved metals in surface water and

porewaters represent most of what is bioavailable

and thus "total" metals parameters are not good as

a measure of potential biological effects. This is

mostly true in many situations, but it should be

kept in mind that fish and other aquatic organisms

do not typically live in filtered water and that

many fish and other aquatic organisms live in the

sediments and in other situations in which they

come in contact with toxic or otherwise harmful

compounds (as certain colloids, precipitates,

oxides, adsorbed metals), etc. Sometimes the

effect of total metals is partially related to

physical or chemical aspects, such as when ferric

oxide coats or covers benthic organisms. Another

factor to consider: contaminants carried downstream

by erosion of bottom sediments or colloids can be

mobilized when they come in contact with different

physical/chemical environments downstream (for

example, a tributary bringing low pH into the

system).

Misc. Notes on colloids (Briant Kimball, USGS,

Salt Lake City Office, Personal Communication,

1995):

There is no question that dissolved

metals are critical to fish and

invertebrates, but less well recognized

is the potential impact and movement of

metals in colloids. The possibility of

having colloidal material present means

there is a readily available supply of

metals in a state in which the metals can
quickly be reduced and mobilized. In

river banks, reducing environments form

just under the surface quickly. Toxic

metals of concern would include zinc,

lead, copper, and cadmium.

Colloids do move in surface water (for

example, transport of metal in colloids

140 miles downstream of Leadville, CO),

but also in groundwater, especially

related to radionuclides. 

Colloidal metals may effect biota more

than is widely recognized. Brown trout

are effected by colloids which travel

kind of like dissolved fractions, don't

settle out. There may be little

understood colloidal pathways of metals

to fish, for example. Colloidal metals

become part of the caddis cast which are

ingested, once part of acid gut, metals

can be released. On the Arkansas River

of Colorado below Leadville, the

dissolved metals have gone down with

treatment, but Will Clements of CSU has

discovered the toxicity has not been

reduced to the same extent as have the

dissolved metals. Treatment has not

eliminated colloidal fractions loaded

with cadmium and copper, and this is

possibly impacting the fish. 

In rivers, there is annual flushing of

the colloids, loads are much greater

during runoff.

Sediment Data Interpretation, Concentrations and Toxicity (All

Sediment Data Subsections Start with "Sed."):

Sed.Low (Sediment Concentrations Considered Low):

No information found.

Sed.High (Sediment Concentrations Considered High):

Texas: The statewide 90th percentile value for this

compound was 3.0 mg/kg dry weight [7].

Great Lakes Harbors, EPA 1977: Sediments having sediment

concentrations higher than 6.0 mg/kg dry weight were

classified as "heavily polluted [145]." 

Illinois EPA, 1984: Sediments having sediment
concentrations higher than 1.0 mg/kg dry weight were

classified as "elevated" [145]. 

NOAA National Status and Trends Program (1984-1990)

[698]: High concentration for cadmium in fine-grained

sediment (n=233) = 1.2 ug/g dry weight at 4.6% TOC dry

weight. The above concentration was adjusted for

sediment grain-size in the following way: the raw

concentrations were divided by the fraction of particles

less than or equal to 64 um. "High" NOAA concentrations

are equal to the geometric mean plus one standard

deviation on the log normal distribution [696].

NOTE: Fine-grained sediment would typically

contain more cadmium than course-grained sediment,

and sediments higher in total organic carbon (TOC)

would typically have more cadmium than sediments

which are similar except for being lower in TOC,

which is why NOAA and many others are now

normalizing sediment values for grain size, and

reporting TOC.

Cadmium was detected in 89% of urban-bay samples from the

Puget Sound area. The mean concentration was 1.8 mg/kg

dry weight (ppb), while the median concentration was 0.6

mg/kg (ppm) [852].

NOTE: The above values are not normalized for

total organic carbon (TOC) content.

Gradient Monitoring Levels: Cadmium showed a general

tendency to increase from upstream to downstream in

Trinity River sediments [201]. The same trend was shown

in sediment samples in a 1977 study by the Texas Water

Quality Board. Elevated concentrations of cadmium have

been found in sediments from downstream of Dallas

[42,74]. Sediments from Beltline Road (6.5 miles

downstream of our site 11) were 12.0 mg/kg, the highest

recorded in the State at that time [74]. The highest

levels of cadmium (7.0 to 12.0 mg/kg) were found in

sediment samples from sites 9 through 12 (using our site

numbers), with much lower concentrations upstream [74].

Sediment concentrations of cadmium from polluted Trinity

River sites exceeded the statewide 90th percentile level,

3.0 mg/kg, in at least 50% of the historical records from

1974 to 1985 [7]. Cadmium has also been reported to have

been highly elevated in sediments as far south as highway

31 near Trinidad [91]. A cycle of biomobilization of

sedimentary cadmium by algae, followed by movement of the

algae downstream and return of the cadmium to the

sediments when the algae dies, may play a role in moving

cadmium downstream [95].

Analyses of sewage sludges from 50 publicly owned
treatment works by the U.S. Environmental Protection

Agency (1985): The mean concentration of cadmium was

32.2 ppm (dry weight) [347].

Analyses of 74 Missouri sewage sludges (1985). The

median for Cadmium was 8.1 ppm of the dry weight. The

range for cadmium was 1.7-320 ppm of the dry weight

[347].

Sed.Typical (Sediment Concentrations Considered Typical):

The International Joint Commission considered <0.6 mg/kg

as a background sediment level [145]. The control site

in one Great Lakes study had a sediment concentration of

0.32 mg/kg dry weight [145].

NOAA National Status and Trends Program (1984-1990)

[698]: Geometric mean for cadmium in fine-grained

sediment (n=233) = 0.48 ug/g dry weight at 1.4% TOC dry

weight. The above concentration was adjusted for

sediment grain-size in the following way: the raw

concentrations were divided by the fraction of particles

less than or equal to 64 um. 

NOTE: Fine-grained sediment would typically contain

more cadmium than course-grained sediment, and

sediments higher in total organic carbon (TOC)

would typically have more cadmium than sediments

which are similar except for being lower in TOC,

which is why NOAA and many others are now

normalizing sediment values for grain size, and

reporting TOC.

Cadmium was detected in 96.8% of non-urban-bay samples

from the Puget Sound area. The mean concentration was

0.9 mg/kg dry weight (ppb), while the median

concentration was 0.28 mg/kg (ppm) [852]. 

NOTE: The above values are not normalized for

total organic carbon (TOC) content.

Sed.Concern Levels, Sediment Quality Criteria, LC50 Values,

Sediment Quality Standards, Screening Levels, Dose/Response

Data and Other Sediment Benchmarks:

Sed.General (General Sediment Quality Standards,

Criteria, and Benchmarks Related to Protection of Aquatic

Biota in General; Includes Sediment Concentrations Versus

Mixed or General Aquatic Biota):

Oak Ridge National Lab, 1994: Risk Assessment

Screening Benchmarks for Sediment Concentrations.

To be considered unlikely to represent an
ecological risk, field concentrations should be

below all of the following benchmarks in mg/kg

(ppm) dry weight [652]:

 CAS 7440-43-9, CADMIUM

LOWEST EFFECT LEVEL (ONTARIO MOE): 0.6

EFFECTS RANGE - LOW (NOAA): 1.2

EFFECTS RANGE - MEDIAN (NOAA): 9.6

Other Concern Levels for Cadmium Sediment

Concentrations (Dry Weight):

Guidelines for the pollution classification of

Great Lakes harbor sediments (1977):

Guidelines have not been established for

nonpolluted or moderately polluted but the

guideline for heavily polluted water is

greater than 75 ppm (dry weight) [347].

Wisconsin interim criteria for sediments from

Great Lakes harbors for disposal in water

(1985): Cadmium should not exceed 1.0 ppm

(dry weight) [347].

EPA Region 6, 1973: The cadmium concentration

proposed by EPA Region 6 as a guideline for

determining acceptability of dredged sediment

disposal was 2.0 mg/kg [143].

Ontario, 1978, 1986: The cadmium

concentration proposed by the Ontario Ministry

of the Environment as a threshold for

evaluations of dredging projects was 1.0 mg/kg

[145]. Ontario Ministry of the Environment

guidelines for open lake disposal of sediments

(1986): the guideline for cadmium is 1 ppm

[347].

International Joint Commission, 1988: The IJC

suggested sediment concentrations of cadmium

not exceed background levels of 0.6 mg/kg

[145].

AET 1988: The apparent effects threshold

concentrations for cadmium in sediments

proposed for Puget Sound ranged from 5.1 mg/kg

dry weight (benthic species) to 9.6 mg/kg dry

weight (microtox) [416]. 

NOTE: Although the authors of the Puget

Sound AETs have cautioned that Puget

Sound AETs may not be appropriate for

comparison with data from other
geographic areas, so few concern levels

for this chemical have been published

that the proposed Puget Sound concern

level is included in this text as an item

of interest.

NOAA 1995 Concern Levels for Coastal and

Estuarine Environments: After studying its

own data from the National Status and Trends

Program as well as many literature references

concerning different approaches to determining

sediment criteria, NOAA suggested that the

potential for biological effects of this

contaminant sorbed to sediments was highest in

sediments where its concentration exceeded

the 9.6 ppm dry weight Effects Range-Median

(ERM) concentration and was lowest in

sediments where its concentration was less

than the 1.2 ppm dry weight Effects Range-Low

(ERL) concentration [664]. To improve the

original 1990 guidelines [233], the 1995

report included percent (ratios) incidence of

effects for ranges below, above, and between

the ERL and ERM values. These numbers

represent the number of data entries within

each concentration range in which biological

effects were observed divided by the total

number of entries within each range [664]:

<ERL 6.6

ERL-ERM 36.6

>ERM 65.7 

Ontario Ministry of the Environment Freshwater

Sediment Guidelines, 1993: Lowest effect level:

0.6 mg/kg dry weight. Severe effect level: 10

mg/kg dry weight [761].

St. Lawrence Interim Freshwater Sediment Criteria,

1992: No effect: 0.2 mg/kg dry weight. Minimal

effect: 0.9 mg/kg dry weight. Toxic effect: 3

mg/kg dry weight [761].

Environment Canada Interim Sediment Quality

Assessment Values, 1994: Threshold Effect Level:

0.596 mg/kg dry weight. Probable Effect Level:

3.53 mg/kg dry weight [761].

Sed.Plants (Sediment Concentrations vs. Plants):

No information found.

Sed.Invertebrates (Sediment Concentrations vs.
Invertebrates):

No information found.

Sed.Fish (Sediment Concentrations vs. Fish):

No information found.

Sed.Wildlife (Sediment Concentrations vs. Wildlife or

Domestic Animals):

Bureau of Land Management RMC Benchmarks, 1995:

Risk Management Criteria (RMC) were developed for

the mostly dry BLM lands in the western U.S. These

risk management criteria should be used by the land

manager as a cautionary signal that potential

health hazards are present and that natural

resource management or remedial actions are needed

[715]. Exceedances of the criteria should be

interpreted as follows [715]:

Less than criteria: low risk

1-10 times the criteria: moderate risk

10-100 times the criteria: high risk

>100 times the criteria: extremely high

risk

Wildlife criteria for cadmium in soils and

sediments: Wildlife not exposed to

soils/sediments with concentrations of cadmium

exceeding the below RMCs are not expected to

experience adverse toxic effects [715]:

 Deer/Mouse: 1 mg/kg

Rabbit: 3 mg/kg

 Bighorn Sheep: 6 mg/kg

 Whitetailed Deer: 2 mg/kg

 Mule Deer: 2 mg/kg

 Elk: 2 mg/kg

 Mallard: 3 mg/kg

 Canada Goose: 3 mg/kg

 Trumpeter Swan: 3 mg/kg

Sed.Human (Sediment Concentrations vs. Human):

Bureau of Land Management RMC Benchmarks, 1995:

Risk Management Criteria (RMC) were developed for

the mostly dry BLM lands in the western U.S. These

risk management criteria should be used by the land

manager as a cautionary signal that potential

health hazards are present and that natural

resource management or remedial actions are needed

[715]. Exceedances of the criteria should be
interpreted as follows [715]:

Less than criteria: low risk

1-10 times the criteria: moderate risk

10-100 times the criteria: high risk

>100 times the criteria: extremely high

risk

Human RMC criteria for cadmium in sediments:

These categories of humans not exposed to

sediments with concentrations of cadmium

exceeding the below RMCs are not expected to

experience adverse toxic effects [715]:

 Camp host: 155 mg/kg

 Child Camper: 71 mg/kg

 Boater: 553 mg/kg

 Swimmer: 239 mg/kg

Sed.Misc. (Other Non-concentration Sediment Information):

Acid volatile sulfides (AVS) have been proposed as a

sediment normalization measure to help in data

interpretation related to the sediment toxicity of metals

and mixtures of metals. It has been proposed that the

extent to which metals bind to sediments is related to

the acid volatile sulfide concentrations. It has been

shown that acid volatile sulfides is the sediment phase

that determines the extent of cadmium toxicity in fresh

water sediments (see abstract listed below). Our ability

is to use acid volatile sulfide normalization of sediment

toxicity is better for marine waters than for

freshwaters. 

In freshwater, use of AVS for data interpretation is

still in the developmental stage, and usually requires

that total organic carbon (TOC) also be measured; acid

volatile sulfide normalization is thus far more useful

for predicting no toxicity than in predicting exactly

what the toxicity will be (Bill Brumbaugh, Columbia

National Fisheries Contaminant Research Center, Fish and

Wildlife Service, personal communication). 

In early 1995, proposals were circulating in EPA

suggesting that lower bound metals sediment criteria be

developed along the following line: if sufficient AVS is

present [that is, the total simultaneously extracted

metal (SEM) is equal or less than the concentration of

AVS, then no effects are expected [700]. If SEM exceeds

AVS, then other binding phases become important; the next

most important phase is organic carbon (TOC) [700]. EPA

now suggests that AVS be conducted in combination with

interstitial water, particularly if effects are seen when
AVS criteria are not exceeded [700].

Some have argued that AVS is not necessary for biological

assessment work because significant AVS presence reflects

anoxic conditions and AVS tends to go to zero when

exposed to oxygen. Great care must be taken when

collecting sediment samples for AVS not to expose them to

air. Since most living things require oxygen, if there

is no oxygen there are few if no living things so why use

AVS to look at toxicity aspects (Tom O'Connor, NOAA,

personal communication, 1995)?

Others would respond that it seems to work as a toxicity

normalization parameter anyway, and point out that

certain invertebrates, bacteria, etc. do live in low

oxygen conditions in sediments. For mid to high range

levels of AVS, exposure to air while sampling does not

seem to critical, though head space in the jar should be

minimized. As of October, 1995, the EPA method for AVS

(method 376.3, similar but different from older reactive

sulfide methods) was still a draft. AVS detection limits

should be down in the 3 ppm range (~0.1 micro mole); any

lower than that and the problems of lack of buffering and

field contamination of samples by air or redox changes

become more critical (Bill Brumbaugh, Columbia Lab, NBS,

personal communication, 1995).

Information on acid volatile sulfides, summarized from

Suter 1993 [577]:

DiToro et al. have proposed a model that used acid

volatile sulfide (AVS) concentrations to normalize

sediment concentrations of metals to pore water

concentrations. It is believed to be applicable to

metals whose sulfides are less soluble than FeS.

Where only one metal competes for the AVS, the

molar equivalent of the AVS would not be

bioavailable, so the concentration in sediment

(C(st), umol/g) that is equitoxic to a

concentration in water (C(wt), umol/L) is: C(st) =

AVS + K(p) C(wt) [577]. This model is not

applicable to fully oxidized sediments and to

sediments with extremely low AVS (< 1 umol/g).

This model is fairly difficult to use because there

is no ready means to estimate K(p), because of the

need to account for competition among metals for

AVS, because AVS is not routinely measured like

f(oc), and because AVS can be seasonably variable

[577].

Relevant Abstract: Di Toro DM; Mahony JD; Hansen DJ;

Scott KJ; Hicks MB; Mayr SM; Redmond MS AF, Environ. Eng.

and Sci. Program, Manhattan Coll., Bronx, NY 10471, USA

Toxicity of cadmium in sediments: The role of acid
volatile sulfide. ENVIRON. TOXICOL. CHEM.; vol. 9, no.

12, pp. 1487-1502; 1990: 

The toxicity of chemicals in sediments is

influenced by the extent that chemicals bind to the

sediment. It is shown that acid volatile sulfide

(AVS) is the sediment phase that determines the

LC50 for cadmium in the marine sediments tested.

Although it is well known that metals can form

insoluble sulfides, it apparently has not been

recognized that AVS is a reactive pool of solid

phase sulfide that is available to bind with

metals. Amphipod sediment toxicity tests were

conducted in the laboratory and the observed

amphipod LC50s on a normalized cadmium

concentration basis, (Cd)/(AVS), is the same for

sediments with over an order of magnitude

difference in dry weight normalized cadmium LC50s.

Soil Data Interpretation, Concentrations and Toxicity (All Soil

Data Subsections Start with "Soil."):

Soil.Low (Soil Concentrations Considered Low):

The lowest average cadmium content is found in highly

leached spodosols (0.37 ppm) [699].

Soil.High (Soil Concentrations Considered High):

The highest average cadmium content is found in organic

soils (0.78 ppm) [699].

Cadmium in German Gulch (Upper Clark Fork Superfund Site

Area, Montana) samples ranged from 1.3 to 5.1 ppm and

averaged 3.0 ppm [699].

A detailed investigation of cadmium levels in a Montana

valley contaminated with cadmium from a zinc smelter

reported that upper-soil cadmium levels decreased from

27.3 ug/g at 1.5 miles distant from the smelter to 1.5

ug/g at 21.0 miles away [838].

Analyses of sewage sludges from 50 publicly owned

treatment works by the U.S. Environmental Protection

Agency (1985): The mean concentration of cadmium was

32.2 ppm (dry weight) [347].

Analyses of 74 Missouri sewage sludges (1985). The

median for Cadmium was 8.1 ppm of the dry weight. The

range for cadmium was 1.7-320 ppm of the dry weight

[347].

Soil.Typical (Soil Concentrations Considered Typical):
Level of cadmium in surface soils worldwide [855]: 0.1

-1.0 ug/g; mean 0.62 ug/g

Reported background levels of cadmium in uncontaminated

soils of non-volcanic origin [379]: 0.010 to 1.0 ppm

EPA 1981: 0.06 mg/kg dry weight not considered elevated

[83]. Igneous Rocks (Earth's Crust) Concentrations not

Considered Elevated: EPA 1981: 0.2 mg/kg dry weight

[83]. Another reference stated the national average

concentration for cadmium in U.S. soils is 5 mg/kg [98].

Average soil concentrations of cadmium in the United

States range between 0.005 and 2.4 ppm (Alloway, 1990)

[699].

The calculated worldwide mean of cadmium in surface soils

is 0.53 ppm (range 0.005-2.4 ppm) [699].

Western U.S. Soil Median Concentrations [715]: 0.32 mg/kg

Soil.Concern Levels, Soil Quality Criteria, LC50 Values, Soil

Quality Standards, Screening Levels, Dose/Response Data and

Other Soil Benchmarks:

Soil.General (General Soil Quality Standards, Criteria,

and Benchmarks Related to Protection of Soil-dwelling

Biota in General; Includes Soil Concentrations Versus

Mixed or General Soil-dwelling Biota):

Proposals for Maximum Acceptable Concentrations

(MAC) of Cadmium in Agricultural Soils as Given by

Various Authors (ppm dry weight) [719]:

Other MAC levels: 3 ppm dry weight (Stuttgart,

Germany), 3.5 ppm dry weight (London).

Proposal of European Economic Commission for

MAC in soils treated with sewage sludge: 1 (3)

ppm dry weight (London).

NOTE: The value in parentheses is a

mandatory concentration. 

Proposal of Ontario Ministry of Agriculture

and Food for MAC in soils treated with sewage

sludge: 1.6 ppm dry weight (published in

Tokyo; work done for Ontario).

Cadmium: A facility or practice concerning

application of solid waste to within one meter

(three feet) of the surface of land used for the

production of food-chain crops shall not exist or
occur, unless in compliance with requirements given

in 40 CFR 257.3-5, which limit cadmium content in

the solid waste. /Cadmium containing solid waste/

(40 CFR 257.3-5, 7/1/88) [366,940].

Soil criteria for evaluating the severity of

contamination under the Dutch Soil Cleanup

(Interim) Act (1982): background concentrations is

soil or detection limits 1 ppm, moderate soil

contamination 5 ppm, threshold values that require

immediate cleanup 20 ppm [347].

Soil cleanup criteria for decommissioning

industrial sites in Ontario (1987): Cadmium should

not exceed 1-6 ppm for agricultural land, 4 ppm for

residential/parkland, 8 ppm for

commercial/industrial land [347].

Suggested cleanup guidelines for inorganic

contaminants in acidic soils in Alberta (1987).

Acceptable level of cadmium for acidic soils

(pH<6.5) is 1.0 ppm [347].

Quebec soil contamination indicators that differ

from those of the Netherlands (1987): Background

concentrations in soil or detections limit of

cadmium is 1.5 ppm, moderate soil contamination is

5 ppm, threshold value that requires immediate

cleanup is 20 ppm [347].

Maximum cumulative addition of metals (kg/ha) from

sewage sludge to Maryland agricultural soil (1986):

For a soil with a cation exchange capacity (CEC) of

<5 meq/100g cadmium should not be added at greater

than 5 kg/ha. For a soil with a CEC of greater

than 5 meq/100g cadmium addition should not exceed

10 kg/ha [347].

Maximum cumulative addition of metals (kg/ha) from

sewage sludge to Massachusetts agricultural soil

(1983): For a soil with a cation exchange capacity

(CEC) of less than 5 meq/100g addition of cadmium

should not exceed 5 kg/ha. For a soil with a

cation exchange capacity of greater than 5 meq/100g

cadmium addition should not exceed 5 kg/ha [347].

Maximum cumulative addition of metals from sewage

sludge that may be added to Minnesota soils used

for growing food crops (1987): For a soil with a

cation exchange capacity (CEC) of less than 5

meq/100g cadmium should not be added at greater

than 5 kg/ha, for a soil with a CEC between 5 and

15 cadmium should not be added at greater than 10

kg/ha, for a soil with a CEC of greater than 15
meq/100g cadmium should not be added at greater

than 20 kg/ha [347]. These values are also the

same for the maximum cumulative addition of metals

(kg/ha) from sewage sludge recommended for

privately owned Missouri (1988) and Oregon (1984)

farmland [347].

Cumulative amounts of metals per hectare that may

be added to New York State soils with sewage sludge

(1988): For more productive agricultural soils it

is 3.4 kg/ha and for less productive agricultural

soils it is 4.5 kg/ha. For dedicated lands

(forests) is 11 [347].

The maximum cumulative additions (kg/ha) of metals

from sewage sludge that may be added to Vermont

soils by soil texture (1984): For loamy sand it is

6 kg/ha, fine sandy loam is 11 kg/ha, and clay

loam, clay or silty clay is 22 kg/ha [347].

The maximum cumulative addition (kg/ha) of cadmium

from sewage sludge that my be added to Wisconsin

soils (1985): With a pH less than 6.5 if the soil

cation exchange capacity is less than 5 meq/100g

cadmium should not be added at greater than 5

kg/ha. If the CEC is between 5 and 15 meq/100g

cadmium should not be added at greater than 5

kg/ha. If the CEC is greater than 15 meq/100 g

cadmium should not be added at greater than 5

kg/ha. For soils with a pH greater than 6.5 and a

CEC less than 5 meq/100 g cadmium should not be

added at greater than 5 kg/ha. For a soil with a

CEC between 5 and 15 meq/100g cadmium should not be

added at greater than 10 kg/ha. For a soil with a

CEC of greater than 15 meq/100g cadmium should not

be added at greater than 20 kg/ha [347].

Soil limit values for cadmium determined by the

Council of European Communities for the addition of

heavy metals from sewage sludge to soil with a pH

of 6.0-7.0 (1986): 1-3 ppm [347].

The 1987 soil (clean up) criteria given by the New

Jersey Department of Environmental Protection for

cadmium: 3 mg/kg dry weight [347,386].

In 1981 the U.S. Environmental Protection Agency

proposed 25 ppm as an upper limit for cadmium for

sewage sludges suitable for land application [391].

Soil.Plants (Soil Concentrations vs. Plants):

Levels of cadmium (ppm dry weight) considered
phytotoxic: 5 (Vienna), 3-5 (Warsaw), 3 (Warsaw),

8 (Ontario) [719].

Minimum soil concentration causing phytotoxicity:

3-5 ppm [699].

Oak Ridge National Lab, 1994, Risk Assessment

Screening Benchmarks for Terrestrial Plants: To be

considered unlikely to represent an ecological risk

to terrestrial plants, field concentrations in soil

should be below the following dry weight benchmark

for soil in mg/kg (ppm) [651]:

 For CAS 7440-43-9, (Cadmium) the Soil

Benchmark is 3 mg/kg.

In general, it has been found that for many soils,

the concentration of cadmium in plants shows a

positive correlation with the level of cadmium

present in or added to the soil [748]. The

relationship holds even at very low rates of

cadmium addition to the soils. In terms of cadmium

uptake, it thus appears that there is no known

threshold for safe concentration of cadmium in the

soil [748].

Soil pH is particularly important in determining

the amount of cadmium taken up from the soils

[748]. A reduction in pH often enhances the

cadmium uptake by plants. Other physicochemical

properties of soils that affect the uptake of

cadmium by crops include 1) the oxidation-reduction

potential of soils, 2) soil temperature, 3) clay

content and cation exchange capacity, 4)

concentrations of iron, manganese, and aluminum

oxides and hydroxides, 5) presence of anions that

can immobilize the cadmium, 6) organic matter

concentration, and 7) interactive effects of zinc,

copper, nickel manganese, and selenium [748].

In a village in Japan where the agricultural soil

was contaminated by tailings from an old zinc

mining operation the vegetables grown there showed

cadmium concentrations that were about 15 times

above the normal values [748].

Soil.Invertebrates (Soil Concentrations vs.

Invertebrates):

A detailed investigation of cadmium levels in a

Montana valley contaminated with cadmium from a

zinc smelter reported that upper-soil cadmium

levels decreased from 27.3 ug/g at 1.5 miles
distant from the smelter to 1.5 ug/g at 21.0 miles

away. About 99% of the cadmium present in the

ecosystem was contained in the soil compartment,

with decreasing amounts at higher trophic levels.

The levels of cadmium in grasshoppers (1.0-2.3

ug/g) were two to three times the levels present in

vegetation [838].

 

Soil.Wildlife (Soil Concentrations vs. Wildlife or

Domestic Animals):

See Sed.Wildlife section above.

Soil.Human (Soil Concentrations vs. Human):

EPA 1996 National Generic Soil Screening Level

(SSL) designed to be conservative and protective at

the majority of sites in the U.S. but not

necessarily protective of all known human exposure

pathways, land uses, or ecological threats [952]:

SSL = 78 mg/kg for ingestion pathway [952].

SSL = 1800 mg/kg for inhalation pathway [952].

SSL = 0.4 to 8 mg/kg for protection from

migration to groundwater at 1 to 20 DilutionAttenuation Factor (DAF) [952].

 EPA 1995 Region 9 Preliminary remediation goals

(PRGs), 1995 [868]:

Residential Soil: 38 mg/kg wet wt.

Industrial Soil: 850 mg/kg wet wt.

NOTE:

1) PRGs focus on the human exposure pathways

of ingestion, inhalation of particulates and

volatiles, and dermal absorption. Values do

not consider impact to groundwater or

ecological receptors.

2) Values are based on a non-carcinogenic

hazard quotient of one.

3) PRGs for residential and industrial

landuses are slightly lower concentrations

than EPA Region III RBCs, which consider fewer

aspects [903].

 EPA 1995 Region 3 Risk based concentration (RBC) to

protect from transfers to groundwater: 

6 mg/Kg dry weight [903].
Maximum Acceptable Concentration (MAC) trigger

(concern) concentration of cadmium for domestic

gardens and playing fields: 3-15 ppm dry weight

(London) [719].

Bureau of Land Management RMC Benchmarks, 1995:

Risk Management Criteria (RMC) were developed for

the mostly dry BLM lands in the western U.S. These

risk management criteria should be used by the land

manager as a cautionary signal that potential

health hazards are present and that natural

resource management or remedial actions are needed

[715]. Exceedances of the criteria should be

interpreted as follows [715]:

 Less than criteria: low risk

 1-10 times the criteria: moderate risk

10-100 times the criteria: high risk

>100 times the criteria: extremely high

risk

Human RMC criteria for cadmium in soil. These

categories of humans not exposed to soil with

concentrations of cadmium exceeding the below

RMCs are not expected to experience adverse

toxic effects [715]:

 Child resident (living on properties

adjacent to BLM lands): 2 mg/kg

 Camp host: 52 mg/kg

Child Camper: 36 mg/kg

ATV Driver: 726 mg/kg

Worker: 77 mg/kg

Surveyor: 774 mg/kg

Soil.Misc. (Other Non-concentration Soil Information):

Cadmium toxicity to plants is moderate [951].

Soils generally function as a major sink for most of the

cadmium released into the terrestrial environment [748].

Soils which are located close to urban areas, major

roadways, arable fields, or point sources (such as

smelter, incinerators, and power plants) generally

receive large inputs of pollutant cadmium. The

technology for decontaminating such soil has yet to be

developed [748].

Tissue and Food Concentrations (All Tissue Data Interpretation

Subsections Start with "Tis."):

Tis.Plants:
A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Plants:

Cadmium is generally less toxic to plants than to

consumers, thus cadmium accumulation in plants

represents a potential pathway to herbivorous

wildlife [699].

Aquatic macrophytes can accumulate cadmium and may

act as a source of cadmium to grazing herbivores

such as moose. This possible link stirred up

concern about elevated levels of cadmium in moose

tissues from acidified areas for human consumption

[838].

B) Body Burden Residues in Plants: Typical, Elevated, or

of Concern Related to the Well-being of the Organism

Itself:

Cadmium levels in filamentous algae (Cladophora

glomerata) were 1.4 to 3.9 ug/g dry weight.

Cadmium levels in macrophytes ranged from 0.1 to 16

ug/g dry weight from Ontario lakes of various

cadmium contamination [838].

Plant tissue concentrations of cadmium at the

Smelter Hill site (Upper Clark Fork Superfund Site

Area, Montana) averaged 2.35 ppm. Nationwide

levels of cadmium in plants are generally less than

1 ppm (Kabata-Pendias and Pendias, 1984 as cited in

PTI, 1991a) [379,699]. Cadmium is generally less

toxic to plants than to consumers, thus cadmium

accumulation in plants represents a potential

pathway to herbivorous wildlife [699].

See also [748] info in Soil.Plants section above.

Tis.Invertebrates:

A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Invertebrates:

Earthworms from a golf course which used composted

sewage sludge contained 48 ppm dry wt. cadmium.

When fed to quail as 50% of their diet, the quail

accumulated 14-18 ppm dry weight in their kidneys,

levels well above what would be expected in control

quail [347]. 

B) Concentrations or Doses of Concern in Food Items

Eaten by Invertebrates:

No information found.
C) Body Burden Residues in Invertebrates: Typical,

Elevated, or of Concern Related to the Well-being of the

Organism Itself:

Studies report cadmium levels of 3.8 to 7.3 ug/g

dry weight in cladoceran zooplankton from Lake

Huron [838]. Benthic mollusks accumulated higher

levels of cadmium in their hepatopancreas and

digestive tract than in their exoskeleton,

abdominal muscles, or viscera. Cadmium

concentrations in mollusks in Ontario ranged from

1.0 to 51.3 ug/g dry weight. Cadmium

concentrations in the amphipod Hyalella azteca

ranged from 0.13 to 56.6 ug/g dry weight in 69

Ontario lakes. Tissue cadmium concentrations were

positively correlated with aqueous cadmium levels

and inversely related to water calcium and

dissolved organic carbon levels [838].

Earthworms concentrate this metal more than most

other metals relative to soil concentrations.

Concentrations of cadmium as high as 100 ppm (dry

weight, a hazardous level for wildlife that eat

worms) were detected in earthworms from soil

containing only 2 ppm cadmium [179].

The following information summarizes data gathered

from the NOAA National Status and Trends (NS&T)

Program for the year 1990 [697]:

For cadmium in mussels and oysters combined

(n=214), the Geometric Mean was 2.7 ug/g dry

and the "high" concentration was 5.7 ug/g dry

weight [697]. NOAA "high" concentrations are

equal to the geometric mean plus one standard

deviation on the log normal distribution

[696].

Tis.Fish:

A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Fish (Includes FDA Action Levels for

Fish and Similar Benchmark Levels From Other Countries):

Legal Limits for Concentrations in Fish and Fishery

Products: The lowest legal limit was 0.0 mg/kg

(Venezuela) [216,418]. Six countries have limits

less than or equal to 0.5 mg/kg, but the U.S.

apparently has no limit [216,418].

Bureau of Land Management RMC Benchmarks, 1995:

Risk Management Criteria (RMC) were developed for

the mostly dry BLM lands in the western U.S. These
risk management criteria should be used by the land

manager as a cautionary signal that potential

health hazards are present and that natural

resource management or remedial actions are needed

[715]. Exceedances of the criteria should be

interpreted as follows [715]:

 

Less than criteria: low risk

1-10 times the criteria: moderate risk

10-100 times the criteria: high risk

>100 times the criteria: extremely high

risk

Human RMC criteria for cadmium in fish

consumed by humans: These categories of

humans not exposed to fish with concentrations

of cadmium exceeding the below RMCs are not

expected to experience adverse toxic effects

[715]:

Child resident (living on properties

adjacent to BLM lands): 78 ug/kg

Camp host: 161 ug/kg

Child Camper: 444 ug/kg

EPA Region 3 Risk Based Concentration (RBC) in fish

Tissue: 0.68 mg/Kg [903]. 

B) Concentrations or Doses of Concern in Food Items

Eaten by Fish:

No information found.

C) Body Burden Residues in Fish: Typical, Elevated, or of

Concern Related to the Well-being of the Organism Itself:

Cadmium concentrations in various freshwater fish

species from Canada were generally less than 0.4

ug/g. Cadmium concentrations in edible salmonid

tissue from Lake Ontario ranged from 0.04 to 0.21

ug/g dry weight [838].

Predator Protection Level (Tissue Concentrations):

Cadmium whole-body levels above 0.5 mg/kg are

considered to be harmful to fish and predators

[20]. 

Edible Fish Tissue (Usually Fillet) Concentrations:

The highest concentrations of cadmium in 5

studies of edible fish tissues in several

states was 5.34 mg/kg wet weight [57]. The

highest level in all but one of these 5

studies was 1.70 mg/kg wet weight [57].
Mean NCBP Levels (Tissue Concentrations): The

geometric mean of (wet-weight) whole-body

concentrations of fish in national surveys (1976-

1984) was 0.03 mg/kg cadmium [23,384].

Eisler suggested that cadmium residues in

vertebrate kidney or liver that exceed 10 ppm

(ug/g) fresh (wet) weight or 2 ppm (ug/g) whole

body fresh (wet) weight should be viewed as

evidence of probable cadmium contamination [379].

However, it is harder to find concern levels for

muscle or fatty tissue samples. Residues of 200

ppm (ug/g) fresh (wet) weight kidney, or more than

5 ppm (ug/g) whole body fresh (wet) weight are

probably life-threatening to the organism [379]. 

One author has stated that reproductive problems in

fish may occur when tissue concentrations exceed

0.1 mg/kg [57], but it is not clear from the

citation which kinds of tissues were meant. The

same paper discussed both whole body and edible

tissue data in a nearby section. 

Tissue Concentrations in Texas: The geometric mean

of whole-body cadmium concentrations in fish in a

1980-1981 national survey was 0.03 mg/kg [23], a

level exceeded in 24 of 77 Trinity River samples.

Included in this group were a large variety of

fish, turtle, and clam species. However, since

this group included a variety of non-fish samples,

it is not directly comparable to the NCBP means for

fish only. None of the samples above 0.03 mg/kg

were from the control/reference site. A Trinity

River (Texas) sample from a polluted site exceeded

0.5 ppm: a composite whole-body sample of

mosquitofish was 0.71 mg/kg wet weight.

Gradient Monitoring Levels: Cadmium showed a

general tendency to increase from upstream to

downstream in Trinity River mosquitofish. The same

trend was shown in sediment samples in a 1977 study

by the Texas Water Quality Board. Elevated

concentrations of cadmium have been found in

sediments from downstream of Dallas [42,74].

Sediments from Beltline Road (6.5 miles downstream

of our site 11) were 12.0 mg/kg, the highest

recorded in the State at that time [74]. The

highest levels of cadmium (7.0 to 12.0 mg/kg) were

found in sediment samples from sites 9 through 12

(using our site numbers), with much lower

concentrations upstream [74]. In Trinity River

study, the two highest concentrations of cadmium in

mosquitofish were both from suburban creek sites

(sites 17 and 20) [201]. Cadmium was the only
contaminant for which this was true. 

Tis.Wildlife: Terrestrial and Aquatic Wildlife, Domestic

Animals and all Birds Whether Aquatic or not:

A) As Food: Concentrations or Doses of Concern to Living

Things Which Eat Wildlife, Domestic Animals, or Birds:

No information found.

B) Concentrations or Doses of Concern in Food Items

Eaten by Wildlife, Birds, or Domestic Animals (Includes

LD50 Values Which do not Fit Well into Other Categories,

Includes Oral Doses Administered in Laboratory

Experiments):

Predator Protection Level (Tissue Concentrations):

Cadmium whole-body levels above 0.5 mg/kg are

considered to be harmful to fish and predators

[20]. 

Concentrations of cadmium as high as 100 ppm (dry

weight, a hazardous level for wildlife that eat

worms) were detected in earthworms from soil

containing only 2 ppm cadmium [179].

Dietary studies (using oral doses high enough to

cause relatively quick toxicity) feeding cadmium

chloride to a bird species, place it in the

"slightly toxic" category for quick (acute)

toxicity [185]. However, much lower levels may be

a problem for long-term (chronic) exposure.

In rats, oral doses of 40 mg cadmium/kg body weight

per day as cadmium chloride given on days 6-19 of

gestation increased fetal resorption and caused

skeletal, kidney, and heart abnormalities in

fetuses, stillborn, and offspring. The incidence

and intensity of skeletal defects increased with

cadmium dosage, but the renal and cardiac

abnormalities were not dose-related. /Inorganic

cadmium/ [Venugopal, B. and T.D. Luckey. Metal

Toxicity in Mammals, 2. New York: Plenum Press,

1978. 83].

Oak Ridge National Lab, 1994: Risk Assessment

Screening Benchmarks for Wildlife derived from NoObserved-Adverse-Effect (NOAEL) levels (mg

contaminant per kg body weight per day). To be

considered unlikely to represent an ecological

risk, wet-weight field concentrations should be

below the following (right column) benchmarks for

each species present at the site [650]:
 CAS 7440-43-9, CADMIUM (AS SOLUBLE SALT) 

 NOAEL FOOD CONCENSPECIES (mg/kg/day) TRATION (ppm)

Mouse 0.19130 0.00000

 (test species)

Short-tailed Shrew 0.24000 0.40100

Little Brown Bat 0.30200 0.90700

White-footed Mouse 0.21200 1.37100

Meadow Vole 0.16900 1.48400

Cottontail Rabbit 0.05700 0.28700

Mink 0.06000 0.43900

Red Fox 0.03700 0.36600

Whitetail Deer 0.01600 0.51600

Comment: Actually, the number of

significant figures for a benchmark value

should never be more than one; even if

these values have been taken directly

from another report, they should be

rounded; otherwise the impression is

given of a level of accuracy that is

simply unwarranted. The uncertainties are

too large to justify such a fine

distinction (Owen Hoffman, SENES Oak

Ridge, Personal Communication, 1997).

Apparently protected from the deleterious effects

of high metal body burdens by metallothioneins,

birds and mammals are comparatively resistant to

the biocidal properties of cadmium [379]. For

example, adult drake mallards fed up to 200 ppm

cadmium in the diet for 90 days all survived with

no loss of body weight (kidney cadmium exceeded 130

ppm fresh (wet) weight under this regimen). Ducks

contained the highest levels of metallothioneins of

all groups examined. The lowest oral dose

producing death was 250 mg/kg body weight of

cadmium (as fluoroborate) in rats, and 150 mg/kg

body weight of cadmium (as cadmium fluoride) in

guinea pigs [379].

C) Body Burden Residues in Wildlife, Birds, or Domestic

Animals: Typical, Elevated, or of Concern Related to the

Well-being of the Organism Itself:

It has been suggested that cadmium concentrations

in vertebrate kidney and liver exceeding 10 ug/g

wet weight may be viewed as evidence of cadmium

contamination, and residues exceeding 200 ug/g may

be viewed as life threatening [379,838]. However,

significant accumulation of cadmium has been

demonstrated in wildlife, particularly birds,

remote from point sources of contamination. For

example, cadmium levels in several species of
seabirds from the south Atlantic Ocean contained up

to 112 ug/g wet weight in their kidneys [838].

Eisler suggested that cadmium residues in

vertebrate kidney or liver that exceed 10 ppm

(ug/g) fresh (wet) weight or 2 ppm (ug/g) whole

body fresh (wet) weight should be viewed as

evidence of probable cadmium contamination [379].

However, it is harder to find concern levels for

muscle or fatty tissue samples. Residues of 200

ppm (ug/g) fresh (wet) weight kidney, or more than

5 ppm (ug/g) whole body fresh (wet) weight are

probably life-threatening to the organism [379]. 

In one study where the soil contained 6.0 ppm

cadmium, earth worms contained 79 ppm dry weight

cadmium, moles had 294 ppm dry weight in their

kidneys and 227 ppm in their livers [347]. 

In another study, earthworms from a golf course

which used composted sewage sludge contained 48 ppm

dry wt. cadmium. When fed to quail as 50% of their

diet, the quail accumulated 14-18 ppm dry weight in

their kidneys, levels well above what would be

expected in control quail [347]. 

Earthworms concentrate this metal more than most

other metals relative to soil concentrations. This

is one potential hazard of birds feeding on sewage

sludge amended soils [179]. 

A Trinity River (Texas) sample which exceeded 0.5

ppm included a fatty tissue sample (0.65 mg/kg wwt)

from a composite sample of three Mississippi map

turtles [201]. 

The average kidney cadmium level in deer collected

less than 8 km from a Pennsylvania zinc smelter was

310 ug/g dry weight compared with 15.5 ug/g dry

weight in deer collected more than 100 km from the

smelter. One deer with a renal cadmium level of

600 ug/g dry weight had lesions in joints, similar

to those observed in nearby horses diagnosed as

suffering from zinc poisoning [838].

Studies report cadmium-induced lesions in tissues

of the common shrew trapped near a copper/cadmium

alloying factory. Tissue cadmium concentrations

ranging from 300 to 1000 ug/g dry weight in liver,

and 150 to 560 ug/g dry weight in kidney are among

the highest recorded in terrestrial wildlife [838].

For information on alligator residues of cadmium,

see: Delany, M.F., J.U. Bell, and S.F. Sundlof.
1988. Concentrations of contaminants in muscle of

the American alligator in Florida. J. Wildl. Dis.

24:62-66. Florida Game and Fresh Water Fish Comm.,

Wild. Res. Lab., 4005 South Main St., Gainesville,

FL 32601.

Tis.Human:

A) Typical Concentrations in Human Food Survey Items:

No information found.

B) Concentrations or Doses of Concern in Food Items

Eaten by Humans (Includes Allowable Tolerances in Human

Food, FDA, State and Standards of Other Countries):

Crit. Dose: 0.005 mg/kg-day [Study 1 NOAEL] UF: 10

MF: 1 [893]. 

RfD: 5E-4 mg/kg-day Confidence: High [893]. 

EPA Region 3 Risk Based Concentration (RBC) in fish

Tissue: 0.68 mg/Kg [903]. 

See also Tis.Fish, A) section above.

NOTE: Because of the highly selected

accumulation of cadmium in the visceral organs

(that is, internal organs), the animal body,

in general, tends to serve as a filter for

cadmium transfer to human foods [748]. With

the exception of liver, humans tend to eat

more muscle tissues than visceral organs.

C) Body Burden Residues in Humans: Typical, Elevated, or

of Concern Related to the Well-being of Humans:

 Information from the HSDB [366]:

To assess the pathophysiologic significance of

increased body burdens of cadmium (Cd), crosssectional evaluation of renal function and calcium,

phosphorus and vitamin D metabolism was carried out

in 38 industrial workers exposed to Cd for 11-37

yr. Average airborne concentrations of Cd ranged

from 5 - 229 ug/cu m. Mean kidney Cd burden was 7.4

+/- 4.4 mg in nonsmokers and 12.3 +/- 7.2 mg for

smokers. Mean liver Cd in nonsmokers was 4.5 +/-2.6

ug/g and 7.9 +/-4.9 ug/g in smokers. Liver or

kidney Cd burden was considered elevated in 31% of

the workers. Creatinine clearance was normal in all

workers. Maximal urinary concentrating ability was

abnormal in a significant fraction (52%) of the
men. [Greenberg A et al; Arch Environ Health 41

(2): 69-76 (1986)].

In man/ about half of total body burden is found in

liver & kidneys. Cadmium in these organs is mainly

bound to a low molecular weight protein, in form of

a metallothionein [IARC. Monographs on the

Evaluation of the Carcinogenic Risk of Chemicals to

Man. Geneva: World Health Organization,

International Agency for Research on Cancer, 1972-

1985. (Multivolume work).,p. V2 90 (1973)].

Tis.Misc. (Other Tissue Information):

Elevated cadmium concentrations have been reported in

lower trophic levels in acidified lakes [838]. This had

led to speculation that piscivorous or predatory animals

could be exposed to higher cadmium concentrations in

acidified watersheds. Studies in the U.S., Canada, and

Sweden report that lake cadmium concentrations were

inversely correlated with lake pH. An inverse

relationship between cadmium concentrations and lake pH

has been observed for yellow perch, bluegill sunfish,

suckers, and various invertebrate species [838].

Bio.Detail: Detailed Information on Bioconcentration,

Biomagnification, or Bioavailability:

Preliminary data suggests the potential for bioaccumulation or

bioconcentration of cadmium is high for the following biota:

mammals, birds, fish, mosses, lichens, algae, mollusks, crustacea,

lower animals, and higher plants [83]. The best potential mediums

for biological monitoring appear to include animal hair, clams,

algae, mosses, lichens, and higher plants [83]. In fish, cadmium

accumulates in the gill, liver, and kidney [488,838]. Irwin found

mosquitofish to be acceptable for gradient monitoring of cadmium

[201].

Cadmium accumulates in microorganisms, plant tissue, and

animal tissue. Median bioconcentration factors for cadmium in

macrophytes are less than 50 times, and generally less than 100

times for fish. Whole-body bioconcentration factors for foodexposed rainbow trout and whitefish are less than one.

Bioconcentration factors of 900 to 4000 are reported in some

mollusks [838,849]. It is generally reported that although cadmium

accumulates in freshwater organisms, it does not biomagnify in the

food chain [838].

Because of the highly selected accumulation of cadmium in the

visceral organs (that is, internal organs), the animal body, in

general, tends to serve as a filter for cadmium transfer to human

foods [748]. With the exception of liver, humans tend to eat more

muscle tissues than visceral organs.

Cadmium is sequestered in metallothionein complexes [838].

The metallothionein compounds have a high proportion of sulfur-
containing amino acids that bind with cadmium such that it becomes

unavailable for interaction with intracellular receptor sites.

Tissue accumulation and distribution of cadmium is dependent upon

the route of exposure (food or water vector) [838]. 

For information on cadmium in sediments vs. AVS and SEM, see

Sed.Misc. section.

 Earthworms versus Cadmium:

Earthworms concentrate this metal more than most other metals

relative to soil concentrations. This is one potential hazard

of birds feeding on sewage sludge amended soils [179].

Concentrations of cadmium as high as 100 ppm (dry weight, a

hazardous level for wildlife that eat worms) were detected in

earthworms from soil containing only 2 ppm cadmium [179].

In one study where the soil contained 6.0 ppm cadmium, earth

worms contained 79 ppm dry weight cadmium, moles had 294 ppm

dry weight in their kidneys and 227 ppm in their livers [347].

In another study, earthworms from a golf course which used

composted sewage sludge contained 48 ppm dry wt. cadmium.

When fed to quail as 50% of their diet, the quail accumulated

14-18 ppm dry weight in their kidneys, levels well above what

would be expected in control quail [347]. 

The concentration factor for cadmium in earthworms relative to

soils containing a few ppm is 21; however, it takes a while

for the cadmium to build up in the worms, so short-term

experiments may give misleading results [347].

Interactions:

The mobility and bioavailability of cadmium in aquatic

environments is enhanced under conditions of low pH, low hardness,

low suspended matter levels, high redox potential, and low salinity

[907]. Some recent research (1990) has focused on the tendency of

low-alkalinity (less than 50 ueq/L) waters to have a relatively

high potential for acid deposition effects and increased

bioaccumulation of cadmium in fish [383]. See also the Bio.Detail

section below.

For information on cadmium in sediments and bioconcentratrion

vs. AVS and SEM, see Sed.Misc. section.

 Water hardness is governed by calcium and magnesium salts

combined with bicarbonate and carbonate. Cadmium toxicity is

moderated at increasing water hardness by either (1) complexation

with carbonate, or (2) competition with calcium ions [838]. Low

water pH also reduced cadmium toxicity to algae and to fish in some

studies. It is suggested that the reduced toxicity is due to

competition between H+ ions and free metal cations for transport

mechanisms or cellular binding sites [838].

Studies suggest that humic acid or other complexing materials

have a varying effect on cadmium toxicity [838]. The presence of

complexing materials in water decreased cadmium uptake and toxicity
in fish, but had mixed effects on toxicity to invertebrates.

Monthly tests demonstrated that cadmium toxicity in river water

varied by a factor of three or more over the year due to

fluctuating levels of suspended solids [838].

Soil pH is particularly important in determining the amount of

cadmium taken up from the soils [748]. A reduction in pH often

enhances the cadmium uptake by plants. Other physicochemical

properties of soils that affect the uptake of cadmium by crops

include 1) the oxidation-reduction potential of soils, 2) soil

temperature, 3) clay content and cation exchange capacity, 4)

concentrations of iron, manganese, and aluminum oxides and

hydroxides, 5) presence of anions that can immobilize the cadmium,

6) organic matter concentration, and 7) interactive effects of

zinc, copper, nickel manganese, and selenium [748].

Female Swiss mice were exposed to cadmium in the drinking

water at concentrations ranging from 0 to 50 ppm for 105 or 280 day

time periods. In the 105 day study, the effect of cadmium on

urethan induced pulmonary adenoma formation was evaluated. Urethan

induced sleeping times observed following ip injection of urethan

after 3 weeks of cadmium exposure were not affected by cadmium

indicating that chronic cadmium exposure did not alter the

elimination of urethan. Pulmonary adenoma formation which was

evaluated 84 days later was not affected by cadmium. The size and

number of tumors remained unchanged. Immunosuppressive actions of

cadmium do not influence urethan induced adenoma formation. In the

280 day study the effects of cadmium on the incidence of

spontaneous murine lymphocytic leukemia was evaluated. Mice exposed

to 10 or 50 ppm cadmium experienced 33% more deaths from the virus.

The average time till death was unaffected. Immunosuppressive

effects of cadmium impair immunosurveillance mechanisms that

control expression of the murine lymphocytic leukemia virus.

(Blakely BR; Appl Toxicol 6, 6: 425-9, 1986) [366].

Cadmium and zinc are often found together (see Uses/Sources

section).

Information on cadmium + zinc from 1994 National Society of

Risk Assessment Annual Meeting Paper Entitled "An Evaluation of

Potential Interactions of Zinc and Cadmium at a Former Zinc Smelter

Site." by authors G. Evans, R. A. Schoof and L. Keill, PTI

Environmental Services, Bellevue, WA: 

Extensive literature is available regarding the protective (or

antagonistic) effects of zinc on cadmium toxicity.

Simultaneous administration of zinc with cadmium has been

found to protect against several aspects of cadmium toxicity,

including proteinuria, the critical effect used as the basis

for the cadmium oral reference doses (RfDs). The potential for

interactions between cadmium and zinc is of particular

significance at sites where increased environmental

concentrations of zinc are found in conjunction with increased

concentrations of cadmium...Animal studies provide strong

evidence that potential antagonistic interactions between zinc

and cadmium at the site may protect against the toxic effects

of cadmium. However, available data from studies on various

human populations supporting the derivation of the cadmium
RfDs appear insufficient to determine the extent to which

antagonism of cadmium toxicity by zinc may have occurred in

these populations. Consequently, it was concluded that

although zinc exposures at the site may be protective of

potential cadmium toxicity, there are currently insufficient

data to support any quantitative change in the assessment of

cadmium toxicity at the site. 

Uses/Sources:

Cadmium has been used in preparation of embalming fluids

[490]. Thus, like arsenic, it is one contaminant to look for

around old cemeteries (see arsenic entry). It is also used in

engraving [490].

Cadmium is used in metal plating and in batteries [335]. Air

pollution sources of cadmium include smelters, incinerators, oil

furnaces, and coal combustion. About 75% of all cadmium produced

is used for cadmium plating of easily corroded metals such as iron

and steel [333]. Metal platers, scrap yards, batteries, television

tubes, solar cells, fungicides, and various industrial discharges

constitute additional sources [57]. Because of its low melting

point, cadmium is used in special alloys such as aluminum solder

(40% cadmium, 50% lead, 10% tin); Wood's metal (50% bismuth, 25%

lead, 15% cadmium, 10% tin), which has a melting point of 70 deg C;

and related alloys that are used, for example, in sprinkler

installations and other fire-protection systems [333]. In some

localities, significant amounts of cadmium are also present in

sewage sludges [61,94] and in leachates from municipal landfills

[46,80]. 

Cadmium is also used in nickel-cadmium batteries, to absorb

neutrons in the control rods and shielding of nuclear reactors, and

in the manufacture of artists' pigments, automobile enamels, vinyl

plastics, and phosphors for color television tubes [333]. 

Cadmium compounds (the metal does not occur naturally in the

free state) are almost always found together with zinc compounds,

so that the two metals are always mined together [333].

Plants take up cadmium from soil, groundwater, sewage sludge,

biocides, and air pollution [83]. Animals take up cadmium from

drugs, biocides, industrial sources, contaminated water, and

contaminated food [83].

 Major Uses [940]:

1. In electroplating of automotive, aircraft & electronic

parts; marine equipment & industrial machinery; in prepn of

cadmium sulfides, cadmium selenides & mixt containing these

salts for use as pigments (incl phosphors) [IARC. Monographs

on the Evaluation of the Carcinogenic Risk of Chemicals to

Man. Geneva: World Health Organization, International Agency

for Research on Cancer,1972-PRESENT. (Multivolume work).,p.

V11 44 (1976)].

2. As soft solder & solder for aluminum; deoxidizer in nickel
plating; process engraving; photometry of uv sun-rays; in

electrodes for cadmium vapor lamps, photoelectric cells [The

Merck Index. 10th ed. Rahway, New Jersey: Merck Co., Inc.,

1983. 223].

3. In fire protection systems, machinery enamels, baking

enamels; weston standard cell; photography & lithography; mfr

fungicide [Sax, N.I. and R.J. Lewis, Sr., eds.,. Hawley's

Condensed Chemical Dictionary. 11th ed. New York: Van Nostrand

Reinhold Co., 1987. 196].

4. Plating & coating agent-eg, for transportation equipment

[SRI].

5. Component of batteries-eg, nickel-cadmium batteries [SRI].

6. Chem int for plastic stabilizers-eg, cadmium stearate

[SRI].

7. Component of alloys-eg, for bearings & control rods [SRI].

8. Analytical reagent-eg, for determination of nitrate [SRI].

9. Chem int for other cadmium cmpds-eg, cadmium chloride

[SRI].

10. A constituent of easily fusible alloys, eg, lichtenberg's,

abel's, lipowitz', newton's, and wood's metal. [The Merck

Index. 10th ed. Rahway, New Jersey: Merck Co., Inc., 1983.

223].

11. In low-melting alloys. [ITII. Toxic and Hazarous

Industrial Chemicals Safety Manual. Tokyo, Japan: The

International Technical Information Institute, 1982. 95].

12. In brazing alloys. [ITII. Toxic and Hazarous Industrial

Chemicals Safety Manual. Tokyo, Japan: The International

Technical Information Institute, 1982. 95].

13. In solar ... batteries. [ITII. Toxic and Hazarous

Industrial Chemicals Safety Manual. Tokyo, Japan: The

International Technical Information Institute, 1982. 95].

14. In television phosphors. [ITII. Toxic and Hazarous

Industrial Chemicals Safety Manual. Tokyo, Japan: The

International Technical Information Institute, 1982. 95].

15. Neutron absorber in nuclear reactors. [Sittig, M. Handbook

of Toxic And Hazardous Chemicals. Park Ridge, NJ: Noyes Data

Corporation, 1981. 119].

16. Stabilizer for polyvinyl chloride. [Sittig, M. Handbook of

Toxic And Hazardous Chemicals. Park Ridge, NJ: Noyes Data

Corporation, 1981. 119].
17. Amalgam in dentistry. [Sittig, M. Handbook of Toxic And

Hazardous Chemicals. Park Ridge, NJ: Noyes Data Corporation,

1981. 119].

18. Charging Jones reactors. [Sittig, M. Handbook of Toxic And

Hazardous Chemicals. Park Ridge, NJ: Noyes Data Corporation,

1981. 119].

 Natural Sources [940]:

1. Coal and other fossil fuels contain cadmium and their

combustion releases the element into the environment. [Gilman,

A.G., L.S.Goodman, and A. Gilman. (eds.). Goodman and Gilman's

The Pharmacological Basis of Therapeutics. 7th ed. New York:

Macmillan Publishing Co., Inc., 1985. 1617].

2. Occurs in a greenockite (cadmium sulfide) ore containing

zinc sulfide also with lead and copper ores containing zinc.

/Found/ in Canada, central and western USA, Peru, Australia,

Mexico and Zaire. [Sax, N.I. and R.J. Lewis, Sr. (eds.).

Hawley's Condensed Chemical Dictionary. 11th ed. New York: Van

Nostrand Reinhold Co., 1987. 196].

3. The principal cadmium-bearing mineral in primary deposits

is sphalerite which also contains zinc. [Nat'l Research

Council Canada; Cadmium p.16 (1979) NRCC No. 16743].

4. Among sedimentry rock types, the carbonaceous shales,

formed under the reducing conditions, contain the most

cadmium. [Nat'l Research Council Canada; Cadmium p.16 (1979)

NRCC No.16743].

5. Cadmium content: Peat: <1-3 ppm based on 10 samples; Coal:

<1-20 ppm based on 12 samples; bitumens, solid hydrocarbons,

asphalts <1-3 ppm based on 6 samples. [Nat'l Research Council

Canada; Cadmium p.30 (1979) NRCC No.16743].

6. Cadmium concentrations in: phosphatic rock: up to 100

mg/kg; igneous rock: 0.001 mg/kg. [Korte F; Ecotoxicol Environ

Safety 7 (1): 3-8 (1983)].

7. Volcanic action is considered to be the major natural

source of cadmium. This is related to the very large

quantities of particulate matter emitted, together with high

enrichment of cadmium in volcanic aerosols. An investigation

into trace element emissions from Mount Etna in Sicily

estimated that 2.8 x 10-2 tons/day, or about 10 tons/year of

cadmium was discharged into the atmosphere. [Baut-Menard P,

Arnold M; Geophys Res Lett 5: 245-248 (1978)].

8. Cadmium content /in/: sphalerite: 0.0001-2%; greenockite:

77.8%; hawleyite: 77.8%; chalcopyrite: < 0.4-110 ppm;

marcasite: <0.3-<50 ppm; arsenopyrite: < 5 ppm; galena: < 10-

3000 ppm; pyrite: < 0.06-42 ppm; pyrrhotite: trace;
tetrahedrite: 80-2000 ppm; magnetite: 0-0.31 ppm; cadmium

oxide: 87.5%; limonite: <5-1000 ppm; wad and manganese oxides:

<10-1000 ppm; anglesite: 120- >1000 ppm; barite: < 0.2 ppm;

anhydrite and gypsum: < 0.2 ppm; calcite: < 1-23 ppm;

smithsonite: 0.1-2.35%; otavite: 65.18%; pyromorphite: < 1-8

ppm; scorodite: <1-5.8 ppm; beudantite: 100-1000 ppm; apatite:

0.14-0.15 ppm; bindheimite: 100-1000 ppm; silicates: 0.03-2.8

ppm. [Nat'l Research Council Canada; Cadmium p.17 (1979) NRCC

No.16743].

 Artificial Sources [940]:

1. Liberation during smelting and refining of ores where it is

a by-product of zinc, lead and copper-bearing ores. Liberation

during recovery of metal by processing scrap; during melting

and pouring of cadmium metal; during casting of alloys for

cadmium-copper, cadmium-lead, cadmium-bismuth, cadmium-silver,

cadmium-nickel, cadmium-lead-silver, cadmium-lead-silvernickel, cadmium-lead-bismuth-tin, and cadmium-gold 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 jewlery. Liberation during fabrication of metal,

alloys, or plated steel. Liberation 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 synthesis. Liberation

during coating on metals by hot dipping or spraying.

Liberation 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. /Cadmium, cadmium oxide/ [Mackison, F. W.,

R. S. Stricoff, and L. J. Partridge, Jr. (eds.). NIOSH/OSHA -

Occupational Health Guidelines for Chemical Hazards.

DHHS(NIOSH) PublicationNo. 81-123 (3 VOLS). Washington, DC:

U.S. Government Printing Office, Jan. 1981. 3].

2. All of the cadmium and/or its salts ... Used as stabilizers

and pigments in plastics could enter the environment, a

process particularly facilitated by incineration. Thus,

disposal of plastics could contribute to pollution by cadmium.

[IARC. Monographs on the Evaluation of the Carcinogenic Risk

of Chemicals to Man. Geneva: World Health Organization,

International Agency for Research on Cancer,1972-PRESENT.

(Multivolume work).,p. V11 50 (1976)].

3. Ceramic artists can be exposed to many hazardous materials,

generally related to dry clays, glazes and kiln use. Glazes

can contain lead, antimony, arsenic, barium, beryllium, boron,

chromium, cobalt, cadmium, copper, vanadium and other

materials which all have potential toxic effects. [Hart C; J

Environ Health 49 (5): 282-86 (1987)].
4. Forms readily from contact of cadmium vapor with air ...

Found where cadmium is present in emissions from thermal

processes / [IARC. Monographs on the Evaluation of the

Carcinogenic Risk of Chemicals to Man. Geneva: World Health

Organization, International Agency for Research on

Cancer,1972-PRESENT. (Multivolume work).,p. V2 82 (1973)].

Forms/Preparations/Formulations:

 Cadmium forms many compounds in nature, such as:

Water-soluble compounds [907]:

Cadmium chloride

Cadmium bromide

Cadmium iodide

Cadmium nitrate

Cadmium sulfate

Water-insoluble compounds [907]:

Cadmium oxide

Cadmium sulfide

Cadmium carbonate

Cadmium orthophosphate

Cadmium fluoride

Radionuclides:

The symbol for Cadmium-109 is 109Cd, the atomic number is

48, the half-life is 462 days, and X-ray emission is the

major form of decay [674].

The symbol for Cadmium-113m is 113mCd, the atomic number

is 48, the half-life is 13.7 years, and beta emission is

the major form of decay [674].

The symbol for Cadmium-115m is 115mCd, the atomic number

is 48, the half-life is 44.6 days, and beta emission is

the major form of decay [674].

The symbol for Cadmium-115 is 115Cd, the atomic number is

48, the half-life is 54 hours, and beta emission is the

major form of decay [674].

Chem.Detail: Detailed Information on Chemical/Physical Properties:

 Melting point: 321 degrees C [907,908,940]. 

Boiling point: 767 degrees C [908]. 

Boiling Point [940]:

760... 5 DEG C [The Merck Index. 10th ed. Rahway, New
Jersey: Merck Co., Inc., 1983]. 223:

 Density: 8.65 g/cm3 at 20 degrees C [907]. 

Density/Specific Gravity [940]:

8.65 AT 25 DEG C [The Merck Index. 10th ed. Rahway, New

Jersey: Merck Co., Inc., 1983. 223].

 Solubility: Insoluble (sic) in water [849,908,940]. 

NOTE: Hardly anything is totally insoluble, just

relatively insoluble (Roy Irwin, National Park Service,

personal commuication, 1996).

 Vapor pressure: 1 mmHg at 394 degrees C [849,908,940].

 Molecular weight: 112.4 g/mol [907,908].

Color: 

Blue-white [907,908]. 

Silver-white, blue-tinged, lustrous metal; distorted

hexagonal closed-packed structure [The Merck Index. 10th

ed. Rahway, New Jersey: Merck Co., Inc., 1983. 223 [940].

Other Chemical/Physical Properties [940]:

1. MALLEABLE [Weast, R.C. (ed.) Handbook of Chemistry and

Physics, 68th ed. Boca Raton, Florida: CRC Press Inc.,

1987-1988.,p. B-78].

2. Heat capacity: 6.22 Cal/mole-deg at 25 deg c &

constant pressure; readily cut with knife [The Merck

Index. 10th ed. Rahway, New Jersey: Merck Co., Inc.,

1983. 223].

3. Tarnishes in moist air. [ITII. Toxic and Hazarous

Industrial Chemicals Safety Manual. Tokyo, Japan: The

International Technical Information Institute, 1982. 95].

4. Cadmium becomes brittle at 80 deg C. [ITII. Toxic and

Hazarous Industrial Chemicals Safety Manual. Tokyo,

Japan: The International Technical Information Institute,

1982. 95].

5. Eight stable isotopes of cadmium (Cd) are known in

nature with conventional abundances as follows: (106)Cd:

1.21%; (108)Cd: 0.88%; (110)Cd: 12.39%; (111)Cd: 12.75%;

(112)Cd: 24.07%, (113)Cd: 12.26%; (114)Cd: 28.86%;

(116)Cd: 7.58%. [Nat'l Research Council Canada; Cadmium

p.15 (1979) NRCC No.16743].

6. The electrical conductivity of cadmium is less than

that of silver or copper, but greater than that of iron.
[Chizhikov DM; Cadmium (1966) as cited in NIOSH; Criteria

Document: Cadmium p.7 (1976) DHEW Pub. NIOSH 76-192].

7. Cadmium (Cd) has two radioisotopes: (109)Cd and

(115)Cd. [Mennear JH; Cadmium Toxicity p.1 (1979)].

8. SOL IN ACID, AMMONIUM NITRATE & HOT SULFURIC ACID

[Weast, R.C. (ed.) Handbook of Chemistry and Physics,

68th ed. Boca Raton, Florida: CRC Press Inc., 1987-

1988.,p. B-78

 

Odor [940]:

1. Odorless [Mackison, F. W., R. S. Stricoff, and L. J.

Partridge, Jr. (eds.). NIOSH/OSHA - Occupational Health

Guidelines for Chemical Hazards. DHHS(NIOSH)

PublicationNo. 81-123 (3 VOLS). Washington, DC: U.S.

Government Printing Office, Jan. 1981. 1].

Corrosivity [940]:

1. Highly corrosion resistant [Sittig, M. Handbook of

Toxic And Hazardous Chemicals. Park Ridge, NJ: Noyes Data

Corporation, 1981. 119].

Spectral Properties [940]:

1. INDEX OF REFRACTION: 1.8 AT 578 NM & 20 DEG C/D [IARC.

Monographs on the Evaluation of the Carcinogenic Risk of

Chemicals to Man. Geneva: World Health Organization,

International Agency for Research on Cancer,1972-PRESENT.

(Multivolume work).,p. V11 41 (1976)].

Fate.Detail: Detailed Information on Fate, Transport, Persistence,

and/or Pathways:

For information on cadmium in sediments and bioconcentratrion

vs. AVS and SEM, see Sed.Misc. section.

 Volatilization from Water/Soil [940]:

Cadmium can enter the air from natural sources. [IARC.

Monographs on the Evaluation of the Carcinogenic Risk of

Chemicals to Man. Geneva: World Health Organization,

International Agency for Research on Cancer,1972-PRESENT.

(Multivolume work).,p. V2 79 (1973)].

 Biological Half-Life [940]:

An accumulation of cadmium occurs in many tissues and

particularly long half-times, 10-30 years, have been reported

for muscles, kidneys and liver. [Friberg, L., Nordberg, G.F.,

Kessler, E. and Vouk, V.B. (eds). Handbook of the Toxicology
of Metals. 2nd ed. Vols I, II.: Amsterdam: Elsevier Science

Publishers B.V., 1986.,p. V2 130].

 Absorption, Distribution and Excretion [366]:

Cadmium is poorly absorbed from the gastrointestinal tract ...

Absorption from the respiratory tract appears to be more

complete; cigarette smokers may absorb 10-40% of inhaled

cadmium. After absorption, cadmium is transported in blood,

bound mainly to blood cells and albumin. After distribution,

approx 50% of the total body burden is found in the liver and

kidney. [Gilman, A.G., L.S.Goodman, and A. Gilman. (eds.).

Goodman and Gilman's The Pharmacological Basis of

Therapeutics. 7th ed. New York: Macmillan Publishing Co.,

Inc., 1985. 1618].

In the blood, a small-molecular weight plasma protein known as

metallothionein binds cadmium. The elimination half-life of

cadmium is long (16-33 yr) ... [Ellenhorn, M.J. and D.G.

Barceloux. Medical Toxicology - Diagnosis and Treatment of

Human Poisoning. New York, NY: Elsevier Science Publishing

Co., Inc. 1988. 1018].

When exposure is excessive, the concentration of of cadmium in

liver may be up to 100 times greater than normal. In many

cases kidney concentrtions are very high, but when kidney

damage has occurred ... Excretion incr considerably. This

explains fact that in most severely poisoned workers ...

Kidney levels, in contrast to liver ... Are low ... /Cadmium/

[Friberg, L., G.R. Nordberg, and V.B. Vouk. Handbook on the

Toxicology of Metals. New York: Elsevier North Holland, 1979.

361].

Irrespective of mode of admin, cadmium crosses placental

barrier in pregnant rats & hamsters, as shown by detectable

amt in liver, brain & digestive tract of newborn. More than

2.5 Times the amt was found in livers of ... Test animals ...

Than in control ... However, there is efficient placental

barrier against cd in goats. [Venugopal, B. and T.D. Luckey.

Metal Toxicity in Mammals, 2. New York: Plenum Press, 1978.

78].

Blood cadmium equilibrates with any given level of exposure

within a year, while total amt in body keeps accum over a

period of decades. Much the same situation has been noted in

... Urinary excretion of cadmium. [Doull, J., C.D. Klaassen,

and M. D. Amdur (eds.). Casarett and Doull's Toxicology. 2nd

ed. New York: Macmillan Publishing Co., 1980. 431].

Significance of inhalation exposure depends on concn, particle

size, & solubility of particulate matter, & physiologic

parameters such as rate & depth of resp. [Casarett, L.J., and

J. Doull. Toxicology: The Basic Science of Poisons. New York:

MacMillan Publishing Co., 1975. 469].
About 5% of cadmium ingested by human ... Is absorbed, but

calcium and iron deficiency may incr this amount. Portion of

inhaled cadmium absorbed is dependent on particle size &

solubility. Absorbed cadmium is mainly stored in kidneys &

liver. Excretion is slow, less than 0.01% Of body burden/day.

[Friberg, L., G.R. Nordberg, and V.B. Vouk. Handbook on the

Toxicology of Metals. New York: Elsevier North Holland, 1979.

355].

When renal damage has occurred, cadmium excretion by urine

incr dramatically ... [Friberg, L., G.R. Nordberg, and V.B.

Vouk. Handbook on the Toxicology of Metals. New York: Elsevier

North Holland, 1979. 363].

In many species, including mice, rats, guinea pigs, rabbits,

dogs & monkeys, about 10-40% of cadmium is retained after

inhalation of cadmium cmpd. ... Studies in mice indicate that

less than 10% of oral dose is absorbed ... [IARC. Monographs

on the Evaluation of the Carcinogenic Risk of Chemicals to

Man. Geneva: World Health Organization, International Agency

for Research on Cancer, 1972-1985. (Multivolume work).,p. V2

87 (1973)].

(115)Cadmium was found to accumulate selectively in rat kidney

cortex. (109)Cadmium given sc to rats immediately appeared in

blood plasma & then disappeared rapidly; after 6 days only 2%

of dose was excreted in feces. [IARC. Monographs on the

Evaluation of the Carcinogenic Risk of Chemicals to Man.

Geneva: World Health Organization, International Agency for

Research on Cancer, 1972-1985. (Multivolume work).,p. V2 87

(1973)].

Excretion via feces of normal humans is about 30-50 ug/day.

Retention of ingested cadmium varied between 4.7-7% In five

adult men. Only very small proportion of daily absorbed dose

will be excreted ... Normal urinary excretion in humans ... 1-

2 UG PER DAY. [IARC. Monographs on the Evaluation of the

Carcinogenic Risk of Chemicals to Man. Geneva: World Health

Organization, International Agency for Research on Cancer,

1972-1985. (Multivolume work).,p. V2 89 (1973)].

In mammals, cadmium will accumulate especially in liver &

kidneys ... Studies in mice using aerosols of cadmium cmpd

showed that particles of less than 2 microns were found in

lungs & were also absorbed & concentrated in kidneys. [IARC.

Monographs on the Evaluation of the Carcinogenic Risk of

Chemicals to Man. Geneva: World Health Organization,

International Agency for Research on Cancer, 1972-1985.

(Multivolume work).,p. V2 87 (1973)].

After a yr of feeding 1 ppm cadmium (Cd) (as cadmium sulfate

or cd contained in roll shell liver) in calcium-deficient diet

of female rats, accum rate in liver & kidney was 0.33-0.48%,

Whereas that of water-sol cd compd & cd fed as cd-polluted
rice was 0.43-0.57%. [Sakamoto M; Juzen Igakkai Zasshi 83 (4):

533 (1974)].

Cadmium (Cd) concn in blood & urine of exposed & non-exposed

workers was measured. Significant pos correlation observed.

Concn in blood related to environ cd over 30 mug/cu m of

exposure. Over 6 mo exposure to same level suddenly incr cdurine excretion. [kono K ET AL; Proc Int Congr Occup Health

19th 1 (Chem Hazards): 207 (1980)].

Absorption of cadmium from soils by rice plants incr with incr

solubility of cadmium cmpd, in order of: cadmium chloride

being more sol than cadmium nitrate followed by cadmium oxide,

cadmium carbonate, metallic cadmium, cadmium hydroxide,

cadmium phosphate, cadmium sulfate. Calcium silicate plus

phosphate prevented cadmium absorption. [Ueta H et al;

Tottori-ken Nogyo Kenkyu Hokoku 13: 17 (1973)].

Cadmium accumulates in the liver and kidneys, perhaps because

these two organs contain low molecular weight (about 10,000

daltons) proteins called metallothionein. [Gosselin, R.E.,

R.P. Smith, H.C. Hodge. Clinical Toxicology of Commercial

Products. 5th ed. Baltimore: Williams and Wilkins, 1984.,p.

III-78].

The absorption of cadmium cmpd through skin is negligible, the

main routes of exposure for humans being via respiration and

ingestion. Between 10 and 50% of inhaled cadmium will be

absorbed, the absorption being greater for small particles and

fumes than for large particle dust. In humans, about 5% of

ingested cadmium is absorbed. A low intake of calcium or iron

increases absorption. In individuals with iron deficiency, the

gastrointestinal absorption rate may be as high as 20%.

[Friberg, L., Nordberg, G.F., Kessler, E. and Vouk, V.B.

(eds). Handbook of the Toxicology of Metals. 2nd ed. Vols I,

II.: Amsterdam: Elsevier Science Publishers B.V., 1986.,p.

VII-130].

Nonradioactive and radioactive metal salts were administered

intravenously to Sprague Dawley rats. The highest amount of

each metal approached the maximum tolerated dose. Cobalt (Co),

silver (Ag), and manganese (Mn) were eliminated rapidly. The

elimination of 20 to 50% of the dosage was observed for copper

(Cu), thalium (Tl), bismuth (Bi), lead (Pb), cesium (Cs), gold

(Au), zinc (Zn), mercury (Hg), selenium (Se), and chromium

(Cr). The slowest excretion rate was measured for arsenic

(As), cadmium (Cd), iron (Fe), methylmecury (MeHg), and tin

(Sn). No substantial elimination rate decline was observed for

MeHg and Fe, and the decline was small for Tl, Cs, Hg, Sn, Co,

Ag, Zn, Cr, and As. Elimination of Ag and Mn via feces was

fast, with more than 70% eliminated on the first day. Cu, Tl,

Pb, and Zn were excreted at a slower rate, with 30.6 to 38.3%

excreted on the first day. The rest of the metals were

eliminated slowly by the intestinal route. Co was removed
rapidly via urine, while Pb, Sn, Zn, MeHg, Ag, Fe, Mn, and Cd

were eliminated slowly. The biliary excretion of Ag, As, and

Mn was fast, with 25.5, 30.2 and 16.2% eliminated in two

hours. Cu, Se, Cd, Pb, Bi, and Co were eliminated at an

intermediate rate via the biliary route. Ag, As, Mn, Cu, Se,

Cd, Pb, Bi, and MeHg were highly concentrated in bile relative

to plasma. Liver and kidney contained the highest

concentrations of most metals. The intestinal route was the

major path of elimination for Ag, Mn, Cu, Tl, Pb, Zn, Cd, Fe,

and MeHg. Co, Cs, Au, Se, and Cr, were removed predominantly

by urine. For Bi, Hg, As, and Sn the two routes were similar.

[Gregus Z, Klaassen CO; Toxicol Appl Pharm 85 (1): 24-38

(1986)].

Baseline data on Cd accumulation in organs and tissues, and

their variations with age, sex, and habitat in Japanese serows

(Capricornus crispus) were determined. The animals were killed

during the winter 1981-82 in the Gifu and Nagano Prefectures,

Japan. The Cd concentrations were measured by flame absorption

spectrometry. On a wet basis, the mean Cd concentration in

muscle, liver, kidneys, and the whole body of fetuses

(gestation age 0.3-0.7 yr, N= 13) was <1.0 ng/g; in fawns (age

0.0-0.5 yr, N= 12) was 18, 29, 60, and 22 ng/g, respectively;

in yearlings (age 0.5-2.5 yr, N= 6)was 9, 51, 60, and 31 ng/g,

respectively; in adults (age 2.5 to 10 yr, N= 42) was 16, 130,

950, and 42 ng/g, respectively; and in adults (age 10 to 17.5

yr, N= 17) was 20, 131, 1080, and 52 ng/g, respectively. The

mean Cd concentration in fleece of fawns, yearlings, and

adults (age 2.5 to 10 yr) was 55, 37, and 28 ng/g,

respectively. The Cd levels in bone samples form two adult

serows ranged from 0.4 to 0.8 ug/g. The body burdens of

fetuses were low (<1%) compared with those of their mothers.

The placental transfer of Cd was negligible; after birth, Cd

levels increased each year. There was a significant difference

in Cd concentration between collection locations, which was

attributed to direct intake of Cd in soil. [Honda K et al;

Arch Environ Contam Toxicol 16: 551-61 (1987)].

The relationship between tissue levels of metallothionein and

metal concentrations was assessed for zinc, copper, and

cadmium in ten different organs from human autopsies and rats.

Human autopsy specimens were obtained from ten males between

the ages of 20 and 50 years within 2 days of sudden death.

Tissues assayed included pancreas, liver, kidney, brain, small

intestine, stomach, muscle, heart, lung, and spleen. Human

metallothionein levels were higher than rat levels for all

tissues assayed except brain and small intestine. The highest

metallothionein levels were found in human liver and kidney

cortex and rat kidney and brain. Zinc levels were highest for

human liver, kidney, and muscle; and copper levels were

highest for human liver, brain, and heart and rat liver,

kidney, and heart. Elevated cadmium levels were found in human

liver and kidney. All cadmium levels were below detectable

limits in rats. Significant correlations were established
between metallothionein levels and zinc and copper in human

liver and between metallothionein and cadmium in human kidney

cortex. [Heilmauer HE et al; Toxicol Lett 38 (3): 205-11

(1987)].

Laboratory and/or Field Analyses:

While a number of different techniques (including

polarography, ion chromatography, and mass spectroscopy) are

available to measure concentrations of cadmium in solutions such as

natural waters and the acid digests of solid materials [861,907],

the most common methods use atomic absorption spectrometry (AAS)

and inductively-coupled plasma emission spectrometry (ICP) [907].

Low concentration criteria or benchmarks may require

relatively rigorous methods such as graphite furnace AAS rather

than ICP methods, and detection limits should be no higher than

comparison benchmarks or criteria for various media (water,

sediments, soil, tissues, etc), some of which are low (see sections

above). For critical risk assessment applications, the water

detection limit may need to be very low since sensitive species

benchmarks are as low as 0.013 ug/L (ppb) [649]. EPA method 1640

(see details below) allows a water MDL detection limit of 0.0024

ug/L [1001]. EPA method 1637 allows a water MDL detection limit of

0.0075 ug/L [1003] to 0.0074 ug/L [1001]. Lowest EPA water quality

criterion is 0.32 ug/L [1001,1003].

For other routine monitoring when benchmark or criteria

comparisons do not require lower levels, the ICP detection limits

should usually not exceed the following default concentrations

often recommended by the Fish and Wildlife Service and the National

Park Service (Roy Irwin, National Park Service, Personal

Communication, 1996):

0.10 ppm dry weight in tissues, 

0.20 ppm in sediments and soils, and 

0.0005 ppm in water. 

Note: Routine Atomic absorption (AA) detection limits for

water can be as low as 0.0001 mg/L (40 CFR Part 141.23,

part of the Drinking Water Regulations).

Older detection limits for instruments measuring cadmium in

solution were 1 ug/L for flame AAS, 0.001 ug/L for graphite furnace

AAS, 800 ug/L for flame emission spectrometry, 2 ug/L for ICP, and

0.2 ug.L for ICP-mass spectrometry [907].

Acceptable containers (after proper cleaning per EPA

protocols) for Antimony, Arsenic, Cadmium, Copper, Lead, Nickel,

Selenium, Silver, Thallium, and Zinc: 500-mL or 1-L fluoropolymer,

conventional or linear polyethylene, polycarbonate, or

polypropylene containers with lid [1003].

Notes on total vs. acid soluble vs. dissolved metals: 

Although most of the lab tests done to develop water

quality criteria and other benchmarks were originally
based on "total" values rather than "dissolved" values,

the lab settings were typically fairly clean and the

numbers generated by the lab tests are therefore often

even more comparable to field "dissolved" values than to

field "total" values (Glen Suter, Oak Ridge National Lab,

Personal Communication, 1995). As of January 1995, the

U.S. EPA was recommending that states use dissolved

measurements in water quality standards for metals, in

concert with recommendations EPA previously made for the

Great Lakes [672]. The conversion factors recommended by

EPA for converting total recoverable metals criteria to

dissolved metal criteria were given as follows [672]:

Cadmium conversion for acute or chronic criteria:

0.850 (that is, total recoverable metals criteria x

0.850 = dissolved metals criteria).

The conversion factors recommended by EPA for converting

total recoverable cadmium to dissolved concentrations in

the January 1997 draft EPA Guidelines for 5 year 305(B)

assessments were:

Cadmium conversion at a hardness of 50 mg/L: 0.973

for the Criterion Maximum Concentration (CMC). 

Cadmium conversion at a hardness of 50 mg/L: 0.938

for the Criterion Continuous Concentration (CCC). 

Cadmium conversion at a hardness of 100 mg/L: 0.944

for the Criterion Maximum Concentration (CMC). 

Cadmium conversion at a hardness of 100 mg/L: 0.909

for the Criterion Continuous Concentration (CCC). 

Cadmium conversion at a hardness of 200 mg/L: 0.915

for the Criterion Maximum Concentration (CMC). 

Cadmium conversion at a hardness of 200 mg/L: 0.880

for the Criterion Continuous Concentration (CCC). 

Note: None of these "generic" conversion

factors work well for all areas. Both total

and dissolved concentrations should be checked

at new locations before relying on generic

conversion factors (Pat Davies, Colorado

Division of Wildlife, personal communication,

1997).

Filtration and Acidification of Water Samples:

For ICP water samples for metals, EPA recommends the

following (40 CFR Part 136, Appendix C, pertaining to ICP

analyses using method 200.7, 1994 edition of CFR Part

40):
1) For samples of "total or total recoverable

elements," samples should be acidified to a pH of

two or less at the time of collection or as soon as

possible thereafter.

Note: In more recent (1996) guidance related

to the more rigorous method 1669, EPA

clarified (some would say confused or added

data variability) the issue of when to acidify

by stating:

"Preservation recommendations for

Antimony, Arsenic, Cadmium, Copper, Lead,

Nickel, Selenium, Silver, Thallium, and

Zinc: Add 5 mL of 10% HN03 to 1-L sample;

preserve on-site or immediately upon

laboratory receipt" [1003]. 

Note: the nitric acid (triple

distilled or not?) and dilution

water (contaminated or not?) and

containers (proper type, cleaned

correctly or not?) used are all

potential sources of contamination

(see more detailed note below

related to data variation factors).

2) For determination of dissolved elements, the

samples must be filtered through a 0.45 micron

membrane filter as soon as soon as practical after

collection, using the first 50-100 ml to rinse the

filter flask. Acidify the filtrate with nitric

acid to a pH of 2 or less. Normally 3 mL of (1+1)

of nitric acid per liter should be sufficient to

preserve the sample.

3) For determination of suspended elements, the

samples must be filtered through a 0.45 micron

membrane filter as soon as soon as practical after

collection. The filter is then transferred to a

suitable container for storage and shipment, with

no preservation required.

Sources of potential variation in contaminants data:

Variation in concentrations of contaminants may

sometimes be due to differences in how individual

investigators treat samples in the field and lab

rather than true differences in environmental

concentrations. See also notes in disclaimer

section at the top of this file. It was

recognition that collectors and labs often

contaminate samples that led EPA to develop the

1600 series of water protocols for low detection
limit applications [1001,1002,1003,1004]. In

comparing contaminants data from different labs,

different states, and different agencies, one

should keep in mind that they are often not very

comparable. They may be as different as apples and

oranges since:

1) Different Agencies (EPA, USGS, NOAA, and

various State Agencies) publish different lab

and field protocols. Each of these protocols

is different and has typically changed over

time.

Note: Even "Standard EPA Methods" which

are supposedly widely used by

consultants, industry, and academia, have

been variable over time and between

application category (Drinking Water vs.

NPDES, vs. RCRA, vs. CERCLA, vs. WaterQuality Based permits, etc.). 

Preservation and other details of various

EPA lab and field protocols have changed

over the years, just as they have at USGS

and various States and other agencies.

USGS data from 30 years ago may be

different than USGS data today due to

differences (drift) in lab and field

protocols rather than differences in

environmental concentrations.

2) Independent labs and field investigators

are not always using "the latest and greatest

methods," and it is difficult for them to

keep up with all the changes from various

agencies in the midst of their "real world"

busy lives. Updates are not always convenient

to obtain. For example, EPA changes are

scattered through various proposed Federal

Register Notices, various updates of CFRs, and

numerous publications originating in many

different parts of EPA and their contractors.

The wording is sometimes imprecise and is

often inconsistent between EPA methods for

different applications. 

3) The details of the way one person collects,

filters, and acidifies water samples in the

field may be different than the way another

does it. Sources of potential variation

include the following:

A) The protocol phrases "As soon as

practical or as soon as possible."
Different situations can change the

elapsed time considered by the field

collector to be "as soon as practical."

It may take different amounts of time to

get to a safe or otherwise optimum place

to filter and/or acidify and cool the

samples. In one case precipitation and

other changes could be going on in the

collection bottle while the bottle is on

the way to filtration and acidification.

In other cases, the field collector

filters and acidifies the samples within

minutes. Weather, safety concerns, and

many other factors could play a role.

B) Differences in numerous other details

of the method used can drastically change

the results. Some cold, wet, hurried, or

fire ant-bitten collectors might decide

that it is not "practical" to filter and

acidify quite so immediately in the

field, and may decide the shore, a

vehicle, a motel room, or even a remote

lab are more "practical" locations.

Filtering and acidifying in the field

immediately has been thought of as a

better option for consistency (see copper

and silver entries for examples of what

can happen if there is a delay).

However, in recent methodology designed

to prevent some the contamination and

variability listed above, EPA has

recently suggested that waiting until the

sample arrives at the lab before

acidifying is OK [1003]. 

C) What kind of .45 micron filter was

used? The flat plate filters that were

used for years tended to filter .45

micron sizes at first and then smaller

and smaller sizes as the filtering

proceeded and the filter loaded up with

particulate matter. As the filter

clogged, the openings grew smaller and

colloids and smaller diameter matter

began to be trapped on the filter. For

this reason, both the USGS and EPA 1600

series protocols have gone to tortuouspath capsule filters that tend to filter

.45 micron sizes more reliably over time.

Example of specifications from EPA method

1669:

Filter—0.45-um, 15-mm diameter or
larger, tortuous-path capsule

filters, Gelman Supor 12175, or

equivalent [1003].

D) "Normally 3 mL of (1+1) of nitric acid

per liter should be sufficient to

preserve the (water) sample" (40 CFR Part

136, Appendix C, pertaining to ICP

analyses using method 200.7, 1994 edition

of CFR Part 40). Sometimes it is not,

depending on alkalinity and other

factors. What field collectors sometimes

(often?) do is just use pop tabs of 3 mL

of nitric acid and hope for the best

rather than checking to see that the

acidity has been lowered to below a pH of

two. EPA CFR guidelines just call for a

pH of below two, whereas samples meant to

be "acid soluble" metals call for a pH of

1.5 to 2.0 [25]. See also, various USEPA

1984 to 1985 Ambient Water Quality

Criteria Documents for individual metals.

Note: Some shippers will not accept

samples with a pH of less than 1 for

standard shipping (John Benham,

National Parks Service Personal

Communication, 1997).

E) One person might use triple distilled

concentrated nitric acid rather than

reagent grades of acid to avoid possible

contamination in the acid, while another

may not. When using very low detection

limits, some types of acid may introduce

contamination and influence the results.

Using a 10% dilution of nitric acid as

called for by EPA [1003] is another

potential source of contamination, since

the dilution water and/or containers may

be contaminated. Sometimes people may be

incorrectly determining that background

concentrations are high due to

contamination sources such as these (Pat

Davies, Colorado Division of Wildlife,

personal communication, 1997).

Note: Just using triple distilled

nitric acid may not be the total

answer to potential contamination.

The key issue to be sure that the

acid used is free of the metals

being analyzed. In guidance for EPA

method 1669, the use of "ultrapure
nitric acid; or Nitric acid, dilute,

trace-metal grade" is specified

[1003]. In guidance for EPA method

1638, the use of "Nitric

acid—concentrated (sp gr 1.41),

Seastar or equivalent" is specified

[1003].

F) Holding times can strongly influence

the results and there can be quite a bit

of variation even within EPA recommended

6 month limits (see Silver entry for

details). Holding times recommended for

EPA for water samples of metals other

than mercury or chromium VI have usually

been listed as 6 months (Federal

Register, Volume 49, No. 209, Friday,

October 28, 1984, page 43260). In the

1994 version of the CFR, NPDES holding

times for mercury and Chromium VI are the

same ones listed in 1984, but no EPA

holding times are given for other metals

(40 CFR, Part 136.3, Table 2, page 397,

1994). EPA sources stated this was a

typo, that no one else brought it to

their attention in the last 3 years, that

6 months is still an operable holding

time for "other metals" including this

one, and that 6 months is actually an

artifact from the days when 6 month

composite samples were used for NPDES

permits rather than having been

originally scientifically derived. 

Counterpoint: Although some

information suggests that 6 months

is probably too long for some

contaminants in some scenarios (see

silver and copper entries), not all

of the information in the literature

casts the 6 month metals holding

time in such questionable light. In

one study, two EPA research chemists

found that preservation under

certain conditions of drinking water

(EPA Method 200.8) metals samples to

a pH of less than 2 effectively

stabilized the metal concentrations

for 6 months. They found that trace

metal standards in the 10 to 50 ug/L

concentration could be held in 1%

nitric acid if a 5% change of

concentration was acceptable [1009].

Some metal concentrations changed
more than 5% (Zinc up to 24%,

Selenium up to 23%) [1009].

Vanadium, Manganese and Arsenic

changed up to 5-7% [1009]. In some

of the trials, metals were higher

after 6 months due to leaching from

containers, while in some they were

lower [1009]. The changes were

nevertheless considered not of great

consequence related to drinking

water MCLs and EPA method 200.8

[1009]. However, it is not clear

that the careful measures utilized

(like rechecking to make sure the pH

was less than 2, the use of

particular kinds of water samples,

the use of particular acids, etc.)

in this one study replicates what

goes on in day to day ("real world")

contaminants lab work around the

country.

Some EPA sources state that 6 months

should be OK if the sample bottle is

vigorously shaken and re-acidified

in the lab prior to lab analyses, a

practice not universally or even

particularly commonly done in labs

today. The degree to which a water

sample is re-acidified, re-checked

for pH, shaken before analysis, and

the length of time it sits before

and after these steps, seems to vary

a lot between laboratories, and EPA

guidance for various methods is not

consistent. Some labs recheck pH,

some don't. Some shake, some don't,

etc. For drinking water,

preservation is considered complete

after the sample is held in pH of

less than 2 for at least 16 hours

[1007]. New EPA Method 1638

specifies: 

"Store the preserved sample for

a minimum of 48 h at 0–4(C to

allow the acid to completely

dissolve the metal(s) adsorbed

on the container walls. The

sample pH should be verified as

<2 immediately before

withdrawing an aliquot for

processing or direct analysis.

If, for some reason such as
high alkalinity, the sample pH

is verified to be >2, more acid

must be added and the sample

held for sixteen hours until

verified to be pH <2" [1003].

For many other methods, the minimum

holding time in acid is not stated

or is different (see various EPA and

other Agency methods). 

G) If present, air in head space can

cause changes in water sample

concentrations (Roy Irwin, National Park

Service, Personal Communication, based on

several discussions with EPA employees

and various lab managers in February

1997).

Note: air from the atmosphere or in

headspace can cause oxidation of

anaerobic groundwater or anaerobic

sediment samples. This oxidation

can cause changes in chemical

oxidation states of contaminants in

the sample, so that the results are

not typical of the anaerobic

conditions which were present in the

environment prior to sampling (John

Benham, National Park Service,

Personal Communication, 1997). 

H) When is the sample shaken in the lab

or the field? If the filter is acidified

in the field, it will be shaken on the

way back to the lab. If lab acidified,

how much and when is the sample shaken

and then allowed to sit again for various

times periods before analyses? Many

methods treat this differently, and what

many field collectors and labs actually

do before analyzing samples is different

as well. For EPA method 1638, the word

shake appears in the "Alternate total

recoverable digestion procedure": 

"..Tightly recap the container and

shake thoroughly" [1003].

I) If one field filters and acidifies,

one often changes metal concentrations

and colloidal content compared to samples

not treated in this manner. Acidifying

effects microbial changes. If one holds
the samples a while before filtering and

acidifying, the situation changes. In

collection bottles, there are potential

aging effects: temperature changes,

changes in basic water chemistry as

oxygen and other dissolved gasses move

from the water into the headspace of air

at the top, potential aggregation of

colloidal materials, precipitation of

greater sizes over time, development of

bigger and more colloids, and more

sorption (Roy Irwin, National Park

Service, personal communication, 1997). 

4) The guidance of exactly where to take

water samples varies between various state and

federal protocols. Taking water samples at

the surface microlayer tends to increase

concentrations of various contaminants

including metals. Other areas of the water

column tend to produce different

concentrations. Large quantities of

anthropogenic substances frequently occur in

the surface microlayer at concentrations

ranging from 100 to 10,000 times greater than

those in the water column [593]. These

anthropogenic substances can include plastics,

tar lumps, PAHs, chlorinated hydrocarbons, as

well as lead, copper, zinc, and nickel [593].

Sometimes a perceived trend can be more the

result of the details of the sample microlocation rather than real changes in

environmental concentrations (Roy Irwin,

National Park Service, personal communication,

1997). The new EPA method 1669 mentions the

microlayer, and states that one can use a

fluoropolymer closing mechanism, threaded onto

the bottle, to open and close a certain type

of bottle under water, thereby avoiding

surface microlayer contamination [1003].

However, even this relatively new EPA method

1669 also gives recommendations for ways to

sample directly at the surface, and does not

discourage the use of surface samples.

5) Although the above examples are mostly

related to water samples, variability in field

and lab methods can also greatly impact

contaminant concentrations in tissues, soil,

and sediments. Sediment samples from

different microhabitats in a river (backwater

eddy pools vs. attached bars, vs. detached

bars, vs. high gradient riffles vs. low

gradient riffles, vs. glides, etc.) tend to
have drastically different concentrations of

metals as well as very different data

variances (Andrew Marcus, Montana State

University, personal communication, 1995).

Thus, data is only optimally comparable if

both data collectors were studying the same

mix of microhabitats, a stratified sampling

approach which would be unusual when comparing

random data from different investigators. 

6) Just as there are numerous ways to

contaminate, store, ship, and handle water

samples, so are there different agency

protocols and many different ways to handle

samples from other media. One investigator

may use dry ice in the field, another may bury

the samples in a large amount of regular ice

immediately after collection in the field,

while a third might place samples on top of a

small amount of ice in a large ice chest. The

speed with which samples are chilled can

result in different results not only for

concentrations of organics, but also for the

different chemical species (forms) of metals

(Roy Irwin, National Park Service, personal

communication, 1997). 

7) In comparing contaminants metals data, soil

and sediment contaminant concentrations should

usually be (but seldom has been) normalized

for grain size, total organic carbon, and/or

acid volatile sulfides before biologicallymeaningful or trend-meaningful comparisons are

possible (Roy Irwin, National Park Service,

Personal Communication, 1997).

8) There has been tremendous variability in

the precautions various investigators have

utilized to avoid sample contamination.

Contamination from collecting gear, clothes,

collecting vehicles, skin, hair, collector's

breath, improper or inadequately cleaned

sample containers, and countless other sources

must carefully be avoided when using methods

with very low detection limits [1003]. 

 

As of 1997, the problem of lack of data comparability (not

only for water methods but also for soil, sediment, and tissue

methods) between different "standard methods" recommended by

different agencies seemed to be getting worse, if anything, rather

than better. The trend in quality assurance seemed to be for

various agencies, including the EPA and others, to insist on

quality assurance plans for each project. In addition to quality

control steps (blanks, duplicates, spikes, etc.), these quality
assurance plans call for a step of insuring data comparability

[1015,1017]. However, the data comparability step is often not

given sufficient consideration. The tendency of agency guidance

(such as EPA SW-846 methods and some other new EPA methods for bioconcentratable substances) to allow more and more flexibility to

select options at various points along the way, makes it harder in

insure data comparability or method validity. Even volunteer

monitoring programs are now strongly encouraged to develop and use

quality assurance project plans [1015,1017]. 

At minimum, before using contaminants data from diverse

sources, one should determine that field collection methods,

detection limits, and lab quality control techniques were

acceptable and comparable. The goal is that the analysis in the

concentration range of the comparison benchmark concentration

should be very precise and accurate. 

It should be kept in mind that quality control field and lab

blanks and duplicates will not help in the data quality assurance

goal as well as intended if one is using a method prone to false

negatives. Methods may be prone to quality assurance problems due

to the use of detection limits that are too high, the loss or

addition of contaminants through inappropriate handling, or the use

of inappropriate methods.

Highlights from EPA Lab Method 1640: Determination of trace

elements in ambient waters by on-line chelation

preconcentration and inductively coupled plasma-mass

spectrometry:

This method is for the determination of dissolved

elements in ambient waters at EPA water quality criteria

(WQC) levels using on-line chelation preconcentration and

inductively coupled plasma-mass spectrometry (ICP-MS)

[1003]. It may also be used for determination of total

recoverable element concentrations in these waters

[1003]. This method was developed by integrating the

analytical procedures contained in EPA Method 200.10 with

the quality control (QC) and sample handling procedures

necessary to avoid contamination and ensure the validity

of analytical results during sampling and analysis for

metals at EPA WQC levels [1003]. This method contains QC

procedures that will assure that contamination will be

detected when blanks accompanying samples are analyzed

[1003]. This method is accompanied by Method 1669:

Sampling Ambient Water for Determination of Trace Metals

at EPA Water Quality Criteria Levels (the "Sampling

Method") [1003]. The Sampling Method is necessary to

ensure that contamination will not compromise trace

metals determinations during the sampling process [1003].

This method is applicable to the following elements:

Cadmium (Cd), Copper (Cu), Lead (Pb), and Nickel

(Ni) [1003].
Many of the requirements for this method are similar to

those for other EPA 1600 series methods [1003].

As of March 1997, the EPA 1600 series methods had not yet

been officially approved in 40 CFR for use in NPDES

permits, but the improvements in these methods were

suggested by EPA staff to be wise practice when

attempting low detection limit analyses for metals

[1003].

For dissolved metal determinations, samples must be

filtered through a 0.45-um capsule filter at the field

site [1003]. The Sampling Method describes the filtering

procedures [1003]. The filtered samples may be preserved

in the field or transported to the laboratory for

preservation [1003]. Procedures for field preservation

are detailed in the Sampling Method; provides procedures

for laboratory preservation are provided in this method

[1003].

Acid solubilization is required before the determination

of total recoverable elements to aid breakdown of

complexes or colloids that might influence trace element

recoveries [1003].

This method should be used by analysts experienced in the

use of inductively coupled plasma mass spectrometry (ICPMS), including the interpretation of spectral and matrix

interferences and procedures for their correction; and

should be used only by personnel thoroughly trained in

the handling and analysis of samples for determination of

metals at EPA WQC levels [1003]. A minimum of six

months' experience with commercial instrumentation is

recommended [1003].

Sample preservation—Preservation of samples and field

blanks for both dissolved and total recoverable elements

may be performed in the field when the samples are

collected or in the laboratory [1003]. However, to avoid

the hazards of strong acids in the field and transport

restrictions, to minimize the potential for sample

contamination, and to expedite field operations, the

sampling team may prefer to ship the samples to the

laboratory within 2 weeks of collection [1003]. Samples

and field blanks should be preserved at the laboratory

immediately when they are received [1003]. For all

metals, preservation involves the addition of 10% HNO3 to

bring the sample to pH <2 [1003]. For samples received

at neutral pH, approx 5 mL of 10% HNO3 per liter will be

required [1003].

Store the preserved sample for a minimum of 48 h at 0–4(C

to allow the acid to completely dissolve the metal(s)

adsorbed on the container walls [1003]. The sample pH
should be verified as <2 immediately before an aliquot is

withdrawn for processing or direct analysis [1003]. If,

for some reason such as high alkalinity, the sample pH is

verified to be >2, more acid must be added and the sample

held for 16 h until verified to be pH <2 [1003].

Highlights from EPA Method 1669 for Sampling Ambient Water for

Trace Metals at EPA Water Quality Criteria Levels [1003]:

As of March 1997, the 1600 series methods had not yet

been officially approved in 40 CFR for use in NPDES

permits, but the improvements in these methods were

suggested by EPA staff to be wise practice when

attempting low detection limit analyses for metals.

This "field method details" protocol is for the

collection and filtration of ambient water samples for

subsequent determination of total and dissolved Antimony,

Arsenic, Cadmium, Copper, Chromium III, Chromium VI,

Lead, Mercury, Nickel, Selenium, Silver, Thallium, and

Zinc, at low (Water Quality Criteria Range)

concentrations [1003]. It is designed to support the

implementation of water quality monitoring and permitting

programs administered under the Clean Water Act [1003].

This method is not intended for determination of metals

at concentrations normally found in treated and untreated

discharges from industrial facilities [1003]. Existing

regulations (40 CFR Parts 400–500) typically limit

concentrations in industrial discharges to the mid to

high part-per-billion (ppb) range, whereas ambient metals

concentrations are normally in the low part-per-trillion

(ppt) to low ppb range [1003]. This guidance is

therefore directed at the collection of samples to be

measured at or near the water quality criteria levels

[1003]. Often these methods will be necessary in a water

quality criteria-based approach to EPA permitting [1001].

Actual concentration ranges to which this guidance is

applicable will be dependent on the sample matrix,

dilution levels, and other laboratory operating

conditions [1003].

The ease of contaminating ambient water samples with the

metal(s) of interest and interfering substances cannot be

overemphasized [1003]. This method includes sampling

techniques that should maximize the ability of the

sampling team to collect samples reliably and eliminate

sample contamination [1003].

Clean and ultraclean—The terms "clean" and "ultraclean"

have been used in other Agency guidance [1004] to

describe the techniques needed to reduce or eliminate

contamination in trace metals determinations [1003].

These terms are not used in this sampling method due to
a lack of exact definitions [1003]. However, the

information provided in this method is consistent with

summary guidance on clean and ultraclean techniques

[1004].

Preventing ambient water samples from becoming

contaminated during the sampling and analytical process

is the greatest challenge faced in trace metals

determinations [1003]. In recent years, it has been

shown that much of the historical trace metals data

collected in ambient water are erroneously high because

the concentrations reflect contamination from sampling

and analysis rather than ambient levels [1003].

Therefore, it is imperative that extreme care be taken to

avoid contamination when collecting and analyzing ambient

water samples for trace metals [1003].

There are numerous routes by which samples may become

contaminated [1003]. Potential sources of trace metals

contamination during sampling include metallic or metalcontaining sampling equipment, containers, labware (e.g.

talc gloves that contain high levels of zinc), reagents,

and deionized water; improperly cleaned and stored

equipment, labware, and reagents; and atmospheric inputs

such as dirt and dust from automobile exhaust, cigarette

smoke, nearby roads, bridges, wires, and poles [1003].

Even human contact can be a source of trace metals

contamination [1003]. For example, it has been

demonstrated that dental work (e.g., mercury amalgam

fillings) in the mouths of laboratory personnel can

contaminate samples that are directly exposed to

exhalation [1003].

For dissolved metal determinations, samples must be

filtered through a 0.45-um capsule filter at the field

site [1003]. The filtering procedures are described in

this method [1003]. The filtered samples may be

preserved in the field or transported to the laboratory

for preservation [1003]. 

This document is intended as guidance only [1003].

Use of the terms "must," "may," and "should" are

included to mean that EPA believes that these

procedures must, may, or should be followed in

order to produce the desired results when using

this guidance [1003]. In addition, the guidance is

intended to be performance-based, in that the use

of less stringent procedures may be used so long as

neither samples nor blanks are contaminated when

following those modified procedures [1003].

Because the only way to measure the performance of

the modified procedures is through the collection

and analysis of uncontaminated blank samples in

accordance with this guidance and the referenced
methods, it is highly recommended that any

modifications be thoroughly evaluated and

demonstrated to be effective before field

samples are collected [1003].

The method includes a great many details regarding

prevention of field contamination of samples, including

clothing needed, clean hands vs. dirty hands operations,

and numerous other details [1003]. 

Surface sampling devices—Surface samples are collected

using a grab sampling technique [1003]. Samples may be

collected manually by direct submersion of the bottle

into the water or by using a grab sampling device [1003].

Grab samplers may be used at sites where depth profiling

is neither practical nor necessary [1003].

An alternate grab sampler design is available [1003].

This grab sampler is used for discrete water samples and

is constructed so that a capped clean bottle can be

submerged, the cap removed, sample collected, and bottle

recapped at a selected depth [1003]. This device

eliminates sample contact with conventional samplers

(e.g., Niskin bottles), thereby reducing the risk of

extraneous contamination [1003]. Because a fresh bottle

is used for each sample, carryover from previous samples

is eliminated [1003].

Subsurface sampling devices—Subsurface sample collection

may be appropriate in lakes and sluggish deep river

environments or where depth profiling is determined to be

necessary [1003]. Subsurface samples are collected by

pumping the sample into a sample bottle [1003]. Examples

of subsurface collection systems include the jar system

device or the continuous-flow apparatus [1003]. 

Advantages of the jar sampler for depth sampling are (1)

all wetted surfaces are fluoropolymer and can be

rigorously cleaned; (2) the sample is collected into a

sample jar from which the sample is readily recovered,

and the jar can be easily recleaned; (3) the suction

device (a peristaltic or rotary vacuum pump, is located

in the boat, isolated from the sampling jar; (4) the

sampling jar can be continuously flushed with sample, at

sampling depth, to equilibrate the system; and (5) the

sample does not travel through long lengths of tubing

that are more difficult to clean and keep clean [1003].

In addition, the device is designed to eliminate

atmospheric contact with the sample during collection

[1003].

Selection of a representative site for surface water

sampling is based on many factors including: study

objectives, water use, point source discharges, non-point
source discharges, tributaries, changes in stream

characteristics, types of stream bed, stream depth,

turbulence, and the presence of structures (bridges,

dams, etc.) [1003]. When collecting samples to determine

ambient levels of trace metals, the presence of potential

sources of metal contamination are of extreme importance

in site selection [1003].

Ideally, the selected sampling site will exhibit a high

degree of cross-sectional homogeneity [1003]. It may be

possible to use previously collected data to identify

locations for samples that are well mixed or are

vertically or horizontally stratified [1003]. Since

mixing is principally governed by turbulence and water

velocity, the selection of a site immediately downstream

of a riffle area will ensure good vertical mixing [1003].

Horizontal mixing occurs in constrictions in the channel

[1003]. In the absence of turbulent areas, the selection

of a site that is clear of immediate point sources, such

as industrial effluents, is preferred for the collection

of ambient water samples) [1003].

To minimize contamination from trace metals in the

atmosphere, ambient water samples should be collected

from sites that are as far as possible (e.g., at least

several hundred feet) from any metal supports, bridges,

wires or poles [1003]. Similarly, samples should be

collected as far as possible from regularly or heavily

traveled roads [1003]. If it is not possible to avoid

collection near roadways, it is advisable to study

traffic patterns and plan sampling events during lowest

traffic flow [1003].

The sampling activity should be planned to collect

samples known or suspected to contain the lowest

concentrations of trace metals first, finishing with the

samples known or suspected to contain the highest

concentrations [1003]. For example, if samples are

collected from a flowing river or stream near an

industrial or municipal discharge, the upstream sample

should be collected first, the downstream sample

collected second, and the sample nearest the discharge

collected last [1003]. If the concentrations of

pollutants is not known and cannot be estimated, it is

necessary to use precleaned sampling equipment at each

sampling location [1003].

One grab sampler consists of a heavy fluoropolymer collar

fastened to the end of a 2-m-long polyethylene pole,

which serves to remove the sampling personnel from the

immediate vicinity of the sampling point [1003]. The

collar holds the sample bottle [1003]. A fluoropolymer

closing mechanism, threaded onto the bottle, enables the

sampler to open and close the bottle under water, thereby
avoiding surface microlayer contamination [1003].

Polyethylene, polycarbonate, and polypropylene are also

acceptable construction materials unless mercury is a

target analyte [1003]. Assembly of the cleaned sampling

device is as follows:

Sample collection procedure—Before collecting ambient

water samples, consideration should be given to the type

of sample to be collected, the amount of sample needed,

and the devices to be used (grab, surface, or subsurface

samplers) [1003]. Sufficient sample volume should be

collected to allow for necessary quality control

analyses, such as matrix spike/ matrix spike duplicate

analyses [1003].

Highlights from EPA Method 1637: Determination of Trace

Elements in Ambient Waters by Off-Line Chelation

Preconcentration and Stabilized Temperature Graphite Furnace

Atomic Absorption [1003]: 

This method, proposed by EPA in 1996, provides procedures

for the determination of dissolved elements in ambient

waters at EPA water quality criteria (WQC) levels using

off-line chelation preconcentration and stabilized

temperature graphite furnace atomic absorption (GFAA)

[1003]. It may also be used for determination of total

recoverable element concentrations in these waters

[1003]. This method was developed by integrating the

analytical procedures in EPA Method 200.13 with the

stringent quality control (QC) and sample handling

procedures necessary to avoid contamination and ensure

the validity of analytical results during sampling and

analysis for metals at EPA WQC levels [1003]. This

method contains QC procedures that will ensure that

contamination will be detected when blanks accompanying

samples are analyzed [1003]. This method is accompanied

by Method 1669: Sampling Ambient Water for Determination

of Trace Metals at EPA Water Quality Criteria Levels (the

"Sampling Method") [1003]. The Sampling Method is

necessary to ensure that contamination will not

compromise trace metals determinations during the

sampling process [1003].

EPA method 1637 allows a water MDL detection limit of

0.0075 ug/L [1003]. EPA method 1640 allows a water MDL

detection limit of 0.0024 [1003]. Lowest EPA water

quality criterion is 0.32 ug/L [1003].

As of March 1997, the EPA 1600 series methods had not yet

been officially approved in 40 CFR for use in NPDES

permits, but the improvements in these methods were

suggested by EPA staff to be wise practice when

attempting low detection limit analyses for metals.
Highlights from EPA Method 1638: Determination of Trace

Elements in Ambient Waters by Inductively Coupled Plasma —

Mass Spectrometry:

This 1996 proposed EPA method is for the determination of

dissolved elements in ambient waters at EPA water quality

criteria (WQC) levels using inductively coupled plasmamass spectrometry (ICP-MS) [1003]. It may also be used

for determination of total recoverable element

concentrations in these waters [1003]. This method was

developed by integrating the analytical procedures in EPA

Method 200.8 with the quality control (QC) and sample

handling procedures necessary to avoid contamination and

ensure the validity of analytical results during sampling

and analysis for metals at EPA WQC levels [1003]. This

method contains QC procedures that will assure that

contamination will be detected when blanks accompanying

samples are analyzed [1003]. This method is accompanied

by Method 1669: Sampling Ambient Water for Determination

of Trace Metals at EPA Water Quality Criteria Levels

("Sampling Method") [1003]. The Sampling Method is

necessary to assure that trace metals determinations will

not be compromised by contamination during the sampling

process [1003].

This method may be used with the following metals:

Antimony (Sb), CAS 7440-36-0

Cadmium (Cd), CAS 7440-43-9

Copper (Cu), CAS 7440-50-8

Lead (Pb), CAS 7439-92-1

Nickel (Ni), CAS 7440-02-0

Selenium (Se), CAS 7782-49-2

Silver (Ag), CAS 7440-22-4

Thallium (Tl), CAS 7440-28-0

Zinc (Zn), CAS 7440-66-6

As of March 1997, the EPA 1600 series methods had not yet

been officially approved in 40 CFR for use in NPDES

permits, but the improvements in these methods were

suggested by EPA staff to be wise practice when

attempting low detection limit analyses for metals

[1003].

This method is not intended for determination of metals

at concentrations normally found in treated and untreated

discharges from industrial facilities [1003]. Existing

regulations (40 CFR Parts 400–500) typically limit

concentrations in industrial discharges to the mid to

high part-per-billion (ppb) range, whereas ambient metals

concentrations are normally in the low part-per-trillion

(ppt) to low ppb range [1003].

The ease of contaminating ambient water samples with the
metal(s) of interest and interfering substances cannot be

overemphasized [1003]. This method includes suggestions

for improvements in facilities and analytical techniques

that should maximize the ability of the laboratory to

make reliable trace metals determinations and minimize

contamination [1003]. These suggestions are ...based on

findings of researchers performing trace metals analyses

[1003]. Additional suggestions for improvement of

existing facilities may be found in EPA's Guidance for

Establishing Trace Metals Clean Rooms in Existing

Facilities, which is available from the National Center

for Environmental Publications and Information (NCEPI) at

the address listed in the introduction to this document

[1003].

Clean and ultraclean—The terms "clean" and "ultraclean"

have been applied to the techniques needed to reduce or

eliminate contamination in trace metals determinations

[1003]. These terms are not used in this method because

of their lack of an exact definition [1003]. However,

the information provided in this method is consistent

with the summary guidance on clean and ultraclean

techniques [1003].

The procedure given in this method for digestion of total

recoverable metals is suitable for the determination of

silver in aqueous samples containing concentrations up to

0.1 mg/L [1003]. For the analysis of samples containing

higher concentrations of silver, succeedingly smaller

volume, well-mixed sample aliquots must be prepared until

the analysis solution contains <0.1 mg/L silver [1003].

Sample preservation—Preservation of samples and field

blanks for both dissolved and total recoverable elements

may be performed in the field at time of collection or in

the laboratory [1003]. However, to avoid the hazards of

strong acids in the field and transport restrictions, to

minimize the potential for sample contamination, and to

expedite field operations, the sampling team may prefer

to ship the samples to the laboratory within two weeks of

collection [1003]. Samples and field blanks should be

preserved at the laboratory immediately upon receipt

[1003]. For all metals, preservation involves the

addition of 10% HNO3 to bring the sample to pH <2 [1003].

For samples received at neutral pH, approx 5 mL of 10%

HNO3 per liter will be required [1003].

Do not dip pH paper or a pH meter into the sample; remove

a small aliquot with a clean pipet and test the aliquot

[1003]. When the nature of the sample is either unknown

or known to be hazardous, acidification should be done in

a fume hood [1003]. 

Store the preserved sample for a minimum of 48 h at 0–4(C
to allow the acid to completely dissolve the metal(s)

adsorbed on the container walls [1003]. The sample pH

should be verified as <2 immediately before withdrawing

an aliquot for processing or direct analysis [1003]. If,

for some reason such as high alkalinity, the sample pH is

verified to be >2, more acid must be added and the sample

held for sixteen hours until verified to be pH <2 [1003].

Highlights from EPA Method 1639: Determination of trace

elements in ambient waters by stabilized temperature graphite

furnace atomic absorption:

This 1996 proposed EPA method provides procedures to

determine dissolved elements in ambient waters at EPA

water quality criteria (WQC) levels using stabilized

temperature graphite furnace atomic absorption (GFAA)

[1003]. It may also be used to determine total

recoverable element concentrations in these waters

[1003]. 

As of March 1997, the EPA 1600 series methods had not yet

been officially approved in 40 CFR for use in NPDES

permits, but the improvements in these methods were

suggested by EPA staff to be wise practice when

attempting low detection limit analyses for metals.

This method was developed by integrating the analytical

procedures contained in EPA Method 200.9 with the

stringent quality control (QC) and sample handling

procedures necessary to avoid contamination and ensure

the validity of analytical results during sampling and

analysis for metals at EPA WQC levels [1003]. This

method contains QC procedures that will ensure that

contamination will be detected when blanks accompanying

samples are analyzed [1003]. This method is accompanied

by Method 1669: Sampling Ambient Water for Determination

of Trace Metals at EPA Water Quality Criteria Levels (the

"Sampling Method") [1003]. The Sampling Method is

necessary to ensure that contamination will not

compromise trace metals determinations during the

sampling process [1003].

Many of the requirements for this method are similar to

those for other EPA 1600 series methods [1003].

This method may be used with the following metals [1003]:

Antimony (Sb), CAS 7440-36-0

Cadmium (Cd), CAS 7440-43-9

Trivalent Chromium, CAS 16065-83-1 

Nickel (Ni), CAS 7440-02-0

Selenium (Se), CAS 7782-49-2

Zinc (Zn), CAS 7440-66-6
For dissolved metal determinations, samples must be

filtered through a 0.45-um capsule filter at the field

site [1003]. The filtering procedures are described in

the Sampling Method [1003]. Except for trivalent

chromium, the filtered samples may be preserved in the

field or transported to the laboratory for preservation

[1003]. Procedures for field preservation are detailed

in the Sampling Method; procedures for laboratory

preservation are provided in this method [1003]. To

determine trivalent chromium, a field preparation step,

which is described in the Sampling Method, is used to

isolate the trivalent chromium [1003].

To determine total recoverable analytes in ambient water

samples, a digestion/extraction is required before

analysis when the elements are not in solution (e.g.,

aqueous samples that may contain particulate and

suspended solids) [1003].

Construction materials—Only the following materials

should come in contact with samples: fluoropolymer (FEP,

PTFE), conventional or linear polyethylene,

polycarbonate, polypropylene, polysulfone, or ultrapure

quartz [1003]. PTFE is less desirable than FEP because

the sintered material in PTFE may contain contaminates

and is susceptible to serious memory contamination

[1003]. Fluoropolymer or glass containers should be used

for samples that will be analyzed for mercury because

mercury vapors can diffuse in or out of the other

materials resulting either in contamination or low-biased

results [1003]. All materials, regardless of

construction, that will directly or indirectly contact

the sample must be cleaned using EPA procedures and must

be known to be clean and metal free before proceeding

[1003].

The following materials have been found to contain trace

metals and must not be used to hold liquids that come in

contact with the sample or must not contact the sample

itself, unless these materials have been shown to be free

of the metals of interest at the desired level: Pyrex,

Kimax, methacrylate, polyvinylchloride, nylon, and Vycor

[1003]. In addition, highly colored plastics, paper cap

liners, pigments used to mark increments on plastics, and

rubber all contain trace levels of metals and must be

avoided [1003].

Serialization—It is recommended that serial numbers be

indelibly marked or etched on each piece of Apparatus so

that contamination can be traced, and logbooks should be

maintained to track the sample from the container through

the labware to injection into the instrument [1003]. It

may be useful to dedicate separate sets of labware to

different sample types; e.g., receiving waters vs.
effluents [1003]. However, the Apparatus used for

processing blanks and standards must be mixed with the

Apparatus used to process samples so that contamination

of all labware can be detected [1003].

Do not dip pH paper or a pH meter into the sample; remove

a small aliquot with a clean pipet and test the aliquot

[1003]. When the nature of the sample is either unknown

or known to be hazardous, acidification should be done in

a fume hood [1003].

Store the preserved sample for a minimum of 48 h at 0–4(C

to allow the acid to completely dissolve the metal(s)

adsorbed on the container walls [1003]. The sample

should then verified to be pH < 2 just before withdrawing

an aliquot for processing or direct analysis [1003]. If

for some reason such as high alkalinity the sample pH is

verified to be > 2, more acid must be added and the

sample held for 16 h until verified to be pH < 2 [1003].

One of the requirements for the alternate total

recoverable digestion procedure is to tightly recap the

container and shake thoroughly [1003]. 

Information related to older drinking water methods from EPA

1996 IRIS database [893]:

Monitoring Requirements: Ground water systems monitored

every 3 years; surface water systems monitored annually;

systems out of compliance must begin monitoring quarterly

until system is reliably and consistently below MCL. 

Analytical Methods: Atomic absorption/ furnace technique

(EPA 213.2; SM 304); inductively coupled plasma (200.7):

PQL= 0.002 mg/L.