Biogeochemical cycle of arsenic and calculating the enrichment factor by using Li element

Adsorption behavior of Sudan I-IV on a coastal soil and their forecasted biogeochemical cycles

Sudan I-IV as synthetic azo dyes have been concerned worldwide and ever caused a panic on food safety because of illegal addition into foodstuffs. In the past decades, various methods are being developed to identify and determine Sudan dyes in foodstuffs. However, relevant studies about their biogeochemical behaviors and potential environmental effects are rarely reported, although it is of great importance and necessity accounting for their potential environmental contamination from various sources. In this work, the experimental studies on adsorption behavior of Sudan I-IV acting on soil (10, 25, 50, 75, and 100 mg/L) were carried out, and their transport in soil compartments and between soil-water, and air-soil interfaces were discussed. Results showed that the amount of Sudan I-IV adsorbed on soil increased accordingly with the increasing concentration of Sudan dyes in aqueous solution, and Sudan II and IV were more likely adsorbed on the tested soils than Sudan I and III based on their maximum adsorption amount. However, for Sudan I, III, and IV, in some high concentrations (under the treatment of 75 mg/L for Sudan III, 100 mg/L for Sudan I and IV), the adsorption was significantly increased, and then came back to the "normal" level (under the treatment of 100 mg/L for Sudan III). It is expected that relevant researches on their biogeochemical behaviors in soil compartments, and between soil-water and air-soil interfaces would be concerned and addressed.

Isolation and characterization of arsenic resistant bacteria from wastewater

The present study proposed the isolation of arsenic resistant bacteria from wastewater. Only three bacterial isolates (MNZ1, MNZ4 and MNZ6) were able to grow in high concentrations of arsenic. The minimum inhibitory concentrations of arsenic against MNZ1, MNZ4 and MNZ6 were 300 mg/L, 300 mg/L and 370 mg/L respectively. The isolated strains showed maximum growth at 37 °C and at 7.0 pH in control but in arsenite stress Luria Bertani broth the bacterial growth is lower than control. All strains were arsenite oxidizing. All strains were biochemically characterized and ribotyping (16S rRNA) was done for the purpose of identification which confirmed that MNZ1 was homologous to Enterobacter sp. while MNZ4 and MNZ6 showed their maximum homology with Klebsiella pneumoniae. The protein profiling of these strains showed in arsenic stressed and non stressed conditions, so no bands of induced proteins appeared in stressed conditions. The bacterial isolates can be exploited for bioremediation of arsenic containing wastes, since they seem to have the potential to oxidize the arsenite (more toxic) into arsenate (less toxic) form.

Sources of metal pollution in the urban atmosphere (A case study: Tuzla, Istabul)

In this study, İstanbul-Tuzla Region atmosphere was selected as the working area for atmospheric pollution. Although the study area seems too local, this region contains shipyards and shipyard-related side product industries. It is also surrounded by aluminum (ASSAN) and copper (SARKUYSAN) facilities and tannery organized industrial district. For determined the atmospheric inputs, the sample collection was carried out as monthly in 2010. Particulate matter was filtered from aerosols via a high volume air sampler. The collected 46 ambient air samples were analyzed for Cr, Fe, Cu, Zn, Cd, Pb and Al using Atomic Absorption Spectrometry (AAS), Flame unit. Additionally, the volume of the air was drawn and meteorological data recorded. Average individual heavy metal concentrations were found as Cd (0.06 ng/m(3)) < Cr (0.09 ng/m(3)) < Zn (0.21 ng/m(3)) < Pb (0.23 ng/m(3)) < Cu (0.48 ng/m(3)). The concentrations of crustal elements Fe and Al were changed between 5.48 ng/m(3), 74 ng/m(3) and 14 ng/m(3), 284 ng/m(3) respectively during the sampling period. Except Cr and Fe anthropogenic contribution was seen on the concentrations of Zn, Cu, Pb and Cd in an increasing order. While the crustal element Fe was not show an appreciable change in concentration, but the Al concentration was display an important change in concentration depending on the wind transportation.

Historical trends in the anthropogenic heavy metal levels in the tidal flat sediments of Lianyungang, China

The sedimentation of metals can preserve the historical record of contaminant input from local and regional sources and provide information on the historical changes in regional water and sediment quality. We report the 210Pb activities and the heavy metal (Cd, Cr, Cu, Mn, Pb and Zn) depth profiles from sediment cores retrieved in 2010. The mean sedimentation rates of 0.85-1.5 cm/yr are determined by 210Pb dating. The sediments in the tidal flat have recorded heavy metal deposition and thus allow the establishment of a connection between the temporal evolution of the heavy metal pollution and the historical changes in the economic development of Lianyungang. The enrichment factors (EF) are calculated to estimate the level of contamination stored in these sediments. The results show that in the studied sites, Cr and Cu display low EF values and are mainly from lithogenic origin. For the other studied trace metals, a great variability in the sedimentary record is observed. Significant anthropogenic enrichment over the last 50 years is revealed at the tidal flat that receives fluvial inputs. Zinc is the element with the highest EF values, followed by the order of Pb > Cd > Mn > Cu and Cr. The temporal variations of the heavy metals peak during the late 1980s to the early 2000s and show a decreasing trend afterward. The pollution intensity of the tidal flat is determined by using EF and the geo-accumulation index (I(geo)), which show that, based on the l(geo) scale, the tidal flat of Haizhou Bay is unpolluted to moderately polluted.