Hong Kong - When Hong Kong intercepted yet another huge shipment of illegal African ivory in early October, it added to a growing headache for authorities: What exactly do you do with one of the world's biggest stockpiles of elephant tusks?Government warehouses in the former British colony are holding more than 30 metric tons of smuggled ivory seized since 2008, as customs agents intercept a surging amount of endangered animal products being smuggled to mainland China to meet demand from the country's newly wealthy.The latest shipment, 189 tusks worth $1.5m hidden in soybean sacks in a shipping container, was one of four major busts this year.Ivory is known as "white gold" because of the rich prices it commands on the black market. Hong Kong has put values of between $1 000 and $2 000 a kilogram on ivory it seized this year. A 2011 report by the International Fund for Animal Welfare said buyers in China were paying up to $2 400 a kilogram.Booming economyConservation groups, worried the ivory pile presents a target for theft and fails to send a signal that Hong Kong is serious about cracking down on the trade, urge the government to destroy it. Authorities are resisting, instead preferring to dole out small amounts to schools to raise conservation awareness."As long as that ivory is kept anywhere, it will always be a temptation for people to get their hands on it," said Grace Ge Gabriel, the fund's regional director.IFAW and 15 other animal welfare and conservation groups wrote to Hong Kong's leader and customs commissioner after the October seizure, urging them to follow the example of countries that destroy confiscated ivory.Because the ivory trade is illegal, its size worldwide is hard to pin down. Samuel K Wasser, director of the Centre for Conservation Biology at the University of Washington, calculated it was worth $264m from 2000-2010. He said the amount now is likely to be far higher based on the soaring amount confiscated globally.IFAW estimates 35 000 elephants a year are killed by poachers for ivory, risking extinction of the animal in the wild.Demand is fuelled by China's booming economy, which has created a vast middle class with the ability to buy ivory carvings prized as status symbols."The Chinese market remains the paramount destination for illicit ivory," according to a report this year by the UN, the Convention on International Trade in Endangered Species and wildlife trade monitoring network Traffic.It said China's involvement has been growing since 1996 despite "increasing levels of law enforcement".Stockpile theftIn their letter, the groups pointed to "high profile ivory destruction measures" over the years. Kenya held the world's first large ivory bonfire in 1989, torching 12 tons in an event that drew international attention and helped lead to a global ban the following year on ivory sales between countries. Zambia set fire to 9.5 tons in 1992 and Gabon burned nearly 5 tons in 2012.In June, the Philippines became the first Asian country to destroy its stocks when it burned and crushed more than 5 tons of ivory worth an estimated $10m confiscated since 2009. The United States last week destroyed more than 6 tons of ivory tusks, carvings and jewellery seized over 25 years and urged other nations to follow suit.Hong Kong's stockpile is several times bigger. Destroying it would be a mammoth task. The government won't disclose the exact amount, though says the bulk of it is made up of 32.6 tons seized since 2003, with amounts rising sharply in recent years. Some 7.2 tons have been confiscated so far in 2013, double the amount in 2011.Other busts this year include $5.3m in ivory, rhino horns and leopard skins from Nigeria in August; $2.2m of ivory from Togo in July; and a $1.4m shipment from Kenya in January."It's a financial burden on a country to keep such a stockpile," said Gabriel, adding that ivory has been stolen from stockpiles in other countries.‘Exploring destruction’Last year, thefts were reported at government vaults in Zambia and Botswana. In 2006, 3.7 tons vanished from the Philippine inventory.Government officials say the Hong Kong stockpile is monitored by CCTV and security guards, but won't reveal its location for security reasons.Members of a committee advising the government on endangered species are opposed to the destruction. According to minutes of a meeting last year, they worried it would be seen as wasteful and believed the best option was to donate small amounts to schools. The government says it is "exploring destruction" and will consult the committee when it has a concrete proposal."Education plays a vital role for the seized ivory. Usually, we send the ivory to schools for showcasing and educational events," said Azaria Wong, a conservation department officer. "We hope the children can feel the importance of preservation of endangered species."Schoolgirl Lucy Skrine, aged 11, disagrees. She and a friend have started an online petition calling for the government to destroy the stockpile.She says giving it to schools so they can put it in a display case with an explanatory note is not very effective unless it's accompanied by an education campaign. She said friends at another school that has received donated ivory report that "students are just passing by and admiring the ivory".