Ten beaches on the South Shore have been closed to swimming in the wake of Wednesday's rain.

Landing Road Beach in Duxbury had a bacteria level almost 30 times the maximum considered safe.

In Scituate, Bassings (Sailing Club), Sand Hills, Lighthouse, Peggotty and Humarock beaches were all over the limit, but by less than 100 percent. Humarock and Peggotty beacheswere also closed last week.

Wollaston Beach was posted as a precaution. Bacteria levels were well within acceptable levels.

The other 51 salt-water beaches on the South Shore are open after passing the latest round of bacteria tests, but many were sampled before the storm.

See water quality test results for each community and for Cape Cod, the South Coast and North Shore.

For more on Quincy beaches, call 617-376-1288, or visit ledger-quincy-beaches. For more on Wollaston Beach, call 617-626-4972.

HOW BEACHES ARE TESTED



Beaches are tested for intestinal bacteria found in humans and animals.



High levels indicate the possible presence of disease-causing microbes that are present in sewage but are more difficult to detect. Bacterial colonies are filtered from three ounces of water and placed on a gel infused with nutrients and chemicals designed to promote growth.



Left in an incubator, the single cells isolated on the filter grow explosively, forming colonies visible to the naked eye. After one day, the colonies are counted and if they exceed 104 colonies, the beach is closed to swimming.