Blue-green algae season prompts review of EIS reports

With the annual season for blue-green algae (BGA) blooms reaching its peak between February and April, Queensland property developers and environmental consultants are being urged to check that plans for man-made water features and other disruptions to the water system have taken into account the potential for a toxic BGA bloom.

Cyanobacteria and alga scientist Lindsay Hunt, from Jarvis Hunt Consultancy, said the risk of a BGA bloom and appropriate mitigation strategies should be considered during the planning stages of any urban or industrial development.

“Artificial water bodies and the redirection of established water courses create new ecologies that can differ significantly from the natural ecosystem, posing particular challenges for maintaining water quality in the longer term,” Ms Hunt said.

“One of the biggest issues facing developers - and the engineers, hydrologists and environmental consultants they engage - is having access to reliable, accurate data about the phytoplankton or micro-flora in the catchment areas and in existing man-made water bodies.”

What are BGAs? 

Cyanobacteria, commonly referred to as BGAs, are a group of photosynthetic microorganisms that survive and flourish in all kinds of ecosystems. They are usually too small to be seen; but when they form large colonies (‘blooms’) the mass can take on a paint-like appearance on the water’s surface.

However, not all BGAs form scums, so it may not always be obvious. This is why reliable, timely and accurate monitoring and toxin analysis is essential.

BGA impacts 

While not all BGA blooms contain deadly toxin-causing bacteria, they can impact upon the quality of drinking water and the safety of water-based recreational activities.

Water containing high numbers of cyanobacteria cells can smell and taste unpleasant. Fish that are caught may not be edible. The water may cause skin irritations and respiratory distress for people who are susceptible.

Ms Hunt recommends that environmental impact studies include mitigation strategies for these potential risks to the aesthetic and functional objectives of development and long-term management plans.

“It’s very important that the development’s stakeholders understand what might happen when introduced flora and fauna interact with other nutrients and pollution collected in the local water.

The need for specialist expertise

“Distinguishing the many different species of phytoplankton in water requires expert training and knowledge, but not all water testing facilities are set up or have the skillset to provide accurate reports on levels of BGAs or the toxins they produce,” Ms Hunt said.

Jarvis Hunt Consultancy has introduced new services to help developers and their teams gather reliable data specifically about the potential for BGA blooms. If there is a likely to be problem, the developer can be confident of making informed and cost-effective decisions about mitigation.

“Partnering with Jarvis Hunt at the planning, development and review stages adds value to a project,” said Ms Hunt.

“For example, we can identify water quality changes to help predict what kind of events might occur. We can assess how the shape, depth, turbidity of the water and turnover will affect the physical and chemical profile of the water column.

“These initiatives can help with monitoring and managing the issues that might reduce the attractiveness, useability and safety of the proposed ornamental lake or new drainage system.”

Jarvis Hunt Consultancy was established in 2013 in response to the growing demand for reliable, specialist services in the quest for optimal water quality, ecological balance, and sustainable management systems.

“We help clients dealing with phytoplankton and cyanobacteria management achieve optimum water quality.

“With our extensive experience working in NATA and quarantine accredited production laboratories, we can coordinate scientific analysis and solutions to keep local water supplies safe and healthy,” Ms Hunt said.

About Blue Green Algae (Cyanobacteria)

• Blue-Green Algae (BGA) occur naturally in most marine and freshwater aquatic systems.
• Cyanobacteria have been found in the planet’s oldest fossils and created the atmosphere that made all current life on earth possible.
• When there is an imbalance of the levels of BGA in an ecosystem, some species can produce toxins that have serious health implications for humans, animals, birds and livestock.
• A bloom is identified as a discernible increase in algal numbers causing changes to the water’s colour, taste, odour, turbidity, as well as impacting on the health of other aspects of the ecosystems, such as birds, fish, frogs, etc.
• Cyanobacteria blooms can occur in any warm, still or slow-moving freshwater that contains nutrients such as fertiliser runoff or septic tank overflows, including rivers, streams, wetlands, natural and man-made lakes, dams, estuaries, inlets, bulk water reservoirs, irrigation channels, stormwater drains, sewers, and wastewater treatment plants.
• BGA blooms usually flourish in the summer months when warmer temperatures, increased rainfall and incidence of flooding can change the levels of nutrients entering an ecosystem.
• BGA blooms in cooler months are often caused by unusually high levels of nutrients flowing from floods and rainfall.
• Signs of the environmental impact from BGA blooms include odour and taste changes, but the primary one is the discolouration of the water to verdant green and or vibrant blue, and a foam or scum-like layer on top of the water.
• Dense blooms can block sunlight and consume all the oxygen in the water, killing off other plants and animals.
• Toxins associated with cyanobacteria have been known to damage the nervous system and liver, upset the gastrointestinal system, and promote tumour growth.