In vitro study of oxytetracycline adsorption on activated charcoal

In vitro adsorption experiments simulating pH in gastric environment and using Langmuir isotherm, showed that 408 mg of oxytetracycline was adsorbed per gram of activated charcoal. Langmuir isotherm fitted adsorption data better than a Freundlich isotherm. Freundlich isotherm showed a specific adsorption capacity of 518 mg/g for activated charcoal. Both isotherm parameters indicated a strong oxytetracycline adsorption on activated charcoal in terms of quantity and binding strength. The results demonstrate that the concomitant use of oxytetracyline and activated charcoal should be avoided.     

Removal of basic dye from waste-water using silica as adsorbent

The kinetics of removal of Basic Blue 3 from a textile effluent was studied using silica as an adsorbent. The adsorption was found to follow a first-order process. The influences on the rate of adsorption of various factors, such as temperature, concentration of dye solution, pH of the system and the amount of adsorbent have been investigated. On the basis of the isotherm studies, the various thermodynamical parameters have been calculated. The effect of electrolytes and surfactants has also been seen on the removal of the dye from the waste-water.     

Instrumental neutron activation analysis of ambient air dust particulates from metropolitan cities in India

Ambient air dust samples were collected from industrial, commercial and residential areas of four metropolitan cities (Delhi, Calcutta, Madras and Cochin) in India, and were analysed for 27 elements (As, Ba, Br, Ce, Co, Cr, Cs, Cu, Eu, Hf, Hg, Fe, Ga, La, Lu, Na, P, Sb, Sc, Se, Sr, Ta, Tb, Th, Rb, Yb and Zn) by Instrumental Neutron Activation Analysis (INAA). Samples were irradiated with thermal neutrons in a nuclear reactor for 1 day and counted by high resolution gamma spectrometry at different intervals. Several environmental standards such as Coal (SRM 1932b); Urban Particulate Matter (SRM 1648) from NIST, USA; Vehicle Exhaust from NIES, Japan; and Soil-5 from IAEA, Vienna were also analysed for quality assurance. The results reveal that the concentrations of several pollutant elements in dust samples from the four cities are highly variable. Wide differences were observed for elemental concentrations of As, Ba, Br, Cu, Cr, Hg, Fe, Sb, Se and Zn and these variations are explained in terms of their possible sources of origin.     

Enzymatic production of biosilica glass using enzymes from sponges: basic aspects and application in nanobiotechnology (material sciences and medicine)

Biomineralization, biosilicification in particular (i.e. the formation of biogenic silica, SiO₂), has become an exciting source of inspiration for the development of novel bionic approaches following “nature as model”. Siliceous sponges are unique among silica forming organisms in their ability to catalyze silica formation using a specific enzyme termed silicatein. In this study, we review the present state of knowledge on silicatein-mediated “biosilica” formation in marine sponges, the involvement of further molecules in silica metabolism and their potential application in nanobiotechnology and medicine. Werner E. G. Müller dedicated this study to Prof. Vera Gamulin (Rudjer Boskovic Institute, Zagreb, Croatia) in honour of her unique contributions in molecular evolution.     

Agricultural Land Use and Best Management Practices to Control Nonpoint Water Pollution

In recent years, improvements in point-source depuration technologies have highlighted the problems regarding agricultural nonpoint (diffuse) sources, and this issue has become highly relevant from the environmental point of view. The considerable extension of the areas responsible for this kind of pollution, together with the scarcity of funds available to local managers, make minimizing the impacts of nonpoint sources on a whole basin a virtually impossible task. This article presents the results of a study intended to pinpoint those agricultural areas, within a basin, that contribute most to water pollution, so that operations aimed at preventing and/or reducing this kind of pollution can be focused on them. With this aim, an innovative approach is presented that integrates a field-scale management model, a simple regression model, and a geographic information system (GIS). The Lake Vico basin, where recent studies highlighted a considerable increase in the trophic state, mainly caused by phosphorus (P) compounds deriving principally from the intensive cultivation of hazelnut trees in the lake basin, was chosen as the study site. Using the management model Groundwater Loading Effects of Agricultural Management Systems (GLEAMS), the consequences, in terms of sediment yield and phosphorus export, of hazelnut tree cultivation were estimated on different areas of the basin with and without the application of a best management practice (BMP) that consists of growing meadow under the trees. The GLEAMS results were successively extended to basin scale thanks to the application of a purposely designed regression model and of a GIS. The main conclusions can be summarized as follows: The effectiveness of the above-mentioned BMP is always greater for erosion reduction than for particulate P reduction, whatever the slope value considered; moreover, the effectiveness with reference to both particulate P and sediment yield production decreases as the slope increases. The proposed approach, being completely distributed, represents a considerable step ahead compared to the semidistributed or lumped approaches, which are traditionally employed in research into tools to support the decision-making process for land-use planning aimed at water pollution control.     

Pyrethroid use-malaria control and individual applications by households for other pests and home garden use

Presence of pyrethroid insecticides in human breast milk and in thatch wall material of dwellings from Southern Africa subtropical area (Manhiça, Mozambique) was investigated to assess potential pyrethroid route of human exposure. Human breast milk samples were collected during 2002 when pyrethroids were widely used as insecticides for mosquito bed nets in Mozambique for malaria control. The median concentration value of total pyrethroids ranged between 87 and 1200 ng/g lw, with λ-cyhalothrin being the most predominant pyrethroid in human breast milk contributing for 35% of the total amount. Moreover, and for the first time, an isomer-specific enrichment was found in human breast milk, showing a selective isomeric accumulation or metabolism in the human body. Based on the calculated pyrethroid concentrations in human breast milk, the daily ingestion rate of pyrethroid was estimated. The nursing infant dietary intake ranged from 0.67 to 9.0 μg (kg of body weight)^− 1 day^− 1. In addition, thatch materials collected after the reintegration of dichlorodiphenyltrichloroethene (DDT) as insecticide residual spraying (IRS) in Mozambique, showed the presence of pyrethroids with concentration values ranging between 6.9 and 700 ng/g dw. In thatch material as well as in human breast milk, pyrethroid contamination was mainly attributed to the agriculture usage of this insecticide knowing that agriculture represent the 80% of the economy in Mozambique. However, a possible usage of this insecticide as IRS in Mozambique cannot be excluded despite their low efficiency for malaria control. The continued use of these compounds (both for agriculture and malaria prevention) and the ingestion rates calculated from the breast milk concentrations indicate that these insecticides cannot be overlooked for the assessment of the lactation risks of breastfeeding infants from the Manhiça region.     

Trace analysis of persistent toxic substances in the main stream of Jiangsu section of the Yangtze River,China

Background, aim, and scope  

The Jiangsu section of the Yangtze River is the downstream of the whole river, serving as an important drinking water source. Persistent toxic substances (PTS), from the industries such as automobile, textile, chemical, and electronic production, are not listed in the National Standard yet and not monitored and controlled. However, pollution of PTS can threaten the environment and human health. In order to understand the pollution status of the PTS contamination and recommend future rationalization of countermeasure, the PTS including organochlorine pesticides (OCPs), polyaromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), and phthalates (PAEs) were investigated.     

An analytic network process model for municipal solid waste disposal options

The aim of this paper is to present an evaluation method that can aid decision makers in a local civic body to prioritize and select appropriate municipal solid waste disposal methods. We introduce a hierarchical network (hiernet) decision structure and apply the analytic network process (ANP) super-matrix approach to measure the relative desirability of disposal alternatives using value judgments as the input of the various stakeholders. ANP is a flexible analytical program that enables decision makers to find the best possible solution to complex problems by breaking down a problem into a systematic network of inter-relationships among the various levels and attributes. This method therefore may not only aid in selecting the best alternative but also helps decision makers to understand why an alternative is preferred over the other options.     

Efficient degradation of organic pollutants with ferrous hydroxide colloids as heterogeneous Fenton-like activator of hydrogen peroxide

The capacity of a full-scale reclamation pond-constructed wetland (CW) system to eliminate 27 emerging contaminants (i.e. pharmaceuticals, sunscreen compounds, fragrances, antiseptics, fire retardants, pesticides, and plasticizers) and the seasonal occurrence of these contaminants is studied. The compounds with the highest concentrations in the secondary effluent are diclofenac, caffeine, ketoprofen, and carbamazepine. The results show that the constructed wetland (61%) removes emerging contaminants significantly more efficiently than the pond (51%), presumably due to the presence of plants (Phragmites and Thypa) as well as the higher hydraulic residence time (HRT) in the CW. A greater seasonal trend to the efficient removal of these compounds is observed in the pond than in the CW. The overall mass removal efficiency of each individual compound ranged from 27% to 93% (71% on average), which is comparable to reported data in advanced treatments (photo-fenton and membrane filtration). The seasonal average content of emerging contaminants in the river water (2488 ng L⁻¹) next to the water reclamation plant is found to be higher than the content in the final reclaimed water (1490 ng L⁻¹), suggesting that the chemical quality of the reclaimed water is better than available surface waters.     

Simulating Dissolved Organic Carbon Dynamics at the Swedish Integrated Monitoring Sites with the Integrated Catchments Model for Carbon,INCA-C

Surface water concentrations of dissolved organic carbon ([DOC]) are changing throughout the northern hemisphere due to changes in climate, land use and acid deposition. However, the relative importance of these drivers is unclear. Here, we use the Integrated Catchments model for Carbon (INCA-C) to simulate long-term (1996–2008) streamwater [DOC] at the four Swedish integrated monitoring (IM) sites. These are unmanaged headwater catchments with old-growth forests and no major changes in land use. Daily, seasonal and long-term variations in streamwater [DOC] driven by runoff, seasonal temperature and atmospheric sulfate (SO₄ ²⁻) deposition were observed at all sites. Using INCA-C, it was possible to reproduce observed patterns of variability in streamwater [DOC] at the four IM sites. Runoff was found to be the main short-term control on [DOC]. Seasonal patterns in [DOC] were controlled primarily by soil temperature. Measured SO₄ ²⁻ deposition explained some of the long-term [DOC] variability at all sites.