UN scientists report massive 'dead zones'

Rising tides of untreated sewage and plastic debris are seriously threatening marine life and habitat around the globe, the United Nations Environment Program (UNEP) warned in a report on Oct. 4. The number of ocean "dead zones" has grown from 150 in 2004 to about 200 today, said Nick Nuttall, a UNEP spokesperson. "These are becoming more common in developing countries," said Nuttall in Nairobi, Kenya. Dead zones can encompass areas of ocean up to 62,000 square miles in size where little can live because there is no oxygen left in the water. Nitrogen pollution, mainly from farm fertilizers and sewage, produces blooms of algae that absorb all of the oxygen in the water. Growing global populations, mainly concentrated along coastlines, and the resulting increase in untreated sewage are endangering human health and wildlife, as well as livelihoods from fisheries to tourism, according to the "State of the Marine Environment" report. "An estimated 80 percent of marine pollution originates from the land," said Achim Steiner, United Nations undersecretary-general and UNEP's executive director. "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," Steiner said in a statement. The report is compiled from a wide variety of government, academic and other sources by UNEP's Global Program of Action for the Protection of the Marine Environment from Land-Based Sources. In many developing countries, between 80 percent and nearly 90 percent of sewage entering the coastal zones is estimated to be raw and untreated. Some cities in the developed world also dump their sewage directly into waterways. More than one half of wastewater entering the Mediterranean Sea is untreated, as is 60 percent of the wastewater discharged into the Caspian Sea, the UNEP report found. Unlike the United States and countries in the European Union, Canada has no national standards for sewage treatment for cities. Montreal dumps billions of gallons of untreated sewage into the St. Lawrence River, while the postcard-perfect tourist city of Victoria, British Columbia dumps all of its waste directly into the Pacific Ocean. These wastes contain bacteria and viruses that can contaminate marine species and such waste can contain high levels of toxic chemicals, heavy metals and excreted pharmaceuticals. The latter pose risks that are only beginning to be understood. Emerging research shows negative impacts on marine life from residues of birth control and antidepressant drugs like Prozac even at extremely low concentrations. "The big unknown" is what effect these pharmaceutical residues might have on chronically exposed plants, animals and people, Christian Daughton, chief of the environmental chemistry branch at the US Environmental Protection Agency, has been reported as saying. Expensive treatment plants are not the only solution to untreated sewages wastes–coastal wetlands, salt marshes and mangroves can also do the job, Nuttall explained. "It's important for governments to conserve and rehabilitate these natural features and take their value into consideration in their urban planning," he said. Plastic is an even more visible environmental concern, killing more than a million seabirds and 100,000 mammals and sea turtles each year, according to previous UN reports. Plastic bags, bottle tops and polystyrene foam coffee cups are often found in the stomachs of dead sea lions, dolphins, sea turtles and birds. Seagulls in the North Sea had an average of 30 pieces of plastic in their bodies. Most plastics do not biodegrade, they just break up into ever-smaller particles. British scientists have discovered that microscopic pieces of plastic can be found everywhere in the oceans, even inside plankton, the foundation of the marine food chain. "The problem of marine litter has steadily grown worse, despite national and international efforts to control it," acknowledges the UNEP report. The report's findings will be officially presented to governments attending a review of the decade-old Global Program of Action initiative taking place in Beijing, China, from Oct. 16-20. There have been some improvements, the report notes. Levels of oily waste discharged from industry and cities has, since the mid 1980s, been cut by close to 90 percent. Marine contamination from toxic persistent organic pollutants like DDT and discharges of radioactive waste has also been sharply reduced.