sewage treatment plant ----';:'+--,---,---. ....
.37
.74
.46
.459
.376
.166
.222
.200
.264
1 km
Fig. 43. The distribution of benzo(a)pyrene in the sediment along the
coast of Vancouver, British Columbia,
Canada, indicates that the introduction of waste water plays a role.
The Iona Island treatment plant processes 320,000 m 3 of effluents per
day. In J-lg/kg, the data indicate how
much benzo(a)pyrene the organic
matter in the sediment contains
(Dunn and Stich 1976)
(England) concentrations of up to 0.5 mg/kg have been found in the sediment
(Thompson and Eglington 1978). In such situations, a monitoring of shellfish could
be necessary, but the reason for the high contamination does not seem to be petroleum.
5.3 Sources of Marine Pollution by Petroleum
After public opinion was aroused in 1970 by the news that 5-10 million t of petroleum pollute the world's oceans per year, the estimated amounts were recalculated
for recent years. But because it obviously is not easy to get hold of the exact amounts,
there are still considerable gaps between the various estimates (Table 14).
In 1971, 2500 million t of petroleum were transported all over the world 2 . Of this
amount, 400 million t came from off-shore wells; 1400 million t were shipped to
their destination by 6000 tankers. In 30 years, the amount has increased more than
tenfold. This explaines why oil pollution has hardly decreased despite the many
attempts to reduce it.
Because they are said to contribute only 0.3 million t per year to ocean pollution,
accidents play only a minor role. However, when there is a tanker accident, the damage
is particularly obvious, and the public is justifiable interested in it. However, other
sources of oil pollution deliver much larger amounts of oil to the sea.
It must be emphasized that there are coastal areas where off-shore oil deposits are so
close to the bottom of the ocean that crude oil escapes and fouls the water and the
ocean surface. As far as the overall picture is concerned, just as much petroleum
reaches ocean water from such natural undersea oil seeps as through accidents.
2 1 t of petroleum corresponds to about 1.16 m 3 or 7.3 barrels, because 1 m 3 contains 6.3 barrels with each 42 US gallons
80
.37
.74
.46
.459
.376
.166
.222
.200
.264
1 km
Fig. 43. The distribution of benzo(a)pyrene in the sediment along the
coast of Vancouver, British Columbia,
Canada, indicates that the introduction of waste water plays a role.
The Iona Island treatment plant processes 320,000 m 3 of effluents per
day. In J-lg/kg, the data indicate how
much benzo(a)pyrene the organic
matter in the sediment contains
(Dunn and Stich 1976)
(England) concentrations of up to 0.5 mg/kg have been found in the sediment
(Thompson and Eglington 1978). In such situations, a monitoring of shellfish could
be necessary, but the reason for the high contamination does not seem to be petroleum.
5.3 Sources of Marine Pollution by Petroleum
After public opinion was aroused in 1970 by the news that 5-10 million t of petroleum pollute the world's oceans per year, the estimated amounts were recalculated
for recent years. But because it obviously is not easy to get hold of the exact amounts,
there are still considerable gaps between the various estimates (Table 14).
In 1971, 2500 million t of petroleum were transported all over the world 2 . Of this
amount, 400 million t came from off-shore wells; 1400 million t were shipped to
their destination by 6000 tankers. In 30 years, the amount has increased more than
tenfold. This explaines why oil pollution has hardly decreased despite the many
attempts to reduce it.
Because they are said to contribute only 0.3 million t per year to ocean pollution,
accidents play only a minor role. However, when there is a tanker accident, the damage
is particularly obvious, and the public is justifiable interested in it. However, other
sources of oil pollution deliver much larger amounts of oil to the sea.
It must be emphasized that there are coastal areas where off-shore oil deposits are so
close to the bottom of the ocean that crude oil escapes and fouls the water and the
ocean surface. As far as the overall picture is concerned, just as much petroleum
reaches ocean water from such natural undersea oil seeps as through accidents.
2 1 t of petroleum corresponds to about 1.16 m 3 or 7.3 barrels, because 1 m 3 contains 6.3 barrels with each 42 US gallons
80