Utilization of nSiO2, fly ash, and nSiO2/fly ash composite for the remediation of triphenyltin (TPT) from contaminated seawater

The removal of triphenyltin chloride from contaminated simulated seawater with adsorption method was discussed. The adsorbents used are fly ash, nSiO₂, and nSiO₂/fly ash composite. The results showed that the adsorption of the adsorbents increases with increase in the adsorbent dose, contact time, pH, stirring speed, initial TPT concentration, and decreased with increase in temperature. The adsorption fitted well with the Freundlich isotherm, showing that the adsorbent and TPT combined with function groups and the adsorption kinetics followed the pseudo-second-order kinetic model. The thermodynamic parameters were also evaluated. Optimal conditions for the adsorption of TPT from simulated seawater were applied to TPT removal from natural seawater. A higher removal efficiency of TPT (>99 %) was obtained for the nSiO₂/fly ash composite but not for fly ash and nSiO₂.     

Effect of white African mineral hair dye on the activities of phosphatases and malondialdehyde level in selected tissues of albino rats

The effect of white African mineral dye Yombofita (YF) on the activities of alkaline phosphatase (ALP), acid phosphatase (ACP) and malondialdehyde (MDA) levels in the skin, liver, kidney and serum of albino rats was investigated. The chemical analysis of the dye was first carried out using solubility test, pH determination and X-ray fluorescence (XRF) elemental analysis. Six different concentrations (0.05, 0.15, 0.25, 0.5, 0.75 and 1.00%) of the dye were prepared using hydrogen peroxide (30 volume) as solvent. A total of 80 albino rats (Rattus norvegicus) were used for the study. The rats were divided into 8 groups of 10 each and were maintained on commercial feed for the period of the experiment i.e. 30 days. In group 1, the control group, the animals were applied distilled water on their heads, whereas in group 2 the vehicle i.e. hydrogen peroxide was applied. In groups 3 to 8 various concentrations of YF (white) dye ranging from 0.05, 0.15, 0.25, 0.5, 0.75 to 1.00% was applied respectively. At the end of the experiment, blood samples were collected and portions of the selected tissues were excised for the determination of ALP and ACP activities. The MDA level was also determined in the skin of experimental animals. The results revealed a significant decrease (p?p?相似文献   

Spectroscopy properties and optimization for the detection of mercury（Ⅱ） with series hydroxyl-porphyrins

结合紫外分光光度法研究系列羟基卟啉与汞离子的显色反应,并优化其检测条件.在pH=7.5的条件下,以N,N-二甲基甲酰胺（DMF）作为溶剂,加入0.4 mL表面活性剂Tween-80,系列羟基卟啉与Hg2＋发生配位反应,发现其最大吸收峰与卟啉环上（meso）位苯基对位上的羟基数目相关.热力学研究表明,单羟基卟啉化合物对Hg2＋检测效果最好,形成1∶1配位化合物,检测限可达0.042μg.L-1,且在0—50 mg.L-1范围内符合比尔定律.     

Contrasts in Livelihoods and Protein Intake between Commercial and Subsistence Bushmeat Hunters in Two Villages on Bioko Island,Equatorial Guinea

Across West and Central Africa, wildlife provides a source of food and income. We investigated the relation between bushmeat hunting and household wealth and protein consumption in 2 rural communities in Bioko Island, Equatorial Guinea. One village was dedicated to commercial hunting, the other trapped game primarily for food. We tested whether commercial‐hunter households were nutritionally advantaged over subsistence‐hunter households due to their higher income from the bushmeat trade and greater access to wild‐animal protein. We conducted bushmeat‐offtake surveys in both villages (captures by hunters and carcasses arriving to each village). Mammals (including threatened primates: black colobus [Colobus satanas], Preussi's guenon [Allochrocebus preussi], and russet‐eared guenon [Cercopithecus erythrotis]), birds, and reptiles were hunted. The blue duiker (Philantomba monticola), giant pouched rat (Cricetomys emini), and brush‐tailed porcupine (Atherurus africanus) contributed almost all the animal biomass hunted, consumed, or sold in both villages. Monkeys and Ogilbyi's duikers (Cephalophus ogilbyi) were hunted only by commercial hunters. Commercial hunters generated a mean of US$2000/year from bushmeat sales. Households with commercial hunters were on average wealthier, generated more income, spent more money on nonessential goods, and bought more products they did not grow. By contrast, households with subsistence hunters spent less on market items, spent more on essential products, and grew more of their own food. Despite these differences, average consumption of vegetable protein and domestic meat and bushmeat protein did not differ between villages. Our results highlight the importance of understanding the socioeconomic and nutritional context of commercial and subsistence bushmeat hunting to correctly interpret ways of reducing their effects on threatened species and to enable the sustainable offtake of more productive taxa. Contrastes en el Sustento y la Ingesta de Proteínas entre Carne de Caza de Subsistencia y Comercial en Dos Aldeas en Isla Bioko, Guinea Ecuatorial     

Comparative study of the age and location dependence of some heavy metals in human hair from two Nigerian cities

The concentration of some heavy metals (lead, zinc and copper) were determined in the scalp hair of children (1–15 year) and active adults (16–40 year) in two Nigerian cities. The levels of zinc were found to be higher in children than in the adult population. There was a significant difference (P?=?0.05) between the two age groups. The levels of copper were all within the same range for the two age groups and independent of location. The levels of lead were generally higher in adults than in children. However, there was no significant difference (P?=?0.05) in the average concentrations of lead between the children and adult populations of the two cities. The regression analysis indicated a strong correlation (r?=?0.86) between zinc and copper.     

Bioaccumulation of metals in black mussels (Mytilus galloprovincialis) in Cape Town Harbour, South Africa

Heavy metal concentrations in black mussels (Mytilus galloprovincialis) collected from Cape Town Harbour were determined using energy dispersive X-ray fluorescence (EDXRF) and inductively coupled plasma-mass spectrometry (ICP-MS). EDXRF showed that tissue portions of the mussels contained K, Ca, Fe, Cu, Zn, Si, Sr, Al and Au, while the shell portion contained K, Ca, Fe, Cr, Zn, Si and Sr. In addition to these metals, EDXRF also revealed the presence of Al in the shells of the largest mussels. Highest concentrations of Cu and Zn were recorded in the tissues of the smallest mussels. Due to poorer detection limits of EDXRF, ultra-trace elements (Mn, Pb, As, Hg, V, Cr, Sn, Cd, Ni and Co) were determined in mussels using ICP-MS. The average metal concentrations found in the mussels are as follows; Pb (7.30 ± 0.67), Cd (1.98 ± 0.13), Hg (4.92 ± 0.60), As (6.94 ± 0.04), Sn (2.63 ± 0.13), Ni (1.88 ± 0.05), Cr (3.54 ± 0.05), V (4.17 ± 0.23), Co (0.74 ± 0.01) and Mn (35.20 ± 1.46). ANOVAs, Pearson correlation and principal component analysis (PCA) were employed in data analysis. The order of the abundance of metals in the mussels is Mn > Pb > As > Hg > V > Cr > Sn > Cd > Ni > Co. The average metal concentrations found in the mussels were higher than the permissible Food and Agriculture Organization (FAO) limits and other international guidelines.     

A media framing analysis of urban flooding in Nigeria: current narratives and implications for policy

Regional Environmental Change - A critical element of current flood management is the importance of engaging key policy actors when policy decisions are to be made. However, there is still only...     

Determination of concentration of heavy metals in two common fish species from asa river,ilorin, nigeria

Concentrations of some heavy metals in Tilapia zilli (Tilapia) and Synodontis membrane (Catfish), the two common fishes from Asa River Ilorin, Nigeria have been determined. Manganese, zinc, iron, and lead, were present at appreciable concentrations in the tissues of the two species while cadmium, mercury, and nickel, were found to be less than 0.01?ppm. Concentrations of metals were highest downstream than at upstream locations. Mean concentrations of Mn in Tilapia, ranged between 0.56?ppm at the upstream end and 2.69?mg/kg of fresh weight at the downstream end. Pb, Zn, and Cr ranged between 4.05 and 5.59?mg/kg of fresh weight, 0.09 and 1.16?ppm, 5.62 and 11.15?ppm, and 0.09 and 0.13?ppm respectively. In the Catfish, Mn, Fe, Zn, and Cr ranged between 0.62 and 0.78?ppm, 3.79 and 8.79?ppm, 0.78 and 1.57?ppm, 7.30 and 15.15, and 0.23 and 0.35?ppm respectively. Heavy metals except lead did not pose any health risks in human since the calculated probable amounts being ingested by an average adult (50?kg average weight) per day were lower than WHO maximum recommended value of intake. However, the level of lead was higher than WHO limit and this could render inedible the fishes from this catchment river.     

大孤山铁矿边坡爆破损伤分区研究

露天矿生产爆破,特别是靠帮爆破在边坡中形成的爆破损伤区对其稳定性具有很大的影响。本文针对大孤山铁矿露天爆破开采的实际情况,建立了极限平衡数值分析模型及峰值速度衰减公式。利用数值分析软件Geoslope对边坡靠帮爆破过程中岩体损伤范围进行了研究,主要分析了在爆破-200--212m水平时,爆破震动对边坡岩体的影响,并利用萨道夫斯基公式和PPV安全判据对爆区周围岩体损伤范围进行了计算。结果表明距离炮孔6.2m以内范围为完全破碎区,6.2-12.4m为岩体重度损伤区,12.4-19.7m为轻微损伤区。数值分析表明距爆源同一距离的岩体质点峰值速度随深度的增加而减小,爆破区周围震动波速成漏斗形分布,同实际爆破情况吻合。