In maritime contexts there is a specific difference between flotsam and jetsam i.e. both are drifting materials that have come from a ship but flotsam has been washed overboard while jetsam has been jettisoned or thrown overboard. However, when we are on land items dropped to the ground seem to be simply referred to as litter regardless of the intent of the discarding party - I have even heard a tale of someone being approached as they left a cashpoint (or ATM) and asked if some cash they had dropped was theirs and on answering yes being fined more than that amount for littering.
I am looking for a word or phrase that distinguishes between litter that has been discarded intentionally and items dropped accidentally.
To add to the similarity to flotsam we have a situation locally where people correctly sorted their recycling and placed the containers (bags in our area) out for collection on the evening before collection was due but unfortunately it was the proverbial dark & stormy night so the area is now littered with wind scattered former recycling. This is the sort of situation that I would really like a concise description for.