The European whitefish, Coregonus lavaretus (L.), under conditions of technogenic pollution in the Kostomuksha tailing pond

The population structure and biological parameters of the European whitefish, Coregonus lavaretus (L.), have been analyzed in a technogenically polluted water body. The biochemical state of the whitefish and the fauna and morphology of helminths parasitizing them have been assessed. It is shown that the species composition of the fish, plankton, benthos, and parasite faunas of this water body are depleted and the morphological parameters of common fish parasites are altered. It is noted that, in addition to adaptive rearrangements in biochemical metabolism, the whitefish from the transformed water body are characterized by a reduction in the level of protein synthesis in muscles and the rate of aerobic energy metabolism in the liver and muscles.     

Anaerobic microbial dechlorination: an approach to on-site treatment of toxaphene-contaminated soil

Enhanced microbial degradation of toxaphene by natural microorganisms occurred in soil and sediment amended with organic matter kept under anaerobic (flooded) conditions. Laboratory experiments yielded a dissipation half-life of approximately 3 and 1 week for soil and sediment, respectively, containing 10 ppm of technical toxaphene and a 1% alfalfa meal amendment. Dissipation was accompanied by an increase in early eluting gas chromatographic peaks and a decrease in later eluting peaks, indicating that dechlorination had occurred. Enhanced anaerobic dissipation also took place in soil containing 500 ppm of toxaphene, although at a lesser rate than at 10 ppm, and when cotton gin waste was used as amendment in place of alfalfa meal. Sediment in a toxaphene-contaminated pesticide waste disposal ditch was amended with 10% steer manure and flooded to ascertain field utility of the technique for on-site decontamination. Toxaphene residues were reduced from 63 to 23 ppm in 120 days, and some degradation activity still occurred up to 8 months after this single treatment.     

Use of Approximate Inference in an Index of Completeness of Biological Inventories

Abstract:  To assess the completeness of a floristic or faunal inventory, one may use the ratio of the observed number of species to the "true number" of species ( C ). If the inventory is complete , C = 1. The estimate of the true number can be obtained from accumulation curves, nonparametric methods, or other techniques. We devised a simple method for computing confidence intervals (CI) for C and for evaluating the null hypothesis that the inventory is complete. The method is based on the assumptions that an estimate of the variance of the true number of species is known and that the distribution of the estimator of the true number of species is approximately normal. We applied our method to bird inventories in the Balsas Basin of Mexico. The completeness index for subtransects were lower (84.0, 85.4, and 89.9%) than for the whole transect (91.6%) (all significantly different from 100%). Thus, these particular inventories were incomplete at 2 spatial resolutions. Our method of estimating CI for C can be used to estimate species richness obtained from databases of different sites or to test the null hypothesis that an inventory derived from a database is complete.     

Determination of sorbent point zero charge: usefulness in sorption studies

Potentiometric mass titration (PMT) technique has been adapted to determine the pH _pzc of four vegetable wastes: grape stalks, cork, yohimbe bark and olive stones wastes used for Cu(II) removal. The pH at the point zero charge (pH _pzc), determined by PMT, are compared with that obtained by two classical techniques: mass titration (MT) and immersion technique (IT). PMT has been found to be an easy and appropriate technique to determine pH _pzc of the studied materials. From the results, the knowledge of sorbents pH _pzc provides information about the possible attraction and repulsion between sorbent and sorbate but in any case enables to ensure that electrostatic force is one of the mechanisms that takes place in metal sorption.     

Enhancement of the anaerobic hydrolysis and fermentation of municipal solid waste in leachbed reactors by varying flow direction during water addition and leachate recycle

Poor performance of leachbed reactors (LBRs) is attributed to channelling, compaction from waste loading, unidirectional water addition and leachate flow causing reduced hydraulic conductivity and leachate flow blockage. Performance enhancement was evaluated in three LBRs M, D and U at 22 ± 3 °C using three water addition and leachate recycle strategies; water addition was downflow in D throughout, intermittently upflow and downflow in M and U with 77% volume downflow in M, 54% volume downflow in U while the rest were upflow. Leachate recycle was downflow in D, alternately downflow and upflow in M and upflow in U. The strategy adopted in U led to more water addition (30.3%), leachate production (33%) and chemical oxygen demand (COD) solubilisation (33%; 1609 g against 1210 g) compared to D (control). The total and volatile solids (TS and VS) reductions were similar but the highest COD yield (g-COD/g-TS and g-COD/g-VS removed) was in U (1.6 and 1.9); the values were 1.33 and 1.57 for M, and 1.18 and 1.41 for D respectively. The strategy adopted in U showed superior performance with more COD and leachate production compared to reactors M and D.