298 Resources from the Ocean Roor
10.5 Waste Disposal and Pollution
10.5.1 A Change in Pace. Man's impact on the marine environment spans a wide
range of interference with natural processes. One of the oldest, one may assume, is
the increased delivery of sediments to estuaries and harbors caused by increased
erosion on land from working the soil, and from deforestation. Basically, this should
accelerate the filling-in of estuaries and affected lagoons. Conversely, the building of
large dams upriver has led to interception of sediments, and the starvation of beaches,
which promotes the erosion of the coastline. For example, since the construction of
the Aswan High Dam in 1964 in the uplands of Egypt, shoreward erosion around the
Nile delta region has increased to annually over 150 m near headlands.
Coastal cities have contributed nutrients for algal growth along their shores for
centuries, and this process has continued and accelerated with population growth. In
places where waste amounts are sufficiently large and water bodies restricted, bays
are fouled, and sensitive ecosystems (such as coral reefs) are damaged.
What is new in our time is a massive increase of waste off rapidly growing cities,
with unhealthy environmental effects well away from the sources of pollution. Such
effects may include dangerous levels of pathogenic bacteria, and bursts of growth
("blooms") of noxious dinoflagellates. Also new is the production of potent and
long-lived industrial poisons which are effective at low concentrations. One prime
example is the accumulation of pesticides in certain seabirds, through the food-chain
effect, which can wreak havoc with their reproductive success. Oil spills and the
introduction of radioactive materials likewise are modem developments, as is the
large-scale addition of chemical-industrial waste.
Because of the economic interests involved, the study of problems connected with
disposal and pollution has become an important subject in environmental marine
geology, and it is a field that is likely to grow. Studies involve the cooperation of
many scientists (e. g., chemists and biologists), commonly from different countries,
as pollution crosses boundaries. How can we monitor environmental changes and
detect possible causes? A promising method is biological monitoring (Fig. 10.14).
The observed changes set a warning signal, but it is commonly difficult to define the
- natural or anthropogenic - factors responsible for the changes.
10.5.2 Sewage and Sludge. Industrial man uses energy and raw materials and produces waste. Most of the waste, such as sewage sludge, is relatively innocuous
provided it is without potent poisons (certain metals, for example, or biocides). Of
course, the amounts introduced must not exceed what the ocean can absorb by dilution and bacterial action (which makes estuaries more vulnerable than open ocean
sites). Under these conditions sludge mainly acts as fertilizer.
When dumping of sludge proceeds on a grand scale in a limited area, problems
arise. For example, several years ago foul bottom conditions were reported from shelf
areas off New York in regions of dumping, as well as diseased benthic organisms.
Fishing activities, especially lobster fishing, are adversely affected under such circumstances. This has led to restrictions on dumping of sludge close to the coast, or
on the shelf; but even "deep" dumping can cause problems. Disposal of municipal
10.5 Waste Disposal and Pollution
10.5.1 A Change in Pace. Man's impact on the marine environment spans a wide
range of interference with natural processes. One of the oldest, one may assume, is
the increased delivery of sediments to estuaries and harbors caused by increased
erosion on land from working the soil, and from deforestation. Basically, this should
accelerate the filling-in of estuaries and affected lagoons. Conversely, the building of
large dams upriver has led to interception of sediments, and the starvation of beaches,
which promotes the erosion of the coastline. For example, since the construction of
the Aswan High Dam in 1964 in the uplands of Egypt, shoreward erosion around the
Nile delta region has increased to annually over 150 m near headlands.
Coastal cities have contributed nutrients for algal growth along their shores for
centuries, and this process has continued and accelerated with population growth. In
places where waste amounts are sufficiently large and water bodies restricted, bays
are fouled, and sensitive ecosystems (such as coral reefs) are damaged.
What is new in our time is a massive increase of waste off rapidly growing cities,
with unhealthy environmental effects well away from the sources of pollution. Such
effects may include dangerous levels of pathogenic bacteria, and bursts of growth
("blooms") of noxious dinoflagellates. Also new is the production of potent and
long-lived industrial poisons which are effective at low concentrations. One prime
example is the accumulation of pesticides in certain seabirds, through the food-chain
effect, which can wreak havoc with their reproductive success. Oil spills and the
introduction of radioactive materials likewise are modem developments, as is the
large-scale addition of chemical-industrial waste.
Because of the economic interests involved, the study of problems connected with
disposal and pollution has become an important subject in environmental marine
geology, and it is a field that is likely to grow. Studies involve the cooperation of
many scientists (e. g., chemists and biologists), commonly from different countries,
as pollution crosses boundaries. How can we monitor environmental changes and
detect possible causes? A promising method is biological monitoring (Fig. 10.14).
The observed changes set a warning signal, but it is commonly difficult to define the
- natural or anthropogenic - factors responsible for the changes.
10.5.2 Sewage and Sludge. Industrial man uses energy and raw materials and produces waste. Most of the waste, such as sewage sludge, is relatively innocuous
provided it is without potent poisons (certain metals, for example, or biocides). Of
course, the amounts introduced must not exceed what the ocean can absorb by dilution and bacterial action (which makes estuaries more vulnerable than open ocean
sites). Under these conditions sludge mainly acts as fertilizer.
When dumping of sludge proceeds on a grand scale in a limited area, problems
arise. For example, several years ago foul bottom conditions were reported from shelf
areas off New York in regions of dumping, as well as diseased benthic organisms.
Fishing activities, especially lobster fishing, are adversely affected under such circumstances. This has led to restrictions on dumping of sludge close to the coast, or
on the shelf; but even "deep" dumping can cause problems. Disposal of municipal