Fertilizers and plastics are poisoning the oceans, says UN

Posted: 17 February 2011

Massive amounts of phosphorus - a valuable fertilizer needed to feed a growing global population - are being lost to the oceans as result of inefficiencies in farming and a failure to recycle wastewater, according to a new UN report.

Phosphorus pollution, along with other uncontrolled discharges, such as nitrogen and sewage, are linked with a rise in algal blooms which in turn harm water quality, poison fish stocks and undermine coastal tourism.

Global sources of phosphorus fertilizer
Global sources of phosphorus fertilizer. Since the mid-1940s, population growth accompanied by greater food demand and urbanization have led to a dramatic increase in the use of mined phosphate rock compared with other sources of phosphorus. Source: Cordell et al. (2009)

In the United States alone, the costs are estimated to be running at over US$2 billion a year, indicating that globally and annually the damage may run into the tens of billion of dollars.

At the same time, says the UNEP 2011 Year Book, there is also growing concern over the impact of billions of pieces of plastic, both large and small, on the health of the global marine environment.

New research suggests that the plastic broken down in the oceans into small fragments -alongside pellets discharged by industry-may absorb a range of toxic chemicals linked to cancer and impacts the reproductive processes of humans and wildlife.

Experts say both phosphorus discharges and new concerns over plastics underline the need for better management of the world's wastes and improved patterns of consumption and production.

 Looking for solutions

The two issues are spotlighted in the new Year Book, which is being presented today in advance of the annual gathering of the world's environment ministers opening on 21 February.

Achim Steiner, UNEP Executive Director, said: "The phosphorus and marine plastics stories bring into sharp focus the urgent need to bridge scientific gaps" and make possible the global transition to a resource-efficient Green Economy. He said the ministers would work on a short-list of key scientific challenges that, acted upon, would help that  transition.

" Whether it is phosphorus, plastics or any one of the myriad of challenges facing the modern world, there are clearly inordinate opportunities to generate new kinds of employment and new kinds of more efficient industries," he added.

Limited reserves

The demand for phosphorous has rocketed during the past century, the Year Book says, and there is a heated debate on the when resources will run out. Some 35 countries produce phosphate rock  -- the top ten countires with the highest  reserves being Algeria, China, Israel, Jordan, Russia, South Africa, Syria and the United States.

New phosphate mines have been commissioned in countries such as Australia, Peru and Saudi Arabia and countries and companies are looking further afield, including on the seabed off the coast of Namibia.

Some researchers are suggesting that the consumption of phosphorus globally is in the medium to long term unsustainable and that peak production, with a decline afterwards, could occur in the 21st century.

Others disagree. The International Fertilizer Development Centre recently revised upwards estimates of reserves from around 16 billion tonnes to 60 billion tonnes-at current production rates, these could last 300 to 400 years. The Year Book calls for a global phosphorus assessment of viable reserves.

It says the global use of fertilizers that contain phosphorus, nitrogen and potassium increased by 600 per cent between 1950 and 2000. And it adds that population growth in developing countries and increased levels of dairy and meat in the global diet are likely to increase fertilizer use further.

Over the last 50 years concentrations of phosphorus in freshwaters and land has grown by at least 75 per cent.

The estimated flow of phosphorus to the marine environment from the land is now running at around 22 million tonnes a year. But there are enormous opportunities of recycling wastewater says the Year Book. In the mega-cities of the developing world up to 70 per cent of this water -- laden with nutrients and fertilizers such as phosphorus -- is discharged untreated into rivers and coastal areas.

Sweden, for example, aims to recycle 60 per cent of the phosphorus in municipal wastewater by 2015. Other measures to reduce discharges include cutting erosion and the loss of topsoil where large quantities of phosphorus are associated with soil particles and excess fertilizers that are stored after application. 
See also: Plastics: a new toxic time bomb?

The UNEP Year Book 2011 is available at www.unep.org/yearbook/2011