Out of our depth?

For most families, the biggest risk of holidaying beside the sea is dropping ice creams in the sand. But there are also dangers that lurk at the sea shore. Although swimming is one of the best forms of exercise for the heart and lungs, it can also be lethal. Drowning is the third most common form of accidental death (after road accidents and accidents in the home) and research shows that most deaths occur in the first three minutes, often to fit and healthy young men.

For most families, the biggest risk of holidaying beside the sea is dropping ice creams in the sand. But there are also dangers that lurk at the sea shore. Although swimming is one of the best forms of exercise for the heart and lungs, it can also be lethal. Drowning is the third most common form of accidental death (after road accidents and accidents in the home) and research shows that most deaths occur in the first three minutes, often to fit and healthy young men.

Coastguards assisted in the rescue of more than 150 swimmers who got into difficulties and 39 people who were swept into the sea last year, but a survey revealed that almost three quarters of adults did not know about the dangers posed by tides and currents. In all, 320 people drowned: 40 more than in the previous year.

The death of 18-year-old Jerry O'Toole was one that apparently defied explanation. He was a volunteer on a sail-training ship who fell overboard off Liverpool bay one April afternoon in the mid-Nineties. The captain reported seeing him on the surface, conscious and clearing the hair from his face. Within five minutes he was face down in the water.

The explanation was cold shock. Sudden cooling of the skin, for those unaccustomed to swimming in cold water, can cause an initial gasp reflex followed by uncontrolled rapid breathing, a very rapid heart rate and a surge in blood pressure. The swimmer takes a couple of strokes, the reflexes mount up and then he loses the strength to swim.

Sea water can be a restorative, speeding healing of cuts and grazes (because of the salt), but it also carries health risks. More than 300 million tons of raw and partially treated sewage is discharged around the UK coastline each day, together with four million tons of toxic waste every week, and they have been linked with illnesses ranging from ear infections to bacterial dysentery, pneumonia and hepatitis.

Last month, an outbreak of diarrhoea and vomiting among a group of schoolchildren at Gwithian beach in Cornwall was blamed on the polluted "Red" river, which empties into the sea at Godrevy point. Twelve out of 14 children on the trip from Mullion school were affected, as were four surfers who used the beach between 12 and 15 July.

A similar outbreak claimed the life of Heather Preen, aged eight, who was on holiday at Dawlish Warren, Devon, in 1999. She had been walking with her family when she splashed in a storm outflow stream that is thought to have been contaminated with raw sewage. She was infected with E Coli 0157, a lethal form of the bacterium that causes gastro-enteritis. Although the source of the infection was never confirmed, at the inquest into her death the coroner said the storm outflow should have carried a notice warning visitors of the risks.

Vicky Garner of Surfers Against Sewage (SAS), an environmental pressure group, said: "This is a grey area. Beaches fly blue flags [indicating they are safe] but the water quality changes from hour to hour. The flags are awarded on the basis of last year's water quality. So the public are not informed about what is happening in the water at the time they are on the beach."

A warning was posted at Trevaunance Cove, St Agnes, Cornwall last month, on the orders of the Environment agency, advising bathers not to use the beach after a pump failure led to a discharge of sewage into a stream that runs down to the cove. South West Water, which was responsible for the failure, was blamed for 11 pollution incidents in 2002, making it the worst water company in Britain.

Fears of pollution have led an increasing number of surfers to seek vaccination against hepatitis A, according to SAS. Research shows that the virus, which targets the liver and can cause serious illness, can survive for 100 days in salt water.

But bacteria are not the only risk. Flotsam and jetsam also threaten the unwary bather. The wreckage of RMS Mulheim, which ran aground off the north coast of Cornwall in the spring, has been turning up on beaches all summer. Lastyear the Coastguard agency responded to 2,700 incidents involving individuals and nearly 5,000 involving boats. More than 250 people were cut off by the tide, some 200 were trapped on cliffs and 53 got stuck in mud.