Jackie H. Myers

Ecological evidence links adverse biological effects to pesticide and metal contamination in an urban Australian watershed

Summary: Aquatic ecosystems near urban areas are often ecologically impaired, but causative factors are rarely identified. Effects may be revealed by considering multiple lines of evidence at different levels of biological organization. Biological impairment is evident in the urban section of the Upper Dandenong Creek Catchment (Victoria, Australia). We assessed whether episodic sewage spills or other pollutants were the cause of poor ecological condition in the stream. The evidence evaluated included chemical and invertebrate assessments, caging studies of mudsnails Potamopyrgus antipodarum, antioxidant biomarkers and endocrine disruption-related endpoints in fish (Carassius auratus and Gambusia holbrooki) and toxicological studies with chironomids (Chironomus tepperi). A combination of metals and pesticides is likely to be affecting the aquatic fauna across all biological levels, with macroinvertebrate communities, P. antipodarum and C. tepperi populations and C. auratus individuals all ecologically impaired. Adverse alterations to aquatic fauna were consistently seen in Bungalook Creek and persisted downstream of this confluence into Dandenong Creek. In addition, chemical assessments and toxicity identification evaluation (TIEs) resulted in several point sources of both metals and pesticides being identified as origins of impairment. This contrasted with an expectation that adverse effects were likely to be associated with sewer-related pollution. As a consequence, target areas and specific pollutants were identified for remediation instead of an expensive sewer upgrade. Synthesis and applications. The results demonstrate that it is important to investigate biological effects in different taxa, in both the laboratory and field, to understand which stressors are causing adverse effects on faunal assemblages. When adverse effects are seen across multiple levels of biological organization and caused by the same pollutant from an identifiable source, there is a clear

Altered reproductive behaviours in male mosquitofish living downstream from a sewage treatment plant

Freshwater environments are common repositories for the discharge of large volumes of domestic and industrial waste, particularly through wastewater effluent. One common group of chemical pollutants present in wastewater are endocrine disrupting chemicals (EDCs), which can induce morphological and behavioural changes in aquatic organisms. The aim of this study was to compare the reproductive behaviour and morphology of a freshwater fish, the mosquitofish (Gambusia holbrooki), collected from two sites (wastewater treatment plant (WWTP) and a putative pristine site). The mosquitofish is a sexually dimorphic livebearer with a coercive mating system. Males inseminate females using their modified anal fin as an intromittent organ. Despite this, females are able to exert some control over the success of male mating attempts by selectively associating with, or avoiding, certain males over others. Using standard laboratory assays of reproductive behaviour, we found that mosquitofish males living in close proximity to WWTP showed increased mating activity compared to those inhabiting a pristine site. More specifically, during behavioural trials in which males were allowed to interact with females separated by a transparent divider, we found that WWTP-males spent more time associating with females. Concordant with this, when males and females were subsequently allowed to interact freely, WWTP-males also spent more time chasing and orienting towards the females. As a result, females from both sites showed more interest towards the WWTP-site males. Male anal fin morphology, however, did not differ between sites. Our study illustrates that lifetime exposure to WWTP-effluents can greatly affect male behaviour. The results underscore the importance of behaviour as a potential tool for investigating unknown contaminants in the environment.

Androgenic activity of effluent from forty-five municipal waste water treatment plants in Victoria, Australia

It is well known that waste water treatment plant (WWTP) effluents are estrogenic. There has been much less consideration of the androgenic activity of WWTP effluents. To partly address the shortage of information on androgens in Australian WWTP effluents, in August 2006, and again in 2007, we collected discharges from up to 45 Victorian WWTPs (~25% of all WWTPs in Victoria), grouped by treatment process, i.e. activated sludge, extended aeration, and lagoon based treatment, and measured the total estrogenic, androgenic, retinoic acid, and aromatic hydrocarbon hydrogenase activity of the effluents using a hybrid yeast bioassay. This paper will concentrate on the androgenic activity and male hormone concentrations.

Herbicides and trace metals in urban waters in Melbourne, Australia (2011-12): concentrations and potential impact

Urban stormwater samples were collected from five aquatic systems in Melbourne, Australia, on six occasions between October 2011 and March 2012 and tested for 30 herbicides and 14 trace metals. Nineteen different herbicides were observed in one or more water samples from the five sites; chemicals observed at more than 40% of sites were simazine (100%), MCPA (83%), diuron (63%) and atrazine (53%). Using the toxicity unit (TU) concept to assess potential risk to aquatic ecosystems, none of the detected herbicides were considered to pose an individual, group or collective short-term risk to fish or zooplankton in the waters studied. However, 13 herbicides had TU values suggesting they might have posed an individual risk to primary producers at the time of sampling. Water quality guideline levels were exceeded on many occasions for Cd, Cu, Cr, Pb and Zn. Similarly, RQmed and RQmax exceeded 1 for Cd, Cr, Cu, Mn, Ni, Pb, V and Zn. Almost all the metals screened exceeded a log10TU of −3 for every trophic level, suggesting that there may have been some impact on aquatic organisms in the studied waterbodies. Our data indicate that Melbourne’s urban aquatic environments may be being impacted by approved domestic, industrial and sporting application of herbicides and that stormwater quality needs to be carefully assessed prior to reuse. Further research is required to understand the performance of different urban stormwater wetland designs in removing pesticides and trace metals. Applying the precautionary principle to herbicide regulation is important to ensure there is more research and assessment of the long-term ‘performance’ standard of all herbicides and throughout their ‘life cycle’. Implementing such an approach will also ensure government, regulators, decision makers, researchers, policy makers and industry have the best possible information available to improve the management of chemicals, from manufacture to use.

Potential triggers of akinete differentiation in Nodularia spumigena (Cyanobacteriaceae) isolated from Australia

Nodularia spumigena, like many cyanobacteria, produces specialised reproductive structures, known as akinetes, which are believed to allow survival under unfavourable conditions. This study investigated the effects of salinity, nitrogen and phosphorus concentration at two irradiances on akinete differentiation in a N. spumigena isolate from the Gippsland Lakes, Victoria, Australia. A computer image analysis program was used to photograph filaments and assess production of akinetes over time in separate experiments for each environmental parameter. Heterocyst production and cell morphology were also examined. The results suggest that akinete production increases over time. Production of akinetes is further increased at low and high salinities and with the addition of nitrate. Higher irradiance increases akinete differentiation, although in combination with different phosphorus concentrations causes varied effects. The development and sedimentation of akinetes may provide an inoculum for reoccurring blooms. Heterocysts were only observed during experiments with varying salinity and nitrogen exposures. Light quantity appeared to play a large role in heterocyst production. The ability of N. spumigena to produce akinetes and heterocysts is likely to be part of the reason for its success and continual occurrence in estuarine environments low in nitrogen, such as the Gippsland Lakes, Victoria, Australia. Factors known to reduce heterocyst and akinete production will provide new insight to possible management controls for this species.

Municipal wastewater effluent licensing: A global perspective and recommendations for best practice

Advances in wastewater treatment have greatly improved the quality of municipal wastewater effluents in many parts of the world, but despite this, treated wastewaters can still pose a risk to the environment. Licensing plays a crucial role in the regulation of municipal wastewater effluents by setting standards or limits designed to protect the economic, environmental and societal values of waterbodies. Traditionally these standards have focused on physical and chemical water quality parameters within the discharge itself, however these approaches do not adequately account for emerging contaminants, potential effects of chemical mixtures, or variations in the sensitivity and resilience of receiving environments. In this review we focus on a number of industrialised countries and their approach to licensing. We consider how we can ensure licensing is effective, particularly when considering the rapid changes in our understanding of the impacts of discharges, the technical advances in our ability to detect chemicals at low concentrations and the progress in wastewater treatment technology. In order to meet the challenges required to protect the values of our waterways, licensing of effluents will need to ensure that there is no disconnect between the core values to be protected and the monitoring system designed to scrutinise performance of the WWTP. In many cases this may mean an expansion in the monitoring approaches used for both the effluent itself and the receiving waterbody.

Impacts on the seagrass, Zostera nigricaulis, from the herbicide Fusilade Forte® used in the management of Spartina anglica infestations

The herbicide Fusilade Forte® (FF) is widely applied in agricultural weed management and in the management of the invasive saltmarsh grass, Spartina anglica (ricegrass or cordgrass). FF (active ingredient fluazifop-P acid, FPA) is selective for poaceous grasses. Its primary mode of action is inhibition of the acetyl coenzyme-A carboxylase (ACCase) specific to this taxonomic group, and its secondary mode is by promotion of oxidative stress. FF is applied to S. anglica infestations in the intertidal zone, in proximity to seagrass meadows. Despite the potential for vital seagrass ecosystems to be exposed to FF, there is limited knowledge of any potential impacts. We investigated impacts of FPA on the endemic Australian seagrass, Zostera nigricaulis, measuring ACCase activity and parameters that reflect oxidative stress: photosynthetic performance, lipid peroxidation and photosynthetic pigment content. Seagrass was exposed to FF (0.01-10mgL-1 FPA and a control) for 7d, followed by a 7-d recovery in uncontaminated seawater. An enzyme assay demonstrated that FPA ≤10mgL-1 did not inhibit the activity of ACCase isolated from Z. nigricaulis, demonstrating that this seagrass is resistant to FFs primary mode of action. However, physiological impacts occurred following 7 days exposure to ≥0.1mgL-1 FPA, including up to a 72% reduction in photosynthetic pigment concentration. After 7-d recovery, photosynthetic pigment content improved in treatment plants; however, treated plants exhibited higher levels of lipid peroxidation. This study demonstrates that while Z. nigricaulis is resistant to FFs primary mode of action, significant physiological impacts occur following 7 days exposure to ≥0.1mgL-1 FPA. This study provides valuable information on the effects of FF on a non-target species that can better inform approaches to Spartina management in coastal seagrass ecosystems.