302 Resources from the Ocean Floor
10.5.6 Assessment of risk. Clearly, it is desirable to assess the potential impact of
dumping of hazardous materials before such dumping takes place. In any case, one
would hope that existing (if unfortunate) instances of hazardous dumping are used to
study the processes which determine the fate of the materials in question. These
include dispersion of the substances, and alteration through chemical reactions. Also,
the bio-activity is of vital importance (Fig. 10.15).
Dispersion is controlled by bioturbation, resuspension, and transport by currents,
which oppose the effects from natuml burial. Chemical reactions on and within the
sediment can change the toxicity of materials, and the ease with which they migrate
through the sediment, or are taken up by organisms. A well-known example with dire
consequences is the mobilization of mercury by methylation within anaerobic sediments. Methyl-mercury can end up in fish which then become poisonous, causing
"Minamata Disease", if consumed in sufficient quantitiy. The disease is named after
a bay in Japan where contamination offish occurred from release of mercury, leading
to much suffering and death.
An important aspect of the waste disposal problem is the scarcity of acceptable
dumping sites on land. One reason for this is the subjective desire of most communities to site dumps outside their own jurisdiction where possible, another is the
objective danger of groundwater contamination, which rules out many otherwise
suitable areas. Incineration (which can help heat a city) is rarely favored because of
its effects on air qUality. Thus, the price of dumping has risen sharply. This makes the
ocean attractive as a dumping ground.
Deep-sea dumping is a classic case of cost extemalization. The communities doing
the dumping reap the benefit of being rid of the noxious material which arose from
their activities, while the risk is spread evenly to all using the oceans, including - in
the case where the damage is irreversible - future generations.
One important task of marine geologists studying the sea floor - and perhaps the
most difficult yet - is to help assess the risks with which we burden the future.
Further Reading
Rona PA. Bostrom K. Laubier L. Smith KL (eds) (1983) Hydrothermal processes at sea floor
spreading centers. Plenum Press. New York
Tissot B. Welte DH (1984) Petroleum formation and occurrence. 2nd edn. Springer. Berlin New
York
Notholt AJG. Jarvis I (1990) Phosphorite research and development. Geol Soc Lond Spec Publ 22,
London
Cronan OS (1992) Marine mineral in exclusive economic zones. Chapman and Hall, London
Hsii KJ, Thiede J (eds) (1992) Use and misue of the seafloor. Dahlem Konferenzen. Wiley, New
York
10.5.6 Assessment of risk. Clearly, it is desirable to assess the potential impact of
dumping of hazardous materials before such dumping takes place. In any case, one
would hope that existing (if unfortunate) instances of hazardous dumping are used to
study the processes which determine the fate of the materials in question. These
include dispersion of the substances, and alteration through chemical reactions. Also,
the bio-activity is of vital importance (Fig. 10.15).
Dispersion is controlled by bioturbation, resuspension, and transport by currents,
which oppose the effects from natuml burial. Chemical reactions on and within the
sediment can change the toxicity of materials, and the ease with which they migrate
through the sediment, or are taken up by organisms. A well-known example with dire
consequences is the mobilization of mercury by methylation within anaerobic sediments. Methyl-mercury can end up in fish which then become poisonous, causing
"Minamata Disease", if consumed in sufficient quantitiy. The disease is named after
a bay in Japan where contamination offish occurred from release of mercury, leading
to much suffering and death.
An important aspect of the waste disposal problem is the scarcity of acceptable
dumping sites on land. One reason for this is the subjective desire of most communities to site dumps outside their own jurisdiction where possible, another is the
objective danger of groundwater contamination, which rules out many otherwise
suitable areas. Incineration (which can help heat a city) is rarely favored because of
its effects on air qUality. Thus, the price of dumping has risen sharply. This makes the
ocean attractive as a dumping ground.
Deep-sea dumping is a classic case of cost extemalization. The communities doing
the dumping reap the benefit of being rid of the noxious material which arose from
their activities, while the risk is spread evenly to all using the oceans, including - in
the case where the damage is irreversible - future generations.
One important task of marine geologists studying the sea floor - and perhaps the
most difficult yet - is to help assess the risks with which we burden the future.
Further Reading
Rona PA. Bostrom K. Laubier L. Smith KL (eds) (1983) Hydrothermal processes at sea floor
spreading centers. Plenum Press. New York
Tissot B. Welte DH (1984) Petroleum formation and occurrence. 2nd edn. Springer. Berlin New
York
Notholt AJG. Jarvis I (1990) Phosphorite research and development. Geol Soc Lond Spec Publ 22,
London
Cronan OS (1992) Marine mineral in exclusive economic zones. Chapman and Hall, London
Hsii KJ, Thiede J (eds) (1992) Use and misue of the seafloor. Dahlem Konferenzen. Wiley, New
York