Plastic Peril

Waste management is key to keeping the oceans free of plastic waste, new research suggests

The ocean is the final receptacle of a substantial amount of waste generated on land. Plastic pollution in the ocean was first reported in the scientific literature of the early 1970s. In just four decades, it has become a pressing environmental problem and has been found even in the most remote corners of the earth. The amount of plastic entering the oceans is up to 2,000 times more than earlier estimates.

A study published in the February 13, 2015 issue of the journal, Science, estimated the amount of plastic that could enter the oceans based on the amount of unmanaged waste. The researchers found that anything between 4.8 and 12.7 million tonnes (MT) of plastic enters the oceans each year (see ‘More data collection needed’).

The researchers estimated the quantity of plastic entering the oceans by using 2010 data on solid waste produced, population density and economic status of 192 countries that have a coastline. They found that 275 MT of plastic waste was generated in these countries. They then used a model to estimate the amount of plastic that is likely to enter the oceans every year, depending on the country’s ability to manage waste. The team found that the top 20 countries accounted for 83 per cent of the mismanaged plastic waste entering the ocean. China tops the list and throws 1.32 MT to 3.53 MT of plastic waste in the sea. India is 12th, contributing 0.09 MT to 0.24 MT plastic waste to oceans every year. America is 20th, throwing 0.04 MT to 0.11 MT of plastic trash into the sea every year. However, the amount of waste generated by a person in India is very low compared to that produced by a person in the US. In India, 0.34 kg of waste is produced per day by a person compared to as much as 2.58 kg by a person in the US. In India, only 3 per cent of the waste produced per day by a person is plastic compared to 13 per cent in the US.

The findings are staggering, says Nick Mallos, director, Trash Free Sea programme of Ocean Conservancy, a US-based advocacy group. If things continue unchecked, in 10 years we could see one pound of plastic for every three pounds of finfish, adds Mallos. The concerns are justified considering that global plastic resin production is growing at a fast pace. It registered a 620 per cent increase between 1975 and 2012. Most of this plastic resin is used for packaging, is quickly disposed of and could end up in the sea. In December, 2014, a study published in PLoS ONE revealed that there are 5.25 trillion plastic particles floating around in the sea.

As it would be difficult and expensive to remove plastic from the sea, researchers suggest it would be better to start managing waste. They suggest reduction of waste, expanded recovery systems and extended producer responsibility. The researchers also suggest that while infrastructure is being built in developing nations, industrialised countries can take immediate action by reducing waste and curbing the growth of disposable plastic. If per capita waste generation were reduced to the 2010 average (1.7 kg/day) in the 91 coastal countries that exceed it, and the per cent plastic in the waste streams were capped at 11 per cent (the 192-country average in 2010), a 26 per cent decrease could be achieved by 2025. This strategy would target higher-income countries and might require smaller global investments.

The study underscores the need to shift the ocean conservation dialogue from beach cleanup to waste management to ultimately preventing plastics from entering our oceans. There is evidence that this waste is detrimental to ocean wildlife. “We know that plastic is bad for ocean wildlife and habitats-animals ingest it or can get entangled in it; it litters beaches and can degrade sensitive reef systems. In lab studies, we have seen that plastic has negative impacts on animals that ingest it, and scientists have seen plastic’s impact on more than 660 species of ocean wildlife, including every type of sea turtle, as well as the majority of other marine species like whales, dolphins, seals, and seabirds,” says Mallos. “As far as human health goes, we don’t yet know the full extent of how plastics affect the ocean food chain. However, each new study makes us more, not less concerned,” he adds.

Science & Technology

What plants don't need

Light pollution has damaging effect on natural environment, including food chain

ARTIFICIAL LIGHT can affect the growth and flowering of plants and even the number of insects dependent on them for food. Researchers simulated street lighting on artificial grassland plots containing pea aphids, sap-sucking insects, at night. These were exposed to two different types of light—a white light similar to newer commercial LED lights and an amber light similar to sodium street lamps popular in the streets of the UK. The low-intensity amber light was shown to inhibit, rather than induce, flowering in greater bird's foot trefoil, a wild plant of the pea family and a source of food for the pea aphid in grasslands. The number of aphids was also significantly suppressed under the light treatment due to the limited amount of food available. This shows that light pollution can have a permanent adverse impact on wildlife and ecosystem. Philosophical Transactions of the Royal Society B, March 16

CLIMATE CHANGE
Vanishing ponds of the Arctic

Warming TEMPERATURES are shrinking ponds in the Arctic tundra. Rise in temperature thaws nutrient-rich permafrost, releasing nutrients into ponds and enhancing plant growth, which takes over shallow ponds. More than 2,800 ponds in the northern region of Alaska's Barrow Peninsula were analysedwith photos and satellite images between 1948 and 2010. The number of ponds had decreased by 17 per cent, while pond size had shrunk by an average of one-third. Journal of Geophysical Research: Biogeosciences, March 12

HEALTH
Folic acid reduces risk of stroke

Adults WITH hypertension can reduce the risk of heart attack by taking folic acid supplements along with the prescribed medication, enalapril. More than 20,000 adults with high blood pressure but without a history of stroke in China were given a daily treatment of a single-pill combination of enalapril and folic acid or a tablet containing enalapril alone. The first stroke occurred in 282 participants in the enalapril-folic acid group compared to 355 participants in the enalapril group. This represents a 21 per cent reduction in the risk of first stroke. JAMA, March 15

OCEANS
Low oxygen affects some fish

The LEVEL of oxygen in water affects certain species of fish. Deep waters of the West Coast, US, are low on oxygen. Fish species such as spotted ratfish and petrale sole are most sensitive and their presence has been found to decline sharply in the West Coast, while greenstriped rockfish and dover remain unaffected by dissolved oxygen levels. Such co-relation can affect the marine chain by driving fish into habitats that are less desirable for fishing. Fisheries Oceanography, March 11

Science & Technology 

Antacids weaken bones

Consumption interrupts absorption of calcium by the intestine

BE CAREFUL before you take your next antacid. According to a study, antacids make bones weaker. Stomach acid in the gastrointestinal tract helps the intestines absorb and transfer calcium to the skeletal system. But antacids interrupt and even stop the gut from absorbing calcium. This leads to weaker bones and increases the chances of fractures. Researches had indicated that antacids block the absorption of important nutrients, but it was not known how or why this was happening in the body. The new study could help find ways to treat common clinical conditions which are currently being treated with medications that make bones weak. PLOS Genetics, March 26

ECOLOGY
Decreased resilience

Ecosystems CAN be resistant to changing climatic conditions. But their resistance is lowered when they face natural or anthropogenic disturbances such as fires or insect outbreaks. A study on seven shrublands in Europe found them to be quite resistant to moderate experimental warming and drought. Plants are particularly sensitive to changes in the early stages of their life and even small climatic changes can result in vegetation shifts when ecosystems are disturbed. The understanding will help predict the response of ecosystems to climate change. Nature Communications, March 24

BIOLOGY
On way out

The TASMANIAN swift parrot is undergoing a population collapse and could be extinct in 16 years. The parrot is a major pollinator of blue and black gum trees which are crucial to the forestry industry. Ironically, its habitat is being destroyed by the industry. A five-year study which tracked movement and breeding habits of the parrot predicts that their numbers would halve every year and there is a 94.7 per cent chance of its extinction. Biological Conservation, March 25 (online)

CLIMATE
Antarctica on thin ice

The THICKNESS of Antarctica's floating ice shelves has decreased by as much as 18 per cent in certain areas in the past two decades. Data collected by satellite radar altimetry missions of the European Space Agency during 1994-2012 shows that the ice volume decline is accelerating. At the current rates, the ice shelves in western parts of Antarctica could lose half their volume in 200 years. Science, March 26