A year from now the world's sports stars will have convened on London for the opening ceremony for the 2012 Olympic Games. Six venues are already completed, well on schedule. But how green are the venues that have been built across the capital and will the games contribute to the environment?

Controversy originally surrounded the original site over fears of the displacement of natural wildlife, the ecological impact and the ongoing sustainable legacy for the park, but the Olympic organising committee allayed fears with a renewed commitment of their determination to ensure 2012 would be the greenest Olympics games yet.

The Aquatics Centres is the latest venue to be finished. It's 160 metre wave adorning the Zaha Hadid building is a distinctive addition to the London skyline. It joins the Olympic Stadium, Velodrome, Handball Arena, Basketball Arena and the International Broadcast Centre as the other completed venues.

Work began on the Aquatics Centre over three years ago. Over three thousand people have worked on the construction, with an effort to ensure products used have been sustainably sourced from the UK, including steel from North Wales and under-floor heating from Newcastle-upon-Tyne.

Sustainable design in the centre includes the use of 30,000 sections of low-carbon ethically sourced Red Lauro timber. The eye-catching wave on the roof is made of steel, covered in aluminium half of which has been recycled. There has been a reduction in chemicals used in the plastic seating and where possible the impact on the environment generated by moving goods to the Olympic Park has been reduced, the ceramic tiles used in the pools for example were transported by train.

Andrew Altman, Chief Executive of the Olympic Park Legacy Company, said, "The Aquatics Centre will be a unique facility in London that puts sport at the heart of regeneration. As a focal point for community, national and international swimming, it will sit at the centre of the south plaza - London's newest public space which will welcome visitors to the Queen Elizabeth Olympic Park after the Games."

In the other venues, the Olympic Stadium is described as the greenest yet. It has been built using low carbon concrete, which sees a 40% reduction in the use of carbon. On the roof of the stadium, the decorative structural rings have been made using recycled gas pipes. The stadium itself has been built in a basin in the ground ensuring less steel and concrete has been used in construction. In comparison with other Olympic stadia the London stadium is 75% lighter in terms of steel. Other features on the park include the 3,000 sq m recycled external copper cladding on the Handball Arena and the 100% natural ventilation in the Velodrome.

Across the rest of the Park work has been done tor educe the environmental impact of the construction process. Surveys were carried out on the plants and animals whose natural habitat was in the Park and they have been re-homed. Much of the space was a brownfield site so the land was cleaned of any chemicals and waste while waterways and greenway footpaths have been cleaned.

However the sustainable legacy of the Games has been questioned by some politicians who have called for an investigation into the green impact in surrounding areas post 2012. The London Assembly's environmental committee is to review the commitment made to the local community in Stratford once the Games are finished. The Olympic park will be renamed the Queen Elizabeth II Olympic Park and 10,000 new houses will be built.

Murad Qureshi, chair of the environment committee, said, "Bold promises were made about how environmentally-friendly the Stratford site will be. We want to investigate how these commitments on its legacy will be fulfilled once the excitement of the Games is over.

The Olympic Park offers the potential to create a wonderful new area of the capital that promotes a more sustainable way of living. We need to ensure this becomes a reality in order to secure a long-term legacy for London."