Blue-Green Algae Recreation Management Procedure Summary Queensland Bulk Water Supply Authority, Trading As Seqwater
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Managing Cyanobacterial Toxin Risks to Recreators A case study for Cylindrospermopsis raciborskii dominated inland lakes in South East Queensland Dr Cameron Veal – Technical Coordinator – Catchment Water Quality Contents • Seqwater at a glance • Recreation at Seqwater • Seqwater’s cyanobacterial risk profile • Setting recreational cyanobacterial triggers • Application of recreational triggers • Questions Seqwater at a glance • 26 Dams, 8 Rivers, 51 Weirs, 2 Borefields suppling 37 Water Treatment Plants. • Supply 298,524 ML of Treated Water to 3.1 Million People in South East Queensland. • $11.3 billion in built assets. • Manage 50% of green space outside National Parks with 2.6 million visitors. • Only own <5% of the open multi-use catchment. Recreation at Seqwater • Queensland Bulk Water Supply Authority is a merger of previous council run water assets. • South East Queensland Water (Restructuring) Act 2007 defines the Functions of the Statutory Authority • (f) using or managing its land in ways that benefit the community, including for recreational purposes; • Inherited different levels of historically permitted recreational activity. Recreation at Seqwater • On-water recreational access to 17 lakes. • The use of drinking water lakes for recreational activities can adversely affect water quality, not only for drinking water supply, but also ecological function and the on-going suitability for recreation. • Potential adverse effects must be weighed against the benefits to health and wellbeing of recreational water use. Seqwater and managed recreational water bodies • Primary recreation occurs on 11 of 17 approved on water recreational storages. Healthy communities, Prosperous region. Recreational Water Quality Management Plan • Guidance from NHMRC (2008) and ADWG (2011) • Cyanobacterial susceptibility scores: Very Poor • 9 out of 17 recreational lakes not recommended for recreational activities. • Biovolume driven Cyanobacterial Management Plan • Seqwater has a mandate to provide recreational opportunities of regional significance in SE Qld. • Science, monitoring resource and technical skills. • Targeted local cyanobacterial guidelines for whole of company management of cyanobacteria. • Focus on Potentially Toxic Species (PTPs). Cyanobacterial Management Plan • Information derived from the most current published and relevant grey literature available. • Inherent water quality risks. • Primary and Secondary Recreation Risk. • Seqwater is opening lakes to recreation when conditions are suitable. Recreational Cyanobacterial Triggers • Limitations with Proxy Indicators: assumes worst case scenario until proven otherwise, i.e. all blooms are highly toxic until proven otherwise. • The Alert Level Framework accounts for both species of known toxicity and those of unknown toxicity by using cell concentration/biovolume. • The basis for these triggers is centred on guideline values set for exposure to cyanobacterial toxins through ingestion. • The values are defined in the ADWG and NHMRC as guidelines (in the case of microcystin and cylindrospermopsin) and alert values (in the case of saxitoxins and nodularins) for drinking water. Recreational Cyanobacterial Triggers • NHMRC (2008) guideline using a Lowest Observed Adverse Effect Level (LOAEL) from the 44-day pig study of Kuiper-Goodman et al (1999). • The calculated guidelines are 10 mg L-1 for children and 44 mg L-1 for the average adult. The child exposure guideline for microcystins (measured as total microcystins and expressed as microcystin-LR toxicity equivalents). • Aim to protect the sensitive population and adopt the exposure guidelines for children. Recreational Cyanobacterial Triggers • For cylindrospermopsin, saxitoxins and nodularins no guideline is currently defined due to lack of adequate data. However, health alerts have been proposed through the ADWG. • Due to the similarity between toxicity of nodularins and microcystins, the guideline for microcystins can be adopted as a suitable alternative for managing risks from exposure to nodularins. • Assuming a conservative ingestion rate of 200 mL (double that used in NHMRC (2008)), a threshold concentration that is 10 fold greater than the drinking water threshold can be derived. Recreational Cyanobacterial Triggers • Baseline monthly integrated five metres sample with laboratory analysis trigger escalated sampling frequency based on biovolume, cell counts of PTP’s or toxins above guideline values. • Visual Inspection can also trigger escalation or closures. • Need BV + Red Level 1 auxiliary trigger. • Toxin ≥ GL. Recreational Cyanobacterial Triggers • Targeted toxin testing, with a catch all for other PTP’s. • Cost limitation. Recreational Cyanobacterial Triggers Secondary Recreation BV Trigger Primary Recreation BV Trigger Recreational Cyanobacterial Triggers C. raciborskii Recreation RL1 Trigger Recreational Cyanobacterial Triggers Combined Cylindrospermopsin Toxin Trigger Challenges • Long closure periods resulting is significant local community discomfort. • Significant summer sampling and analysis program (350 samples per month) with long standard turn around times. • Discrepancies between phycologists analysis of the same slide can result in opening/closing recreational water bodies. • Cell count to biovolume conversion and cell counts to toxin limitations. Future options • Move away from proxy indicators and focus on more affordable and rapid indications of the actual toxin present, with escalated monitoring skewed towards the bloom degradation stage. Summary • Seqwater needs to permit recreational access to open multiuse catchment and storages. • Cyanobacterial biovolume alone is not suitable for Seqwater’s recreational management needs. • Localised cyanobacterial guidelines for South East Queensland enable better management of cyanobacterial risk. • A scientifically rigorous escalation and de-escalation cyanobacterial and toxin sampling program enables recreational storages to be opened when conditions permit. Questions Blue-green Algae Recreation Management Procedure summary Queensland Bulk Water Supply Authority, trading as Seqwater. ABN: 75 450 239 876 Level 8 117 Brisbane Street, Ipswich QLD 4305 PO Box 328 Ipswich QLD 4305 P 1800 771 497 F +61 7 3229 7926 E [email protected] W seqwater.com.au Translation and interpreting assistance Seqwater is committed to providing accessible services to people from culturally and linguistically diverse backgrounds. Please contact us and we will arrange an interpreter to share this publication with you. ISBN-13:978-0-9943790-1-6 © Seqwater 2016 This publication is correct at time of writing and is subject to change. B Contents Introduction Introduction 01 Seqwater is responsible for providing a safe, secure About blue-green algae 02 and cost-effective drinking water supply for more than Contributing factors to growth 02 three million people across South East Queensland. Future climate change 03 Helping to prevent blue-green algal blooms 03 We are one of the few bulk water providers in Australia that Despite their beneficial functions, blue-green algae can Algal blooms in our lakes 03 manages open catchments, allowing the community to enjoy sometimes pose significant risks to human health and our Blue-green algae toxins 04 our water storage lakes and catchment land for recreational lifestyle by producing toxins and odorous compounds. Exposure to cyanotoxins and health risks 05 activities. Our challenge is to balance community access with Consuming fish or crustacean flesh and organs our essential role of providing high quality drinking water. A number of guidelines and protocols are in place to help from algae-affected water 05 Public safety is our priority. We take a proactive and water authorities protect recreational users from risks related Risks to children 05 conservative approach to safety at our recreation areas, to blue-green algae exposure, including the: Recreation at Seqwater storage lakes 06 restricting access to water-based activities when there is a • Australian Drinking Water Guidelines Primary and secondary recreation 06 potential public health or safety concern due to microbial risks • Australian Guidelines for Water Quality Monitoring and Monitoring blue-green algae 07 or the presence of cyanobacterial toxins. Reporting, and Alert levels for recreation 08 Cyanobacteria (commonly referred to as blue-green algae) • Guidelines for Managing Risks in Recreational Water and Restricting lake access for water-based are naturally occurring organisms and are amongst the Management Strategies for Cyanobacteria (blue-green recreational activities 09 earliest known life forms on this planet, believed to be algae): a guide for Water Utilities. Fish consumption guidance from Queensland Health 10 partly responsible for the development of life through the Seqwater’s Cyanobacterial Management Plan and Alert Level Keeping our communities informed 11 oxygenation of the earth’s atmosphere. Framework for Cyanobacteria and Recreation Procedure Blue-green algae can exist in both salt and fresh water, and are provides an overarching framework and uniform process for an important part of a healthy ecosystem, performing functions managing blue-green algae risks to recreational users at our such as photosynthesis, nitrogen fixation and nutrient cycling water storage lakes. We have embraced national protocols and in the food chain. Blue-green algae are also sometimes used to standards, and developed local water quality guidelines that grow food, make fertilisers and