Shin-ichi Yamasaki

Waste ashes for use in agricultural production: I. Liming effect, contents of plant nutrients and chemical characteristics of some metals

The chemical characteristics of 89 municipal waste ashes, including food scrap ash (FSA), animal waste ash (AWA), horticulture waste ash (HWA), sewage sludge ash (SSA) and incinerator bottom ash (IBA), from various locations in Japan were examined with the aim of evaluating their suitability for use in agriculture. Although the waste ashes came from different sources and consisted of various materials, the gross elemental composition was similar. Acid neutralization capacity (liming effect) for the waste ashes was equivalent to 10-30% of CaO and followed the sequence SSA > IBA > AWA > FSA > HWA. Average P concentrations for the five types of waste ashes ranged from 10 to 29 g kg(-1) and average K concentrations ranged from 14 to 63 g kg(-1), respectively. Metal contents in the waste ashes were compared with levels in Japanese agricultural soils. K in the waste ashes was 1.3-6 times higher and Ca was 3-12 times higher; contents of the other metals in FSA, AWA and HWA were generally less than five times higher, but Ni, Cu, Zn, Cd, Sn, Pb in SSA or IBA were approximately 10-200 times higher than those in soils. Moreover, the ceiling amounts of waste ashes that may be applied to main Japanese agricultural soils were calculated by using soil contamination standards for Cu. Water solubility of P and metals in the waste ashes were also examined.

Accurate root length measurement by image analysis

Algorithms for estimating root length by image analysis should lead to results that have no systematic error (bias), be insensitive to preferential root orientation, valid across a wide range of sample sizes and adjust for overlap between roots in samples, to reduce the effort needed in spreading out root systems. We propose a new algorithm that forms a compromise between small bias and robustness (insensitivity to variation in sample size and preferential root orientation), and provide a simple way of dealing with root overlap. Image analysis was performed on a Macintosh computer using the public domain NIH Image program. The digital image of the root was processed to get the thinned image (skeleton). The numbers of orthogonally and diagonally connected pairs of pixels (No and Nd, respectively) in the skeleton were counted separately and used for length (L) calculation. A new length calculation equation was introduced so that the effect of orientation on length calculation was minimized; L=[Nd2+(Nd+No/2)2]1/2+No/2. The maximum error due to orientation of a single line was evaluated for an ideal line, and the analysis revealed that the new equation was less affected by orientation than previous equations. Copper wire and rice (Oryza sativa L.) roots containing both primary and fine secondary root were measured manually and with image analysis. The two methods showed good agreement within 1.5%. The proposed image analysis method yielded length estimates with CV from 0.23 to 0.88%, which was lower than the CVs of the line-intersect method. Moreover, the lengths of overlapping samples were calculated correctly because the image analysis method distinguished an overlapping pixel from a thinned image, while the calculation with the line-intersect method showed underestimation because overlaps were not considered in that method.

Rice uptake and distributions of radioactive 137Cs, stable 133Cs and K from soil

The distributions of radionuclides in plant components as to radionuclide transfer to animals are important for understanding the dynamics of radionuclides in an agricultural field. Most of the non-edible parts in these components are returned to the soil as organic fertilizer where they may again be utilized in the soil-plant pathway and/or are mixed with feed for livestock. Rice plants were grown in an experimental field and separated at harvest into different components, including polished rice, rice bran, hull, leaves, stem and root, and then the distributions of radioactive 137Cs, stable 133Cs and K in these components were determined. The distribution of 137Cs in polished rice and rice bran was similar to that of 133Cs, while that of K was different. The concentration ratios of 133Cs/K in leaf blade positions increased with aging, which means that the translocation rate of 133Cs in rice plants was slower than that of K. At harvest the distribution of dry weight in polished rice to entire rice plants was 34%, and the distributions of 133Cs in the polished rice and the non-edible parts were 7 and 93%, respectively, whereas those of K in the polished rice and the non-edible parts were 2 and 98%, respectively. Findings suggest that the transfer and distribution of 133Cs, not of K, provide better information on the long-term fate of 137Cs in an agricultural environment.

Background levels of trace and ultra-trace elements in soils of Japan

Abstract Five hundred and fourteen soil samples collected from 78 sites in Japan were analyzed for their contents of trace and ultra-trace elements. We estimated the background levels (natural abundance) of 57 elements in soils. The concentration ranges were so wide that the ratios of the highest values to the lowest values were more than 100 for all the elements, with the exception of Be, Ga, Mo, Ag, In, Sn, and Ba. While the concentrations of the first transition elements (21Sc to 30Zn in atomic numbers) were higher than the concentration of the other elements, those of lighter (3Li and 4Be) and heavier elements tended to decrease, with an increase or decrease of atomic numbers, with the apparent exception of Pb, Th, and U. Concentrations of elements with even atomic numbers were, in most of the cases, higher than the concentrations of both adjacent elements with odd atomic numbers. Frequency distribution of most of the elements was strongly positively skewed. Markedly positive correlation coefficients (r>0.9) were observed among the elements within the same group in the Periodic Table in many combinations. The dendrogram obtained by cluster analysis showed that the occurrence and distribution of the elements in soils were mostly controlled by the chemical properties of each element, rather than by the nature and properties of individual soil samples. The total contents of the elements in soils were strongly dependent on the chemical composition of the parent rocks from which respective soils were derived.

Application of a high resolution inductively coupled plasma mass spectrometer to the measurement of long-lived radionuclides

Some long-lived radionuclides, such as 99Tc, 226Ra, 232Th, 237Np, 238U, 239Pu and 240Pu were measured using high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). By using HR-ICP-MS with an ultrasonic nebulizer, the detection limits of these nuclides were 0.002–0.02 pg ml–1 and the sensitivities were 10 times better than those obtained using HR-ICP-MS without the ultrasonic nebulizer. More accurate isotopic data were also obtained using HR-ICP-MS than with quadrupole ICP-MS at lower concentrations of the analyte because of the improvement in counting statistics that can be obtained with HR-ICP-MS due to the greater efficiency of ion transmission. A comparison of the measurement of the 240Pu to 239Pu ratio is shown.

Application of waste ashes to agricultural land--effect of incineration temperature on chemical characteristics.

Incineration is one of the most important methods of municipal waste disposal. During incineration, various reactions of composition and decomposition may occur; the physical and chemical properties of municipal wastes may change to a great extent. In the present study, 15 samples, including food scraps (FS), animal wastes (AW) and sewage sludges (SS) were collected from various places in Japan, incineration treatments at 500 degrees C, 850 degrees C and 1000 degrees C were conducted in laboratory, and pH, EC, P content, various P forms, anions and soluble metals were determined. The results indicated that average pH increased by 1.09, 1.84, 2.27 and EC decreased by 4.6, 4.6, 5.6 ds m(-1) at 500 degrees C, 850 degrees C, 1000 degrees C, respectively, pH increased in the sequence of AM > SS > FS, and the decrease rate of EC was in the order of FS > SS > AM. Compared with no treatment (NT), water-soluble P decreased greatly at all three temperatures; available P increased at 500 degrees C, but decreased to the original level at 850 degrees C and 1000 degrees C; the amount of Ca-P, Fe-P and Al-P decreased and residual insoluble P increased greatly at 850 degrees C and 1000 degrees C; no significant change of total P was found at all three temperatures. However, water-soluble HPO4(2-) and Cl- decreased greatly, the decrease ratio of Cl- was in the sequence of SS > FS > AM at 500 degrees C, and FS > SS > AM at 850 degrees C and 1000 degrees C; no significant difference was found for HPO4(2-) among all three treatment temperatures; water-soluble SO4(2-) decreased at 1000 degrees C, but there was no significant change at 500 degrees C and 850 degrees C. Moreover, water-soluble Na, Mg, K, Ti, Mn, Fe, Ga, Cd, Zn, Ba, Pb, Sr, W and 0.1 M HNO3 soluble Al, K, Cr, Mn, Fe, Zn, Sr, Ba, Pb, Be, Ga, Rb, Cd, Sn, Sb, Ta, Tl, Bi, Na, Co, Ni, Sc, Cs decreased, but water-soluble Ca, Cr, Co, Ni and 0.1 M HNO3 soluble Cu, Ca, V, Mo, W, Th, U, Hf increased at 500 degrees C, 850 degrees C or 1000 degrees C.

Waste ashes for use in agricultural production: II. Contents of minor and trace metals

The present study was carried out to examine the contents of 18 minor and trace metals in five typical municipal waste ashes in Japan. In the waste ashes, Li, Ga, Rb, Y, Zr had relatively higher concentrations, approximately 5-300 mg kg(-1), the remaining metal concentrations were generally approximately 0.05-20 mg kg(-1). A comparison of the metal concentrations in the waste ashes and in Japanese agricultural soils indicated that the ratios for Ga, Mo, Ag, Sb, W, Bi between sewage sludge ash (SSA) and the soils were approximately 10-100 and for the remaining metals approximately 0.2-2; the ratios between food scrap ash (FSA), animal waste ash (AWA), horticulture waste ash (HWA) and incinerator bottom ash (IBA) and the soils were approximately 0.2-5. Furthermore, an overall evaluation on the waste ashes was also carried out using factor analysis with the addition of the other 21 elements examined in a companion paper. In the waste ashes, the major nutrient elements and heavy metals were mainly described by four factors: factors 1 and 2 explained the main information of the minor and trace metals while factors 3 and 4 explained that of the major nutrient elements. Factor 2 in the score plots could be used to evaluate the potential risk of the waste ashes to agricultural soils. Of the five types of waste ashes, SSA and IBA were abundant with minor and trace metals; AWA was relatively abundant with major nutrient elements especially for K; FSA was relatively abundant with major nutrient elements except for K, while HWA was not abundant with either of them.

Rare earth element and clay minerals of paddy soils from the central region of the Mekong River, Laos

Abstract The rare earth elements (REE) content, particle-size distribution, and clay mineralogical composition were analyzed for the paddy soils collected from the central region of the Mekong River, Laos, to study the origin and inherent potentiality of soils. REE as the chondrite-normalized curve of the plot of Ce/Eu against Eu/Sm were found to be useful for grouping soils according to their origins. The soils in the upper area (Luang Prabang Province, approximate elevation 300–400 m) were estimated to originate from the composite materials of the sediment derived from local granite and limestone and the sediment transported by the Mekong River. The predominant clay mineral was mica and its weathering product or kaolins, and the mineralogical composition varied from site to site. The soils were generally characterized by high clay and silt contents. Inherent potentiality was evaluated to be of intermediate to high level. The soils in the lower area (Vientiane Prefecture and Borikhamxay Province, approximate elevation 90–150 m) were estimated to originate from sediment transported by the Mekong River or from sediment derived from local sandstone. The soils originating from the Mekong River sediment were medium-textured and mica-dominated and were evaluated to be at the intermediate level of inherent potentiality. The soil originating from the sediment of local sandstone was coarse-textured and contained mica and kaolinite as the predominant clay minerals. Its inherent potentiality was evaluated to be poor.

Determination of total contents of bromine, iodine and several trace elements in soil by polarizing energy-dispersive X-ray fluorescence spectrometry

A non-destructive analysis method for total bromine (Br) and iodine (I) contents in soil was established using polarizing energy-dispersive X-ray fluorescence (EDXRF) spectrometry. The matrix-corrected intensity of Br and I Kα X-rays from pressed pellets of soil powder samples was calibrated with their contents measured by inductively coupled plasma (ICP)-mass spectrometry after pyrohydrolysis preparation. The calibration curves for Br and I were successfully obtained in the concentration ranges 3.8–223 mg kg−1 and 0.91–54 mg kg−1 respectively. Repeated analyses of the same sample with polarizing EDXRF spectrometry within one day and after approximately 1.5 years showed good reproducibility of the measurement results. The lower limits of detection for Br and I were 0.14 mg kg−1and 0.34 mg kg−1 respectively. The established analytical method for total Br and I contents in soil is non-destructive, simple and rapid, and is suitable for routine analysis. Trace elements such as rubidium (Rb), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), cadmium (Cd), tin (Sn), antimony (Sb), caesium (Cs), barium (Ba), light rare earth elements and lead (Pb) were also measurable simultaneously under the identical operational conditions as those for Br and I measurements.

Evaluation of cadmium and other metal losses from various municipal wastes during incineration disposal

The Japanese intake much more Cd through food than people in other countries, this may be partly caused by the activity of municipal waste incineration disposal. The present study was carried out to examine the behavior of Cd and to identify the other lost metals during municipal waste incineration. Thirty-eight waste samples, including food scraps (FS), animal wastes (AW), horticulture wastes (HW) and sewage sludges (SS) were collected from various places in Japan. Treatment temperatures of 500, 850, and 1000 degrees C were conducted to these samples in laboratory, and thirty-nine kinds of metals were examined. The results showed that average Cd losses were 69% (2.4 mg kg-1) and 74% (2.6 mg kg-1) at 850 and 1000 degrees C, respectively. Furthermore, the losses of 20 other metals were also found, i.e. Sn lost at 500 degrees C, K, Mg, Na, Bi, Cr, Ge, Li, Pb, Sn, Tl, Zn lost at 850 degrees C, and nine more metals, Al, Be, Cs, Nb, Sb, Sr, Th, Y, Zr lost at 1000 degrees C. The lost metals were considered to be transferred into the combustion flue gas, mainly in the forms of metallic chloride compounds, e.g. CdCl2, SnCl4, SnCl2, ZnCl2, PbCl2, etc. On the other hand, no significant losses for Ca, Fe, Ag, Ba, Co, Cu, Ga, Hf, Mn, Mo, Ni, Rb, Sc, Ta, Ti, U, V, W were found at 0.05 probability level. Total metal losses could be calculated at 9.9 and 20 g kg-1, in which major metal (Al, K, Mg, Na) losses were 9.5, 19 g kg-1 and minor and trace metal losses were 0.4, 0.6 g kg-1 at 850 and 1000 degrees C, respectively. Among the four types of waste materials, Cd losses were 0.8-3.7 mg kg-1, occupied about 60-80% at 850 degrees C, and 0.9-3.9 mg kg-1, occupied about 65-85% at 1000 degrees C. The total major metal losses from the four types of waste materials could be calculated at 6.5-15 g kg-1 at 850 degrees C, and 11-31 g kg-1 at 1000 degrees C, minor and trace metal losses were 0.03-1.3 g kg-1 at 850 degrees C, and 0.3-1.5 g kg-1 at 1000 degrees C, respectively.