Blue-Green Algae (Cyanobacteria) in Inland and Inshore Waters: Assessment and Minimisation of Risks to Public Health Compiled by the Scottish Executive Health Department Blue-Green Algae Working Group ©Crowncopyright2007 ThisdocumentisalsoavailableontheScottishExecutivewebsite: www.scotland.gov.uk RRDonnelleyB5089104/07 Furthercopiesareavailablefrom Blackwell’sBookshop 53SouthBridge Edinburgh EH11YS Telephoneordersandenquiries 01316228283or01316228258 Faxorders 01315578149 Scottish Executive Health Department 2007 Emailorders Revised Guidance [email protected] w w w . s c o t l a n d . g o v . u k Blue-Green Algae (Cyanobacteria) in Inland and Inshore Waters: Assessment and Minimisation of Risks to Public Health Compiled by the Scottish Executive Health Department Blue-Green Algae Working Group Scottish Executive Health Department 2007 Revised Guidance ScottishExecutive,Edinburgh2007 ©Crowncopyright2007 ISBN978-0-7559-5391-2 ScottishExecutive StAndrew’sHouse Edinburgh EH13DG ProducedfortheScottishExecutivebyRRDonnelleyB5089104/07 PublishedbytheScottishExecutive,April,2007 Furthercopiesareavailablefrom Blackwell’sBookshop 53SouthBridge Edinburgh EH11YS Thetextpagesofthisdocumentareprintedonrecycledpaperandare100%recyclable Blue-Green Algae (Cyanobacteria) in Inland and Inshore Waters: Assessment and Minimisation of Risks to Public Health Revised Guidance Contents Page no. Foreword Preface Glossary of abbreviations 1 Introduction 4 2 Occurrence and appearance of blue-green algae 5 3 Public health concerns 6 4 Local action plans 8 5 Assessing the nature and intensity of blue-green algal blooms 9 General provisions Defining an assessment programme Visual inspections Sampling and analyses 6 Assessments of the risks to human and animal health 12 Responsibilities for risk assessments Types of risk assessment Content of risk assessments for individual waters Defining categories for frequency of occurrence or risks for algal blooms Templates for risk assessments Specific considerations for public drinking water supplies 7 Action 15 General requirements Triggers for action Actions in response to an algal bloom Action to prevent algal blooms 8 Information 21 9 Enforcement 22 10 Investigation 27 Annex A Membership of Working Group 28 Annex B Blue-green algal toxins 29 Annex C Sources of specialist advice 30 Annex D Suggested framework for a Local Action Plan (LAP) 32 Annex E Recognition and identification of blue-green algal blooms, scums and mats and methods for sampling 33 Annex F Suggested templates for risk assessments 37 Annex G Extract on exposure guidelines from the WHO Document 39 Annex H Suggested text for warning notices 44 Annex I Media briefing notes 45 contents Blue-Green Algae (Cyanobacteria) in Inland and Inshore Waters: Assessment and Minimisation of Risks to Public Health Revised Guidance Foreword by Dr Harry Burns, Chief Medical Officer for Scotland In the autumn of 1854, an outbreak of cholera claimed the lives of some 600 residents of the Soho area of London. In studying the distribution of these cases in the areas affected, a local doctor, Dr John Snow, developed a view that the source of the outbreak was the water pump in Broad Street. It is said that, at a subsequent meeting, Dr Snow managed to convince a sceptical board of guardians for the parish of St James, that there was sufficient evidence to warrant an appropriate intervention – the removal of the Broad Street pump handle. The handle was removed and the outbreak ended. The story of Dr John Snow and the Broad Street pump handle holds a prominent place in the history of public health in the UK. Not only did it establish contaminated drinking water as the source of a major killer, it is also credited with marking the birth of modern epidemiology. Now, some 150 years on, protection of the public health relies less on the inspired efforts of individuals but rather on what we often describe as “the organised efforts of society”. However, ensuring the availablity of reliable sources of clean water remains a cornerstone of these efforts. The original development of this document in 2002 and the subsequent implementation of its guidance have provided an excellent example of successful channelling of the organised efforts of the public health and the environmental agencies in Scotland. This joint working has continued in the development of this 2007 revision which now includes the provisions necessary to address the relevant responsibilities of the Scottish Executive under the European Council’s revised Bathing Waters Directive of 2006. I am grateful, therefore, to the members of the Blue Green Algae Working Group who have contributed to the revision of this document and I thank them for the opportunity to provide this introduction. Dr Harry Burns Chief Medical Officer for Scotland 1 of 46 This is the first revision of the guidance document under the same title that was published by the Scottish Executive Health Department in 2002. The approach advocated for managing the risks to human and animal health of exposure to blue-green algal toxins continues to centre on production and implementation of “Local Action Plans”. These should be co-ordinated by the NHS Boards in Scotland and should be agreed by the various stakeholders identified herein. This document includes guidance on the content and structure of these Local Action Plans and should be regarded as a resource to assist in their production, as well as fulfilling there requirements of Article8 (Cyanobacterial risks)of the Bathing Waters Directive(2006/7/EC). The Scottish Executive Health Department (SEHD) proposes to review and, if necessary, re- issue this guidance document every five years. However, it is recognized that the value of this guidance lies in its practical implementation. The SEHD would therefore welcome feedback ,which should be addressed to the SEHD’s Scientific Adviser at St Andrew‘s House, Edinburgh EH13DG. Should this feedback indicate a specific need, then a further version of this guidance will be produced sooner. Dr Colin Ramsay Chairman of the Blue Green Algae Working Group 2 of 46 Blue-Green Algae (Cyanobacteria) in Inland and Inshore Waters: Assessment and Minimisation of Risks to Public Health Revised Guidance Glossary of abbreviations COSHH Control of Substances Hazardous to Health EHO Environmental Health Officers FSA Food Standards Agency HSE Health and Safety Executive HPS Health Protection Scotland LPSs Lipopolysaccharides LAP Local Action Plan LAs Local Authorities LAEH Local Authority Environmental Health MHSWR Management of Health and Safety at Work NPIS National Poisons Information Service SAC Scottish Agricultural College SACVSD Scottish Agricultural College Veterinary Science Division SEPA Scottish Environment Protection Agency SEERAD Scottish Executive Environment and Rural Affairs Department SEHD Scottish Executive Health Department SEMD Security and Emergency Measures Direction SPIB Scottish Poisons Information Bureau WHO World Health Organisation 3 of 46 1 Introduction 1.1 This report provides guidance to Directors of Public Health, to Heads of Environmental Health in local authorities and to others in Scotland on possible risks to public health of blue-green algae (cyanobacteria) in inland waters. The guidance, prepared by a Working Group established by the Scottish Executive Health Department, updates that given in the guidance document under the same title that was published by the Scottish Executive Health Department in 2002. It takes account of current World Health Organisation (WHO) guidance summarised in “Toxic cyanobacteria in water. A guide to their public health consequences, monitoring and management” (eds I Chorus and J Bartram) published in 1999 by E&FN Spon, London, on behalf of the WHO. The guidance given in this report also provides for Scottish compliance with the requirements of Article 8 of the revised Bathing Water Directive (2006/7/EC). 1.2 The remit of the Working Group was: i. to review previous guidance in the context of advances in scientific knowledge and, in particular, to consider the implications for the public of exposure during recreation and work and of exposure from food and water; ii. to review previous guidance on monitoring and risk assessment in the context of recent experience in Scotland and elsewhere; and iii.to provide further guidance. 1.3 The membership of the Working Group is given in Annex A. 1.4 This document will continue to be updated every five years. It is accepted, therefore, that while certain details (such as contact details in Annex C) are correct at the time of issue, they are subject to obsolescence during this period. 4 of 46 Blue-Green Algae (Cyanobacteria) in Inland and Inshore Waters: Assessment and Minimisation of Risks to Public Health Revised Guidance 2 Occurrence and appearance of blue-green algae 2.1 Blue-green algae occur in fresh-, brackish- and sea-waters throughout the world; in Scotland, they can occur in quantity in lochs, ponds, canals, reservoirs and coastal waters. While usually green, or blue-green in colour, they may be khaki, blue, black, dark brown or red. 2.2 When present in high concentrations, colonies of blue-green algae can often be seen with the naked eye: they may resemble fine grass cuttings or take the form of small irregular clumps or pinhead-sized spheres. Blue-green algae in high concentrations in the water column form ‘blooms’ and, when blown on to a downwind shore, form scums which may be centimetres thick. Scums may also be seen in slow-flowing rivers and streams downstream from lochs. Decaying scums, due to other naturally-occurring microbes or bright sunlight for example, can appear bleached as sky-blue, grey or white masses. 2.3 Blue-green algae may also grow on the bottom of shallow water bodies and on shoreline rocks. They occasionally form thick gelatinous mats, which may be exposed as the water level falls or may detach from the bottom and reach the shoreline. These mats are usually very dark in colour (black, dark brown or green) and cohesive and are sometimes mistaken for sewage. 2.4 Some types of algae especially blue-green algae form surface scums and growths of some water plants, particularly duckweed, might be mistaken for blue-green algae. 5 of 46 3 Public health concerns 3.1 Surveys in different parts of the world have found that between about 45% and 90% of blooms of blue-green algae produce toxins. These toxins are largely retained within the blue-green algal cells during their development and growth phases and are released, in the main, on cell death. 3.2 Blue-green algae of several genera can produce a range of toxins including neuro- and hepatotoxins and lipopolysaccharides. An algal bloom may contain more than one species, each producing the same or different toxins, either singly or in combination. In addition, the toxicity of one species might change over time to a pattern that might vary for different places on a particular water body. Further information on algal toxins is given in Annex B. 3.3 Evidence of toxicity comes from reports of the effects of exposure of people and of animals to algal blooms and from laboratory investigations of algal toxins. 3.4 In 1989, a group of soldiers took part in canoe training, including rolling and swimming exercises, at Rudyard Lake in Staffordshire. Two became severely ill with atypical pneumonia; others reported abdominal pains, vomiting, diarrhoea, blistering of the mouth and sore throats. Further incidents of effects on human health have occurred after recreational contact with blue-green algal scums and blooms in UK inland waters in recent years. The effects were probably associated with exposure to blue-green algae and ingestion of the toxin-containing blue-green algal scum. 3.5 Gastroenteritis, neurological effects and acute hepatocellular damage have been reported from other countries. Illnesses and deaths of haemodialysis patients, probably resulting from blue-green algal toxins in inadequately-treated water, occurred in Brazil in 1996. Further exposures of haemodialsis patients to blue-green algal toxins, followed by illness, occurred in Brazil in 2001. 3.6 Ingestion of hepatotoxic and neurotoxic scums of blue-green algae are reported to have caused the deaths of cattle, sheep, dogs and birds. There is also evidence that blue-green algal toxins have been major contributors to fish kills and deaths of other aquatic animals. 3.7 Another potential source of intoxication for both animals and humans is bioaccumulation of algal toxins in the food chain. The principal concern here would be accumulation of algal toxins in shellfish including freshwater and brackish-water mussels and in fish. However, no cases of intoxication from this source have been reported to date in Scotland. 3.8 Episodes of blue-green algal contamination of drinking water supplies occur periodically. In September 1997, a massive blue-green algal bloom affected the main water supply loch on Westray, Orkney Isles, and resulted in a ban on the use of water for drinking, cooking and washing. Large quantities of water treatment chemicals were needed to reduce blue-green algal concentrations to a level where even a reduced throughput could be maintained and aluminium levels in the final water eventually rose to a level considered unfit for consumption. The water had also become unacceptable due to taste and odour. No blue-green algal toxins were detected. The water authority arranged for potable water to be transported as bottled water and in tankers to serve the human population. Fortunately, the very large 6 of 46