Adam M. Wightwick

Effects of pesticides monitored with three sampling methods in 24 sites on macroinvertebrates and microorganisms.

Grab water samples, sediment samples, and 2,2,4-trimethylpentane passive samplers (TRIMPS) were used to determine the exposure to 97 pesticides in 24 southeast Australian stream sites over 5 months. Macroinvertebrate communities and selected microorganisms (bacteria, flagellates, ciliates, amoebas, nematodes, and gastrotrichs) were sampled to detect relationships with pesticide toxicity. Sediment samples had the highest estimated toxicities in terms of toxic units (TU) for Daphnia magna (TUDM) and for Selenastrum capricornutum (TUSC). The pesticide-selective SPEARpesticides and the general SIGNAL index for macroinvertebrates exhibited negative linear relationships (r(2) = 0.67 and 0.36, respectively) with pesticide contamination in terms of log maximum TUDM (log mTUDM), suggesting macroinvertebrate community change due to pesticide exposure. Pesticide contamination was the only measured variable explaining variation in ecological quality. Variation in the densities of several microbial groups was best explained by environmental variables other than log TUs. The log mTUDM values derived from sediment concentrations were most important to establish a link with effects on macroinvertebrates, whereas log mTUDM of grab water samples had only minor contribution. Current-use insecticides and fungicides can affect macroinvertebrate communities and monitoring of sediment and continuous water sampling is needed to detect these effects.

Copper Fungicide Residues in Australian Vineyard Soils

Copper (Cu) concentrations were measured in Australian vineyard soils to assess the extent and magnitude of Cu accumulation resulting from the use of Cu-based fungicides and to indicate the likely risks to long-term soil fertility. Soil samples were collected from 98 vineyards across 10 grape-growing regions of Australia and analyzed for total Cu concentrations. Ninety-six percent of vineyards surveyed had elevated Cu concentrations in soil compared to the background Cu concentrations in nearby soil in its native state. Concentrations of total B, Co, Cr, Pb, and Zn were similar to background concentrations and below reported toxicity guideline values. Cu concentrations in Australian vineyard soils were generally much lower (6-150 mg kg (-1)) than those reported in the soils of vineyards in parts of Europe (i.e., 130-1280 mg kg (-1)). Concentrations of total Cu were generally below those concentrations reported to cause lethal effects to soil invertebrates; however, Cu exceeded concentrations known to cause sublethal effects (i.e., inhibit growth, affect reproduction, induce avoidance behavior) to those (or related) invertebrates.

Environmental Risks of Fungicides Used in Horticultural Production Systems

Adam Wightwick1,2,3, Robert Walters3, Graeme Allinson3,4, Suzanne Reichman5, and Neal Menzies1,2 1The University of Queensland 2Co-operative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) 3Department of Primary Industries, Victoria 4Victorian Centre for Aquatic Pollution Identification and Management (CAPIM) 5Royal Melbourne Institute of Technology (RMIT) University Australia

Inter-regional variability in environmental availability of fungicide derived copper in vineyard soils: an Australian case study.

This study determined the environmental availability of copper (Cu) in Australian vineyard soils contaminated with fungicide derived Cu residues, and investigated the soil characteristics correlated with differences in Cu availability between regions. Concentrations of 0.01 M calcium chloride extractable Cu, measured in surface soils collected from 98 vineyards in 10 different grape-growing regions of Australia, ranged from <0.1 to 0.94 mg/kg and accounted for 0.10-1.03% of the total Cu concentrations in the soils. Differences in the calcium chloride extractable Cu concentrations were related to the total Cu concentration and soil properties, including pH, clay, exchangeable K, silt, and calcium carbonate. The information generated from this study may prove useful in devising strategies to reduce the availability and toxicity of Cu in agricultural soils.

Effect of increasing salinity on the acute toxicity of a commercial endosulfan formulation to the bdelloid rotifer Philodina acuticornis odiosa

Pesticides, such as endosulfan, can enter surface waters such as lakes and rivers, potentially posing an ecological risk. Rotifers are a dominant zooplankton species in many inland freshwater lakes in Australia; such lakes can also experience increased salinities. Acute toxicity tests (24 h) were conducted to determine the toxicity of a commercial formaulation of endosulfan to the freshwater rotifer Philodina sp. and to investigate the influence of increasing salinity on endosulfan toxicity. Rotifers were found to be relatively tolerant to endosulfan with an EC50 of 1.75 mg L−1 (a.i.), with results also suggesting that there are no interactive effects of salinity on endosulfan toxicity.

Pesticide and trace metals in surface waters and sediments of rivers entering the Corner Inlet Marine National Park, Victoria, Australia

Water and sediment samples were collected from up to 17 sites in waterways entering the Corner Inlet Marine National Park monthly between November 2009 and April 2010, with the Chemcatcher passive sampler system deployed at these sites in November 2009 and March 2010. Trace metal concentrations were low, with none occurring at concentrations with the potential for adverse ecological effects. The agrochemical residues data showed the presence of a small number of pesticides at very low concentration (ng/L) in the surface waters of streams entering the Corner Inlet, and as widespread, but still limited contamination of sediments. Concentrations of pesticides detected were relatively low and several orders of magnitude below reported ecotoxicological effect and hazardous concentration values. The low levels of pesticides detected in this study indicate that agricultural industries were responsible agrochemical users. This research project is a rarity in aligning both agrochemical usage data obtained from chemical resellers in the target catchment with residue analysis of environmental samples. Based on frequency of detection and concentrations, prometryn is the priority chemical of concern for both the water and sediments studied, but this chemical was not listed in reseller data. Consequently, the risks may be greater than the field data would suggest, and priorities for monitoring different since some commonly used herbicides (such as glyphosate, phenoxy acid herbicides, and sulfonyl urea herbicides) were not screened. Therefore, researchers, academia, industry, and government need to identify ways to achieve a more coordinated land use approach for obtaining information on the use of chemicals in a catchment, their presence in waterways, and the longer term performance of chemicals, particularly where they are used multiple times in a year.

Use of reference soils in determinations of 0.01 m calcium chloride available metals

There are few readily available standard reference soils for which 0.01 M calcium chloride (CaCl2) soil extraction available metals data are available. This study assessed the ease with which new available metals data could be generated for reference soils. Data on 0.01 M CaCl2 available elements for four reference soils from the Wageningen Evaluating Programs for Analytical Laboratories and three reference soils from the Australasian Soil and Plant Analysis Council proficiency testing program are presented. It is difficult to generate new 0.01 M CaCl2 available metal values for standard reference soils, because trace element concentrations are low and measurements have relatively high variability. We suggest that laboratories can use reference soils as quality control samples in the analysis of 0.01 M CaCl2 available metals by reporting recoveries for major elements (e.g., potassium [K], magnesium [Mg], and sodium [Na], for which reference values are of high reliability) to provide assurance of acceptable extraction efficiency.

Industry Wide Risk Assessment: A Case Study of Cu in Australian Vineyard Soils

There are concerns over the environmental risks posed by Cu-based fungicide use, and there is community and regulatory pressure on viticultural industries to restrict the use of Cu-based fungicides. This study assesses the relative environmental risks posed by Cu-based and alternative synthetic organic fungicide compounds used in Australian vineyards, giving particular consideration to their adverse effects on soil microbial activity and how risks vary across different viticultural regions. The study was guided by key steps in the ecological risk assessment framework to analyse the risks of Cu-based fungicides towards soil organisms and involved four key steps: (1) problem formulation, (2) analysis (characterise exposure and effects), (3) risk characterisation and (4) risk assessment. There is evidence of a build-up of Cu-based fungicide residues in Australian vineyard soils, although this has occurred over many years, thus allowing the availability of Cu in the soil to be attenuated over time due to aging processes. On the whole, it appears that Cu-based fungicide residues are currently unlikely to pose a significant risk to soil organisms in Australian vineyard soils. However, there are indicators that continued applications of Cu-based fungicides may well have implications on the use of impacted land for sustainable agricultural production. Further detailed studies are required to enable a more definitive characterisation of the risks posed by Cu-based fungicide residues, such as establishing a clearer link between the laboratory and agricultural settings, investigating effects on other indicators of microbial activity and biodiversity and understanding the resilience of soil microbes to additional stressors. The challenge for agricultural industries and governments, both in Australia and globally, is to formulate appropriate plans to reduce the risks associated with Cu-based fungicide use. Further research is required to consider the relative risks of a wide range of alternative fungicide compounds to ensure that they pose a lower environmental risk than the Cu-based fungicides they may replace.

Utilization of a new bdelloid rotifer (Philodina acuticornis odiosa) assay to evaluate the effect of salinity on the toxicity of chlorothalonil

Acute (24 h) toxicity tests were conducted to determine the toxicity of the fungicide chlorothalonil towards the freshwater bdelloid rotifer (Philodina acuticornis odiosa). Since rotifers are the dominant zooplankton species in many inland freshwater lakes in Australia, the influence of salinity on chlorothalonil toxicty was also assessed. The rotifers used in this study appeared to be reasonably tolerant to changes in salinity, with little mortality observed at 3760 µS cm−1, increasing thereafter at higher salinity. The bdelloid rotifers were, however, found to be highly sensitive to chlorothalonil (24 h LC50, 3.2 µg L−1) with results also suggesting that as salinity increases, so does toxicity (e.g., 24 h LC50 at 5000 µS cm−1, 0.5 µg L−1).