Online measurement of tetraethyllead in aqueous samples utilizing monolith-based magnetism-enhanced in-tube solid phase microextraction coupled with chromatographic analysis.

A new procedure that utilizing a preconcentration system based on magnetism-enhanced in-tube solid phase microextraction (ME/IT-SPME) and detection by HPLC with diode array detector (DAD) after liquid desorption from the microextraction column has been developed for the online measurement of tetraethyllead (TEL) in various aqueous samples. In this connection, according to the chemical features of TEL, porous monolith mingled with Fe3O4 nanoparticles were designed and synthesized in a silica capillary, and used as the microextraction column of ME/IT-SPME. To favor the implement of variable magnetic fields during extraction procedure, the as-prepared microextraction column was twined a magnetic coil. Results revealed that the exertion of magnetic field during the adsorption and eluting procedures assisted the extraction of TEL with an enhancement by 52% in extraction efficiency. Under the most beneficial conditions, the developed ME/IT-SPME was online hyphenated with HPLC/DAD to measure trace TEL in various aqueous samples. The limit of detection was 0.082 µg/L and the RSDs for precision were in the range of 6.3-8.5%. The recoveries with low, medium and high fortified levels varied from 80.6% to 95.0% with good repeatability. To the best of knowledge, this is the first study that using IT-SPME to extract TEL and then online quantification with HPLC/DAD.

Global decrease in blood lead concentrations due to the removal of leaded gasoline.

Lead (Pb) is a chemical element with extreme toxicity that is classified as one of the ten chemicals of most significant concern to human health. The main problem involving Pb is its use as a fuel additive (tetraethyllead - TEL) at a global level, which raised the atmospheric Pb concentrations. It is estimated that between 80 and 90% of the atmospheric Pb in large cities came from the use of TEL, and as a consequence, it was also the main source responsible for human exposure to the element. Therefore, this work aimed to evaluate, through a systematic review, the blood concentrations of Pb in scientific articles published in the first two decades of the 2000s to compare the global and regional trends of each continent over time. Our data show the importance of removing TEL in decreasing human exposure to Pb worldwide. We observed exponentially decreasing blood Pb concentrations over the years after additive removal on all continents, resulting in a global trend which TEL's use was the major process governing human exposure worldwide. In addition, the results also showed that, despite the removal of Pb additives lowering levels of human blood Pb, the general population remains exposed to the element through exogenous and endogenous sources. The exhaust Pb particles were deposited into the environment in proportion to the traffic flows, and the legacy of Pb in the environment requires novel primary prevention remedy to curtail exposure.

Could Lifetime Lead Exposure Play a Role in Limbic-predominant Age-related TDP-43 Encephalopathy (LATE)?

Limbic-predominant Age-related TDP-43 Encephalopathy (LATE) is a disease in which the clinical presentation mimics that of Alzheimer's disease. TDP-43 proteinopathy associated with LATE has been identified in more than 20% of autopsies of community-dwelling adults over the age of 80. It is believed to contribute significantly toward tau-negative dementia. Heavy metals such as lead has also been linked to TDP-43 proteinopathy. In particular, lead triggers TDP-43 accumulation and disrupts TDP-43 homeostasis. However, the specific relationship between LATE and lead remains unknown. Before leaded gasoline was phased out during the 1970s and 1980s, average blood lead levels were 15 times what they are today. Thus, each successive birth cohort entering old age has had less cumulative lifeime exposure to lead. Lifetime exposure can be tracked in the tibia bone, where the half-life of lead is many decades. We hypothesize that lead plays a role in the development of LATE. There are two ways to explore the validity of this hypothesis. Generational differences in lead exposure should result in a steady decline in the prevalence of LATE among older adults. We propose the use of tibia bone lead levels be examined in conjunction with brain autopsies from different birth cohorts to examine the link between lead exposure and LATE prevalence, holding age constant. Furthermore, individuals with genetic polymorphisms that confer a greater lead absorption phenotype should display a higher degree of TDP-43 accumulation in autopsies. The results of such studies could provide insight into gene by environment interactions relevant to the development of LATE.

Dynamic Geochemistry of Tetraethyl Lead Dust during the 20th Century: Getting the Lead In, Out, and Translational Beyond.

This commentary provides a brief overview of policy decisions that permitted getting tetraethyl lead (TEL) into petrol; global geochemical lead-dust deposition evidence; 1975 catalytic converter requirements; concern about habitability of cities; a personal perspective on legacy lead research that accelerated getting TEL out of petrol; and translational beyond, including New Orleans pre- vs. post-Hurricane Katrina observations about legacy lead interventions that effectively improve urban children’s health outcomes.

Is tetraethyl lead poison affecting contemporary indigenous suicides in Ontario, Canada?

Prior to the mid-1980s, suicide in Indigenous population in Northwestern Ontario, Canada, was rare, occurring at rates of 1-2 per year among over 20 communities. By the early 1990s, the completed suicide rates in the same communities were among the highest in the world. Prior to the outbreak of the suicide epidemic, sniffing of gasoline containing tetraethyl was common in many communities. Existing literature confirms that tetraethyl lead poisoning is associated with alterations to the amyloid-ß protein precursor and amyloid-ß as well as the 5-HT-1B receptor. The presence of this risk factor within the population warrants further inquiry.

Nature and extent of metal-contaminated soils in urban environments (keynote talk).

Research on the nature and extent of metal-contaminated soil began with an urban garden study in Baltimore, MD (USA). Largest quantities of soil metals were clustered in the inner city with lesser amounts scattered throughout metropolitan Baltimore. The probability values of metal clustering varied from P value 10(-15)-10(-23) depending on element. The inner-city clustering of lead (Pb) could not be explained by Pb-based paint alone. A major Pb source was tetraethyl lead (TEL), developed as an anti-knock agent for use in vehicle fuel, thereby making highway traffic flow a toxic substance delivery system in cities. Further study in Minneapolis and St. Paul confirmed the clustering of inner-city soil metals, especially Pb. Based on the evidence, the Minnesota State Legislature petitioned Congress to curtail Pb additives resulting in the rapid phasedown of TEL on January 1, 1986, 10 years ahead of the EPA scheduled ban. Further research in New Orleans, Louisiana (NOLA), verified the link between soil Pb, blood Pb, morbidity, and societal health. Although Pb is a known cause of clinical impairment, there is no known effective medical intervention for reducing children's blood Pb exposure. Ingestion and inhalation are routes of exposure requiring prevention, and soil is a reservoir of Pb. Children's blood Pb exposure observed in pre-Hurricane Katrina (August 29, 2005) NOLA underwent substantial decreases 10 years post-Katrina due to many factors including input of low Pb sediment residues by the storm surge and the introduction of low Pb landscaping materials from outside of the city. Investigation on the topic is ongoing.

Speciation analysis of lead in marine animals by using capillary electrophoresis couple online with inductively coupled plasma mass spectrometry.

We herein reported a environment-friendly microwave-assisted extraction used to extract trace lead compounds from marine animals and a ultrasensitive method for the analysis of Pb²âº, trimethyl lead chloride (TML) and triethyl lead chloride (TEL) by using CE-ICP-MS. The extraction method is simple and has a high extracting efficiency. It can be used to completely extract both inorganic lead and organolead in marine animal samples without altering its species. The analytical method has a detection limit as low as 0.012-0.084 ng Pb/mL for Pb²âº, TML, and TEL, and can be used to determine ultratrace Pb²âº, TML, and TEL in marine animals directly without any preconcentration. With the help of above methods, we have successfully determined Pb²âº, TML, and TEL in clam and oyster tissue within 20 min with a RSD (n = 6) < 5% and a recovery of 91-104%. Our results showed that Pb²âº was the main species of lead in clam and oyster, and organolead (TML) was only found in oyster. The proposed method provides a realistic approach for the accurate evaluation of lead pollution in seafood.

Effect of trimethyllead chloride on slowly activating (SV) channels in red beet (Beta vulgaris L.) taproots.

The patch-clamp technique was used to examine the effect of trimethyllead chloride (Met(3)PbCl) on SV channel activity in red beet (Beta vulgaris L.) taproot vacuoles. It was found that in the control bath the macroscopic currents showed the typical slow activation and a strong outward rectification of the steady-state currents. An addition of Met(3)PbCl to the bath solution blocked, in a concentration-dependent manner, SV currents in red beet vacuoles. The time constant τ increased several times in the presence of 100 µM trimethyllead chloride at all voltages tested. When single channel properties were analyzed, only little channel activity could be recorded in the presence of 100 µM Met(3)PbCl. Trimethyllead chloride decreased significantly (by about one order of magnitude) the open probability of single channels. The recordings of single channel activity obtained in the presence and absence of Met(3)PbCl showed that organolead only slightly (by ca. 10%) decreased the unitary conductance of single channels. It was also found that Met(3)PbCl diminished significantly the number of SV channel openings, whereas it did not change the opening times of the channels. Taken together, these results suggest that Met(3)PbCl binding site is located outside the channel selectivity filter.

Alkyllead compounds and their environmental toxicology.

Alkyllead compounds are man-made compounds in which a carbon atom of one or more organic molecules is bound to a lead atom. Tetraethyllead and tetramethyllead are the most common alkyllead compounds that were used primarily as gasoline additives for many years. Consequently, auto emissions have accounted for a major part of lead environmental pollution. Alkyllead compounds can readily enter living organisms as they are well absorbed via all major routes of entry. Because of their lipid solubility, the alkylleads can also readily cross the blood-brain barrier. The toxicokinetic information on organic lead can be used as biomarkers of exposure for monitoring exposed individuals. The organic alkyllead compounds are more toxic than the inorganic forms of lead. Neurotoxicity is the predominant effect of lead (both for organic and inorganic forms), although lead affects almost every organ of the body. The use of alkyllead compounds has declined over the last 20 years, due to the worldwide effort to eliminate the use of leaded gasoline. This achievement can be viewed as a great accomplishment of public health preventive measures.

Superstatistics analysis of the ion current distribution function: Met3PbCl influence study.

A novel analysis of ion current time series is proposed. It is shown that higher (second, third and fourth) statistical moments of the ion current probability distribution function (PDF) can yield new information about ion channel properties. The method is illustrated on a two-state model where the PDF of the compound states are given by normal distributions. The proposed method was applied to the analysis of the SV cation channels of vacuolar membrane of Beta vulgaris and the influence of trimethyllead chloride (Met(3)PbCl) on the ion current probability distribution. Ion currents were measured by patch-clamp technique. It was shown that Met(3)PbCl influences the variance of the open-state ion current but does not alter the PDF of the closed-state ion current. Incorporation of higher statistical moments into the standard investigation of ion channel properties is proposed.

Severe neurotoxicity following ingestion of tetraethyl lead.

Organic lead compounds are potent neurotoxins which can result in death even from small exposures. Traditionally, these compounds are found in fuel stabilizers, anti-knock agents, and leaded gasoline. Cases of acute organic lead intoxication have not been reported for several decades. We report a case of a 13-year-old Iraqi male who unintentionally ingested a fuel stabilizer containing 80-90% tetraethyl lead, managed at our combat support hospital. The patient developed severe neurologic symptoms including agitation, hallucinations, weakness, and tremor. These symptoms were refractory to escalating doses of benzodiazepines and ultimately required endotracheal intubation and a propofol infusion. Adjunctive therapies included chelation, baclofen, and nutrition provided through a gastrostomy tube. The patient slowly recovered and was discharged in a wheelchair 20 days after ingestion, still requiring tube feeding. Follow-up at 62 days post-ingestion revealed near-resolution of symptoms with residual slurred speech and slight limp. This case highlights the profound neurotoxic manifestations of acute organic lead compounds.

Exposure to 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin and tetraethyl lead affects lung mitochondria bioenergetics.

Environmental pollutants such as TCDD and tetraethyl lead are extremely toxic and related with pulmonary disease development. Lung mitochondria are primary cellular targets for dioxins exposure-induced toxicity. TCDD showed a delay in the repolarization after a phosphorylative cycle and a decrease on state 3 respiration, suggesting alterations at the phosphorylative system level. The ATPase activity showed no differences between control and lung mitochondria incubated with TCDD, implying alterations in other components of the phosphorylative system. Tetraethyl lead also showed a delay in the repolarization after a phosphorylative cycle and a decrease on RCR. These data suggest that lung mitochondria incubated with TCDD and tetraethyl lead showed impaired mitochondrial function, reflecting the loss of oxidative phosphorylation capacity.

Development of a methodology for the simultaneous determination of inorganic and organolead compounds using supercritical fluid extraction followed by gas chromatography-mass spectrometry and its application to environmental matrices.

A method for the extraction of triethyl lead (TEL(+)), trimethyl lead (TML(+)), and Pb(2+) from sand was developed using supercritical modified CO(2)-CH(3)OH extraction and in situ complexation with sodium diethyldithiocarbamate (NaDDTC) using a 2(5) factorial exploratory design is described. The screened variables were (i) pressure (69-193 bar), (ii) temperature (40-150 degrees C), (iii) ligand amount (0-100 mg), (iv) methanol volume (0.0-0.5 mL) and (v) static time (0-45 min). The optimum extraction conditions found were as follow: pressure, 193 bar; temperature, 40 degrees C; amount of NaDDTC, 100 mg; methanol volume, 0.5 mL; static time 45 min; and CO(2) flow rate, 1 mL min(-1). Under these conditions the following recoveries were obtained (TML(+) 97+/-2%, TEL(+) 70+/-5%, and Pb(2+) 100+/-4%). The presence of NaDDTC is not necessary for the extraction of TML(+) and TEL(+), but it is a very significative parameter for Pb(2+). A second experimental design 2(2)+star for temperature and pressure was realized, but the results were not better than those of the first model. SFE extract derivatization was achieved with pentylmagnesium bromide, and target analyte determination was carried out by gas chromatography-mass spectrometry. Detection limits in the full-scan mode were 4, 10, and 39 pg as lead for TMPeL, TEPeL and PbPe(4), respectively. The method was validated with urban dust containing TML(+) (CRM 605. Pb 7.9 +/-1.2 microg kg(-1)) and river sediment containing inorganic lead (GBW08301. Pb 79.0+/-12.0 mg kg(-1)) as reference materials. The proposed method was applied to lead analysis in sand collected from an oil-polluted beach in Chile.

Feasibility study for the remediation of groundwater contaminated by organolead compounds.

The aim of this research was to assess the effectiveness of chemical oxidation, Advanced Oxidation Processes (AOPs) and adsorption on granular activated carbon (GAC) for the ex situ remediation of a groundwater contaminated by organolead compounds, including tetraethyl lead (TEL), triethyl lead (TREL) and diethyl lead (DEL). The groundwater of concern was collected from the site of a former tetraalkyllead producing company in Trento (Italy), and showed an average total organic lead (TOL) content about 95.1 microg/L (TEL 0.5 microg/L, TREL 86.4 microg/L, DEL 8.3 microg/L). The main target of the study was to find out which method was more effective in reducing the pollutant content. For this purpose, several laboratory tests were performed, including chemical oxidation tests with different reactants (hydrogen peroxide, modified Fenton's reagent, potassium permanganate, activated potassium persulfate, oxygen and combinations of potassium permanganate and modified Fenton's reagent), AOPs with ozone, UV radiation and hydrogen peroxide and filtration on granular activated carbon. A combination of chemical and physical treatments was also tested, with GAC filtration followed by chemical oxidation. According to the results achieved, the treatments which showed the best remediation performances were: chemical oxidation with modified Fenton's reagent, AOPs with hydrogen peroxide and ozone (perozone), AOPs with hydrogen peroxide and UV radiation, and the combined treatment with activated carbon filtration followed by chemical oxidation with perozone. All these treatments showed a 90% TOL removal, with excellent removals of both TEL and TREL, and final DEL concentrations below 5 microg/L.

Indicadores biológicos para la valoración de la exposición humana a compuestos químicos industriales : Compuestos alquílicos de plomo

Traducción de la obra en inglés \"Biological indicators for the assessment of human exposure to industrial chemicals\" (EUR 10704 EN) publicada por la Oficina para las Publicaciones Oficiales de las Comunidades Europeas. Contiene: propiedades químicas y físicas de los compuestos alquílicos de plomo, efectos en los humanos, metabolismo, indicadores biológicos...

Trialkyllead compounds induce the opening of the MTP pore in rat liver mitochondria.

The interactions of the tributyl, triethyl and trimethyllead compounds with energized mitochondria have been investigated in this paper. It has been shown that the (alkyl)(3)Pb-Cl compounds induce swelling in mitochondria suspended in a sucrose medium. The phenomenon is more marked the higher the lipophilicity and occurs in the following order: (Bu)(3)Pb>(Et)(3)Pb>(Me)(3)Pb. As swelling is inhibited by cyclosporine, this suggests that the swelling is due to the opening of a trans-membrane pore (MTP pore) in the mitochondria. As this pore can be responsible for the inhibition of the ATP synthesis, and, consequently for cell death, the opening of the pore could be one of the reasons for the toxicity of the (alkyl)(3)Pb-X compounds.

Effects of lead on the adult brain: a 15-year exploration.

BACKGROUND: Historically, there has been minimal concern about the effect of adult lead exposure on the brain. Evidence from recent longitudinal studies raise concerns about the long-term effects of past exposure. METHODS: We initiated three independent longitudinal studies to determine whether cumulative lead exposure was associated with persistent or progressive brain effects. The studies include 1,109 former U.S. organolead manufacturing workers, 803 current and former inorganic lead workers in Korea, and 1,140 50- to 70-year-old Baltimore residents with environmental lead exposure. The organolead workers had past exposure to inorganic and tetraethyl lead (TEL); in the other two studies, exposure was to inorganic lead. In each of these studies, we measured blood lead and tibia and patella lead by 109Cd K-shell-induced X-ray fluorescence. RESULTS: Higher tibia lead was consistently associated with poorer measures of cognitive function. Longitudinal analysis of the Korean and organolead cohort indicate that the effect of lead is persistent. Moreover, MRI data on organolead workers indicates a possible progressive effect from past exposure; higher tibia lead was associated with lower brain volume. The latter study indicates that a difference in tibia lead equivalent to about one-sixth of the overall range was associated with a mean difference in these cognitive tests that was equivalent, on average, to what was observed for a five-year age difference. CONCLUSIONS: Our data suggest that a significant proportion of what is considered to be "normal" age-related cognitive decline may, in fact, be due to past exposure to neurotoxicants such as lead.

Emissions of organo-metal compounds via the leachate and gas pathway from two differently pre-treated municipal waste materials -- A landfill reactor study.

Due to their broad industrial production and use as PVC-stabilisers, agro-chemicals and anti-fouling agents, organo-metal compounds are widely distributed throughout the terrestrial and marine biogeosphere. Here, we focused on the emission dynamics of various organo-metal compounds (e.g., di,- tri-, tetra-methyl tin, di-methyl mercury, tetra-methyl lead) from two different kinds of pre-treated mass waste, namely mechanically-biologically pre-treated municipal solid waste (MBP MSW) and municipal waste incineration ash (MWIA). In landfill simulation reactors, the emission of the organo-metal compounds via the leachate and gas pathway was observed over a period of 5 months simulating different environmental conditions (anaerobic with underlying soil layer/aerated/anaerobic). Both waste materials differ significantly in their initial amounts of organo-metal compounds and their environmental behaviour with regard to the accumulation and depletion rates within the solid material during incubation. For tri-methyl tin, the highest release rates in leachates were found in the incineration ash treatments, where anaerobic conditions in combination with underlying soil material significantly promoted its formation. Concerning the gas pathway, anaerobic conditions considerably favour the emission of organo-metal compounds (tetra-methyl tin, di-methyl mercury, tetra-methyl lead) in both the MBP material and especially in the incineration ash.