Rising tide of sewage threatens world’s oceans, endangering human health, wildlife – UN

While good progress has been made in curbing oil and chemical pollution, a rising tide of sewage is threatening the world’s seas and oceans, endangering human health, wildlife and livelihoods ranging from fisheries to tourism, according to a new United Nations report published today.

“An estimated 80 per cent 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,” UN Environment Programme (UNEP) Executive Director Achim Steiner warned.

“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,” he said, with $56 billion needed annually just to address the waste water problem.

Compounded by rising coastal populations, inadequate treatment infrastructure and waste handling facilities, up to nearly 90 per cent of sewage entering coastal zones in many developing countries is estimated to be raw and untreated, according to the UNEP study, the State of the Marine Environment report.

Beyond the direct health and economic impact on health and livelihoods, the report underscores rising concern over the increasing destruction of essential and economically important coastal ecosystems like mangrove forests, coral reefs and sea-grass beds.

On the positive side, it notes that levels of oily wastes discharged from industry and cities has been cut globally by close to 90 per cent since the mid 1980s, and other successes are being scored in curbing marine contamination from toxic persistent organic pollutants like DDT and discharges of radioactive wastes, though there are still areas of concern in the Caspian and western Mediterranean seas and the Arctic and South Pacific oceans.

The report says overall good progress is being made on three of nine key indicators, is mixed for two and is heading in the wrong direction for a further four, including sewage, marine litter and “nutrient” pollution from sources like agriculture and animal wastes that fertilize coastal zones, triggering toxic algal blooms and a rising number of oxygen deficient ‘dead zones.’

It also flags up fresh areas in need of urgent attention such as the declining flows in many of the world’s rivers as a result of dams, over-abstraction and global warming; new streams of chemicals; the state of coastal and freshwater wetlands and sea-level rise linked with climate change.

It calls for improved monitoring and data collection on continents like Africa where the level of hard facts and figures on marine pollution remains fragmented and woefully low.

Highlighting the four areas of most concern, the report notes:

• Sewage – discharge of untreated wastewater ranges from over half of that entering the Mediterranean and 60 per cent in the Caspian Sea to 80 per cent in West and Central Africa and the South-East Pacific, 85 per cent in Latin America and the Caribbean and 90 per cent in East Asia.
• Nutrients - the number of coastal dead zones has doubled every decade since 1960 with the rise linked to nitrogen and phosphorus from agricultural fertilizer run off, manure, sewage and fossil fuel burning; the problem, once largely confined to developed countries, is now spreading to developing ones.
• Marine Litter - sources include municipal, industrial and medical discharges as well as that from fishing boats and other shipping discharges, threatening health and wildlife, and much of it not bio-degradable.
• Physical Alteration and Destruction of Habitats – with some 40 per cent of the world’s population living on just the costal fringe (just over 7 per cent of all land) and population density there set to rise from 77 people per square kilometre in 1990 to 115 in 2025, ecosystems are being lost, marine resources overused and pollution compounded.