Stability of Lead Immobilized by Apatite in Lead-Containing Rhizosphere Soil of Buckwheat (Fagopyrum esculentum) and Hairy Vetch (Vicia villosa)

This study conducted plant growth experiments using a rhizobox system to understand the growth of buckwheat and hairy vetch as well as the stability of lead immobilized by hydroxyapatite (HAP) in the lead-containing rhizosphere soil. The shoot dry weight of buckwheat did not significantly differ between the lead-containing rhizosphere soil with and without HAP, whereas that of hairy vetch with rhizosphere soil without HAP was reduced. Lead was not accumulated from the rhizosphere soil to the shoots of either plant when HAP was added. The percentage of each lead fraction in sequential extraction was approximately the same through the 3 mm of rhizosphere soils from the root surface and non-planted soil, with and without the addition of HAP. For hairy vetch, the amount of water-soluble lead in the HAP-added rhizosphere soil within 3 mm thickness from the root surface did not increase. However, for buckwheat, the amount of water-soluble lead in the HAP-added rhizosphere soil 1 mm from the root surface increased to the same level as that in the non-planted soil without HAP. Our results suggest that when applying phytostabilization combined with apatite to lead-contaminated soil, the plant that cannot re-mobilize lead should be selected.     

Speciation and Vertical Distribution of Lead and Lead Shot in Soil at a Recreational Firing Range

In this study, the speciation, vertical distribution and soil particle size fractions of lead in soil samples at a recreational firing range was determined. This study was performed to gain a better understanding of how lead shot breaks down at ranges. Both the chemical form of lead and the types of soil particles with which lead is associated are important for understanding not only the mobility and persistence, but also the human and ecological impact of lead at these ranges. Lead as shot gun pellets was found to be the dominant form of lead in soil samples. The highest levels were measured in surface samples located in the “fall zone” of the range. Results indicate shot to be relatively absent below surficial samples. Lead concentrations in soil decreased markedly across a 0–6″ depth profile. Lead carbonates were the dominant non-shot form of lead present at all depths. Water-soluble lead species made up a minor fraction of the non-shot lead present in the samples. Based on soil particle sizes measured, highest concentrations of lead were measured in soil particles passing a 0.075 mm sieve.     

Reconstruction of the Terminal of an Abandoned Fractured Unipolar Coronary Sinus Lead: a Feasible Solution to Restore Effective Cardiac Resynchronization Therapy

Complications related to coronary sinus lead are not infrequent in recipients of cardiac resynchronization devices. We describe the case of a patient with a biventricular implantable cardioverter defibrillator with persistent phrenic nerve stimulation, previous coronary sinus lead fracture, and severe left subclavian vein stenosis. The reimplantation of a new coronary sinus lead on the left side, ipsilateral to the original implant, was unsuccessful. In order to avoid more complex and risky procedures, we performed the repair of the fractured abandoned lead with the reconstruction of the unipolar lead terminal. Effective biventricular pacing was obtained with satisfactory electrical parameters and it was maintained at twelve months follow-up.     

Phytoremediation of Wastewater Containing Lead (Pb) in Pilot Reed Bed Using Scirpus Grossus

Phytoremediation is a technology to clean the environment from heavy metals contamination. The objectives of this study are to threat Pb contaminated wastewater by using phytoremediation technology and to determine if the plant can be mention as hyperaccumulator. Fifty plants of Scirpus grossus were grown in sand medium and 600 L spiked water in various Pb concentration (10, 30 and 50 mg/L) was exposed. The experiment was conducted with single exposure method, sampling time on day-1, day-14, day-28, day-42, day-70, and day-98. The analysis of Pb concentration in water, sand medium and inside the plant tissue was conducted by ICP-OES. Water samples were filtered and Pb concentration were directly analyzed, Pb in sand samples were extracted by EDTA method before analyzed, and Pb in plant tissues were extracted by wet digestion method and analyzed. The results showed that on day-28, Pb concentration in water decreased 100%, 99.9%, 99.7%, and the highest Pb uptake by plant were 1343, 4909, 3236 mg/kg for the treatment of 10, 30, and 50 mg/L respectively. The highest BC and TF were 485,261 on day-42 and 2.5295 on day-70 of treatment 30 mg/L, it can be mentioned that Scirpus grossus is a hyperaccumulator.     

On the kinetics of lead in the human body

Summary A compartment model is derived for the kinetics of lead in the human body. The parameters are estimated from field data. Numerical solutions of the equations are obtained. They are used to discuss recent theories on lead intake, in particular from the atmosphere.     

心电图信号放大和记录中50Hz干扰滤波的新技术——符合滤波

介绍一种用硬、软件系统实现的滤波器,它能实时滤除ECG信号中50Hz及其高次谐波的干扰,该技术称为符合滤波。在信号处理过程中,当干扰发生变化时滤波器能跟踪这种变化,保持滤波器性能不变。     

Removal of soluble Cu and Pb by the automatic drip coffee brewing process: Application to risk assessment

Three commercial brands of coffee were examined for sorption of Cu and Pb. We kept experimental conditions close to those in ordinary situations by using an automatic drip coffee maker. One‐liter increments of de‐ionized water spiked with increasing amounts of Cu and Pb were used to make pots of coffee. Influent (water) metal concentration was then compared with effluent (coffee) metal concentration. We kept influent metal concentrations in ranges that might be expected due to contamination from storage tanks and pipes in municipal water delivery systems (0.1 to 5.0 mg/L). The coffee brewing process removed 78 to 90% of both Cu and Pb from influent water. We ran experiments by varying coffee strength (function of bed depth) and varying brewed coffee volume (function of bed depth and water volume) . Most of the metal that goes through the coffee bed does so in the early stages of the brewing process before the coffee bed is wetted. The main factor influencing removal of soluble metal by coffee is contact time with the wetted coffee bed. Therefore, the strength and/or volume of coffee brewed play a critical role in metal removal. Preliminary work with steeping teabags in metal spiked water showed little to no reduction in the soluble Cu and Pb concentration. Results of this study are important for risk assessment model formulations. Daily human exposure to Cu and Pb from municipal water systems may be grossly overestimated if a large proportion of tapwater ingestion by an individual is filtered through coffee.     

HEAVY METALS AND MARINE PHYTOPLANKTON: CORRELATION OF TOXICITY AND SULFHYDRYL-BINDING1,2

In a study of sublethal effects of metals on growth of the marine diatom Asterionella japonica Cleve, the relative toxicities of Hg, Cu, Zn, Pb, Cd, and Mn are shown to be correlated (r = 0.961) with the solubility products of the corresponding metal sulfides. The results, together with findings elsewhere, suggest a common action for these heavy metals, with toxicity deriving from metal binding to sulfhydryl-containing compounds in the cell.