Beach pollution and other hazards

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Almost three quarters of our main beaches were assessed by the EPA in 2018 to be of ‘Excellent’ quality. However, five bathing waters failed to meet the minimum required standards highlighting that more needs to be done to provide a greater level of protection for bathers at beaches and inland areas vulnerable to sewage pollution. Beach users should be entitled to feel safe from harm from the water they swim in when they spend a day at the beach. There are a number of potential hazards which exist ranging from sewage pollution to man-made issues such as plastic pollution.


Sewage is possibly the most significant hazard that can affect the water quality of our beaches whether as a result of untreated sewage discharges or the operation of combined sewer overflows (CSOs) after rainfall. This is usually evident by discolouration in the water or a strong smell. Contact with such contaminated water can cause gastro-intestinal illness. If this persists see your doctor.


Fortunately in our environment the risk of chemical spillages is very low. These will generally be evident from discolouration or as an oily film on the water. Avoid contact if at all possible and wash the skin with soap and water.

Plastic pollution

Plastic pollution can occur in the form of micro-beads such as those found in personal care products but more often it is evident on beaches as large litter such as plastic bags, drinks bottles etc. As well as spoiling the beauty of our beaches, plastic can be toxic if ingested by marine life and any litter is an attraction for seabirds and rodents. Seagull poop can be just as contaminating as dog faeces so bag your litter and take it home with you.


Algae are a natural phenomenon and are common enough in freshwater lakes in early spring and during the summer months. These take on many forms but one group known as ‘Blue-Green’ algae because of their colouration can produce toxins which can cause skin irritation and have been associated with fatalities in dogs which have ingested this material. If the lake water looks green avoid contact.


Seaweed is common on our coastline and although at times a little unsightly around the high watermark it is part of the natural ecosystem and is normally not cleaned up by local authorities unless it presents a health risk. The most common forms around Ireland’s coast are ‘bladder wrack’ and kelp.  In some areas however there has been a growth of what is commonly called ‘sea-lettuce’ – a lush bright green form of a marine algae called Ulva.  This occurs in nutrient rich waters. There is no specific health risk however it can give off a smell like rotten eggs when it decays.


There are many species of jellyfish which are natural to Irish coastal waters such as the common jellyfish with four round circles on its body or the Compass jellyfish with radiating brown lines on its body . In recent years however we have seen the occurrence of more exotic species of jellyfish such as the Lion’s Mane and Portuguese Man O’War. These have long stinging tentacles and should be avoided even when dead as they can produce skin lesions which may require medical attention.  It is a common belief that urinating on such stings or treating then with vinegar will help but this is not the case. Wash the affected area with water and try and remove any tentacles with a gloved hand. In cases of sever exposure seek medical attention. See HSE Jellyfish stings advice.

Weaver fish

The weaver (or weever) fish is a small sandy coloured fish which lives in Irish coastal waters. It spends most of its time out of sight under the sand in warm waters around the low tide mark. It has a small dorsal fin which protrudes above the sand and if trodden on it will release a powerful toxin in to the bloodstream which can cause painful swelling and numbness. If this occurs seek medical attention. One danger is that the toxin can cause anaphylactic shock and has been associated with fatalities. Wearing swim shoes can help reduce the risk.

EPA Bathing Water Team