Geological sources of fluoride and acceptable intake of fluoride in an endemic fluorosis area, southern Iran

The present study is the first attempt to put forward possible source(s) of fluoride in the Dashtestan area, Bushehr Province, southern Iran. In response to reports on the high incidence of dental fluorosis, 35 surface and groundwater samples were collected and analysed for fluoride. The results indicate that dissolved fluoride in the study area is above the maximum permissible limit recommended by the World Health Organization (WHO). An additional 35 soil and rock samples were also collected and analysed for fluoride, and rock samples were subjected to petrographic investigations and X-ray diffraction. The results of these analyses show that the most likely source for fluoride in the groundwater is from clay minerals (chlorite) and micas (muscovite, sericite, and biotite) in the soils and rocks in the area. We also note that due to the high average temperatures all year round and excessive water consumption in the area, the optimum fluoride dose level should be lower than that recommended by the WHO.     

226Ra concentration in the teeth of habitants of areas with high level of natural radioactivity in Ramsar

The level of natural radiation in some regions of Ramsar, a northern coastal city of Iran, is known to be among the highest levels of natural radiation in the world. 226Ra existing in high concentrations in the soil of this region is washed by underground water and transferred to the surface. In this way, 226Ra enters the food chain of residents and substitutes within the hard body tissues of humans. 226Ra is one of the so-called bone seekers as its metabolic processes in the human body are similar to calcium and remains in hard tissues of body because of its long half-life, and being an alpha emitter causes dangerous effects on human health. The purpose of this study is to determine the concentration of 226Ra in the teeth of residents of these high-level natural radiation areas, compared with a control group. Thirteen teeth in five groups were studied as the case group and thirteen teeth in five corresponding control groups were inspected. The mean values of the activity of 226Ra in the case group and in the control group were 0.32 and 0.18mBqg(-1), respectively.     

Effects of Soil Conditions on Survival and Growth of Black Willow Cuttings

Current streambank restoration efforts focus on providing bank stability, enhancing water quality, and improving woody habitat using native vegetation rather than traditional engineering techniques. However, in most cases harsh site conditions limit restoration success. A two-year field study was conducted at Twentymile Creek, in northern Mississippi, investigating edaphic factors governing the survival of black willow (Salix nigra) cuttings used for streambank restoration. Low height growth, above-ground biomass production, and average leaf area were observed in willow cuttings grown in plots subjected to moisture deficits. However, sediment texture emerged as the dominant factor determining willow post growth, health, and survival. Shoot biomass, leaf biomass, and total above-ground biomass were 15-, 10-, and 14-fold greater for large willow cuttings (posts) grown in plots with sandy sediments relative to those grown in plots with similar moisture and soil redox potential but with silt and clay sediments. Average leaf size, average leaf mass and specific leaf area were all lower in fine textured plots. Under moisture conditions present at our sites, coarse-grained sediment (sand) was more conducive to willow growth, biomass production, and survival than were fine-grained sediments (silt/clay). Our results strongly suggest that soil texture and moisture conditions can determine restoration success. Therefore, it is critical that site conditions are factored into the selection of project locations prior to the initiation of willow planting restoration projects.     

Viability of combining microalgae and macroalgae cultures for treating anaerobically digested piggery effluent

Algal phytoremediation represents a practical green solution for treating anaerobically digested piggery effluent(ADPE). The potential and viability of combining microalgae and macroalgae cultivation for the efficient treatment of ADPE were evaluated in this study.Bioprospecting the ability of different locally isolated macroalgae species illustrated the potential of Cladophora sp. to successfully grow and treat ADPE with up to 150 mg/L NH_4~+ with a biomass productivity of(0.13 ± 0.02) g/(L·day) and ammonium removal rate of(10.23 ± 0.18) mg/(L·day) NH_4~+. When grown by itself, the microalgae consortium used in this study consisting of Chlorella sp. and Scenedesmus sp. was found to grow and treat undiluted ADPE(up to 525 mg/L NH_4~+) with an average ammonium removal rate of 25 mg/(L·day) NH_4~+ and biomass productivity of(0.012 ± 0.0001) g/(L·day). Nevertheless, when combined together, despite the different cultivation systems(attached and non-attached) evaluated,microalgae and macroalgae were unable to co-exist together and treat ADPE as their respective growth were inversely related to each other due to direct competition for nutrients and available resources as well as the negative physical interaction between both algal groups.     

A comprehensive review of heavy metal pollution in the coastal areas of Bangladesh: abundance,bioaccumulation, health implications,and challenges

Environmental Science and Pollution Research - The coastal zone of Bangladesh, with a population density of 1278 people per square kilometer, is under serious threat due to heavy metal pollution....     

Numerical study of scouring downstream of a stilling basin

Environmental Fluid Mechanics - The aim of the present study is to numerically investigate the scouring phenomenon downstream of a stilling basin for a wide range of Froude number and size of bed...     

Investigating green roofs’ CO2 sequestration with cold- and drought-tolerant plants (a short- and long-term carbon footprint view)

Environmental Science and Pollution Research - In recent years, green roofs have become the subject of increasing interest because of their good aesthetic qualities, energy conservation, and...     

Environmental geochemistry of higher radioactivity in a transboundary Himalayan river sediment (Brahmaputra,Bangladesh): potential radiation exposure and health risks

Environmental Science and Pollution Research - This study of a downstream segment (Brahmaputra, Bangladesh) of one of the longest transboundary (China-India-Bangladesh) Himalayan rivers reveals...     

Adsorptive removal of ibuprofen to binary and amine-functionalized UiO-66 in the aquatic environment: synergistic/antagonistic evaluation

Environmental Science and Pollution Research - The removal of ibuprofen (IBP) from the aqueous solution by metal–organic frameworks such as UiO-66, UiO-66-NH2, and a binary MOF...