Large amounts of phosphorus, a crucial fertilizer, are discharged into oceans as result of inefficiencies in farming and a failure to recycle wastewater, the United Nations Environment Programme (UNEP) says in its 2011 Year Book released Thursday, which also voices concern over plastics pollution.

Fish at sea [File photo]

Experts cited in the Year Book, released ahead of the annual gathering of the world's environment ministers that opens on Monday, says that both phosphorus discharge and new concerns over plastics underline the need for better management of the world's wastes and improved patterns of consumption and production.

"The phosphorus and marine plastics stories bring into sharp focus the urgent need to bridge scientific gaps but also to catalyze a global transition to a resource-efficient Green Economy in order to realize sustainable development and address poverty," said Achim Steiner, the UNEP Executive Director.

"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.

The UNEP Year Book 2011 has highlighted phosphorus, demand for which has rocketed during the 20th century, in part because of the heated debate over whether or not finite reserves of phosphate rock will soon run out.

An estimated 35 countries produce phosphate rock with the top ten countries having 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.

The Year Book calls for a global phosphorus assessment to more precisely map phosphorus flows in the environment and predict levels of economically viable reserves.

"While there are commercially exploitable amounts of phosphate rock in several countries, those with no domestic reserves could be particularly vulnerable in the case of global shortfalls," the Year Book notes.

Further research is also needed on the way phosphorus travels through the environment to maximize its use in agriculture and livestock production and cut waste while reducing environmental impacts including on rivers and oceans, according to the Year Book.

It also points to the enormous opportunity of recycling wastewater. Up to 70 per cent of this water is laden with nutrients and fertilizers such as phosphorus, which is discharged untreated into rivers and coastal areas.

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 are stored after application.

The Year Book highlights a new and emerging concern termed "persistent, bio-accumulating and toxic substances" associated with plastic marine waste.

Research indicates that small and tiny pieces of plastic are adsorbing and concentrating from the seawater and sediments a wide range of chemicals from polychlorinated biphenols (PCBs) to the pesticide DDT.

"Many of these pollutants including PCBs cause chronic effects such as endocrine disruption, mutagenicity and carcinogenicity," according to the Year Book.