'Swimmability' : a key element for communities to safely engage with Australian urban rivers

Australia’s largest cities are growing, and this is placing increasing pressure on urban waterways. There is a growing awareness that the quality of life in Australian urban communities is enhanced through the engagement of people with healthy urban rivers. Swimming, boating, and fishing in many Australian urban waterways are popular recreational activities. Swimming and other activities associated with waterways contributes to quality of life in urban communities. Swimming in urban rivers can be risky. Hazards include dangerous currents, aquatic plants, submerged hazards, algal blooms, and unsuitable water quality. In Sydney, Australia’s largest City, swimming is popular in the Hawkesbury-Nepean River. Data from showed that E. coli levels in the river occasionally exceeded safe recreational guidelines for human health. The results are not reported to the public. We believe that it is more important than ever that government, industry and scientific bodies work to protect and improve the water quality of Australian urban rivers as our cities grow. Sharing this information with the community needs to consider education programs, public forums, and timely communication of the current state of local Australian urban rivers regarding their ‘swimmability’

Elevated sodium concentrations in Australian drinking water supplies

Salt in the drinking water of many Australian water supplies could be adversely contributing to the ill-health of many people. Health care professionals often recommend low-sodium diets for patients with kidney disease, heart disease and cardiovascular disease. It is recommended that people on a low-sodium diet drink water with less than 20 mg/L of sodium. The sodium concentration of water supplies in many regional and remote regions of Australia often had water with elevated sodium (more than 20 mg/L) in their water supplies. In NSW 17 of the 21 regional water supplies tested had higher than 20 mg/L sodium. The issue of elevated sodium in many Australian drinking water supplies needs to be recognised more prominently. Sodium needs to be sampled more frequently and the results shared openly with consumers and health professionals. All water authorities that provide drinking water with sodium concentrations higher than 20 mg/L should be advising their customers of this fact as a high priority. People on low-sodium diets that have >20 mg/L sodium in their water supply should consider options to obtain low-sodium water

Comparison of sympatric freshwater turtle populations from an urbanized Sydney catchment

1. Australian freshwater turtles are widely distributed throughout the continent, and in each river catchment there are at least two taxa. In south-eastern Australia Chelodina longicollis and forms of Emydura macquarii cohabit within a waterway, although they have been shown to partition habitat within the water column in non-urban bodies of water. Limited comparative data are available for the urban populations. 2. Within urban Sydney C. longicollis (eastern long-necked turtle) and Emydura macquarii dharuk (Sydney short-necked turtle) share habitat. However, in contrast with non-urban studies of C. longicollis and other sympatric E. macquarii taxa, it was observed that the population profile of the two species was similar at all sites, and that C. longicollis were present in greater numbers than E. m. dharuk. 3. The continued degradation of preferred habitat, low recruitment, and potential competition from introduced turtles place both species in a precarious position. 4. The shallow, impounded waterways of the regulated urban bodies of water align more closely with the preferred habitat of C. longicollis than with that of forms of E. macquarii, which prefer deeper flowing waters or large wetlands adjacent to rivers. Emydura m. dharuk may be at greatest risk of extinction in urban areas. 5. Across urban Sydney, the low numbers of E. m. dharuk compared with C. longicollis may be due to the lack of mobility of E. m. dharuk such that individuals tend to be stranded in sub-optimal habitat. In contrast, C. longicollis has a greater propensity for overland movement, and a preference for the 'new habitat' resulting from urban impacts on the associated waterways, and thus appears to be able to utilize these modified urban waters more successfully

The use of citizen scientists to confirm the presence of platypus (Ornithorhynchus anatinus) in north-west Sydney

The platypus is an elusive species. Traditionally they have been hunted for their fur and now face several threats including drought, pollution and like many of our Australian icons, habitat loss from urbanisation. Sydney is undergoing rapid urbanisation. The population of platypus in Sydney is not well studied, is not well documented and poorly acknowledged. The aim of this project was not only to confirm the presence of platypus in the Cattai and Little Cattai Creek catchments in north-west Sydney but to get the community excited and engaged with waterway health using the platypus as an umbrella species. Working with a local volunteer community environment group, Cattai Hills Environment Network, a media campaign was conducted for the wider community to identify possible ‘hotspots’ which resulted in the mapping of 18 sample sites. Community members were recruited as citizen scientists to conduct simple environmental DNA (eDNA) sampling over a weekend in June 2020. Samples at eight out of the 18 sites contained platypus DNA which confirmed the presence of platypus in the north-west of Sydney. Using citizen scientists, lay members of the community, to be a part of this project, to take ownership in collecting data and contributing to the project allowed the community to connect with the waterways. The more that the community connect with the waterways the more they will work and advocate to protect it. This project could be adapted more broadly, not only for platypus in Sydney, but as a template of a successful citizen scientists project

Impact of mining and industrial pollution on stream macroinvertebrates : importance of taxonomic resolution, water geochemistry and EPT indices for impact detection

This study investigated freshwater macro invertebrate communities in waterways contaminated by active and abandoned mining and industrial activities in order to ascertain any impact on freshwater ecosystems. We compared macro invertebrate communities at the species, family and order levels of taxonomic resolution. We also collected water samples to compare ionic composition and metal concentrations from waste affected and reference (non-affected) sites. In addition to assessing ecological impairment, the study also sought to determine whether the degree of sensitivity in detecting any impairment varied according to the taxonomic level of identification used. We calculated the biotic indices of EPT richness and taxonomic richness at the species, family and order levels, and performed multivariate analyses to measure differences in community structure at all three levels. We found significant differences in both biotic indices and macro invertebrate community structure at each taxonomic level, indicating ecological impairment at waste affected sites. We also concluded that the most appropriate taxonomic level for evaluating macro invertebrates depends on the information required. In this study, the family level provided the clearest assessment of ecological impairment at waterways affected by mining and/or industrial wastes, and order-level data provided only a marginally less sensitive measure of this impairment

Effects of wetland water source on a population of the Australian eastern long-necked turtle Chelodina longicollis

This study investigates the impacts on the Australian native eastern long-necked turtle Chelodina longicollis of wetland waters derived from (1) precipitation and groundwater flow and wetlands also supplemented with (2) irrigation runoff from agricultural lands, (3) tertiary-treated sewage effluent and (4) harvested stormwater. Influences of water quality parameters on population attributes of the turtle population are considered. A total of 951 C. longicollis were captured in a mark-recapture study over 8 months. Overall, a female sex ratio bias was observed, and a larger number of smaller turtles were found in wetlands not contaminated by recycled tertiary-treated effluent. Dissolved oxygen, temperature, surface area and emergent vegetation had the greatest impact on turtle population structure. The lower the dissolved oxygen, the smaller the surface area of the wetland, and the higher the percentage of emergent vegetation, the greater the number of juveniles present. Water quality parameters which would be detrimental to fish predators appear to provide a ‘safe haven’ for juvenile turtles at the most vulnerable life stage of turtles

The presence of illicit compounds in the Hawkesbury-Nepean river system

Emerging environmental pollutants include compounds that are not routinely monitored but which have the potential to cause adverse ecological impacts. Here we report on the presence and environmental fate of illicit compounds in the Hawkesbury-Nepean river system. The occurrence of illicit compounds including; amphetamine, cocaine, MDMA, and associated metabolites were found in WTP discharge locations at levels that were in some instances, above those reported in similar international studies. The persistence of these compounds is not limited to the immediate discharge area, with detectable levels measured at distances downstream. Our results highlight that the management of WTP discharge requires an increased understanding of the fate of these emerging environmental pollutants in the rapidly urbanising Sydney landscape

Variations in illicit compound discharged from treated wastewater

The detection and monitoring of illicit drug concentrations in environmental waters is of increasing interest. This study aimed to determine if illicit and regulated compounds, their potential pre-cursors, and metabolites varied in amount discharged into the environment from treated wastewater at different facilities. Water samples were taken from discharge points of four different tertiary wastewater treatment plants discharging directly into the Hawkesbury-Nepean River (Australia) on two different occasions and analysed to determine the concentrations of compounds including: ephedrine, pseudoephedrine, amphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, methamphetamine, cocaine, and benzoylecgonine. Here, we show that detectable levels of illicit drug and metabolites are being emitted on a consistent basis after having persisted through the wastewater treatment process. The concentrations of methamphetamine are in excess of previously reported surface water concentrations. The estimated total load of compounds being discharged on a daily basis is greater than similar sized catchment areas. The results presented here are of concern from both an ecological and human health perspective

Water quality and ecological recovery of a mountain stream after 60 years of receiving sewage effluent

In 1980 the sewerage system of the Blue Mountains (NSW) townships was inadequate. It had 12 overloaded sewage treatment plants (STPs) that provided incomplete treatment that caused widespread pollution of its streams. The last major STP discharge to be removed was Blackheath STP. It was permanently closed in June 2008. This study was conducted over 15 years. We used stream macroinvertebrates to measure the ecological changes that resulted following the STP closure. This began when it was still operating in 2003, then 16 months later (2009), and then in 2018, almost 10 years after its closure. This case study was a rare opportunity to study the recovery of a previously chronically impaired freshwater stream by decades of receiving poorly treated sewage wastes. We used a replicated quantitative ‘kick sampling’ technique and identified invertebrates to the family level to measure ecological health recovery of the small headwater stream. We found that the degree of ecological recovery was large but not complete, indicating a possible residual disturbance remaining. We suggest that one of the important factors that has enabled the recovery to date was the clean water quality and environmental condition of Hat Hill Creek upstream of the pollution

The effect of water quality, macroinvertebrate assemblages and habitat suitability on the distribution of Platypuses : a pilot study in Cattai Catchment, North West Sydney

The platypus (Ornithorhynchus anatinus) continues to persist in urban waterways with high pollutant concentrations, altered flow regimes, channel morphology, and degraded stream substrate and riparian zones. The purpose of this study was to determine whether water quality, specific habitat features, and macroinvertebrate assemblage influences the distribution of platypus as inferred by eDNA detection in a selection of 13 sites within the Cattai catchment, in North West Sydney. Sampling took place on two separate occasions: June 2020 and December 2020. Platypus eDNA was detected in 9 of the 18 sites and 5 of the 9 waterways surveyed. Platypus activity was strongly associated with the quality of their stream habitat (riparian vegetation, absence of sand and silt accumulation, and streams lacking dense growth of macrophytes). Platypus also appeared to avoid streams with ‘higher salinity', and lower dissolved oxygen. The effective conservation of this iconic species in peri-urban and urbanised catchments such as that of Sydney requires ongoing monitoring of population status and health, and prevention of further habitat damage by informed local population management strategies. This study indicates that the loss of riparian vegetation, an increase in aquatic weeds and increased sedimentation are important factors in developing local stream management improvements to sustain the population of platypus in the Sydney basin