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

The foliage contents of Sₜₒₜₐₗ and Nₜₒₜₐₗ were determined in 405 Permanent monitoring plots in four National Parks and sixteen Landscape Protection Areas and were compared with 1483 Permanent monitoring plots on Slovakia. The foliage content of S ranged from 0.72 to 6.77 g kg⁻¹ in hardwoods and from 0.98 to 4.3 g kg⁻¹ in softwoods. A critical increase was determined in one National Park and in four Landscape Protection Areas. The foliage content of N ranged from 9.7 to 48.7 g kg⁻¹ in softwoods, and from 7.8 to 51.4 g kg⁻¹ in hardwoods. An insufficient level of N was determined in one Landscape Protection Area and a critical increase in four Landscape Protection Areas. The sulphur to nitrogen ratio ranged from 0.08 to 0.176 in softwoods, and from 0.078 to 0.253 in hardwoods. The foliage surface on hitherto explored four National Parks and sixteen Landscape Protection Areas in network 4×4 km was covered by all categories of rigid fallout particles. Fly-ash from coal combustion were observed each of National Parks and Landscape Protection Areas by scanning electron microscopy. Mycelia and spore, mineral matters, sand and soil particles were present on all National Parks and Landscape Protection Areas. Particles derived from aluminium production were observed at three Landscape Protection Areas. Particles derived from cement production and from lime works were observed at two National Parks and six Landscape Protection Areas. Particles derived from ferrous metals industry were observed at each of National Parks and Landscape Protection Areas and particles typical for other technologies were present in three of National Parks and twelve Landscape Protection Areas.