Effect of cadaverine on Brassica juncea (L.) under multiple stress.

The cadaverine (Cad), an organic diamine was examined for its response on growth in salinity and metal stressed B. juncea cv RH-30 vis-à-vis compared the response of ammonium nitrate. The Cad (1 mM) application ameliorated the effect caused by salinity and metal stress on seed germination and plant growth. The plant growth recovery (dry biomass accumulation) was dependent on stress and diamine type. The higher growth recovery potential of Cad under both stresses was due to elevation in photosynthetic pigments, nitrate reductase activity and organic nitrogen as well as soluble protein, It is inferred that growth in stressed seedlings was mediated by Cad through lowering endogenous Cd/Pb and Na+/K+ level in leaf and shoot tissues.

Metabolismo e toxicidade do chumbo na criança e no adulto / Metabolism and toxicity of lead in children and adults

O chumbo não participa de nenhum passo ou função metabólica essencial ao ser humano. Ao mesmo tempo é o metal não ferroso mais manipulado industrialmente pelo homem desde a antiguidade, o que tem levado à uma contaminação extensa do meio ambiente desde então, proporcionando ainda hoje um aporte regular excessivo desse metal através da ingestão e inalação. Nesta revisão são discutidos aspectos de cinética e dinâmica do chumbo na forma inorgânica, por ser a forma mais comum de apresentação ocupacional e no meio ambiente. Por ser um elemento metálico o chumbo não sofre biotransformação enzimática. O seu “metabolismo” restringe-se a um cinética de distribuição e excreção bastante complexa que, por sua vez, depende da forma química ingerida ou inalada, que definirá seu potencial de oxi-redução e ionização, ligação a proteínas, e passagem por membranas e barreiras, além do acúmulo tecidual e excreção renal. Adultos absorvem até 10% do que é ingerido, em contraste com a taxa das crianças que pode chegar a 50%. Distribui-se fácil e rapidamente por todos os tecidos, além de passar a barreira encefálica e a placentária, sendo secretado no leite materno. As meias vidas de eliminação de chumbo do organismo, conforme o compartimento, podem ser resumidas da seguinte forma: sangue = 25 a 30 dias (em crianças sob exposição ambiental a baixas doses = 10 a 12meses); tecidos moles em geral = 60 dias; osso trabecular = 90 a 120 dias; osso cortical com depósitos estáveis = 25 a 30 anos. Tem ações tóxicas no sistema nervoso central, periférico, renal e hematopoiético principalmente, através de mecanismos que são discutidos no artigo.

Lead does not participate in any metabolic process in humans. Nevertheless, it is the most importantn on ferrous metal in industry since ancient times. This fact promoted a huge and extensive environmental contamination, allowing for an excessive input of lead by humans through ingestion and inhalation. In this review it is discussed aspects of kinetics and toxicity of lead in its inorganic form, being the most important chemical form presenting in occupational and general environment. As a metal, lead does not suffer biotransformation as other toxic substances. Its metabolism is limited to a complex kinetics of distribution and excretion which depends on its chemical speciation, determining the redox potential, rates of ionization and protein binding; crossing of blood brain and placental barriers; rates of tissue accumulation and renal excretion. Adults absorb 10% after lead ingestion, contrasting with children that can absorb 50%. Lead is distributed rapidly and easily through all tissues, including brain, crossing placental barrier and being secreted in maternal milk. Elimination half lifes can be very different according to the body compartment as follows: for blood = 15 to 30 days (in children under low doses of exposure = 10 to 12 months); soft tissues in general = 60 days; trabecular bone = 90 to 120 days; cortical bone with stable deposits = 25 to 30 years. Lead presents toxic action in the central and peripheral nervous system, renal and hemopoietic systems, by toxic mechanisms that are discussed in the paper.

EDTA enhances lead uptake and facilitates phytoremediation by vetiver grass.

Vetiver grass (Vetiveria zizanioides) has strong and dense root system and is a potential phytoremediator plant since it can tolerate a wide range of climatic conditions and grow well in soils contaminated with heavy metals. Soil was artificially contaminated by lead (20 mgl(-1)) during field trials. Four concentration of EDTA (Ethylene diamine tetra acetic acid-disodium salt) solution i.e. 0, 3, 5 and 10 mmol kg(-1) were added to soil prior to harvesting, to study the influence of EDTA solution on phytostabilization by vetiver grass. Results showed that the concentration of lead in roots of vetiver is significantly increased after EDTA solution (5 mmol kg(-1)) application. However, high concentration of EDTA (10 mmol kg(-1)) does not show such significant increase. The toxicity of highly contaminating metal did not affect the growth of vetiver grass significantly but a slight decrease in parameters studied was noticed. No stress symptoms were observed in vetiver plants. Results of present study reveal that vetiver could be considered as a potential phytoremediator for lead contamninated site.

Impact of cadmium and lead on Catharanthus roseus--a phytoremediation study.

The Madagascar Periwinkle, Catharanthus roseus (L.) G. Don (a valued medicinal plant) was exposed to different concentrations ofheavymetals like, CdCl, and PbCl, with a view to observe their bioaccumulation efficiency. Germination was inhibited by both the heavy metals in the seeds previously imbibed in GA, and KNO, for 24 hr. EC50 (the effective concentration which inhibits root length by 50%) was recorded as 180 microM for CdCl2, and 50 microM for PbCl2. Both alpha-amylase and protease activity were reduced substantially on treatment of seeds with increasing concentrations of CdCl2, and PbCl2. Malondialdehyde (MDA) a product of lipoxigenase (LOX) activity also increased due to the treatment of both CdCl, and PbCl2. When two-months-old plants grown in normal soil were transferred to soils containing increasing amounts of these two heavy metals, senescence of lower leaves and extensive chlorosis were noticed after four days of transfer However, plants gradually acclimatized and after 20 days the chlorophyll content was almost comparable to normal. Plants receiving CdCl2 treatment (250 microg g(-1) and less) became acclimatized after two weeks and started normal growth. But PbCl2 of 432 microg g(-1) and less could not affect the plant growth throughout, after a preliminary shock was erased. In case of CdCl2 treatment, a stunted growth with reduced leaf area, reduced biomass and sterility were recorded after six months, while plants show normal growth and flowering in case of PbCl2 treatment. Total alkaloid was also found to be decreased in the roots of CdCl2 treated plants. No change was observed in case of PbCl2. GA3 treatments to the CdCl2 treated plants show internode elongation and increase in leaf area with relatively elongated leaves and thinning of stem diameter AAS analyses of leaves of treated plants exhibited 5-10% accumulation of cadmium, but there was no accumulation of lead at all.

Toxicity and bioaccumulation of cadmium and lead in Salvinia cucullata.

The toxicity and accumulation of heavy metals, cadmium (Cd) and lead (Pb) in aquatic fern, Salvinia cucullata were studied. Plants were cultured in Hoagland's medium which was supplemented with 0.5,1,2, and 4 mg/l of Cd and 5, 10, and 40 mg/l of Pb and were separately harvested after 2,4,6, and 8 days. The toxicity symptoms of Cd and Pb to S. cucullata showed chlorosis on leaves. There were significant derceases in the relative growth, biomass productivity and total chlorophyll content when the exposure time and concentration were increased. The accumulation study showed the significant increases of both metals when the exposure time and concentration were increased. The roots of S. cucullata had higher Cd and Pb contents than leaves suggesting that the metals were bound to the root cells and were partially transported to the leaves.

Accumulation of lead, cadmium and chromium in some plants cultivated along the bank of river Ribila at Odo-nla area of Ikorodu, Lagos state, Nigeria.

Heavy metal in soil samples and in washed and unwashed samples of Telfaria occidentalis (ugwu) and Talinum triangulare (waterleaf) cultivated on the bank of river Ribila in Odo-nla village were determined. The soil was moderately polluted with cadmium when compared with Federal Environmental Protection Agency standards. The difference between the unwashed and washed plant samples revealed that metal pollutants exist as superficial contaminants on the foliage surface which is the edible portion and if the foliage portion is washed thoroughly it may be safe for dietary consumption. There is no doubt that continuous discharge of effluent and gaseous emissions from the industries located in this area and dumping of domestic wastes into the river may lead to higher concentrations of these heavy metals in the soil and in the tissue of the leafy vegetables cultivated on the river bank over time. This can eventually lead to pollution of the soil and the cultivated plants, which are ready source of food for the people and other organisms in the food chain.

Riesgos de contaminación por plomo en una población escolar de la zona sur de Valencia: julio-diciembre 2002 / Blood leald levels and risk factors in school children attending public school in Valencia: July-December 2002

Evaluar los factores de riesgo determinando la relación entre los niveles de plomo en sangre y otros factores; edad, sexo, tiempo de permanencia en la escuela, zona de residencia. El estudio fue conocido de julio a diciembre, 2002 con 50 niños entre 6 y 9 años de edad estudiantes de una escuela pública en el sur de Valencia. Se usó la espectrofotometría de absorción atómica para medir plomo en sangre. Otros datos fueron recolectados con un cuestionario. 25 niños presentaron niveles mayor igual 9,5 mcg/dl. Los varones presentaron mayores niveles. Los niveles elevados fueron más frecuentes a la edad de 7 años, siendo menores en los niños de 6, 8 y 9 años. No se encontró relación entre el tiempo de permanencia en la escuela y niveles elevados; pero sí entre éstos y las zonas de residencia, las cuales presentan condiciones ambientales deficientes; esto indica que posiblemente los niños llegan a la escuela contaminados. Al igual que en estudios previos, los niños presentaron niveles mayores que las niñas, y la edad de 7 años fue la más afectada. Los factores ambientales alrededor de las residencias fueron determinantes. Los resultados son útiles para la planificación y desarrollo de políticas de control ambiental.

Toxicity and accumulation of lead and chromium in Hydrocotyle umbellata.

The aquatic plant, Hydrocotyle umbellata, was studied for its toxicity and accumulation of lead (Pb) and chromium (Cr) in a synthetic solution. Plants were cultured in a modified Hoagland's nutrient solutions supplemented with 20, 40, 60, 80, and 100 mg Pb/l as lead nitrate [Pb(NO3)2] and 2, 4, 6, 8, and 10 mg Cr/l as potassium dichromate (K2Cr2O7). They were separately harvested after 3, 6, 9, and 12 days. Plants exposed to Pb and Cr showed significant decreases in the biomass productivity and total chlorophyll content when the exposure time and metal concentration were increased. The accumulation of Pb and Cr in the plants was significantly increased, but it was not linear with the exposure time and metal concentration. Both metals were accumulated higher in the roots than in the shoots. The bioconcentration factor of Pb was higher than that of Cr at the same exposure time, indicating a higher accumulation potential of Pb than Cr in H. umbellata. Toxicity symptoms of both metals showed a reduction in the production of new plantlets, withering of petioles, and change in color of roots from light green to dark brown. Pb caused leaf chlorosis, whereas Cr caused leaf necrosis. The toxicity symptoms increased when the exposure time and metal concentration were increased.

Studies on the effect of pH on the sorption of Pb2+ and Cd2+ ions from aqueous solutions by Caladium bicolor (Wild Cocoyam) biomass

Environmental protection requires the use of natural products instead of chemicals to minimize pollution. This investigation studies the use of a non-useful plant material as naturally occurring biosorbents for the removal of cationic pollutants in wastewater. The effect of pH on the sorption of Pb2+ and Cd2+ ion onto Caladium bicolor corm biomass was investigated. The experimental results have been analysed in terms of Langmuir, Freundlich and Flory-Huggins isotherms. The data showed that the maximum pH (pHmax) for efficient sorption of Pb2+ was 7.0 and for Cd2+ 5.0. Evaluation using Langmuir equation gave the monolayer sorption capacity as 88.50 mg/g and 65.50 mg/g at the respective pHmax for Pb2+ and Cd2+. Surface characterization of acid and base treated C. bicolor biomass indicates a physiosorption as the predominant mechanism for the sorption process. The thermodynamic assessment of the metal ion - Caladium bicolor biomass system indicates the feasibility and spontaneous nature of the process.

Accumulation of lead and cadmium in upper parts of mustard (Brassica juncea) seedlings in response to putrescine.

Lead and cadmium accumulation examined in shoot and leaf tissues of seedlings of mustard (Brassica juncea cv RH-30), at 7th day, treated with either putrescine (1 mM), or ammonium nitrate (10 mM) or IAA (10 microM). These were included in the nutrient medium, containing Pb or Cd (0.1 mM and 2 mM). Metal accumulation was more in shoot than in leaf tissues, which was increased manifold under saline conditions. However, Cd accumulation in tissues was higher than Pb. Chemical (putrescine, ammonium nitrate or IAA) treatment of the seedlings, decreased metal accumulation in leaf (10-20%) and in shoot (40 to 60%) tissues, depending upon external metal levels. Putrescine significantly decreased the metal accumulation and translocation under saline conditions.

Acumulación de plomo en hueso y sus efectos en la salud / Lead storage in bone and its effects on health

Los efectos nocivos del plomo han sido conocidos desde tiempos antiguos por su amplia gama; este metal afecta prácticamente todos los órganos y sistemas del cuerpo humano. Recientemente todos lo órganos y sistemas del cuerpo humano. Recientemente se han documentado efectos tóxicos crónicos en los sistemas cardiovascular y nervioso, con niveles que antes se consideraban seguros: El sitio primario de almacenamiento de plomo en el organismo es el hueso, pero sólo hasta fechas recientes se ha clarificado la significancia toxicológica de este hecho. En este artículo se analiza el papel del plomo en hueso como fuente de exposición endógena, como biomarcador de exposición crónica y como tejido blanco. Se presentan además los avances recientes para la medición de plomo en hueso mediante los rayos X fluorescentes (XRF). Finalmente se revisa la importancia, para la salud pública, de estudiar y medir el plomo en hueso en lugares con una historia de exposición crónica como la Ciudad de México y en los ambientes ocupacionales, especialmente como fuente remanente de exposición. Se analiza especialmente el caso de mujeres en edad reproductiva, quienes pueden convertirse en fuentes de exposición para el feto y para el niño amamantado

Enolizable carbonyl and imino metabolites may act as endogenous sources of reactive oxygen species

Highly reactive oxyradicals and electronically excited triplet carbonyls can be generated in vitro by iron complexes and heme enzyme-catalyzed aerobic oxidation of synthetic or naturally occurring substances capable of enolization in aqueous medium. Monoenols and enamines, obtained by (alpha-methyne-carbonyl and -imine enolization, undergo dioxygen insertion and ultimately originate triplet species; e.g., isobutanal, 3-methylacetoacetone, Schiff bases. In turn, (alpha-hydroxy- and (alpha-aminocarbonyls (e.g., carbohydrates, 5-aminolevulinic acid) tautomerize to enediols and enolamines and yield oxyradicals, initiated by electron transfer to dioxygen, as polyphenols (e.g., 6-hydroxydopamine) and polyphenolamines do. Free radicals and excited species have been implicated in several normal and pathological processes. We here briefly review our contributions to this research area, emphasizing a possible in vivo prooxidant role for 5-aminolevulinic acid, the heme precursor accumulated in several porphyric disorders (e.g., lead poisoning, acut intermittent porphyria, tyrosinosis).

Metal uptake by mycelia during submerged growth and by sporocarps of an edible fungus Volvariella volvacea.

Uptake of a few metals by V. volvacea was determined during submerged growth of the organism in sublethal concentration of each metal salt. The uptake of Pb2+ and Hg2+ was 5 and 5.23 micrograms g-1 respectively while that of Cu2+ was 500 micrograms g-1 under experimental conditions. Treatment of spawned substrate separately with different metal salts showed maximum and minimum uptake of Pb2+ (100 micrograms g-1) and Cd2+ (2.93 micrograms g-1) respectively by sporocarps. All metal salts at test concentrations reduced biological efficiency of sporocarp production but markedly by Co2+. Cd2+ and Co2+ were highly toxic to mycelia and sporocarps respectively. The uptake of Cu2+ by mycelia and Pb2+ by sporocarps were highest among the five metals tested. Metal toxicity, tolerance and uptake capacity of V. volvacea differ considerably with concentration of metal ions.

Metabolic deficit in rats after low level lead exposure

Male albino rats were injected intraperitonealy with subclinical doses of lead acetate for 50 days to determine any effect on their rate of metabolism. The parameters studied were: 1] The rate of oxygen consumption [Q0[2]] and glucose utilization by cortical brain tissues, liver and kidney slices. b] Liver and kidney function tests viz, SGOT, SGPT and serum creatinine [c] Histopathological examination of the 3 organs to detect any associated damage. The results showed that intraperitoneal injection of rats by the small dose [1 mg] of lead acetate daily for 50 days did not affect significantly all the parameters studied, while marked reduction in Qo[2] and glucose utilization of cortical brain tissues and renal cortical slices and marked increase in serum creatinine, SGOT and SGPT were obtained following injection of the high dose [2 mg daily]. Histopathological examination of the liver, kidney and brain revealed non-specific degeneration which were more apparent on using the higher dose

Estudio de los niveles de excreción de plomo en heces humanas / Lead excretory levels in human feces

Se desarrolló un método para el dosaje de plomo en heces, debido a que en nuestro país se están estudiando tratamientos que favorecerían la excreción fecal de plomo, en pacientes intoxicados con dicho elemento. Se trata 0,5-1,0g de heces con ácido nítrico concentrado y se calienta hasta la destrucción total de la materia orgánica. Después de evaporar el exceso de ácido, se lleva a 2,5 ml con ácido nítrico al 1%. El plomo se cuantifica por espectrofotometría de absorción atómica con atomización en la llama. El método es preciso y sensible. La recuperación de cantidades conocidas de plomo adicionadas a las heces está comprendida entre 93-102%. La concentración de plomo, expresada en microg/g de heces secas, es de 9,9 ñ 2,1 en 35 adultos no expuestos ocupacionalmente y de 5,9 ñ 1,2 en niños de 1 a 10 años

Alteraçöes na atividade da ácido delta-aminolevulínico desidratase (ALA-D) eritrocitária de ratos por metais / Activity changes of delta aminolaevulinic dehydratase acid (ALA-D) in erytrocytes of rats by metals

A administraçäo ad libitum de soluçöes aquosas de chumbo/cobre, chumbo/zinco e chumbo/cromo, a grupos de ratos WISTAR, machos, pesando entre 180 e 200 gramas, por cinco semanas consecutivas provocou inibiçöes da atividade enzimática do ácido delta-aminolevulínico desidratase (ALA-D). As porcentagens de inibiçäo da ALA-D nos grupos expostos em relaçäo ao grupo controle foram, respectivamente, 45,1% para PB2+/Cu2+, 45,1% para Pb2+/Zn2+, 43,1% para Pb2+/Cr3+ e 27,4% para Pb2+/Cr6+/. Os resultados sugerem internaçöes entre esses elementos, quer ao nível de absorçäo e/ou transporte, ou ainda, através de interferências na atividade da ALA-D

Concentración de plono en el tejido muscular de Merluza (Merluccius gayi) / Lead concentration in muscular tissue of Merluza (Merluccius gayi)

El contenido de Pb en la masa muscular de merluza (Merluccius gayi) obtenida aleatoriamente del muelle de desembarque de productos marinos de San Antonio (Chile, V Región), se midió mediante Espectrofotometría de Absorción Atómica, previa digestión ácida por vía seca. De un total de 120 muestras, el nivel promedio de plomo detectado fue de 0,72 + ou - 0,31 mg/kg base húmeda, concentración que supera la ingesta máxima permisible de este elemento en alimentos establecida por FAO/OMS, la que no debe exceder de 0,45 mgPb/día. Estos resultados pueden significar peligrosas consecuencias ecológicas, alimentarias y para la salud. Resulta conveniente, por tanto, identificar las causas de esta contaminación, con el fin de plantear soluciones adecuadas