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Data bank of environmental chemicals     |     The Finnish Environment Institute (SYKE)
 


21.11.2019

Data bank of environmental properties of chemicals


Chemical
Formaldehyde
CAS-number :
50-00-0
 
Synonyms :
Formaldehydi
formaliini
formalin
formaline
formic aldehyde
methanal
methylaldehyde
methylene glycol
methylene oxide
metyylialdehydi
oxomethane.
oxymethylene
 
Sumformula of the chemical :
CH2O
EINECS-number :
2000018
 
State and appearance :
Colourless gas.
 
Odor :
Characteristic, hay, strawlike, pungent.

USSR: human odour perception; non perception: 0.05 mg/m3;
                                  perception: 0.07 mg/m3;
      human reflex response; no response: 0.07 mg/m3
                       adverse response: 0.084 mg/m3.

Odour index: 5000000 at 20 °C 
(Verschueren 1983).
 
Molecular weight :
30.03
 
Spesicif gravity (water=1) :
0.815  at -20/4 °C
 
Vapor density (air=1) :
1.03 
 
Conversion factor, 1 ppm in air=_mg/m3 :
1.248  mg/m3
 
Conversion factor, 1 mg/m3 in air=_ppm :
0.815  ppm
 
Vapor pressure, mmHg :
10  -88°C
3883  at 25°C, Daubert & Danner 1985
 
Melting point, °C :
-118  -118/-92
-92 
 
Boiling point, °C :
-21  -21/-19
-19 
 
Log octanol/water coefficient, log Pow :
0.35  calc., GEMS 1987
0.35  Sangster 1989
 
Henry's law constant, Pa x m3/mol :
0.033  Dong & Dasgupta 1986
 
Adsorption/desorption :
Formaldehyde gas adsorbs somewhat to clay mineral at high
concentrations of the gas, which is important to its use as a
soil fumigant (De & Chandra 1978).
 
Other physicochemical properties :
Very soluble, up to 55% (Merck Index 1983).
 
Photochemical degradation in air :
Formaldehyde absorbs UV radiation at wavelengths of 360 nm and
longer, so is capable of photolyzing in sunlight (Hampson
1980).

The measured half-life for photolysis as measured in simulated
sunlight is 6.0 hr (Su et al. 1979).

There are two photolytic channels; one producing H2 and CO and
the H and CHO (Lowe et al. 1981).

Based on its rate of reaction with photochemically produced
hydoxyl radicals, formaldehyde will have a half-life of 19
hours in clean air and about half that long an polluted air
(Howard 1989).

The hydroxy radical initiated oxidation of formaldehyde also
occurs in cloud droplets to form formic acid, component of acid
rain (Chameides & Davis 1983).

When formaldehyde is irridiated in a reactor, the half-life is
50 min and 35 min in the absence and precence of NO2,
respectively. 
The primary products formed are formic acid, HCl
and CO (Howard 1989).

Reaction with nitrate radicals, insignificant during the day,
may be an important removal mechanism at night (USEPA 1982).

Photooxidation half-life in air:
7.13hr - 71.3hr,
based upon measured rate constant for reaction with hydroxyl
radical in water (Howard 1991).

Atmospheric photolysis half-life:
1.25hr - 6hr,
based upon measured photolysis for gas phase formaldehyde
irradiated with simulated sunlight; t1/2 calculated for
sunlight photolysis (Howard 1991).
 
Other reactions in atmosphere :
The hydroxy radical initiated oxidation of formaldehyde also
occurs in cloud droplets to form formic acid, component of acid
rain (Chameides & Davis 1983).

When formaldehyde is irridiated in a reactor, the half-life is
50 min and 35 min in the absence and precence of NO2,
respectively. 
The primary products formed are formic acid, HCl
and CO (Howard 1989).
 
Photochemical degradation in water :
In water, formaldehyde is hydrated and the hydrate does not
have a chromophore that is capable of adsorbing sunlight and
photolytically decomposing (Chameides & Davis 1983).

Photooxidation half-life in water:
201d - 22yr,
based upon measured rate constant for reacion with hydroxyl
radical in water (Howard 1991).
 
Half-life in air, days :
0.05  1.25hr - 6hr,
0.25  based upon photolysis half-life in the gas phase,
  Howard 1991
 
Half-life in soil, days :
1d - 7d,
scientific judgement based upon unacclimated aqueous
  aerobic biodegradation half-life,
  Howard 1991
 
Half-life in water, days :
1d - 7d,
in surface water, scientific judgement based upon
  unacclimated aqueous aerobic biodegradation
  half-life,
2d - 14d,
14  in ground water, scientific judgement based upon
  unacclimated aqueous aerobic biodegradation
  half-life,
  Howard 1991
 
Aerobic degradation in water :
Aerobic half-life:
1d - 7d, scientific judgement based upon unacclimated aqueous
aerobic biodegradation screening test data (Howard 1991).
 
Anaerobic degradation in water :
Anaerobic half-life:
4d - 28d, scientific judgement based upon unacclimated aqueous
aerobic biodegradation half-life (Howard 1991).
 
Other information of degradation :
Biodegradation:
  +O2
  ->  HCOOH -> CO2 + H2O
HCHO
  ->  CH3OH -> CO2 + H2O
  +H2

Inhibition of anaerobic sludge digestion; at 100 mg/l; aerobic
degradation; 135 - 175 mg/l (Verschueren 1983).

Solutions containing formaldehyde are unstable, both oxidizing
slowly to form formic acid and polymerizing (Kirk Othmer 1980).

In the precence of air and moisture, polymerization readly
takes place in concentrated solutions at room temperatures to
form paraformaldehyde, a solid mixture of linear
polyoxymethylene glycols cointaining 90-99% formaldehyde (USEPA 
1984).

In dilute aqueous solution formaldehyde exists almost
exclusively as hydrated gem-diol (CH2(OH)2) (Dong & Dasgupta 
1986).

Formaldehyde in aqueous effluent is degraded by activated
sludge and sewage in 48 - 72 hr (Howard 1989).

In a die-away test using water from a stagnant lake ,
degradation was complete in 30 hr under aerobic conditions and
48 hr under anaerobic conditions (Kitchens et al. 1976).
 
Other information of bioaccumulation :
Experiments performed on a variety of fish and shrimp show no
bioconcentration of formaldehyde (Hose & Lightner 1980) (Sills 
& Allen 1979).
 
LD50 values to mammals in oral exposure, mg/kg :
42  orl-mus, Lewis & Sweet 1984
  --
260  orl-gpg, Sweet 1987
800  orl-rat
 
LD50 values to mammals in non-oral exposure , mg/kg :
270  skn-rbt, Lewis & Sweet 1984
  --
87  ivn-rat, Sweet 1987
300  scu-mus
420  scu-rat
270  skn-rbt
 
LC50 values to mammals in inhalation exposure, mg/m3 :
92  ihl-mam, Sweet 1987
590  ihl-rat
 
LDLo values to mammals in oral exposure, mg/kg :
36  orl-wmn, Lewis & Sweet 1984
  --
108  orl-wmn, Sweet 1987
 
LDLo values to mammals in non-oral exposure , mg/kg :
16  ipr-mus, Sweet 1987
595  scu-dog
240  scu-rbt
 
LCLo values to mammals in inhalation exposure, mg/kg :
820  ihl-cat, 8hr, Sweet 1987
900  ihl-mus, 2hr
 
TDLo values to mammals in oral exposure, mg/kg :
200  orl-rat, 1d male, paternal effects
  Sweet 1987
 
TDLo values to mammals in non-oral exposure , mg/kg :
259  ims-mus, 11d preg.
  effects on fertility
  effects on embryo or fetus
240  ipr-mus, 7-14d preg.
  effects on embryo or fetus*
  specific developmental abnormalities
500  ipr-mus, 5d male, paternal effects
intratesticular-dog,1d male,paternal e.
400  intratesticular-rat, 1d male
  effects on fertility
46243  scu-rat, 20d male, paternal effects
1170  scu-rat, tumorigenic
  Sweet 1987
 
TCLo values to mammals in inhalation exposure, mg/kg :
ihl-rat, 24hr, 1-22d preg.
  effects on embryo of fetus
0.035  ihl-rat, 8hr, 60d male, paternal eff.
0.05  ihl-rat, 4hr, 1-19d preg.
  effects on newborn
17  ihl-hmn, sense organs and special senses
  lungs, thorax or respiration
0.3  ihl-man,sense organs and special senses,
  behavioral
  Sweet 1987
 
TCLo values to mammals in inhalation exposure, ppm :
ihl-hmn, Lewis & Sweet 1984
  --
14.3  ihl-mus, rat, tumorigenic
  Sweet 1987
 
Other information of mammals :
Skin and eye irritation data:
skin, human, 0.150 mg, mild;
eye, human, 1 ppm, 6 min nse, mild;
skin, rabbit, 540 mg open, mild;
eye, rabbit, 0.050 mg, 24 hr, severe;
eye, rabbit, 10 mg, severe 
(Sweet 1987).
 
Health effects :
Man: severe toxic effects: 100 ppm = 120 mg/m3, 1min;
symptoms of illness; 30 ppm = 36 mg/m3;
unsatisfactory: 10 ppm = 12 mg/m3.
conc. ppm    exposure time       effects
2-3                              tingling of eyes, nose and
                                 throat;
4-5          10-30 min           irritation; discomfort;
                                 lacrimation; some tolerance 
                                 develops; tolerable for
                                 some,not all;
20           short               discomfort and lacrimation;
12                               severe irritation;
13.8         30 min              nasal and eye irritation
                                 and lacrimation;
4            5 min               severe eye irritation;
1            5 min               8 % of test panel reported
                                 eye irritation;
2            12 min              24 % of test panel reported
                                 eye irritation;
4            5 min               100 % -"-
2-4          5 min               33 %  -"-
0.9-1.6 %    occup.              intense irritation;
             exposure            itching of eyes;
                                 dry and sore throat;
                                 increased thirst;
                                 disturbed sleep
(Verschueren 1983).

Eye irritation threshold: 3 - 10 ppm (Verschueren 1983).
 
Mutagenicity :
Mutation data:
cyt, hmn, lym, 10 mg/l;
dnd, hmn, lug, 0.1 mmol/l;
DNA inhibition, esc, 5 mmol/l;
dnr, esc, 1.95 mg/l;
dns, hmn, hla, 10 nmol/l;
dlt, dmg, orl, 1300 ppm;
mrc, smc, 24 mmol/l;
microbial mutation without S9, microorganisms, 10 ppm;
mma, mus, lym, 25 mg/l;
otr, ham, kidney, 4 mg/l;
sin, dmg, orl, 250 ppm;
sce, ham, ovr, 0.110 mg/l;
sperm morphology, rat, orl, 200 mg/kg
(Sweet 1987).
 
Effects on plants :
305 kg formaldehyde (37 %)/ha when applied to soil depressed
growth of mycorrhizal sour orange (Citrus aurantium) seedlings
(Nemec 1980).
 
Maximum longterm immission concentration in air for plants,mg/m3 :
0.03  VDI 2306
 
Maximum longterm immission concentration in air for plants,ppm :
0.02  VDI 2306
 
Effects on microorganisms :
Bacteria: Escherichia coli, toxic, 1 mg/l (Verschueren 1983).

Toxicity threshold (cell multiplication inhibition test):
(formalin 35% w/w) bacteria (Pseudomonas putida): 14 mg/l
(Bringmann & Kühn 1980a).
 
Effects on wastewater treatment :
Removal/secondary treatment: 57% - 99%,
removal percentages based upon data from a semicontinuous
sewage (low t1/2) and continuous activated sludge (high t1/2)
biological treatment simulator (low t1/2) (Howard 1991).
 
EC50 values to microorganism, mg/l :
19  OECD 209, Klecka et al. 1985
11.6  INT, Dutton et al. 1986
 
LOEC values to algae, mg/l :
0.39  Microcystis aeruginosa, Bringmann &
  Kühn 1976
 
LC50 values to fishes, mg/l :
41  96hr, Branchydanio rerio
15  15 - 32.5, 48hr, Leuciscus idus
32.5  Wellens 1982
  --
84  96hr, Anquilla rostrata
  Hinton & Eversole 1978
  --
24.1  96 hr, Pimephales promelas, Geiger et al. 1990
 
EC50 values to fishes, mg/l :
24.1  96 hr, mbt, Pimephales promelas, Geiger et al. 1990
 
Other information of water organisms :
Ctenopharyngodon idella: LC50, 0.13 d, 160 ml/l;
Cyprinus carpio: LC50, 0.13 d, 197 ml/l
(Rosicky et al. 1986).

Toxicity threshold (cell multiplication inhibition test) 
(35 % w/w): bacteria (Pseudomonas putida): 14 mg/l
algae (Microcystis aeruginosa): 0.39 mg/l
green algae (Scenedesmus quadricauda): 2.5 mg/l
protozoa (Entosiphon sulcatum): 22 mg/l
protozoa (Uronema parduczi Chatton-Lwoff): 6.5 mg/l
(Verschueren 1983).

Scenedesmus, toxic, 0.3 - 0.5 mg/l;
Daphnia toxic, 2 mg/l (Verschueren 1983).

Toxicity threshold (cell multiplication inhibition test):
(formalin 35% w/w)
green algae (Scenedesmus quadricauda): 2.5 mg/l
protozoa (Entosiphon sulcatum): 22 mg/l
(Bringmann & Kühn 1980a).
 
Other effects on aquatic ecosystems :
Reduction of amenities:
taste and odour caused at 50 mg/l;
osour threshold: average; 49.9 mg/l; range: 0.8 - 102 mg/l
(Verschueren 1983).

References
142Bills, T.D. et al. 1977. Formalin: Its toxicity to nontarget aquatic organisms, percistence and removal with activated carbon. Investigations in fish control. No. 75. U.S. Dept. Int., Fish & Wildlife Service, Washington, D.C.
187Bringmann, G. & Kühn, R. 1976. Vergleichende Befunde der Schadwirkung wassergefährdender Stoffe gegen Bakterien (Pseudomonas putida) und Blaualgen (Microcystis aeruginosa). Gwf-Wasser-Abwasser 117(9).
188Bringmann, G. & Kühn, R. 1980a. Comparison of the toxicity thresholds of water pollutants to bacteria, algae and protozoa in the cell multiplication inhibition test. Water Res. 14: 231 - 241.
3031Chameides, W. L. & Davis, D. D. 1983. Nature 304: 427 - 429.
2994Daubert, T. E. and Danner, R. P. 1985. Data Compilation Tables of Properties of Pure Compounds. pp 450. American Institute of Chemical Engineers.
3032De, S. K. & Chandra, K. 1978. Sci Cult. 44: 462 - 464.
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2425Dutton, R. J. et al. 1986. Rapid test for toxicity in wastewater systems. Toxicity Assessment 1: 147.
3297Geiger, D. L. et al. 1990. Acute toxicities of organic chemicals to fathead minnows (Pimephales promelas) Vol 5. Center for Lake Superior Environmental Studies, University of Winsconsin-Superior, Superior, Winconsin, U.S.A. 332.
3034GEMS. 1987. Graphical Exposure Modeling System. CLOGP. USEPA
3039Hampson, R. F. 1980. Chemical kinetic and photochemical data sheets for atmospheric reactions. FAA-EE-80-17.
582Hinton, M.J. & Eversole, A.G. 1978. Toxicity of ten commonly used chemicals to American eels. Proc. Ann. Conf. S.E. Assoc. Fish & Wildl. Agencies. 32: 599.
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3040National Research Council. 1982. Formaldehyde and other aldehydes. USEPA 600/6-82-002.
1726Nemec, S. 1980. Effects of 11 fungicides on endomycorrhizal development in sour orange. Can. J. Bot. 58(5): 522 - 526.
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3041Sills, J. B. & Allen, J. L. 1979. Prog. Fish Cult. 4: 67 - 68.
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