Οικοτοξικότητα και επιδράσεις αγροτοβιομηχανικών αποβλήτων στη βιοποικιλότητα ρεόντων οικοσυστημάτων σε διαφορετικά βιολογικά επίπεδα οργάνωσης ; Ecotoxicity and effects of agro-industrial wastewaters to stream biodiversity at multiple levels of biological organisation

The significant expansion of the agricultural industry during the last decades has resulted to the increased production of organic wastes, such as olive mill and citrus processing wastewaters. Olive mill wastewater (OMW), one of the major and challenging pollutant in the Mediterranean countries, is the organic effluent generated during the extraction of olive oil, where huge quantities of organic wastes are produced within a short time-period (November – February). Citrus processing wastewater (CPW) is the organic effluent generated during the production of citrus juice from November to June. The effective treatment of both wastewaters, due to their enormous organic load and their toxic components, requires expensive and advanced technologies that many units lack. This usually results to the uncontrolled disposal of untreated or partially treated OMW and CPW in aquatic and terrestrial ecosystems that may pose serious risks to aquatic and terrestrial biota and subsequently to the health of the corresponding ecosystems. Despite the acknowledged high polluting capacity of olive mill and citrus processing wastewaters, their toxicity and effects to aquatic macroinvertebrates and to the ecological status of stream ecosystems remain up to date relatively unknown. The aims of this research was to: a) assess OMW and CPW toxicity on stream macroinvertebrates using acute toxicity bioassays (LC50-24hrs), b) evaluate the effects of sub-lethal concentrations of OMW and CPW at the biochemical level of the stream fauna, c) assess the spatial and temporal effects of OMW and CPW to stream macroinvertebrate abundance and assemblages and to the ecological status of stream ecosystems, and d) assess the effects of OMW pollution in different stream types (mountainous and lowland streams) and evaluate the self-purification potential of the particular streams. Since olive trees strongly follow a biennial cycle of growth and production, a two-year monitoring campaign was conducted in order to assess spatial and temporal responses of ...