Different Levels Of Lead Research Articles

Effect of applied lead on the growth and accumulation of lead in Indian spinach in three textural groups of soils

Indian spinach (Basella rubra L.) was grown in earthen pots containing soils of three different textures and treated with different levels of lead. The effects of Pb treatments on growth and uptake of Pb were investigated. At the highest dose of Pb ( 50 mg Pb kg-1 soil) leaf, stem and root dry weight of Indian spinach were reduced by 22-34, 11- 43 and 30-47 %, respectively from control in clay loam, sandy clay loam and sandy loam soil, respectively. Lead concentration in leaf, stem and root generally increased with increasing rate of Pb application. The highest Pb concentrations in leaf, stem and root were obtained at 50 mg Pb kg-1 soil treatment and the values were in the ranges from 49.28 to 65.40, 57.72 to 77.51 and 46.69 to 71.78 mg kg-1, respectively. Bioaccumulation coefficients of Pb in leaf, stem and root of Indian spinach were in the ranges of 0.63- 1.94, 0.82-2.21 and 0.37-1.09, respectively. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13377 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):113-124, 2010

Short- and Long-Term Exposure of Lumbriculus variegatus (Oligochaete) to Metal Lead: Ecotoxicological and Behavioral Effects

ABSTRACT Metals are naturally occurring constituents of the environment and although many are essential nutrients for living organisms, at higher concentrations they can be toxic. Some aquatic species can help understand and even predict the impact of those contaminants. Lumbriculus variegatus is a recommended species for use in sediment toxicity tests and is known to have a remarkable ability of segmental regeneration. Short- (10-day) and long-term (28-day) toxicity tests were used to test the effects of a metal on the survival, growth, and behavior of L. variegatus. This work aims to investigate and validate the use of behavior as a new parameter in standard toxicity tests. Worms were exposed to sediments contaminated with different levels of lead and the results indicated a positive relation between lead concentrations and mortality and growth: higher lead concentrations resulted in higher mortalities and strong inhibition of growth. An inhibition of behavior was observed and results suggested that although behavior could not be used in sediment toxicity tests, it proved useful as an addition to short-term tests and helps select sediments. Thus, exposure to sediments contaminated with lead affects the presence of this species in nature, because it interferes with growth and survival.

Temporal changes of polyphenols and enzyme activities in seedlings of Kandelia obovata under lead and manganese stresses

The temporal responses of peroxidase (POD), superoxide dismutase (SOD), total polyphenols (TP), extractable condensed tannins (ECT) to different levels of lead (Pb) or manganese (Mn) stress, as well as the metal accumulation, in seedlings of Kandelia obovata were investigated. Both stress time and stress intensity had significant effects with significant accumulation of Pb and Mn in roots at Day 1. Pb and Mn showed no significant effects on root or leaf TP and ECT at Day 1. Prolonged exposure to metals caused significant drops of root TP and ECT but increased in leaves at Days 7 and 49. POD activities decreased in both roots and leaves at Day 1, while POD and SOD both increased under moderate levels of Pb and Mn at Day 7. The present study showed that antioxidative enzyme activities were more sensitive indicators to Pb or Mn stresses than phenolic compounds.

Relationship of Lead, Mercury, Mirex, Dichlorodiphenyldichloroethylene, Hexachlorobenzene, and Polychlorinated Biphenyls to Timing of Menarche Among Akwesasne Mohawk Girls

Relationship of Lead, Mercury, Mirex, Dichlorodiphenyldichloroethylene, Hexachlorobenzene, and Polychlorinated Biphenyls to Timing of Menarche Among Akwesasne Mohawk Girls

Determination of Lead in Botanicals/Chinese Prepared Medicines by Using Microwave Digestion with Flow Injection–Inductively Coupled Plasma–Mass Spectrometry

A simple, sensitive, and rapid method was developed for the determination of lead in botanicals and Chinese prepared medicines (CPM) by using closed-vessel microwave digestion with flow injection-inductively coupled plasma-mass spectrometry. The limits of detection and quantitation for the method, based on 0.5 g digested sample, were calculated to be 0.10 and 0.61 mg/kg, respectively. A simple approach was proposed for calibration by multiple linear regression (MLR) with 207Pb, 206Pb, and 204Pb for the determination of lead in botanical and CPM samples. The results from calibration by MLR were compared with those obtained by conventional modes using 207Pb and the sum of 207Pb and 206Pb. The results obtained by the different modes of calibration were in good agreement for botanical and CPM samples. The method was found to have good accuracy for the analysis of botanical reference materials. Method precision based on analyses of different types of CPM samples by different analysts on different days for different levels of lead was between 3.0 and 8.0% (relative standard deviation, n = 6). The effect of possible matrix interference caused by nitric acid and the extent of digestion was investigated with the method of standard additions. Significant matrix interference was not observed for the CPM samples analyzed. MLR was used to examine the effect of variation in isotopic abundance, which was found to present no significant problem in the determination of lead in the botanical and CPM samples.

EEECI OF LEAD EXPOSURE ON SOME SELECTED BIOCHEMICAL AND HAEMATOLOGICAL VARIABLES WITH SPECIAL REFERENCE TO REPRODUCTIVE TOXICITY IN FEMALE RABBITS.

The present study was designed to assess the effect of different levels of lead on ovarian activity and to elucidate some biochemical and haematological variables that can be associated with these levels. Immature female New Zealand rabbits were used, divided into four groups, each of six rabbits. Group I and II received low (5.4 mg/kg b. wt.) and high (10.8 mg / kg b.wt.) doses of lead acetate orally, respectively, daily for 5 days/week over a period of 8 weeks. Groups III and IV were kept as control. All groups (except group IV) were treated with 200 1.U pregnant mare serum gonadotrophin (PMSG) I/m, followed by i.m injection of 200 I.U human chorionic gonadotrophin (HCG), 48hrs after commencement of PMSG treatment. The results indicated that injection of PMSG followed by HCG had stimulated the ovarian activity of the control virgin does and elevated the total ovarian response, Metion rate and ovulation percentage. However, administration of low and high doses of lead acetate resulted in a significant decrease in total ovarian response, ovulation rate and ovulation percentage. Lead administration significantly decreased the levels of decteasereins and total lipids. However, a significant increase in the levels of triglycerides was obtained with low and high doses of lead. Cholesterol level was significantly increased with the high dose only. Estradiol-17β and progesterone were significantly decreased following oral administration of both doses of lead acetate. However, lead acetate administration resulted in a significant plasma of bolts were significantly increased with the low and high doses of lead acetate. However, haemoglobin concentration and response with profound changes in the biochemical, haematological and hormonal profiles

Effect of exposure to lead on reproduction in male rats.

The objective of present study was to determine the effect of chronic oral exposure to different levels of lead on male reproductive performance since oral exposure data are more relevant to human environmental exposure. Additionally, most previous results have been obtained after parenteral administration of lead. These experiments were performed on rats by using the incidence of pregnancy to assess male fertility and litter size and pup weight as indicators of the lead effect on perinatal development. Similar parameters were used in reproduction studies by other authors.

Determination of plasma lead levels in normal subjects and in lead-exposed workers.

ABSTRACT Lead levels in whole blood and in plasma were measured in 64 non-exposed and in 29 exposed subjects with signs and symptoms of varying severity. Lead was determined by atomic absorption spectrophotometry after chelation with ammonium pyrrolidine dithiocarbamate and extraction with methyl isobutyl ketone. The method has a sensitivity of 0·4 μg/100 ml (0·02 μmol/l) for whole blood and of 0·2 μg/100 ml (0·01 μmol/l) for plasma and is reliably accurate and precise. Plasma lead increases progressively and significantly with the increase of whole blood lead, while its relative percentage in the plasma remains practically constant at all concentrations in whole blood. In exposed subjects a highly significant correlation was found between lead in plasma and lead in urine (r = 0·549) but the correlation coefficient was higher for whole blood lead versus urinary lead (r = 0·938). Aminolevulinic acid excretion in urine appeared to be significantly related to plasma lead concentration (r = 0·563) but to a greater extent to whole blood levels (r = 0·801). There was no significant correlation between lead in plasma and the logarithm of aminolevulinic acid dehydratase. The hypothesis is advanced that plasma lead, the more biologically active fraction of the metal, could be related to different individual sensitivities which would condition the development of toxic effects in various organs at different levels of lead.

Biologic responses to low level lead exposure.

School of Medicine, Keio University, Tokyo, Japan The purpose of this study was to examine the dose-response relationship in low level lead exposures. Four groups of workers were exposed to four different levels of lead in ambient air. The first group composed of industrial lead workers were exposed to about 7μg/m3, 6 hrs per day, 6 days per week, in an electric wire producing factory. A second group consisting of police-men was exposed to lower lead levels of about 0.5 μg/m3. A third group of rubber hose workers was exposed to the highest lead level of 33 μg/m3 during working hours, and the fourth group (control) consisted of white collar workers from the same electric wire factory as the first group. In these four groups, ALA level in urine, which is believed to indicate the earliest un-desirable biologic effect due to lead, revealed about the same values in all four groups. Only one parameter, blood lead level, was significantly different among the groups. Blood lead level in the rubber hose workers revealed 32 μg/100 ml. The other three groups showed from 15 to 17 μg/100 ml. The lowered hemo-globin level in electric wire workers was found to be related to the educa-tional level of the workers but not to lead in blood, since the control workers showed higher hemoglobin values. Thus it was concluded that the lead level in ambient air which results in recognizable increase of blood lead might exist between 3 to 6 μg/m3.