| Environmental Impact | The pattern of benz(a)anthracene (BA) release into air and water is quite general since it
is a universal product of combustion of organic matter. Both in air and water it is largely
associated with particulate matter. When released into water it will rapidly become adsorbed to
sediment or particulate matter in the water column, and bioconcentrate into aquatic organisms. In
the unadsorbed state, it will degrade by photolysis in a matter of hours to days. Its slow
desorption from sediment and particulate matter will maintain a low concentration of BA in the
water. Because it is strongly adsorbed to soil it will remain in the upper few centimeters of soil
and not leach into groundwater. BA will very slowly biodegrade when colonies of microorganisms
are acclimated but this is too slow a process (half-life ca 1 yr to be significant). Benz(a)anthracene
in the atmosphere will be transported long distances and will probably be subject to photolysis and
photooxidation although there is little documentation about the rate of these processes in the
literature. Humans will be exposed to benz(a)anthracene in ambient air, particularly in industrial
areas, from stoves, cigarette smoke, food (particularly when smoked or charcoal broiled), and
drinking water.
|
|---|
| Environmental Fate | TERRESTRIAL FATE: When benz(a)anthracene is spilled on soil it will remain in the
surface layers since it is strongly adsorbed. Although benz(a)anthracene in the free state will
photolyze when exposed to the sun, there is no evidence that the adsorbed molecules
photodegrade. Biodegradation will occur very slowly, having a half-life of close to a year in
previous spill sites and much longer otherwise.
AQUATIC FATE: When benz(a)anthracene is released into water it will rapidly sorb to the
sediment and particulate matter in the water column including phytoplankton and zooplankton.
Therefore, high initial concentrations are rapidly reduced (few hours). However low
concentrations caused by desorption can last almost indefinitely . The dissolved
benz(a)anthracene will undergo photolysis (half-life hours to a few days) and in eutrophic bodies
of water, oxidation by alkylperoxy radicals may be important. The relative contribution of
sorption and photolysis to benz(a)anthracene removal will depend on the type of aquatic
system . Biodegradation will be unimportant except in the sediment in which the half-life may
be somewhat under a year if acclimated colonies of microorganisms exist from previous spills. In a
microcosm experiment which simulated shallow coastal waters of the northeast US, 29% of the
benzo(a)anthracene had respired to CO2 while 21% was unchanged . When a crude oil
dispersion was placed on top of a water column in a controlled ecosystem enclosure in Saanich
Inlet, Canada, the benz(a)anthracene concentration in the water column decreased exponentially,
declining to half its initial concentration in 4-5 days . Benz(a)anthracene will bioconcentrate in
aquatic organisms.
ATMOSPHERIC FATE: Benzo(a)anthracene (BA) is found in the atmosphere both as the free
vapor and adsorbed to particulate matter. Polyaromatic hydrocarbons are found concentrated in
submicron particles and aerosols. These particles will be transported but are subject to
gravitational settling and scavenging by rain and snow. The estimated half-lives of these particles
in the atmosphere has been estimated to be 5-30 days during which time they can be transported
to remote regions(1,2). Although BA will be subject to photolysis and phtotooxidation, no studies
could be found in the literature dealing with its photolysis or photooxidation in the free vapor
phase or when adsorbed to small particles.
|
|---|
| Drinking Water Impact | DRINKING WATER: Benz(a)anthracene has been detected in finished water from 5
water treatment plants in Ontario, Canada at a range of not detected to 2.6 parts/trillion, however,
it was not separable from chyrsene and triphenylene so these values are upper limits . A sample
from Ottawa, Canada contained 3.3 parts/trillion benz(a)anthracene . 4 of 5 samples of Nordic
tap water were pos at 0.12 to 1.5 parts/trillion . German drinking water samples ranged from 1
to 23.2 parts/trillion (4,5). In the heavily industrialized area of Kitakyushu, Japan,
benz(a)anthracene was not detected in tap water .
It has been identified in surface water, river water (0.4 to 30.6 ng/l); tap water (0.4 to 10.7
ng/l) rainfall (3.2 to 12.3 ng/l); subterranean water (0 to 1.3 ng/l); & wastewater (0.5 to 4.9 ug/l)
.
SURFACE WATER: Detected, not quantified in 1 of 204 water samples from 14 heavily
industrialized US river basins . Surface water from an unspecified source contained 4.3 to 185
ppm . Major rivers in Germany 4.3 to 385 parts/trillion .
SEAWATER: Dohkai Bay, Kitakyushu area Japan - detected, not quanitified(1,2).
RAIN WATER: Great Lakes ecosystem sampling - range 2.6 to 3.1 parts/trillion, mean 3
parts/trillion . Norway - detected, not quantified in 6 of 24 samples, however it was not
separable from chrysene and triphenylene .
EFFL: Several waste water samples contaminated with possible industrial or bituminous waste
ranged from 25-10,360 ug/cu m . Industries with mean raw waste water concentrations >150
ppb: organic chemicals manufacturing/plastics (880 ppb), foundries and iron and steel
manufacturing; industries <100 ppb: photographic equipment/supplies, timber products
processing, electrical/electronic components, nonferrous metal manufacturing and coil coating .
Oslo, Norway - Bikkelaget sewage treatment plant effluent- dry period - 27 and 40 parts/trillion,
1979 and 1980 resp, after rainfall - 58 and 184 parts/trillion, 1979 and 1980 resp . Industrial
Kitakyushu area, Japan - sewage effluent - 53 ppb . Exhaust from 2-cycle diesel engine 2.3-15
ug/cu m . Emissions from representative European gasoline engine leaded and unleaded - 7.3 to
32.4 ppb; emissions from asphalt hot mixing plant 5 to 24 ng/cu m; coke oven emissions - 105 to
2740 ppm ; cigarette smoke 0.3 ug/100 cigarettes(3,5). Domestic effluent - 0.191 to 0.319
ppb . Sewage influent from Kitahyushu area Japan - 200 pbb . Sewage water from household,
trade, road, and industrial sources 31.4 ppb max .
|
|---|
