The interpretable machine learning model associated with metal mixtures to identify hypertension via EMR mining method.

There are limited data available regarding the connection between hypertension and heavy metal exposure. The authors intend to establish an interpretable machine learning (ML) model with high efficiency and robustness that identifies hypertension based on heavy metal exposure. Our datasets were obtained from the US National Health and Nutrition Examination Survey (NHANES, 2013-2020.3). The authors developed 5 ML models for hypertension identification by heavy metal exposure, and tested them by 10 discrimination characteristics. Further, the authors chose the optimally performing model after parameter adjustment by Genetic Algorithm (GA) for identification. Finally, in order to visualize the model's ability to make decisions, the authors used SHapley Additive exPlanation (SHAP) and Local Interpretable Model-Agnostic Explanations (LIME) algorithm to illustrate the features. The study included 19 368 participants in total. A best-performing eXtreme Gradient Boosting (XGB) with GA for hypertension identification by 16 heavy metals was selected (AUC: 0.774; 95% CI: 0.772-0.776; accuracy: 87.7%). According to SHAP values, Barium (0.02), Cadmium (0.017), Lead (0.017), Antimony (0.008), Tin (0.007), Manganese (0.006), Thallium (0.004), Tungsten (0.004) in urine, and Lead (0.048), Mercury (0.035), Selenium (0.05), Manganese (0.007) in blood positively influenced the model, while Cadmium (-0.001) in urine negatively influenced the model. Study participants' hypertension associated with heavy metal exposure was identified by an efficient, robust, and interpretable GA-XGB model with SHAP and LIME. Barium, Cadmium, Lead, Antimony, Tin, Manganese, Thallium, Tungsten in urine, and Lead, Mercury, Selenium, Manganese in blood are positively correlated with hypertension, while Cadmium in blood is negatively correlated with hypertension.

Human biomonitoring to assess exposure to thallium following the contamination of drinking water.

In 2014, in some parts of the water distribution system of the municipality of Pietrasanta (Tuscany, Italy), thallium (Tl) levels above the recommended limits were measured and some restrictions to water usage for drinking and food preparation were imposed. The study aimed to assess Tl exposure and possible health effects by means of a human biomonitoring survey. In the 2014-2016 time frame, 2154 urine and 254 hair samples were taken from different population groups and from a control group. The levels of Tl found in urine and hair were statistically higher in exposed groups than in controls and compared to the reference values for the general population. Concentrations in urine were significantly associated with the geographical origin of the sample, the consumption of drinking water and food grown in local gardens. A significant association was found between urine and hair. No positive associations were found between the Tl levels in hair or urine and several self-reported symptoms and health effects, except for sleep disturbance. The study indicates that the concentration of Tl in drinking water can be traced by urine analysis. Urine and hair have proven to be biological matrices that can be effectively used for the evaluation of Tl exposure. To date, the study represents the most extensive human biomonitoring campaign for the evaluation of the Tl exposure available at international level.

[Determination of thallium in the urine with colloidal palladium as the matrix modifier by graphite furnace atomic absorption Spectrometry].

Objective: To instruct a method of determining thallium in the urine by graphite furnace atomic absorption spectrometry(GF-AAS) with colloidal palladium as the matrix modifier. Methods: Urine samples were first diluted and then determined by GF-AAS with colloidal palladium while using thermal sample injection. Results: The optimum volume of colloidal palladium was 6 µl and the best ashing temperature was 600-800 ℃ while the atomization temperature was 1700-1900 ℃ . This method showed a good linearity relationship when the concentration between 0.33 and 50.0 µg/L while the correlation coefficient of standard curve line was 0.9992, and the detection limit was 0.33 µg/L and the recovery rate was between 92.7% and 102.3% with the intra-day precision in the range of 2.55% to 3.66% and the inter-day precision in the range of 1.77% to 3.85%. Conclusion: This method has the advantages of low detect limit, high sensitivity and good precision, and it can be used in the biological monitoring and emergency detecting of workers exposed to thallium.

Determination of thallium in urine, blood, and hair in illicit opioid users in Iran.

CONTEXT: Heavy metals, including thallium and lead, are introduced to illicit drug users' body as a result of using drugs such as cocaine and heroin. OBJECTIVE: This study aimed to determine urine, blood, and hair thallium (Tl) concentrations in illicit opioid users along with the relevant clinical signs and symptoms consistent with thallotoxicosis and to compare them with the corresponding variables in the control non-opioid user group. MATERIALS AND METHODS: This case-control study was conducted on 50 illicit opioid users who had abused opioids continuously for more than a year, referred to Amirie Drug Abuse Treatment Clinic in Kashan, Iran. The control group included 50 non-opioid users. Thallium concentrations in urine, blood, and hair were assessed in both groups (n = 100) using electrothermal (graphite furnace) atomic absorption spectrometry (ET AAS, GF AAS). RESULTS: In the studied group, the median (interquartile range) concentrations of thallium in urine, blood, and hair were 54.8 ± 79.9 µg/L, 14.5 ± 11.1 µg/L, and 5.4 ± 3.7 µg/g, respectively; these values were 4.8 ± 5.2 µg/L, 2.5 ± 2.4 µg/L, and 1.4 ± 1.1 µg/g, respectively, in the control group. There were significant differences in urine, blood, and hair thallium concentrations between the study group and the control group (p < 0.001). There were significant correlations between duration of illicit opioid use and urine thallium concentrations (r = 0.394, p = 0.005) and hair thallium concentrations (r = 0.293, p = 0.039), but not with blood thallium concentrations (r = 0.246, p = 0.085). Urine and blood thallium concentrations of illicit opioid users with clinical signs and symptoms consistent with thallotoxicosis of weakness (p = 0.01), depression (p = 0.03), and headache (p = 0.03) were higher than users without these problems. DISCUSSION AND CONCLUSION: The results of the study showed that thallium concentrations in urine, blood, and hair in illicit opioid users were significantly higher than the comparable concentrations in the control group. This can be due to the use of illicit opioids adulterated with thallium. Also, this study showed long-term illicit opioid use may lead to thallium exposure. In addition, cigarette smoking was associated with increased thallium exposure.

Thallium exposure at low concentration leads to early damage on multiple organs in children: A case study followed-up for four years.

Thallium (TI) is one of the most toxic heavy metals and priority pollutant metals. The emerging TI environmental pollution worldwide has posed a great threat to human health. However, based on the World Health Organization (WHO), the risk and severity of adverse health effects of TI in the range of 5-500 µg/L are uncertain. Moreover, evidence regarding the adverse impacts of TI on children's health is still insufficient. Herein, we aim to investigate the early adverse effects of TI on children's health and provide references for the WHO to establish stricter safety limits of TI. From 2015 to 2019, urinary TI and many clinical laboratory parameters related to blood routine, hepatic, renal, myocardial, coagulation function and serum electrolyte were measured in six children aged 1-9 years. The urinary TI concentration ranged from 13.4 µg/L to 60.1 µg/L with a mean of 36.1 µg/L and a median of 34.8 µg/L in six children in 2015. Although only four children felt a little poor appetite, several laboratory abnormalities indicated early damage in liver, renal, and myocardial functions in all children in 2015. After treatment and following up for four years, although the children's TI concentration decreased below 5 µg/L, their liver and renal functions did not completely recover, and their myocardial function worsened. Results indicated that impaired liver, renal, and myocardial functions were closely associated with elevated urinary TI concentration in children. Considering the increasing use of TI in high-technology industries and emerging TI environmental-contamination zones worldwide, establishing stricter safety limits of TI and paying more attention to the adverse health effects of TI on children are urgently required. SUMMARY: We found that a relatively low concentration of thallium (13.4 µg/L to 60.1 µg/L) impaired liver, renal, and myocardial function in six children. After treatment and following up these children for four years, although their urinary TI concentration decreased below 5 µg/L, their liver and renal functions did not completely recover, and their myocardial function worsened.

Clinical characteristics and treatment of thallium poisoning in patients with delayed admission in China.

Thallium is highly toxic and its effects are cumulative. The clinical symptoms of thallium poisoning are non-specific, thereby delaying admission and treatment. This study aimed to summarize the clinical features and treatment experience of patients with delayed admission who experience thallium poisoning.We conducted a retrospective descriptive analysis of patients in our hospital from 2008 to 2018 who had thallium poisoning and experienced a delay in hospital admission. The time from symptom onset to admission was assessed. The patients were divided into 3 groups and descriptive analyses of their clinical characteristics, including basic patient information, symptoms, laboratory test results, examination findings, treatment methods, outcomes, and follow-up information, were conducted.A total of 34 patients with thallium poisoning were included: 8 were admitted to the hospital early or with mild delay, 9 had a moderate delay, and 17 had a severely delayed admission. The time from illness onset to admission was 13 (interquartile range, 7.5-26) days. Some patients with delayed admission had significant symptoms associated with central nervous system damage, and changes in magnetic resonance images and electroencephalograms were also noted. After admission, all patients received Prussian blue treatment, and some patients with relatively high blood concentration received blood purification treatments. Following treatment, the blood and urine thallium concentrations of all patients decreased significantly, and their symptoms were alleviated.Our results show that delayed patient admission in cases of thallium poisoning is associated with greater risk of central nervous system damage. Use of Prussian blue combined with blood purification treatments might improve patients' conditions.

Successful treatment of a patient with severe thallium poisoning in a coma using Prussian blue and plasma exchange: A case report.

RATIONALE: This is the first reported severe thallium poisoning patient successfully treated with Prussian blue (PB) and plasma exchange (PE). PATIENT CONCERNS: A 42-year-old woman in a coma owing to severe thallium poisoning was admitted to our department after day 44 of poisoning. At admission, blood and urine thallium concentrations were 380.0 and 2580.0 ng/mL, respectively. DIAGNOSIS: The patient was diagnosed with toxic encephalopathy induced by thallium poisoning; in addition, she was also diagnosed with bilateral pneumonia, respiratory failure, moderate anemia, hypoproteinemia, and electrolyte imbalance based on her chest X-ray, blood gas analysis, Hb level, albumin levels, and serum electrolyte results. INTERVENTIONS: The patient was intubated and treated with PB (6600 mg/d, 15 days in total) combined with PE (once daily, 5 days in total) as well as other symptomatic supportive care measures. OUTCOMES: After treatments, her blood and urinary thallium concentrations gradually decreased and on the 13th day after admission, the blood thallium concentration decreased to 0 ng/mL. The oxygenation index gradually improved, meantime, the patient gradually regained consciousness, and on the 50th day of admission, the patient's consciousness reverted to a clear-headed state. The patient recovered mostly after 37 months of follow-up. LESSONS: Through this case, we learned that the gradual reduction in blood and urine thallium concentration and the patient's improved condition is correlated with PB and PE treatment. For patients with severe thallium poisoning, this treatment method might be effective; but the exact curative effect is unconfirmed, requiring further research to verify.

Examining of Thallium in Cigarette Smokers.

Smoking is one of the sources of thallium which is considered as a toxic heavy metal. The aim of this study was to determine urinary thallium levels and related variables in smokers, compared to a control group. The study was conducted on 56 participants who had smoked continuously during the year before they were referred to Kashan Smoking Cessation Clinic. Fifty-three nonsmokers who were family members or friends of the smokers were selected as the control group. Urinary thallium was measured in both groups (n = 109) using atomic absorption spectrophotometry. The mean value (with SD) for urinary thallium in the smokers (10.16 ± 1.82 µg/L) was significantly higher than in the control group (2.39 ± 0.63 µg/L). There was a significant relationship between smoking duration and urinary thallium levels (P = 0.003). In a subgroup of smokers who was addicted to opium and opium residues (n = 9), the mean level of thallium (37.5 ± 13.09 µg/L) was significantly higher than in the other smokers (4.93 ± 4.45; P = 0.001). Multiple regression analysis showed opioid abuse, insomnia, and chronic obstructive pulmonary disease (COPD), together were strong predictors of urinary thallium levels in smokers. There was no significant difference in thallium level in hookah smokers (P = 0.299) or in those with COPD compared to other smokers (P = 0.375). Urinary thallium levels of smokers with clinical signs of depression, sleep disorders, memory loss, and sweating were higher than those of smokers without these signs. Since thallium, as other toxic metals is accumulated in the body, and cigarette smoking also involves carcinogenic exposures and health hazards for passively exposed people, the need for cigarette control policies is emphasized.

Metals in Urine and Diabetes in U.S. Adults.

UNLABELLED: Our objective was to evaluate the relationship of urine metals including barium, cadmium, cobalt, cesium, molybdenum, lead, antimony, thallium, tungsten, and uranium with diabetes prevalence. Data were from a cross-sectional study of 9,447 participants of the 1999-2010 National Health and Nutrition Examination Survey, a representative sample of the U.S. civilian noninstitutionalized population. Metals were measured in a spot urine sample, and diabetes status was determined based on a previous diagnosis or an A1C ≥6.5% (48 mmol/mol). After multivariable adjustment, the odds ratios of diabetes associated with the highest quartile of metal, compared with the lowest quartile, were 0.86 (95% CI 0.66-1.12) for barium (Ptrend = 0.13), 0.74 (0.51-1.09) for cadmium (Ptrend = 0.35), 1.21 (0.85-1.72) for cobalt (Ptrend = 0.59), 1.31 (0.90-1.91) for cesium (Ptrend = 0.29), 1.76 (1.24-2.50) for molybdenum (Ptrend = 0.01), 0.79 (0.56-1.13) for lead (Ptrend = 0.10), 1.72 (1.27-2.33) for antimony (Ptrend < 0.01), 0.76 (0.51-1.13) for thallium (Ptrend = 0.13), 2.18 (1.51-3.15) for tungsten (Ptrend < 0.01), and 1.46 (1.09-1.96) for uranium (Ptrend = 0.02). Higher quartiles of barium, molybdenum, and antimony were associated with greater HOMA of insulin resistance after adjustment. Molybdenum, antimony, tungsten, and uranium were positively associated with diabetes, even at the relatively low levels seen in the U.S. POPULATION: Prospective studies should further evaluate metals as risk factors for diabetes.

Chelation of thallium by combining deferasirox and desferrioxamine in rats.

The hypothesis that two known chelators deferasirox (4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid) and desferrioxamine (DFO) might be more efficient as combined treatment than as monotherapies in removing thallium from the body was tested in a new acute rat model. 7-week-old male Wistar rats received chelators: deferasirox (orally), DFO (intraperitoneal; i.p.), or deferasirox + DFO as 75 or 150 mg/kg dose half an hour after a single i.p. administration of 8 mg thallium/kg body weight in the form of chloride. Serum thallium concentration, urinary thallium, and iron excretions were determined by graphite furnace atomic absorption spectrometry. Both chelators were effective only at the higher dose level, while DFO was more effective than deferasirox in enhancing urinary thallium excretion, deferasirox was more effective than DFO in enhancing urinary iron excretion. In the combined treatment group, deferasirox did not increase the DFO effect on thallium and DFO did not increase the effect of deferasirox on iron elimination. Our results support the usefulness of this animal model for preliminary in vivo testing of thallium chelators. Urinary values were more useful because of the high variability of serum results.

Thallium exists in opioid poisoned patients.

BACKGROUND: Thallium (Tl) is a toxic heavy metal that exists in nature. Tl poisoning (thallotoxicosis) may occur in opioid addicts. This study was designed to evaluate the frequency and level of urinary Tl in opioid abusers. In addition, clinical findings were evaluated. METHODS: A total of 150 subjects were examined. Cases with a history of at least 3 years of abuse were admitted in the Imam Reza Hospital as the case group; 50 non-opioid abusers from the target population were included as the control group. Twenty-four hour urinary qualitative and quantitative Tl analyses were performed on both groups. RESULTS: Out of the 150 subjects, 128 (85 %) were negative for qualitative urinary Tl, followed by 5 % (trace), 7 % (1+), 2 % (2+), and 1 % (3+). Mean (standard error (SE), Min-Max) quantitative urinary Tl level was 14 µg/L (3.5 µg/L, 0-346 µg/L). Mean urinary Tl level in the case group was 21 µg/L (5 µg/L, 0-346 µg/L) and that in the controls was 1 µg/L (0.14 µg/L, 0-26 µg/L), which were significantly different (P = 0.001). The most frequent clinical findings were ataxia (86 %), sweating (81 %), and constipation (54 %). In all cases (n = 150), the mean (SE) value for cases with positive qualitative urinary Tl was 26.8 µg/L (0.9 µg/L) and that in the negative cases was 2.3 µg/L (0.2 µg/L), which were significantly different (P = 0.002). CONCLUSIONS: This study showed that long-term opioid abuse may lead to Tl exposure. In opioid abusers with the clinical manifestation of thallotoxicosis, urinary Tl should be determined.

Comparison of urinary thallium levels in non-occupationally exposed people and workers.

PURPOSE: To determine a reference background urinary thallium level; to compare urinary thallium data from workers to this background level; to investigate factors affecting these levels and whether creatinine correction is appropriate. METHODS: Urine samples from non-occupationally exposed people (n = 273, from 113 individuals) and workers (n = 896, from 447 individuals) were analysed for thallium by ICP-MS. A reference background level was calculated, defined as the 95th percentile value of a non-occupationally exposed population. Worker data were divided into two subsets: thallium workers (those who work directly with thallium or its compounds) and general workers; and compared to the background level. Bayesian linear mixed effects modelling was used to investigate factors affecting urinary thallium concentration and the efficacy of creatinine correction for the determination of urinary thallium. RESULTS: The reference background urinary thallium level is 0.27 µmol/mol creatinine (creatinine-corrected) or 0.40 µg/l (uncorrected). Median values were 0.11 µmol/mol creatinine or 0.17 µg/l for non-occupationally exposed people, 0.12 µmol/mol creatinine or 0.20 µg/l for general workers and 0.19 µmol/mol creatinine or 0.41 µg/l for thallium workers. Variation was lower in creatinine-corrected models. Nine per cent of samples from general workers and 39 % of samples from thallium workers exceeded the creatinine-corrected background level. By 2010, 90 % of all workers had urinary thallium levels below the 95th percentile reference background level. CONCLUSIONS: Urinary thallium concentrations were higher in thallium workers than non-occupationally exposed people and general workers. Creatinine correction is appropriate.

Determination of thallium at ultra-trace levels in water and biological samples using solid phase spectrophotometry.

A new simple, very sensitive, selective and accurate procedure for the determination of trace amounts of thallium(III) by solid-phase spectrophotometry (SPS) has been developed. The procedure is based on fixation of Tl(III) as quinalizarin ion associate on a styrene-divinylbenzene anion-exchange resin. The absorbance of resin sorbed Tl(III) ion associate is measured directly at 636 and 830 nm. Thallium(I) was determined by difference measurements after oxidation of Tl(I) to Tl(III) with bromine. Calibration is linear over the range 0.5-12.0 µg L(-1) of Tl(III) with relative standard deviation (RSD) of 1.40% (n=10). The detection and quantification limits are 150 and 495 ng L(-1) using 0.6 g of the exchanger. The molar absorptivity and Sandell sensitivity are also calculated and found to be 1.31×10(7) L mol(-1)cm(-1) and 0.00156 ng cm(-2), respectively. The proposed procedure has been successfully applied to determine thallium in water, urine and serum samples.

A fatal case of thallium toxicity: challenges in management.

BACKGROUND: Thallium is a highly toxic compound and is occasionally involved in intentional overdoses or criminal poisonings. Accidental poisonings also occur, but are increasingly rare owing to restricted use and availability of thallium. We report a fatal suicidal ingestion of thallium sulfate rodenticide in which multi-dose activated charcoal (MDAC) and Prussian Blue (PB) were both used without changing the outcome. CASE REPORT: A 36 year old man ingested an unknown amount of thallium sulfate grains from an old rodenticide bottle. He presented to an emergency department (ED) 45 minutes later with abdominal pain and vomiting. On examination he was agitated with a blood pressure of 141/60 mmHg and a heart rate of 146 beats per minute (bpm). He received MDAC during his initial ED management and was started on PB 18 hours post arrival; he was intubated on the following day for airway protection. The patient continued to be tachycardic and hypertensive and subsequently developed renal failure. On hospital day three, the patient developed hypotension that did not respond to fluids. The patient required vasopressors and was transferred to a tertiary care center to undergo continuous renal replacement therapy (CRRT). The patient died shortly after his transfer. His last blood thallium concentration was 5369 mcg/L, a spot urine thallium >2000 mcg/L, and a 24- hour urine thallium was >2000 mcg/L. CONCLUSION: Though extremely rare, thallium intoxication can be lethal despite early administration of MDAC and use of Prussian blue therapy. Rapid initiation of hemodialysis can be considered in cases of severe thallium poisoning, to remove additional thallium, to correct acid-base disturbance, or to improve renal function.

Toxicological status of children with autism vs. neurotypical children and the association with autism severity.

This study investigates both the level of toxic metals in children with autism and the possible association of those toxic metals with autism severity. This study involved 55 children with autism ages 5-16 years compared to 44 controls with similar age and gender. The study included measurements of toxic metals in whole blood, red blood cells (RBC), and urine. The autism group had higher levels of lead in RBC (+41 %, p = 0.002) and higher urinary levels of lead (+74 %, p = 0.02), thallium (+77 %, p = 0.0001), tin (+115 %, p = 0.01), and tungsten (+44 %, p = 0.00005). However, the autism group had slightly lower levels of cadmium in whole blood (-19 %, p = 0.003). A stepwise, multiple linear regression analysis found a strong association of levels of toxic metals with variation in the degree of severity of autism for all the severity scales (adjusted R(2) of 0.38-0.47, p < 0.0003). Cadmium (whole blood) and mercury (whole blood and RBC) were the most consistently significant variables. Overall, children with autism have higher average levels of several toxic metals, and levels of several toxic metals are strongly associated with variations in the severity of autism for all three of the autism severity scales investigated.

Associations of multiple metals with kidney outcomes in lead workers.

OBJECTIVES: Environmental exposure to multiple metals is common. A number of metals cause nephrotoxicity with acute and/or chronic exposure. However, few epidemiologic studies have examined the impact of metal coexposure on kidney function. Therefore, the authors evaluated associations of antimony and thallium with kidney outcomes and assessed the impact of cadmium exposure on those associations in lead workers. METHODS: Multiple linear regression was used to examine associations between ln-urine thallium, antimony and cadmium levels with serum creatinine- and cystatin-C-based glomerular filtration measures and ln-urine N-acetyl-ß-D-glucosaminidase (NAG). RESULTS: In 684 participants, median urine thallium and antimony were 0.39 and 0.36 µg/g creatinine, respectively. After adjustment for lead dose, urine creatinine and kidney risk factors, higher ln-urine thallium was associated with higher serum creatinine- and cystatin-C-based estimates of glomerular filtration rate; associations remained significant after adjustment for antimony and cadmium (regression coefficient for serum creatinine-based estimates of glomerular filtration rate =5.2 ml/min/1.73 m2; 95% CI =2.4 to 8.0). Antimony associations with kidney outcomes were attenuated by thallium and cadmium adjustment; thallium and antimony associations with NAG were attenuated by cadmium. CONCLUSIONS: Urine thallium levels were significantly associated with both serum creatinine- and cystatin-C-based glomerular filtration measures in a direction opposite that expected with nephrotoxicity. Given similarities to associations recently observed with cadmium, these results suggest that interpretation of urine metal values, at exposure levels currently present in the environment, may be more complex than previously appreciated. These results also support multiple metal analysis approaches to decrease the potential for inaccurate risk conclusions.

Management of thallium poisoning in patients with delayed hospital admission.

OBJECTIVE: To describe the clinical features and management of thallium poisoning in patients with delayed hospital admission. METHODS: Fourteen patients (median age 36 years) were admitted 9-19 days after ingesting food poisoned with thallium. Clinical and laboratory data, including blood and urine thallium concentrations, were collected. Patients were treated with oral Prussian blue, a chelating agent sodium dimercaptosulfonate, and hemodialysis. RESULTS: All patients experienced a triad of symptoms of acute gastrointestinal upset, painful combined polyneuropathy, and hair loss after consuming poisoned food. Fatigue and skin pigmentation were observed in all patients. Abnormal liver function tests were found in 6 (42.9%) and delirium and coma were identified in 4 (28.6%). Two weeks after the poisoning, the blood and urine thallium concentration ranged from 219.0 to 1414.4 µg/L (median: 535.3) and 956.5 to 11285.0 µg/L (median: 7460.0), respectively. One patient (7.1%) with a previous history of pulmonary fibrosis died of respiratory failure in hospital. Symptoms were improved and blood or urine thallium levels were normalized in the remaining 13 patients before discharge. After a 6.5 ± 1-month follow-up, 1 patient (7.1%) developed deep venous thrombosis in the left lower limb. In another patient (7.1%), numbness in the lower limbs remained. CONCLUSION: Acute thallium poisoning is commonly manifested by gastrointestinal upset, painful polyneuropathy, and significant hair loss. Treatment strategies included Prussian blue and hemodialysis, which were associated with a good outcome in this case series.

Thallium pollution in China: A geo-environmental perspective.

It is well known that thallium (Tl) is a non-essential and toxic metal to human health, but less is known about the geo-environmentally-induced Tl pollution and its associated health impacts. High concentrations of Tl that are primarily associated with the epithermal metallogenesis of sulfide minerals have the potential of producing Tl pollution in the environment, which has been recognized as an emerging pollutant in China. This paper aims to review the research progress in China on Tl pollution in terms of the source, mobility, transportation pathway, and health exposure of Tl and to address the environmental concerns on Tl pollution in a geo-environmental perspective. Tl associated with the epithermal metallogenesis of sulfide minerals has been documented to disperse readily and accumulate through the geo-environmental processes of soil enrichment, water transportation and food crop growth beyond a mineralized zone. The enrichments of Tl in local soil, water, and crops may result in Tl pollution and consequent adverse health effects, e.g. chronic Tl poisoning. Investigation of the baseline Tl in the geo-environment, proper land use and health-related environmental planning and regulation are critical to prevent the Tl pollution. Examination of the human urinary Tl concentration is a quick approach to identify exposure of Tl pollution to humans. The experiences of Tl pollution in China can provide important lessons for many other regions in the world with similar geo-environmental contexts because of the high mobility and toxicity of Tl.

[Thallium content in adults older than 45 ages at Hezhang County of Guizhou Province].

OBJECTIVE: To investigate the feature of Thallium content in adults of heavy metal contaminated district due to mining of Hezhang County, Guizhou Province. METHODS The subjects older than 45 ages were randomly recruited from the mineralized district (Magu village) and no-mineralized district (Salaxi viillage) , urine of villagers were collected and thallium content in urine were detected with ICP-MS. RESULTS: The average thallium contents in urine of Magu villagers were higner than those of Salaxi villagers,The urinary thallium contents of female were higner than those of male. The urinary thallium contents of residents in two districts were mostly under the upper limit of exposure in human bodies. CONCLUSION: There was no villager suffered from chronic poisoning of thallium in the two observing districts, the 95% upper limits of urinary thallium content for nonoccupational women older than 45 ages in Magu village was 8 microg/gCr and those for other nonoccupational subjects older than 45 ages was 5 microg/gCr.