Characterization of lead-recycling facility emissions at various workplaces : major insights for sanitary risks assessment

Most available studies on lead smelter emissions deal with the environmental impact of outdoor particles, but only a few focus on air quality at workplaces. The objective of this study is to physically and chemically characterize the Pb-rich particles emitted at different workplaces in a lead recycling plant. A multi-scale characterization was conducted from bulk analysis to the level of individual particles, to assess the particles properties in relation with Pb speciation and availability. Process PM from various origins were sampled and then compared; namely Furnace and Refining PM respectively present in the smelter and at refinery workplaces, Emissions PM present in channeled emissions.These particles first differed by their morphology and size distribution, with finer particles found in emissions. Differences observed in chemical composition could be explained by the industrial processes. All PM contained the same major phases (Pb, PbS, PbO, PbSO4 and PbO·PbSO4) but differed on the nature and amount of minor phases. Due to high content in PM, Pb concentrations in the CaCl2 extractant reached relatively high values (40 mg.L-1). However, the ratios (soluble/total) of CaCl2 exchangeable Pb were relatively low (< 0.02%) in comparison with Cd (up to 18%). These results highlight the interest to assess the soluble fractions of all metals (minor and major) and discuss both total metal concentrations and ratios for risk evaluations. In most cases metal extractability increased with decreasing size of particles, in particular, lead exchangeability was highest for channeled emissions. Such type of study could help in the choice of targeted sanitary protection procedures and for further toxicological investigations. In the present context, particular attention is given to Emissions and Furnace PM. Moreover, exposure to other metals than Pb should be considered. [Authors]

Response-to-comments about: "Is it really the method for carbon dioxide determination in human postmortem cardiac gas samples using Headspace-Gas Chromatography-Mass Spectrometry valid?" from T. Saffaj and B. Ihssane

Saffaj et al. recently criticized our method of monitoring carbon dioxide in human postmortem cardiac gas samples using Headspace-Gas Chromatography-Mass Spectrometry. According to the authors, their demonstration, based on the latest SFSTP guidelines (established after 2007 [1,2]) fitted for the validation of drug monitoring bioanalytical methods, has put in evidence potential errors. However, our validation approach was built using SFSTP guidelines established before 2007 [3-6]. We justify the use of these guidelines because of the post-mortem context of the study (and not clinical) and the gaseous state of the sample (and not solid or liquid). Using these guidelines, our validation remains correct.

Point Mutations in the Monocarboxylate Transporter SLC16A12 Lead to Juvenile and Age-Related Cataract

Purpose: Previously we reported on a premature termination mutation in SLC16A12 that leads to dominant juvenile cataract and renal glucosuria. To assess the mutation rate and genotype-phenotype correlations of SLC16A12 in juvenile or age-related forms of cataract, we performed a mutation screen in cataract patients. Methods: Clinical data of approximately 660 patients were collected, genomic DNA was isolated and analyzed. Exons 3 to 8 including flanking intron sequences of SLC16A12 were PCR amplified and DNA sequence was determined. Selected mutations were tested by cell culture assays, in silico analysis and RT-PCR. Results: We found sequence alterations at a rate of approximately 1/75 patients. None of them was found in 360 control alleles. Alterations affect splice site and regulatory region but most mutations caused an amino acid substitution. The majority of the coding region mutations maps to trans-membrane domains. One mutation located to the 5'UTR. It affects translational efficiency of SLC16A12. In addition, we identified a cataract-predisposing SNP in the non-coding region that causes allele-specific splicing of the 5'UTR region. Conclusions: Altered translational efficiency of the solute carrier SLC16A12 and its allele-specific splicing strongly support a model of challenged homeostasis to cause various forms of cataract. In addition, the pathogenic property of the here reported sequence alterations is supported by the lack of known sequence variations within the coding region of SLC16A12. Due to the relatively high mutation rate, we suggest to include SLC16A12 in diagnostic cataract screening. Generally, our data recommend the assessment of regulatory sequences for diagnostic purposes.

Transcutaneous carbon dioxide tension in newborn infants: reliability and safety of continuous 24-hour measurement at 42 degrees C.

In 58 newborn infants a new iridium oxide sensor was evaluated for transcutaneous carbon dioxide (tcPCO2) monitoring at 42 degrees C with a prolonged fixation time of 24 hours. The correlation of tcPCO2 (y; mm Hg) v PaCO2 (x; mm Hg) for 586 paired values was: y = 4.6 + 1.45x; r = .89; syx = 6.1 mm Hg. The correlation was not influenced by the duration of fixation. The transcutaneous sensor detected hypocapnia (PaCO2 less than 35 mm Hg) in 74% and hypercapnia (PCO2 greater than 45 mm Hg) in 74% of all cases. After 24 hours, calibration shifts were less than 4 mm Hg in 90% of the measuring periods. In 86% of the infants, no skin changes were observed; in 12% of infants, there were transitional skin erythemas and in 2% a blister which disappeared without scarring. In newborn infants with normal BPs, continuous tcPCO2 monitoring at 42 degrees C can be extended for as many as 24 hours without loss of reliability or increased risk for skin burns.

A combined ear sensor for pulse oximetry and carbon dioxide tension monitoring: accuracy in critically ill children.

IMPLICATIONS: A new combined ear sensor was tested for accuracy in 20 critically ill children. It provides noninvasive and continuous monitoring of arterial oxygen saturation, arterial carbon dioxide tension, and pulse rate. The sensor proved to be clinically accurate in the tested range.

Lead acetate toxicity in vitro: Dependence on the cell composition of the cultures.

It is well known that exposure to low doses of lead causes long-lasting neurobehavioural deficits, but the cellular changes underlying these behavioural changes remain to be elucidated. A protective role of glial cells on neurons through lead sequestration by astrocytes has been proposed. The possible modulation of lead neurotoxicity by neuron-glia interactions was examined in three-dimensional cultures of foetal rat telencephalon. Mixed-brain cell cultures or cultures enriched in either neurons or glial cells were treated for 10 days with lead acetate (10(-6) m), a concentration below the limit of cytotoxicity. Intracellular lead content and cell type-specific enzyme activities were determined. It was found that in enriched cultures neurons stored more lead than glial cells, and each cell type alone stored more lead than in co-culture. Moreover, glial cells but not neurons were more affected by lead in enriched culture than in co-culture. These results show that neuron-glia interactions attenuate the cellular lead uptake and the glial susceptibility to lead, but they do not support the idea of a protective role of astrocytes.

In vitro assessment of the pulmonary toxicity and gastric availability of lead-rich particles from a lead recycling plant

Epidemiological studies in urban areas have linked increasing respiratory and cardiovascular pathologies with atmospheric particulate matter (PM) from anthropic activities. However, the biological fate of metal-rich PM industrial emissions in urban areas of developed countries remains understudied. Lead toxicity and bioaccessibility assessments were therefore performed on emissions from a lead recycling plant, using complementary chemical acellular tests and toxicological assays, as a function of PM size (PM(10-2.5), PM(2.5-1) and PM(1)) and origin (furnace, refining and channeled emissions). Process PM displayed differences in metal content, granulometry, and percentage of inhalable fraction as a function of their origin. Lead gastric bioaccessibility was relatively low (maximum 25%) versus previous studies; although, because of high total lead concentrations, significant metal quantities were solubilized in simulated gastrointestinal fluids. Regardless of origin, the finest PM(1) particles induced the most significant pro-inflammatory response in human bronchial epithelial cells. Moreover, this biological response correlated with pro-oxidant potential assay results, suggesting some biological predictive value for acellular tests. Pulmonary effects from lead-rich PM could be driven by thiol complexation with either lead ions or directly on the particulate surface. Finally, health concern of PM was discussed on the basis of pro-inflammatory effects, accellular test results, and PM size distribution.

Transthoracic adrenal biopsy procedure using artificial carbon dioxide pneumothorax as outpatient procedure.

Many routes have been described for percutaneous adrenal gland biopsy. They require either a complex non-axial path or a long hydrodissection or even pass through an organ thereby increasing complications. We describe here an approach using an artificially-induced carbon dioxide (CO2) pneumothorax, performed as an outpatient procedure in a 57-year-old woman. Under local anaesthesia, 200 ml of CO2 was injected in the pleural space through a Veress needle under computed tomography fluoroscopy, to clear the lung parenchyma from the biopsy route. Using this technique, transthoracic adrenal biopsy can be performed under simple local anaesthesia as an safely outpatient procedure.

Carbon and oxygen isotope study of hydrothermal carbonates in the zinc-lead deposits of the San Vicente district, central Peru: A quantitative modeling on mixing processes and CO2 degassing

Carbon and oxygen isotope studies of the host and gangue carbonates of Mississippi Valley-type zinc-lead deposits in the San Vicente District hosted in the Upper Triassic to Lower Jurassic dolostones of the Pucara basin (central Peru) were used to constrain models of the ore formation. A mixing model between an incoming hot saline slightly acidic radiogenic (Pb, Sr) fluid and the native formation water explains the overall isotopic variation (delta(13)C = - 11.5 to + 2.5 parts per thousand relative to PDB and delta(18)O = + 18.0 to + 24.3 parts per thousand relative to SMOW) of the carbonate generations. The dolomites formed during the main ore stage show a narrower range (delta(13)C = - 0.1 to + 1.7 parts per thousand and delta(18)O = + 18.7 to + 23.4 parts per thousand) which is explained by exchange between the mineralizing fluids and the host carbonates combined with changes in temperature and pressure. This model of fluid-rock interaction explains the pervasive alteration of the host dolomite I and precipitation of sphalerite I. The open-space filling hydrothermal white sparry dolomite and the coexisting sphalerite II formed by prolonged fluid-host dolomite interaction and limited CO2 degassing. Late void-filling dolomite III (or calcite) and the associated sphalerite III formed as the consequence of CO2 degassing and concomitant pH increase of a slightly acidic ore fluid. Widespread brecciation is associated to CO2 outgassing. Consequently, pressure variability plays a major role in the ore precipitation during the late hydrothermal events in San Vicente. The presence of native sulfur associated with extremely carbon-light calcites replacing evaporitic sulfates (e.g., delta(13)C = - 11.5 parts per thousand), altered native organic matter and heavier hydrothermal bitumen (from - 27.0 to - 23.0 parts per thousand delta(13)C) points to thermochemical reduction of sulfate and/or thiosulfate. The delta(13)C- and delta(18)O-values of the altered host dolostone and hydrothermal carbonates, and the carbon isotope composition of the associated organic matter show a strong regional homogeneity. These results coupled with the strong mineralogical and petrographic similarities of the different MVT occurrences perhaps reflects the fact that the mineralizing processes were similar in the whole San Vicente belt, suggesting the existence of a common regional mineralizing hydrothermal system with interconnected plumbing.

Transcutaneous carbon dioxide and oxygen tension in newborn infants: reliability of a combined monitor of oxygen tension and carbon dioxide tension.

We evaluated a new combined sensor for monitoring transcutaneous carbon dioxide tension (PtcCO2) and oxygen tension (PtcO2) in 20 critically ill newborn infants. Arterial oxygen tension (PaO2) ranged from 16 to 126 torr and arterial carbon dioxide tension (PaCO2) from 14 to 72 torr. Linear correlation analysis (100 paired values) of PtcO2 versus PaO2 showed an r value of 0.75 with a regression equation of PtcO2 = 8.59 + 0.905 (PaO2), while PtcCO2 versus PaCO2 revealed a correlation coefficient of r = 0.89 with an equation of PtcCO2 = 2.53 + 1.06 (PaCO2). The bias between PaO2 and PtcO2 was -2.8 with a precision of +/- 16.0 torr (range, -87 to +48 torr). The bias between PaCO2 and PtcCO2 was -5.1 with a precision of +/- 7.3 torr (range, -34 to +8 torr). The transcutaneous sensor detected 83% of hypoxia (PaO2 less than 45 torr), 75% of hyperoxia (PaO2 greater than 90 torr), 45% of hypocapnia (PaCO2 less than 35 torr), and 96% of hypercapnia (PaCO2 greater than 45 torr). We conclude that the reliability of the combined transcutaneous PO2 and PCO2 monitor in sick neonates is good for detecting hypercapnia, fair for hypoxia and hyperoxia, but poor for hypocapnia. It is an improvement in that it spares available skin surface and requires less handling, but it appears to be slightly less accurate than the single electrodes.

A low-dose stimulation protocol using highly purified follicle-stimulating hormone can lead to high pregnancy rates in in vitro fertilization patients with polycystic ovaries who are at risk of a high ovarian response to gonadotropins.

OBJECTIVE: To study the benefits of a low-dose stimulation (LDS) protocol with purified urinary follicle-stimulating hormone in patients with polycystic ovaries who have presented previously with a very high ovarian response to a standard hMG stimulation. DESIGN: Cohort study. SETTING: Fertility center in a university hospital. PATIENT(S): Sixty-one patients involved in an IVF/ICSI program from January 1995 to December 1996. INTERVENTION(S): The patients were first stimulated with a standard protocol using hMG and presented with a very high ovarian response. These patients were then stimulated a second time using a low-dose protocol. Cryopreserved embryos were transferred in later artificial or natural cycles until to December 1999. MAIN OUTCOME MEASURE(S): Number of gonadotropin ampules; estradiol level on the day of ovulation induction; follicles, oocytes, and cryopreserved zygotes; fertilization, implantation, and pregnancy rates; and number of ovarian hyperstimulation syndromes (OHSS). RESULT(S): The number of ampules used, the estradiol level reached, and the number of oocytes obtained were significantly lower under the LDS than the standard protocol. High implantation (21.8%) and clinical pregnancy (38.4%) rates were obtained after LDS. The cumulated deliveries per cycle started and per patient were, respectively, 41.6% and 52.5%. Five patients suffered OHSS with the standard protocol, and none with the LDS. CONCLUSION(S): The LDS protocol offers a safe and efficient treatment for patients who present with echographic polycystic ovaries and are at risk of an excessive ovarian response to standard IVF stimulation protocols.

Lead acetate toxicity in vitro: Dependence on the cell composition of the cultures.

It is well known that exposure to low doses of lead causes long-lasting neurobehavioural deficits, but the cellular changes underlying these behavioural changes remain to be elucidated. A protective role of glial cells on neurons through lead sequestration by astrocytes has been proposed. The possible modulation of lead neurotoxicity by neuron-glia interactions was examined in three-dimensional cultures of foetal rat telencephalon. Mixed-brain cell cultures or cultures enriched in either neurons or glial cells were treated for 10 days with lead acetate (10(-6) m), a concentration below the limit of cytotoxicity. Intracellular lead content and cell type-specific enzyme activities were determined. It was found that in enriched cultures neurons stored more lead than glial cells, and each cell type alone stored more lead than in co-culture. Moreover, glial cells but not neurons were more affected by lead in enriched culture than in co-culture. These results show that neuron-glia interactions attenuate the cellular lead uptake and the glial susceptibility to lead, but they do not support the idea of a protective role of astrocytes.