Remedial Process Optimization and Ozone Sparging for Petroleum Hydrocarbon‐Impacted Groundwater

A former natural gas processing station is impacted with total petroleum hydrocarbons (TPH) and benzene. Remedial process optimization (RPO) was conducted to evaluate the effectiveness of the historical air sparging/soil vapor extraction (AS/SVE) system and the current groundwater extraction and treatment system. The RPO indicated that both remedial activities offered no further benefit in meeting remediation goals. Instead, an in situ chemical oxidation (ISCO) system was recommended. Ozone was selected, and the results of a bench test indicated that the ozone demand was 8 to 12 mg ozone/mg TPH and that secondary by‐products would include hexavalent chromium and bromate. A capture zone analysis was conducted through groundwater flow modeling (MODFLOW) to ensure containment of the injected oxidant using the existing groundwater extraction system. Results of a pilot study indicated that the optimum frequency of ozone sparging is 60 minutes in order to reach a maximum radius of influence of 20 feet. TPH concentrations within the treatment zone decreased by 97 percent over two months of ozone sparging. Concentrations of hexavalent chromium and bromate increased from nondetect to 44 and 110 mg/L, respectively, during the ozone sparging but attenuated to nondetectable concentrations within three months of system shut down. ©2016 Wiley Periodicals, Inc.     

Study of non-revenue water status and enforcement measures to reduce water loss: case study in villages of Kermanshah Province of Iran

In this study, the volume and the cash value of water loss, and reduction of water loss as a result of enforcement action during 2011–2013 in the drinking water network of villages in Kermanshah Province, Iran, have been investigated. Date collected by referring to the different parts of rural water and waste water company of Kermanshah Province and checklist were completed. The study showed the volume of produced water and sold water has increased and the water loss percentage has decreased. High cost of water production compared to revenue of sold water and water loss resulted in significant detriments in terms of the water production costs. Water loss level decreased from 33% to 30% as result of measures taken to reduce water loss but, it is still 15% higher than the world average level. Also the reduction in number of water resources and increase in the number and volume of reservoirs indicates a lack of water and a growing need. As result of high water loss, waste of costs in the contrast of water production cost and also because physical water loss accounts for most of the water loss of villages, necessary measures can be effective in reducing loss and have economic justification.     

Molecular diversity of arbuscular mycorrhizal fungi in relation to soil chemical properties and heavy metal contamination

Abundance and diversity of arbuscular mycorrhizal fungi (AMF) associated with dominant plant species were studied along a transect from highly lead (Pb) and zinc (Zn) polluted to non-polluted soil at the Anguran open pit mine in Iran. Using an established primer set for AMF in the internal transcribed spacer (ITS) region of rDNA, nine different AMF sequence types were distinguished after phylogenetic analyses, showing remarkable differences in their distribution patterns along the transect. With decreasing Pb and Zn concentration, the number of AMF sequence types increased, however one sequence type was only found in the highly contaminated area. Multivariate statistical analysis revealed that further factors than HM soil concentration affect the AMF community at contaminated sites. Specifically, the soils’ calcium carbonate equivalent and available P proved to be of importance, which illustrates that field studies on AMF distribution should also consider important environmental factors and their possible interactions.     

Contamination by organochlorine compounds in the edible tissue of four sturgeon species from the Caspian Sea (Iran)

This study focused on accumulation of organochlorine compounds (OCs), including dichloro-diphenyl-trichloroethanes (DDTs), hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and polychlorinated biphenyls (PCBs) accumulation in the muscle of four sturgeon (Persian sturgeon, Acipenser persicus; Stellate sturgeon, Acipenser stellatus; Ship sturgeon, Acipenser nudiventris and Beluga sturgeon, Huso huso) from the southern Caspian Sea. The DDT group was prominent in all of the sturgeon muscle tested constituting almost half or more of the total organochlorine content. Contaminant concentration generally followed this order: DDTs>PCBs>HCHs>HCB. The OCs concentrations in Beluga sturgeon (H. huso) were the highest and over four times higher than in the next highest species (A. nudiventris). From an ecotoxicological point of view, the concentrations of OCs in experimental fishes do not reflect a comparatively clean and pollution-free environment; however, results from this study shown that the inflow of organic pollutants into the Caspian Sea has been reduced when compared with prior studies. Levels of measured OCs in sturgeon were relatively low, but the level of some OCs in some of the specimens tested exceeded the guidelines for food; therefore, the maximum allowable daily consumption rate for sturgeon from this watershed may be limited by DDTs and PCBs content for high risk populations.     

Bioaerosols in the waterpipe cafés: genera,levels, and factors influencing their concentrations

Environmental Science and Pollution Research - This study was conducted in order to assess the exposure to bacterial and fungal bioaerosols in the air of waterpipe cafés (AWPCs), in the hose...     

Understanding communicational behavior among rangelands’ stakeholders: application of social network analysis

Understanding communicational behavior of rangelands’ stakeholders is fundamental for effective development of rangeland management plans. This study aimed to understand differences between stakeholders’ relations among various actors involved in rangeland management using social network analysis (SNA). A survey was conducted on 334 stakeholders (89 extension agents, 110 researchers and 135 executive agents) in the Tehran province, Iran. Results showed that all the three groups of stakeholders are interested in making contact mainly within their own group. Furthermore, while the executive agents have shared the strongest technical and friendship relations with the two other groups, the extension agents established the strongest administrative interactions. The researchers, however, made a poor link especially with the extension agents. The study concluded that SNA could be an efficient tool to assess communicational behavior in rangeland management.     

Response of coral assemblages to thermal stress: are bleaching intensity and spatial patterns consistent between events?

Mass bleaching events resulting in coral mortality are among the greatest threats to coral reefs, and are projected to increase in frequency and intensity with global warming. Achieving a better understanding of the consistency of the response of coral assemblages to thermal stress, both spatially and temporally, is essential to determine which reefs are more able to tolerate climate change. We compared variations in spatial and taxonomic patterns between two bleaching events at the scale of an island (Moorea Island, French Polynesia). Despite similar thermal stress and light conditions, bleaching intensity was significantly lower in 2007 (approximately 37 % of colonies showed signs of bleaching) than in 2002, when 55 % of the colonies bleached. Variations in the spatial patterns of bleaching intensity were consistent between the two events. Among nine sampling stations at three locations and three depths, the stations at which the bleaching response was lowest in 2002 were those that showed the lowest levels of bleaching in 2007. The taxonomic patterns of susceptibility to bleaching were also consistent between the two events. These findings have important implications for conservation because they indicate that corals are capable of acclimatization and/or adaptation and that, even at small spatial scales, some areas are consistently more susceptible to bleaching than others.     

Detection and quantification of chlordecone in contaminated soils from the French West Indies by GC-MS using the 13C10-chlordecone stable isotope as a tracer

Chlordecone is an organochlorine insecticide that has been widely used to control banana weevil in the French West Indies. As a result of this intense use, up to 20,000 ha are contaminated by this insecticide in the French West Indies, and this causes environmental damage and health problems. A scenario of exposure was drawn by French authorities, based on land usage records. Many efforts have been made to monitor the occurrence of chlordecone and its main metabolites using different analytical methods, including GC, GC/MS, LC/MS, and NIRS. Although these different methods allow for the detection and quantification of chlordecone from soils, none of them estimate the bottleneck caused by extraction of this organochlorine from soils with high adsorption ability. In this study, we used ¹³C₁₀-chlordecone as a tracer to estimate chlordecone extraction yield and to quantify chlordecone in soil extracts based on the ¹³C/¹²C isotope dilution. We report the optimization of ¹³C₁₀-chlordecone extraction from an Andosol. The method was found to be linear from 0.118 to 43 mg kg^?1 in the Andosol, with an instrumental detection limit estimated at 8.84 μg kg^?1. This method showed that chlordecone ranged from 35.4 down to 0.18 mg kg^?1 in Andosol, Nitisol, Ferralsol, and Fluvisol soil types. Traces of the metabolite β-monohydrochlordecone were detected in the Andosol, Nitisol, and Ferralsol soil samples. This last result indicates that this method could be useful to monitor the fate of chlordecone in soils of the French West Indies.     

Cloud point extraction–atomic absorption spectrometry for pre-concentration and determination of cadmium in cigarette samples

A new complexing agent, 2-((2-((1H-benzo[d]imidazole-2yl)methoxy)phenoxy)methyl)-1H-benzo[d]imidazole (BIMPI), was used in cloud point extraction and applied for selective pre-concentration of trace amounts of cadmium in cigarette samples. Cadmium was complexed with BIMPI in a buffer solution (pH?=?10) using Triton X-114 as surfactant and quantitatively extracted into a small volume of the surfactant-rich phase after centrifugation. Under optimized conditions (pH?=?10.0, 0.8?×?10^?4?mol?L^?1 BIMPI and 0.08 % (w/v) Triton X-114), calibration graph was linear in the range of 34.0–1,670.0 μg?L^?1. The proposed method was applied to the determination of Cd in various cigarette (tobacco) samples which gave satisfactory results.     

Effect of the water–oil ratio on brine/surfactant/alcohol/oil systems optimized for soil remediation

The optimum middle-phase microemulsion used for remediation of oily contaminated soils is often obtained by mixing a certain amount of a surfactant/alcohol mixture with oil and adjusting the salinity concentrations at a constant water–oil ratio. Upon introduction to the subsurface, however, the system may not be in the optimum state throughout the remediation process owing to the change in the water–oil ratio. This research has attempted to investigate the effect of the water–oil ratio on the phase behavior of systems containing brine, anionic surfactant, alcohols, and different oils. By systematically changing the water–oil ratio, while keeping the others variables constant, the systems exhibited different phase behavior. The results revealed that the effect of the water–oil ratio on system behavior was significant, and analogous to that of salinity. Increasing the water–oil ratio led the system change from winsor I → winsor III → winsor II. The greater the water–oil ratio the lower the salinity required to produce the middle-phase microemulsion, but the narrower the salinity range of the three-phase region. An empirical correlation has been developed in order to predict the changes in phase behavior with the changes in water–oil ratio. This provides a useful tool for designing optimum formulations suitable for soil remediation. Received: October 5, 1999 / Accepted: March 27, 2000