Benzo(ghi)perylene

191-24-2

Main constituent in the residues from coal hydrogenation.

Large pale yellow-green plates.

276.34

Evaporation of lower-molecular-weight PAHs may be significant
only in a clear, rapidly flowing shallow stream (Sax 1986).

Movement via sediment is an important transport process.

An exchange equilibrium exists in natural water systems between
absorbed and soluble PAHs. 
Although the particulate form is
favored, a significant fraction of the PAH will be dissolved
except in systems that are very heavily contaminated by PAHs
(Sax 1986).

Insoluble.

The most common photooxidation product of PAHs
in solution in an endo peroxide. 
Dealkylation, ring cleavage,
and other reactions ensue following photolysis or pyrolysis of
these peroxides. 
Frequently, only quinones are isolable.

Photodimers may result in some cases. 
Adsorbed PAHs are more
reactive than in solution (Sax 1986).

Photooxidation half-life in air:
3.21hr - 0.321hr, scientific judgement based upon estimated 
rate constant for reaction with hydroxyl radical in air (Howard 
1991).

Photolysis in an aquatic environment may be an important fate
process, especially for the dissolved portion (Sax 1986).

Hydrolysis is not significant (Sax 1986).

Ozone and chlorinating agents oxidize polycyclic aromatic
hydrocarbons to quinones, diacids, and nuclear and side-chain
oxidation products. 
Chlorinating agents also produce
chlorine-substituted derivatives. - 
Oxidation of any PAH by
chlorine and ozone, when used for the disinfection of drinking
water, forms quinones. 
The half-life for the reaction of
chlorine with all PAHs is less than 0.5 hr. -  
Treating
benzo(ghi)perylene with 2.2 ppm free chlorine at 20 ° C and pH
6.8 for 15 minutes reduced its concentration by 50 %. -  
A
half-life of benzo(ghi)perylene in the presence of ozone was
calculated to be approximately 1 minute. 
It requires 197 mg
granular activated carbon per litre to reduce the concentration
of benzo(ghi)perylene from 1.0 to 0.1 ppm at pH 7.0 (Sax 1986).

Aerobic half-life:
650d - 590d, based upon aerobic soil die-away test data at 
10-30°C (Howard 1991).

Anaerobic half-life:
7.1yr - 6.5yr, based upon aerobic soil die-away test data at 
10-30°C (Howard 1991).

PAHs deposited in sediments are less subject to photochemical or
biological oxidation, especially if the sediment is anoxic. 
Sedimentary PAH is therefore quite persistent and may
accumulate to high concentrations (Sax 1986).

Airborne particulate PAHs can persist at relatively high
concentrations in aerosols transported for long distances. 
The
atmosperic persistence is longer than would be predicted from
laboratory photooxidation studies. 
On the other hand, The
National Academy of Sciences (1972) proposed that the chemical
half-life of PAH's in the atmosphere may be limited to hours or
days (Sax 1986).

Biodegradation is probably the ultimate fate process for
benzo(ghi)perylene (Sax 1986).

PAHs with 4 or more aromaric rings are degraded slowly by
microbes. 
However, the concentrations of bacteria and fungi
capable of oxidizing hydrocarbons are extremely low in all but
heavily polluted fresh and marine waters. 
Most species cannot
use PAHs as a sole carbon source. 
Microbial oxidation of PAHs
requires oxygen an will not proceed in anoxic sediments or water
(Sax 1986).

During a 7 day incubation period with bacterial suspension of 1
- 2 ppm, an approximately 1 % emulsion of benzo(ghi)perylene
was degraded 60 % (Sax 1986).

The soil bacterium Bacillus megaterium was found to metabolize
benzo(ghi)perylene and certain other PAHs at the same rate
regardless of concentrations or solubility in the medium (Sax
1986).

There are large differences among aquatic species in their
ability to absorb and assimilate PAH from food. 
Polychaete
worms have a very limited ability; fish show limited and
variable absorption from the gut; and crustaceans readily
assimilate PAH. 
Assimilated PAHs are metabolized and excreted
rapidly. 
For biomagnification to occur, a substance must be
relatively resistant to metabolism or exretion (Sax 1986).

PAHs with 4 or more aromatic rings are metabolized slowly by
multicellular organisms. Since the log octanol/water partition
coefficient is high and metabolism is slow, benzo(ghi)perylene
is probably bioaccumulated. In most cases PAHs are less
bioavailable when complexed to colloidal organic materials or
absorbed to organic or inorganic particulates than when in
solution or in fine dispersion in water (Sax 1986).

Bioconcentration factor (other organisms):
68200, aquatic organisms containing 7.6 % lipids 
(Sax 1986).

Not carcinogenic, but a cocarcinogen. 
PAHs presumably can be
absorbed from ingestion, inhalation, and skin contact (Sax
1986).

Polychlorinated PAHs are probably highly toxic to aquatic
organisms and persistent in the environment as are
polychlorinated biphenyls and polychlorinated naphthalenes.

Chlorination for purification of wastewaters or drinking waters
containing high concentrations of PAHs may be inadvisable.

Activated sludge treatment is unable to oxidize PAHs within
normal retention times. -  
An overall reduction of
benzo(ghi)perylene concentration of 88 % from that in the
intake river water (0.072 ppb) following water purification
steps of holding in a reservoir, filtration, and chlorination
was reported (Sax 1986).

Lethal threshold concentration (LT50):
Daphnia magna: 0.0002 mg/l, 0.58 days (Newsted & Giesy 1987).