If you were disturbed by the damage done to Cambodian coastal fisheries by the industrial-scale dredging of sand for sale to Singapore, as shown in the new documentary short “The Lost World,” there’s good news: the practice has largely been shut down in Koh Kong, the area featured in the film. The bad news is that environmentally destructive sand mining continues in other parts of Cambodia, throughout Southeast Asia, and in fact around the world.

Since the mid-’00s, fishers in villages in the mangrove-rich estuaries of Koh Kong province have complained that rampant sand mining was wiping out the crabs and fish that provide their living. Many families have had to send members to work in garment factories in