title: Evaluation of olive oil mill wastewater toxicity on spinach.
abstract: OBJECTIVE
  Olive oil mill wastewater (OMW), a by-product of the olive oil extraction process, is annually produced in huge amounts in olive-growing areas and represents a significant environmental problem in Mediterranean areas. We studied the impact of OMW dilutions (1:20 and 1:10) on spinach plants in order to evaluate OMW dilutions as a low-cost alternative method for the disposal of this waste.
  
  
  METHODS
  The effects of OMW dilutions were evaluated on seed germination, shoot and root elongation, biomass production, nutrient uptake and translocation, ascorbic acid content, polyphenols, photosynthetic pigments, and photosynthetic performance of spinach.
  
  
  RESULTS
  Plant biomass was more affected than plant height and total chlorophyll; carotenoid and ascorbic acid content progressively decreased with decreasing OMW dilution. Exposure to both OMW dilutions resulted in overaccumulation of total polyphenols, which were negatively correlated to plant biomass and nutrients. Nutrient (Fe, Ca, and Mg) content was insufficient leading to reduced growth. Water use efficiency decreased mainly due to decreased CO(2) assimilation rate rather than to a decline of transpiration rate. Disturbances in photosystem II (PSII) photochemical efficiency could be better envisaged by the ratio between variable fluorescence and initial fluorescence (Fv/Fo), which showed much greater amplitude than the maximal photochemical efficiency of PSII photochemistry (Fv/Fm).
  
  
  CONCLUSIONS
  From the data obtained, it is suggested that 1:20 OMW dilutions are still phytotoxic and that higher OMW dilutions should be used in order to use this waste for the irrigation of spinach plants.
authors.affiliation: Institute of Food Technology, National Agricultural Research Foundation, 14123 Lycovrissi, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Asfi
authors.forename: Georgia
authors.initials: G
authors.lastname: Ouzounidou
authors.forename: Michael
authors.initials: M
authors.lastname: Moustakas
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis; D002734:Chlorophyll / Q000032:analysis; D005525:Food-Processing Industry; D007220:Industrial Waste / Q000009:adverse effects; D000069463:Olive Oil; D018515:Plant Leaves / Q000737:chemistry; D010938:Plant Oils; D059808:Polyphenols / Q000032:analysis; D018724:Spinacia oleracea / Q000737:chemistry / Q000187:drug effects* / Q000254:growth & development; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000494:pharmacology*
chemical_list: D007220:Industrial Waste; D000069463:Olive Oil; D010938:Plant Oils; D059808:Polyphenols; D014874:Water Pollutants, Chemical; D002734:Chlorophyll; D001205:Ascorbic Acid