BUENOS AIRES - The Argentine government signed an agreement in early August with Australia for nuclear cooperation. The environmental watchdog organization Greenpeace says it means the South American nation will be importing nuclear waste.

The project calls for the construction in Sydney of a reactor to produce the radioactive isotopes used in medical, environmental, mining and agricultural research.

The nuclear agreement awards a contract to the Argentine company INVAP (Applied Research) and involves the treatment of spent nuclear fuel.

INVAP has committed itself to ''reconditioning'' - in Argentina or in third countries - the fuel required by the Australian reactor. The government and company officials have played down potential environmental risks.

MEXICO CITY - Conflicts between authorities have impeded the implementation of a program in the capital intended to improve air quality over the period 2001-2010. The start date had been scheduled for June.

The plan, drafted with the support of Mario Molina, a Nobel laureate in Chemistry, stipulates changes in the quality of gasoline, the creation of an environmental trusteeship and the coordination between authorities in the capital and in the suburban areas.

The recommended steps, which involve several ministries and organisms of the federal government, have not been taken due to lack of agreement and of resources.

But the plan will be launched soon, assure Mexico City's environmental officials. In the capital, 20 million people breathe optimal-quality air on less than 10 percent of the days each year.

RIO DE JANEIRO - The prolonged energy crisis in Brazil has prompted officials and experts to dig up old projects involving alternative and renewable sources of electricity.

Rice husks, previously considered a nuisance waste, are now the raw material for thermoelectric plants in southern Brazil. While in the northeast, a project is underway to replace diesel fuel with castor oil, which pollutes less and generates jobs.

The government is also considering reactivating a program to substitute gasoline with sugarcane alcohol, an initiative that had been on the decline since 1987. Sugarcane mills have expanded their production of electricity through the burning of cane pulp.

HAVANA - The European Unions has approved a Cuban project as a regional model for converting desert zones into areas of sustainable use, with Spain to lead the way in financial support beginning next year.

The plan involves investment to promote family self-sufficiency in production of vegetables and livestock, and the creation of employment sources for many of the 30,000 people living on the coast of Guantánamo, 971 km from Havana. Desertification, whether partial or total, affects a sixth of the province's area.

In 1999, Cuba received a United Nations-sponsored award for its efforts to fight desertification.