 It's Friday mass in downtown Manila. As usual, it's standing room only. This is a densely populated city, home to around 12 million people. Manila is situated on this bay. An important body of water for fishing, transportation and commerce. But rapid population growth, a boom in building and pollution from farming, are turning it into one big dumping ground. The Pasig River is one of the waterways that flows into the bay. It brings all kinds of waste with it. We have many sources of pollution here so as you can see we have many industries, some factories, we also have a couple of households living nearby. And agriculture is also a main contributor to pollution here. Efren and his colleagues make regular trips to the waterways around the city. They collect samples of plants, water and sediments from the bottom of the rivers. These contain important information about levels of pollution in the water and where it comes from. Some pollution may be visible, but to identify what it actually is and how it may affect animals and humans, special techniques and equipment are used. This is done at the laboratories of the Philippine Nuclear Research Institute in Manila. Scientists use isotopic and nuclear techniques to analyse the samples. Using a technique known as mass spectrometry, they can identify the different pollutants contained in the sample. By studying this data further, they can even detect the actual source of the contamination. Another technique uses sediments taken from the bottom of the sea. Samples prepared from different layers of sediment cores are placed in an alpha spectrometer. By measuring the radioisotopes which decay over time, the scientists can give a date to the samples and determine when the pollution took place. The IAEA has been supporting the Philippines' efforts in marine protection for over 20 years. We have a good partnership with the agency, so we benefit a lot from them on the job trainings, regional workshops, so all the funding also they provide as well as the equipment. But this is not just a Manila problem. More than half of the world's population lives on or close to the water's edge. 80% of the pollutants in the oceans and along the coastlines come from man-made land-based sources. The IAEA operates projects in over 50 countries worldwide that promote the use of nuclear techniques in marine pollution management. I think the most important part is that we get knowledge about the levels and finally the impact and the risk to the population, the risk to food, to marine food because marine food is one of the major protein sources for mankind. And we help our member states to be aware of the pollution. We help the member states to be able to measure these pollution, all these chemicals, all these radioactive substances which are finally ending up in the oceans. Cities like Manila will continue to grow and develop. More people will flock to the capital in search of a better life they probably won't find. This will mean more damage to the already overburdened bay. If the authorities make good use of the information provided by the scientists there may be a chance to rehabilitate the bay and prevent further pollution.