BEIJING/SINGAPORE, March 25 (Reuters) - Most base metals fell on Monday, with Shanghai copper heading for its biggest drop since August, as investors worried about the prospect of a recession in the United States, the world's biggest economy. U.S. Treasury 10-year note yields dropped on Friday below three-month Treasury bill yields for the first time since 2007 after disappointing U.S. manufacturing data. A yield curve inversion is seen as a leading recession indicator. "That indicates a recession is ahead so the market is really concerned about this inversion. Copper as a proxy of the economy is affected. That reflects how Chinese investors understand about the copper market," said Helen Lau of Argonaut Securities. FUNDAMENTALS * COPPER: The most traded May copper contract on the Shanghai Futures Exchange (ShFE) fell 1.7 percent to 48,240 yuan ($7,186.06) a tonne at 0345 GMT. That is the lowest price since Feb. 18. Three-month copper on the London Metal Exchange edged up 0.1 percent at $6,319 a tonne after declining by 1.7 percent last week, its biggest weekly decline since December. * COPPER STOCKS: Copper stockpiles in ShFE warehouses CU-STX-SGH dipped slightly to 259,172 tonnes last week. A rapid build during a seasonal lull in demand in February pushed copper stockpiles to a nine-month high by mid-March. "The Shanghai market has more downside risks than the London market given that the inventory levels are different," Lau said. * COPPER: Peruvian police said they have arrested the leader and two lawyers of an indigenous community, accusing them of trying to extort Chinese miner MMG Ltd by blocking a road it uses to transport copper for the past month. * ANTOFAGASTA: Chile's Antofagasta expects to reach an agreement with miner BHP Group to help ensure water supply at its Zalidvar copper mine in the country's northern desert, a company official told a Chilean newspaper on Friday. * GLENCORE ZINC: Glencore said that its McArthur River zinc operations in northern Australia were returning to normal after a cyclone over the weekend. * OTHER METALS: Most other metals were down across the board, with Shanghai nickel shedding 1.7 percent, while London nickel lost 0.9 percent and London aluminium decreased 0.4 percent. * ALUMINIUM: China Hongqiao Group said on Friday that a doubling of alumina sales helped offset lower aluminium production and prices, leaving its net profit steady in the second half of 2018. * CHINA: China reverted to being a net importer of alumina in February for the first month since April 2018, while its scrap metal imports plunged to just 160,000 tonnes, the lowest in customs website records going back to June 2014. Scrap copper imports stood at 60,000 tonnes.