DIAGNOSIS OF BORON, FLUORINE, LEAD, NICKEL AND ZINC TOXICITY IN CITRUS PLANTATIONS IN VILLARREAL, SPAIN

In the late 1980s, citrus plantations in the area of Villarreal (Spain ) showed injuries similar to those previously reported for boron and f luorine toxicity. The area was affected by the disposal of industrial wastewater, mainly from ceramic industries. Conjunctive uses of surfac e water, groundwater and wastewater for irrigation had taken place. A survey was conducted at 25 orchards to assess leaves and soil for thei r boron, fluorine, lead, nickel and zinc contents. Wastewater and grou ndwater were also analyzed to corroborate the presence of these pollut ants. The results showed that both boron and fluorine contents were gr eater than those reported as excess at the most part of the orchards i ncluded in the study. Heavy metals toxicity effects were not confirmed . Boron pollution was attributed to industrial wastewater spills and f luorine contamination from atmospheric pollution.