This is a problem affecting every coastline around the world – but particularly where there is a large population off the coast and an industrialized lifestyle.
THE MARINE degradation happening of Sydney’s coastline makes eating seafood caught in Sydney waters a health hazard. This has happened because the Water Board has sought to supply industry with a cheap waste disposal system, because the SPCC has failed to set standards that would properly implement the Clean Waters Regulations, and because politicians of both major parties have cooperated in a decade or more of cover-ups, keeping secret the evidence that toxic waste has been accumulating in fish to an alarming extent.
Sharon Beder has written the book Toxic Fish and Sewer Surfing, from which this article was gleaned. Thank you for your work Ms Beder.
Industrial waste going to the sea via the sewers poses a major threat both to the marine environment and to the health of people who eat fish. Organic chemicals such as those in the organochlorine group are very stable and often persist in the environment for long periods. Fish can accumulate these compounds even when there are very 1ow concentrations in the water. The toxins can be concentrated as each organism is in turn eaten by another.
Other toxic materials, like trace metals, can also be absorbed from the water or eaten in contaminated food or aquatic plants. Of the heavy metals that are discharged in industrial waste, mercury and cadmium are of particular concern because of well-documented acute health effects. In Minamata, Japan, more than 100 people died and 700 suffered ‘severe, permanent neurological damage’ after eating seafood that had been contaminated by industrial waste containing mercury. Also in Japan, 60 people died when rice paddies were contaminated with industrial waste containing cadmium. Other heavy metals also pose a health threat if they are present in human food.
Often the level which is considered safe for human consumption purposes is higher than the level considered safe for protection of fish and birds.
In 1987 a United States Office of Technology Assessment Report argued that ‘a strong overall case can be established that waste disposal activities are contributing significantly to substantial declines in the quality of marine waters and harming marine organisms’. The report noted that some organisms are more vulnerable than others, especially bottom-dwelling organisms and those which spend all or part of their lives in coastal waters, as well as those that inhabit polluted waters during sensitive parts of their life cycles. Also marine birds and mammals which are at the top of the food chain can suffer because of the accumulation of pollutants which can lead to impaired reproduction in the animals. For example, in California, the decline of the brown pelican population and that of several other bird species has been directly linked to DDT-contaminated fish.
Actual deaths of organisms due to pollution are difficult to detect, unless there is a mass killing that causes fish to be washed up in numbers on a beach or shore, because very sick or dead organisms don’t last very long. Nevertheless, other symptoms such as behavioural and physiological effects, as well as changes in abundance and distribution of organisms and fish, have been detected in various polluted coastal waters in the United States and the US Office of Technology Assessment report states that:
a growing body of evidence links these effects to exposure to pollutants that sometimes are present at very low concentrations or to environmental changes induced by pollutants . . . The effects are concentrated in estuaries and coastal waters, but detectable effects also have been found in fish far from shore in the open ocean . . . considerable circumstantial evidence indicates that pollutants from waste disposal activities have contributed to declines of major fish populations in the United States.
Noticeable physiological effects include fin erosion (fin rot), ulcers, shell disease or erosion, tumours and skeletal anomalies. Resistance to infection, growth and reproductive ability can also be affected and although these effects may not be immediately fatal they can lead to a premature death. More- over, submerged aquatic vegetation, which is an important part of the ecosystem that not only provides shelter and food but also sediment-stabilising functions, seems to have been generally decreasing in the United States coastal areas and bottom-dwelling communities ‘have been affected by waste disposal in every region of the country’.
Book: Toxic Fish and Sewer Surfing