Remedial Operations Research Articles

Occurrence, characterization, and ecological risk analysis of petroleum hydrocarbons in water and sediments following large-scale field simulated oil spills at the experimental lakes area, Northwestern Ontario, Canada

This study assessed the impact of on-site field-simulated oil spills at the International Institute for Sustainable Development-Experimental Lakes Area (IISD-ELA) on a freshwater boreal lake. Low total petroleum hydrocarbons (TPH) values were obtained in water and sediments from the locations without direct oil loading across the 6-year monitoring program. Biogenic n-alkanes and pyrogenic polycyclic aromatic hydrocarbons (PAHs) were predominant pre- and post-spill. No petroleum biomarkers were detected in the water, but trace levels appeared in a few sediments. Most TPH and PAH levels were within acceptable limits set by the Canadian Council of Ministers of the Environment (CCME) and Ontario regulations, though some PAHs exceeded guidelines. However, the frequency of exceedances did not change significantly before and after the spill. These results suggest that the spilled oil was contained effectively during the experiment period, and the environment recovered to near-background levels afterward with appropriate precautions and remediation operations.

Thermal desorption technique to speciate mercury in carbonate, silicate, and organic-rich soils

Thermal desorption is a well-assessed technique to speciate mercury (Hg) in soils and sediments. However, the effects related to the different matrices are still not properly assessed. In this study, thermal desorption was applied to Hg-free calcite mixed with Hg standard and soils rich in carbonate and silicate minerals, as well as organic matter. Hg0, HgCl2, HgO, α-HgS, β-HgS and organo-mercuric compounds were recognized, pointing out that the soil matrix operates notable differences in terms of breakdown temperatures of the Hg-compounds and suggesting that the mineralogical composition of soil has to be investigated before applying the thermal desorption technique. Furthermore, the presence of Hg0 was carefully evaluated since, as already observed, it forms Hg2+, which increases mercury mobility in the pedological cover with important consequences for those soils contaminated and located close to decommissioned or active mining areas and/or industrial sites (e.g. chloro-alkali industries). Experimental runs were thus carried out by using carbonate-, silicate- and organic-rich soils doped with liquid Hg. It was observed that Hg0 tends to be oxidized to form Hg+ and then Hg2+ as a function of soil matrix and reaction time. Surprisingly, the oxidation rate is rather fast, since after 42 days the initial content of Hg0 is halved, thus following an exponential decay. This implies that in Hg0-polluted areas, the fate of the resulting Hg2+ can be that to: i) be adsorbed by organic matter and/or Fe–Mn–Al oxides and/or ii) feed shallow aquifers. This study is a further step ahead to understand the behavior of Hg in contaminated soils from industrial and mining areas where liquid Hg is occurring in different soil matrices and may provide useful indications for remediation operations.

Investigating the flood potential of basins to locate the implementation of remedial operations in the Siah Khor watershed using VIKOR, TOPSIS, and HEC-HMS model (case study: Siah Khor watershed-Islamabad west)

Investigating the flood potential of basins to locate the implementation of remedial operations in the Siah Khor watershed using VIKOR, TOPSIS, and HEC-HMS model (case study: Siah Khor watershed-Islamabad west)

Hole cleaning evaluation and installation spacing optimization of cuttings bed remover in extended-reach drilling

In extended-reach or long-horizontal drilling, cuttings usually deposit at the bottom of the annulus. Once cuttings accumulate to a certain thickness, complex problems such as excessive torque and drag, tubing buckling, and pipe stuck probably occur, which results in a lot of non-productive time and remedial operations. Cuttings bed remover can efficiently destroy deposited cuttings in time through hydraulic and mechanical stirring effects. This paper aims to build a method for hole cleaning evaluation and installation spacing optimization of cuttings bed remover to improve the wellbore cleaning effect. Firstly, a Computational Fluid Dynamics approach with Eulerian–Eulerian multiphase model was utilized to investigate the mechanism of cuttings transportation, and a new type of cuttings bed remover was designed. Next, an evaluation method of hole cleaning effect of remover was established. After that, the effects of several drilling parameters on hole cleaning including flow rate of drilling fluid, rotational speed of drillpipe, rate of penetration, wellbore size, rheological property of drilling fluid, and remover eccentricity on the performance of cuttings bed remover were investigated. The results demonstrate that the new type of remover with streamline blade performs better than conventional removers. The efficiency of hole cleaning is greatly improved by increasing the rotational speed of drillpipe, flow rate of drilling fluid, remover eccentricity, and 6 rpm Fann dial reading for drilling fluid. While higher rate of penetration and large wellbore size result in worse hole cleaning. These findings can serve as an important guide for the structure optimization design of cuttings bed remover and installation spacing of removers.

Critical review of the environmental management of a DNAPL contaminated site in Resende, Rio de Janeiro, Brazil

The current nonconformity of most Brazilian states regarding the environmental guidelines established by the Conama 420 resolution makes clear that there are still many challenges to be faced on the management field of contaminated sites. The analysis of a factual remediation operation in an industrial site in the city of Resende, Rio de Janeiro state, show that traditional site investigation techniques are still being applied as main tools of characterization, data collection and decision-making in the management of the area. The site has had its investigation start in the late 90’s through multiple soil sampling and monitoring wells installation, pointing DNAPLs (dense non-aqueous phase liquids) among the chemicals of interest. The industrial site has undergone remediation for over 10 years now and has not been closed yet. More recently, the efficiency reduction of the primary remediation system, a dual-phase extraction system with over 50 installed wells, led to the implementation of in-situ stimulated bioremediation. Performance reports show lower efficiency than expected, hinting that a lackluster CSM (conceptual site model) might be leading to poor decision making. Despite being adequate remediation techniques, previous efforts and literature indicate that the site must undergo new investigation steps employing high-resolution site characterization (HRSC) techniques such as the MIP (membrane interface probe), allowing the refinement of the current CSM and the optimization of current remediation efforts.

Photocatalytic Reduction of Methylene Blue by Surface-Engineered Recombinant Escherichia coli as a Whole-Cell Biocatalyst.

A novel Escherichia coli strain, created by engineering its cell surface with a cobalt-binding peptide CP1, was investigated in this study. The recombinant strain, pBAD30-YiaT-CP1, was structurally modeled to determine its cobalt-binding affinity. Furthermore, the effectiveness and specificity of pBAD30-CP1 in adsorbing and extracting cobalt from artificial wastewater polluted with the metal were investigated. The modified cells were subjected to cobalt concentrations (0.25 mM to 1 mM) and pH levels (pH 3, 5, 7, and 9). When exposed to a pH of 7 and a cobalt concentration of 1 mM, the pBAD30-CP1 strain had the best cobalt recovery efficiency, measuring 1468 mol/g DCW (Dry Cell Weight). Furthermore, pBAD30-CP1 had a higher affinity for cobalt than nickel and manganese. Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), and Energy-Dispersive X-ray Spectroscopy (EDS) were used to examine the physiochemical parameters of the recombinant cells after cobalt adsorption. These approaches revealed the presence of cobalt in a bound state on the cell surface in the form of nanoparticles. In addition, the cobalt-binding recombinant strains were used in the photocatalytic reduction of methylene blue, which resulted in a 59.52% drop in the observed percentage. This study shows that modified E. coli strains have the potential for efficient cobalt recovery and application in environmental remediation operations.

Review on NIPAH Virus

Nipah contagion is an acute febrile illness that can beget fatal encephalitis. It's an arising zoonotic paramyxovirus aboriginal to south- east Asia and the western Pacific, and can be transmitted by its primary force of fruit batons, through intermediate beast vectors and by mortal- to- mortal spread. Outbreaks of Nipah contagion encephalitis have passed in Malaysia, Singapore, Philippines, India and Bangladesh, with the most recent outbreak being in Kerala, India in late. Extremely high case casualty rates have been reported from these outbreaks, and to date no vaccines or remedial operation options are available. Combining this with its propensity to present non-specifically, Nipah contagion encephalatis present a grueling opinion that should not be missed in cases returning from aboriginal regions. Raising mindfulness of the epidemiology clinical donation and threat factors of constricting Nipah contagion is vital to honor and manage implicit outbreaks of this complaint in the UK

Evaluation of the injection and plugging ability of a novel epoxy resin in cement cracks

Sustained casing pressure (SCP) is a crucial issue in the oil and gas production lifecycle. Epoxy resins, exhibiting exceptional compressive strength, ductility, and shear bonding strength, have the potential to form reliable barriers. The injectivity and sealing capacity of the epoxy resin is crucial parameters for the success of shallow remediation operations. This study aimed to develop and assess a novel solid-free resin sealant as an alternative to Portland cement for mitigating fluid leakage. The investigation evaluated the viscosity, compressive strength, and brittleness index of the epoxy resin sealant, as well as its tangential and normal shear strengths in conjunction with casing steel. The flow characteristics and sealing abilities of conventional cement and epoxy resin were comparatively analyzed in cracks. The results showed that the application of a viscosity reducer facilitated control over the curing time of the epoxy resin, ranging from 1.5 to 6 h, and reduced the initial viscosity from 865.53 to 118.71 mPa⋅s. The mechanical properties of the epoxy resin initially increased with a rise in curing agent content before experiencing a minor decrease. The epoxy resin containing 30% curing agent exhibited optimal mechanical properties. After a 14-day curing period, the epoxy resin's compressive strength reached 81.37 MPa, 2.12 times higher than that of cement, whereas the elastic modulus of cement was 2.99 times greater than that of the epoxy resin. The brittleness index of epoxy resin is only 3.42, demonstrating high flexibility and toughness. The tangential and normal shear strengths of the epoxy resin exceeded those of cement by 3.17 and 2.82 times, respectively. In a 0.5 mm-wide crack, the injection pressure of the epoxy resin remained below 0.075 MPa, indicating superior injection and flow capabilities. Conversely, the injection pressure of cement surged dramatically to 2.61 MPa within 5 min. The breakthrough pressure of 0.5 PV epoxy resin reached 7.53 MPa, decreasing the crack's permeability to 0.02 D, a mere 9.49% of the permeability observed following cement plugging. Upon sealing a 2 mm-wide crack using epoxy resin, the maximum breakthrough pressure attained 5.47 MPa, 3.48 times of cement. These results suggest that epoxy resin sealant can be employed safely and effectively to seal cracks in the cement.

Revitalizing our earth: unleashing the power of green energy in soil remediation for a sustainable future.

This study investigates the feasibility of using renewable energy sources in soil remediation to advance green recovery in a way that is both sustainable and kind to the environment. The report stresses the need to reduce the adverse effects of soil pollution in China and foster economic recovery. This study aims to determine how green energy may be most effectively used in soil remediation operations. Using renewable energy sources to power remediation procedures and phytoremediation is presented in this research as two ways to achieve green recovery in soil remediation. The analysis in this work employs the unit root, auto-regressive distributive lag (ARDL), and vector error correction model (VECM) methods. Based on our research, we know that using renewable energy sources like solar, wind, and geothermal power may significantly lessen the environmental impact of soil remediation while simultaneously advancing the cause of sustainability. Phytoremediation is a low-cost, environmentally friendly option that utilizes plants to degrade and remove soil pollutants. The study's findings also stressed the need to consider various remediation strategies' advantages and disadvantages. The study's findings also exposed the potential advantages and disadvantages of phytoremediation, as was the method's viability for use in extensive soil remediation initiatives. The report concludes by emphasizing the need to assess soil remediation and green recovery's more enormous social and environmental implications. We can build a more sustainable future, encourage economic recovery, and combat environmental degradation using renewable energy sources and cutting-edge remediation techniques. The article suggests doing more studies to learn more about the pros and downsides of combining soil remediation and green recovery initiatives.

Progress with the regulation of radiation safety during recovery and removal of spent nuclear fuel from the site for temporary storage at Andreeva Bay on the Kola Peninsula.

In the 1960s, a shore technical base (STB) was established at Andreeva Bay on the Kola Peninsula, in northwest Russia. The STB maintained nuclear submarines and the nuclear icebreaker fleet, receiving and storing fresh and spent nuclear fuel (SNF) as well as solid and liquid radioactive waste (RW). It was subsequently re-designated as a site for temporary storage (STS) for SNF and RW. Over time, the SNF storage facilities partly lost their containment functions, leading to radioactive contamination of workshops and the site above permitted values. The technological and engineering infrastructure at the site was also significantly degraded as well as the condition of the stored SNF. At present, the STS Andreeva Bay facility is under decommissioning. This paper describes progress with the creation of safe working measures for workers involved in site remediation and SNF recovery operations, including the determination of safe shift times in high radiation areas, as part of overall optimization of safety. Results are presented for the successful application of these measures in the period 2019-2021, during which time significant SNF recovery and removal operations were completed without incident. Significant important experience has been gained to support safe removal of remaining SNF, including the most hazardous degraded fuel, as well as recovery of other higher level RW and decommissioning of the old storage buildings and structures.

MODELLING THE EFFECT OF CONTAMINATION ON THE RHEOLOGICAL PROPERTIES OF CEMENT SLURRY USING OIL-BASED MUD AS CONTAMINANT, TO IMPROVE CEMENTING JOB DESIGN AND EXECUTION IN THE OIL & GAS INDUSTRY

Cementing job failure often occurs due to cement slurry contamination with drilling mud during primary cementing and remedial cementing jobs in the oil & gas industry. The enormous consequences of cement slurry contamination with drilling mud include drastic reduction in the thickening time of cement slurry and increased rheological properties of the cement slurry due to the much more viscous resultant cement slurry/mud mixture often leading to incomplete cement job, poor mud removal, poor cement bond, gas channeling, gas kick, blow out, downtime, revenue loss and remedial cementing. The rheological properties of cement slurry and drilling mud are strongly dependent on temperature. There are also emergency situations in the oilfield where bottomhole temperature changes to a higher temperature requiring adjustments in the original cementing job design to include the new bottomhole temperature when Laboratory services are not immediately available. The aforesaid and the associated cost of remedial operations prompted this work to investigate the effect of temperature and contamination on the rheological properties of cement slurry using oil-based mud as contaminant to invent a process to better avoid cement slurry contamination and to improve cementing job designs and execution in the oil & gas industry. The methods applied include Laboratory testing and mathematical modeling. Mathematical models were developed using Microsoft Excel to predict the rheological properties of contaminated cement slurries as a function of temperature and contamination with oil-based mud as the contaminant. Results showed that the Plastic viscosity and yield stress of the contaminated cement slurries increased with temperature and extent of contamination with oil-based mud but the yield stress also decreased with extent of contamination at high temperatures. The very high regression coefficient obtained with each of the mathematical models showed that the mathematical models can be confidently applied to predict the rheological properties (Plastic viscosity and yield stress) of the contaminated cement slurries as a function of temperature and extent of contamination with the oil-based mud.

Hydrothermal Synthesis of Fe-Doped Cadmium Oxide Showed Bactericidal Behavior and Highly Efficient Visible Light Photocatalysis.

Cationic dyes present in industrial effluents significantly reduce the effectiveness of remediation operations. Considering the terrible impact of these pollutants on environment and biodiversity, investigating strategies to remove potentially harmful compounds from water is becoming an increasingly intriguing issue. In this work, we employed a simple hydrothermal technique to synthesize Fe-doped CdO (2, 4, and 6 wt %) nanostructures and assessed their efficacy in degrading methylene blue (MB) dye and inhibiting the growth of Staphylococcus aureus and Escherichia coli, respectively. Structural, morphological, and optical characterization of produced nanomaterials was also performed using X-ray diffraction, TEM, and UV absorption spectra. The photocatalytic decomposition of MB was significantly enhanced (58.8%) by using Fe (6 wt %)-doped CdO catalysts for 80 min under irradiation. In addition, 2.05-5.05 mm inhibitory zones were seen against Gram-positive bacteria (S. aureus), whereas the range for Gram-negative bacteria (E. coli) was 1.65-2.75 mm. These nanostructures were shown to be very effective inhibitors of beta-lactamase, d-alanine-d-alanine ligase B, and fatty acid synthase inhibitor by in silico molecular docking investigations.

Modeling the effect of operational activity on wellbore integrity and wellbore leakage in British Columbia

Wellbore leakage, which indicates a failure to provide hydraulic isolation downhole, is an issue facing many wells currently in production in BC. Wellbore leakage is a complex issue that is yet to be fully understood. In the work presented here, we use a previously developed stochastic model of wellbore leakage calibrated to British Columbia data, to investigate the effect of a number of operational factors on wellbore leakage. These include the height of the cement column in the annulus, the intersection of an over-pressured hydrocarbon bearing formation (above the target zone), and the use of squeeze cementing in remedial operations. These effects on leakage have not been previously investigated and our results show that each operational effect can be significant, and why. This suggests that stochastic-based models that capture the variability of the well integrity can be used to support the development of risk-based plug and abandonment (P&A) practices. We repeatedly came to the conclusion that reducing wellbore leakage is often localized, requiring an impermeable barrier be placed across the cap rock. Heterogeneity of the microannulus thickness, both azimuthally and along the well axis, can have surprising effects on the sensitivity of leakage behavior in individual wells and consequently must be accounted for in operational design.

Rapid Determination of the Total Petroleum Hydrocarbon Content of Soils by Handheld Fourier Transform Near-Infrared Spectroscopy.

For successful soil remediation and hydrocarbon exploration operations, determining the total petroleum hydrocarbon (TPH) content of soils is an indispensable process step. This paper reports on the performance of a handheld Fourier transform near-infrared (FT-NIR) spectrometer for rapid and quantitative determination of TPH content of soils from two different sites by diffuse reflection measurements. For rapid decisions for exploration work or environmental site assessment projects, a quick─preferably on-site─determination of TPH content is valuable. Diffuse reflection NIR spectra were recorded from soil samples of two different sites with TPH reference values ranging from 350 to 30,000 ppm, as determined by capillary gas chromatography and flame ionization detection with hydrocarbon fingerprinting C1-C44. However, this paper not only addresses the development of site-specific partial-least squares (PLS) calibrations but also demonstrates the locally-weighted PLS (LW-PLS) technique, which can be used to develop global, site-independent PLS calibrations without significant penalty in calibration performance. As a first step, the diffuse reflection spectra were used to develop conservative, site-specific PLS calibration models with root-mean-square calibration/cross-validation errors (RMSEC/RMSECV) of 1043/1106 and 741/785 ppm TPH, respectively, and the average absolute prediction errors for samples not contained in the calibration set were 451 and 293 ppm for the two sites, respectively. In a further step, significant degradation of the RMSE values of a conservative PLS model based on the NIR spectra of both sites was then compared to the application of the LW-PLS method, with only a slight loss of the prediction accuracy relative to the site-independent models. This study confirms the ability of next-generation portable FT-NIR spectrometers to predict low TPH levels in various soil types through both─soil-specific and site-independent─calibrations, giving these spectrometers the potential to become rapid screening tools in the field.

Study Reviews Technologies, Work Flows in Heavy Oil Reservoir Management

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 209328, “Heavy Oil Reservoir Management—Latest Technologies and Work Flows,” by Hakki Aydin, SPE, Middle East Technical University; Nirup Nagabandi, Incendium Technologies; and Cenk Temizel, SPE, Saudi Aramco, et al. The paper has not been peer reviewed. _ Successful heavy oil reservoir management practices are built on analyzing and accurately predicting reservoir behavior over time. Given the complex nature of heavy oil reservoirs, including geomechanical properties and fluid-flow behavior, a need exists to develop a repeatable technique that can account for these complexities within an acceptable margin of accuracy. The objective of the complete paper is to conduct a comprehensive review of recent technologies and work flows developed for heavy oil reservoir management that can be used as a single source of reference for the industry. Introduction Because of its comprehensive nature, much of the complete paper is dedicated to a review of the characteristics of heavy oil reservoirs and their exploitation, including thermal and nonthermal methods and the literature dedicated thereto. This synopsis will concentrate on the authors’ reviews of work flows to manage these reservoirs and field applications of the methodologies they review. Work Flow for Heavy Oil Reservoir Management Reservoir management is a multidisciplinary field involving detailed analysis of geosciences such as reservoir engineering, geological engineering, and petrophysics. Evaluation of geological information and fluid properties helps to understand the distribution of heavy oil in the reservoir. Understanding the characteristics of heavy oil reservoirs is essential for selecting the appropriate enhanced oil recovery (EOR) method. Reservoir-surveillance techniques play a critical role in understanding complex systems. Statistical approaches might be required to handle extensive data sets of production history and petrophysical data. The main goal of the reservoir management team in thermal EOR methods is to optimize parameters in steam-injection projects to maximize recovery rates from heavy oil reservoirs. The important parameters influencing the success of thermal projects include injection rates and pressures, preferential steam paths, well profiles, and reservoir depth. Previous work has presented a work flow for optimizing steamfloods in Oman. The work flow involves a review of production and injection history, petrophysical properties, and geological descriptions. Steam/oil ratio was used as a key performance indicator for steam management; it is defined as barrels of steam injected for 1 bbl of additional oil production. The steam breakthrough was monitored from the wellhead flowing temperature of the producer wells. A sudden increase in wellhead temperature is associated with a steam breakthrough. The permeability map of the reservoir helps to select appropriate injectors for a steamflood. High-permeability wells might lead to fingering, causing less recovery. Vertical conformance is desired to achieve oil sweep with steam. Observation wells are the controlling stations of steamflooding efficiency. It is critical to place the observation wells in heterogeneous reservoirs. Geophysical methods also are applied for surveillance of steam-injection projects. Real-time surveillance plays a critical role in the optimization of heavy oil reservoirs. The authors describe a modeling technique called Production Universe (PU) that enables operators to estimate oil and water production in real time. PU is effective at finding the offending well in case of sudden changes in field-level production. PU provides an automated daily production and deferment report that guides analysts to identify low-efficiency wells for remedial operations.

Remediation of contaminated sand by Cd ions with variation operation: Batch and flushing column with foam and without foam of SDS surfactant

An anionic surfactant, Sodium dodecyl sulfate (SDS), was applied to remove Cd ions as contaminants on the sand surface. The remediation operation approach was used, such as batch, flushing column without foam, and with foam of SDS solution. Increasing the SDS concentration is possible to improve the removal ability of Cd ions from the sand surface. For batch, the operation performs the higher removal ability by increasing the shaking rotation per minute (rpm). Fluctuation of the percentage removal efficiency (% RE) was shown by using a flushing column without foam at each flow rate variation. The channeling effect during flushing in the column was proved to be the cause of fluctuation in the removal efficiency. Flushing with foam is possible to increase the removal efficiency from 10% by batch and flushing without foam to about 70% with foam. The increasing flow rate of surfactant SDS solution is possible to increase the removal efficiency and flow to the intra-particle area of sand and then decrease the channeling effect. Flushing in column approach with foam by anionic surfactant SDS shows the higher ability and more efficiency in the removal of Cd ions on the sand surface.

Demonstration and evaluation of commercial and municipal equipment for urban biological decontamination.

Large-scale biological contamination incidents pose unique yet significant challenges to remediation operations. Previous incidents have demonstrated the utility of readily available commercial and municipal equipment for conducting remediation tasks. Preidentification and evaluation of such equipment could reduce lag time for response initiation and enhance overall response effectiveness and efficiency. The current study aimed to identify commercial and municipal equipment that could be beneficial in wide-area biological remediation operations. Equipment were identified by market research, their utility was assessed by a group of subject matter experts, and a subset of those equipment was observed under operational conditions in a realistic urban environment. Observations and feedback from demonstration participants are presented within the article. This information is intended to support rapid decision-making following large-scale biological incidents, broaden the universe of potentially useful equipment to support the response, enhance response operations, and reduce the impact on the public.

Proactive Self-Healing Approaches in Mobile Edge Computing: A Systematic Literature Review

The widespread use of technology has made communication technology an indispensable part of daily life. However, the present cloud infrastructure is insufficient to meet the industry’s growing demands, and multi-access edge computing (MEC) has emerged as a solution by providing real-time computation closer to the data source. Effective management of MEC is essential for providing high-quality services, and proactive self-healing is a promising approach that anticipates and executes remedial operations before faults occur. This paper aims to identify, evaluate, and synthesize studies related to proactive self-healing approaches in MEC environments. The authors conducted a systematic literature review (SLR) using four well-known digital libraries (IEEE Xplore, Web of Science, ProQuest, and Scopus) and one academic search engine (Google Scholar). The review retrieved 920 papers, and 116 primary studies were selected for in-depth analysis. The SLR results are categorized into edge resource management methods and self-healing methods and approaches in MEC. The paper highlights the challenges and open issues in MEC, such as offloading task decisions, resource allocation, and security issues, such as infrastructure and cyber attacks. Finally, the paper suggests future work based on the SLR findings.

The contaminated sites in the SENTIERI Project: an update of legislative, contamination, and sources of environmental exposure aspects in Italy

In Italy, the problem of contaminated sites was introduced for the first time at a regulatory level with the 'Ronchi Decree' No. 22 of 1997. Subsequently, the regulations that defined most of the contaminated Sites of National Interest (SINs) were Law No. 426 of 09.12.1998 and Law no. 179 of 31.07.2002. Today, the reference directive is the Legislative Decree 152/2006 'Consolidated Environmental Act', which in Part IV, Title V 'Remediation of contaminated sites', dictates the administrative and technical procedures for the remediation of contaminated sites. Over time, there have been numerous regulatory updates that have changed the selection criteria for the SINs, leading some of these to be downgraded to Sites of Regional Interest (SIRs). The SINs in their entirety are managed by the Italian Ministry of the Environment, today called 'of the Ecological Transition', while the pass to the competence of the territorially concerned Regions SIRs regarding the verification and eventual remediation operations. Currently, in Italy there are 42 SINs and 17 SIRs. All the information derived from the various environmental regulations and that found in the context of the remediation procedures made it possible to define the exposure of the population residing in the areas adjacent to the SINs and SIRs as well as the elaboration of sheets containing all the site-specific information.

Prediction of 1,4-Dioxane Migration in Groundwater and Evaluation of Remediation Measures in an Illegal Dumping Site Using a 2D-Numerical Model

Illegal dumping sites are usually characterized by complex contamination situations due to the presence of multiple contamination sources. To improve the efficiency of illegal waste dumping site remediation, this study developed a numerical model considering the effects of groundwater levels and hydraulic gradient changes on remediation operations. Using this model, the most likely sources of contamination for 1,4-dioxane at an illegal waste site in Iwate Prefecture, Japan, were successfully identified (including location, amount, and time of occurrence) by reproducing historical monitoring data (from 2010 to 2022) through history matching, and future contaminant migration in groundwater was predicted. In addition, based on quantitative evaluations of the remediation measures, we found that some remediation measures, such as impermeable wall construction, while having some effects on the control of contamination spreading, may accelerate the migration of contaminants off-site due to the change of hydraulic gradient. Therefore, remediation procedures should be more carefully considered for illegal dumping sites based on an understanding of the distribution of contamination sources and hydraulic gradient evolutions.