Association of polypharmacy with incidence of CKD: a retrospective cohort study.

BACKGROUND: Polypharmacy is common in patients with chronic kidney disease (CKD) and is associated with a decline in kidney function. However, its impact on patients without CKD has not been adequately elucidated. Therefore, we aimed to investigate the association between polypharmacy and the incidence of CKD. METHODS: We conducted retrospective cohort study using 1221 participants who were enrolled in the Fukushima Cohort Study with one or more risk factors of CKD, an estimated glomerular filtration rate (eGFR) of ≥ 60 mL/min/1.73 m2, and without proteinuria. Participants were categorized into three groups based on the number of medications: non-polypharmacy, 0-4 medications; polypharmacy, 5-9 medications; and hyper-polypharmacy, ≥ 10 medications. RESULTS: The median age was 62 years, 49% were men, the median eGFR was 75.4 ml/min/1.73 m2, and the median number of medications was 5. Polypharmacy and hyper-polypharmacy were noted in 506 (41%) and 250 (20%) participants, respectively. During follow-up, 288 participants developed CKD and 67 cardiovascular events were observed. Compared to the non-polypharmacy group, the hyper-polypharmacy group had a higher risk of CKD and cardiovascular events. The adjusted hazard ratios were 1.41 (95% CI1.01-1.99) and 2.24 (95% CI1.05-4.78) for the incidence of CKD and cardiovascular events, respectively. Sensitivity analyses yielded similar findings for the restricted cubic spline function models. CONCLUSIONS: Hyper-polypharmacy is associated with a higher risk of CKD and cardiovascular events.

Hematological parameters of anemia and prognosis of non-dialysis-dependent chronic kidney disease: the Fukushima CKD cohort study.

BACKGROUND: Mean corpuscular volume (MCV) and red cell distribution width (RDW), as well hemoglobin, are reported to be associated with mortality in various populations. However, associations between such hematological parameters and adverse outcomes in patients with CKD have not been sufficiently elucidated. METHODS: A total of 1,320 participants enrolled in the Fukushima CKD Cohort Study were examined to investigate associations between hematological parameters of anemia (MCV and RDW) and adverse outcomes, such as ESKD, all-cause death, and cardiovascular events, in patients with non-dialysis-dependent CKD. Baseline hematological parameters were grouped as follows: hemoglobin into 3 categories (< 11.0 g/dL, 11.0 ≤ - < 13.0 g/dL [reference], and ≥ 13.0 g/dL); MCV into 5 categories (< 90 fL, ≥ 90 - < 94 fL [reference], ≥ 94 - < 98 fL, ≥ 98 - < 102 fL, and ≥ 102 fL); and RDW into 2 categories (< 13.6% [reference] vs ≥ 13.6%). RESULTS: During the median observational period of 4.7 years, 120 patients developed ESKD, 160 developed cardiovascular events, and 122 died. Hemoglobin < 11 g/dL (hazard ratio [HR] 1.56, 95% confidence interval [CI], 1.00-2.42), MCV < 90 fL (HR 2.01, 95% CI 1.14-3.54), and RDW ≥ 13.6% (HR 1.57, 95% CI 1.01-2.42) were significantly associated with higher risks of ESKD. Hemoglobin < 11 g/dL, MCV ≥ 98 fL, and RDW ≥ 13.6% were significantly associated with higher risks of all-cause death. No significant associations between hematological parameters and risk of cardiovascular events were confirmed. CONCLUSION: In patients with non-dialysis-dependent CKD, MCV, RDW, and hemoglobin were associated with increased risks of ESKD and all-cause mortality.

Association between serum potassium levels and adverse outcomes in chronic kidney disease: the Fukushima CKD cohort study.

BACKGROUND: Serum potassium disorders, commonly observed in chronic kidney disease (CKD), are reportedly associated with higher mortality, but their impact on renal outcomes is still controversial. METHODS: The present study used the longitudinal data of the Fukushima CKD cohort study to investigate the relationships between hypokalemia and hyperkalemia and adverse outcomes such as renal outcomes and all-cause mortality in Japanese patients with non-dialysis-dependent CKD. The study involved 1330 CKD patients followed-up for 2.8 years. The primary endpoint of the present study was a kidney event, defined as a combination of doubling of baseline serum creatinine and end-stage kidney disease. RESULTS: Hyperkalemia (≥ 5.0 mmol/L) was noted in 10.6% and hypokalemia (< 4.0 mmol/L) in 16.4% of the study population. Significant U-shaped associations were observed between potassium levels and both kidney events and all-cause mortality on univariate Cox regression analyses. After adjustment for covariates, both hypokalemia and hyperkalemia were significantly associated with an increased risk of kidney events, with the lowest risk at a serum potassium of 4.0-4.4 mmol/L. Compared with a reference level of 4.0-4.4 mmol/L, the adjusted hazard ratio for kidney events was 2.49 (1.33-4.66) for serum potassium < 4.0 mmol/L, 1.72 (1.00-2.96) for 4.5-4.9 mmol/L, and 2.16 (1.15-4.06) for ≥ 5.0 mmol/L. There was no significant association between serum potassium levels and mortality after multivariate adjustment. CONCLUSION: Hypokalemia and hyperkalemia were associated with an increased risk of CKD progression, but not with mortality in Japanese patients with non-dialysis-dependent CKD.

Blood pressure control in chronic kidney disease according to underlying renal disease: the Fukushima CKD cohort.

BACKGROUND: Inadequate blood pressure control is one of the important causes of chronic kidney disease (CKD), but only a limited number of reports have examined blood pressure control in Japanese patients with pre-dialysis CKD. Differences in blood pressure control due to underlying renal disease in pre-dialysis patients with CKD were investigated in the present study using the baseline data of the Fukushima CKD cohort study. METHODS: The study involved 1351 CKD patients, classified by underlying disease of primary renal disease, hypertensive nephropathy, diabetic nephropathy, other nephropathies, or unknown. Target blood pressure of CKD patients was defined as < 130/80 mmHg in patients under 75 years old with diabetes and/or proteinuria, and < 140/90 mmHg in other patients. RESULTS: The achievement rate of target systolic blood pressure was lower in the diabetic and hypertensive nephropathy groups than in the primary renal disease group (33.3%, 46.0% vs. 68.1%, p < 0.001). However, the number of antihypertensive medications increased in the diabetic and hypertensive nephropathy groups compared to the primary renal disease group (2.16, 2.04 vs. 1.55, p < 0.001). Inadequate blood pressure control was independently related to the underlying renal disease, with a significant difference between diabetic nephropathy and primary renal disease (odds ratio 3.19; 95% confidence interval, 2.16-4.69; p < 0.001). CONCLUSION: This study showed that blood pressure control differs by the underlying renal disease. Blood pressure control was poor especially in diabetic nephropathy despite multidrug combination antihypertensive treatment. It is necessary to verify whether strict blood pressure control improves patients' prognosis in diabetic nephropathy.

Impact of Focal Muscle Vibration on Flaccid Upper Limb Motor Paralysis following Acute Brain Disease: A Case Study.

Focal muscle vibration (FMV) is increasingly being recognized as a rehabilitative therapy for enhancing motor function in central nervous system (CNS) diseases, particularly in patients with fine motor control deficits stemming from CNS damage. Brain lesions from these diseases disrupt the motor networks, necessitating novel rehabilitation strategies. By applying vibrations to muscles, FMV stimulates sensory fibers to induce cortical activity and kinesthetic illusions. While initial studies have highlighted FMV's role in reducing spasticity, recent evidence points to its potential in treating motor paralysis. However, prior research has been limited by the lack of acute-phase studies and a focus on patients with minimal muscle contraction capability. This report aimed to explore FMV's efficacy on upper limb motor function in patients with flaccid motor paralysis immediately after acute CNS diseases. We report the case of a septuagenarian male with a brain abscess in the right parietal lobe, leading to flaccid motor paralysis. Rehabilitation included 28 sessions of occupational and physical therapy that incorporated FMV. Significant improvements were observed in upper extremity function, with moderate to very large effect sizes, while lower limb function showed lesser improvement without adverse effects. This case suggests the utility of FMV in enhancing upper-limb motor function after acute CNS injuries, potentially serving as a supplementary therapy for spontaneous recovery. This report contributes to emerging evidence on FMV's benefits in acute flaccid motor paralysis, expanding the documented therapeutic scope.

Geriatric Nutritional Risk Index is associated with adverse outcomes in patients with hypertension: the Fukushima Cohort study.

Malnutrition is reportedly associated with adverse clinical outcomes in various populations. However, associations between nutritional status and adverse outcomes in patients with hypertension have not been sufficiently elucidated. We therefore aimed to investigate the impact of nutritional status as evaluated by the Geriatric Nutritional Risk Index (GNRI) on adverse outcomes in patients with hypertension. We conducted a retrospective cohort study of 1588 hypertensive patients enrolled in the Fukushima Cohort Study. Participants were categorized into tertiles (T1-T3) according to GNRI at baseline. The primary endpoint of the present study was a kidney event, defined as a combination of a 50% decline in eGFR from baseline and end-stage kidney disease requiring kidney replacement therapy. Associations between GNRI and kidney events were assessed using Kaplan-Meier curves and multivariate Cox regression analyses. Median age was 64 years, 55% were men, median eGFR was 63.1 mL/min/1.73 m2, and median GNRI was 101.3. The lower GNRI group (T1) showed an increased incidence of kidney events in the Kaplan-Meier curve analysis. Compared to the highest GNRI group (T3), lower GNRI carried a higher risk of kidney events for both T2 (hazard ratio [HR] 1.38, 95% confidence interval [CI] 0.71-2.68) and T1 (HR 3.59, 95%CI 1.96-6.63). Similar relationships were observed for risks of all-cause death and cardiovascular events. Lower GNRI was associated with kidney events, all-cause death, and cardiovascular events in patients with hypertension. Nutritional status as evaluated by GNRI could offer a simple and useful predictor of adverse outcomes in this population.

Predicting CKD progression using time-series clustering and light gradient boosting machines.

Predicting the transition of kidney function in chronic kidney disease is difficult as specific symptoms are lacking and often overlooked, and progress occurs due to complicating factors. In this study, we applied time-series cluster analysis and a light gradient boosting machine to predict the trajectories of kidney function in non-dialysis dependent chronic kidney disease patients with baseline estimated glomerular filtration rate (GFR) ≥ 45 mL/min/1.73 m2. Based on 5-year changes in estimated GFR, participants were stratified into groups with similar trajectories by cluster analysis. Next, we applied the light gradient boosting machine algorithm and Shapley addictive explanation to develop a prediction model for clusters and identify important parameters for prediction. Data from 780 participants were available for analysis. Participants were classified into five classes (Class 1: n = 78, mean [± standard deviation] estimated GFR 100 ± 19.3 mL/min/1.73 m2; Class 2: n = 176, 76.0 ± 9.3 mL/min/1.73 m2; Class 3: n = 191, 59.8 ± 5.9 mL/min/1.73 m2; Class 4: n = 261, 52.7 ± 4.6 mL/min/1.73 m2; and Class 5: n = 74, 53.5 ± 12.0 mL/min/1.73 m2). Declines in estimated GFR were 8.9% in Class 1, 12.2% in Class 2, 4.9% in Class 3, 12.0% in Class 4, and 45.1% in Class 5 during the 5-year period. The accuracy of prediction was 0.675, and the top three most important Shapley addictive explanation values were 1.61 for baseline estimated GFR, 0.12 for hemoglobin, and 0.11 for body mass index. The estimated GFR transition of patients with preserved chronic kidney disease mostly depended on baseline estimated GFR, and the borderline for estimated GFR trajectory was nearly 50 mL/min/1.73 m2.

Impact of red blood cell distribution width-albumin ratio on prognosis of patients with CKD.

The red blood cell distribution width-albumin ratio (RAR) is a prognostic factor for adverse outcomes in various populations. However, whether RAR is associated with renal outcomes remains unclear. Therefore, we aimed to investigate the impact of RAR on the prognosis in patients with chronic kidney disease (CKD). We conducted a retrospective cohort study using 997 CKD patients who were enrolled in the Fukushima Cohort Study. Patients were categorized into tertiles (T1-3) according to the baseline RAR. The associations of RAR with end-stage kidney disease (ESKD) were assessed using Kaplan-Meier curves and multivariable cox regression analyses. Receiver operating characteristic (ROC) curves were performed to test whether significant differences were present between red cell distribution width (RDW) and RAR. The median age was 66, 57% were men, the median eGFR was 47.8 ml/min/1.73 m2, and the median value of RAR was 3.5. The higher RAR group showed an increased risk for ESKD in the Kaplan-Meier curve analysis. Compared to the lowest RAR group, higher RAR groups had a higher risk of ESKD (hazard ratio [HR] 1.37, 95% CI 0.68-2.78 and 2.92, 95% CI 1.44-5.94) for T2 and T3 groups, respectively. ROC curve analysis proved that the discriminating ability of RAR for ESKD was superior to RDW. A higher RAR value was associated with worse renal outcomes in patients with CKD. RAR could be a convenient and useful prognostic marker for renal prognosis.

Right Unilateral Spatial Neglect Improves with Intrinsic Motivation.

Background. In the acute phase of stroke, it is well known that the incidence and severity of unilateral spatial neglect (USN) are more significant in the right hemisphere injuries. Still, the detection of USN in left hemisphere injuries has been increasing in recent years. This trend is because behavioral assessments have prevented the exclusion of patients who are difficult to assess for USN or apathy using conventional paper-and-pencil tests (e.g., aphasia). Right USN and post-stroke apathy share many common lesions. Therefore, clinical symptoms may overlap, but little validation considers this. Case Study. A man (62 years old) determined to have the right USN and apathy was treated for six weeks in 3 terms. In the first term (weeks 1 to 2), the patient was treated for the right USN by conventional therapy. In the second term (3-4 weeks), treatment for right USN and apathy by goal-directed therapy based on affinity behavior was implemented. In the third term (5-6 weeks), goal-directed therapy based on affinity behavior was discontinued, and treatment was returned to conventional therapy only. In the second term (goal-directed therapy based on affinity behavior), the improvement in patients' apathy (clinical assessment for spontaneity) was more significant than the effect size in the third term (conventional therapy). There were no significant differences in USN (catherine bergego scale) and intrinsic motivation (pittsburgh rehabilitation participation scale). However, the effect size in the second term tended to be larger than in the third term (conventional therapy). Clinical Rehabilitation Impact. This report aims to demonstrate the limitations of current treatment for cases determined to have both right USN and apathy. Second, to assess the extent to which this new intervention can complement the limitations of current treatment.

Association between Serum Inorganic Phosphorus Levels and Adverse Outcomes in Chronic Kidney Disease: The Fukushima CKD Cohort Study.

Objective Although an association between serum inorganic phosphorus levels and a poor prognosis has been noted in dialysis patients, these associations have been insufficiently reported in non-dialysis-dependent chronic kidney disease (NDD-CKD) patients. This study attempted to determine the association between serum inorganic phosphorus levels and adverse outcomes in Japanese NDD-CKD patients. Methods We investigated the relationships between serum inorganic phosphorus levels and adverse outcomes, such as kidney events, cardiovascular events, and all-cause death, in Japanese NDD-CKD patients using longitudinal data from the Fukushima CKD Cohort Study with a median follow-up period of 2.8 years. The study evaluated 822 patients with NDD-CKD enrolled between June 2012 and July 2014. A kidney event was defined as a combination of doubling of the baseline serum creatinine or end-stage renal disease. Cox regression was performed to analyze the relationships of the quartile of the serum inorganic phosphorus with kidney events, cardiovascular events, and all-cause death. Results The frequency of kidney events per 1,000 person-years exhibited a U-shaped distribution based on serum inorganic phosphorus levels, with these levels not significantly associated with an increased risk of cardiovascular events and all-cause death. A multivariable Cox regression analysis showed an increased risk of kidney events for the highest quartile of the serum inorganic phosphorus levels (≥3.7 mg/dL) versus the second quartile (2.9-3.2 mg/dL, hazard ratio, 3.30; 95% confidence interval, 1.50-7.28; p=0.003). There were no significant associations between the serum calcium levels and adverse outcomes. Conclusion Serum inorganic phosphorus levels were associated with an increased risk of CKD progression in Japanese NDD-CKD patients.

Xanthine oxidase inhibitors are associated with reduced risk of cardiovascular disease.

As previous studies have reported finding an association between hyperuricemia and the development of cardiovascular and chronic kidney disease, hyperuricemia is thought to be an independent risk factor for hypertension and diabetic mellitus. However, we have not been able to determine whether the use of xanthine oxidase inhibitors can reduce cardiovascular disease. The present study used the longitudinal data of the Fukushima Cohort Study to investigate the relationship between the use of xanthine oxidase inhibitors and cardiovascular events in patients with cardiovascular risks. During the 3-year period between 2012 and 2014, a total of 2724 subjects were enrolled in the study and followed. A total of 2501 subjects had hypertension, diabetic mellitus, dyslipidemia, or chronic kidney disease, and were identified as having cardiovascular risks. The effects of xanthine oxidase inhibitor use on the development of cardiovascular events was evaluated in these patients using a time to event analysis. During the observational periods (median 2.7 years), the incidence of cardiovascular events was 20.7 in subjects with xanthine oxidase inhibitor and 11.2 (/1000 person-years, respectively) in those without. Although a univariate Cox regression analysis showed that the risk of cardiovascular events was significantly higher in subjects administered xanthine oxidase inhibitors (HR = 1.87, 95% CI 1.19-2.94, p = 0.007), the risk was significantly lower in subjects administered a xanthine oxidase inhibitor after adjustment for covariates (HR = 0.48, 95% CI 0.26-0.91; p = 0.024) compared to those without. Xanthine oxidase inhibitor use was associated with reduced risk of cardiovascular disease in patients with cardiovascular risk factors.

Association of Polypharmacy with Kidney Disease Progression in Adults with CKD.

BACKGROUND AND OBJECTIVE: Polypharmacy is common in patients with CKD and reportedly associated with adverse outcomes. However, its effect on kidney outcomes among patients with CKD has not been adequately elucidated. Hence, this investigation was aimed at exploring the association between polypharmacy and kidney failure requiring KRT. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: We retrospectively examined 1117 participants (median age, 66 years; 56% male; median eGFR, 48 ml/min per 1.73 m2) enrolled in the Fukushima CKD Cohort Study to investigate the association between the number of prescribed medications and adverse outcomes such as kidney failure, all-cause mortality, and cardiovascular events in Japanese patients with nondialysis-dependent CKD. Polypharmacy and hyperpolypharmacy were defined as the regular use of 5-9 and ≥10 medications per day, respectively. RESULTS: The median number of medications was eight; the prevalence of polypharmacy and hyperpolypharmacy was each 38%. During the observation period (median, 4.8 years), 120 developed kidney failure, 153 developed cardiovascular events, and 109 died. Compared with the use of fewer than five medications, adjusted hazard ratios (95% confidence intervals) associated with polypharmacy and hyperpolypharmacy were 2.28 (1.00 to 5.21) and 2.83 (1.21 to 6.66) for kidney failure, 1.60 (0.85 to 3.04) and 3.02 (1.59 to 5.74) for cardiovascular events, and 1.25 (0.62 to 2.53) and 2.80 (1.41 to 5.54) for all-cause mortality. CONCLUSIONS: The use of a high number of medications was associated with a high risk of kidney failure, cardiovascular events, and all-cause mortality in Japanese patients with nondialysis-dependent CKD under nephrology care.

Characterization and comparison of groundwater quality and redox conditions in the Arakawa Lowland and Musashino Upland, southern Kanto Plain of the Tokyo Metropolitan area, Japan.

Groundwater is essential for the Earth biosphere but is often contaminated by harmful chemical compounds due to both anthropogenic and natural causes. A key factor controlling the fate of harmful chemicals in groundwater is the reduction/oxidation (redox) conditions. The formation factors for the groundwater redox conditions are insufficiently understood. In this study, long-term groundwater quality beneath one of the world megacities was monitored and evaluated. We measured and compared hydrogeochemical conditions including groundwater quality (35 chemical parameters) and redox conditions of five aquifers in the Arakawa Lowland and Musashino Upland, southern Kanto Plain of the Tokyo Metropolitan area, Japan. Monitoring results suggested the following: The main origin of groundwater is precipitation in both the Lowland and Upland areas. The three aquifers in the Arakawa Lowland are likely fully separated, with one unconfined and two confined aquifers under iron reducing and methanogenic conditions, respectively. Oppositely, in the Musashino Upland, the water masses in the two aquifers are likely partly connected, under aerobic conditions, and undergoing the same groundwater recharge and flow processes under similar hydrogeological conditions. The different groundwater redox conditions observed are likely caused by the very different groundwater residence times for the Arakawa Lowland and Musashino Upland.

Pathological findings of progressive renal involvement in a patient with TAFRO syndrome.

TAFRO syndrome (thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly) is thought of as an atypical type of idiopathic multicentric Castleman's disease. Interleukin-6, vascular endothelial growth factor (VEGF), and other cytokines are considered etiological factors. A 45-year-old woman was admitted to hospital with unknown fever and abdominal pain. She had thrombocytopenia, anasarca, proteinuria/hematuria, and slight hepatosplenomegaly. Based on her clinical course and laboratory data, she was diagnosed as having TAFRO syndrome. Kidney biopsy showed a membranoproliferative glomerulonephritis (MPGN)-like lesion containing lobulations of glomeruli, endothelial cell swelling, double contours of the glomerular basement membrane, and mesangiolysis. She was treated with methylprednisolone pulse (500 mg/day) and oral prednisolone (60 mg/day) therapy. The pleural effusion and ascites disappeared, and renal function normalized. Cyclosporine was added to prevent relapse. She went home, with no relapse 8 months after hospitalization. MPGN-like lesions were found frequently in patients with TAFRO syndrome in recent reports. However, there are few reports of pathologically confirmed cases of progressive renal involvement in TAFRO syndrome. The relationship between VEGF expression in renal tissue and the pathogenesis of renal injury in TAFRO syndrome was investigated in the present case.

Tracking Infiltration Front Depth Using Time-lapse Multi-offset Gathers Collected with Array Antenna Ground Penetrating Radar.

A Ground Penetrating Radar (GPR) system based on a ground-coupled, densely populated antenna array was used to collect data during an infiltration experiment conducted at a test site near the Tottori Sand Dune, Japan. The antenna array used in this study consists of 10 transmitting antennas (Tx) and 11 receiving antennas (Rx). For this experiment, the system was configured to use all possible Tx-Rx pairings, resulting in a Multi-Offset Gather (MOG) consisting of 110 Tx-Rx combinations. The array was left stationary at a position directly above the infiltration area and data were collected every 1.5 seconds using a time-based trigger. Common-Offset Gather (COG) and Common Mid-Point (CMP) data cubes were reconstructed from the MOG data during post-processing. There have been few studies that used time-lapse CMP data to estimate changes in velocity of propagation. In this study, electromagnetic (EM) wave velocity was estimated heuristically at 1-minute intervals from the reconstructed CMP data through curve fitting, using the hyperbola equation. We then proceeded to calculate the depth of the wetting front. The evolution of the wetting front over time obtain through this method is consistent with the observations from a soil moisture sensor which was placed at a depth below 20 cm. The results obtained in this study demonstrate the ability of such array GPR system to monitor a subsurface dynamic process like water infiltration accurately and quantitatively.

Immunoglobulin gamma3-heavy-chain deposition disease: report of a case and relationship with hypocomplementemia.

The authors describe a 54-year-old woman presenting with proteinuria, hematuria, and hypocomplementemia whose renal biopsy results showed diffuse increase in mesangial matrix and nodular formations in several glomeruli with the deposition of immunoglobulin gamma3-heavy-chain and complement components C1q and C3 in the glomeruli and on the tubular basement membranes, without associated light-chain deposits. Staining for the constant domains of gamma-heavy-chain showed a deletion of the first constant domain (CH1). These findings were consistent with those of gamma-heavy-chain deposition disease (gamma-HCDD). The patient was treated monthly with melphalan and prednisolone although a bone marrow aspirate did not show findings suggestive of plasmacytoma. Six courses of melphalan and prednisolone therapy resulted in a marked reduction of urinary protein excretion and marked rise of complement levels. The current case is the fourth HCDD patient reported featuring gamma3-heavy-chain deposition who showed severe hypocomplementemia and responded to chemotherapy with improved renal parameters and complement levels. A review of previously reported cases of HCDD showed that some but not all HCDD cases were associated with hypocomplementemia. The authors also discuss here the relationship of HCDD to hypocomplementemia.

Delineating high-density areas in spatial Poisson fields from strip-transect sampling using indicator geostatistics: application to unexploded ordnance removal.

An approach for delineating high anomaly density areas within a mixture of two or more spatial Poisson fields based on limited sample data collected along strip transects was developed. All sampled anomalies were transformed to anomaly count data and indicator kriging was used to estimate the probability of exceeding a threshold value derived from the cdf of the background homogeneous Poisson field. The threshold value was determined so that the delineation of high-density areas was optimized. Additionally, a low-pass filter was applied to the transect data to enhance such segmentation. Example calculations were completed using a controlled military model site, in which accurate delineation of clusters of unexploded ordnance (UXO) was required for site cleanup.

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.