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EC number: 200-087-7
CAS number: 51-28-5
(2,4-DNP) production and its use in the manufacture of dyes
are the main sources of release in the environment through
various loss and waste streams. Below some specific releases
to several environmental compartments are mentioned,
followed by a more in depth analysis of the fate of 2,4-DNP
in each specific compartment.
are released to the air from manufacturing plants and
facilities that use them for the production of explosives,
dyes, wood preservatives, pesticides. (HSDB 1994; TRI92
Sources of 2,4-DNP in atmosphere
could be automobile exhaust dusts, pesticides, hazardous
waste disposal sites and photochemical reactions of benzene
with nitrogen oxides (Nojima et al. 1983) that thus can be
considered a secondary source of environmental exposure.
into surface water can occur because of releases from
the above mentioned production facilities and by industries
that manufacture other products using 2,4-DNP.
has for instance been detected in the waste water
from nitrobenzene-manufacturing plants (Patil and Shinde
1988), industries or plants that are explosives producers
(McLuckey et al. 1985), dye-manufacturing plants (Games and
Hites 1977), and sewage treatment plants where the influent
waters already contain dinitrophenols (DeWalle et al. 1982).
Since 2,4-DNP is also used to produce picric acid,
picramide, and photographic developer (diaminophenol
hydrochloride) and in preserving wood (Hawley 1981), waste
waters or land runoffs from these industries may also
release 2,4-DNP to surface water.
may be released in soils in the vicinity of the sites
where they are manufactured and used by wet and dry
deposition or from waste water release. Dinitrophenols were
found in the soil of a decommissioned wood preserving
facility (EPA 1988a).
substances with vapour pressures of 10^-4 to 10^-8 mmHg at ambient
temperature should exist partly in the vapour and partly in the
particulate phase in the atmosphere (Eisenreich et al. 1981).
According to a model of gas/particle partitioning of semi-volatile
organic compounds in the atmosphere, 2,4-DNP, which has a vapour
pressure of 1.49 X10^-5 mm Hg at 18 °C, is expected to exist as a vapour
in the ambient atmosphere.
indicate that photo-degradation may be an important fate
process, although the kinetic of these reactions are unknown
(Atkinson et al., 1992).
Vapour-phase 2,4-DNP is degraded in
the atmosphere by direct photolysis by sunlight at > 290 nm (HSDB,
Sadtler Res lab, 2012) and by the reaction with
photochemically-produced hydroxyl radicals (SRC) with an half-life
estimated of 28 days (degradation rate constant OH radicals of
5.76 x 10^-13 cm3).
Conversely, reaction with nitrate
radicals should not be a significant environmental fate (by
structural analogy) (Grosjean D. 1985).
The presence of dinitrophenols in
air is < 100%. This is explained in a study of Nojima K, Kawaguchi
A, Ohya T, et al. 1983 where the detection of 2,4-DNP by GC in air
are indirect indications of the partially sorbing in
since dinitrophenols are expected to be present partly in the
particulate phase in the air, the reaction rate in air is expected
to be even slower than the estimated value for the gas phase
reaction (Atkinson R. et al., 1988), so significant removal of
dinitrophenols from the atmosphere due to photochemical or other
chemical reactions is not likely.
conclusion, DNP exists as a vapour in the atmosphere. Direct
and indirect photodegradation can occur, however the main
elimination pathway seems to be sorption to particulate matter in
air with subsequent wet and dry deposition of DNP. The
presence of DNP in rain and snow was experimentally verified by
Alber et al. 1989; Cape1 et al. 1991; Levsen et al. 1990). In
fact, the detection of 2,4-DNP in rain, and snow showed that at
least partial removal of these compounds occurs by physical
processes (Alber M, Bîhm HB, Brodesser J, et al. 1989).
COMPARTMENT (incl. sediment)
photochemical nor other chemical processes have been identified as
significant for the transformation/degradation of dinitrophenols
in natural waters (Callahan et al. 1979; Lipczynska-Kochany 1992;
Tratnyek and Hoigne 1991; Tratnyek et al. 1991). Furthermore, the
direct photolysis of 2,4-DNP in water is too slow to be an
important environmental fate process (Lipczynska-Kochany E, 1991).
conclusion has been explained in several studies (Tratnyek et al.
1991- Mabey WR, et al. 1981), where the main conclusion was that
the photo transformation of 2,4-DNP would not be important in
water (half-life of ≈500 days). This value is based on the
reaction between 2,4-DNP, singlet oxygen (O2) and peroxy radicals
(RO2) concentrations (the rate constant of 2,4-DNP’s reaction with
singlet oxygen concentrations is 4.05 x 10^5molar-second and the
estimated average of the singlet oxygen concentration in typical
eutrophic fresh water is 4 x 10^-14molar).
concentrations of singlet oxygen and peroxy radicals in typical
eutrophic waters are low (10^-12 and 10^-9 molar, respectively).
Hence, the reaction of hydroperoxy radicals (HO2) with 2,4-DNP,
producing a ring hydroxylated products, would not be significant
(Mill and Mabey 1985).
may be also photoreduced to 2-amino-4-nitrophenol in the presence
of ascorbic acid or ferrous ions, and the reaction is sensitized
by chlorophyll. The possibility of such photo reduction exists in
natural water in which the suspended reducing matter may act as a
reducing agent and humic substances or algae may serve as a
sensitizer (Massini P, Voorn G. 1967).
is not expected to undergo hydrolysis in the environment due to
the lack of functional groups that hydrolyse under environmental
conditions (Lyman WJ et al., 1990).
sorption and subsequent transport of dinitrophenols from water to
suspended solids and sediment would be significant in natural
waters that are acidic and/or have high organic matter and clay
content. In studies (Kaufman, 1976 and Callahan et al., 1979) it
has been indicated that the sorption of dinitrophenols by soil or
sediment would depend on their organic carbon content, clay
content, and pH.
increase in clay and organic carbon content and a decrease in pH
would increase the amount sorbed.
may be the most important process of loss for dinitrophenols in
results from a Japanese MITI test biodegradation, where the
2,4-DNP reached 0% of its theoretical BOD in 4 weeks using an
activated sludge inoculum (aerobic biodegradation) (NITE; Chemical
Risk Information Platform (CHRIP), in general, complete or partial
biodegradation of 2,4-DNP was observed in several aquatic systems.
half-life in aerobic waters for biodegradation has been reported
to be 68 days, in anaerobic water 2.8 days (Capel PD, Larson SJ,
different microbial systems, under aerobic conditions
biodegradation was observed in mixed microorganisms from activated
sludge (Kincannon et al. 1983a, 1983b; Patil and Shinde 1989;
Pitter 1976), enriched sewage (Brown et al. 1990; Wiggins and
Alexander 19SS), adapted sediment from rivers or waste lagoons
(Barth and Bunch 1979; Chambers et al. 1963; Tabak et al. 1964).
several studies with activated sludge previously adapted to
mineralize low concentrations of dinitrophenols (Jo KW,
Silverstein J, 1998) and under methanogenic conditions with
anaerobic digester sludge (Battersby and Wilson 1989; O’Connor and
Young 1989) biodegradation was observed, but this activity
diminished at higher concentrations of 2,4-DNP.
effects were explained in the IUCLID section 6.1.7
(ecotoxicological information for microorganisms).
fact toxic level of c.a 10 -20 mg/L of 2,4-dinitrophenol was
defined (O'Connor and Young, 1989) and a detailed study on sludge
activity indicates a NOEC (no inhibitory effect) of 4 ppm.
is also biodegraded by several pure cultures of microorganisms.
Usually, the pure cultures are able to biodegrade 2,4-DNP after a
certain adaptation period and as long as the concentration of
2,4-DNP is below a certain toxic level. The degradation pathway
depends on the microorganisms and the conditions of aeration.
with aerobic organisms and aerobic conditions, the biodegradation
proceded by replacement of nitro groups by hydroxyl groups and
liberation of nitrite, or by hydroxylation of the aromatic ring
positions 3, 5, or 6 (Raymond and Alexander 1971).
pure culture studies are important for establishing degradative
pathways, they do not reflect real environmental situations where
mixed microorganisms and different nutritional conditions are
or partial biodegradation of 2,4-DNP was observed also in field
conditions, as in an aeration lagoons and settling ponds.
water compartment for 2,4-DNP, estimated and experimental BCF
values are available.
meaning of BCF values indicates the possibility of
bioconcentration in the aquatic compartment.
overall range of BCF measured in salt water is from 3.0 to 16 (EPA
databank). Additional studies measured BCF values of < 0.4 - 0.7
and < 3.7.
BCFs suggest that the potential for bioconcentration in aquatic
organisms for 2,4-DNP is low (SRC) (NITE; Chemical Risk
Information Platform (CHRIP)). Estimated BCF has a value of 0.56.
The concentration of 2,4-DNP in fish may be even lower than its
concentration in water. (McCarty LS, Mackay D, Smith AD, et al.
1993). Furthermore, bioconcentration of dinitrophenols from water
to aquatic organisms and from soil to plants is not expected to be
data were located on the biomagnification potential for
dinitrophenols in predators that consume contaminated prey (EPA
1986a; O’Connor et al. 1990).
has been speculated that 2,4-DNP in soil may be reduced to
2-amino-4-nitrophenol by sunlight in the presence of a reductant,
such as ferrous ions and a sensitizer, such as chlorophyll
(Kaufman 1976; Overcash et al. 1982; Shea et al. 1983). However it
seems unlikely that sunlight would penetrate the soil surface
values collected suggest that 2,4-DNP is expected to have high
mobility in soil (Martins JM, Mermoud A: J Contam Hydrol, 1998).
Measured Koc values are in the range of 13.5 - 16.6 and estimated
value is 284.3 L/kg (Kow method). Moreover the pKa of 2,4-DNP is
4.09, which indicates that this compound will exist primarily as
an anion in moist soil surfaces and anions are expected to have
very high mobility in soils (SRC).
of 2,4-DNP from moist soil surfaces is not expected to be an
important fate process (SRC) since the anion will not volatilize.
The neutral species has a Henry's Law constant of 8.71E-003
Pa-m3/mole at 20°C and a vapour pressure of 1.49 X10-5mm Hg at 18
°C (Wild and Jones (1992). The possibility of volatilization of
phenolic compounds in soil via co-distillation with water has been
suggested and release to air via aerosol formation is possible
(Kincannon and Lin, 1985).
mobility of dinitrophenols in soils decreases with increase in
acidity, clay, and organic matter content. The ionized form is
more water soluble and moves faster through soil. The transport of
dinitrophenols from soil to groundwater may also occur via
leaching. The amount of DNP leached depends on the dinitrophenol
adsorption capability of soils. 2,4-DNP is a moderate weak acid
that is expected to be highly labile (leachable and plant
available) in higher-pH soils. Several studies defined that
adsorption of phenols in soil increases with a decrease in pH and
an increase in organic carbon, goethite (one of the most common
iron oxides in soil) and clay content (Hudson-Baruth and Seitz
1986; Kaufman 1976; O’Connor et al. 1990; Shea et al. 1983; Stone
et al. 1993).
may be the most significant process for destroying dinitrophenols
biodegradation half-life of 2,4-DNP in an acidic soil was reported
of 32.1 days and the biodegradation half-life in a basic soil as
4.6 days (Loehr RC, 1989).
on the type of soil (pH, organic matter content), the length of
acclimation phase, as well as the initial concentration, the
residence time of dinitrophenols for the aerobic biodegradation of
soil may vary from 8 to 120 days (Kincannon and Lin 1985; Loehr
1989; O’Connor et al. 1990).
can be biodegraded by isolated culture proceeding of the reduction
of the nitro group or displacement of a nitro group by a hydroxyl
group with the release of nitrite ions (Kohping GW, Wiegel J.
1987, Shea PJ, Weber JB, Overcash MR., 1983). However, high
concentration 2,4-DNP (see IUCLID section 6.1.7) may be toxic to
the degrader microorganisms.
biodegradation of dinitrophenols in soils will occur also by
bacteria in multiphasic mineralization kinetics (involving several
slow types of anaerobic reaction anaerobic to methane and carbon
dioxide) (Schmidt SK, Gier MJ. 1990, Young LY. 1986). Pure culture
of the fungus Fusarium oxysporum, pure cultures of Nocardia alba,
Arthrobacter and Corynebacterium simplex are all able to reduce
2,4-DNP (Overcash MR et al, 1982).
loss of dinitrophenols from soil could occur by plant uptake.
Bioaccumulation factor (concentration in plant over concentration
in soil) in lettuce, carrot (tops, peels, and root), hot pepper
foliage, and fruits is < 0.01 at a soil pH of 6.7-7.2.
dinitrophenols undergo metabolism in plants, plants accumulation
of dinitrophenols due to uptake would not be significant. Since
the concentration of the non-ionized form is only <0.25% of total
DNP at pH 6.7, the soil pH has to be considerably lower to permit
the uptake of the non-ionized form in a significant way in plants
(O’Connor GA, Lujan JR, Jin Y. 1990).
fact, in a Shea PJ, Weber JB, Overcash MR., 1983 study it has been
demonstrated that the uptake and the translocation could be
significant in soil with low pH where the concentration of
non-ionized dinitrophenols (more readily adsorbed than the ionized
form) are already higher.
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