Dibutyl phthalate

84-74-2

Plasticizer manufacturing; plastics manufacturing; recycling
and processing. 
Insect repellent for the impregnation of
clothing. 
Explosives.

Colourless oily liquid will sink and associate with sediments.

Very little will dissolve.

Mild odour.

278.38

The volatilization half-life for DBP from stirred seawater
solution 1 m deep is 28 days (Atlas et al. 1982).

Using the calculated Henry's Law constant, it is estimated that
the half-life for DBP in a river 1 m deep with a 1 m/sec
current and a 3 m/sec wind is 47 days days, with the rate being
controlled by the diffusion through the air (Lyman et al. 1982).

The Henry's Law constant of 0.27 Paxm3/mol indicates that DBP 
will only slowly volatilize from surface waters, i.e. virtually 
all of the DBP will reman in the water phase at equilibrium (EU 
RA Report 2003).

The partition coefficient of DBP between montmorillonite,
kaolinite,and calsium montmorillonite and seawater was 40, 20
and 4, respectively at high concentrations (3-4 ppm) and 2, 4
and 36, respectively at low concentrations (ca 20 ppb)
(Sullivan et al. 1981).

The partition coefficient between marine sediment (ca 1%
organic carbon) and seawater was 149 (Bouwer et al. 1981).

Despite its moderate adsorption to soil, DBP has been found in 
ground water underlying rapid infiltration sites at high 
concentrations (Tomsom et al. 1981).

DBP forms a 1:1 complex with fulvic acid which is a 
water-soluble humic material formed from the decomposition of 
plants. 
The water soluble complex so formed may act as a 
vehicle for the mobilization and transport of DBP as wellas 
altering its reactivity (Matsuda & Schnitzer 1971).

Flammability: slight when exposed to heat or flame. 
Toxic
combustion products: slight hazard. 
Practically insoluble in
water (Sax 1986).

Photooxidation half-life in air:
2.5d - 7.4hr, scientific judgement based upon estimated rate
data for hydroxyl radicals in air (Howard 1991).

Photochemically produced hydroxyl radicals in the atmosphere
will react with vapor phase DBP by aromatic ring addition and
hydrogen  atom abstraction with an estimated half-life of
18.4 hr ((GEMS 1987).

Photooxidation by OH radiacals contributes to tj he elimination 
of DBP from the atmosphere. 
The experimental degradation rate 
constant amounts to about 1.8x10-12 cm3/molxsec corresbonding 
to a half-life of 21.4 hoursat an average OH concentration of 
500,000 molecules/cm3. 
Vapour phase reactions of DBP with 
photochemically produced hydroxyl radicals were estimated with 
a QSAR. 
The overall OH rate constant for DBP was estimated to 
be 8.7x10-12 cm3/molxsec. 
This value corresponds to an 
atmospheric half-life of about 1.8 days (EU RA Report 2003).

Aquatic photolysis half-life:
144d, scientific judgement based upon estimated maximum
aqueous photolysis rate data (2.0 x 10-4 hr-1).

Photooxidation half life in water:
12.2yr - 2.4yr, scientific judgement based upon estimated rate
data for alkylperoxyl radicals in aqueous solution
(Howard 1991).

The estimated photolysis half-life in natural waters is 144 
days. 
The estimated half-life due to reaction with alkoxy 
radicals in natural waters is 456 days (Wolfe et al. 1980).

Hydrolysis very slow (Giam et al. 1984).

First-order hydrolysis half-life:
10yr, based upon overall rate constant (1.0 x 10-2 mol-1 s-1)
at pH 7 and 30 °C (Howard 1991).

The hydrolysis of DBP at neutral pH has a half-life of 10 year. 

(Callahan et al. 1979).

The hydrolysis rate increases with pH and at pH 9 the estimated 
half-life is 76 days (Wolfe et al. 1980).

Aerobic degradation in freshwater hydrosoil: 98 % alter 5 days
incubation (Verschueren 1983).

Aerobic half-life:
23d - 1d, scientific judgement based upon unacclimated aerobic 
river die-away test and soil grab sample data (Howard 1991).

Anaerobic half-life:
23d - 2d, scientific judgement based upon unacclimated 
anaerobic grab sample data for soil and sediment (Howard 1991).

Confirmed to be biodegradable (Anon. 1987).

Degradation of di-butyl-phthalate:
*-------------------------------------------------------------*
ENVIRONMENT      INIT.CONC   REDOX-    TEMP   DEGRADATION   REF
                    mg/l     COND.      °C    %/day  t1/2
*-------------------------------------------------------------*
water                 5     aerobic     25    100/7          a
water                10     aerobic     25    100/7          a
freshwater sediment   1     aerobic     22      5/1          b
freshwater sediment   1     aerobic     22     95/7          b
freshwater sediment   1     aerobic     22     97/30         b
freshwater sediment   1     anaerobic   22      0/1          b
freshwater sediment   1     anaerobic   22     47/7          b
freshwater sediment   1     anaerobic   22     98/30         b
sludge              100     aerobic     30    >90/20         c
soil                0.00045 aerobic     20      0/14         d
soil (adapted)      0.00045 aerobic     20     75/14         d
soil                500     aerobic     30    100/15         e
soil                500     anaerobic   30     60/30         e
soil               1000     aerobic      4      2/53         f
soil               1000     aerobic     23     32/53         f
soil               1000     aerobic     23     88/200        f
soil               1000     aerobic     30     78/53         f
soil               1000     anaerobic   23     69/53         f
soil               1000     anaerobic   23     98/200        f
soil                  1.4   aerobic     25    100/1          g
soil (sterile)        1.8   aerobic     25     70/5          g
soil                  1.4   aerobic     25    100/2          g
soil (sterile)        1.1   aerobic     25     72/5          g
soil                  5.1   aerobic     10        -   5.6    h
*-------------------------------------------------------------*
a) Tabak et al. 1981               e) Shanker et al. 1985
b) Johnson & Lulves 1975           f) Inman et al. 1984
c) Engelhardt et al. 1977          g) Russell et al. 1985
d) Hutchins & Ward 1984            h) Lökke 1984
(Anon 1987b).

Easily biodegradable both in aerobic and anaerobic ways (Kaare
Jensen et al. 1987).

Easily degradable (Anon 1989).

In sediment and soil relatively slow degradation (Giam et al
1984).

Degradation products of special interest: monobutyl phthalate,
assumed toxic metabolite in Artemia (Hudson et al. 1981).

DBP is significantly biodegraded in biodegradation tests
utilizing sewage and activated sludge inoculum. 
In a shake
flask biodegradation test after 28 days 68 to >99% of the DBP
had disappeared and  80.6 to >99% was converted to CO2. 
The lag
period averaged 4.5 days (Sugatt et al. 1984) (Howard 1989).

In an aerobic pondwater-sediment mixture 97% degradation was
noted in 5 days. 
The intermediate products of degradation were
the mono-n-butyl ester and phthalic acid. 
Biodegradation under
anaerobic conditions was slower with 41% and 98% degradation
occurring after 7 and 30 days, respectively, in a
sediment-pond water mixture (Johnson & Lulves 1975).

DBP is completely mineralized in digested sludge in 2 weeks
under anaerobic conditions and 28% was lost after 7 days ina
composting mixture (Shelton et al. 1984) (Snell Group 1982).

There is ample evidence that DBP is ready biodegradable under 
aerobic conditions. 
Also a BOD5:COD ratio of 0.63 obtained with 
a non-adapted inoculum indicates that DBP may be regarded as 
readily biodegradable. 
It is also demostrated that DBP is 
readily biodegradable in a modified Sturm test (EU RA Report 
2003).

Food chain contamination potential: ester is taken up rapidly
and magnified in crustacea, but clears after 10 days. 
Negative
(Sax 1986).

DBP is rabidly metabolized in fish within 4 hr, 75% of the residue 
from a channel catfish was inthe form of monobutyl phthalate 
(Johnson et al. 1977).

The log BCF in American oyster, Brown shrimp and Sheepshead minnow 
were 1.50, 1.22 and 1.07, respectively 
(Wofford et al.1981).

Bioconcentration factor (crustaceans):
5000, Palaemonetes kadiakensis (Verschueren 1983).
140, 10d, Gammarus pulex (Thuren & Woin 1988).
1400, 14d, Gammarus pseudolimnaeus, total
(Mayer & Sanders 1973).
5000, 7d, Daphnia
6500, 7d, Gammarus pseudolimnaeus
(Sanders et al. 1973).
 
Bioconcentration factor (other organisms):
6600, 7d, Chironomus (Sanders et al. 1973).

The high Kow of DBP indicates that the substance has a 
potential for bioaccumulation. However the actual degree 
of bioaccumulation in vivo will be determined by the 
metabolisation and the elimination rate of the substance (EU RA Report 2003).

Induces many biochemical effects, e.g. increases liver
cytochrome P-450, reduces serum albumine, changes active K-ion
transportation via membranes (Giam et al. 1984).

Man, oral, lowest dose which affects the central nervous
system: 140 mg/kg (Sax 1986).

Direct contact; low, eye, skin (Sax 1986).

Negative in Drosophila-test. 
No x-chromosome mutations noted in
male fluit flies fed sublethal doses (Sax 1986).

cyt, ham, fbr, 30 mg/l, 24 hr (Sax 1986).

Positive. 
Teratogenic effects demonstrated in rats (Sax 1986).

Plant (corn, Zea mays) heights and shoot wts. were not
significantly reduced at 200 ppmw; but at 2000 ppmw DBP, plant
height was reduced by 17 % and plant shoot wt. by 25 %. 
The low
levels (1.24 ppm) of DBP found in plants grown in soil
containing 2000 ppmw (Shea et al. 1982).

DP affected soybean germination at 200 ppm (dry soil basis)
(Overcash et al. 1982).

Induces chlorosis in green leafs (Løkke & Rasmussen 1983).

May flog filters and exchange beds (Sax 1986).

EC50, 24 hr, 2.2 mg/l, rpd, Tetrahymena pyriformis (Yoshioka et
al. 1985).

EC50, 96 hr, 5.8 mg/l, Chironomus sp. 
(Cox & Moran 1984).

Corophium sp., colonisation, 0.34 mg/l (Tagatz et al. 1983).

Daphnia, reproduction, reversible effect (Springborn 1984).

Daphnia, reproduction (McCarthy & Whitmore 1985).

Microcosmos, 14 d, effective concentration, 3.7 mg/l (Tagatz et
al. 1983).

Persistency: Certain bacterial strains will degrade n-butyl
phthalate but only when the initial concentrations are low. -

Degradation will take place in freshwater hydrosoil also
through the enzymatic action of microorganisms. 
Anaerobic
conditions will slow biodegradation (Sax 1986).

Air pollution: There will be no appreciable vapor. 
At high
temperatures, there will be carbon dioxide (Sax 1986).