Report warns of rising tide of sewage

A rising tide of sewage is threatening the health of humans and wildlife living in and around many of the world's seas and oceans, according to a report by the United Nations environment programme (UNEP) released today.

In many developing countries, it is estimated that between 80% and 90% of sewage entering coastal zones is raw and untreated, the state of the marine environment report says.

This is putting at risk marine wildlife, the health of the local population and industries including fishing and tourism.

The reasons for the rise in sewage pollution are inadequate treatment infrastructure and waste handling facilities together with rising coastal populations, the report says. Almost 40% of the world's population live on the fringes of the coast, although this area covers just 7% of the land.

UNEP says it would cost an estimated $56bn (£30bn) a year more to address the waste water problem, suggesting countries could ask the biggest polluters to help fund the work.

"In the past we thought the ocean could be our sewage treatment plant," UNEP's executive director, Achim Steiner, told a news conference in The Hague.

"This sewage is not just something that goes into the sea and the sea does it for us anymore."

The report says progress has been made in reducing oil pollution and the discharge of toxic waste into the world's oceans, but the problems of litter and pollution by nutrients from the land are getting worse.

The number of coastal "dead zones" has doubled every decade since 1960, with the rise linked to an increased presence of nitrogen and phosphorus, it says.

These nutrients, which come from agricultural fertilisers running off the land, from manure, sewage and fossil fuels, have led to "over-enrichment" in some areas, which can lead to the death of wild and farmed fish, and endanger seagrass beds and coral reefs.

Nitrogen leaching into the marine environment from rivers is expected to rise globally by 14% by 2030 when compared with the mid 1990s.

The problem was once largely confined to developed countries but is now spreading to developing nations, the report says, with rivers running through Cambodia, China, Malaysia, Thailand and Vietnam now delivering nitrogen to the waters above the Sunda Shelf.

"An estimated 80% of marine pollution originates from the land, and this could rise significantly by 2050 if, as expected, coastal populations double in just over 40 years' time and action to combat pollution is not accelerated," Mr Steiner said.

He added: "We have a long way to go politically, technically and financially if we are to hand over healthy and productive seas and oceans to the next generation."

The report's findings will be presented at a meeting in Beijing between October 16-20, which will review the progress of a global plan to protect oceans from land-based activities.

Chernobyl

 

The accident at the Chernobyl nuclear power station in the Ukraine on 26 April 1986, has been described as the worst-ever disaster in the world. A sequence of operational errors resulted in an explosion that blew the roof off reactor No. 4, hurling radioactive debris into the air, and starting an enormous fire. Radioactive clouds trailed from the stricken plant, polluting more than 20 countries up to 2,000 km away. It is difficult to project the number of deaths from the accident, as estimates vary from a few thousand to hundreds of thousands of people: what can be said with certainty is that Chernobyl-related deaths will continue to occur for the next 50 years. In September 1986, the USSR calculated the cost of the disaster to the Soviet economy at £2 billion: by 1988, the projected cost had increased to £14 billion. The eventual total cost over the years may be as high as £200 billion       

  The Chernobyl plant was one of the best in the country, with efficient operational staff. It contained safety features not found in certain Western installations, including substantial steel and concrete containment walls round the reactor; modern control equipment, including sensors and measuring equipment made in West Germany.

According to the detailed analysis presented by the USSR to the International Atomic Energy Authority in August 1986, human error was largely responsible for the Chernobyl accident.

There were immediate casualties. In two days about 300 patients were sent to Moscow hospitals. Doctors had to divide the patients into three groups: those who were going to die, those who might live with treatment, and those who did not need immediate care. The middle group received priority attention, but surgeons needed to operate cautiously, as the affected people had absorbed so much radiation that internal organs, blood and urine had become radioactive. Within 10 days 130,000 people were evacuated.

At the plant itself, the first task was to stop the fire spreading to the other units. This was achieved by extraordinary heroism on the part of Soviet firefighters, working in the areas which they knew to be radioactive. Many died as a result. More will perish from the long-term effects of radiation exposure. Only on the10th day, the radioactive release was stopped.

Scientists predicted that during the next 50 years there would be up to 60,000 extra cancer-related deaths, 1,000 birth defects and 5,000 cases of genetic abnormality as a result of the Chernobyl accident, with about 40 per cent of the deaths occurring in the USSR. Other contaminated European countries would also suffer.

Specialists agree that another Chernobyl-type disaster is unavoidable while present technology is operated by humans. Every reactor design has advantages and disadvantages compared to the others. The lesson of Chernobyl is that all nuclear reactors contain within themselves the capacity for enormous environmental disaster.  

Wonders of the waste land

Part rubbish heap, part sewage works, the wetlands of Kolkata are among the world's great eco-systems, says Tony Juniper.

The overpowering stench of human waste hangs heavily on the humid air. In the 37C heat preceding the imminent monsoon, it is almost suffocating. But the smell is not surprising when you know that the wetlands to the east of Kolkata, or Calcutta as the teeming metropolis used to be known, receive some 680m litres of raw sewage every day. Amazingly, the wetlands' mosaic of ponds, lakes, channels and swamps are the only sewage treatment facilities the 12 million or so inhabitants of the city have.

And that's not all: the wetlands are also the destination for more than 3,000 tonnes of municipal waste produced in Kolkata each day. Despite being a sink for the less pleasant products of a vast city, the wetlands are also important for conservation. An impressive range of migrant and -resident birds and animals can be spotted there, including the endemic marsh mongoose.

Perhaps surprisingly, given they are in part rubbish dump and sewage works, the east Kolkata wetlands are listed under wetlands of international importance by the Ramsar Convention. This is not solely because of their wildlife value; primarily it is because the ecosystem supports diverse human activities, and therefore - theoretically - could advance the convention's objective of promoting sustainable use of wetlands - as well as their protection.

Use of the wetlands is intense. The roads that bring visitors from Kolkata pass through the areas where the city's waste is dumped. It is sorted by bands of so-called rag pickers. People existing on the margins of society process the waste into neat piles of translucent polythene, sparkly piles of aluminium foil fragments, mounds of glass, scrap metals and, the real prize, compost.

The work is filthy and dangerous. Broken glass and clinical waste are mixed in with the unsorted waste. The pickers, including young children, have no protective clothing, not even gloves. Under these dreadful conditions, the pickers manage to scratch a living. Sorted materials are sold for recycling, while the compost is spread on plots of land that produce a variety of vegetables.

Adjacent to the little vegetable plots, sewage arrives from the city along slow flowing channels. As the solids separate out, the ponds are dredged and the black solids spread on to the small fields and garden plots that intersperse the wet areas. This material, along with the compost and irrigation from the waste water, helps the people who live and work on the wetlands to produce tonnes of vegetables.

Once solids are dredged out, the liquid fraction is passed to pools filled with fast-growing water hyacinths. These tough but rather at tractive plants not only accumulate biomass but absorb some of the heavy metals and other toxins released from small-scale industries, such as tanneries.

When the organic pollution in the water is partly diminished by the plants, it is used to top up fish ponds. All across the wetlands there is fish rearing - and on a grand scale. About a dozen species of freshwater fish are raised, in more than 300 ponds covering about 35 square kilometres. Between them, they produce a staggering 13,000 tonnes of fish a year, much of it consumed in Kolkata.

Some 50,000 people depend on the wetlands for their living: growing vegetables, trading and making nets, or maintaining the channels. The fish rearing alone supports a workforce of about 8,000 people. Many also rear pigs and ducks. The pigs run semi-wild and eat whatever they can find. The ducks are fattened with aquatic snails harvested from the ponds.

Sustaining this unique system should be a priority for policy makers, and researchers, including a group from the University of Stirling in Scotland, are embarked on that process. If the lives of the people and the economy of this place can be better understood, then perhaps their welfare can be improved, alongside moves toward long-term sustainable management. The alternative is the development of the wetlands for ur ban expansion, that would, in turn, lead to a loss of food for the city and necessitate the construction of expensive sewage works.

There are problems. The expansion of Kolkata and the ever present pressure of development is thought by some to be the reason why no official boundary map of the Ramsar-listed area has been published. The government of West Bengal, it is thought, is hedging its bets on where development will go before committing to a legally binding boundary.

Siltation is a growing problem as well, with many of the fish ponds gradually filling up. If the wetlands are to survive, then large-scale dredging will be needed. And as the city grows ever larger, so the volume of sewage and waste grows, too. How long the wetlands can accommodate that growth is not known.

One of the few new commitments made by governments at the 2002 Johannesburg summit on sustainable development was to improve access to sanitation. However, if there is really a context of sustainable development in which that aim will be pursued then not only should there be an emphasis on concrete, pipes and electricity but also an appreciation of the central role that can be played by people, habitats and farming.