Effect of water extract of the bark of Buchanania lanzan linn. on behaviour and chromatophores of a fresh water fish,Labeo rohita

Fish exposed to 150 ppm and 250 ppm doses saparately, showed eratic swimming with hyper-excitability, spiralling, convulsion and mortality. However at 350 ppm dose fish became lethargic and steady at the bottom of aquarium. This behaviour appears to be due to sedative effects of fish implicating the phychoactive nature of the plant B. Ianzan. At 150 ppm to 350 ppm doses, fish scale changed from reticulate to punctate chromatophores; and treated fish when transferred to fresh water, were slowly regained to normal behaviour after 96 h exposure. Hence doses regaining from 150 ppm to 350 ppm is considered to be psychoative in nature. In higher doses 450 ppm and 550 ppm fish could survive only 76 h and 4.30 h respectively and then died indicating toxicity of plant for the said doses. It is found that scale present on its body is most suitable test system for the study of psychoactivity and toxicity of plant extracts on fish, Labeo rohita.     

Ni and Cu migration and accumulation in forest ecosystems on the Kola Peninsula

Biogeochemical cycles of Ni and Cu in pine forests on the northern tree line (Kola peninsula) in the background and industry-disturbed areas have been investigated. Total, bio-available and exchangeable concentrations of Ni and Cu in the soil, atmospheric Ni and Cu fluxes and soil water migration, and metal uptake by plants are considered. In the polluted area, forest ecosystems are seen as biogeochemical barriers which may attenuate intensity of Ni and Cu migration down the soil profile. A quantitative assessment is given of the role of dominating forest plants and soil horizons as barriers to heavy metal fluxes.     

Critical remarks on the use of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) for monitoring of airborne pollution

Duplicate samples of the two terrestrial moss species Hylocomium splendens and Pleurozium schreberi, which are widely used to monitor airborne heavy metal pollution, have been collected from eight catchments spread over a 1,500,000 km2 area in northern Europe. These were analysed for a total of 38 elements by inductively coupled plasma-mass spectrometry, inductively coupled plasma-atomic emission spectrometry and cold vapour-atomic absorption spectometry techniques. Results show that the moss species can be combined without interspecies calibration for regional mapping purposes. For the majority of elements the observed within-catchment variation is large--big composite samples over a large area should thus be collected when moss is to be used for monitoring purposes. For the majority of elements the input of dust governs moss chemistry. For a reliable 'contamination' signal over a sizeable area a major source is needed. Some elements show a dependence on climate/vegetation zone. In coastal areas the input of marine aerosols will alter the chemical signal obtained from moss samples.     

Anthropogenic radionuclides in the Japan Sea: their distributions and transport processes

The anthropogenic radionuclides, (90)Sr, (137)Cs and (239+240)Pu, were measured in the water column of the Japan Sea/East Sea during 1997-2000. The vertical profiles of radionuclide concentrations showed: exponential decrease with depth for (90)Sr and (137)Cs, and surface minimum/subsurface maximum for (239+240)Pu. These results do not differ substantially from results reported previously. The area-averaged concentrations of radionuclides in the Japan Sea are higher than those found in the Northwest Pacific Ocean below surface layer showing the accumulation of the radionuclides in the deep waters in the Japan Sea. Concerning spatial distributions, the area of high (137)Cs inventory extends from the Japan Basin into the Yamato Basin. It is suggested that wintertime convection of water, occurring mainly in the Japan Basin, causes the radionuclides to sink. The nuclides then advect into the Yamato Basin after detouring around the Yamato Rise.     

Photolysis of atrazine and ametryne herbicides in Barbados sugar cane plantation soils and water

The photodegradation kinetics of atrazine (2-chloro-6-(ethylamino)-4-isopropylamino-1,3,5-triazine) and ametryne (2-methylthio-4-ethylamino-6-isopropylamino-s-triazine), in fresh and coastal salt water from Barbados, were measured under irradiation with artificial solar and UV254-radiation. The first-order rate constants were greater for ametryne than for atrazine, and the rates were reduced in seawater relative to fresh water, and in soil slurries relative to fresh water. However, rates were accelerated in the presence of iron(III) at pH 3 due to photo-Fenton type processes. This rate enhancement was reduced at ambient pH values (pH 7-7.5) representative of surface water in Barbados. These results have important implications for the relative persistence of these contaminants in aquatic environments in tropical areas.     

Endosulfan transport: I. Integrative assessment of airborne and waterborne pathways

To reduce endosulfan (C9H6O3Cl6S; 6,7,8,9,10,10-hexachloro-1,5, 5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide) contamination in rivers and waterways, it is important to know the relative significances of airborne transport pathways (including spray drift, vapor transport, and dust transport) and waterborne transport pathways (including overland and stream runoff). This work uses an integrated modeling approach to assess the absolute and relative contributions of these pathways to riverine endosulfan concentrations. The modeling framework involves two parts: a set of simple models for each transport pathway, and a model for the physical and chemical processes acting on endosulfan in river water. An averaging process is used to calculate the effects of transport pathways at the regional scale. The results show that spray drift, vapor transport, and runoff are all significant pathways. Dust transport is found to be insignificant. Spray drift and vapor transport both contribute low-level but nearly continuous inputs to the riverine endosulfan load during spraying season in a large cotton (Gossypium hirsutum L.)-growing area, whereas runoff provides occasional but higher inputs. These findings are supported by broad agreement between model predictions and observed typical riverine endosulfan concentrations in two rivers.     

Sorption of polycyclic aromatic compounds to humic and fulvic acid HPLC column materials

Two different humic acids (HA) and a fulvic acid (FA) were chemically immobilized to a high performance liquid chromatography (HPLC) silica column material. The immobilization was performed by binding amino groups in HA/FA to the free aldehyde group in glutardialdehyde attached to the silica gel. The HPLC column materials were compared with a blank column material made by applying the same procedure but without immobilizing HA or FA. Also, a column was made by binding carbonyl groups in HA to amino groups attached to the silica gel. The humic substances were selected to secure appropriate variation of their structural features. The retention factors of 45 polycyclic aromatic compounds (PAC) to the four columns were determined by HPLC. The advantage of the technique is a large number of compounds can easily be studied. The binding procedure does not appear to cause a drastic selection between the HA molecules. The k' values obtained for the two Aldrich HA columns agree in general reasonably. The retention or sorption of the compounds increased with the size of the PAC and the number of lipophilic substituents, but decreased when polar substituents were present. The PAC retention was much stronger to the two HA columns than to the FA and blank column, both for hydrophobic polycyclic aromatic hydrocarbons (PAH) and the polar PAC. Other factors impacting the PAC binding may be specific interactions with HA and the ionic strength of the aqueous phase. The technique has been applied to do direct determinations of Koc.     

Bioremediation of residual fertilizer nitrate: II. Soil redox potential and soluble iron as indicators of soil health during treatment

The prospect of using wastewater containing high loads of soluble organic matter (OM) for removing residual agricultural chemicals (fertilizer, pesticide, or herbicide) in farm soil, although promising, could have adverse effects on soil agricultural quality as a result of development of redoximorphic features in the soil profile. In this study, the effect of organic carbon supplement for bioremediation of residual fertilizer nitrate on soil properties, redox potential (Eh), pH, and metal ion mobilization was studied using sandy soils packed in columns. The study was included in a general project, described elsewhere (Ugwuegbu et al., 2000), undertaken to evaluate use of controlled water table management (WTM) systems to supply organic carbon for creating a reduced environment conducive to denitrification of residual fertilizer nitrate leaching from the farm to subsurface water. The columns were subjected to subirrigation with water containing soluble organic carbon in the form of glucose. The work was carried out in two experimental setups and the long-term effect of a range of glucose concentrations on the Eh, pH, and soluble levels of Fe and Mn was investigated. From the results obtained, it could be concluded that excessive organic carbon supplement to soil can have adverse effects on soil quality and that Eh and soluble Fe are the two most practical parameters for monitoring soil health during treatment of farm chemicals.     

A Paradigm of International Environmental Law: The Case for Controlling the Transboundary Movements of Hazardous Wastes

The production of large quantities of wastes globally has created a commercial activity involving the transfrontier shipments of hazardous wastes, intended to be managed at economically attractive waste-handling facilities located elsewhere. In fact, huge quantities of hazardous wastes apparently travel the world in search of “acceptable” waste management facilities. For instance, within the industrialized countries alone, millions of tonnes of potentially hazardous waste cross national frontiers each year on their way for recycling or to treatment, storage, and disposal facilities (TSDFs) because there is no local disposal capacity for these wastes, or because legal disposal or reuse in a foreign country may be more environmentally sound, or managing the wastes in the foreign country may be less expensive than at home. The cross-boundary traffic in hazardous wastes has lately been under close public scrutiny, however, resulting in the accession of several international agreements and laws to regulate such activities. This paper discusses and analyzes the most significant control measures and major agreements in this new commercial activity involving hazardous wastes. In particular, the discussion recognizes the difficulties with trying to implement the relevant international agreements among countries of vastly different socioeconomic backgrounds. Nonetheless, it is also noted that global environmental agreements will generally be a necessary component of ensuring adequate environmental protection for the world community—and thus a need for the careful implementation of such agreements and regulations.     

Environmental indices in irrigation management

Irrigation management calls for objective criteria capable of representing the economy, reliability, and productivity of irrigation systems. These criteria must be compatible with long-term sustainability and conservation goals. The criteria representing the above goals are the economic effect of management on yield reduction, economic effect, and reliability referring to plant growth and operation of the network. In this study environmental indices are introduced to express the above criteria in quantitative terms. The inclusion of these indices at the farm and network level create a multicriteria framework for decision-making based on composite programming. An experimental study was conducted during the irrigation periods of 1989 and 1990 in Chania, Greece, concerning water delivered to 40 experimental plots, soil moisture content at the rootzone, and irrigation system operational failures. The data collected in real time were used for the calculation of the corresponding environmental indices. The variation in time and space is high and resulted in up to 62% of yield loss and low system performance (up to 7% of system temporal reliability). The study indicated that environmental indices could be incorporated to select alternatives and also to develop policies on water delivery. The final decision involves a trade-off analysis between cost of application and desired system performance. Measures of both primary objectives can be obtained using environmental indices that represent system operation aggregation at its basic levels (on farm and network).