Removing co-occurring contaminants of arsenic and vanadium with full-scale arsenic adsorptive media systems.

The U.S. Environmental Protection Agency conducted an Arsenic Demonstration Program (ADP) whereby 50 full, small-scale arsenic removal treatment systems were evaluated for removing arsenic to below the maximum contaminant level of 10 µg/L and their operating cost for a minimum of 1 year. The majority (28) of the systems installed were adsorptive media (AM) technology with the media replaced when exhausted. This paper reports on the results of two ADP projects and two laboratory rapid small-scale column tests (RSSCTs) using the iron-based media, Bayoxide E33 (E33) AM for the removal of arsenic (As) and the co-occurring contaminants (COCs) of vanadium and to a lesser degree fluoride (F) and nitrate (NO3). The ADP studies found that the AM effectively removed the COC of V, but with a lower removal capacity than of As. One ADP study found the AM to be ineffective for the removal of F and NO3. The RSSCT conducted on two other source waters also found vanadium to be removed by the same AM. The study results suggested the AM selectively sequence of As > V > F = N. The study also investigated the AM to achieve an As limit of 5 µg/L. The AM was found to reduce As to below 5 µg/L with around 30% shorter treatment run lengths.

Removing arsenic and co-occurring contaminants from drinking water by full-scale ion exchange and point-of-use/point-of-entry reverse osmosis systems.

This study investigated the performance of two full-scale ion exchange (IX) systems, one point-of-entry (POE) reverse osmosis (RO) system and nine point-of-use (POU) RO units for simultaneous removal of arsenic and several co-occurring contaminants from drinking water. The study was performed as part of the U.S. Environmental Protection Agency's Arsenic Treatment Demonstration Program. The IX systems, with strong base anionic (SBA) resins, effectively removed arsenic (As), nitrate (NO3-) and uranium (U) to below respective maximum contaminant levels and vanadium (V) and molybdenum (Mo) to below 2 µg/L. The useful run length, as determined by either 10-mg/L (as N) nitrate or 10-µg/L arsenic breakthrough, was approximately 400 bed volumes (BV) initially. However, it was decreased over time, e.g., by 15% in 13 months at one site and 33% in 7 months at another site, apparently caused by resin fouling due to the presence of 2-mg/L natural organic matter (NOM) in source waters. The use of dual resins ‒ an acrylic SBA resin underlain by a polystyrene SBA resin ‒ effectively removed NOM and allowed the system to perform at its baseline level through the 13-month study. Arsenic and nitrate peaking occurred when the resins were not regenerated timely. The removal of contaminants appeared to follow a selectivity sequence: U, Mo > V > SO42- > HAsO42- > NO3- > HCO3-. RO effectively removed arsenic, nitrate, antimony, uranium and vanadium, mostly with a >99% rejection rate. The POE RO coupled with dual plumbing (only treating a fraction of water for potable use) and POU RO in individual homes could be used as low-cost alternatives to traditional RO treatment.

Patterns of Arsenic Release in Drinking Water Distribution Systems.

Retrospective analysis of 20 water systems from the USEPA's Arsenic Demonstration Program revealed three patterns of arsenic levels at the tap, after arsenic treatment of the source well water. Following an initial destabilization period, Pattern A systems (6/20 with low iron/manganese in source water and plastic piping) had arsenic concentrations that did not change as water traveled to consumer taps (conservative contaminant behavior). Pattern B systems (8/20 with high iron/manganese in source water and iron piping) had consistently higher arsenic concentrations at consumer taps, above the arsenic content of incoming treated water, for months to more than a year after arsenic treatment (non-conservative behavior). Pattern C systems (6/20 with additional occasional arsenic treatment complications) experienced multiple arsenic spikes at consumer taps (non-conservative and unpredictable behavior). These field observations suggest that in some water distribution systems arsenic may linger long after it has been removed at its source.

Arsenic/Iron Removal From Groundwater With Elevated Ammonia and Natural Organic Matter.

Under the US Environmental Protection Agency's Arsenic Demonstration Program, an iron (Fe) removal process consisting of permanganate oxidation and greensand filtration was shown to be effective in removing soluble arsenic (As(III)) (24.1 µg/L on average) from Waynesville, Ill., groundwater, which also contained elevated ammonia (3.8 mg/L [as N] on average) and natural organic matter (NOM) (7.9 mg/L, on average, of total organic carbon). Chlorine was not used because it forms chloramines, which are not effective in oxidizing As(III). A permanganate dose over the stoichiometric amount was applied to overcome interference from NOM-based on jar testing conducted for this and another Fe removal system at Sauk Centre, Minn. These pressure filtration syste ms had no air contact, thus allowing simultaneous oxidation of As(III) and ferrous iron. Compliance monitoring data to date show consistently low arsenic (<4 µg/L) and Fe (<0.05 mg/L) since the commencement of system operation in July 2009.

Regenerating an Arsenic Removal Iron-Bed Adsorptive Media System, Part 1: The Regeneration Process.

Adsorptive media technology is frequently used by small water systems to remove arsenic because of its simplicity and efficiency. Current practice is to replace the media when it no longer reduces arsenic below the maximum contaminant level of 10 µg/L that the US Environmental Protection Agency has set for drinking water. Media replacement typically accounts for approximately 80% of the total operational and maintenance costs. One potential option to reduce the cost is onsite regeneration and reuse of the media. To evaluate the regeneration option, three consecutive regeneration studies were conducted on a full-scale adsorptive media system. This article, the first of a two- part series, describes the regeneration process and its efficacy in stripping arsenic and other contaminants from exhausted media. Study results found that a three- step regeneration process of media backwash, caustic regeneration, and acid neutralization conditioning proved effective for stripping arsenic and other contaminants from the exhausted media.

Regenerating an Arsenic Removal Iron-Bed Adsorptive Media System, Part 2: Performance and Cost.

Replacement of exhausted, adsorptive media used to remove arsenic from drinking water accounts for approximately 80% of total operational and maintenance costs of this commonly used small system technology. Results of three full-scale system studies of an onsite media regeneration process (discussed in the first article of this two-part series) showed it to be effective in stripping arsenic and other contaminants from a granular ferric oxide (GFO) exhausted adsorptive media. This second article details the performance of the regenerated media to remove arsenic through multiple regeneration cycles and the approximate cost savings of regeneration over media replacement. Results indicated that media regeneration did not appear to have a major detrimental effect on the performance of the GFO media, and the regeneration cost was potentially less than the media replacement cost. Therefore, onsite regeneration offers small systems a possible alternative to media replacement when removing arsenic from drinking water using iron-based adsorptive media technology.

Regeneration of iron-based adsorptive media used for removing arsenic from groundwater.

Adsorptive media technology is regarded as a simple, low cost method of removing arsenic from drinking water particularly for small systems. Currently, when the effluent of a treatment system reaches the USEPA maximum contaminant level (MCL) of 10 ug/L, the exhausted media is removed and replaced by new virgin media. Although the commonly used iron-based media products are reasonable in price, the replacement cost accounts for around 80% of the systems total operational costs. One option to media replacement is on-site regeneration and reuse of the exhausted media. To determine whether an iron based media can be successfully regenerated and reused, laboratory batch and column regeneration tests were conducted on six exhausted iron-based media products obtained from six full scale arsenic removal treatment systems. Batch tests conducted on three of the media products to evaluate the effectiveness of 1-6% caustic regenerant solutions found that arsenic desorption increased until around 4%. Using 4% caustic solutions, the columns tests on the six exhausted media products showed arsenic removals ranged from 25 to 90% with the best results obtained with the Severn Trent E33 media. Exposing the media to caustic (pH ≥ 13) and acid (pH ≤ 2) solutions found minimal media loss with the caustic solution, but significant media dissolution with a pH 2 acid solution. A six column pilot plant test at an Ohio test site with the lab regenerated media products found that the regenerated media could achieve arsenic removals somewhat similar to virgin media.

Arsenic species in drinking water wells in the USA with high arsenic concentrations.

Arsenic exists in ground water as oxyanions having two oxidation states, As(III) and As(V), and its concentrations vary widely and regionally across the United States (USA). Because of the difference in toxicity and removability of As(III) and As(V), arsenic speciation is important in the selection and design of an arsenic treatment systems. Identifying the arsenic species is also helpful in explaining and understanding the behavior and characteristics of arsenic in the environment. Although laboratory methods exist for speciating arsenic in water samples, the lack of a universal preservation method has led to the predominant use of field separation methods that are somewhat complex and costly. Thus, very few studies have incorporated arsenic speciation. A U.S. Environmental protection Agency (EPA) arsenic treatment research program provided a unique opportunity to speciate the naturally occurring arsenic in 65 well waters scattered across the USA with many of them being speciated monthly for up to three years. Speciation test data showed that 31 wells had predominantly As(V), 29 had predominantly As(III) and five had a mixture of both. A general pattern was found where As(III) was the dominant species in midwest ground waters where anoxic conditions and elevated iron concentrations prevailed and the well waters in the east, west and farwest had either As(III) or As(V) as the dominant species. The monthly (12-36) speciation tests results at many of these sites also found no major changes in arsenic species over time.

Acute pathological laughter.

Pseudobulbar affect is a condition characterized by uncontrollable episodes of inappropriate laughing or crying that are disproportionate and discordant to the situation at hand. We report on a 16-year-old woman presenting with acute pathological laughter in the context of CNS demyelinating disease. Brain MRI scans fortuitously obtained before and after the onset of this symptom demonstrated acute gadolinium-enhancing lesions in the cerebral peduncles. The etiology of this condition remains theoretical; however, the results here provide further insights into the pathways of emotional control.

The clinical spectrum of duodenal polyps in pediatrics.

OBJECTIVES: The aim of this retrospective study was to determine the prevalence, clinical presentation, and histologic subclassification of duodenal polyps identified on endoscopy (EGD) in pediatric patients. METHODS: We performed an 18-year retrospective study of all pediatric patients (< 21 years) with duodenal polyps diagnosed between 1983 and 2001 at The Johns Hopkins Children's Center. Our analysis includes a formal histologic evaluation of duodenal polyps either biopsied using cold-forceps or removed by snare cautery. RESULTS: Duodenal polyps were reported in 22 of 5766 EGDs (0.4%) performed in 16 (M:F; 1:1) patients with a mean (SD) age of 14.1 (5.1) years. Polyps were equal in both the Caucasian and African American population (adjusted ratio 1.2:1). The histologic subtypes included Adenomatous (42%), Brunner's gland hyperplastic (33%), hamartomatous (17%), and heterotopic gastric gland polyps (8%). The most frequent indication for EGD was surveillance in patients with polyposis syndromes; most of these patients were asymptomatic at the time of their EGD. In comparison, the most frequent indication for an EGD in patients without polyposis syndromes was abdominal pain and vomiting. CONCLUSIONS: Duodenal polyps are most frequently encountered in children with polyposis syndromes, most of whom are asymptomatic. In nonsyndromic patients, the most common histologic subtype is Brunner's gland hyperplastic polyp and presenting symptoms include abdominal pain and vomiting.

Endoscopic findings predict the histologic diagnosis in gastrointestinal graft-versus-host disease.

BACKGROUND AND STUDY AIMS: Graft-versus-host disease (GvHD) of the gastrointestinal tract is a major cause of morbidity and mortality after allogeneic bone marrow transplantation (BMT). Whether endoscopic findings predict the histologic diagnosis of GvHD in the gastrointestinal tract remains controversial. We performed a study to determine the diagnostic accuracy of macroscopic endoscopy findings in the diagnosis of acute and chronic histologically proven gastrointestinal GvHD (GI-GvHD). PATIENTS AND METHODS: Endoscopic images from the intestinal mucosa of post-BMT patients were blindly graded as positive or negative for GI-GvHD and compared with corresponding histological findings, which were used as the gold standard. RESULTS: 44 BMT patients were referred for 96 endoscopic evaluations. Using 162 endoscopy-biopsy pairs, a positive association between endoscopic grading and histologic grading of GI-GvHD (odds ratio [OR] = 11.97, 95% CI 3.86, 37.16) was observed. Endoscopic diagnosis correctly predicted histologic diagnosis in both acute and chronic GI-GvHD (OR = 9.3 vs. 23.1, P = 0.31). CONCLUSIONS: The diagnostic accuracy of endoscopy was high in both acute and chronic histologically proven GI-GvHD. Accurate diagnosis of GI-GvHD might be obtained with mucosal biopsies from either the upper or lower gastrointestinal tract. Endoscopy may play a significant role in establishing early diagnosis and treatment for GI-GvHD in patients following BMT, but histologic evaluation of the gastrointestinal mucosa is needed to confirm the final diagnosis.

Distinctive molecular genetic alterations in sporadic and familial adenomatous polyposis-associated pancreatoblastomas : frequent alterations in the APC/beta-catenin pathway and chromosome 11p.

Pancreatoblastomas are unusual malignant neoplasms of the pediatric pancreas that may also rarely affect adults. The molecular pathogenesis of pancreatoblastomas is unknown. They are clinicopathologically distinct from adult pancreatic ductal adenocarcinomas, but their occasional occurrence in patients with Beckwith-Wiedemann syndrome and the case presented here of a pancreatoblastoma in an adult patient with familial adenomatous polyposis (FAP) suggests that they might bear a genetic similarity to other infantile embryonal tumors such as hepatoblastomas. We analyzed a series of nine pancreatoblastomas for mutations common to other embryonal malignancies including somatic alterations in the adenomatous polyposis coli (APC)/beta-catenin pathway and chromosome 11p, using immunohistochemistry for beta-catenin, 5q and 11p allelic loss assays, and direct DNA sequencing of exon 3 of the beta-catenin gene and the mutation cluster region of the APC gene. In addition, we analyzed the pancreatoblastomas for alterations found in adult-type pancreatic ductal adenocarcinomas including mutations in the K-ras oncogene and the p53 and DPC4 tumor suppressor genes, using direct DNA sequencing of exon 1 of K-ras and immunohistochemistry for p53 and Dpc4. Allelic loss on chromosome 11p was the most common genetic alteration in pancreatoblastomas, present in 86% (six of seven informative cases). Molecular alterations in the APC/beta-catenin pathway were detected in 67% (six of nine), including five neoplasms with activating mutations of the beta-catenin oncogene and the one FAP-associated tumor with biallelic APC inactivation (germline truncating mutation combined with loss of the wild-type allele); seven neoplasms showed abnormal nuclear accumulation of beta-catenin protein. In contrast, loss of Dpc4 protein expression was present in only two cases (one diffuse and one focal), and no alterations in the K-ras gene or p53 expression were detected. Our findings indicate that pancreatoblastomas are genetically distinct from the more common pancreatic ductal adenocarcinomas, but bear a close molecular pathogenesis to hepatoblastomas. In addition, pancreatoblastoma may represent an extracolonic manifestation of FAP.

Hyperplastic polyps of the esophagus and esophagogastric junction: histologic and clinicopathologic findings.

Hyperplastic polyps of the esophagus and esophagogastric junction region (EGJ) are uncommon lesions characterized by hyperplastic epithelium (foveolar-type, squamous, or both) with variable amounts of inflamed stroma. They have been reported almost exclusively in the radiologic and clinical literature as occurring predominantly in association with gastroesophageal reflux disease (GERD). Comprehensive histologic and clinicopathologic evaluation of these polyps, their association with background mucosal pathology, and their association with Barrett's esophagus has not been previously performed. We studied 30 hyperplastic polyps from 27 patients and characterized the histologic, endoscopic, and clinical features of both the polyps and the background esophagus. Hyperplastic polyps were most common in the region of the EGJ (67%), followed by the distal esophagus (30%) and mid-esophagus (3%). Most (80%) were composed of predominantly cardiac-type mucosa, predominantly squamous mucosa (17%), or an admixture (3%). Intestinal metaplasia of the polyp was present in only 7% and low-grade dysplasia in only 3%. In the majority of cases (67%) hyperplastic polyps were associated with concurrent or recent ulcers or erosive esophagitis. In most cases (48%) esophageal injury was associated with GERD, but other potential etiologies included medications, infection, anastomotic or polypectomy sites, vomiting, and photodynamic therapy. Four patients (15%) had Barrett's esophagus, three of whom had or developed dysplastic Barrett's mucosa. These results underscore the pathogenesis of esophageal/EGJ region hyperplastic polyps as a mucosal regenerative response to surrounding mucosal injury. Careful clinical history and biopsy of the nonpolypoid mucosa are essential for determining the clinicopathologic context in which the polyps have developed.

Superficial fibromatoses are genetically distinct from deep fibromatoses.

Whereas deep fibromatoses (abdominal, extra-abdominal, mesenteric) display locally aggressive behavior, superficial fibromatoses typically remain small and less likely to recur despite essentially identical morphology. Somatic beta-catenin or APC gene mutations have been reported in < or =74% of sporadic deep fibromatoses and in virtually 100% of Gardner syndrome-associated fibromatoses, whereas genetic events in superficial fibromatoses remain less well characterized. We performed immunohistochemical staining for beta-catenin on 29 superficial fibromatoses (22 palmar, 5 plantar, 1 penile, and 1 infantile digital fibromatosis) and 5 deep fibromatoses. Mutations of beta-catenin and APC genes were analyzed in cases of superficial fibromatoses by direct DNA sequencing of the beta-catenin gene on Exon 3 encompassing the GSK-3 36 phosphorylation region and of the APC gene on the mutation cluster region. Nuclear accumulation of beta-catenin was present in 86% (25/29) of superficial fibromatosis cases ranging from 5 to 100% of nuclei (mean, 13%; median, 10%), though in a minority of nuclei in most examples. Deep fibromatoses had 60 to 100% nuclear staining in all five cases. No somatic mutations of beta-catenin or APC genes were identified in any of the superficial fibromatoses. In contrast to deep fibromatoses, superficial fibromatoses lack beta-catenin and APC gene mutations; the significance of focal nuclear beta-catenin accumulation is unclear. This difference may account inpart for their divergent clinical manifestations despite their morphologic resemblance to deep fibromatoses.

Colchicine toxicity: distinct morphologic findings in gastrointestinal biopsies.

Colchicine is an alkaloid with antimitotic ability used to treat a variety of medical conditions. Colchicine toxicity can result in multiorgan failure and death. The histopathologic features of colchicine toxicity in gastrointestinal biopsies have not been reported. Twenty-one gastrointestinal mucosal biopsies obtained from nine patients receiving oral colchicine therapy were studied. Immunohistochemical staining for Ki67 proliferation antigen was performed, and medical records of each patient were reviewed. All patients had a history of gout. Four patients with chronic renal failure also had clinical evidence of colchicine toxicity, and the other five patients did not. Distinct morphologic changes, seen as metaphase mitoses, epithelial pseudostratification, and loss of polarity, were seen in biopsy material from 4 of 4 (100%) patients with clinical colchicine toxicity. Three of these four cases (75%) also contained abundant crypt apoptotic bodies. These morphologic features were best seen in the biopsies from duodenum and gastric antrum, with relative sparing of the gastric body in the upper gastrointestinal tract. Ki67 staining demonstrated an expansion of the proliferating region in three available cases with clinical colchicine toxicity. These distinctive morphologic features were not seen in the five patients without clinical colchicine toxicity. These results indicate that colchicine toxicity can produce diagnostic morphologic features in gastrointestinal mucosal biopsies. Recognition of these features is important because colchicine toxicity can be fatal if undiagnosed clinically.

Clinicopathologic and molecular analysis of high-grade dysplasia and early adenocarcinoma in short- versus long-segment Barrett esophagus.

Barrett esophagus, especially dysplastic Barrett mucosa, has been regarded as a preneoplastic lesion for esophageal adenocarcinoma. However, the etiology and pathogenesis of dysplasia and early adenocarcinoma in short- (SSBE) and long- (LSBE) segment Barrett esophagus have not been studied in detail. The aims of this study were to clarify clinicopathologic and genetic differences between high-grade dysplasia (HGD) and early adenocarcinoma in SSBE versus LSBE. We analyzed the clinicopathologic features from 47 patients (19 SSBE [<3 cm] and 28 LSBE [> or =3 cm]) with esophagectomy for HGD/T1 adenocarcinoma. Allelic losses on chromosomes 3p (FIHT), 5q (APC), 9p (p16), and 17p (p53) were compared in 12 HGD and 9 T1 tumors from 19 cases of SSBE and in 23 HGD and 15 T1 tumors from 28 cases of LSBE. Patients with SSBE were more likely to be smokers than were patients with LSBE (94.7% v 57.1%; P =.004). HGD or T1 tumors arising from SSBE were less likely to show adjoining nondysplastic Barrett mucosa than those from LSBE (73.6% v 100%; P =.02). LSBE more frequently showed a circumferential pattern of Barrett mucosa than did SSBE (96.4% v 47.3%; P =.0002). Chromosomal allelic losses on 3p, 5q, 9p, and 17p were detected in 19% (4 of 21), 43% (15 of 35), 40% (14 of 35), and 48% (16 of 33) of HGD, respectively, and 26% (5 of 19), 35% (8 of 23), 35% (8 of 23), and 57% (13 of 23) of T1 tumor, respectively. There were no significant differences in allelic loss of 3p, 5q, 9p, or 17p in HGD or T1 tumors from SSBE versus LSBE. These results suggest that both HGD and early adenocarcinoma in SSBE and LSBE may occur through similar genetic alterations, whereas there are some clinicopathologic differences between SSBE and LSBE. HUM PATHOL