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.

Combined effects of organic or inorganic pollutants on soil microbial activities were investigated in field plots grown with four types of covering plants. It was derived from this study that combined effects were dependent not only on the type and dose of pollutants, addition of soda lime, plant type and season variation, but also on test parameters. When jointly added, higher doses of Cd, Cu, Pb, Zn and As caused significant inhibition. Addition of soda lime could even enhance inhibition. Joint effects of phenanthrene, MET (active ingredient: paclobutrazol) and 1,2,4-trichlorobenzene were not significant, and may be covered by other biotic or abiotic factors. Compared with other two parameters (respiration and microbial biomass), dehydrogenase activity appeared to be more sensitive for evaluating the toxicity of anthropogenic pollutants in soil. Soil samples collected in summer often had higher microbial activities than those in fall. The microbial activity in soil decreased with covering vegetation in the order alfalfa > pine > poplar and maize, albeit some exceptions were observed.

The Catalonian river sediments were found to be rich in keratinolytic fungi. The keratinolytic fungal populations showed clear seasonal changes in the river sediments. The main factors ‘regulating’ these populations in such habitat were temperature, dissolved oxygen concentration, pH, ammonium, nitrates, total fungal number, BOD₅, water poisons (cyanides, detergents, phenols), salinity and, presumably, strong insolation associated with low water levels. The last was probably of special importance in the deterioration of the fungal populations in the spring/summer season. A toxic effect on keratinolytic fungi in sediments was observed.Chrysosporium keratinophilum was found to be most resistant to industrial contaminants and salinity. Therefore, this species could be used as an indicator of water pollution.

In view of the toxic nature of Beryllium and its compounds the disposal of waste materials containing beryllium needs prior evaluation. The present study was undertaken to obtain information on the leachability and immobilisation of beryllium from solid waste red-mud generated in processing Beryl at the Beryllium Metal Plant at Vashi, New Bombay. The studies showed that 62% of the total beryllium in red-mud can be extracted by water by repeated leaching over a period of 445 d. The mixing of the waste material with cement and casting into cement blocks reduced the leachability of beryllium to 0.11% which got further reduced to 0.02% by thermal curing of cement blocks.

In June 1983 a whole-catchment liming experiment was conducted at Tjønnstrond, southernmost Norway, to test the utility of terrestrial liming as a technique to restore fish populations in remote lakes with short water-retention times. Tjønnstrond consists of 2 small ponds of 3.0 and 1.5 ha in area which drain a 25-ha catchment. The area is located at about 650–700 meters above sea-level in sparse and unproductive forests of spruce, pine and birch with abundant peatlands. A dose of 3 ton/ha of powdered limestone were spread by helicopter to the terrestrial area. No limestone was added to the ponds themselves. The ponds were subsequently stocked with brown and brook trout.Liming caused large and immediate changes in surface water chemistry; pH increased from 4.5 to 7.0, Ca increased from 40 to 200μeq/L, ANC increased from −30 to +70μeq/L, and reactive-Al decreased from about 10 to 3μmol/L. During the subsequent 11 years the chemical composition of runoff has decreased gradually back towards the acidic pre-treatment situation. The major trends in concentrations of runoff Ca, ANC, pH, Al and NO₃ in runoff are all well simulated by the acidification model MAGIC. Neither the measured data nor the MAGIC simulations indicate significant changes in any other major ion as a result of liming.The soils at Tjønnstrond in 1992 contained significantly higher amounts of exchangeable Ca relative to those at the untreated reference catchment Storgama. In 1992 about 75% of the added Ca remains in the soil as exchangeable Ca, 15% has been lost in runoff, and 10% is unaccounted for.The whole-catchment liming experiment at Tjønnstrond clearly demonstrates that this liming technique produces a long-term stable and favourable water quality for fish. Brown trout in both ponds in 1994 have good condition factors, which indicate that the fish are not stressed by marginal water quality due to re-acidification. The water quality is still adequate after 11 years and >20 water renewals. Concentrations of H⁺ and inorganic Al have gradually increased and approach levels toxic to trout, but the toxicity of these are offset by the continued elevated Ca concentrations. Reduced sulphate deposition during the last 4 years (1990–94) has also helped to slow and even reverse the rate of reacidification. The experiment at Tjønnstrond demonstrates that for this type of upland, remote terrain typical of large areas of southern Norway, terrestrial liming offers a suitable mitigation technique for treating acidified surface waters with short retention times.

The equilibrium partitioning theory may be used to describe the partitioning of nonionic organic chemicals between water, sediment, and aquatic biota. This paradigm was employed to compare the relative magnitudes of organic carbon-normalized sediment-quality criteria that are intended to protect either benthic organisms from the direct toxic effects of sediment-associated chemicals or humans from the indirect health effects posed by the ingestion of contaminated aquatic animals. Comparison of calculated sediment-quality criteria for a variety of hydrophobic chemicals suggests that human health-based end points often result in more restrictive criteria than aquatic effects-based values. Review of published field data indicates that the equilibrium partitioning paradigm may, depending on contaminant class, either over- or underestimate the extent to which sediment-associated contaminations are bioaccumulated. Despite the limitations of adopting this simple theory for criteria development, calculations reveal that regulatory decisions involving sediments contaminated with such chemicals may be dictated by human health concerns if current risk assessment methodologies are applied.

Induction of ethoxyresorufin-O-deethylase (EROD) activity and porphyrin accumulation shows different structure-activity relationships for different polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD). Interactions between the two responses can strongly influence the induction and activity of EROD. The results support the conclusion that there are non-additive interactions between nondioxin-like PCBs and dioxin-like compounds. The interaction between EROD activity and the porphyrin biosynthesis makes the prerequisite of additivity in the toxic equivalency factor concept for environmental mixtures highly spurious. Inhibition of EROD activity caused by nondioxin-like compounds could have a significant impact on the value of EROD activity as a biomarker in the present methods of risk assessment for these compounds.