Analysts used four years of monitoring data from all of the country’s 84 bathing waters to determine the quality.
Among the worst waters were Portobello West in Edinburgh, Yellowcraigs in East Lothian and Stonehaven in Aberdeenshire.
Conversely 17 beaches were deemed as “excellent” under the new standards.
A total of 38 waters were rated as “good” and 12 as “sufficient”.
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Analysts said the new EU classification system provided a “more consistent picture” of water quality and puts a greater emphasis on information provision for beach users and bathers. Calum McPhail, Environmental Quality manager at Scottish Environment Protection Agency (Sepa , said: “It is encouraging to see that the majority of Scotland’s bathing waters are performing so well under the new directive which has introduced much stricter standards for bathing water quality.
“However, we understand that some local communities will be disappointed, as we are, that 17 bathing waters have been rated as having a ‘poor’ EU classification, and many will be concerned when the new classifications are displayed on these beaches for the first time this month.”
Sepa announced it was preparing improvement plans to help each of the “poor” bathing waters to meet at least the “sufficient” standard by 2020.
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These will focus on delivering actions to address any problematic sources of pollution and improve the use of information and advice on when to avoid bathing, such as during abnormal incidents or short periods of increased risk of pollution following heavy rainfall.
Mr McPhail said that just because the water quality had been deemed as sub standard it should not put people off visiting the beaches.
He said: “It is important to remember a ‘poor’ classification does not necessarily mean that water quality is continually poor, and in many cases this is due to historic episodes of reduced water quality following heavy rainfall.
“These are still fantastic beaches to visit, and our network of electronic information signs provide advice and details about any current water quality issues at the majority of these bathing waters.”
VisitScotland said marine recreation and tourism expenditure was worth an estimated £3.7 billion a year to Scotland.
A spokesman said: “We are pleased the vast majority of bathing waters are classified as sufficient or above, while 65 per cent have an excellent or good classification.
“It is very disappointing, however, to hear the water quality at some beaches have not met Sepa bathing water standards and we will be discussing the potential impact this could have on tourism with the organisations involved.”
Aberdeen, Anstruther, Arbroath, Carnoustie, Cullen Bay, Dunbar, North Berwick and Troon were among those rated as “good”
And included in the “sufficient” classification were Irvine, Leven, Lunderston Bay and Thurso.
Scotland’s best and worst beaches
Crail (Roome Bay)
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