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PubMed1997

[Severity of ingestion of caustic substance in children].

BACKGROUND: Caustic ingestion is frequent in children, sometimes leading to esophageal stricture. PATIENTS AND METHODS: Between 1988 and 1994, esogastroscopy was performed in 65 children after caustic ingestion. The children were classified in three groups: no lesion (group A), minimal lesions (group B) and severe lesions (group C). Nature of the caustic substance, clinical signs and evolution were compared in the three groups. RESULTS: Median age was 2 years for the 65 children (24 girls, 41 boys). Ingestion occurred at home (94%) during meal periods. Substances were dishwater detergents (n = 14), oven cleaner (n = 10), bleach (n = 9), washing powder (n = 4), others (n = 20), more often in a liquid form (n = 37) than solid (n = 28). Children had no symptoms (57%), presented emesis (n = 20) or abdominal pain (n = 10) not correlated to endoscopic findings, and hematemesis (n = 3) or respiratory distress (n = 4), both symptoms seen only in group C. Buccal lesions (41%) were not correlated to endoscopic findings. After endoscopy, 28 children (43%) were classified into group A and 20 children (31%) in group B. Among the 17 children (26%) of the group C, eight developed an esophageal stricture: seven long strictures requiring replacement of the esophagus, one short stricture requiring repeated dilations. CONCLUSION: Esophageal stricture is still a severe complication after caustic ingestion. These data stress the interest of controlled studies to confirm the preventive role of high dose corticosteroids, and the importance of the prevention of accidental caustic ingestions in children.

Accidents, Home↗
PubMed2002

Treatment of caustic ingestion: an analysis of 239 cases.

The objective of the present study was to analyze a 37-year historical series of patients who had ingested caustic substances, and who were treated in a teaching hospital, to assess the effectiveness of the therapy administered during this period. We studied 239 patients who ingested caustic soda (NaOH) from 1957 to 1994. Data were collected from the medical records of the patients and from interviews with them and analyzed by software and by statistical tests of association. The results showed that more women than men ingested caustic substances (57%, n=153). Ingestion was associated with suicidal intent in 60% of cases and was accidental in 37.2% of cases. The amount of substance ingested ranged from a trace to as much as three tablespoons, with the amount tending to be larger in the suicide attempts. Of the 215 patients for whom information about complications due to ingestion was available, 88.4% (190) presented lesions of the esophagus (73% with stenosis), 1% died during the acute phase, and 10.6% did not present complications. The data revealed that the presence and severity of stenosis were correlated with the amount of caustic substance ingested. The treatment received by the patients in the study sample varied over the years according to the prevailing literature recommendations. Based on our review, we conclude that neither the use of an antidote nor early treatment immediately after ingestion is effective. Treatment with a corticosteroid (1.5-2 mg/kg/day prednisone), an antibiotic, and a high-protein and hypercaloric diet seems to be beneficial for patients who ingest small or medium amounts of caustic soda. When 2-3 tablespoons are ingested, corticosteroids, in addition to being unable to prevent the formation of esophageal stenosis, increase the risk of other complications.

Brazil↗
PubMed2001

Is esophagogastroduodenoscopy necessary in all caustic ingestions?

BACKGROUND: It is unclear whether symptoms alone can identify patients with caustic ingestion who will benefit from esophagogastroduodenoscopy (EGD). The published data are contradictory. The purpose of the current study was to determine the relationship between initial symptoms and EGD findings in patients with caustic ingestion. METHODS: Chart review of all caustic ingestions who underwent EGD during a 4-year period (December 1993 through November 1997). RESULTS: Twenty-eight patients (15 girls; mean age, 2.7 years (range, 0.92-13.33) underwent EGD after caustic ingestion. Fourteen percent (4/28) of patients were asymptomatic, and findings on endoscopy were normal. Another 57% (16/28) had normal endoscopic findings, although all were symptomatic. Twenty-nine percent (8/28) of patients had esophageal injury on EGD, and all were symptomatic. Esophageal injury was graded as 1 (mucosal erythema), 2 (superficial burns; noncircumferential) or 3 (deep burns; circumferential). The injury was grade 1 in three of eight patients and grade 2 in two; all had one symptom each. Grade 3 injury was found in three of eight patients: two had two symptoms (drooling and vomiting, drooling and stridor), and one had one symptom (dysphagia). All patients with grade 3 injury subsequently underwent esophageal dilations. Follow-up information was secured for two of the three patients with grade 1 injury and both patients with grade 2 injury at 34.3 months (range, 24-50) after the ingestion, and all were asymptomatic. Of the 20 patients with absence of esophageal mucosal damage, follow-up data were available for 15 patients at 37.2 months (range, 7-63) after the event and all were well. CONCLUSIONS: All patients with clinically significant injury (grades 2 and 3) were symptomatic at initial assessment. No single symptom or combination of symptoms could identify all patients with esophageal injury. All asymptomatic patients had normal findings on endoscopic examinations. Esophagogastroduodenoscopy seems unnecessary in asymptomatic patients with alleged caustic ingestion. A larger, prospective study would be necessary to unequivocally answer this clinically important question.

Adolescent↗
PubMed2003

Hair relaxers: a benign caustic ingestion?

BACKGROUND: Despite federally legislated safety regulations, caustic ingestions remain a significant problem in the pediatric population. The current standard of care for caustic ingestion includes upper gastrointestinal endoscopy in most cases. Hair relaxers are a common caustic ingestion at our institution, yet few data have been published describing the clinical or endoscopic outcome. We explored the relative frequency of hair relaxer ingestion, the incidence of associated upper gastrointestinal injury, and the adverse clinical sequelae resulting from these ingestions. METHODS: Consecutive caustic ingestions admitted to our institution between January 1990 and January 2001 were identified. The data were collected through retrospective physician chart review, were analyzed, and were pooled with the existing literature to evaluate for the presence of esophageal injury. RESULTS: 96 charts were reviewed, 29 (30%) of which were hair relaxer ingestions that underwent esophagogastroduodenoscopy; these ingestions served as our study cohort. The median age of the cohort was 14.0 months and patients were evenly divided in gender. The most common symptoms at presentation were drooling and emesis. At endoscopy, lip and oropharyngeal mucosa were most commonly affected. While six patients (20.7%) had Grade I esophageal mucosal injury and five patients (17.2%) had Grade I gastric mucosal injury, none had greater than Grade I mucosal damage. No adverse clinical events were identified. When our data were combined with all previously published cohort data, the findings were similar and no adverse clinical outcomes were reported. CONCLUSIONS: Hair relaxer is the most common childhood caustic ingestion presenting to our large metropolitan tertiary care center. Symptoms are common at presentation. However, despite the high pH of these products, no clinically significant esophageal or gastric mucosal injuries and no long-term sequelae were identified.

Burns, Chemical↗
PubMedDate not supplied

Ingestion of caustic substances by adults.

Caustic products are responsible for the most serious cases of poisoning, which are always emergency cases. In this paper, we review demographic features and endoscopic results of the patients admitted to a university emergency department with a history of caustic substance ingestion between January 2000 and June 2003. Thirty-seven patients were included in this study. Twenty-one of the patients were female and 16 were male. The mean age of the patients was 30.9 +/- 14.7 years. The agents included sodium hypochlorite in 24 patients and hydrochloric acid in 13 patients. All the patients ingested these agents orally. The mean interval time of admission to emergency department after ingestion of caustic agent was 5.4 +/- 5.6 hours. Endoscopy was attempted in 37 patients. Endoscopic results were as follows: grade 0 in 8 (21.6%) patients, grade 1 in 17 (45.9%) patients, grade 2a in 5 (13.5%) patients, and grade 2b in 7 (18.9%) patients. We believe that early signs and symptoms after caustic substance ingestion are not consistent with the extent of damage, and endoscopy is the only reliable method to assess injury. It is important that efforts should be made to educate the public about the dangers of caustic substances so that their threat may be diminished.

Adolescent↗
PubMed2005

Respiratory and gastrointestinal complications of caustic ingestion in children.

OBJECTIVES: To determine circumstances surrounding the ingestion of caustic substances, the incidence of respiratory and gastrointestinal symptoms at presentation, and the degree of investigation and active treatment during hospitalisation. Long term respiratory and gastrointestinal sequelae were also studied. DESIGN: Retrospective case note study covering a 10 year period. SETTING: Tertiary children's hospital. PATIENTS: Children and adolescents presenting following caustic ingestions to the Royal Children's Hospital, Melbourne. MAIN OUTCOME MEASURES: Requirement for interventional oesophagoscopy/bronchoscopy, respiratory support or admission to intensive care, and long term gastrointestinal or respiratory sequelae noted. RESULTS: Thirty two cases of caustic ingestion were identified in 31 patients (median age 2.6 years; 78% boys). The average time in hospital was 2 days. Two patients (6%) required intensive care nursing, and both required intubation with mechanical ventilation (average 33 hours). Thirty patients (97%) underwent diagnostic oesophagoscopy, and two underwent laryngoscopy or bronchoscopy for visualisation of the upper airway. No patient had long term respiratory consequences. Two patients (6%) sustained significant oesophageal injuries requiring interventional oesophagoscopy. CONCLUSIONS: Caustic ingestion is overrepresented in boys. Most ingestions involve household cleaning products. Symptoms on admission do not usually require intensive care admission. Gastrointestinal symptoms predominate at presentation, however, these are usually mild. Respiratory symptoms are uncommon and respiratory involvement requiring intervention is rare, although the presence of respiratory symptoms should be viewed as potentially serious. Long term sequelae of caustic ingestion are rare and in this series only affected the gastrointestinal tract. The indications for diagnostic endoscopy need further evaluation.

Adolescent↗
PubMed2004

[Barrett's esophagus associated to caustic stenosis of the esophagus].

BACKGROUND: The esophageal stenosis secondary to the ingestion of caustic products is frequent in Brazil, mainly due to an attempt suicide. The Barrett's esophagus is consequence of the chronic gastroesophageal reflux. The literature consulted showed that are a rare association. CASUISTIC AND METHODS: From 1981 to 2000 were admitted and treated in the "Gastrocentro" State University of Campinas, SP, Brazil, 120 patients presenting caustic stenosis of the esophagus, and during the follow-up were found nine cases with Barrett's esophagus associated (7,5%). The time of caustic ingestion varied from 4 years to 54 years (mean 29 years), and they were four males and five females, eight whites and one black, with the mean age of 57,7 years (43 to 72 years). RESULTS: All the cases presented dysphagia and the flexible upper endoscopy showed stenotic areas and caustic esophagitis sequels. Three patients referred symptoms of gastroesophageal reflux, but hiatus hernia were found in only one case. The Barrett's esophagus was found in the middle third of the esophagus above the stenotic areas in three cases, and in the distal third in six cases. The dysphagia was treated with periodic esophageal dilatations. Two patients presenting severe symptoms of reflux were submitted to modified Nissen fundoplication by videolaparoscopy, with good results. CONCLUSIONS: The Barrett's esophagus in these patients could be associated to the caustic ingestion, because it is not situated in the distal third of the esophagus, as commonly found in reflux esophagitis. Its is very important the follow-up and biopsies of the Barrett's esophagus, due to the possibility of malignancy.

Adult↗
PubMed2003

Predictors of esophageal stricture in children with unintentional ingestion of caustic agents.

BACKGROUND: Prediction of the severity of esophageal injury following ingestion of a caustic substance is a challenging problem for clinicians. It was hoped that risk factors for the early prediction of esophageal stricture in such patients could be identified in this study. METHODS: This study comprises an evaluation of 32 children with esophageal injury due to ingestion of caustic materials. Patients' signs and symptoms as well as laboratory data including leukocyte counts and C-reactive protein level were reviewed. RESULTS: Patients who presented with a greater number of symptoms and signs were inclined to have more severe esophageal injury and stricture. The frequency of symptoms and signs in patients with serious esophageal injury was higher than that in patients with low-grade injury. Patients with severe injury were more significantly associated with the occurrence of stricture. The characteristic of caustic ingestion was associated with esophageal stricture, but not esophageal injury. There was no statistically significant difference in leukocyte counts relative to severity of esophageal injury. The mean of leukocyte counts of patients with esophageal stricture was close to that of patients without esophageal stricture. There was also no statistically significant difference in C-reactive protein values between the 2 groups of patients. CONCLUSIONS: Leukocyte counts and C-reactive protein are not useful parameters for predicting the severity of esophageal injury and occurrence of stricture following injury to the esophagus by caustic materials. Alkali ingestion more probably leads to esophageal stricture than acid ingestion. After caustic ingestion, the presence of a greater number of symptoms and signs suggests a more-severe injury, which necessitates more-aggressive management.

Adolescent↗
PubMedDate not supplied

The results of caustic ingestions.

BACKGROUND/AIMS: The ingestion of caustic substances is a common condition, which may result in serious injuries of the upper gastrointestinal system. The purpose of this study is to assess the outcomes of patients who had a history of the ingestion of caustic substances. METHODOLOGY: Between January 1995 and May 2002, 53 patients with clinical and/or endoscopic signs of caustic agents injury admitted to the Emergency Surgery Service of University of Istanbul, Istanbul Medical School, were retrospectively evaluated. RESULTS: The group consisted of 29 females and 24 males with a mean age of 33 years (range 15 to 77). Caustic ingestion was accidental in 31 (59%) and suicidal in 22 (41%). Twenty-five (47%) patients had history of acid ingestions, 21 (40%) alkaline and 7 (12%) unknown agents. The findings of upper gastrointestinal tract endoscopy in 37 patients were as follows: i) fourteen patients had Grade I esophagitis, ii) fourteen patients had Grade II esophagitis; four with gastric mucosal burn, three with gastric and duodenal mucosal burn, five with pharyngeal mucosal burns, iii) two patients had gastric and duodenal mucosal burns, iv) four patients had gastric mucosal burn, vi) three patients had esophageal, gastric and duodenal mucosal burn. Eight patients (15%) with signs of acute abdomen underwent urgent surgery (six of these cases were acid ingestions and seven were suicidal ingestions); four of these patients with esophageal necrosis and gastric perforation, two with esophageal, gastric, duodenal and jejunal necrosis, one with local necrosis in the gastric fundus, and one had normal findings at laparotomy. The mean follow-up period was 11.6 months (range 1 to 42 months). During the follow-up one patient presented with pyloric stenosis, which required surgery. The mortality rate was 11%. CONCLUSIONS: Suicidal caustic ingestion and acid ingestion seem to cause more severe injuries. Early admission to the hospital with clinical and endoscopic evaluation and early surgery when required may reduce morbidity and mortality.

Accidents↗
PubMed2005

Laboratory scale Clean-In-Place (CIP) studies on the effectiveness of different caustic and acid wash steps on the removal of dairy biofilms.

A laboratory scale, bench top flow system was used to partially reproduce dairy plant conditions under which biofilms form and to quantify the effectiveness of caustic and acid wash steps in reducing the number of viable bacteria attached to stainless steel (SS) surfaces. Once bacteria attached to surfaces, a standard clean-in-place (CIP) regime (water rinse, 1% sodium hydroxide at 65 degrees C for 10 min, water rinse, 1.0% nitric acid at 65 degrees C for 10 min, water rinse) did not reproducibly ensure their removal. Standard CIP effectiveness was compared to alternative cleaning chemicals such as: caustic blends (Alkazolv 48, Ultrazolv 700, Concept C20, and Reflex B165); a caustic additive (Eliminator); acid blends (Nitroplus and Nitrobrite); and sanitizer (Perform). The addition of a caustic additive, Eliminator, enhanced biofilm removal compared to the standard CIP regime and further increases in cleaning efficiency occurred when nitric acid was substituted with Nitroplus. The combination of NaOH plus Eliminator and Nitroplus achieved a 3.8 log reduction in the number of cells recovered from the stainless steel surface. The incorporation of a sanitizer step into the CIP did not appear to enhance biofilm removal. This study has shown that the effectiveness of a "standard" CIP can possibly be enhanced through the testing and use of caustic and acid blends. There are many implications of these findings, including: the development of improved cleaning regimes and improved product quality, plant performance, and economic returns.

Analysis of Variance↗
PubMed2004

Pediatric caustic ingestion and parental cocaine abuse.

OBJECTIVE: To report two cases in which toddlers drank a caustic liquid which their parents had been using to prepare free-base and crack cocaine. DESIGN: Case series. RESULTS: Two toddlers presented with first- and second-degree burns of the oral cavity, pharynx and esophagus from caustic ingestion. The first had drunk ammonia from an unmarked clear plastic container the morning after "a party at a friend's house". The second had drunk potassium hydroxide from a clear plastic container which was labelled "pH UP" and had a small "Danger" sign. Both children were treated with intravenous hydration, steroids, antibiotics and analgesics. Fortunately, neither child suffered long-term physical sequelae. When questioned, the parents of both children admitted to using these alkalis to prepare free-base and crack cocaine. Appropriate steps were taken by social services to protect these children from further neglect. DISCUSSION: Despite federal legislation and public education, pediatric caustic ingestion remains a significant problem. These cases suggest that, in certain cases of pediatric caustic ingestion, caregivers should be questioned regarding possible drug abuse. Larger warning labels and further public education might help prevent many cases of pediatric caustic ingestion.

Ammonia↗
PubMed1988

Progressive roentgenographic appearance of caustic esophagitis.

We observed progressive roentgenographic changes in five patients who had caustic esophagitis after accidental ingestion of a liquid alkali. Initial endoscopic examination showed moderate caustic esophagitis in all patients, and esophageal atony and poor distension were early roentgenographic observations. Esophageal strictures developed 13 to 44 days after caustic ingestion in all patients. Intramural pseudodiverticula complicated stricture formation in two patients. Esophageal diverticula developed in two cases, three months to one year after caustic ingestion. In summary, moderate caustic esophagitis is associated with esophageal dilatation, atony, and peristaltic abnormalities initially, and with eventual stricture formation.

Adult↗
PubMed1991

Caustic burns of the upper digestive and respiratory tracts.

In a series of 51 children presenting with an accidental caustic burn, symptoms were analysed for their predictive value of significant i.e. necrotizing oesophageal lesions (grade II or III). For the whole group, the incidence of significant oesophageal lesions was 37%. Vomiting and/or respiratory distress were associated with high incidence of significant oesophageal burn (84% and 75% respectively). The particular location of each caustic burn was analysed for its association with caustic burns at other anatomical sites. Of the 18 patients with a laryngeal burn, 72% also had a grade II or III oesophageal burn. The 19 patients with a grade II or III oesophageal burn and the 18 patients with a laryngeal burn, all had lesions at other sites. In the group of 19 patients with a caustic lesion limited to one site, only 1 patient showed mild oesophagitis (grade I) without late sequelae.

Burns, Chemical↗
PubMed2001

Scintigraphy in the detection of gastro-oesophageal reflux in children with caustic oesophageal burns: a comparative study with radiography and 24-h pH monitoring.

BACKGROUND: Caustic injury of the oesophagus not only causes luminal narrowing but is also responsible for longitudinal contraction, resulting in gastro-oesophageal reflux (GOR), which leads to failure of conventional therapy. Therefore, the development of GOR should be investigated periodically to direct appropriate management of these patients. PURPOSE: To determine the ability of scintigraphy to detect GOR in children with caustic oesophageal strictures in comparison with barium study and 24-h pH monitoring. MATERIALS AND METHODS: Seventeen children with caustic oesophageal injury underwent scintigraphy, an upper GI barium study and 24-h pH monitoring within the same week. Five patients were also investigated post-operatively for the assessment of surgical outcome after antireflux surgery. RESULTS: On the whole, there was good correlation (r = 0.78, P < 0.00 l) between scintigraphy and 24-h oesophageal pH monitoring. Scintigraphy detected all but one (9/10) refluxing patients and also correctly identified all (7/7) non-refluxing patients. Barium studies demonstrated 6 out of 10 refluxing patients. There were no false-positive barium studies in non-refluxing patients. Post-operative studies demonstrated no evidence of GOR in surgically treated patients. CONCLUSIONS: Our results indicate that, by comparison with barium studies, scintigraphy is useful in the detection of GOR in cases with caustic oesophageal strictures and may be used as a screening modality for those under clinical follow-up.

Adolescent↗
PubMed2004

Early bougienage for relief of stricture formation following caustic esophageal burns.

Accidental ingestion of corrosive substances remains a major health hazard in children. Most infants and children who ingest caustic substances present with very few symptoms or signs. Approximately 40% of caustic substance ingestions result in esophageal injury, but the optimal management of caustic esophageal burns remains controversial, with different treatment modalities in use. The aim of this study was to compare the results of prophylactic early bougienage with dilatation that was begun after stricture development. We retrospectively analyzed the management of 125 pediatric cases of corrosive substance ingestion. For children seen primarily at our institution, initial management consisted of prompt endoscopy. Of 125 children admitted with a history of caustic substance ingestion, 54 were found to have esophageal burns, and 32 underwent treatment for stricture formation. Patients with severe injury were divided into two groups: In group A, consisting of 20 patients, prophylactic early dilatation had been done. In the eight patients in group B, dilatation had begun after stricture development. The strictures had resolved after 6 months of dilatation in patients initially treated with prophylactic early bougienage, whereas in patients in whom dilatation began after stricture development, stricture resolution did not occur for more than a year. The goal of initial treatment is to avoid stricture formation. Although early dilatations do not eliminate stricture formation completely, the stricture can resolve more easily with early bougienage.

Adolescent↗
PubMed2004

The effect of halofuginone, a specific inhibitor of collagen type 1 synthesis, in the prevention of esophageal strictures related to caustic injury.

BACKGROUND: To assess the effects of halofuginone, a specific inhibitor of synthesis of collagen type 1, which is the major constituent of fibrosis, on esophageal stricture formation due to caustic ingestion. METHODS: Sixty rats were divided into four equal groups: control group; sham laparotomy group; caustic injury without treatment group; caustic injury with halofuginone treatment group. Caustic injuries were done by 50% sodium hydroxide. Halofuginone was administered by the first postoperative day. All animals were sacrificed on day 21; and the results were evaluated by hydroxyproline levels, stenosis index, lumen diameter, histopathological evaluation, wall thickness, and animal weights. RESULTS: Mortality differences were significant comparing group 3 with group 1 and 2 (P = 0.006) and group 4 (P = 0.03). According to hydroxyproline levels, the differences are significantly higher (P <0.001) comparing group 3 with group 1, 2, and 4. The P value was considered significant in all other parameters (P <0.001) for all the groups but group 1 versus group 2 (P >0.05). CONCLUSIONS: Halofuginone, a specific inhibitor of collagen type 1 synthesis, significantly reduced esophageal stricture occurrence.

Animals↗
PubMed2004

[High doses of steroids in the management of caustic esophageal burns in children].

UNLABELLED: Esophageal burns are frequent in some countries. Esophageal stricture is a severe complication after caustic ingestion. Its frequency is estimated to 5% and reaches 47% in severe esophagitis. AIM OF THE STUDY: To study the influence of management of severe esophageal burns with high doses of steroids in the occurrence of esophageal stricture through the experience of an endoscopic unit. PATIENTS AND METHODS: Twenty-six children with a mean age of 3.5 years (15 months-8 years) with a second b- (N =22) or a third-degree (N =4) esophageal burns due to accidental ingestion of a caustic substance were included between 1993 and 1999. Corrosive substances ingested were sodium hydroxide (N =17), bleach (N =4), alkali (N =3), others (N =2). Upper GI endoscopy was performed in 17 children within the 24 hours of caustic ingestion and within the first 48 hours in all cases. All patients received methylprednisolone (1 g/1.73 m2/day) plus cimetidine and ampicillin plus early oral feeding resumption. RESULTS: Three children (2 grade II et one grade I) were not controlled on day 30 of the protocol and have then been excluded. The remaining 23 children were divided in two groups depending on the upper GI endoscopic results: group I of 12 patients completely or partially healed and group II of 11 patients who developed an esophageal stricture. No difference was observed between the two groups with regard to the delay between caustic ingestion and the start of treatment and the number of shots of methylprednisolone. Second b- degree esophagitis complicated with an esophageal stricture underwent a median of five esophageal dilations (1-12). After a median follow-up of three years, four of them have a normal esophagus. All children with a third-degree esophagitis developed an esophageal stricture. One had a surgical replacement of the esophagus with a segment of colon with good outcome. The three others underwent a median of seven esophageal dilations (5-10). One of them has a normal esophagus after a follow-up of five years while the two others were lost to follow-up. CONCLUSION: High dose of corticosteroids seems to improve second b-degree esophagitis prognosis and may prevent from esophageal stricture.

Burns, Chemical↗
PubMed2004

Potentials of biological oxidation processes for the treatment of spent sulfidic caustics containing thiols.

This research focused on the biological treatment of sulfidic spent caustics from refineries, which contain mainly hydrogen sulfide, methanethiol (MT) and ethanethiol (ET). Also various organic compounds can be present such as BTEX. Biological oxidation of 2.5 mM MT in batch experiments occurred after MT was first auto-oxidized into dimethyldisulfide (DMDS) whereafter oxidation into sulfate was completed in 350 h. DMDS as sole substrate was completely oxidized within 40 h. Therefore, DMDS formation seems to play an important role in detoxification of MT. Biological oxidation of ET and buthanethiol was not successful in batch experiments. Complete oxidation of MT and ET was observed in flow-through reactor experiments. Simultaneous oxidation of sulfide and MT was achieved when treating a synthetic spent caustic, containing 10 mM sulfide and 2.5 mM MT, in a bubble column reactor with carrier material at a hydraulic retention time of 6 h. Addition of 7.5 mM phenol, a common pollutant of spent caustics, did not adversely affect the biological oxidation process and phenol was completely removed from the effluent. Finally, three different spent caustics solutions from refineries were successfully treated.

Biodegradation, Environmental↗