Total effective dose equivalent assessment after exposure to high-level natural radiation using the RESRAD code

The current work reports the activity concentrations of several natural radionuclides (²²⁶Ra, ²³²Th, and ⁴⁰K) in Khak-Sefid area of Ramsar, Iran. An evaluation of total effective dose equivalent (TEDE) from exposure to high-level natural radiations is also presented. Soil samples were analyzed using a high-purity germanium detector with 80 % relative efficiency. The TEDE was calculated on a land area of 40,000 m² with 1.5-m thickness of contaminated zone for the member of three critical groups of farmer, construction worker, and resident using Residual Radioactive Material Guidelines (RESRAD) modeling program. It was found that the mean activity concentrations (in Bq/kg) were 23,118?±?468, 25.8?±?2.3, and 402.6?±?16.5 for ²²⁶Ra, ²³²Th, and ⁴⁰K, respectively. The maximum calculated TEDE during 1,000 years was 107.1 mSv/year at year 90, 92.42 mSv/year at year 88, and 22.09 mSv/year at year 46 for farmer, resident, and construction worker scenarios, respectively. The maximum TEDE in farmer scenario can be reduced to the level below the dose limit of 1 mSv/year which is safe for public health using soil cover with thickness of 50 cm or more on the contaminated zone. According to RESRAD prediction, the TEDE received by individuals for all exposure scenarios considerably exceed the set dose limit, and it is mainly due to ²²⁶Ra.     

Multimedia environmental monitoring: 50 years at Hanford

Environmental monitoring has been an ongoing activity on the U.S. Department of Energy's Hanford Site in southeastern Washington for almost 50 years. Objectives are to detect and assess potential impacts of Site operations on air, surface and ground waters, foodstuffs, fish, wildlife, soil and vegetation. Data from monitoring effects are used to calculate the overall radiological dose to humans working onsite or residing in nearby communities. In 1989, measured Hanford Site perimeter concentrations of airborne radionuclides were below applicable guidelines. Concentrations of radionuclides and nonradiological water quality in the Columbia River were in compliance with applicable standards. Foodstuffs irrigated with river water taken downstream of the Site showed radionuclide levels that were similar to those found in foodstuffs from control areas. Low levels of ¹³⁷Cs and ⁹⁰Sr in most onsite wildlife samples and concentrations of radionuclides in soils and vegetation from on- and offsite locations were typical of those attributable to worldwide fallout. The calculated dose potentially received by a maximally exposed individual (i.e., based on hypothetical, worst-case assumptions for all routes of exposure) in 1989 (0.05 mrem/yr) was similar to those calculated for 1985 through 1988.In addition to monitoring radioactivity in fish and wildlife, population numbers of key species are determined. Chinook salmon (Oncorhynchus tshawytscha) spawning in the Columbia River at Hanford has increased in recent years with a concomitant increase in winter roosting activity of bald eagles (Haliaeetus leucocephalus). An elk (Cervus elaphus) herd, established by immigration in 1972, is also increasing. The Hanford Site currently serves as a refuge for Canada goose (Branta canadensis), great blue heron (Ardea herodias), and various plants and other animals, e.g., mule deer (Odocoileus hemionus), and coyotes (Canis latrans).     

210-Polonium studies in some environmental and biological matrices of Domiasiat uranium deposit area, West Khasi Hills, Meghalaya, India

The study was performed using a silicon surface barrier alpha spectrometer at Bhabha Atomic Research Centre, Mumbai, India. Through the study, the observed ²¹⁰Po activity in water sample from different locations in the Domiasiat area ranges from 0.04 to 0.69 Bq/l. The daily and annual intake of ²¹⁰Po through water was also estimated and the mean value of 0.72 and 263.61 Bq, respectively, were observed. It is observed that the effective doses through water were higher than the World Health Organization recommended dose of 0.05 mSv/year. The total annual effective doses through terrestrial ingestion for all the locations was studied and the mean annual effective dose was observed to be 0.315 mSv, which, when compared to the worldwide and the Indian values, was observed to be slightly higher. The mean activity in soil is found to be 124.8 ±5.7 Bq/kg and in meat the activity is 0.43 ±0.05 Bq/kg. In fishes, an activity of 0.48 ±0.07 Bq/kg in Garra lamta, 0.29 ±0.02 Bq/kg in Neolissocheilus hexaganolepis, and 3.3 ±0.1 Bq/kg in Macrobrachium sp. is observed. Activity concentration in plant samples was analyzed and the activity ranges from 0.020 ±0.002 to 9.69 ±0.35 Bq/kg. Committed effective dose by the adult population of the Domiasiat area through intake of ²¹⁰Po through these food items was also determined and compared with the Indian average value and the worldwide average value.     

Parameter uncertainty and sensitivity in a liquid-effluent dose model

Radioactive materials which are released into streams on the Savannah River Site (SRS) eventually flow into the Savannah River. Tritium, ⁹⁰Sr, ¹³⁷Cs, and ²³⁹Pu account for the majority of the radiation dose received by users of the Savannah River. This paper focuses on the dose uncertainties originating from variability in parameters describing the transport and uptake of these nuclides. Parameter sensitivity has also been determined for each liquid pathway exposure model. The models used here to estimate radiation dose to an exposed individual provide a range of possible dose estimates that span approximately one order of magnitude. A pathway analysis reveals that aquatic food and water consumption account for more than 95% of the total dose to an individual.     

An appraisal of subsurface geology and groundwater resources of Owerri and environs based on electrical resistivity survey and borehole data evaluation

The research was aimed at determining the depth to the watertable, aquifer thickness and subsurface geology of the studyarea thus revealing its groundwater distribution as well as its potential as a substitute to the surface water resources.Vertical electrical soundings were carried out in the study area with maximum electrode spread. The Schlumberger electrode configuration technique was adopted. VES data were processedusing Schlumberger analysis package. Lithologic logs of alreadyexisting boreholes in the study area were collected, evaluatedand comparison were carried out. The results reveal alternatinglayers of sands, sandstones, gravel and clay. The lithologiclogs revealed that the study area is underlain by coastal sands (Benin formation). The water table varies from 10–64 m and thickness of the aquifer ranges from 20–80 m. Results show that the study area is underlain by a thick extensive aquifer that has a transmissivity of 2.8 × 10^-2m² s^-1 to 3.3 × 10^-1m² s^-1 and storativity 1.44 × 10^-4 to 1.68 × 10^-3m s^-1 values. The specific yield is about 0.31.The sandy component of the study area forms more than 90% ofthe sequence, therefore the permeability, the transmissivity andthe storage coefficient are high with an excellent source of groundwater resources.     

The prevalence of bacterial resistance in clinical, food, water and some environmental samples in Southwest Nigeria

The resistance pattern and mechanisms of bacterial isolates obtained from clinical origin, soil, industrial effluent, orange juice products and drinking water were studied using commonly used antibiotics. The microbial load of the water samples, industrial effluent and orange juice products were 1.0 × 10¹–2.25 × 10⁶, 2.15 × 10⁵, and 3.5 × 10⁴–2.15 × 10⁵ cfu mL^–1, respectively. The faecal coliform test revealed that only two out of twenty orange juice products had MPN of 2 and 20, the MPN of water ranged from 1–1800, while the effluent had MPN of 1800. The bacterial isolates that were isolated include E. coli, S. aureus, P. vulgaris, S. marcescens, S. pyogenes, B. cereus, B. subtilis, Micrococcus sp., Klebsiella sp., P. aeruginosa, and Enterobacter sp. Also, clinical and soil isolates of P. aeruginosa were used in the study. Among the eight antibiotics tested for resistance on five strains of each bacterium, seven different resistance patterns were observed among the bacterial isolates obtained from water, effluent and orange juice products. Among the clinical and soil isolates of P. aeruginosa, four multiple-drug resistance patterns were obtained. Thirty strains of E. coli and S. aureus were tested for -lactamase production and fourteen strains, seven each of E. coli and S. aureus that had high Minimum Inhibitory Concentration values (MIC) for both Amoxycillin and Cloxacillin were positive.     

Radionuclide Concentrations in Benthic Invertebrates from Amchitka and Kiska Islands in the Aleutian Chain, Alaska

Concentrations of 13 radionuclides (¹³⁷Cs, ¹²⁹I, ⁶⁰Co, ¹⁵²Eu, ⁹⁰Sr, ⁹⁹Tc, ²⁴¹Am, ²³⁸Pu, ^239,249Pu, ²³⁴U, ²³⁵U, ²³⁶U, ²³⁸U were examined in seven species of invertebrates from Amchitka and Kiska Islands, in the Aleutian Chain of Alaska, using gamma spectroscopy, inductively coupled plasma mass spectroscopy, and alpha spectroscopy. Amchitka Island was the site of three underground nuclear test (1965–1971), and we tested the null hypotheses that there were no differences in radionuclide concentrations between Amchitka and the reference site (Kiska) and there were no differences among species. The only radionuclides where composite samples were above the Minimum Detectable Activity (MDA) were ¹³⁷Cs, ²⁴¹Am, ^239,249Pu, ²³⁴U, ²³⁵U, ²³⁶U, and ²³⁸U. Green sea urchin (Strongylocentrotus polyacanthus), giant chiton (Cryptochiton stelleri), plate limpets (Tectura scutum) and giant Pacific octopus (Enteroctopus dofleini) were only tested for ¹³⁷Cs; octopus was the only species with detectable levels of ¹³⁷Cs (0.262 ± 0.029 Bq/kg, wet weight). Only rock jingle (Pododesmus macroschisma), blue mussel (Mytilus trossulus) and horse mussel (Modiolus modiolus) were analyzed for the actinides. There were no interspecific differences in ²⁴¹Am and ^239,240Pu, and almost no samples above the MDA for ²³⁸Pu and ²³⁶U. Horse mussels had significantly higher concentrations of ²³⁴U (0.844 ± 0.804 Bq/kg) and ²³⁸U (0.730 ± 0.646) than the other species (both isotopes are naturally occurring). There were no differences in actinide concentrations between Amchitka and Kiska. In general, radionuclides in invertebrates from Amchitka were similar to those from uncontaminated sites in the Northern Hemisphere, and below those from the contaminated Irish Sea. There is a clear research need for authors to report the concentrations of radionuclides by species, rather than simply as ‘shellfish’, for comparative purposes in determining geographical patterns, understanding possible effects, and for estimating risk to humans from consuming different biota.     

Interspecies comparison of lichens as biomonitors of trace-element air pollution

The linearity of the interspecies relation between the elemental contents in Parmelia sulcata and Lecanora conizaeoides, sampled in a polluted area, was examined by the function y=az+b and yz ^–1=a+bz ^–1, with y and z being the elemental content in Parmelia and Lecanora, respectively. For As, Co, V and Zn significant positive a and b values were found, allowing interspecies calibration. For Br, Cd, Cr, Fe, La, Sb, Se and W the a values were zero and the b values were positive, indicating saturation of Parmelia and thus ruling out interspecies calibration. For Cu a part of the data set showed saturation effects in Lecanora. The results showed that the average concentration ratio could not be used for intercalibration purposes, because the concentration ratios were dependent on the concentrations.     

Development of simple and sensitive spectrophotometric method for the determination of bendiocarb in its formulations and environmental samples

Facile, selective and sensitive spectrophotometric method has been developed for the determination of bendiocarb in its insecticidal formulations, fortified water, food grains, agriculture wastewater and agriculture soil samples with prepared reagents. The method was based on alkaline hydrolysis of the bendiocarb pesticide, and the resultant hydrolysis product of bendiocarb was coupled with 2,6-dibromo-4-methylaniline to give a yellow color product with λmaxof457 nmorcouplingwith2, 6−dibromo−4−nitroanilinetoproducearedcoloredproductwithλ_max of474~nmorcouplingwith2, 4, 6−tribromoanilinetoformorangeredcoloredproducthasaλ_max of465 nm.Underoptimalconditions, Beer'slawrangefor2, 6−dibromo−4−methylaniline(DBMA)wasfoundtobe0.6−−14.0~μgmL ^-1, 0.8−−10.0 μgmL ^-1 for2, 6−dibromo−4−nitroaniline(DBNA)and0.4−−10.0 μgmL ^-1 for2, 4, 6−tribromoaniline(TBA).Themolarabsorptivityofthecolorsystemswerefoundtobe4.126~×~10⁴ lmol ^-1 cm ^-1 forDBMA, 3.254×10⁴ l~mol ^-1 cm ^-1 forDBNAand2.812×10⁴ lmol ^-1 cm ^-1 forTBA.Sandell'softhecolorreactionsare0.018 μgcm ^-2(DBMA), 0.052 μgcm ^-2(DBNA)and0.065 μgcm ^-2$ (TBA) respectively. The effect of the non-target species on the determination of bendiocarb was studied. The formation of colored derivatives with the coupling agents is instantaneous and stable for 18 h, 30 h, and 12 h. Performance of the proposed methods were compared statistically in terms Student's F and t-tests with the reported methods.     

Simultaneous measurements of radon and thoron,and their progeny levels in dwellings on anticlinal structures of Assam,India

Radon and thoron, and their progeny concentrations along with equilibrium factors for gas progeny and radiological risks to the residents have been measured in dwellings of Digboi and Mashimpur areas located on anticlines during the winter season. In this present investigation, twin-cup dosemeters fitted with LR-115 (II) nuclear detectors have been employed. The present work has shown that there exist considerable house-to-house variations in values with maximum values in mud houses and minimum values in assam type (AT) houses. It has been found that mean (and geometric standard deviations (GSD)) radon concentrations are 83.8 (1.3), 113.5 (1.1) and 157.2 (1.2) Bq m^?3 in AT, reinforced cement concrete (RCC) and mud houses in Digboi area and 63.0 (1.1), 87.1 (1.4) and 182.1 (1.2) Bq m^?3 in AT, RCC and mud houses in Mashimpur area, respectively. The overall mean radon concentrations in Digboi and Mashimpur are estimated to be 114.4 (1.4) and 100.0 (1.7) Bq m^?3. The mean radon concentrations are found to be less than the lower reference level of 200 Bq m^?3 of the International Commission on Radiological Protection (ICRP 2007). The thoron concentrations in Digboi area are estimated to be 31.1 (1.3), 50.8 (1.4) and 67.0 (1.6) Bq m^?3 in AT, RCC and mud houses, respectively, whereas in Mashimpur area, the thoron concentrations are estimated to be 26.4 (1.3), 44.4 (1.3) and 77.7 (1.3) Bq m^?3 in AT, RCC and mud houses, respectively. The mean annual effective doses in Digboi area are found to be 1.9 (1.3), 2.7 (1.2) and 4.1 (1.4) mSv y^?1 in AT, RCC and mud houses, respectively, while in the case of Mashimpur area, the mean annual effective doses are found to be 1.5 (1.4), 2.2 (1.2) and 4.9 (1.3) mSv y^?1 in AT, RCC and mud houses, respectively. Nevertheless, the obtained results are much lower than the upper reference level of 10 mSv (ICRP 2007).     

顺序注射平台-分光光度法测定水中总磷

参照希思迪在线总磷分析仪和荷兰Skalar在线过程分析仪测定水中总磷的方法,对顺序注射平台分析技术进行改进,从而建立了钼酸铵分光光度法测定水中正磷酸盐的快速分析方法,该方法集微功耗、微量试剂消耗于一体。注射平台具有模块化、投入式探头等结构特征,仪器包含3个检测量程,适用于环境监测等领域的实时在线分析。实验选择磷酸蓝的测定吸收波长为880 nm,当总磷质量浓度为0.10~2.00 mg/L时,浓度与吸光度呈线性关系,线性回归方程y=0.970 3x-0.025 3,相关系数为0.999 5,方法的检出限为1.36×10-2mg/L。     

A forecast analysis on fertilizers consumption worldwide

This study aimed to make a review and forecast on fertilizers consumption worldwide in order to provide basal data for the decision-making of fertilizers production and for the environmental impact assessment of fertilizers application. It was found that fertilizers consumption was dependent on human population and the increase of fertilizers consumption was mainly resulted from expansion of human population. The univariate linear model, y=a+rx(t), where y is the fertilizers consumption, x(t) is the total human population at year t, r is the annual fertilizers consumption per capita, was used to fit historical data of fertilizers consumption, and the forecasts during 2010 to 2030 were given in detail. Model analysis showed that world’s per capita annual consumption of total fertilizers, nitrogenous fertilizers, phosphate fertilizers, and potash fertilizers, were 34.6, 24.4, 6.6, and 3.7 kg, respectively. Per capita annual consumption of total fertilizers for Asia, Africa, Caribbean, Oceania, North & Central America, Europe, and South America were 38.8, 5.9, 6.8, 114.0, 62.9, −0.9, and 43.6 kg, respectively. Compared to the current level, the world’s total fertilizers consumption would reach 226,150,381 Mt by 2030, an increase of 32.1% against current level. Worldwide consumption of nitrogenous fertilizers, phosphate fertilizers, and potash fertilizers would reach 141,800,601, 50,961,129, and 33,388,650 Mt by 2030, increasing 37.5, 25.8, and 21.2% based on current levels. Consumption of total, nitrogenous, phosphate, and potash fertilizers in Asia and Africa would increase 54 to 55% and 40 to 60% by 2030, respectively. Total fertilizers consumption in North & Central America would see an increase of 39.4% by 2030, and in South America and Oceania it would increase by 30.9 and 64.7%, respectively. By 2030, Caribbean’s consumption for total fertilizers would increase 2.8%. Europe’s total fertilizers consumption was forecast to continuously decline and would have a decrease of 2.4% by 2030. Annual relative growths of consumption of total fertilizers, nitrogenous fertilizers, phosphate fertilizers, and potash fertilizers for the world, Africa, Asia, and South America were forecast to decrease in the forecast period. For North & Central America, annual relative growths of consumption of total fertilizers and nitrogenous fertilizers would decrease and the others would increase annually by 2030. Annual relative growths of consumption of total fertilizers, phosphate fertilizers, and potash fertilizers for Oceania were forecast to rise annually by 2030. Europe’s annual relative growths of consumption of total fertilizers and potash fertilizers would decrease in the future.     

溪源水库蓄水前后冬春季水体营养盐和浮游植物特征研究

于2007—2008年溪源水库蓄水前,2014—2015年溪源水库蓄水后对溪源宫水源地水体进行采样,分析了冬春季水体的理化指标、浮游植物生物量及群落组成。蓄水前共鉴定出浮游植物6门26属43种,水体水质状况较好,浮游植物细胞密度平均为7.31×10~5cells/L,以硅藻、绿藻门为优势门类,两者占浮游植物总生物量的比例约为54.7%、32.2%,水体呈贫-中营养状态。蓄水后,水体氮、磷营养盐浓度分别约为蓄水前的2.4倍、3倍,浮游植物细胞密度平均为1.42×10~7cells/L,约为蓄水前的20倍,且群落结构发生改变,优势门类为硅藻、蓝藻、绿藻,所占比例分别为40.2%、38.7%、14.4%,蓝藻门比例有显著提高,约为蓄水前的5倍。说明建库蓄水对浮游植物的影响显著。     

Measurement of soil radioactivity levels and radiation hazard assessment in southern Rechna interfluvial region, Pakistan

Rechna interfluvial region is one of the main regions of Punjab, Pakistan. It is the area which is lying between River Ravi and River Chenab, alluvial-filled. Radioactivity levels in soil samples, collected from southern Rechna interfluvial region, Pakistan, have been estimated by using gamma-ray spectrometric technique. ²²⁶Ra, ²³²Th, the primordial radionuclide ⁴⁰K, and the artificial radionuclide ¹³⁷Cs have been measured in the soil of the study area. The mean radioactivity levels of ²²⁶Ra, ²³²Th, ⁴⁰K, and ¹³⁷Cs were found to be 50.6 ± 1.7, 62.3 ± 3.2, 662.2 ± 32.1, and 3.1 ± 0.3 Bq kg^???1, respectively. The mean radium equivalent activity (Ra_eq), outdoor radiation hazard index (H _out), indoor radiation hazard index (H _in), and terrestrial absorbed dose rate for the area under study were determined as 190.8 ± 8.7 Bq kg^???1, 0.52, 0.65, and 69.8 nGy h^???1, respectively. The annual effective dose to the general public was found to be 0.43 mSv. This value lies well below the limit of 1 mSv for general public as recommended by the International Commission on Radiological Protection. The measured values are comparable with other global radioactivity measurements and are found to be safe for the public and the environment.     

Anthropogenic plutonium in the North Jiangsu tidal flats of the Yellow Sea in China

The ^239+240Pu activities and ²⁴⁰Pu/²³⁹Pu atom ratios were analyzed using a double-focusing SF-ICP-MS for sediment core samples obtained in 2007–2008 from the North Jiangsu tidal flats in the Yellow Sea in China. Particular attention was focused on the ²⁴⁰Pu/²³⁹Pu atom ratios in the sediment to identify the origins of Pu isotopes. The profiles of ^239+240Pu activities in the sediment cores are similar to those of the ¹³⁷Cs activities. The ²⁴⁰Pu/²³⁹Pu atom ratios in the tidal flats showed typical global fallout values, indicating that this area did not receive the possible early direct close-in fallout or oceanic current transported Pu from the Pacific Proving Grounds (PPG). If any, the contribution of the PPG source Pu to the total Pu inventory is negligible. This is different from the sediments in the Yangtze River estuary in the East China Sea, where the PPG source Pu contributed ca. 45 % to the total inventory. In addition, the observation of the global fallout origin Pu in the North Jiangsu tidal flats indicated that the nuclear power plant in the region was not causing any alteration/contamination to the ²⁴⁰Pu/²³⁹Pu atom ratios. The ^239+240Pu and ¹³⁷Cs activities/inventories in the sediment cores showed correlation to the mean clay sediment compositions (fine particles) in the tidal flats. Therefore, mud deposits are served as sinks for the anthropogenic radionuclides in the tidal flats and the Yellow Sea. Integrated with the previously reported spatial distributions of ^239+240Pu and ¹³⁷Cs activities in the surface sediments of the Yellow Sea, the mechanism of Pu transport with the ocean currents and the scavenging characteristics in the Yellow Sea were discussed.     

Spectrophotometric determination of indiumin zinc effluent

A new extraction-spectrophotometric method for the determination of indium at ppb level in zinc effluent is described. It is based on quantitative extraction (51.2–99.2%) of the tetrabromoindate complex with toluene solution of N,N-diphenylbenzamidine and its nine analogous from sulphuric acid solutions, which allowed the extract to react with basic dye (i.e. brilliant green, malachite green, crystal violet) solution in sequence. Among the basic dyes tested, brilliant green gave the most sensitive colour reaction. The value of molar absorptivity of the amidine bromoindate extracts with brilliant green lie in the range of (0.53–1.03)×10⁵ l mole^-1 cm^-1 at absorption maximum, 630–640. With the most sensitive compound, N-(2-methyl-phenyl)-N-phenylbenzamidine(APPBA), the detection limit of the method is 13 ppb. The method is free from interferences of almost all ions associated with indium. The method has been applied for the determination of indium to zinc-effluent.     

Rate-Limited Desorption of Volatile Organic Compounds from Soils and Implications for the Remediation of a Louisiana Superfund Site

The rates of desorption of trichloroethylene (TCE) and 1,3-dichlorobenzene (DCB) from a silty soil at a Superfund site and a silty-clayey soil from an uncontaminated bottomland hardwoodswamp in Baton Rouge, Louisiana were studied in laboratory batchsystems. The effect of the age of soil contamination was studiedusing a laboratory-spiked soil incubated for 3 days, 3 months and5 months. An empirical non-linear model was used to describe thebi-phasic nature of desorption with one fraction (labile) beingreleased in relatively short periods of time (typically 24–100 hr) and a second fraction (non-labile or irreversible) beingresistant to desorption. The non-linear model parameters, viz.,the fraction of the chemical released rapidly (F), and the firstorder desorption rate coefficients, k ₁ and k ₂respectively for the labile and slowly released fractions weredetermined by fitting the experimental data to the model. Thedata fit the model well as indicated by the high r ² values.The estimate of k ₁ was good. However, the values of k ₂are known with less precision due to the limited duration of theexperiment and number of samples taken at long times. In addition, desorption kinetics of 3 and 5-month old contaminatedsoils showed that progressively less amount of contaminant was available for facile desorption (lower F) compared to freshly contaminated soil. The labile fraction had desorption rate constants of the order of 10^-1 h^-1, whereas the slowlyreleased fraction had rate constants of the order of 10^-4 h^-1 in accord with literature reported values for a varietyof other compounds and soils. Possible mechanisms describing these rates and implications for the site clean up are discussed.     

A study of background radioactivity level for Canakkale, Turkey

This study assesses the level of background radiation for Canakkale province of northwestern Turkey. Radon concentrations in indoor air were determined using CR-39 nuclear track detectors and ²²²Rn activity was found to be 167 Bq m^???3 (equivalent to an annual effective dose of 4.2 mSv). Measurements of outdoor gamma radiation (of terrestrial and cosmic origin) in air were performed using plastic scintillators, and the average absorbed gamma dose rate was found to be 66.4 nGy h^???1 (corresponding to an annual effective dose of 81.4 μSv). The radionuclide activity concentrations in soil samples collected from the study area were measured through gamma-ray spectrometry, and the average activities were determined as 94.55, 110.4, and 1,273 Bq kg^???1 for the natural radionuclides ²³⁸U, ²³²Th, and ⁴⁰K, respectively, and 19.39 Bq kg^???1 for the fission product ¹³⁷Cs. The natural radioactivity sources resulted in an annual effective dose of 184 μSv. The radioactivity levels of drinking water samples were measured as 0.0599 Bq l^???1 for gross-alpha activity and 0.0841 Bq l^???1 for gross-beta activity using a low-background counting technique (equivalent to an annual effective dose of 12.25 μSv). The results of this study show that the activity levels of radon in air, radionuclides in soil, and alpha activities in drinking water are higher compared to the data available for other Turkish cities and the world averages. On the other hand, the outdoor gamma dose rates in air and beta activities in drinking water are within natural limits.     

Persistence behaviour of imidacloprid and its metabolites in soil under sugarcane

The persistence and metabolism of imidacloprid in soil under sugarcane were studied following application of imidacloprid at 20 and 80 g active ingredient (a.i.) ha^?1. Soil samples were collected at different time intervals (7, 15, 30, 45, 60 and 90 days after application), and the residues of imidacloprid and its metabolites (6-chloronicotinic acid, nitrosimine, imidacloprid-NTG, olefin, urea and 5-hydroxy) were quantified by high-performance liquid chromatography. In soil, the total imidacloprid residues were mainly constituted by the parent compound followed by 6-chloronicotinic acid, nitrosimine and imidacloprid-NTG metabolites. Maximum residues of imidacloprid and its metabolites were 4.29 and 7.81 mg kg^?1 in soil samples collected 7 days after the application of imidacloprid at 20 and 80 g a.i. ha^?1, respectively. At both doses, these residues declined to below the detectable limit in soil after 90 days of application. Olefin, urea and 5-hydroxy metabolites were not detected in soil. Dissipation of total imidacloprid residues did not follow the first-order kinetics with a coefficient of determination value of 0.883 and 0.838 for the recommended dose and four times the recommended dose, respectively. The half-life (T _1/2) value of total imidacloprid was observed to be 10.64 and 10.10 days for the recommended dose and four times the recommended dose, respectively.     

Mesophilic biomethanation and treatment of poultry waste-water using pilot scale UASB reactor

The feasibility of applying the up-flow anaerobicsludge blanket (UASB) treatment for poultry waste (faeces)water was examined. A continuous-flow UASB pilot scalereactor of 3.50 L capacity using mixed culture was operatedfor 95 days to assess the treatability of poultry waste-water and its methane production. The maximum chemicaloxygen demand (COD) removed was found to be 78% whenorganic loading rate (OLR) was 2.9 kg COD m^-3 day^-1 athydraulic retention times (HRT) of 13.2 hr. The averagebiogas recovery was 0.26 m³ CH₄ kg COD with an averagemethane content of 57% at mean temperature of 30 °C.Data indicate more rapid methanogenesis with higher loadingrates and shorter hydraulic retention times. At feedconcentration of 4.8 kg COD m^-3 day^-1, anaerobic digestionwas severely retarded at all hydraulic retention timetested. This complication in the reactor operations may belinked to build-up of colloidal solids often associated withpoultry waste water and ammonia toxicity. Isolates fromgranular sludge and effluent were found to be facultativeanaerobes most of which were Pseudomonas genera.