单选题 Bangladeshi communities that are already being poisoned by arsenic-tainted(含砷)groundwater are facing an appalling new threat. Their rice and vegetables are also laced with high levels of arsenic. The health effects of eating such tainted food are not yet known, but the ramifications(门类)could be enormous. The WHO says contaminated drinking water alone could kill 270,080 Bangladeshis over the next decade. In a terrible irony, arsenic entered the Bangladeshi water supply when UNICEF and other international agencies sank millions of tube veils to provide clean drinking water. But the wells tapped into groundwater contaminated by arsenic from sedimentary deposits deep below Bangladesh. To deal with the problem, UNICEF and the World Bank have been testing water from wells and marking them safe or dangerous—but that testing program has been found to be flawed. To make matters worse, water from the wells is also used to irrigate paddy(水稻)fields. However, until now it wasn't known whether or not the rice was accumulating-arsenic. Tests on rice samples from around Bangladesh had found that arsenic levels did indeed vary according to the strength of local arsenic contamination in the soil and groundwater. Arsenic levels in different varieties of rice ranged from about 0.05 to 1.8 parts per million. In Europe and the US, levels are around 0.05 parts per million. The WHO recommends a maximum level of 0.01 parts per million in drinking water—but therefore, no guidelines for levels in foods. Ravi Naidu at CSIRO in Adelaide and his colleagues have been studying the uptake of arsenic from the soil by Bangladeshi crops. Their data shows that arum, a popular vegetable, has arsenic levels of nearly 150 parts per million. It is usually grown in wet zones adjacent to the tube wells. But some vegetables such as spinach and beans are relatively free from arsenic. The rice grains studied by Naidu's team had arsenic levels that ranged from undetectable to over 1.6 parts per million. Their calculations show that nearly 30 per cent of the total arsenic intake for people in Bangladesh may be coming from their food. If the body can absorb arsenic from food—and this is yet to be proven—then merely tackling drinking water contamination will not be enough. Researchers fear that paddy fields will continue to be irrigated from poisoned tube wells because Bangladesh does not have enough arsenic-free water for agriculture.

单选题 The central idea of the passage is about______.

单选题 From the passage we learn that water contamination of Bangladesh was caused by______.

单选题 The passage implies that the arsenic in drinking water in Europe and the US is______.

单选题 In order to reduce arsenic intake, the Bangladeshis should avoid eating______.

单选题 Which of the following is NOT true according to the passage?