An ethnoarchaeological study of chemical residues in the floors and soils of Q'eqchi' Maya houses at Las Pozas,Guatemala

This ethnoarchaeological study at the Q'eqchi' Maya village of Las Pozas, Guatemala, aimed to refine the understanding of the relationship between soil chemical signatures and human activities for archaeological applications. The research involved phosphorus, exchangeable ion (calcium, potassium, magnesium, sodium), and trace element analysis of soils and earth floors extracted by Mehlich II, ammonium acetate, and DTPA chelate solutions, respectively. The results showed high levels of phosphorus, potassium, magnesium, and pH in food preparation areas, as well as high phosphorus concentrations and low pH in food consumption areas. The traffic areas exhibited low phosphorus and trace element contents, whereas refuse disposal areas were enriched. These results provide important information for the understanding of space use in ancient settlements. © 2002 Wiley Periodicals, Inc.     

Chemical speciation and fate of tripolyphosphate after application to a calcareous soil

Adsorption and precipitation reactions often dictate the availability of phosphorus in soil environments. Tripolyphosphate (TPP) is considered a form of slow release P fertilizer in P limited soils, however, investigations of the chemical fate of TPP in soils are limited. It has been proposed that TPP rapidly hydrolyzes in the soil solution before adsorbing or precipitating with soil surfaces, but in model systems, TPP also adsorbs rapidly onto mineral surfaces. To study the adsorption behavior of TPP in calcareous soils, a short-term (48 h) TPP spike was performed under laboratory conditions. To determine the fate of TPP under field conditions, two different liquid TPP amendments were applied to a P limited subsurface field site via an in-ground injection system. Phosphorus speciation was assessed using X-ray absorption spectroscopy, total and labile extractable P, and X-ray diffraction. Adsorption of TPP to soil mineral surfaces was rapid (< 48 h) and persisted without fully hydrolyzing to ortho-P. Linear combination fitting of XAS data indicated that the distribution of adsorbed P was highest (~ 30–40%) throughout the site after the first TPP amendment application (high water volume and low TPP concentrations). In contrast, lower water volumes with more concentrated TPP resulted in lower relative fractions of adsorbed P (15–25%), but a significant increase in total P concentrations (~ 3000 mg P kg soil) and adsorbed P (60%) directly adjacent to the injection system. This demonstrates that TPP application increases the adsorbed P fraction of calcareous soils through rapid adsorption reactions with soil mineral surfaces.     

Midden formation and intrasite chemical patterning in Kalinga,Philippines

Middens are surprisingly fluid entities in occupied communities, as shown by ethnoarchaeological research in Dalupa, Kalinga Province, northern Luzon, the Philippines. This study combines ethnoarchaeological observations of midden formation and disturbance in Dalupa with data from soils and sediments in natural, habitation, and midden contexts, including elemental data for 80 samples collected using inductively coupled plasma‐atomic emission spectroscopy. Most surface samples from habitation areas cluster with midden samples, although samples from the lower parts of theses profiles resemble samples from natural contexts around Dalupa. One explanation is a changing spatial distribution of active middens due to changes in house placement and occupation in Dalupa's history. Some habitation areas that chemically resemble middens may once have held middens, as suggested by the periodic changes in midden location from the cleaning and management of extramural space. Surface scatters of human and animal refuse throughout the habitation area may also contribute to this pattern. © 2007 Wiley Periodicals, Inc.     

Levels and distribution of total nitrogen and total phosphorous in urban soils of Beijing, China

Urban soil nitrogen and phosphorus have significant implications for the soil and water quality in urban areas. The concentrations of total nitrogen (TN) and total phosphorus (TP) of soil samples collected from six types of land use, which included residential area (RA), business area (BA), classical garden (CG), culture and education area (CEA), public green space (PGS) and roadside area (RSA) of Beijing urban area, were investigated. Results showed that the geometric mean of TP (857 mg/kg) in urban soils was slightly higher than that (745 mg/kg) in rural soils of Beijing. The concentration of soil TP was higher in the center of the city, and showed an increasing trend with the age of the urban area. The TP concentrations in the six types of land use followed the sequence of CG > BA > RSA > RA > CEA > PGS, which were affected by the use and disposal of phosphorus-containing materials in each type of land use. However, the geometric mean of TN (753.8 mg/kg) in urban soils was much lower than that (1,933.3 mg/kg) in rural soils. TN level in urban soils of Beijing had no correlation with the city’s urbanization history, and was influenced by the coverage of natural vegetation and human activities in each type of land use. This study suggested that the city’s urbanization history and land use were the main factors affecting the distribution of nitrogen and phosphorus in urban soils.     

Comparison between inductively coupled plasma and X-ray fluorescence performance for Pb analysis in environmental soil samples

Comparison of two conventional analytical techniques such as X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) for measuring Pb concentrations in soil samples was achieved using field and laboratory work. Seventy-three samples were collected from urban areas surrounding the large lead smelter at South Australia, as an indicator of the environment impact of smelter activity. Soil Pb concentrations were determined using hand-held XRF analyser under laboratory conditions. ICP-MS analysis on digested soils (using a microwave-assisted nitric acid digestion-extraction) was applied to validate p-XRF data. The analysis showed that Pb concentrations determined by XRF correlated with high linearity with Pb concentrations determined by ICP-MS measurements (R ² = 0.89). Statistical test (t test) was applied to the data of both methods applied without any significant difference between the two techniques. These results indicated that ICP-MS corroborated XRF for Pb soil measurements and suggests that XRF was a reliable and quick alternative to traditional analytical methods in studies of environmental health risk assessment, allowing for much larger sampling regimes in relatively shorter times and could be applied in the field.     

Fractions and Bioavailability of Soil Inorganic Phosphorus in the Loess Plateau of China under Different Vegetations

Plants play an important role in soil phosphorus nutrition. However, the effect of plants on phosphorus nutrition in soils of the Loess Plateau of China is not well understood. This study was conducted to reveal the relationships between plants and phosphorus’ fractions and availability in the Loess Plateau of China. Twenty-two plant communities were surveyed and soil samples under different plant canopies were collected for the determination of soil properties and inorganic phosphorus fractionation. The results showed that Leguminosae and Lilaceae reduced pH and increased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies, while Labiatae and Rosaceae increased pH and decreased organic matter, cation exchange capacity, total and Olsen phosphorus in soils under their canopies. The contents of Ca2P, Ca8P, Al-P and Fe-P were highly related with soil Olsen phosphorus. They were all higher in soils under Leguminosae and Lilaceae and lower in soils under Labiatae and Rosaceae. The results of this study indicate that Leguminosae and Lilaceae improved phosphorus nutrition in soils, yet Labiatae and Rosaceae impeded the improvement of phosphorus nutrition in soils under their canopies, which will be of more help to instruct vegetation restoration in the region and provide information for soil development.     

Concentrations and solubility of heavy metals in muck sediments from the St. Lucie Estuary,U.S.A.

To evaluate muck sediments as a potential soil amendment, total and Mehlich III-extractable concentrations of Cd, Cu, Cr, Ni, Pb, Zn, and Co in 59 muck sediment samples from the St. Lucie Estuary were analyzed. A seven-step chemical fractionation procedure was used to assess the potential mobility of heavy metals. Except for Cd, the average total concentrations of the metals are lower than the reported average concentrations of these elements in municipal composts in the U.S.A. The concentrations were also below critical levels for the safe use of wastes and byproducts in agriculture, as established by the United States Environmental Protection Agency. The Cd, Cu, Cr, Ni, Pb, Zn and Co in the sediments were predominantly associated with silicate minerals in the residual form. Most metals in the muck sediments occur predominantly in weakly mobile or nonbioavailable forms. Use of mucks in neutral pH upland soils should not pose any significant hazards or risk to the environment. However, Cd, Cu, Cr, Ni, Pb, Zn, and Co, especially Zn, Cu, and Pb, could be more readily released from the muck sediments under acidic soil conditions.     

Correlations among hydrocarbon microseepage, soil chemistry, and uptake of micronutrients by plants, Bell Creek oil field, Montana

Chelate-extractable iron and manganese concentrations in soils over and around the Bell Creek oil field suggest that compared to low average background values, there are moderate amounts of these elements directly over the production area and higher concentrations distributed in an aureole pattern around the periphery of the field. Adsorbed and organically bound iron and manganese appear to be readily taken up by plants resulting in anomalously high levels of these elements in leaves and needles over the oil field and suggesting correlation with corresponding low concentrations in soils. Iron and manganese appear to have bypassed the soil formation process where, under normal oxidizing conditions, they would have ultimately precipitated as insoluble oxides and hydroxides.     

Using in‐field phosphate testing to rapidly identify middens at Piedras Negras,Guatemala

Recent studies have promoted using soil phosphate analysis to detect ancient Maya sites by delimiting areas of occupation based on decomposed organic matter. Refuse associated with human activity increases organic matter around areas of ancient human habitation. Theoretically, the highest concentration of organic matter—detectable by phosphate analysis—should be directly associated with areas of refuse disposal. Thus, the objective of this study is to investigate the potential of phosphate analysis to detect residential middens in Piedras Negras, Guatemala. This paper presents the results of a sensitive, in‐field phosphate analysis method applied as a midden prospection tool in residential areas. Phosphate concentration is correlated with artifact data obtained from a total of 37 test pits excavated in areas of varying phosphate concentration in three residential sites. A positive correlation between phosphate concentration and ceramic density indicates the potential of this method in defining and orienting excavations of residential areas. © 2001 John Wiley & Sons, Inc.     

Drinking water treatment residuals as an amendment to alkaline soils: Effects on the growth of corn and phosphorus extractability

Drinking water treatment residuals (alum) are waste products of water purification that have potential for environmental remediation as a soil amendment and a potential plant growth medium. In this study, the influence of added Drinking water treatment residuals on the extractability and availability of phosphorus to plants; determination of the agronomic rate of alum to different agricultural soils and evaluation of the alum as ameliorating material for soil conditions and plant growth were investigated. In all studied soils, increasing drinking water treatment residuals rate up to 30 g/kg significantly increased dry matter yield. Application of 10, 20 and 30 g/kg alum significantly increased plant P concentrations in the plant materials (shoots and roots) taken from clay, sandy and calcareous soils. Further increase in alum application rate has resulted in negative significant impact on plants P concentration, especially in clay and calcareous soils, but in sandy soils the increase in phosphorusconcentration extended to 40 g/kg alum rate. Application of alum at rates up to 30 g/kg significantly increased available phosphorus concentrations of the three studied soils. However, application of alum at a rate of 40 g/kg to clay and calcareous soils significantly decreased available phosphorus concentrations. Combined analyses of all soils and alum rates studied clearly indicated significant relationship between available phosphorus concentration and phosphorus uptake (r = 0.87, P < 0.001). Based on our experiment results, the rate of 30 g/kg is considered the best application rate of alum because of its positive effects on plant dry matter. Our study clearly demonstrates that alum has potential as a soil amendment to increase plant growth; however, more research is needed to determine beneficial and / or detrimental aspects of this practice under field conditions.     

Nutrient uptake by mulberry and Chinese prickly ash associated with arbuscular mycorrhizal fungi

Understanding how nutrient absorption processes in plants are related to arbuscular mycorrhizal (AM) association is critical for predicting the effects of AM symbiosis on elemental cycling for plants. Both mulberry (Morus alba) and Chinese prickly ash (Zanthoxylum bungeanum) are AM-associated plants, widely distributed in southwest China. It was hypothesized that if the nutrient absorption processes were efficiently associated with AM symbiosis in both mulberry and Chinese prickly ash, foliar nutrient concentrations—especially calcium (Ca)—would be primarily determined by the soil conditions in different regions. To investigate this, AM colonization levels of soils, nutrient levels in soils and leaves, and δ¹³C values of leaves were analyzed for mulberry and Chinese prickly ash. In this study, spore density in soils with low pH was higher than that in soils with high pH. The average concentrations of sugar delivered to roots in both mulberry and Chinese prickly ash in soil with relatively low pH and soil extractable cations were higher than those in other areas. The values of foliar δ¹³C in both mulberry and Chinese prickly ash in low soil-pH and soil extractable cations were lower than those in contrast areas, indicating that water availability was impacted by soil characteristics. The efficiency in AM-mediated processes might play an important role in translocation between soil nutrients and plant tissue. The results suggest uptake and translocation of nutrients, especially Ca, in AM-associated plants may be affected by an efficiency of AM-mediated processes. Since Sr does not appear to be similarly affected, expressing Ca and other nutrient concentrations relative to Sr could be used to evaluate whether the uptake and translocation of Ca and other nutrients are affected by AM-mediated processes.     

路基粒状填土的旋转压实试验

尽管击实试验是目前最流行的室内土体压实试验方法,但实际上与现场任何一种压实方法都无相似之处,且不适用于无粘性土（粒状土）的压实试验。无粘性土的振动击实试验方法也存在很多问题。现代重型压实设备的使用,路基粒状填土的压实密度达到了目前室内规范试验方法不可能达到的水平。介绍了美国采用供高性能沥青路面混合料设计与质量控制之用的旋转压实机对粒状土进行的压实试验。其结果表明,旋转压实试验能有效模拟路基粒状填土的现场压实特征;可采用压实压力200 kPa、旋转角为1.25°、旋转次数为90、旋转速度为20 rpm的试验结果来控制粒状填土路基的现场压实质量。     

广南县幅岩溶区与非岩溶区土壤碳氮磷生态化学计量比空间变异分析

借助1∶25万云南省广南县幅土壤地球化学调查数据,并利用单因素方差分析、多重比较法以及地统计学方法,对岩溶区和非岩溶区土壤碳氮磷生态化学计量特征及其空间分布进行了对比分析。结果显示:广南县幅岩溶区土壤中有机碳（SOC）、全氮（TN）、全磷（TP）含量显著高于非岩溶区,而碳氮比（C∶N）、碳磷比（C∶P）、氮磷比（N∶P）显著低于非岩溶区;无论是岩溶区还是非岩溶区,表层（0～20 cm）SOC、TN、C∶N、C∶P、N∶P均显著高于深层（＞100 cm）。克里格空间插值结果表明,研究区表层土壤中SOC、TN、TP含量具有东高西低的特征,而C∶N、C∶P、N∶P具有低值区集中于东部、高值区散布在西部的空间分布格局。成土母质和土壤类型等自然因素严重制约了研究区土壤碳氮磷的空间变异,同时土地利用变化等人为因素也起到了不可忽视的作用。      

Heavy metal distribution between parent soil and pepper in an unpolluted area,Hainan Island,China

Consuming edible plants contaminated by heavy metals transferred from soil is an important pathway for human exposure to environmental contaminants. In the past several decades, heavy metal accumulation in contaminated soil has been widely studied; however, few researches investigated the background levels of metals in plants and evaluated the difference in plants grown in soils produced from different parent rocks. In this study, a systemic survey of heavy metal distribution and accumulation in the soil–pepper system was investigated in an unpolluted area, Hainan Island, China. Levels of Cu, Pb, Zn and Cd were measured in soils and pepper fruits from five representative pepper-growing areas with different soil parent rocks (i.e. basalt, granite, sedimentary rock, metamorphic rock and alluvial deposits). Average concentrations of Cu, Pb, Zn and Cd in pepper fruits were 11.52, 0.84, 8.77 and 0.05 mg/kg, respectively. The concentrations of heavy metals in soils are controlled by the parent materials and varied greatly from in different areas. Heavy metal contents in all pepper samples were lower than the Chinese maximum contaminant levels. The relationship between heavy metals in soils and biological absorption coefficient (BAC) of pepper fruits suggests that the uptake ability of pepper for soil metals depends mainly on the physiological mechanism, while in some cases, the soil types and supergene environment are also important.     

福建省龙海市表层土壤硒含量及影响因素研究

在龙海市土壤地球化学调查数据基础上,开展土壤硒含量特征、影响因素分析等项研究工作,可为研究区富硒土地资源开发提供依据。本文通过采用原子荧光光谱法(AFS)对福建省龙海市表层土壤4394件样品硒全量进行了分析测试,结果表明:龙海市表层土壤的硒含量为0.031~2.361 mg/kg,平均值为0.354mg/kg,足硒、富硒土壤面积占全地区面积的88.69%。同时发现,成土母质、土地利用方式、土壤pH、有机质含量以及海拔高度是影响龙海市土壤硒含量的重要因素。火山凝灰岩区、花岗岩区成土母质发育的土壤硒含量较高;在不同土地利用方式中,林地土壤的硒含量最高,园地、耕地土壤的硒含量适中;土壤硒含量与有机质含量、海拔高度呈正相关,与pH呈负相关,说明在酸性、富含有机质的土壤环境中硒元素易于富集,尤其是高海拔的山地丘陵区土壤中硒的富集作用更加明显。本研究成果对龙海市土地的合理规划利用、富硒产业的科学发展具有重要价值。     

Heavy metals deposited from the atmosphere on upland Scottish soils: Chemical and lead isotope studies of the association of metals with soil components

Three soil profiles taken from the Hartwood Research Station in Central Scotland have been analyzed using chemical digestion and extraction techniques to investigate the chemical association of heavy metals deposited from the atmosphere. Total digestion, EDTA extraction and the BCR (Bureau Communitaire de Reference) sequential extraction procedure were used. In addition, lead isotope ratios in the whole soils and in the fractions from the sequential extraction procedure were measured using thermal ionisation mass spectrometry. All the digestion and extraction procedures gave clear indication of enhanced concentrations of heavy metals in surface soils, in particular for lead and zinc. Whereas total digestion gave a good indication of the heavy metal status of the soils, the extraction procedures were necessary to provide information on chemical association of the metals with soil components, information needed to understand the soil processes involved in mobilization of metals. Lead isotope analysis of the whole soils revealed a consistent picture of lower ²⁰⁶Pb/²⁰⁷Pb ratios in surface soils (1.140-1.147) than in soils at 20-30 cm depth (1.182-1.190). The steady progression from the lower to higher ratios down the profile was clear indication that anthropogenic lead had penetrated to some degree into the deeper soils. The combination of sequential extraction and lead isotope analysis proved to be a powerful approach to studying this effect in more detail and showed that the fractions extractable from 20 to 30 cm soils contained lead with much lower ²⁰⁶Pb/²⁰⁷Pb ratios (1.174-1.178) than the residual fraction (1.196-1.200). As the extractable fractions contained ≥85% of the lead in the soil, a substantial portion of lead at 20-30 cm depth was of anthropogenic origin. The ²⁰⁶Pb/²⁰⁷Pb ratios of 1.174-1.178 found in the extractable fractions suggested that the mobile component of the anthropogenic lead was that deposited before the introduction of leaded petrol.     

江苏省土壤元素地球化学基准值

土壤元素地球化学基准是指自然环境中土壤元素正常含量,属于土壤固有的化学组成与结构特征。江苏省现有国土面积约102 600 km2,至2007年已经完成全省1∶250 000多目标区域地球化学调查。按照4 km2采集1个样品、采样深度150～200 cm,16 km2分析测试1个组合样,共获得全省6 127个代表自然环境土壤之样品的52个元素与TOC含量的数据,剔除异常含量数据后,以平均含量代表全省土壤元素地球化学基准值、"基准值±1.5或2倍标准离差"表示元素基准值变化范围,获得了江苏省土壤52个元素及TOC的地球化学基准值,为土壤环境评价等提供了基础资料。结果表明:(1)全省土壤大多数元素含量数据不服从正态分布,但剔除异常数据后对平均含量影响不明显;(2)人为活动因素导致江苏土壤的Cd、Hg、Se、N等元素在地表20 cm以上深度发生显著富集,给建立土壤元素地球化学基准值增添了新的难度;(3)成土母质、土壤成因类型与地貌等差异是影响江苏土壤元素含量分布的基本要素。     

Spatial distribution and bioavailability of Hg in vegetable-growing soils collected from the estuary areas of Jiulong River,China

The distribution and bioavailability of Hg in vegetable-growing soils collected from the estuary areas of Jiulong River, China, were studied. Concentrations of Hg in top-soils, soil profiles and plant samples were measured with the method of hydride generation atomic fluorescence spectrometry after microwave digestion. Mercury species in soils were determined with the sequential extraction procedures based on Kingston method. Results showed that Hg concentrations in top-soils ranged from 49.8 to 1,685 ng g^?1, with an average of 510 ng g^?1 which was more than twice higher than the mercury limit (250 ng g^?1 at pH < 6.5) of soil quality set for edible agricultural products in China (HJ 332-2006). High levels of Hg were found to mainly distribute in the top-soils from the northern, western and southern part of the estuary areas. Hg concentrations decreased with the increases of profile depths, except for one sample (S15) in which Hg level in the depth of 0–20 cm was found lower than that in the 20–40 cm. Hg in most of soil samples in non-mobile forms accounted for 46–82 % of total Hg in soils, while Hg in the mobile forms only 0.6–8.7 %. No significant correlation of Hg concentrations between the vegetables and the soils was observed in the studied areas, which indicates that the transfer factors could only reflect the abilities of Hg uptake and accumulation in a specific plant, but they are unsuitable to be used as the general indexes for the mobility and bioavailability of Hg in soils.     

An SMP critical state model for methane hydrate‐bearing sands

Mechanical properties of methane hydrate‐bearing soils are complex. Their behavior undergoes a significant change when hydrates dissociate and become methane gas. On the other hand, methane hydrates are ice‐like compounds and, depending on the hydrate accumulation habits and the degree of hydrate saturation, may cement soil particles into stronger and stiffer soils. A new constitutive model is proposed that is capable of capturing essential characteristics of hydrate‐bearing soils. The core of the model includes the spatial mobilized plane concept; a transformed stress, t_ij; the critical state; and the subloading framework. The proposed model gives soil responses due to stress changes or hydrate saturation changes or both. The performance of the model has been found satisfactory, over a range of hydrate saturation and confining pressures, using triaxial test data from laboratory‐synthesized samples and from field samples extracted from Nankai Trough, Japan. Copyright © 2015 John Wiley & Sons, Ltd.     

Assessment of trace metals contamination in stream sediments and soils in Abuja leather mining,southwestern Nigeria

This study is aimed at determining the level of environmental degradation as well as the concentration of trace elements in soil and stream sediments in order to evaluate the environmental impact of the mining operation. Twenty-five (25) soils and ten (10) stream sediment samples were collected from the study area. The physicochemical parameters were determined using appropriate instrumentation with the aid of a digital pH meter (Milwaukee meter) to measure the pH and electrical conductivity, total dissolved solids, moisture content and loss on ignition of the soil and stream sediment samples. The pH of the soil sample ranged from (6.10 to 7.19); Electrical conductivity ranged from (21.3 to 279.4 µS/cm), moisture content varied from (0.60% to 7.20%), and the LOI ranged from (2.03% to 18.62%). The results of the analysis showed that the concentrations of the trace elements in the soils and stream sediment samples were slightly higher than the background values. Plots of the trace elements in stream sediment samples show moderate, consistent decrease downstream except at points where there was mine water discharge into the main river. The pollution levels of heavy metals were examined in stream sediment and soil samples using different assessable indices, such as the enrichment factor, which showed significant-moderate enrichment for Cr, Th, Nb, Zn, Pb, Y and Zr and the geo-accumulation index, which showed practically moderate contamination with Cr, Ni and Sr based on regional background reference values. Geo-accumulation index and contamination index for soils and stream sediment revealed uncontaminated to moderate contamination. Likewise, elements with moderate contamination were Cr, Ni and Sr. The Pearson correlation showed that there were significant positive associations among selected metals in soil and stream sediment samples.