Présentations Colloques

Oral Presentation
8.09
Session 8.09: Hydrogeoecology: a focus on groundwater ecology
Galassi Diana M.p.
Towards an EQS assessment in groundwater bodies- ammonium contamination and response of groundwater copepods
As a result of agricultural practices and underpowered wastewater treatments, groundwater bodies frequently show ammonium (NH4+) concentrations exceeding EU and National Quality Standards. We investigated NH4+ contamination in 17 alluvial and 9 rocky aquifers of the Abruzzo region (central Italy) to highlight the associated biological risk for the groundwater copepods (Crustacea Copepoda) selected as the target group.**We used 10,000 groundwater samples withdrawn from 520 sites (bores and springs) from 2010 to 2014.**We found that NH4+ contamination involved 4% of the samples collected in the alluvial aquifers, with concentrations sometimes exceeding 10-100 times the Italian QS (0.5 mg L-1). Conversely, less than 1% of samples collected in the rocky aquifers showed NH4+ concentrations exceeding the national QS. This is consistent with the fact that alluvial aquifer outcrops are used for farming (80%), whereas outcrops of the rocky aquifers are mainly protected areas. The level of NH4+ contamination detected in 4% of the investigated alluvial aquifers is such as to affect development, longevity and gene expression of the epigean cyclopoid Eucyclops serrulatus, that is commonly found in groundwater habitats. Recent research in the hyporheic zone of the River Sagittario (central Italy) revealed a significantly sensitivity of copepod assemblages to 0.084 mg L-1 NH4+, that is to the lowest QS currently set at European level. This state of affairs suggests that the Italian QS of 0.5 mg L-1 may not protect groundwater ecosystems. Since copepods are a link between primary producers and higher consumers and represent the most abundant group in groundwater bodies, the effects of the ammonia-N pollution should be taken into greater consideration for the assessment of effective criteria towards the EQS evaluation, that is so far not considered at both national and European levels.**
Italy