Status of trace elements in paddy soil and sediment in Taihu Lake region

Thirteen paddy soil profiles and river sediments which are sources of irrigation water were collected around the Taihu Lake, and the trace elements were estimated. The content of La and Ce in paddy soil and sediment were 39.3 and 68.6 mg/kg soil and 36.9 and 65.1 mg/kg soil, being within the range of background values. The values for Pb, Cu, Ni, Cr, Co, Mn, Zn, Se in paddy soil were 23.3, 27.8, 25.5, 63.5, 10.2, 386, 68.7 and 0.25 mg/kg soil respectively, all below the national permission level. There was a decline of Zn in paddy soil. Some of the river sediments were seriously polluted. The river in Yangjin site was most contaminated with 5.47 g Cu/kg and 7.4 g Zn/kg. The high concentration of Pb and Ni also was observed in this sediment. River in Weitang, Huashi, Xinzhuang and Meiyan were contaminated with Pb, Cu and Ni to some extent. Zn, Cu and Pb were the main pollutants in present experiment sites. The fast development of village/township industries have caused severe environmental pollution in the Taihu Lake region, especially irrigation river sediments. Se content in plant and seed was 0.04 and 0.03 mg/kg respectively, showed Se-deficiency in paddy soil in the Taihu Lake region.     

Evidence of degradation of polybrominated biphenyls in soil samples from michigan

Abstract

Soil samples obtained from the former polybrominated biphenyls (PBB) manufacturing site in Michigan were analyzed by gas chromatography and gas chromatography with mass spectrometric detection. The results indicate significant degradation of the PBB residue in the soil sample. The soil sample with the highest concentration of PBB has the greatest degree of degradation. Principal degradation products include 2,3’,4,4’,5‐pentabromo‐biphenyl, 2,2’,4,4’,5‐pencabromobiphenyl and two unidentified tetrabromobiphenyls.

The degradation pattern observed supports a photochemical decomposition mechanism. These degraded residues may be more toxic than the original Firemaster residues. The implications of the results are discussed.     

Toxic effects of carbofuran and glyphosate on semen characteristics in rabbits

Abstract

The present study was undertaken to investigate the effect of chronic treatment with two sublethal doses of Carbofuran (carbamate insecticide) and Glyphosate (organophosphorus herbicide) on body weight and semen characteristics in mature male New Zealand white rabbits. Pesticide treatment resulted in a decline in body weight, libido, ejaculate volume, sperm concentration, semen initial fructose and semen osmolality. This was accompanied with increases in the abnormal and dead sperm and semen methylene blue reduction time. The hazardous effect of these pesticides on semen quality continued during the recovery period, and was dose‐dependent. These effects on sperm quality may be due to the direct cytotoxic effects of these pesticides on spermatogenesis and/or indirectly via hypothalami‐pituitary‐testis axis which control the reproductive efficiency.     

Assessing Landscape Condition Relative to Water Resources in the Western United States: A Strategic Approach

The Environmental Monitoring and Assessment Program (EMAP) is proposing an ambitious agenda to assess the status of streams and estuaries in a 12-State area of the western United States by the end of 2003. Additionally, EMAP is proposing to access landscape conditions as they relate to stream and estuary conditions across the west. The goal of this landscape project is to develop a landscape model that can be used to identify the relative risks of streams and estuaries to potential declines due to watershed-scale, landscape conditions across the west. To do so, requires an understanding of quantitative relationships between landscape composition and pattern metrics and parameters of stream and estuary conditions. This paper describes a strategic approach for evaluating the degree to which landscape composition and pattern influence stream and estuary condition, and the development and implementation of a spatially-distributed, landscape analysis approach.     

Higher pH and faster decomposition in biowaste composting by increased aeration

Composting of source separated municipal biowaste has at several plants in Scandinavia been hampered by low pH. In this study the hypothesis that increased aeration would improve the process was tested in full-scale experiments at two large composting plants. The O2 concentrations were high (>15%) even at the low aeration rates, so the prevailing low pH was not due to an anaerobic process environment. In spite of this, increased aeration rates at the start of the process resulted in higher microbial activity, increased pH and a more stable compost product. At one plant the decomposition rate varied in proportion to the aeration rate, to the extent that the temperatures and O2 concentrations were similar during the early processes even though aeration rates varied between 10 and 50 m3/(h, m3 compost). However, increased aeration caused severe drying of the compost, but at one plant the addition of water was adequate to prevent drying. In conclusion, by increasing the aeration rates and adding water to compensate for drying, it was possible to shorten the time needed to produce a stable compost product and thus to increase the efficiency of the composting plants.     

Improvements of nano-SiO2 on sludge/fly ash mortar

Sewage sludge ash has been widely applied to cementitious materials. In this study, in order to determine effects of nano-SiO(2) additives on properties of sludge/fly ash mortar, different amounts of nano-SiO(2) were added to sludge/fly ash mortar specimens to investigate their physical properties and micro-structures. A water-binding ratio of 0.7 was assigned to the mix. Substitution amounts of 0%, 10%, 20%, and 30% of sludge/fly ash (1:1 ratio) were proposed. Moreover, 0%, 1%, 2%, and 3% of nano-SiO(2) was added to the mix. Tests, including SEM and compressive strength, were carried out on mortar specimens cured at 3, 7, and 28 days. Results showed that sludge/fly ash can make the crystals of cement hydration product finer. Moreover, crystals increased after nano-SiO(2) was added. Hence, nano-SiO(2) can improve the effects of sludge/fly ash on the hydration of mortar. Further, due to the low pozzolanic reaction active index of sludge ash, early compressive strengths of sludge/fly ash mortar were decreased. Yet, nano-SiO(2) could help produce hydration crystals, which implies that the addition of nano-SiO(2) to mortar can improve the influence of sludge/fly ash on the development of the early strength of the mortar.     

Leachability and metal-binding capacity in ageing landfill material

In order to study the stability of landfilled heavy metals, landfill material from a combined household and industrial waste landfill was aerated for 14 months to simulate the natural ageing processes as air slowly begins to penetrate the landfill mass. During aeration, the pH of the landfill material decreased from around 8.6 to 8.1 and the carbon content also decreased. In order to investigate the possible fate of metals in ageing landfills, a four-stage sequential extraction technique was applied. The ability of the materials to bind metal ions by electrostatic attractions and to form stronger complexes was studied separately. The amount of exchangeable cations, the capacity to bind metal ions by electrostatic attraction and the capacity of the landfill material to complex copper ions were increased by the aeration process. However, results from the sequential analysis showed an increased solubility of sulphur and some metals (Cd, Co, Cu, Ni and Zn). Equilibrium speciation models (Medusa) indicated that the organic matter deposit had a significant capacity to bind metal ions provided that pH was sufficiently high. However, as carbonates are consumed over time, the risk for metal mobility increases. Therefore, the landfills can become an environmental risk, depending on variations in the solubility of metal ions due to changes in pH, redox status and the availability of organic material.     

Control of GHG emission at the microbial community level

All organic material eventually is decomposed by microorganisms, and considerable amounts of C and N end up as gaseous metabolites. The emissions of greenhouse relevant gases like carbon dioxide, methane and nitrous oxides largely depend on physico-chemical conditions like substrate quality or the redox potential of the habitat. Manipulating these conditions has a great potential for reducing greenhouse gas emissions. Such options are known from farm and waste management, as well as from wastewater treatment. In this paper examples are given how greenhouse gas production might be reduced by regulating microbial processes. Biogas production from manure, organic wastes, and landfills are given as examples how methanisation may be used to save fossil fuel. Methane oxidation, on the other hand, might alleviate the problem of methane already produced, or the conversion of aerobic wastewater treatment to anaerobic nitrogen elimination through the anaerobic ammonium oxidation process might reduce N2O release to the atmosphere. Changing the diet of ruminants, altering soil water potentials or a change of waste collection systems are other measures that affect microbial activities and that might contribute to a reduction of carbon dioxide equivalents being emitted to the atmosphere.     

Atrazine and alachlor transport in claypan soils as influenced by differential antecedent soil water content

Increased attention to ground water contamination has encouraged an interest in mechanisms of solute transport through soils. Few studies have investigated the effect of the initial soil water content on the transport and degradation of herbicides for claypan soils. We investigated the effect of claypan soils at initial field capacity vs. permanent wilting level on atrazine and alachlor transport. The soil studied was Mexico silt loam (fine, smectitic, mesic Aeric Vertic Epiaqualf) with a subsoil clay content, primarily montmorillonite, of >40%. Strontium bromide, atrazine, and alachlor were applied to plots; half were at field capacity (Wet treatment), and half were near the permanent wilting point (Dry treatment). Soil cores were removed at selected depths and times, and cores were analyzed for bromide and herbicide concentrations. Bromide, atrazine, and alachlor were detected at the 0.90-m depth in dry plots within 15 d after experiment initiation. Bromide was detected 0.15 m deeper (P < 0.05) in the Dry compared with the Wet treatment at 1, 7, and 60 d after application and >0.30 m deeper (P < 0.01) in the Dry treatment at 15 and 30 d after application; similar treatment results were found for atrazine and alachlor, although on fewer dates with significant differences. The mobility order of the applied chemicals was bromide > atrazine > alachlor. The atrazine apparent half-life was significantly longer in the Dry plots compared with the Wet plots. The retardation factor determined from the relative velocity of each herbicide to that of bromide was higher for alachlor than for atrazine. This study identifies the impact that shrinkage cracks have for different moisture conditions on preferential transport of herbicides in claypan soils.     

Sorption of the veterinary antimicrobials sulfadimethoxine and ormetoprim in soil

Currently, limited research on the fate of antimicrobials in the environment exists, once they are discharged in human and animal wastes. Sorption of two antimicrobials, sulfadimethoxine (SDM) and ormetoprim (OMP), was investigated in two soils and sand using a series of batch experiments. Because OMP and SDM are often administered in combination, their sorption was also investigated in combination as co-solutes. The rate of SDM and OMP sorption was rapid over the first few hours of the experiments, which then slowed considerably after 16 to 68 h. OMP sorption was enhanced at high concentrations when in combination with SDM, with linear sorption coefficients ranging from 1.3 to 58.3 L.kg(-1) in the single solute experiments and 4.96 to 89.7 L.kg(-1) in the co-solute experiments. Sorption of OMP as a single solute seems to provide a better fit with the Freundlich equation, which became more linear (n approached 1) when SDM was present. Overall, SDM sorbed less than OMP in the two soils and sand. SDM linear sorption coefficients ranged from 0.4 to 25.8 L.kg(-1) as a single solute and 2.5 to 22.1 L.kg(-1) as a co-solute. Sorption of SDM becomes more nonlinear (n < 1) when SDM is present in combination with OMP. Overall, sorption of both antimicrobials increased in the selected soils and sand as the organic matter, clay content, and cation exchange capacity increased. These experiments indicate relatively low sorption of SDM and OMP in natural soils, making them a potential threat to surface and ground water.