This project aims to better understand chemical and biological hazards in Australia through long-term collection and analysis of wastewater and biosolids. Samples collected during the Australian Bureau of Statistics’ (ABS) Census 2021 will form the basis of a rich and unique databank that describes how communities are exposed to chemical and biological hazards, and how these chemicals/biological agents are released into the environment following wastewater treatment. The previous ARC-funded SewAus Census 2016 project (LP150100364), successfully established the first, globally unique nationwide program for wastewater-based monitoring of chemicals. SewAus Census 2016, demonstrated the utility of integrating wastewater-based monitoring with detailed, accurate data on the population that contributed to the sample from the Census. Demographic and socioeconomic data, such as age or occupation, were used to explain patterns of drug use and other chemical exposure in the population. A wide recognition of the value of this work forms the basis of this new proposal.

Together with existing and new stakeholders and end-users, a follow-up project has been developed to build on the outcomes of SewAus Census 2016 and address a new set of aims. This research has three overarching goals founded on:

• Advancing sampling and analytical methodologies to expand the scope and reach of wastewater-based monitoring in Australia;
• Measuring and understanding spatial and (long-term) temporal trends for chemical and biological hazards, and;
• Improving quantitative understanding of the sources and fate of chemical and biological hazards released to the environment from wastewater treatment plants (WWTPs).

Several cyanobacteria species are well known for their potential to produce cyanotoxins. However, not all genotypes of known toxin producing species produce cyanotoxins and of these there is significant variation in the spatial and temporal dynamics of toxin production. The water industry currently relies of observational measurement of the presence of ‘potentially toxic species’, toxin gene and toxin presence to inform management of cyanobacteria blooms in water supply storages. Predictive tools and preventative management are limited by a lack of simple environmental predictors to predict toxin production events. Understanding the drivers for toxin production that inform risk management frameworks would be of great benefit to water supply managers and to inform alternate management options. These tools would enable better responses to bloom events and allowing for the establishment of pre-emptive measures to minimize cyanotoxin production by targeted manipulation of environmental drivers.

Stormwater and treated wastewater can contain infectious pathogens. The Australian Guidelines for Water Recycling (AGWR) require that these are removed during recycling, and that recycling processes pass “Quantitative Microbial Risk Assessments” (QMRA). The problem is that these QMRA’s are often based on estimates. This research further developed methods (begun in WaterRA project 3002) to generate real-world measurements and data relevant to firefighters and domestic users because there are concerns that small amounts of recycled non-potable water might be inadvertently ingested. To test this, a harmless chemical, cyanuric acid, was added to safe water, then twenty-six volunteers used it, and a domestic high-pressure sprayer, to clean a full-sized model car for 10 minutes. The volunteers then collected their own urine for the next 24h because if this test-water is ingested, the cyanuric acid can be measured in the urine. From this it was discovered that the volunteers ‘drank’ an average of 0.13mL. This led to the conclusion that the conservative estimates in the AGWR currently protect domestic non-potable recycled water users, but that prolonged and/or high intensity occupational use of high-pressure sprays should be investigated further.

Recycled water usually contains extremely low levels of many different chemicals. The Australian Guidelines for Water Recycling (AGWR) require that some of these cannot exceed levels that would pose a risk to health, safety or the environment but there are concerns that one or more of these, or other, unmonitored micropollutants, might present a risk, or that chemicals that individually are harmless might add together and have undesirable effects. This research measured 300 organic micropollutants (listed by the AGWR) in a range of recycled waters and conducted a series of laboratory experiments. It was concluded that the toxic effects of individual chemicals often do add together but that this can be predicted accurately in most cases. Some disinfecting processes used to recycle water produce new micropollutants and it will never be possible to completely analyse the thousands of chemicals in any one water sample. These results led to the recommendation that classical chemical analytical measurement techniques should be complimented by a suite of bioassays which can quantify the total toxicity of all the mixed chemicals within recycled water.

Water treatment plant operators remove cyanobacteria and the toxins they produce from source waters but calculating the amount of treatment needed for effective removal is difficult, particularly in bloom conditions when cyanobacterial cell numbers and toxins change quickly. Current cell counting and toxin measurement can take hours or days to complete, and the results are not available quickly enough to help treatment plant operators respond to changing conditions. There is a need for a real-time method that gives instant results. This research examined the utility of fluorometers; probes that emit light that is ‘reflected’ back at different wavelengths by living cells and other matter in the water and is detected by the fluorometer. It was found that when only one species of cyanobacteria was present, there was a good correlation between the fluorescent signal and cell number, particularly when source waters were clear and not cloudy. Cell numbers did not relate well to levels of toxins or taste and odour compounds. When fluorometers were installed in 13 water treatment plants the correlation between cyanobacteria cell numbers and fluorometer signals was validated, and this led to the conclusion that fluorometers can give early warning of blue-green algae blooms.

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 (cyanobacteria) blooms decrease water quality by releasing toxins and unpalatable taste and odour compounds. The problem is that it is difficult to rapidly and accurately identify toxic cyanobacteria in drinking, recycled or recreational waters. This research developed a reliable and sensitive DNA-based PCR test which used robotic equipment to carry out the laboratory component of the test. The speed and accuracy of this diagnostic test has the potential to improve management of blooms and contribute to the maintenance of water quality.

Components of dissolved organic matter (DOM) and dissolved organic nitrogen (DON) in source waters can react with disinfecting chlorine or chloramine to form nitrogenous disinfection byproducts (n-DBPs) which might be toxic and hazardous to health. In this research, water samples were collected from nine water treatment plants and found to contain 28 n-DBPs. Total n-DBP formation, and particularly brominated n-DBP formation, was affected more by the levels of bromine in raw water than the different forms of nitrogen, and this led to the recommendation that it could be beneficial to monitor raw waters with high bromine concentrations. Although chloramination caused formation of more n-DBPs than chlorination, coagulation treatment decreased total DBP levels. Further research was recommended to characterise the toxicity of n-DBPs and to optimise the removal of DOM, DON and other n-DBP precursors by using GAC Acticarb in the treatment train.

Cryptosporidium, a microscopic single-cell parasite, forms an “oocyst” with a resistant outer layer analogous to an eggshell. Oocysts survive for a long time in the environment but UV in sunlight, and high temperatures that cause desiccation, kill them. If a mammal drinks water containing live oocysts, they embed in the gut wall and continue their lifecycle until eventually many more oocysts are excreted. There are 26 species of cryptosporidium but only five infect humans, and two; Cryptosporidium hominus and Cryptosporidium parvum, cause approximately 95% of all human infections. C. hominus occurs only in humans, but C. parvum is also found in cattle, sheep, and other animals. The problem is that human-infecting oocysts are excreted by animals in catchments and rain can wash live oocysts into water reservoirs. This research collated peer-reviewed published literature, and information and data collected by the water industry, then characterised the distribution of different Cryptosporidium species in Australian catchments. This led to recognition of a research need to track and predict live and dead oocyst transport during different weather events, and to model and evaluate catchment management initiatives such as excluding cattle from reservoir areas.