Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Remediation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 109 records · Page 6Linked to original sources
PubMed2004

A review of NAPL source zone remediation efficiency and the mass flux approach.

A number of previous studies are reviewed to examine the actual reduction of NAPL from source zones and the effectiveness of the specific technique of remediation used at sites under study. It has been shown that complete removal of the NAPL in free phase or residual is not possible due to the complex entrapment architecture of NAPLs at field sites. Consequently, the assessment of remediation efficiency should not be solely based on the reduction of entrapped NAPL mass from source zone. Instead, it should be based on the reduction of risk achieved through the lowering of the concentration of the dissolved constituents emanating from the entrapped NAPL during source zone clean-up. The prediction of the concentration in the plume requires a knowledge of the dissolution of NAPLs in the source zone. Attention is directed to the need for the understanding the mass transfer from entrapped NAPLs in the source zone before and after remediation. In this paper, the current knowledge of mass transfer processes from the non-aqueous phase to the aqueous phase is summarised and the use of mass flux measurements (monitoring the concentration of contaminants in aqueous phase due to source zone NAPL-groundwater mass transfer) is introduced as a potential tool to assess the efficiency of technologies used in source zone remediation. Preliminary results of numerical simulations reveal that factors such as source zone morphology as determined by the heterogeneity of the formation control the post-remediation dissolution behaviour, than the local mass transfer. Thus, accurate site characterization is essential for predicting NAPL dissolution and mass flux relationships as well as for assigning site-specific remediation target values.

Evaluation Studies as Topic↗
PubMed2001

Geochemical investigations of sulfide-bearing tailings at Kristineberg, northern Sweden, a few years after remediation.

In the Kristineberg mining area in northern Sweden, massive, pyrite-rich Zn Cu ores are intercalated in ca. 1.9 Ga volcano-sedimentary rocks. Investigations of a tailings impoundment remediated by means of both till coverage and raising the groundwater table have been undertaken. The aim of the study was to characterise the tailings with respect to mineralogy, the chemical composition of both the tailings and the pore water, and to try to identify the significant reactions that may have occurred before and after remediation. It was found that the oxidation front had reached down to depths of between approximately 0.1 and 1.15 m before remediation. The oxidation of sulfides has produced high concentrations of some metals in the pore water; up to 26, 16, 4.1, 2.7 and 82 mg/l have been measured for Al, Mn, Fe and Zn, respectively. Concentrations of metals such as Cd, Co, Cu, Ni and Pb are lower, with average concentrations of 18.4, 83.8, 45, 79.6 and 451 microg/l, respectively. Higher concentrations of major elements such as Ca, Fe, Mn, Mg and S have been measured at depth in pore water than at shallower levels. This is probably caused by flush out of elements after remediation and vertical transport from the upper parts before remediation. The pH is relatively high, approximately 5.5 at most depths in the tailings, except in and around the former oxidation zone where it is lower, and where the highest dissolved concentrations of elements such as As, Cd, Co, Cu, Pb and Zn occur. This is probably due to the release of metals secondarily retained below the oxidation front prior to the remediation. Since the groundwater table is raised, the groundwater reaches the retained metals, which leads to desorption of metals and dissolution of secondary minerals.

Environmental Monitoring↗
PubMed2002

Bench-scale visualization of DNAPL remediation processes in analog heterogeneous aquifers: surfactant floods and in situ oxidation using permanganate.

We have conducted well-controlled DNAPL remediation experiments within a 2-D, glass-walled, sand-filled chamber using surfactants (Aerosol MA and Tween 80) to increase solubility and an oxidant (permanganate) to chemically degrade the DNAPL. Initial conditions for each remediation experiment were created by injecting DNAPL as a point source at the top of the chamber and allowing the DNAPL to migrate downward through a water-filled, heterogeneous, sand-pack designed to be evocative of a fluvial depositional environment. This migration process resulted in the DNAPL residing as a series of descending pools. Lateral advection across the chamber was used to introduce the remedial fluids. Photographs and digital image analysis illustrate interactions between the introduced fluids and the DNAPL. In the surfactant experiments, we found that DNAPL configured in a series of pools was easily mobilized. Extreme reductions in DNAPL/water interfacial tension occurred when using the Aerosol MA surfactant, resulting in mobilization into low permeability regions and thus confounding the remediation process. More modest reductions in interfacial tension occurred when using the Tween 80 surfactant resulting in modest mobilization. In this experiment, capillary forces remained sufficient to exclude DNAPL migration into low permeability regions allowing the excellent solubilizing properties of the surfactant to recover almost 90% of the DNAPL within 8.6 pore volumes. Injection of a potassium permanganate solution resulted in precipitation of MnO2, a reaction product, creating a low-permeability rind surrounding the DNAPL pools. Formation of this rind hindered contact between the permanganate and the DNAPL, limiting the effectiveness of the remediation. From these experiments, we see the value of performing visualization experiments to evaluate the performance of proposed techniques for DNAPL remediation.

Adsorption↗
PubMed2002

A critical comparison of the cost-effectiveness of domestic radon remediation programmes in three counties of England.

Radon remediation programmes in domestic dwellings were carried out in five areas, from three counties of England, and the total costs obtained. A single company, which abided by the Code of Practice of the Radon Council of Great Britain, carried out the remediation. The dose savings from the programmes were calculated and used to estimate the number of lung cancers averted. The data obtained allowed the cost-effectiveness of the remediation programmes in each area to be calculated. The remediation programmes in three areas (Northants 2, 3 and North Oxfordshire) were cost-effective whereas those in two areas (Northants 1 and North Somerset) were not. To be cost-effective, the Northants I and North Somerset areas would need to increase the number of householders that carried out remediation, if they were over the UK Action Level. Health policy makers should concentrate their resources on communities in areas where there is a significant proportion of dwellings above the UK Action Level and where the number of properties being remediated is low.

Air Pollution, Indoor↗
PubMed2002

Effects of pure and dyed PCE on physical and interfacial properties of remedial solutions.

Hydrophobic dyes have been used to visually distinguish dense non-aqueous phase liquid (DNAPL) contaminants from background aqueous phases and soils. The objective of this study was to evaluate the effects of a dyed DNAPL, 0.5 g Oil-Red-O/l of PCE, on the physical properties of remedial solutions: water, co-solvents (50, 70, and 90% (v/v) ethanol), and surfactants (4% (w) sodium dihexyl sulfosuccinate). This study compared the densities, viscosities, and interfacial tensions (IFTs) of the remedial solutions in contact with both dyed and undyed PCE. The presence of the dye in PCE substantially alters the IFTs of water and ethanol solutions, while there is no apparent difference in IFTs of surfactant solutions. The remedial solutions saturated with PCE showed higher viscosities and densities than pure remedial solutions. Solutions with high ethanol content exhibited the largest increases in liquid density. Because physical properties affect the flow of the remedial solutions in porous media, experiments using dyed DNAPLs should assess the influence of dyes on fluid and interfacial properties prior to remediation process analysis.

Azo Compounds↗
PubMed2002

Some herbal remedies from Manzini region of Swaziland.

In this paper, recipes for 41 herbal remedies used for treating 25 illnesses in traditional medicine in Swaziland are reported. Preparation of the herbal remedies involved the use of different parts of 47 species from 32 families, some of which have never been described previously in the flora of Swaziland. Descriptions of the plants used, the preparation of each remedy, dosage, route of administration and medical uses are reported. Some of the diseases the remedies are used to treat include asthma, backache, candidiasis, cardiac problems, cough, diarrhoea, dizziness, eye problems, constipation, menorrhagia, painful shoulders, scabies, threatened abortion, toothache, ulcers and vomiting among others. The remedies were obtained from traditional medical practitioners (TMPs) in an ethnomedical survey carried out in the Manzini region of Swaziland. Voucher samples of the plants used for the remedies were collected, identified and deposited in the National Herbarium of Swaziland.

Eswatini↗
PubMed2003

Selective remediation of contaminated sites using a two-level multiphase strategy and geostatistics.

Selective soil remediation aims to reduce costs by cleaning only the fraction of an exposure unit (EU) necessary to lower the average concentration below the regulatory threshold. This approach requires a prior stratification of each EU into smaller remediation units (RU) which are then selected according to various criteria. This paper presents a geostatistical framework to account for uncertainties attached to both RU and EU average concentrations in selective remediation. The selection of RUs is based on their impact on the postremediation probability for the EU average concentration to exceed the regulatory threshold, which is assessed using geostatistical stochastic simulation. Application of the technique to a set of 600 dioxin concentrations collected at Piazza Road EPA Superfund site in Missouri shows a substantial decrease in the number of RU remediated compared with single phase remediation. The lower remediation costs achieved by the new strategy are obtained to the detriment of a higher risk of false negatives, yet for this data set this risk remains below the 5% rate set by EPA region 7.

Cost Control↗
PubMed2004

Remediation process monitoring of PAH-contaminated soils using laser-induced fluorescence.

In order to investigate the feasibility of Laser-Induced Fluorescence (LIF) for soil remediation process monitoring, the variation in the LIF intensity was studied, in relation to the moisture content and soil particle size distribution for different soil conditions. For each set of conditions, significant correlation was shown between the level of Polycyclic Aromatic Hydrocarbon (PAH) and the LIF intensity (R2 > 0.97). Higher fluorescence intensities were measured for PAH contaminated soils with higher sand and moisture contents. The results of the LIF monitoring for the remediation process were compared with the traditional High Pressure Liquid Chromatography (HPLC) results, after applying a surfactant-enhanced electrokinetic process for the remediation of PAH-contaminated soils. In the electrokinetic (EK) process cell. the PAH concentration, and the normalized LIF intensity near the anode and cathode, showed somewhat contrary trends with respect to the degree of the remediation, even though significantly similar trends were observed in the middle of the soil cell. This may be interpreted as the EK remediation advances, as the electro osmotic flow induce a different moisture and silt/clay, or sand, distribution throughout the soil media, which in turn influences the LIF intensity of the soils. Therefore, in order to overcome these differences, the corrected LIF intensity, using the diffuse reflectance, was applied, which showed a similar remediation trend for the soil specimens in the electrokinetic process cell.

Aluminum Silicates↗
PubMed2001

Sociodemographic and health behaviour factors among dietary supplement and natural remedy users.

OBJECTIVE: To investigate which subgroups of the Swedish adult population use dietary supplements and natural remedies, taking into account sociodemographic and health behaviour factors. DESIGN: A cross-sectional survey conducted in 1996/1997 by Statistics Sweden was used for the analyses. In face-to-face interviews participants reported consumption of dietary supplements and natural remedies during the previous 2 weeks. SETTING: Sweden SUBJECTS: A nationally representative sample of 11 422 adults (5596 men, 5826 women) aged 16-84 y. The response rate was 78%. RESULTS: Overall, 33% of Swedish women and 22% of Swedish men reported use of dietary supplements; prevalence of natural remedy users was 14 and 7%, respectively. The best predictors for use of dietary supplements and natural remedies were age, sex and subjective health. Women and older individuals were more likely to be dietary supplement and/or natural remedy users. Obese men and women were less likely to use dietary supplements than underweight ones. Among men subjective health was significantly related to use of these preparations. Men who reported excellent health ate less than men reporting poor health. This association was weaker among women. Exercise was another important factor. Both men and women (except female dietary supplement users) who reported moderate or heavy exercise were significantly more frequent users of these preparations than those who reported practically no exercise. CONCLUSION: Use of dietary supplements and natural remedies is associated with several sociodemographic and health behaviour factors. SPONSORSHIP: Karolinska Institutet Research Fund.

Adolescent↗
PubMed2001

Use of dietary supplements and natural remedies increased dramatically during the 1990s.

OBJECTIVES: To estimate the prevalence and trends in dietary supplement and natural remedy use in Sweden during the 1980s and 1990s. DESIGN: Three nationally representative, cross-sectional surveys conducted in 1980-81, 1988-89 and 1996-97 were used for analysis. In face-to-face interviews participants reported consumption of dietary supplements and natural remedies during the previous 2 weeks. SETTING: Sweden. SUBJECTS: The samples consisted totally of 38 594 adults aged 16-84 years (14 642 in the 1980-81 survey, 12 391 in the 1988-89 survey and 11 561 in the 1996-97 survey). Main outcome measures. Changes in prevalence of dietary supplement and natural remedy users between 1980 and 1997. RESULTS: The 70% increase in the prevalence of dietary supplement users amongst both men and women [odds ratio (OR), 1.7; 95% confidence interval (CI), 1.6-1.9, OR, 1.7; 95% CI, 1.5-1.8, respectively] occurred mainly between 1988-89 and 1996-97. The increase in the prevalence of natural remedy users was even more dramatic - more than threefold in men (OR, 3.3; 95% CI, 2.9-4.0) and almost threefold in women (OR, 2.6; 95% CI, 2.3-2.9) - and the systematic increase started already in the 1980s. The increase was observed in all age groups and in all socio-economic groups, except for farmers. In 1996-97 the prevalence of dietary supplement users was 22% amongst men and 33% amongst women, and of natural remedies 7 and 14%, respectively. CONCLUSIONS: During the last two decades, the use of dietary supplements and natural remedies amongst the adult Swedish population has dramatically increased.

Adolescent↗
PubMed2005

Effects of Korean traditional herbal remedy on heart rate variability: linear and nonlinear analysis.

Heart rate variability was compared in 20 subjects taking traditional herbal remedy (Ondamtanggamibang) or placebo control pill, in placebo controlled design experiment. Herbal remedy group reported more pleasant and clam emotions than did the placebo group. Herbal remedy reduced the heart rate and increased heart rate variability (HRV) as indicated by a reduced low frequency/high frequency power ratio of heart rate variability. With nonlinear analysis, the Poincaré plot index of HRV and approximate entropy was greater in the herbal remedy group than in the control group. These findings suggest that herbal remedy stabilizes the sympathovagal function and cardiac autonomic nervous system by inducing more positive emotions than does placebo therapy. In conclusion, herbal remedy may act by stabilizing both the autonomic nervous system and the emotional state.

Adult↗
PubMed1989

The superfund remedial action decision process: a review of fifty records of decision.

Although the Superfund remedial action decision process is a complex process involving a variety of technical, political, and public health issues, the primary goal of remedial action is the protection of public health. We performed an in-depth analysis of 50 post-SARA Records of Decision in order to characterize the role of risk assessment in the decision-making process and determine whether decisions are being made in an effective and environmentally protective manner. Our findings indicate that the majority of decisions to remediate Superfund sites are based on the existence of contamination per se and not on actual public health risk. Although hypothetical risk is an essential consideration, this gray area is not well-defined in the current decision-making process. The lack of assessment of the degree of risk reduction associated with the remedial alternatives evaluated and the lack of support indicating the effectiveness of the remedial alternatives selected also constitute major weaknesses in the majority of decisions. These inadequacies undermine rationales regarding the protectiveness and cost-effectiveness of the remedial alternatives selected. The fact that objectives beyond addressing public health risk are often unclear in the decision-making process also weakens rationales for cost-effectiveness.

Environmental Pollution↗
PubMed2001

Practical methods for meeting remediation goals at hazardous waste sites.

Risk-based cleanup goals or preliminary remediation goals (PRGs) are established at hazardous waste sites when contaminant concentrations in air, soil, surface water, or groundwater exceed specified acceptable risk levels. When derived in accordance with the Environmental Protection Agency's risk assessment guidance, the PRG is intended to represent the average contaminant concentration within an exposure unit area that is left on the site following remediation. The PRG, however, frequently has been used inconsistently at Superfund sites with a number of remediation decisions using the PRG as a not-to-exceed concentration (NTEC). Such misapplications could result in overly conservative and unnecessarily costly remedial actions. The PRG should be applied in remedial actions in the same manner in which it was generated. Statistical methods, such as Bower's Confidence Response Goal, and mathematical methods such as "iterative removal of hot spots," are available to assist in the development of NTECs that ensure the average postremediation contaminant concentration is at or below the PRG. These NTECs can provide the risk manager with a more practical cleanup goal. In addition, an acute PRG can be developed to ensure that contaminant concentrations left on-site following remediation are not so high as to pose an acute or short-term health risk if excessive exposure to small areas of the site should occur. A case study demonstrates cost savings of five to ten times associated with the more scientifically sound use of the PRG as a postremediation site average, and development of a separate NTEC and acute PRG based on the methods referenced in this article.

Journal Article↗
PubMed2001

Evaluation of the physical hazards associated with two remedial alternatives at a Superfund site.

This study presents an evaluation of the risks due to the physical hazards associated with two remedial alternatives for a former chemical manufacturing facility in New Jersey. Both the on-site and off-site risk of work-related fatalities during remedy implementation and the risks of accident or accident-related fatalities during the off-site transport of site-related materials were evaluated. The two remedial alternatives evaluated were on-site containment and excavation with off-site incineration. The risk of at least one fatality due to a work-related accident was estimated for on-site activities associated with each remedial alternative, and for off-site incineration. The risks of at least one accident and of one accident-related fatality were calculated with accident and fatality data from the U.S. Department of Transportation. In addition, the risk of at least one accident that might potentially affect a natural resource (e.g., river, lake, or national park) was evaluated. This evaluation indicates that the risk of a work-related fatality is over an order of magnitude higher, and the risk of an accident or accident-related fatality is over three orders of magnitude higher, for the excavation/off-site incineration remedial alternative than for the on-site containment alternative. Overall, this study indicates that the physical hazards associated with excavation and off-site incineration are much greater than those associated with on-site containment for this site. Therefore, if a choice between the two remedial alternatives were to be made based solely on physical hazards and accident risk, the on-site containment alternative would be more protective of human health and the environment than the excavation/off-site incineration alternative.

Accidents, Occupational↗
PubMed2004

[Natural remedies during pregnancy and lactation].

Up to date there is a lack of systematically gathered data on the use of natural remedies (phytotherapeutic, homeopathic, anthroposophic, spagyric, Bach and Schussler remedies) during pregnancy and lactation. The aim of this non-representative pilot study on 139 women, who came for delivery to three institutions between mid-1997 and the beginning of 1998, was to receive data about how often and within which spectrum natural remedies are used during pregnancy and lactation. During pregnancy 96% and within the lactation period 84% of the women consumed at least 1 natural remedy. Phytotherapeutic drugs were used most frequently. In contrast to the widespread use of natural remedies by pregnant women and nursing mothers in this study, little information on the effectiveness and possible risks is available. Therefore it seems necessary to examine and evaluate natural remedies used during pregnancy and lactation.

Beverages↗
PubMed1997

Traditional remedies and food supplements. A 5-year toxicological study (1991-1995).

Since 1991, the Medical Toxicology Unit (MTU) at Guys' Hospital, London, has been assessing the toxicological problems associated with the use of traditional and herbal remedies and dietary supplements. This assessment was carried out by evaluating reports to the National Poisons Information Service (London) [NPIS(L)] which provides emergency information to medical professionals. Relevant telephone enquiries to NPIS(L) were identified. Further case details were obtained by follow-up questionnaire, clinical consultation, toxicological analysis of samples from patients and/or products and botanical identification of plant material. Of 1297 symptomatic enquiries evaluated there was a possible/confirmed association in 785 cases. Case series have been identified which substantiate previous reports, including liver problems following the use of Chinese herbal medicine for skin disorders, allergic reactions to royal jelly and propolis and heavy metal poisoning caused by remedies from the Indian subcontinent. Although the overall risk to public health appears to be low, certain groups of traditional remedies have been associated with a number of potentially serious adverse effects. Considering the extent of use of herbal remedies and food supplements a comprehensive surveillance system for monitoring the adverse health effects of these products is essential. Surveillance of a large population is needed for the complex task of identifying the uncommon and unpredictable adverse effects which are potentially serious. In the UK, the Medicines Control Agency responded to the MTU report by recognising the need for vigilance and by incorporating adverse reactions reporting on unlicensed herbal remedies into their drug reaction monitoring function. As a further step to safeguard the patients/consumers an effective single regulatory system is required which would ensure the safety and quality of all herbal remedies and food supplements available in the UK.

Amino Acids↗
PubMed1992

New survey process expands sanctions. HCFA proposes more enforcement remedies and broader disclosure requirements for nursing facilities.

The Health Care Financing Administration (HCFA) has proposed a new process for surveying and certifying nursing facilities for participation in Medicare and Medicaid. The process would be grounded in the principle that all federal requirements must be met and enforced. Surveyors would use a severity and scope scale to evaluate a deficiency's seriousness and determine the appropriate corrective remedy. The more severe or pervasive the facility's shortcomings, the harsher the sanction. HCFA and the states have been reluctant to use the traditional remedy for noncompliant facilities--terminating their participation in Medicare or Medicaid. The available remedies would be expanded to include intermediate sanctions such as temporary management, denial of payment, directed plan of correction, and civil money penalties. The critical factors for determining the remedy would be the severity and scope of the deficiencies and whether they pose an immediate and serious threat to resident well-being. A facility could appeal the specific remedy, but not the conclusion that violations have occurred. Importantly, except for civil money penalties, the states would have to impose enforcement remedies at the time violations are uncovered, regardless of any other provision of state law, such as a policy precluding penalties while a hearing is pending. The proposed regulations also would impose two new notification requirements on nursing facilities--one for any facility that receives a nursing staff waiver, and the other for a facility rendering substandard care.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed2002

[Secret remedies in France until abolition in 1926].

Secret remedies are preparations or medicines whose composition is not disclosed by the inventor in order to protect his invention or to deceive the public. Secret remedies have always existed. From time immemorial the communities of apothecaries in Paris or in the provinces were opposed to quack doctors or healers who sold inactive mixtures. The 1352 Royal Edict forbade preparations of secret remedies. However, in the 17th century secret remedies were authorized through commission letters or warrants. In the 18th century regulations were implemented to control secret trade. The famous 11 April 1803 Law called the Germinal Law banned the sale of secret remedies but its severity was softened through successive decrees based on divergent interpretations of the regulations. The final banning of secret remedies was pronounced by a decree on 13 July 1926.

France↗