Why investigate sediments when assessing aquatic ecosystems David Sharley Simon Sharp and Dan MacMahon CAPIM Research Summit August 2016

Sediments in aquatic ecosystems Sediments provide habitat, sources of food, nutrient cycling and microbial decomposition Riparian habitat Healthy Ecosystems Sediment quality Water quality Hydrology Biodiversity Instream habitat

Sediments are sinks for pollutants Sediments strongly bind many pollutants can carry high pollutant load Depend on binding ability differs between compounds and depends on organic content of sediment Organic contaminants tend to bind more strongly to sediments

Sediments as a pollution monitoring tool Sediments can accumulate pollutants over time Provide opportunities to develop long-term trends in pollution Identify pollution Hotspots along waterways Develop sediment-based ecotoxicity assessment tools

Sediment pollution trends

Heavy metal pollution

2010-2014

Sharley, D. J. , Sharp, S. M. , Bourgues, S. , Pettigrove, V. 2016 Sharley, D.J., Sharp, S.M., Bourgues, S., Pettigrove, V. 2016. Detecting long-term temporal trends in sediment-bound trace metals from urbanised catchments. Environmental Pollution In Press.

Population change Sharley, D.J., Sharp, S.M., Bourgues, S., Pettigrove, V. 2016. Detecting long-term temporal trends in sediment-bound trace metals from urbanised catchments. Environmental Pollution In Press.

Assessing catchments using a multiple lines of evidence approach

Measuring ecological condition Benthic structure Chemistry Habitat hydrology More specific / causal Molecular, Biochemical Community Population Individual Physiological Ecosystem More ecologically relevant Toxicology Isolating chemistry Impacts on biota Biomarkers Links to chemical exposure to biota

Metals (PECQ) Herbicides Insecticides Fungicides

Amphipod toxicity results Q. Lang Amphipod toxicity results Termite protection applied in new housing developments is the likely source of bifenthrin at this site

Chironomus tepperi survival Chinamens Creek Chironomus tepperi development (emergence) Chinamens Creek

Synthetic pyrethroids Emerging urban issue Highly toxic to insects and fish but low mammalian toxicity Hydrophobic (stick to sediments) Widespread use Domestic flea powders Domestic garden pest control Infrastructure termite control (new urban developments)

Using sediment monitoring data to identify catchment issues Prioritise management actions Chinaman Creek

Chinaman’s Creek sediment Sampling

Further sediment sampling

Further drain investigations

Macroinvertebrate sampling and identification Acknowledgements funding and support Melbourne Water EPA Victoria DEWLP Local Government School of BioSciences - Unimelb Everyone at CAPIM Field collections Ecotoxicology Macroinvertebrate sampling and identification