Reactive Organic Suspensions Comprising ZnO, TiO2, and Zeolite Nanosized Adsorbents: Evaluation of Decontamination Efficiency on Soman and Sulfur Mustard

This paper comprises an extensive study on the evaluation of decontamination efficiency of three types of reactive organic suspensions (based on nanosized adsorbents) on two real chemical warfare agents: soman (GD) and sulfur mustard (HD). Three types of nanoparticles (ZnO, TiO2, and zeolite) were employed in the decontamination formulations, for enhancing the degradation of the toxic agents. The efficacy of each decontamination solution was investigated by means of GC-MS analysis, considering the initial concentration of toxic agent and the residual toxic concentration, measured at different time intervals, until the completion of the decontamination process. The conversion of the two chemical warfare agents (HD and GD) into their decontamination products was also monitored for 24 h.

Mercury Contamination of Process and Pipeline Infrastructure - A Novel, All- Encompassing Solution for the Evaluation and Decontamination of Mercury from Pipelines and Topside Process Equipment to allow Safe Disposal

Mercury present in produced oil and gas will deposit onto the internal process infrastructure via a number of mechanisms including chemisorption and adsorption with the primary mechanism being through reaction with iron sulphide to form mercury sulphide. Due to the volumes of fluids produced and the length of time facilities are in production, even where the produced fluids have historically contained relatively low concentrations of mercury, pipeline scales containing percentage levels of mercury may be present. Thus, aged facilities and infrastructure that have reached the end of their operational life and are selected for either recycling or abandonment, may pose a serious risk to health and the environment if the decommissioning process is not managed correctly. Smelting, hot cutting or other thermal/abrasive surface preparations for example, can lead to significant release of elemental mercury, a worker exposure hazard. Alternatively, if sub-sea pipelines are abandoned in-situ, all mercury present will ultimately be transferred to the local ecosystems. Consequently, the oil and gas industry have the requirement for a complete mercury decontamination solution from initial evaluation, demonstrable cleaning efficacy through to a guarantee for the treatment and disposal of the mercury waste generated in an environmentally-friendly manner. In order to decide upon the most appropriate decontamination solution, an evaluation of the extent of mercury contamination should be undertaken. A novel approach that has recently been successfully implemented involved analysis of pipe sections by multiple analytical techniques, providing the mercury concentration in the scale/steel. From this, the total mass of mercury across the process or pipeline was approximated. Subsequently, the efficacy of the preferred chemical to remove mercury from the internal surfaces of pipework was evaluated by chemical treatment of the pipe sections under laboratory conditions. In-situ decontamination can be performed by a number of applications, including (i) the use of chemical pig trains in pipelines, (ii) closed loop circulation of chemical around topside process equipment and (iii) high pressure spraying of large surface areas such as storage tanks, FSO / FPSO vessels. The mercury waste generated is treated, on site or off site, to minimise the volume and disposed of in accordance with international regulations. An all-encompassing mercury decontamination solution is described. Trials involving the chemical treatment of steel sections have demonstrated that more than 97% of the mercury deposited can be removed from the internal surfaces of pipelines and safely disposed of, significantly reducing the risk of (i) mercury release to the environment and (ii) worker exposure to mercury during smelting activities.

Refinment of a decontamination technology for radioactively contaminated equipment

This article analyzes the data on chemical decontamination methods dealing with radioactively contaminated surfaces. It considers the composition of solutions most commonly used for decontamination purposes. Numerical data are presented to illustrate the effectiveness of various decontamination methods. The paper considers an experiment on the decontamination of stainless steel samples with water following a cavitation treatment. The study reveals a dependence between the decontamination efficiency and the treatment time of the contaminated surface with a decontamination solution based on cavitation-activated water, which appears to be comparable with the results of the one involving an alkaline solution.

Selective digestive decontamination solution used as “lock therapy” prevents and eradicates bacterial biofilm in an in vitro bench-top model

Background Most preventing measures for reducing ventilator-associated pneumonia (VAP) are based mainly on the decolonization of the internal surface of the endotracheal tubes (ETTs). However, it has been demonstrated that bacterial biofilm can also be formed on the external surface of ETTs. Our objective was to test in vitro the efficacy of selective digestive decontamination solution (SDDs) onto ETT to prevent biofilm formation and eradicate preformed biofilms of three different microorganisms of VAP. Methods We used an in vitro model in which we applied, at the subglottic space of ETT, biofilms of either P. aeruginosa ATCC 15442, or E. coli ATCC 25922, or S. aureus ATCC 29213, and the SDDs at the same time (prophylaxis) or after 72 h of biofilm forming (treatment). ETT were incubated during 5 days with a regimen of 2 h-locks. ETT fragments were analyzed by sonication and confocal laser scanning microscopy to calculate the percentage reduction of cfu and viable cells, respectively. Results Median (IQR) percentage reduction of live cells and cfu/ml counts after treatment were, respectively, 53.2% (39.4%—64.1%) and 100% (100%–100.0%) for P. aeruginosa, and 67.9% (46.7%–78.7%) and 100% (100%–100.0%) for E. coli. S. aureus presented a complete eradication by both methods. After prophylaxis, there were absence of live cells and cfu/ml counts for all microorganisms. Conclusions SDDs used as “lock therapy” in the subglottic space is a promising prophylactic approach that could be used in combination with the oro-digestive decontamination procedure in the prevention of VAP.

Screening anti-infectious molecules against Mycobacterium ulcerans: a step towards decontaminating environmental specimens

Mycobacterium ulcerans, a non-tuberculous mycobacterium responsible for Buruli ulcer, is residing in poorly defined environmental niches in the vicinity of stagnant water points where very few isolates have been confirmed. In the perspective of culturing M. ulcerans from such contaminated environmental specimens, we tested the in vitro susceptibility of M. ulcerans CU001 strain co-cultivated with XTC cells to anti-infectious molecules registered in the French pharmacopoeia, using a standardised concentration, to find-out molecules inactive against M. ulcerans which could be incorporated in decontaminating solution. Of 116 tested molecules, 64 (55.1%] molecules including 34 (29.3%] antibiotics, 14 (12%] antivirals, 8 (6.8%] antiparasitic and 8 (6.8%] antifungals were ineffective against M. ulcerans CU001; leaving 52 molecules active against M. ulcerans CU001. Three such inactive antimicrobial molecules (oxytetracycline, polymyxin E and voriconazole] were then selected to make a decontamination solution shown to respect M. ulcerans CU001 viability. These three antimicrobials could be incorporated into a decontamination solution for the tentative isolation and culture of M. ulcerans from environmental samples.