The occurrence of per- and polyfluoroalkyl substances (PFAs) in various environmental media is of great concern due to their potential adverse effects on living organisms. This project aims to investigate the feasibility of natural-occurring foams in aeration tanks for removal of PFAs and other contaminants of emerging concern from sewage.

PhD Thesis underway by Angel Chyi En We.

This project will explore the applicability of molecular approaches for taxonomic studies and rapid identification of invertebrates in a variety of freshwater habitats. This project delivered proof of concept for using DNA barcoding to fill taxonomic knowledge gaps and identify cryptic species and has also successfully discovered new populations of the critically endangered Mt Donna Buang Wingless stonefly.

PhD Thesis underway by Edward Tsyrlin.

Blue-green algae reduce water quality, especially when they produce toxins. Each algal cell can grow, reproduce all its DNA, and split into two ‘daughter’ cells, then those two ‘daughter’ cells produce four more until the numbers of algal cells bloom to extremely high numbers. High algal growth rates are associated with favourable environmental conditions (for the algae), stationary growth rates occur when the production of new cells is about the same as the number of dying cells, and if more cells die than are reproduced, the growth rate declines. The ability to predict or measure which of these three population growth rates is prevalent, and how much toxin is being produced, is information that the water industry needs to select the best methods for treating water. This project analysed the amount of DNA, and some specific sequences of DNA which correspond to the genes coding for toxins; and related the DNA analysis to actual counts of cells and measurements of toxin in water samples. This allowed the development of an improved and more informative technique for forecasting and monitoring toxic blue-green algae blooms.

Every day, Australians produce ~5 billion litres of wastewater, which contains a cocktail of chemicals. Industries that discharge wastewater are required to assess chemical risks to the receiving environments by conducting whole animal direct toxicity assessments (DTAs), which are expensive and pose an ethical dilemma. Our preliminary research shows that new in vitro bioassays provide an ethical and cost effective alternative that could be incorporated into DTA programs if their ecological relevance can be demonstrated. This project will develop and validate a new and internationally significant suite of in vitro bioassays for incorporation into DTA programs, leading to more ethical, cost effective and improved environmental protection.

Fish, frogs, and other aquatic animals sometimes show signs of ‘endocrine disruption’; aberrant changes to their hormone or reproductive systems that are thought to be caused by chemicals in the water they inhabit. Very few of these chemicals have been identified, and this prevents the use of classical chemistry-based analytical methods. The other problem is that the levels of hormone-like chemicals which have endocrine-disrupting biological effects tend to be so low that standard methods cannot detect them. This research developed a suite of biological tests sensitive enough to detect very low levels of chemicals associated with certain types of endocrine disruption. These tests were used to examine wastewater, surface water and drinking water collected from Australia, South Africa and four European countries. The water samples were also subjected to standard chemical analysis, and the datasets compared. It was concluded that some wastewater and surface water samples contained compounds that interacted with components of the estrogen, progesterone, androgen and mineralocorticoid hormone systems, but none of the biological tests detected endocrine disrupting activity in drinking water.

Cryptosporidium, a microscopic pathogen, forms infectious oocysts which are removed by specific and targeted water treatments. Oocysts can only be seen by using a microscope but finding an infectious dose of 10 oocysts in a litre of water is like finding a needle in a haystack. Usually a larger volume of water, 1000mL, is filtered to recover all the oocysts into a small volume of 0.1 to 1 mL, because this is small enough to be examined under a microscope. It is scientific practice to add some dead, colour-dyed oocysts to the large volume of water. If all the coloured oocysts are counted on the filter, the recovery is 100%. From this it became clear that there was a problem with oocyst recovery. This research found that different elements reduced recovery from different types of water, for example, iron and silica reduced oocyst recovery from river or groundwaters. The approved method for quantifying the environmental occurrence of oocysts can now be modified to increase recovery, and this change improves analysis and consequent management which further reduces risks to public health.

Blue-green algae are a nuisance, especially when they bloom and grow to high numbers in water storages and reservoirs. Traditionally, the water industry killed unwanted algae by adding copper sulphate. The problem is that this algicide is toxic and kills non-target species in the aquatic ecosystem. This project examined a range of alternatives by testing their practicality of application, efficacy, and cost.

Cyanobacteria and actinobacteria inhabit natural water sources. When they bloom, their very high numbers reduce water quality. These microscopic single-cell organisms produce toxins as part of their normal metabolism, and if the individual cells are damaged or broken, the toxins are released into the water, which makes them difficult to remove. Three of the most problematic toxins are ‘cylindrospermopsin’, which poisons the liver, ‘MIB’ (methylisoborneol) which makes water smell musty, and ‘geosmin’, which gives water an earthy taste. In this research project one chemical ‘sieve’ (reverse osmosis, RO) and two types of physical ‘sieves’ were used to filter the nuisance cells and their products out of water. The three processes (RO, ultra and nanofiltration) were also tried in various combinations to identify an integrated filtration and membrane system that best prevented damage to the cells, minimised leakage of nuisance compounds into water, and maximised the removal of cells, toxin and taste and odour compounds.