Helical CT versus intermittent CT fluoroscopic guidance for musculoskeletal needle biopsies: impact on radiation exposure, procedure time, diagnostic yield, and adverse events.

OBJECTIVE: Image-guided percutaneous needle biopsies are essential in the workup of musculoskeletal (MSK) lesions. While helical CT (HCT) is well established, intermittent CT fluoroscopy (iCTF) is an increasingly used alternative. The purpose of this study is to establish whether differences in subject radiation exposure, procedure time, yield, or adverse events exist between HCT and iCTF guidance. MATERIALS AND METHODS: This retrospective cohort study included consecutive MSK needle biopsies performed on a single-CT scanner over a 12-month period at a tertiary academic center. Subject demographics, radiation dose, and outcomes were abstracted from the medical record. Comparisons between the two cohorts were performed using Student's t-test for continuous data and using Fisher's exact test for categorical data and a two-tailed p value less than 0.05 was considered significant. RESULTS: Two hundred sixteen adults (115 (53.2%) females) with a mean age of 58.8 ± 18.4 years, underwent 216 biopsies (109 (50.5%) HCT guided, 107 (49.5%) iCTF guided) between June 2017 and June 2018. Dose-length product (DLP) and volume CT dose index (CTDIvol) were significantly higher for the HCT cohort (HCT 698.9 ± 400.8 mGycm vs iCTF 312.8 ± 170.8 mGycm; p < 0.005 and HCT 19.1 mGy ± 8.8 vs iCTF 6.9 mGy ± 1.5, p < 0.001). No significant difference in diagnostic yield, procedure time, or adverse event rate was identified. CONCLUSION: For CT-guided MSK needle biopsies, iCTF decreases subject radiation dose compared to HCT without negatively affecting outcomes. iCTF should be strongly considered by radiologists performing MSK biopsies given the reduced patient radiation exposure.

Invasive salmonella enteritidis infection complicated by colonic perforations and pancytopenia: A case report.

Salmonellosis caused by bacterial genus Salmonella is associated with a high morbidity and mortality rate. Salmonellae can be divided into typhoidal serotypes (S. enterica ser. Typhi and S. enterica ser. Paratyphi A) and nontyphoidal Salmonella (NTS) serotypes. The two most common NTS serotypes isolated from human sources were S. enterica ser. Typhimurium and S. enterica ser. Enteritidis. NTS infection can present with diverse clinical manifestations, including gastroenteritis, bacteraemia, septic arthritis, osteomyelitis, and endovascular infection. Intestinal perforation is an extremely rare and potentially fatal complication of severe salmonella infection. Herein, we report a case of invasive S. Enteritidis infection complicated by colonic perforation and pancytopenia. Following a colonic resection, the patient received a prolonged course of antimicrobial therapy and eventually recovered.

Clinical severity of COVID-19 with omicron variant predominance in relation to vaccination status, age, comorbidities- a single center in Selangor, Malaysia.

INTRODUCTION: Recently, the rapid surge of reported COVID-19 cases attributed to the Omicron variant of severe acute respiratory syndrome coronavirus (SARS-CoV-2) created an immediate concern across nations. Local information pertaining to the new variant of concern (VOC) is lacking. We aimed to determine the clinical characteristics of COVID-19 during a period of Omicron prevalence among patients hospitalised from February 1 to 21, 2022 at Sungai Buloh Hospital and to estimate the risks of disease progression presumably caused by this variant in association with gender, age, comorbidity, and vaccination status. MATERIALS AND METHODS: In this retrospective, singlecentered, retrospective cohort study, all hospitalised adults with laboratory-confirmed COVID-19, aged 18 and above, were recruited from February 1 to 21, 2022. Clinical characteristics, investigations, and outcomes were assessed. RESULTS: A total of 2279 patients aged 18 years and above with laboratory-proven COVID-19 were recruited and analysed, excluding 32 patients owing to incomplete data. Majority of the study population had a mean age of 41.8 ± 17.7, was female-predominant (1329/2279, 58.6%), had completed a primary series of vaccination with a booster (1103/2279, 48.4%), and had no underlying medical conditions (1529/2279, 67.4%). The risk of COVID-19-related disease progression was significantly lower in hospitalised patients under the age of 50 who were female, had no comorbidity, and had completed two doses of the primary series with or without a booster. [respectively, OR 7.94 (95% CI 6.16, 10.23); 1.68 (1.34, 2,12); 2.44 (1.85, 3.22); 2.56 (1.65, 3.97), p< 0.001]. CONCLUSION: During the period of Omicron prevalence, a favourable outcome of COVID-19 was strongly associated with female gender, age below 50, a comorbidity-free condition, and having completed immunization. With this new observation, it could help improve public health planning and clinical management in response to the emergence of the latest VOC.

CT-guided bone marrow aspirations and biopsies: retrospective study and comparison with blind procedures.

PURPOSE: To compare the pathology results of CT-guided and blind bone marrow aspirations and biopsies. METHODS: Ninety-eight consecutive CT-guided biopsies and 98 age- and gender-matched blind (non-CT-guided) posterior iliac crest bone marrow aspirations and biopsies performed in 2017 were reviewed for adequacy of core biopsies and aspirate smears. CT procedure images and CT abdomen/pelvis images were reviewed to evaluate anatomic features of the posterior ilium and soft tissues. Statistical analysis was performed using a T test, Fisher exact test, and Kruskal-Wallis test. RESULTS: There was no significant difference in the age and gender of the two groups (p > 0.05). However, the CT-guided group had a higher BMI (p = 0.0049) and posterior soft tissue thickness (p = 0.0016). More CT-guided biopsy samples (CT 93 (95%); blind 77 (79%); p = 0.0006) and aspirate smears (CT 90 (92%); blind 78 (80%); p = 0.042) were categorized as adequate. The CT-guided group had longer core lengths (CT 1.4 ± 0.6 (range 0.3-3.5) cm; blind 1.0 ± 0.60 (range 0-2.6) cm; p = 0.0001). Overall, 131/164 (80%) of the cases had at least one of the described features (slanted posterior ilium (angle > 30°), 30%; rounded posterior ilium, 20%; thick posterior ilium cortex, 13%; focal lesion in posterior ilium, 12%; prior procedure in posterior ilium, 5%; posterior soft tissue thickness > 3 cm, 40%). CONCLUSION: CT-guided bone marrow procedures were more likely to result in both adequate aspirate smears and biopsy samples and longer core lengths when compared with blind procedures.

Are vital sign abnormalities associated with poor outcomes after emergency department discharge?

To examine association between vital sign abnormalities in the emergency department (ED) and early death after ED discharge, we performed a matched case-control study. Conditional logistic regression showed that presence of any vital sign abnormality at ED discharge was significantly associated with over three-fold increase in likelihood of death within 15 days of ED discharge (OR: 3.06, 95%CI: 2.81-4.48). Even small changes were associated with increased risk: every additional beat increase in heart rate conferred additional risk (OR: 1.04, 95%CI: 1.02-1.06), while every additional oxygen saturation percentage point was protective (0.89, 0.80-0.98). However, none of these vital sign abnormalities was a good predictor of early death; there was poor discrimination and substantial overlap in values between cases and controls.

The Impact of the Shallow-Trench Isolation Effect on Flicker Noise of Source Follower MOSFETs in a CMOS Image Sensor.

The flicker noise of source follower transistors is the dominant noise source in image sensors. This paper reports a systematic study of the shallow trench isolation effect in transistors with different sizes under high temperature conditions that correspond to the quantity of empty defect sites. The effects of shallow trench isolation sidewall defects on flicker noise characteristics are investigated. In addition, the low-frequency noise and subthreshold swing degrade simultaneously in accordance to the device gate width scaling. Both serious subthreshold leakage and considerable noise can be attributed to the high trap density near the STI edge. Consequently, we propose a coincidental relationship between the noise level and the subthreshold characteristic; its trend is identical to the experiments and simulation results.

Dose reduction for fluoroscopically guided injections: phantom simulation and patient procedures.

OBJECTIVE: To demonstrate fluoroscopy dose reduction through both simulated injections on a phantom and patient injections. MATERIALS AND METHODS: Our study was IRB-approved and HIPAA-compliant. Simulation on a phantom was used to estimate effective dose, entrance dose, and organ doses for hip joint injections without and with dose minimization technique (DMT). Additionally, 1,094 joint, bursae, and tendon sheath injections performed by three operators in the same fluoroscopy suite were evaluated both before and after application of DMT. Fluoroscopy time (FT), dose, and dose area product (DAP) of injections were compared using unpaired t-tests with P > 0.05 considered statistically significant. RESULTS: For the phantom simulation comparing injections without DMT and with DMT, the total DAP was 191.7 vs 18.7 µGy·m2, and the entrance dose was 10.2 vs 3.6 mGy, respectively. For both men and women, DMT reduces effective dose and organ doses. For all injections, the FT (0.7 to 0.2 min), dose (5.6 to 1.9 mGy), and DAP (56.9 to 19.1 µGy·m2) for all three operators decreased with DMT and remained statistically significant when stratified by the two most common injections, glenohumeral and hip joint injections (P < 0.05). CONCLUSIONS: FT, effective dose, entrance dose, and DAP can be reduced with the use of simple easy-to-learn techniques, which will benefit both the patient and the radiologist.

Multistate intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity.

We observe experimentally two regimes of intermittency on the route to chaos of a semiconductor laser subjected to optical feedback from a long external cavity as the feedback level is increased. The first regime encountered corresponds to multistate intermittency involving two or three states composed of several combinations of periodic, quasiperiodic, and subharmonic dynamics. The second regime is observed for larger feedback levels and involves intermittency between period-doubled and chaotic regimes. This latter type of intermittency displays statistical properties similar to those of on-off intermittency.

Prevalence and severity by age and other clinical correlates of haemophilic arthropathy of the elbow, knee and ankle among Taiwanese patients with haemophilia.

INTRODUCTION & AIMS: Haemophilic arthropathy (HA) is a major complication in patients with haemophilia (PWH), but the study of age-specific prevalence and severity of HA is very limited in Asian countries. MATERIALS & METHODS: This study retrospectively reviewed 146 severe- and moderate-type Taiwanese PWH aged 4-73 years, with roentgenograms of elbows, knees and ankles and calculated Pettersson scores. RESULTS: The prevalence of HA, mean number of HAs per patient and mean Pettersson scores of all the joints were 42.8%, 1.3 and 1.9 points in PWH aged 4-10 years; 64.3%, 1.4 and 4.1 points in PWH aged 11-19 years; 97.1%, 2.9 and 15.6 points in PWH aged 20-29 years; 93.1%, 4.4 and 33.1 points in PWH aged 30-39 years; 100%, 5.1 and 46.1 points in PWH aged 40-49 years and 100%, 5 and 49.6 points in PWH aged ≥50 years, respectively. There was a high prevalence of HA for PWH aged ≥20 years. Among PWH aged <20 years, prevalence of HA was low and mild ankle arthropathy was the most common. Besides, in the four age groups aged <40 years, the prevalence of ankle arthropathy was the highest, followed by elbow arthropathy and then knee arthropathy. CONCLUSIONS: Although severe arthropathy of the six major joints was rare in PWH aged <30 years, it increased rapidly in PWH after 30 years. Analysis of clinical correlates suggested that age, severity of haemophilia, absence of prophylaxis and presence of HCV infection correlated positively with Pettersson scores.

Cognitive impairment and hippocampal atrophy in chronic kidney disease.

BACKGROUND: Cognition impairment is well known in patients with chronic kidney disease (CKD). The relationship between brain structure and cognitive performance in CKD patients is still under investigation. The study aimed to quantitatively assess the relationship between brain structure and cognitive performance in patients with CKD. METHODS: We recruited 39 patients with CKD and 39 age- and sex-matched control participants from a tertiary medical center. All participants underwent 3-T MRI scan neuropsychological assessments, and renal function tests. FreeSurfer software was used for imaging processing and analysis, including measurement of cortical thickness and gray matter (GM) and white matter volumes. RESULTS: Compared with control subjects (73.1±7.5 years old), patients with CKD (76.4±8.4 years old) had significantly lower scores on the Mini-Mental State Examination, and forward digit span test (P<.01). Patients with CKD had smaller cerebral GM volume, hippocampus, and decreased cortical thickness (P<.01) relative to the control group. Estimated glomerular filtration rate (eGFR) was correlated with cognitive performance, cortical thickness, GM volume, and hippocampal volume (P<.001). Linear regression analysis revealed that eGFR and GM volume were independently negatively associated with cognitive performance (P<.001), while eGFR and age were negatively associated with cortical thinning and GM volume after controlling for confounding factors. CONCLUSIONS: This study demonstrated that impaired kidney function is associated not only with poor cognitive performance, but also with small cerebral GM volume and reduced cortical thickness.

The mortality and direct medical costs of osteoporotic fractures among postmenopausal women in Taiwan.

UNLABELLED: This study estimated the fracture-related mortality and direct medical costs among postmenopausal women in Taiwan by fracture types and age groups by utilizing a nationwide population-based database. Results demonstrated that hip fractures constituted the most severe and expensive complication of osteoporosis across fracture sites. INTRODUCTION: The aims of the study were to evaluate the risk of death and direct medical costs associated with osteoporotic fractures by fracture types and age groups among postmenopausal women in Taiwan. METHODS: This nationwide, population-based study was based on data from the National Health Insurance Research Database in Taiwan. Female patients aged 50 years and older in the fracture case cohort were matched in 1:1 ratio with randomly selected subjects in the reference control cohort by age, income-related insurance amount, urbanization level, and the Charlson comorbidity index. There were two main outcome measures of the study: age-differentiated mortality and direct medical costs in the first and subsequent years after osteoporotic fracture events among postmenopausal women. The bootstrap method by resampling with replacement was conducted to generate descriptive statistics of mortality and direct medical costs of the case and control cohorts. Student's t tests were then performed to compare mortality and costs between the two cohorts. RESULTS: A total of 155,466 postmenopausal women in the database met the inclusion criteria for the fracture case cohort, including 22,791 hip fractures, 72,292 vertebral fractures, 15,621 upper end humerus (closed) fractures, 36,774 wrist fractures, and 7,988 multiple fractures. Analytical results demonstrated that patients experiencing osteoporotic fractures were at considerable excess risk of death and incurred substantially higher treatment costs, notably for hip fractures. Furthermore, results also revealed that the risk of mortality increased with advancing age across the spectrum of fracture sites. CONCLUSIONS: The present study confirmed an excess mortality and higher direct medical costs associated with osteoporotic fractures. Moreover, hip fractures constituted the most severe and expensive complication of osteoporosis among fracture types.

Co-existence of histopathological features is characteristic in drug reaction with eosinophilia and systemic symptoms and correlates with high grades of cutaneous abnormalities.

BACKGROUND: Only few studies had investigated the histopathological presentations of drug reaction with eosinophilia with systemic symptoms (DRESS). The results of these studies were diverse and not conclusive. A characteristic histopathological feature is still lacking. OBJECTIVE: We tempted to identify characteristic histopathological features in DRESS and to correlate them with clinical presentations. METHODS: We retrospectively collected data from patients treated from 1998 through 2015. Available skin specimens from probable or definite cases according to the RegiSCAR criteria were analysed for histopathological patterns, which were then compared with the patients' clinical presentations. Chi-squared test was used for comparisons, while Bonferroni correction was applied if multiple comparison tests were encountered. RESULTS: Fifty-six patients with an average age of 52 years were identified, including 22 definite cases. The single most common histopathological pattern was interface dermatitis (75%). The co-existence of two or more patterns in a skin specimen was common (62.5%). In such cases, the co-existence of three patterns (the eczematous pattern, the interface dermatitis pattern and the vascular damage pattern) was most frequently encountered. It exhibited a significantly higher likelihood of being definite cases (P = 0.004) and was significantly associated with high grades of cutaneous abnormalities (P < 0.001). It showed a trend towards having higher grades of haematological abnormalities in patients with co-existence of three patterns (P = 0.04). In addition, patients with the co-existence of three patterns tended to have a higher rate of reactivation of human herpesvirus-6 than those with other patterns but not statistically significant (P = 0.052). CONCLUSION: The co-existence of three histopathological patterns in a skin specimen is characteristic in DRESS and shows a significant association with clinical severity.

Developing immunological methods for detecting Macrobrachium rosenbergii nodavirus and extra small virus using a recombinant protein preparation.

Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) have been identified as the causative agents for white tail disease (WTD) of M. rosenbergii. In this study, the gene sequences encoding MrNV and XSV capsid proteins were separately ligated into the pGEX-4T-3 expression vector and transformed into Escherichia coli. After induction, glutathione-S-transferase (GST)-tagged MrNV and XSV fusion proteins were obtained with molecular masses of 68 and 43 kDa, respectively. Specific polyclonal antibodies for MrNV and XSV against viral recombinant proteins and infected prawn tissues were verified using Western blotting. According to immunodot blot assay results, the detection sensitivities of antibodies were approximately 5 ng µL(-1) for both recombinant proteins GST-MrNV and GST-XSV. In additional, MrNV and XSV were detected at dilution levels of 1:2560 and 1:640 in the infected prawn tissues, respectively. No cross-reactions with white spot syndrome virus or grouper nervous necrosis virus were observed using immunodot blot assays. MrNV and XSV in infected muscle tissues were detected using immunohistochemistry. Although the detection limit of the immunodot blot assay was lower than that of nested reverse transcription polymerase chain reaction, these polyclonal antibodies can be useful for confirming MrNV and XSV infections in field tests.

Human herpes virus reactivations and dynamic cytokine profiles in patients with cutaneous adverse drug reactions --a prospective comparative study.

BACKGROUND: Sequential human herpes virus (HHV) reactivation is well known in drug reaction with eosinophilia and systemic symptom (DRESS), but such a phenomenon has seldom studied in other types of cutaneous adverse drug reactions (cADRs). Moreover, the association between viral reactivations and cytokine or chemokine changes is largely unknown. We aimed to evaluate the viral reactivation rates of HHV-6, HHV-7, Epstein-Barr virus (EBV), and cytomegalovirus (CMV) in different cADRs and their impacts on clinical prognosis. Cytokine and chemokine changes with viral reactivations were also examined. METHODS: A prospective study was conducted to monitor the viral statuses of patients with different cADRs by polymerase chain reaction and serum-specific antibody titers. Changes in plasma cytokine and chemokine levels were also evaluated by sequential blood samples. RESULTS: Among the various cADRs, HHV-6 reactivation was only observed in DRESS, but EBV and CMV could be detected in other cADRs. Many proinflammatory cytokines and chemokines, including interleukin (IL)-1ß, IL-2, IL-6, interferon-γ, tumor necrosis factor-α, were significantly lower in DRESS patients with HHV-6 reactivation when compared to those without HHV-6 reactivation. In addition, these mediators were significantly lower before and during HHV-6 reactivation, compared to cytokine levels after HHV-6 reactivation in the same patient. CONCLUSION: HHV-6 reactivation was only observed in DRESS patients, not in any other cADR. In DRESS patients, some proinflammatory cytokines were significantly lower before or during HHV-6 reactivation.

Trends in the epidemiology, diagnosed age and mortality rate of haemophiliacs in Taiwan: a population-based study, 1997-2009.

Many studies on epidemiology and mortality in haemophiliacs have been published in Western countries. However, few have been conducted in Asian countries. The purpose of our study was to investigate the nationwide epidemiology and mortality of haemophiliacs in Taiwan. Population-based data from the National Health Insurance Research Database between 1997 and 2009 were analysed using SAS version 9.3. The annual prevalence of haemophilia A (HA) and haemophilia B (HB) increased steadily to 7.30 and 1.34 cases per 100,000 males, respectively, in 2009. The annual crude incidence of HA and HB averaged 8.73 and 1.73 per 100,000 male births respectively. During the study period, the proportion of paediatric haemophiliacs decreased from 41.5% to 28.2% and the proportion of geriatric haemophiliacs increased from 2.5% to 5.7%. Among 493 newly diagnosed cases, the peak diagnostic ages were before 3 and between ages 10 and 40. Of the 76 cases of mortality, most patients died between the ages of 18 and 60. However, an increase in the age of mortality was noted after 2005 (P = 0.033). The overall standardized crude death rate of haemophiliacs was 10.2 per 1000 people, and the standard mortality ratio was 1.98. The annual prevalence of human immunodeficiency virus infection in haemophiliacs grossly declined from 1998 to 2009, with an average of 32.2 per 1000 haemophiliacs. This was a rare population-based study on the epidemiology and mortality of haemophilia in a Chinese population and Asian countries. The 13-year trends showed advances in haemophilia care in Taiwan.

Capsular serotypes and multilocus sequence types of bacteremic Klebsiella pneumoniae isolates associated with different types of infections.

We investigated the epidemiology of different serotypes of Klebsiella pneumoniae isolates causing bacteremic liver abscess (LA) using multilocus sequence typing (MLST). MLST and molecular typing were performed for 41 K1 (19 LA), 37 K2 (5 LA), and 33 non-K1/K2 (6 LA) isolates that were derived from a previous one-year K. pneumoniae bacteremia cohort. Capsular serotypes and rmpA of these isolates were determined by polymerase chain reaction (PCR) methods. Among the 41 K1 isolates, 39 were ST23 and the remaining two isolates were ST23 single-locus variant. There were 11 STs among K2 isolates. ST65 was the most common (n = 10), followed by ST86, ST373, and ST375. Only ST65 (n = 3), ST373 (n = 1), and ST375 (n = 1) caused LA, and ST65 was a three-locus variant of ST23. For non-K1/K2 isolates, the ST types varied widely. ST218 (K57) was the most common type (n = 6, 18 %), and it was a single-locus variant of ST23 and caused two cases of LA. The existences of rmpA among serotypes varied (100 % for K1, 89 % for K2, and 55 % for non-K1/K2). For isolates causing LA, all of them were positive for rmpA. For non-K1/K2 isolates causing infections other than LA, the positivity of rmpA ranged from 0 % (biliary tree infection) to 67 % (pneumonia). In this one-year cohort, all K1 isolates were ST23 or its single-locus variants, but the composition of ST types among K2 isolates was quite variable. ST23 and its one- (ST1005 and ST218) and three-locus (ST65) variants comprised 80 % of isolates causing LA.

The estrogen receptor as a mediator of the pathological actions of cholesterol in breast cancer.

Despite increased survivorship among patients, breast cancer remains the most common cancer among women and is the second leading cause of cancer death in women. The magnitude of this problem provides a strong impetus for new chemopreventative strategies and/or lifestyle changes that reduce cancer incidence. It is of significance, therefore, that several studies positively correlate obesity to the development of breast cancer. Importantly, obesity is also highly associated with elevated cholesterol, and cholesterol itself is a risk factor for breast cancer. Furthermore, patients taking statins demonstrate a lower breast cancer incidence and decreased recurrence. The recent observation that 27-hydroxycholesterol (27HC) is produced in a stoichiometric manner from cholesterol, together with our recent demonstration that it exerts partial agonist activity on both the estrogen and liver X receptors, suggested a potential mechanistic link between hyper-cholesterolemia and breast cancer incidence. Using genetic and pharmacological approaches, we have recently shown that elevation of circulating 27HC significantly increases tumor growth and metastasis in murine models of breast cancer. Further, we have demonstrated in appropriate animal models that the impact of high-fat diet on tumor pathogenesis can be mitigated by statins or by small molecule inhibitors of CYP27A1. These findings suggest that pharmacological or dietary modifications that lower total cholesterol, and by inference 27HC, are likely to reduce the impact of obesity/metabolic syndrome on breast cancer incidence.

An unexpected route for otolaryngology bacterial contamination with a Venturi atomizer.

BACKGROUND: The Venturi-principle atomizer is a commonly used device in otolaryngology practices. The purpose of this study is to evaluate the possible route of bacterial contamination from the nasal vestibule to the atomizer tip through the jet airflow created during the use of the Venturi atomizer. METHODS: Thirty nostrils from 15 enrolled volunteers were tested. The aerosols generated by spraying sterilized saline into the nostrils were collected using a specially made aerosol-collecting nozzle cap. The collected samples were sent for bacterial culture, and nasal vestibular swab cultures were performed for comparison. RESULTS: In the aerosol-exposed group, 18 out of 30 samples (60%) were positive for bacterial growth, confirming the bacterial contamination from the nasal vestibule to the atomizer tip through the reverse jet airflow. The bacteria species in 8 of the 18 positive samples were identical to those from the nasal swab culture results from the same nostril. CONCLUSION: In ordinary otolaryngology practices, there are significant risks for bacterial contamination from the nasal vestibule to the tip of the Venturi atomizer even without direct contact. Clinicians must be more aware of this pattern of contamination, which has not been reported in the existing literature.

Accumulation of heavy metals in leaf vegetables from agricultural soils and associated potential health risks in the Pearl River Delta, South China.

This study investigated the extent of heavy metal accumulation in leaf vegetables and associated potential health risks in agricultural areas of the Pearl River Delta (PRD), South China. Total concentrations of mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr) and arsenic (As) were determined in 92 pairs of soil and leaf vegetable (flowering Chinese cabbage, lettuce, pakchoi, Chinese cabbage, loose-leaf lettuce, and Chinese leaf mustard) samples collected from seven agricultural areas (cities). The bioconcentration factors (BCF) of heavy metals from soil to vegetables were estimated, and the potential health risks of heavy metal exposure to the PRD residents through consumption of local leaf vegetables were assessed. Results showed that among the six leaf vegetables, pakchoi had the lowest capacity for heavy metal enrichment, whereas among the five heavy metals, Cd had the highest capacity for transferring from soil into vegetables, with BCF values 30-fold those of Hg and 50-fold those of Cr, Pb and As. Sewage irrigation and fertilization were likely the main sources of heavy metals accumulated in leaf vegetables grown in agricultural areas of the PRD region. Different from previous findings, soil pH had no clear effect on metal accumulation in leaf vegetables. Despite a certain degree of metal enrichment from soil to leaf vegetables, the PRD residents were not exposed to significant health risks associated with consumption of local leaf vegetables. Nevertheless, more attention should be paid to children due to their sensitivity to metal pollutants.