Dietary intake of potentially toxic elements from vegetables

Toxic elements e.g B,arsenic(As),cadmim (Cd),ChrOmium(Co,COpper(Cu),lCad (Pb),and zinc(Zn)are the chief envÞolllnental pollutants which can cause deleterious health effects ill humans.Inhalation and consumption ofrnetal c conta \ated food are the mttOr pathways of metal entrance into hman body.Cuhivation of crop plants in the metal \ contaminated soils induces the bioaccllmlllation of toxic elements in the food chain.Among different food items,vegetables have mttOr cOntribution in the daily dict, and the heavy inetal contamination ofvegetables poses a threat to human health with the prevalence of skin and gastrointerestinal cancer

Arsenic-induced straighthead: An impending threat to sustainable rice production in South and South-East Asia!

Straighthead is a physiological disorder of rice (Oryza sativa L.) that results in sterile florets with distorted lemma and palea, and the panicles or heads may not form at all in extreme cases. Heads remain upright at maturity, hence the name 'straighthead'. The diseased panicles may not emerge from the flag leaf sheath when the disease is severe. Straighthead disease in rice results in poorly developed panicles and significant yield loss. Although other soil physicochemical factors involved, arsenic contamination in soil has also been reported to be closely associated with straighthead of rice. Monosodium methanearsonate has been a popular herbicide in cotton production in the USA, which has shown to cause injuries in rice that are similar to straighthead. Since toxicity of inorganic arsenic (iAs) is higher than other forms of arsenic, it may produce a more severe straighthead disorder in rice. The use of iAs-rich groundwater for irrigation, and the increase of iAs concentrations in agricultural soil in arsenic epidemic South and South-East Asia may cause a high incidence of straighthead in rice, resulting in a threat to sustainable rice production in this region. © 2011 Springer Science+Business Media, LLC

Eutrophication and arsenic speciation in lake waters

Arsenic (As) is widely distributed in aquatic environments in various forms. In natural waters, the dominant inorganoarsenicals (iAs) are incorporated into microorganisms such as phytoplankton, and are converted to methylarsenicals and/or more high order organoarsenicals. In addition, the organoarsenicals are mineralized to iAs and methylarsenicals by bacteria. The cycling of As species would depend on the bioactivity of organisms. Microorganisms, such as phytoplankton and organisms of higher trophic levels, produce methylarsenicals in natural waters with maximum concentrations in summer. The degradation and mineralization of organoarsenic compounds are thought to depend mostly on bacterial activities, which influence the As cycling in aquatic environment. Arsenic metabolism in aquatic organisms results in the occurrence of thermodynamically unstable arsenite and methylarsenic compounds in natural waters. The inorganic forms (As(V) and As(III)) and the methylated forms (methylarsonic acid (CH3AsO(OH)2); MMAA(V) and dimethylarsinic acid ((CH3)2AsO(OH)); DMAA(V)) are the main arsenic species present in natural waters. Although the predominant form of methylarsenicals is consistently DMAA(V) followed by MMAA(V), the existence of trivalent methylarsenic species in the environment has also been reported.Researchers reported the correlation between As(III)/methylarsenicals and chlorophyll-a concentrations and/or phytoplankton density, while others found that the seasonal changes of DMAA concentration is related to the temperature rather than the biological activity of phytoplankton. Eutrophication increases the concentration of nutrient salts and multiplies the primary producers, such as phytoplankton, in lake water. Lakes progress through the oligotrophic, mesotrophic and eutrophic process in the natural environment, and these transitions are very slow. Recently, the transition speed became faster because of discharged pollutants and nutrients from human activities, and the eutrophication affects the As circulation in lakes. Very recently, reports showed that the eutrophication influences As speciation in lake water too. In this chapter, the influence of eutrophication on arsenic speciation will be discussed. © 2010 Nova Science Publishers, Inc. All rights reserved

Ecosystem aspects of arsenic poisoning: Human exposure to arsenic from food chain

Although the main source of arsenic to human body is ground water, the use of arsenic contaminated ground water for irrigation gives rise to the question whether arsenic uptake in crop plants could also be another potential pathway of human exposure to arsenic. Arsenic content in straw, grain and husk of rice is especially important as rice is the staple food for man and straw and husk have been used as cattle feed. It was estimated that the daily intake of arsenic in human body from rice (containing 0.40 mg As/kg, the highest concentration of arsenic found in the present experiment in treatment containing 40 mg As/kg soil) is 0.20 to 0.32 mg/day (as the average consumption of rice by the people above five years old is between 400 and 650 gm/day) whereas it is 0.20 mg/day from drinking water (as the recommended safe level arsenic in drinking water is 0.05 mg As/l for Bangladesh and the average intake of water by an adult is about four litres). This finding suggests that arsenic intake in human body through rice could be a potential pathway in addition to drinking water. Therefore, a hypothesis have been put forward that the human beings have not been suffering from arsenicosis only from drinking water but also from "Plant-Animal-Man" and some other food chain pathway

Phytotoxicity of arsenate and salinity on early seedling growth of rice (oryza sativa l.): A threat to sustainable rice cultivation in South and South-East Asia

Arsenic (As) contamination is an important environmental consequence in some parts of salinity-affected South (S) and South-East (SE) Asia. In this study, we investigated the individual and combined phytotoxicity of arsenic (As) [arsenate; As(V)] and salinity (NaCl) on early seedling growth (ESG) of saline-tolerant and non-tolerant rice varieties. Germination percentage (GP), germination speed (GS) and vigor index (VI) of both saline-tolerant and non-tolerant rice varieties decreased significantly (p[0.01) with increasing As(V) and NaCl concentrations. The highest GP(91%) was observed for saline non-tolerant BRRI dhan28 and BRRI dhan49, while the lowest (62%) was for salinetolerant BRRI dhan47. The ESG parameters, such as weights and relative lengths of plumule and radicle, also decreased significantly (p\0.01) with increasing As(V) and NaCl concentrations. Relative radicle length was more affected than plumule length by As(V) and NaCl. Although VI of saline-tolerant and non-tolerant rice seedlings showed significant variation (p\0.05), weights and lengths of plumule and radicle of different rice varieties did not show significant variation for As(V) and NaCl treatments. Results reveal that the combined phytotoxicity of As(V) and NaCl on rice seed germination and ESG are greater than their individual toxicities, and some saline-tolerant rice varieties are more resistant to the combined phytotoxicity of As(V) and NaCl than the saline non-tolerant varieties. © Springer Science+Business Media, LLC 2012

Aquatic arsenic: Phytoremediation using floating macrophytes

Phytoremediation, a plant based green technology, has received increasing attention after the discovery of hyperaccumulating plants which are able to accumulate, translocate, and concentrate high amount of certain toxic elements in their above-ground/harvestable parts. Phytoremediation includes several processes namely, phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization. Both terrestrial and aquatic plants have been tested to remediate contaminated soils and waters, respectively. A number of aquatic plant species have been investigated for the remediation of toxic contaminants such as As, Zn, Cd, Cu, Pb, Cr, Hg, etc. Arsenic, one of the deadly toxic elements, is widely distributed in the aquatic systems as a result of mineral dissolution from volcanic or sedimentary rocks as well as from the dilution of geothermal waters. In addition, the agricultural and industrial effluent discharges are also considered for arsenic contamination in natural waters. Some aquatic plants have been reported to accumulate high level of arsenic from contaminated water. Water hyacinth (Eichhornia crassipes), duckweeds (Lemna gibba, Lemna minor, Spirodela polyrhiza), water spinach (Ipomoea aquatica), water ferns (Azolla caroliniana, Azolla filiculoides, and Azolla pinnata), water cabbage (Pistia stratiotes), hydrilla (Hydrilla verticillata) and watercress (Lepidium sativum) have been studied to investigate their arsenic uptake ability and mechanisms, and to evaluate their potential in phytoremediation technology. It has been suggested that the aquatic macrophytes would be potential for arsenic phytoremediation, and this paper reviews up to date knowledge on arsenic phytoremediation by common aquatic macrophytes. © 2011 Elsevier Ltd

Agro-industrial development and sustainability in Bangladesh-A study

A study was conducted to know the current state of development sustainability of the agroindustrial sector in terms of its product diversity, export volume, export value, destination of the product by region and country. A structured questionnaire was prepared to do the random sampling survey and focused group discussion also held with the relevant stakeholder in agro-industrial sphere. The study revealed that in terms of value, the highest exported agro processed product is spices 21.46 million US$(25$ 70.13 million. In terms of export value, the major destination of Bangladesh agro-processed product is Kingdom of Saudi Arabia(KSA) which amount is 20.2 million US$. In terms of export in weight, the major destination of Bangladesh agro-processed product is India (24372.88 metric ton).Int. J. Agril. Res. Innov. & Tech. 5 (2): 37-43, December, 201

Effects of periphyton on monoculture of Puntius gonionotus

An experiment was carried out on the effects of periphyton on monoculture of Thai sharputi, Puntius gonionotus at the Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh during 7th August to 8th November. In treatment-1 bamboo poles were used as artificial substrate for periphyton production and in treatment-2 there was no artificial substrate (control). Each of the six ponds was stocked with 150 fingerlings of average size 6.41 cm and 3.60 g. The ponds were fertilized fortnightly with manure (cow dung) at a rate of 10 kg decimal-1, urea 60 g decimal-1 and triple super phosphate 90 g decimal-1. During the experimental period, the ranges of physico-chemical parameters viz. air temperature (31.0-35.50C), water temperature (29-320C), water depth (0.56-0.84 m), transparency (32-63 cm), dissolved oxygen (3.5-7.8 mg L-1), pH (6.8-7.9), total alkalinity (44-92 mg L-1), free CO2 (1.5-4.0 mg L-1), phosphate-phosphorus (0.31-1.07 mg L-1) and nitrate-nitrogen (1.12-2.30 mg L-1) were within the productive range and more or less similar in the ponds under treatments-1 and 2. Among the observed biological parameters, there were 35 genera of phytoplankton composed of five groups and 13 genera of zooplankton composed of four groups in the experimental ponds. Thirty three genera under the groups of Bacillariophyceae, Chlorophyceae, Cyanophyceae and Euglenophyceae formed the periphyton on bamboo poles in the experimental ponds. Net fish production of the ponds with periphyton under treatment-1 was about 1.5 times higher than those of the ponds without periphyton (treatment-2). By analysis of variance, it was found that the net fish production of Thai sharputi under treatment-1 was significantly higher than that under treatment-2 (p< 0.05). Finally, it can be concluded that periphyton is one of the preferable food item of Thai sharputi and it is also suggested that growth and production of Thai sharputi can be increased if arrangement is made for periphyton production. Int. J. Agril. Res. Innov. & Tech. 8 (2): 13-23, December, 201