Loch fleet: liming to restore a brown trout fishery

This project has been successful in meeting its objectives in terms of demonstrating that catchment liming techniques can restore acidified waters to conditions suitable for fish populations for relatively long periods. This improvement in conditions has extended to the inlet stream, which provides vital fish spawning and nursery areas, which are difficult to treat effectively be other means in remote locations. The project has also provided an assessment of the effectiveness of differing rates and modes of lime application, which suggest that only quite restricted parts of a catchment require treatment. This not only maximizes the cost-effectiveness of the treatments, but also helps to minimize any side-effects on, for example, moorland vegetation. The biological monitoring programme at Loch Fleet has also provided an assessment of the overall ecological consequences of adding limestone to naturally acidic and calcium-deficient ecosystems.     

The effect of liming agricultural land on the chemistry and biology of the River Esk, north-west England

A land-use study indicated that a reduction in agricultural liming may have been a major factor in the development of acid episodes and consequent fish kills in the River Esk and River Duddon. A field study was carried out to determine whether the reintroduction of catchment liming in the Esk valley could ameliorate acid episodes and thus prevent fish kills. Lime was applied to areas which had been limed in the past, comprising 10% of the Esk catchment. Flow, pH, calcium, aluminium, total humic substances, conductivity and invertebrates were monitored before and after liming. The River Duddon was monitored as a reference. There was a general reduction of the acidity of both the River Esk and the River Duddon during the study period. This appeared to be controlled by rainwater chemistry. There was little evidence for a major effect of liming on water chemistry which suggests that the mortalities of salmonids in the early 1980s were not due to a reduction in agricultural liming.     

石灰对稻米吸收Cd的影响及施用风险的区域调查与田间实验

通过区域调查与田间实验相结合的方法探讨施用石灰对土壤-水稻系统镉(Cd)污染的控制效果和潜在风险.区域调查结果显示,研究区稻米Cd超标率高达72.6％;石灰处理可降低21.1％的土壤Cd活性和9.7％的稻米Cd超标率,并小幅提升土壤pH,但存在不确定性.田间实验结果显示,经石灰处理后,稻米Cd含量从0.26 mg·kg...     

The response of Lemna trisulca L. to cadmium

Lemna trisulca was grown, using aseptic culture techniques in a filter-sterilized medium, a portion of which was replaced regularly during experiments. L. trisulca responded to the addition of 0.64 microM Cd with a reduction in multiplication rate (MR) 2 +/- 1 days after exposure. The internal Cd content reached 1000 +/- 140 microg Cd/g (dry wt) within 2 days exposure to 0.64 microM Cd. The final yield was reduced by an average of c.8% for each day of exposure to 0.64 microM Cd in a 14 day experiment. This implies that an equilibration period should be used for short-term bioassay tests before the effect of a toxicant is determined. Pretreating L. trisulca with 0.08 or 0.32 microM Cd for 6 weeks had no significant effect on MR or Cd uptake when plants were subsequently exposed to a range of Cd concentrations or grown in a control medium. This suggests that L. trisulca does not become acclimated to elevated Cd concentrations. The MR of L. trisulca fluctuated over a period of almost 600 days and the doubling time ranged from 1.6 to 2.4 days. This produced more than a fivefold difference in final yield in experiments of 14 days duration. The reduction in MR in response to 0.32 microM Cd during this same 600 days period averaged 24% with a coefficient of variation of 38%, and varied with the MR of control cultures. Fluctuations in the intrinsic growth rate and the effect of a toxicant on L. trisulca could potentially confound the assessment of toxicity and must be carefully considered when designing test protocols for aquatic plants.     

Improvement of breeding success of the moor frog (Rana arvalis) by liming of acid moorland pools and the consequences of liming for water chemistry and diatoms

Liming experiments with powdered limestone (grain size < 3 mm) were conducted in eight acid shallow moorland pools in the Tongerense Heide heathland area from February 1988 until November 1989. The effects on water chemistry, diatoms and fungal infection of the eggs of the moor frog were studied. After an initial treatment in March 1988, the pH increased from c. 4.0 to c. 5.0 in those pools which dried out in summer and to c. 6.0 in the permanent pools. Alkalinity increased from 0 to 20-200 microeq litre(-1) in temporary pools and from 0 to 300-500 microeq litre(-1) in permanent pools. As drying out of the pools caused reacidification, after refilling the temporary pools were relimed in March 1989. No significant changes were found in concentrations of phosphate and nitrogen compounds. Eunotia paludosa, which is characteristic for ologotrophic, very acid pools and bogs with a fluctuating water table, was the dominant diatom in the untreated pools. It was replaced by eutraphentic and saprophilous taxa, particularly in the permanent pools. Species from extremely soft waters, which are very sensitive to acidification, were found only occasionally in some samples from the treated permanent pools. After liming the proportion of infected moor frog eggs decreased from c. 95% in the untreated to c. 5% in the treated pools.     

Effect of liming on plant accumulation of cadmium under upland or flooded conditions

Liming a Cd-amended red earth (typical hapludalf) decreased plant shoot Cd content both in upland and in flooded conditions. The effect was due to the restriction of the total uptake of Cd from soil and the Cd transfer from roots to shoots following liming. Pot soil samples were sequentially extracted with 1 M ammonium acetate, 0.125 M Cu(II) acetate, and 1 m HNO3 to fractionate Cd into exchangeable, complexed, and acid-soluble forms. Results showed that soil flooding decreased exchangeable Cd and increased Cd in the complexed fraction. Liming also transferred Cd from exchangeable fraction to other lower available fractions depending on water regimes. With upland conditions, the Cd was transferred to the residual fraction, and to a lesser extent to the acid-soluble fraction, whereas in flooded soil the lost exchangeable Cd was recovered mainly in complexed fraction where the Cd was potentially more available for plants compared with that in residual and in acid-soluble fractions. Therefore, soil liming for controlling plant Cd uptake would be more favourable in upland rather than flooded conditions.     

Biofilm responses to marine fish farm wastes

The changes in the biofilm community due to organic matter enrichment, eutrophication and metal contamination derived from fish farming were studied. The biofilm biomass, polysaccharide content, trophic niche and element accumulation were quantified along an environmental gradient of fish farm wastes in two seasons. Biofilm structure and trophic diversity was influenced by seasonality as well as by the fish farm waste load. Fish farming enhanced the accumulation of organic carbon, nutrients, selenium and metals by the biofilm community. The accumulation pattern of these elements was similar regardless of the structure and trophic niche of the community. This suggests that the biofilm communities can be considered a reliable tool for assessing dissolved aquaculture wastes. Due to the ubiquity of biofilms and its wide range of consumers, its role as a sink of dissolved wastes may have important implications for the transfer of aquaculture wastes to higher trophic levels in coastal systems.     

Behavioral changes in fish exposed to phytoestrogens

We investigated the behavioral effects of exposure to waterborne phytoestrogens in male fighting fish, Betta splendens. Adult fish were exposed to a range of concentrations of genistein, equol, beta-sitosterol, and the positive control 17beta-estradiol. The following behaviors were measured: spontaneous swimming activity, latency to respond to a perceived intruder (mirror reflection), intensity of aggressive response toward a perceived intruder, probability of constructing a nest in the presence of a female, and the size of the nest constructed. We found few changes in spontaneous swimming activity, the latency to respond to the mirror, and nest size, and modest changes in the probability of constructing a nest. There were significant decreases, however, in the intensity of aggressive behavior toward the mirror following exposure to several concentrations, including environmentally relevant ones, of 17beta-estradiol, genistein, and equol. This suggests that phytoestrogen contamination has the potential to significantly affect the behavior of free-living fishes.     

Residues in fish exposed to sublethal doses of endosulfan and fish collected from cotton growing area

A one step extraction and cleanup procedure for determining endosulfan in fish was investigated. Minced Fish was mixed with trisodium citrate, disodium hydrogen orthophosphate and sodium sulphate into a dry powdery mixture, which was eluted through silicic acid and alumina with a mixture of dichloromethane and hexane. The eluate was concentrated and chromatographed on GLC using an EC detector without further cleanup. Three species of fresh water fish exposed to 0.7-16 micrograms/litre-1 technical grade endosulfan in tanks for various periods of time were found to concentrate both alpha and beta endosulfan and metabolise them to sulfate, diol, ether and lactone. Fish collected from Gwydir River in the cotton growing area in summer (Dec. 1986-Feb. 1987) were found to contain endosulfan residues suggesting endosulfan is quite stable in the environment and can cause residues.     

Changes in primary productivity associated with liming and reacidification of an Adirondack lake

The addition of calcium carbonate to a clearwater acidic lake had a significant effect on phytoplankton abundance and on the biomass-specific rate of production. Chlorophyll concentrations and productivity: biomass ratios were strongly correlated with changes in lake acidity associated with liming and reacidification (r2=0.89 and 0.73, respectively). Summer mean chlorophyll increased by 0.9 mg m(-3) for each unit increase in lake pH, whereas productivity:biomass ratios decreased from > 2 to < 1 with an increase in pH from 5.5 to 7.0. Higher phytoplankton standing crops after liming were attributed to lower grazing rates following the decline of the dominant zooplankton taxa. A model relating biomass-specific productivity to incident light levels was found to be useful in interpreting treatment effects on productivity. Incident light and biomass (based on chlorophyll) accounted for 81% of the variability in productivity at the treated site. Comparisons of photosynthesis-irradiance curves indicated that the maximum photosynthetic capacity was higher following the watershed liming, compared to data collected after lake liming and during reacidification.     

Biochemical stress response in freshwater fish Channa punctatus induced by aqueous extracts of Euphorbia tirucalli plant

Piscicidal activities of aqueous extracts of Euphorbia tirucalli were very well established, but their ultimate mode of action on fish metabolism was not yet known. Exposure of fishes over 24h or 96h to sub-lethal doses (40% and 80% of LC(50)) of aqueous extract of E. tirucalli stem-bark and latex, significantly (P<0.05) altered the level of total protein, total free amino acids, nucleic acids, glycogen, pyruvate, lactate and activity of protease, alanine aminotransferase, aspartate aminotransferase, acetylcholinesterase and cytochrome oxidase enzyme in liver and muscle tissues of freshwater fish Channa punctatus. The alterations in all these biochemical parameters were significantly (P<0.05) time- and dose-dependent. After 7d of withdrawal of treatment of 80% of LC(50) of E. tirucalli extracts shows that there was a partial recovery in the levels of glycogen but nearly complete recovery in total protein, total free amino acids, pyruvate, lactate, nucleic acids level and activity of protease, aspartate aminotransferase, alanine aminotransferase, acetylcholinesterase and cytochrome oxidase enzyme in both the tissues of fish. Thus aqueous extracts of E. tirucalli adversely affect respiratory pathway of fish and cause energy crisis during stress by suppressing ATP production. The reversibility of the action of the aqueous extracts would be an additional advantage in their use.     

The integrated biomarker response revisited: optimization to avoid misuse

The growing need to evaluate the quality of aquatic ecosystems led to the development of numerous monitoring tools. Among them, the development of biomarker-based procedures, that combine precocity and relevance, is recommended. However, multi-biomarker approaches are often hard to interpret, and produce results that are not easy to integrate in the environmental policies framework. Integrative index have been developed, and one of the most used is the integrated biomarker response (IBR). However, an analysis of available literature demonstrated that the IBR suffers from a frequent misuse and a bias in its calculation. Then, we propose here a new calculation method based on both a more simple formula and a permutation procedure. Together, these improvements should rightly avoid the misuse and bias that were recorded. Additionally, a case study illustrates how the new procedure enabled to perform a reliable classification of site along a pollution gradient based on biomarker responses used in the IBR calculations.     

Sorption of 3,4-dichloroaniline on four contrasting Greek agricultural soils and the effect of liming

Sorption of 3,4-dichloroaniline (3,4-DCA) on four typical Greek agricultural soils, with distinct texture, organic matter content and cation exchange capacities, was compared by using sorption isotherms and the parameters calculated from the fitted Freundlich equations. The sorption process of 3,4-DCA to the soil was completed within 48–72 h. The 3,4-DCA sorption on all soils was well described by the Freundlich equation and all sorption isotherms were of the L-type. The sandy clay loam soil with the highest organic matter content and a slightly acidic pH was the most sorptive, whereas the two other soil types, a high organic matter and neutral pH clay and a low organic matter and acidic loam, had an intermediate sorption capacity. A typical calcareous soil with low organic matter had the lowest sorption capacity which was only slightly higher than that of river sand. The 3,4-DCA sorption correlated best to soil organic matter content and not to clay content or cation exchange capacity, indicating the primary role of organic matter. The distribution coefficient (K _d) decreased with increasing initial 3,4-DCA concentration and the reduction was most pronounced with the highly sorptive sandy clay loam soil, suggesting that the available sorption sites of the soils are not unlimited. Liming of the two acidic soils (the sandy clay loam and the loam) raised their pH (from 6.2 and 5.3, respectively) to 7.8 and reduced their sorption capacity by about 50 %, indicating that soil pH may be the second in importance factor (after organic matter) determining 3,4-DCA sorption.     

Recovery of acid-sensitive species of ephemeroptera, plecoptera and trichoptera in river audna after liming

River Audna has been continuously limed on a full scale basis since 1985. Monitoring of benthic invertebrates of the river showed that the fauna was dominated by acid-tolerant species before liming and during the first year after the start of the treatment. Moderately acid-sensitive species, like Diura nanseni, Isoperla grammatica and Hydropsyche siltalia were found only in small numbers in a few localities in this period. In autumn 1987, the first appearance of the highly acid-sensitive mayfly Baetis rhodani was recorded at two stations in the main river. During the following years, this species colonized other localities and several other sensitive invertebrates, such as Heptagenia sulphurea, Caenis horaria, Hydropsyche pellucidula and Lepidostoma hirtum were also recorded. The change in faunal composition was highly significant compared to unlimed reference stations.     

Sorption of 3,4-dichloroaniline on four contrasting Greek agricultural soils and the effect of liming

Sorption of 3,4-dichloroaniline (3,4-DCA) on four typical Greek agricultural soils, with distinct texture, organic matter content and cation exchange capacities, was compared by using sorption isotherms and the parameters calculated from the fitted Freundlich equations. The sorption process of 3,4-DCA to the soil was completed within 48-72 h. The 3,4-DCA sorption on all soils was well described by the Freundlich equation and all sorption isotherms were of the L-type. The sandy clay loam soil with the highest organic matter content and a slightly acidic pH was the most sorptive, whereas the two other soil types, a high organic matter and neutral pH clay and a low organic matter and acidic loam, had an intermediate sorption capacity. A typical calcareous soil with low organic matter had the lowest sorption capacity which was only slightly higher than that of river sand. The 3,4-DCA sorption correlated best to soil organic matter content and not to clay content or cation exchange capacity, indicating the primary role of organic matter. The distribution coefficient (K(d)) decreased with increasing initial 3,4-DCA concentration and the reduction was most pronounced with the highly sorptive sandy clay loam soil, suggesting that the available sorption sites of the soils are not unlimited. Liming of the two acidic soils (the sandy clay loam and the loam) raised their pH (from 6.2 and 5.3, respectively) to 7.8 and reduced their sorption capacity by about 50 %, indicating that soil pH may be the second in importance factor (after organic matter) determining 3,4-DCA sorption.