Distribution of Trace Metals in the Surface Sediments of Two Pristine Subalpine Lakes in Taiwan

Sediment cores were collected from two remote subalpine lakes: the rather shallow (1.5 m) Little Ghost Lake at 2040 m elevation and the deeper, Great Ghost Lake (40 m) at 2150 m elevation. Different early diagenesis of metals were observed. the seasonally anoxic hypolimnion drives the annual iron redox cycle and causes the remobilization of metals in the mobile fractions of sediments in the Great Ghost Lake. These result in the redistribution of metals in the mobile fractions of sediment and poor correlation between metal concentrations. in the Little Ghost Lake, the shallow water column is always oxic with less change of metals in the mobile fractions of sediments. As a result, most metals have strong positive correlations with each other.

The distributions of metal/Al ratios, total metal contents and acid-leached metal concentrations in the near-surface sediments of these two lakes suggest that the anthropogenic inputs from the atmospheric fallouts in recent decades are one of the major factors affecting the distributions of metals such as cadmium, lead and, to a lessor extent, zinc. the Pb-206/Pb-207 ratios confirm the anthropogenic lead input in these surface sediments.     

GROWTH INHIBITION OF HYDRILLA VERTICILLATA BY SELECTED LAKE SEDIMENT EXTRACTS1

ABSTRACT: Sediments were investigated from two Florida lakes that have not been infested with the submersed, perennial, noxious plant Hydrilla verticillata. Aqueous extracts of the peat-like sediments from these lakes were shown to inhibit the growth of Hydrilla verticillata in laboratory systems. The extracts have substantial concentrations of organic carbon and iron. The apparent molecular weight of the inhibitory fraction is between 2,000 and 10,000, based upon ultrafiltration studies. Hydrilla growth was about 35 percent relative to control for a partially purified fraction at a level of 0.4 ppm organic carbon. Growth was measured as change in biomass (wet and dry) over a one-week period. The inhibitory material was highly fluorescent, dark brown, and inhibitory activity was lost after passage over an anion-exchange column (Cellex-D).     

BENEFITS FROM WATER CONSERVATION DEPEND ON COMPREHENSIVE PLANNING1

: Substantial reductions in municipal water use are feasible without reducing the quality of life. If conservation measures are preplanned, properly engineered, and coordinated, reductions in utility bills for water, waste water, and energy are estimated at $30+per person per year. Installation of devices to reduce water use, engineering plans to prevent malfunctioning of collecting sewers, and engineered process modifications of treatment facilities must be coordinated to achieve full benefits of water conservation. Pollutant discharges to the aquatic environment are reduced in direct proportion to the reduction in water use.     

PHOSPHORUS ACCUMULATION - DISCHARGE CYCLES IN MARSHES1

ABSTRACT: Artificial and natural marshes were studied to determine changes in quality of polluted water passing through them. Phosphorus removal ranged from zero to 64%. Removals in the 35% range were common, however. Much of the phosphorus went into sediments and unharvestable plant parts. Harvesting vegetation removed 6% of the phosphorus put into the system. Accumulation of phosphorus during the growing season was about 20 g*m^?2, much of which was flushed out after the onset of freezing weather. The amount of phosphorus flushed out can be prevented from entering a lake or stream by handling the marsh discharge in one of three ways; irrigate on land, lagoon to recycle later, treat conventionally if facilities are available.     

Estimation of Similarity in the Qualitative Composition of Humic Substance in Marine Sediments By Means of an Uv-Spectroscopic Library

In this paper a method for the study of the qualitative similarity of extractable humic substance (EHS) in marine sediments based on the realisation of UV spectral library of EHS is described. the spectral library was built including the digitised spectra of humic substance extracted from several marine sediments (46 samples) and two samples of standard materials (lignin sulphonate and humic substance) in a Statistica data file. the data matrix was elaborated by means of different multivariate statistic techniques such as Cluster Analysis (CA), Principal Components Analysis (PCA) and the univariate technique Spectral Correlation Analysis (SCA). This approach allows us to show the contribution of different organic compounds (aromatic, lipid and acid) to the composition of EHS and moreover it evidences also the structural characteristics of EHS in terms of similarities in the qualitative composition of samples such as presence of terrestrial and/or vegetal contributions. the UV library is an objective tool to study the qualitative composition of EHS and it represents a complementary approach to the most common methods based on the application of spectroscopic (IR, ¹³CNMR), potentiometric and chromatographic techniques.     

Distribution of radionuclides among the main components of Lake Chervyanoe in the Eastern Ural Radioactive Trace

Radioecological conditions have been estimated in Lake Chervyanoe located on the central axis of the Eastern Ural Radioactive Trace (EURT) about 100–110 km northeast of the Mayak Production Association. Data on the ⁹⁰Sr and ¹³⁷Cs contents in the main components of the lake, the distribution of these radionuclides over the profile of bottom sediments, and their amounts in the lake are presented. The experimental data have been used to construct mathematical models for estimating changes in the radionuclide concentrations and amounts in the water and bottom sediments of the lake over a long period after the nuclear accident, as well as the tritium content of the lake water in different periods of time.     

Biological treatment of fish processing wastewater: A case study from Sfax City (Southeastern Tunisia)

The present work presents a study of the biological treatment of fish processing wastewater at salt concentration of 55 g/L. Wastewater was treated by both continuous stirred-tank reactor (CSTR) and membrane bioreactor (MBR) during 50 and 100 days, respectively. These biological processes involved salt-tolerant bacteria from natural hypersaline environments at different organic loading rates (OLRs). The phylogenetic analysis of the corresponding excised DGGE bands has demonstrated that the taxonomic affiliation of the most dominant species includes Halomonadaceae and Flavobacteriaceae families of the Proteobacteria (Gamma-proteobacteria class) and the Bacteroidetes phyla, respectively. The results of MBR were better than those of CSTR in the removal of total organic carbon with efficiencies from 97.9% to 98.6%. Nevertheless, salinity with increasing OLR aggravates fouling that requires more cleaning for a membrane in MBR while leads to deterioration of sludge settleability and effluent quality in CSTR.     

Interactions Among the Copper Species and Forms in Sea Water/Sediments and Copper Bioaccumulation in Oysters

Abstract

Earlier papers indicated that the first incident of green discoloration in oysters (Crassostrea gigas) and the mass mortality observed in 1986 along the Taiwan Erhjin Chi coastal area were caused by the higher contents of total copper and copper species (mainly bioavailable and free ion) in sea water. the copper in sea water would be sorbed by suspended matter and transferred to sediments, and the copper in the sediments would also be desorbed to sea water. Processes of copper adsorption and desorption are the major factors influencing the contents of total copper and copper species in sea water and sediments. in this study, the Erhjin Chi sediments were mixed with sea water by a shaker technique. When the mixture was shaken for one hour, analogous to tidal mixing in estuaries, only copper desorption from sediments was observed. If the shaking time is increased for more than 3 hours, the copper released from the sediments was resorbed to the remaining solid phases. the higher the contents of mud (91.71%) and total copper (701 mg kg^?1) in sediments, the higher the copper desorption rate (1.86 ppm hr^?1) and copper adsorption rate (0.50 ppm hr^?1) were observed. in sediments containing lower mud (0.80%) and lower copper (43.5 mg kg^?1), the copper desorption and adsorption rates were 0.83 ppm hr^?1 and 0.22 ppm hr^?1, respectively. the interactions among the total copper and copper species in sea water and sediments, chemical and ecological parameters, and copper bioaccumulation in oysters in the Erhjin Chi estuarine and coastal area are also discussed.     

辽宁太子河沉积物重金属污染及潜在生态危害评价

为全面了解辽宁太子河底泥沉积物中重金属的污染特征,测试了太子河表层沉积物中重金属元素铜、铅、镉和锌的含量,并采用地积累指数法和潜在生态危害指数法评价了沉积物中重金属污染及其潜在生态危害程度。结果表明,辽宁太子河底泥沉积物中各种重金属元素的污染程度由强至弱依次为:Cd>Zn≥Cu>Pb;金属污染构成的潜在生态危害由强至弱依次为:Cd>Cu≈Zn>Pb,其中Cd的影响占绝对主导地位。     

水源水库污染底泥不同修复方法脱氮效果对比实验研究

总氮超标是大部分水源水库具有的共性水质问题.在外源污染得到有效控制,上游来水氮负荷较低的情况下,底泥內源氮释放对上覆水体水质影响巨大.因此,在泥水界面处对污染底泥进行合理修复以有效抑制底泥氮释放是解决总氮超标问题、控制水源水质的关键.本研究通过模拟实验对比研究了3种不同修复方法,即覆盖填料、投加功能微生物和投加铁粉在界面处的脱氮效果.结果表明,填料覆盖技术具有更明显的脱氮效果,对氨氮的平均抑制率为83%,最高时可达92%,对总氮的平均抑制率达73%,且效果稳定.