A model for the prediction of oil slick movement and spreading using cellular automata

A model for the prediction of oil slick movement and spreading, using Cellular Automata, is presented in this paper. The model is general and can predict the behaviour of oil slicks in regions with complicated boundaries. The effects of winds, surface currents, and oil evaporation have been taken into account. An algorithm for the simulation of oil slick movement and spreading, based on this model, has also been developed and has been used to simulate hypothetical oil slicks in hypothetical geographical regions. The results of the simulation are in qualitative agreement with real oil slick movement and spreading.     

A review for chromium removal by carbon nanotubes

Water pollution is still a serious problem for the entire world. Adsorption technology is a promising process which is based on the fabrication of novel, cheap, non-dangerous and highly sorptive materials for application in wastewater purification processes. Nanomaterials are functional groups which find use in many important fields such as medicine, food processing and agriculture. This review collects information from published works about the use of carbon nanotubes as efficient and promising adsorbents in chromium removal from (real or synthesised) wastewater. For this purpose, isotherm (Langmuir, Freundlich, etc.), kinetic (pseudo-first-, second-order, etc.), thermodynamic (free-energy Gibbs, enthalpy, entropy) and desorption–regeneration studies were discussed in detail. Moreover, significant factors such as pH, agitation time, temperature, adsorbent dosage and initial dye concentration are also reported extensively. The maximum monolayer adsorption capacities of Cr(III) and Cr(VI) ions were 0.39–238.09 and 1.26–370.3?mg/g, respectively. The absolute values of ΔG⁰ and ΔH⁰ ranged 0.237–48.62 and 0.16–58.43?kJ/mol, respectively.     

Exposure to inhalable dust and endotoxin among Danish livestock farmers: results from the SUS cohort study

Studies on personal dust and endotoxin concentrations among animal farmers have been either small or limited to a few sectors in their investigations. The present study aimed to provide comparable information on the levels and variability of exposure to personal dust and endotoxin in different types of animal farmers. 507 personal inhalable dust samples were collected from 327 farmers employed in 54 pig, 26 dairy, 3 poultry, and 3 mink farms in Denmark. Measurements in pig and dairy farmers were full-shift and performed during summer and winter, while poultry and mink farmers were monitored during 4 well-defined production stages. The collected samples were measured for dust gravimetrically and analyzed for endotoxin by the Limulus amebocyte lysate assay. Simple statistics and random-effect analysis were used to describe the levels and the variability in measured dust and endotoxin exposure concentrations. Measured inhalable dust levels had an overall geometric mean of 2.5 mg m(-3) (range 相似文献   

Soil pollution under the effect of treated municipal wastewater

Soil heavy metal pollution due to wastewater reuse was assessed by means of the concentration factor (CF) and/or pollution load index (PLI).In this respect, a greenhouse pot experiment was conducted, using a completely randomized block design, including five treatments of treated municipal wastewater (0%, 25%, 50%, 75%, and 100%), in four replications. Brassica oleracea var. Capitata was used as a test crop. The optimum CFs were expressed as a function of maximum dry matter of cabbage plant parts yield, and the values obtained per plant part were as follows: stems-Zn-CF 2.96, Co-CF 0.85, Ni-CF 0.92; whole plant-Cu-CF 3.90, Ni-CF 0.87, and Pb-CF 11.52; and leaves-Pb-CF 11.78. The PLI was calculated as the geometric mean of the CF of each metal, and was related to the maximum dry mater yield of cabbage stems and heads. The optimum values found were: stems PLI 1.99-2.55 and heads 2.25.     

Exposure to major volatile organic compounds and carbonyls in European indoor environments and associated health risk

This paper summarizes recent data on the occurrence of major organic compounds (benzene, toluene, xylenes, styrene, acetaldehyde, formaldehyde, naphthalene, limonene, α-pinene and ammonia, classified by the European Commission's INDEX strategy report as the priority pollutants to be regulated) and evaluates accordingly cancer and non-cancer risks posed by indoor exposure in dwellings and public buildings in European Union (EU) countries. The review process indicated that significant differences in indoor air quality exist within and among the countries where data were available, indicating corresponding differences in sources and emission strength of airborne chemicals, identified or not. Conservative exposure limits were not exceeded for non-carcinogenic effects, except for formaldehyde; for carcinogenic agents the estimated risks were up to three orders of magnitude higher than the one (10(-6)) proposed as acceptable by risk management bodies. However, the risk assessment evaluation process faces crucial difficulties, either due to the relative paucity of indoor air quality measurements in many EU countries, or by the lack of sampling consistency in the already existing studies, indicating the need for additional measurements of indoor air quality following a harmonized sampling and analytical protocol. Additionally, uncertainties embodied in the cancer potency factors and exposure limit values impose further difficulties in substance prioritization and risk management.     

Passive sampling of selected pesticides in aquatic environment using polar organic chemical integrative samplers

Purpose  

Polar chemical integrative samplers (POCIS) were examined for their sampling efficiency of 12 pesticides and one metabolite commonly detected in surface waters. Laboratory-based calibration experiments of POCISs were conducted. The determined passive sampling rates were applied for the monitoring of pesticides levels in Lake Amvrakia, Western Greece. Spot sampling was also performed for comparison purposes.