Valentina Pieri

OSTRACOD DENSITY, RICHNESS AND COMMUNITY COMPOSITION FOR THE MONITORING OF RESIDUAL WASTEWATER DISCHARGE (STUDY AT RIVER LEDRA) (ENG only)

(ENG only)

Ostracoda (Crustacea) as indicators of surface water quality: a case study from the Ledra River basin (NE Italy)

Wastewater discharges associated with urbanisations, farming activities and industry may dramatically reduce the ecological health of river ecosystems. Their efficiency is usually assessed through monitoring of the physical and chemical environment near the discharge point. However, discontinuous monitoring of the abiotic environment may fail to detect periodic malfunctioning and do not recognize indirect effects on the ecosystem.

We assessed the potential of an alternative approach to assess the impact of wastewater discharges, based on the monitoring of ostracod density, richness and community composition. We linked community structure of Recent non marine ostracods (Crustacea: Ostracoda) with physical-chemical and microbiological parameters at stations before and after wastewater treatment plants in a river basin.

• In particular, the objectives of the present research were to investigate:
• the water quality of the Ledra river basin
• the efficiency of a series of WWTPs in the study area by monitoring changes in abiotic (physical and chemical water parameters) and biotic (ostracod species composition, density and richness) environment.
• the potential of using ostracods as indicators of water quality in small lotic systems.

The study area covers all the Ledra River basin (21 km long), localized in Friuli Venezia Giulia (NE Italy). This basin includes a variety of habitat typologies as lowland springs, channels and streams, with different levels of anthropogenic impact.

The results indicate that monitoring ostracods is a potentially valuable approach, for two reasons. Communities appeared to be well differentiated even in the small spatial area of this study, indicating that they can provide sufficient resolution to pick up even minor impacts. Secondly, despite the seasonal succession in species composition, spatial differentiation was consistent over time, suggesting that ostracods provide a time-integrated picture of the water quality.

On the other hand, discharges did not affect the physical or chemical environment based on the repeated snapshot samplings. These results suggest that the monitoring of ostracods provides an integrated picture of the water quality of a lotic system, even on a very local scale. Work in progress is:

• assessing the interaction between the ostracod community composition and the presence of metals in surface waters in Ledra river basin (Udine);
• developing, in collaboration with the Royal Belgian Institute of Natural Sciences (Brussels), a molecular phylogenetic framework to allow an alternative approach to assess the impact of residual of wastewater discharges, based on the monitoring of ostracod density, richness and community composition (pilot study at the basin of the River Ledra);
• developing a standard procedure to monitor ostracod DNA for use in a residual pollution environment. The aim of this research can further contribute to recognizing indirect effects on the ecosystems by residual and emerging pollutants coming from wastewater treatment plants to the surface waters. It can also be a next step to a new kind of collaboration between environmental engineers and ecologists.
• Further research is planning on the pollution by treatment plants and run-offs within the pilot LEDRA basin.

• V. Pieri, J. Vandekerkhove, D. Goi, “Freshwater Ostracoda (Crustacea) as indicators for surface water quality: a case study from Ledra river basin (NE Italy)”, Proceedings of 16th International Symposium on Ostracoda, João Carlos Coimbra Ed., 23-30 July 2009, Brasìlia, Brazil (2009).
• V. Pieri, A. Daici, M. Simonetti, D. Goi, “ Monitoraggio della qualità delle acque del bacino del fiume Ledra”, IAIngegneria Ambientale, (2010), XXXIX (5):241-248.
• V. Pieri, J. Vandekerkhove, D. Goi, “Ostracoda (Crustacea) as indicators for surface water quality: a case study from the Ledra River basin (NE Italy)”. Hydrobiologia (2012), 688:25-35, DOI 10.1007/s10750-010-0568-1.
• V. Pieri, J. Vandekerkhove, D. Goi,. Ostracoda (Crustacea) as indicators for surface water quality: a case study from the Ledra River basin (NE Italy). In: VI Convegno degli Ostracologi Italiani. Trieste:EUT (2012), ISBN: 978-88-8303-375-9.