Antifouling paints which use tin or copper as toxicants, the latter mostly as copperoxyde, or more modern types of organometallic compounds are legal. Chromium,
lead, and zinc are important constituents of bottom primers, cadmium is used in
some paints, and zinc in sacrificial anodes to prevent steel hulls from corrosion. At
the coast of southern California, U.S.A., between Santa Barbara and San Diego,
37,500 recreational boats are moored, and their bottom is painted annually with a
paint that contains, on the average, 600 g of copper per liter. That amounts to 180 t
of copper which are used annully and which in some way enter the environment,
mostly the marine environment. The figure is significant compared with copper input
into the area with municipal outfall of the Los Angeles region (510 t), with surface
runoff (40 t) and with dry aerial outfall (30 t). Copper from boats and ships, therefore, is the reason for elevated copper concentrations for example in the mussel,
Mytilus edulis. In Newport Harbor, with a high concentration of recreational boats
and repair yards, copper in mussel muscle is about nine times higher than in mussels
from the open shore, and values for cadmium, chromium, lead, tin, and zinc are also
elevated (Young et al. 1979).
It may be that the more modern types of hard antifouling are effective with less
quantities of heavy metals and therefore do not contaminate the marine environment
to such an extent; however, detailed investigations are lacking, and at least in the
Federal Republic of Germany one obtains no information about the heavy metal
concentrations of the content, if one buys a tin of antifouling.
4.5 Garbage from Ships
The wealthy countries of the world produce, exclusive of kitchen leftovers, 1.6 kg
of garbage per capita per day. There are human beings on passenger ships on the
world's oceans for 17 million per capita days, and they produce 28,000 t of garbage
per annum. Merchant marine crews are said to produce 0.8 kg of garbage per day
which consists of 63% paper, 15% metal, 10% textiles, 10% glass, and 1 % plastic and
rubber. On the average, there are 9000 large merchant marine vessels on the seas.
With a 40-man crew, this means 140 million per capita days and 110,000 t of garbage
per annum. For the 3 million pleasure craft, 103,000 t of garbage are estimated,
340,000 t for the 120,000 fishing vessels, and 74,000 t of garbage for navy vessels.
If the waste residue thrown overboard from a ship's load, and sunken vessels from
accidents on the high seas are added to these figures, we arrive at an estimated figure
of approximately 6 million t of refuse annually stemming from navigation for all the
oceans of the world (National Academy of Science 1975a).
Naturally, coastal areas are the ones that are primarily affected. Part of the garbage
decomposes, part of it sinks to the bottom of the ocean. Some refuse, however,
floats on the surface of the ocean for a long period of time until washed up on a
beach. For this reason, ongoing national and international efforts are underway to
prohibit ships from throwing garbage overboard (see Chap. 10). It is good to know
that since 1980 the Helsinki Convention forbids even small vessels to throw garbage
overboard in the Baltic Sea.
69
lead, and zinc are important constituents of bottom primers, cadmium is used in
some paints, and zinc in sacrificial anodes to prevent steel hulls from corrosion. At
the coast of southern California, U.S.A., between Santa Barbara and San Diego,
37,500 recreational boats are moored, and their bottom is painted annually with a
paint that contains, on the average, 600 g of copper per liter. That amounts to 180 t
of copper which are used annully and which in some way enter the environment,
mostly the marine environment. The figure is significant compared with copper input
into the area with municipal outfall of the Los Angeles region (510 t), with surface
runoff (40 t) and with dry aerial outfall (30 t). Copper from boats and ships, therefore, is the reason for elevated copper concentrations for example in the mussel,
Mytilus edulis. In Newport Harbor, with a high concentration of recreational boats
and repair yards, copper in mussel muscle is about nine times higher than in mussels
from the open shore, and values for cadmium, chromium, lead, tin, and zinc are also
elevated (Young et al. 1979).
It may be that the more modern types of hard antifouling are effective with less
quantities of heavy metals and therefore do not contaminate the marine environment
to such an extent; however, detailed investigations are lacking, and at least in the
Federal Republic of Germany one obtains no information about the heavy metal
concentrations of the content, if one buys a tin of antifouling.
4.5 Garbage from Ships
The wealthy countries of the world produce, exclusive of kitchen leftovers, 1.6 kg
of garbage per capita per day. There are human beings on passenger ships on the
world's oceans for 17 million per capita days, and they produce 28,000 t of garbage
per annum. Merchant marine crews are said to produce 0.8 kg of garbage per day
which consists of 63% paper, 15% metal, 10% textiles, 10% glass, and 1 % plastic and
rubber. On the average, there are 9000 large merchant marine vessels on the seas.
With a 40-man crew, this means 140 million per capita days and 110,000 t of garbage
per annum. For the 3 million pleasure craft, 103,000 t of garbage are estimated,
340,000 t for the 120,000 fishing vessels, and 74,000 t of garbage for navy vessels.
If the waste residue thrown overboard from a ship's load, and sunken vessels from
accidents on the high seas are added to these figures, we arrive at an estimated figure
of approximately 6 million t of refuse annually stemming from navigation for all the
oceans of the world (National Academy of Science 1975a).
Naturally, coastal areas are the ones that are primarily affected. Part of the garbage
decomposes, part of it sinks to the bottom of the ocean. Some refuse, however,
floats on the surface of the ocean for a long period of time until washed up on a
beach. For this reason, ongoing national and international efforts are underway to
prohibit ships from throwing garbage overboard (see Chap. 10). It is good to know
that since 1980 the Helsinki Convention forbids even small vessels to throw garbage
overboard in the Baltic Sea.
69