The Anne Arundel County Health Department has issued a warning against contact with water in Tar Cove at Pasadena's Sillery Bay after bacteria levels shot up last week.
Residents should not use the cove for activities such as swimming or personal watercraft use until the advisory has been lifted, health officials said.
County inspectors test water quality at 101 beaches weekly, every other week or once a month during the summer months, said Health Department spokeswoman Elin Jones.
Friday's report on Tar Cove showed elevated levels of enterococci, organisms found in the digestive systems of warm-blooded animals.
High levels of these bacteria indicate the presence of fecal matter in the water, Jones said.
The U.S. Environmental Protection Agency says 104 organisms per 100 milliliters of water is acceptable.
Last week, Tar Cove registered a sudden increase - 330 organisms per 100 milliliters, Jones said. Other tests conducted during the past month showed 10 organisms, she added.
`Definitely an increase'
"That was definitely an increase," Jones said.
The Health Department has posted yellow signs in the area warning people against swimming or other recreational activities that entail direct contact with water, she said.
Anyone who comes in contact with the water is advised to wash well with soap and water immediately, Jones said. The person's clothing also should be washed.
Fish caught in Tar Cove are safe to eat if cooked thoroughly, she said.
Those who come into contact with contaminated water could be at risk of illnesses such as swimmer's ear, an infection of the outer ear.
Other ailments might occur if water is swallowed or enters an open wound or abrasion.
Water inspectors usually test Tar Cove twice a month, but they will return weekly until bacteria levels return to safe levels, Jones said.
The Health Department will lift advisories after levels have been back to normal for at least two days, according to the department's Web site.
Health inspectors will conduct further studies to determine the cause of the problem, although heavy rainfall last week might have been the culprit, Jones said.
The department posts water-quality reports about Tar Cove and other Anne Arundel recreational areas on its Web site.
Advisories and closings also are announced on the department's water-quality line, 410- 222-7999.
For more information about water testing, go to aahealth. org/wqleadin.asp.