Implementation of food frequency questionnaire for the assessment of total dietary arsenic intake in Bangladesh: Part B, preliminary findings

Dietary intake of water and food has been identified as one of the major pathways for arsenic (As) exposure in the rural population of Bangladesh. Therefore, realistic assessment and measurement of dietary intake patterns are important for the development of an accurate estimate of As exposure and human health risk assessment. One important consideration is to identify an appropriate tool for measuring dietary intake. In this study an interviewer-administered Food Frequency Questionnaire (FFQ) was implemented to determine age and gender specific dietary intake. The developed FFQ was unique because it developed a synergy between field dietary assessment and As concentration measurements in various environmental media. The resulting integrated database provided an accurate framework for the process of As exposure and human health risk assessment. The preliminary results reported here from the FFQ demonstrated that this technique could be used in rural areas as a tool to assess As exposure and the associated human health risk.     

Sediment accumulation and bio-diffusion mixing rates derived from excess <Superscript>210</Superscript>Pb and <Superscript>137</Superscript>Cs profiles in sediment cores of Mumbai Harbor Bay

Bio-diffusion mixing rates (D_b) were estimated from depth profiles of excess ²¹⁰Pb and ¹³⁷Cs in three sediment cores collected from Mumbai Harbour Bay (MHB) using a steady state vertical advection - diffusion model. The mean of ²¹⁰Pb and ¹³⁷Cs derived D_b values along the studied area were obtained to be about 23 and 36 cm²y^?1 respectively. These derived values were within the range of literature values reported for other equivalent environment internationally. The relatively higher D_b values for ¹³⁷Cs profiles demonstrated that particles have diffused more intensely within the surface layer of sediments over 1 year. Conversely, low D_b values for ²¹⁰Pb indicate slow mixing rates in the sediment profile which might be resulted from low ²¹⁰Pb flux and diffusion of ²²²Rn to the seafloor. The significant differences between ²¹⁰Pb and ¹³⁷Cs derived D_b values among cores indicate that there appeared to be as regional differences in sediment properties and local variability in the intensity of seafloor mixing. Furthermore, D_b values also depend on differences in characteristic time and depth scales of radionuclides in cores, benthic fauna abundances, organic carbon flux to the sediments and primary production in overlying surface waters. Comparison of ²¹⁰Pb derived D_b values with those calculated from ¹³⁷Cs distributions reveals better agreement for core 2 than core 1 and 3. The agreement may be fortuitous because ¹³⁷Cs appears significantly deeper than ²¹⁰Pb in all cores. It was also observed that D_b values increases as sediment accumulation rate increases for both radionuclide.     

近海沉积物DlPCBs对斑马鱼胚胎EROD和cyp1a mRNA的影响

为探究湛江近海域海洋沉积物中类二噁英多氯联苯(dioxin-like polychlorinated biphenyls,Dl PCBs)的生物学毒性效应,选取湛江近海域2个地点(近工业区TS和近生活区JSW)采集沉积物样品,制备近海域沉积物Dl PCBs提取物,将斑马鱼胚胎暴露于不同浓度的Dl PCBs提取物,测定斑马鱼胚胎7-乙氧基异吩恶唑脱乙基酶(ethoxyresorufin-O-deethylase,EROD)活性和cyp1a m RNA相对表达量。结果发现,JSW采样点Dl PCBs提取物染毒组EROD酶活性变化与TS采样点Dl PCBs提取物一致,在各染毒浓度下,斑马鱼仔鱼EROD酶活性为对照组的1.1~1.8倍。TS和JSW采样点不同浓度Dl PCBs提取物暴露斑马鱼胚胎96 h后,使斑马鱼仔鱼cyp1a m RNA相对表达量是对照组的3.36~19.45倍。说明一定浓度的近海沉积物Dl PCBs能诱导斑马鱼仔鱼EROD酶活性和cyp1a m RNA表达量升高,且呈现浓度-效应关系。     

Neuroprotective potential of N -acetylcysteine in carbofuran neurotoxicity: A biochemical and histopathological study

The present study was undertaken to evaluate biochemical markers of chronic carbofuran exposure to rats in terms of lipid peroxide and intrasynaptosomal calcium levels and to correlate them with the histopathological changes in brain regions. A significant increase in lipid peroxidation (LPO) in terms of thiobarbituric acid reactive substances (TBARS) was observed in the cerebral cortex (65%) and brain stem (33%) after carbofuran exposure. This was accompanied by a significant increase (87%) in the intracellular free-Ca²⁺ [Ca²⁺]_i levels. N-acetylcysteine (NAC) administration, on the other hand, reversed the carbofuran-induced increase in LPO and [Ca²⁺]_i. Histopathological studies of carbofuran-exposed brain revealed high frequency of pyknotic neurons in the cerebral cortex and microhaemorrhages in the brain stem. NAC supplementation to carbofuran-treated animals resulted in normalisation of the brain architecture as seen by a reduction in the number of pyknotic nuclei in the cerebral cortex. These findings indicate that increased LPO and elevated [Ca²⁺]_i levels are involved in the development of carbofuran neurotoxicity and are eventually responsible for the pathological alterations. The study also demonstrates potential neuroprotective effect of NAC treatment in carbofuran neurotoxicity.     

Effect of nickel exposure on serum amylase activity in nickel-plating workers

The objective of this study was to determine the effect of nickel (Ni) exposure on serum amylase activity in nickel-plating workers in Bangalore (India). Sixty-nine subjects using Ni during the electroplating process formed the exposed group. An equal number of age- and sex-matched subjects working in the administration section formed the control group. Urine Ni levels were determined using a flameless atomic absorption spectrophotometer. Serum amylase activity was determined using spectrophotometric method with 2-chloro-4-nitrophenyl-α-D-maltotrioside as substrate. A significant increase in urine Ni and serum amylase activity was noted in nickel platers as compared with the control group. The level of serum amylase activity was positively and significantly associated with Ni content in urine of nickel platers. Stepwise multiple regression analysis was used to assess the effects of Ni exposure, life style confounding factors and presence of gastrointestinal problems on serum amylase activity. The analysis showed that the subjects who had urine Ni levels beyond 10?µg?g^?1 of creatinine, nickel platers category, smoking and body mass index variables were significantly associated with serum amylase activity. The results of this study suggest that the increased serum amylase activity observed in nickel-exposed subjects could be used as a biomarker for investigating pancreatic function in Ni exposure.     

Vitamin E-mediated protection on methomyl-induced alterations in rat liver

The present study was carried out to observe the possible beneficial effects of Vitamin E, a natural antioxidant on methomyl-induced biochemical and histological alterations in rat liver. To carry out the investigations, animals were segregated in four different groups. Animals in Group I served as normal controls. Animals in Group II were given single methomyl dose orally in water (9 mg kg^?1 b.wt). Animals in Group III were injected intraperitoneally with Vitamin E (50 mg kg^?1 b.wt) for 1 week on alternate days. Animals in Group IV were administered Vitamin E 1 week before subjecting them to methomyl treatment. Animals in all the groups were sacrificed 24 h after the end of treatments. Different biochemical estimations were carried out, which included estimation of aspartate aminotransaminase (AST), alanine aminotransaminase (ALT), alkaline phosphatase (ALP) and acetylcholinesterase (AChE). Further, to examine the oxidative damage lipid peroxidation (LPO) and glutathione (GSH) levels as well as antioxidant enzymes such as superoxide dismutase (SOD), catalase, glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GSHPx), and glutathione-6-phosphate dehydrogenase were estimated in liver samples. AchE activity was inhibited significantly both in serum and liver following methomyl treatment. Administration of methomyl caused a significant increase in serum AST, ALT and ALP which indicated hepatic damage. LPO was found to be significantly increased, whereas GSH levels were decreased in the liver of methomyl-treated animals. The activities of SOD and catalase were significantly decreased whereas GST and GSHPx activities were found to be elevated significantly following methomyl treatment. No significant change in the enzyme activity of GR and glutathione-6-phosphatase dehydrogenase was observed after methomyl treatment. Vitamin E supplementation was able to attenuate appreciably the methomyl-induced changes in LPO levels along with SOD and GST activities. Histopathological studies following methomyl treatment revealed that hepatocytes, were not very well delineated and nuclei showed degenerative changes. Whereas, following Vitamin E supplementation in combined treatment group nuclei showing degenerative changes become less in number. The study, therefore, concludes that Vitamin E has a potential in mitigating most of the adverse effects induced by methomyl acute toxicity.     

Extraction of arsenic species in soils using microwave-assisted extraction detected by ion chromatography coupled to inductively coupled plasma mass spectrometry

We have developed a novel microwave-assisted extraction method for determining the arsenic (As) speciation in soils that is based on extraction with phosphate solutions, including orthophosphoric acid, ammonium dihydrogen orthophosphate, and ammonium hydrogen orthophosphate. The highest extracting efficiency was obtained with 1 M ortho-phosphoric acid solution as the extractant, and this efficiency is associated with the pH of the extractant. Total As content and As species in the soil extracts were determined by inductively coupled plasma mass spectrometry (ICP-MS) alone and by the combined ion chromatography (IC) with ICP-MS, respectively. The proposed extraction procedure was applied to National Institute of Standards and Technology (NIST) standard reference material (SRM) 2711 (Montana soil) as well as to environmental soil samples collected from the agricultural lands of Bangladesh. As(V) was detected in all the soil samples, and As(III) was detected in nine soils of the 20. These results of extractable As testing indicate that the extraction of As species mainly depends on the composition of the soils. The As speciation results also indicate that As adsorption is highly dependent on the iron, aluminum, and manganese concentrations in the soil. The stability of As species in the extracts was also studied.     

Nanostructured semiconducting materials for efficient hydrogen generation

Massive production of hydrogen by water decomposition triggered by a solar light active photocatalyst is a major objective in chemistry and a promising avenue to overcome the global energy crisis. The development of efficient, stable, economically viable and eco-friendly photocatalysts for hydrogen production is a challenging task. This article reviews the use of nanocomposite in three combinations: metal oxide–metal oxide semiconductor, metal–metal oxide semiconductor and metal chalcogenide–metal oxide core–shell nanostructures. These core–shell structures occur in two forms: a simple form where the photocatalyst is either in the core or the shell or in a more complex system where the core–shell structure comprises a co-catalyst deposited on a semiconducting material. We discuss the design, synthesis and development of semiconductor-based nanocomposite photocatalysts for hydrogen production. The major points are the role of catalytic active sites, the chemical nature of sacrificial agents, the effect of light sources, the variable light intensity and the energy efficiency calculation. For TiO₂-based nanocomposites, the metal oxide or metal co-catalyst loading of 1.0–3.0 wt% was optimal. TiO₂ nanotube–CuO hybrid nanocomposites produce 1,14,000 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\), whereas TiO₂/Au nanocomposites display 1,60,000 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\). For core–shell catalysts, a shell thickness of 2–20 nm was found for the best activity, and its performance is as follows: (a) CdS–NiO system produces around 19,949 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\) and (b) CuO–Cr₂O₃ as co-catalyst immobilized on TiO₂ system produces around 82,390 µmol h^?1 \({\text{g}}^{ - 1}_{\text{cat}}\).     

锁磷剂联合好氧反硝化菌修复富营养化水体

氮磷是造成水体富营养化的主要原因,单一治理方法常常难以同时有效去除氮磷.本文利用1株分离自富营养化水体的好氧反硝化菌株（AD-19）构建固定化菌膜,并与锁磷剂Phoslock^®联合修复富营养化水体,研究了Phoslock^®的控磷效能和反硝化菌的脱氮性能及二者联合作用时对富营养化水体的修复效果.结果表明,在投加比例为80（Phoslock^®与PO₄^3--P的质量比）的条件下,Phoslock^®对模拟富营养化水体中PO₄^3--P去除率可达95%以上,并能有效抑制底泥中磷的释放.好氧反硝化菌AD-19具有较好的异养硝化-好氧反硝化功能,在以NH₄⁺-N或NO₃^--N为唯一氮源条件下生长良好并能去除97%以上的氮,经16S rDNA鉴定该菌株属于假单胞菌属（Pseudomonas sp.）.利用湖泊模拟装置论证了Phoslock^®联合固定化菌膜修复富营养化水体的可行性,进一步地,利用该技术对武汉市某公园内富营养化池塘进行修复治理,经过16 d的处理,氮磷等水质指标从劣Ⅴ类地表水提升至Ⅲ类,并持续稳定270 d以上,证明Phoslock^®联合固定化菌膜可快速和有效地修复富营养化水体,并保持水质长期稳定.     

Analysis of local perspectives on sustainable forest management: an Indonesian case studyThis study was funded through a collaborative project between the University of Illinois and the Center for International Forestry Research (CIFOR). The ideas contained herein are solely of the authors and do not necessarily reflect official views of CIFOR

Despite widespread acceptance of sustainability as the ultimate goal of forest management, perspectives about its meaning, significance, and relevant indicators may still differ. This paper examines local perspectives on sustainability, and evaluates their similarities and differences. A systematic procedure based on criteria of proximity, pre-existing rights, dependency, knowledge of forest management, forestry spirit, daily activity, and legal rights was used to identify a small group of relevant stakeholders representing different groups, institutions, and organizations. Using participatory action research (PAR), stakeholders were asked to identify relevant indicators of sustainable forest management. The indicators identified by each stakeholder were then compared to a consolidated list assembled by field facilitators with respect to whether relevant indicators are present or not. Based on the resulting presence/absence matrix, a statistical tool called the simple matching coefficient was used to estimate the similarity measures among the stakeholders' perspectives. In addition, cluster analysis was used to classify groups of stakeholders depending on their similarities to each other. Finally, hypotheses related to the 'closeness' of perspectives among local communities, non-governmental organizations, a timber company, and government organizations, as revealed by their selection of indicators, were tested. Results show that: (a) local communities have different perceptions in terms of what they consider to be important indicators compared to the NGOs, (b) there are significantly different perceptions between the government and the timber companies, and (c) there are also different perceptions between urban and field-based personnel of the same organization.