SIQUIRRES, Costa Rica — Every other day, a truck travels down the dusty road flanked by palm trees outside Hilma Duartes' home in the heart of pineapple country here, carrying cisterns of clean drinking water. In the past, Duartes — like 82 percent of all Costa Ricans — drank clean water from the sink. But now, she said that "we only use the tap for cleaning the house and washing clothes.” The change, she said, is the result of water pollution that emerged with the booming pineapple business in her community of Milano more than five years ago.