Monitoring and assessment of soil and forage molybdenum near an atmospheric source

Forage and soil molybdenum (Mo) were measured in the vicinity of a Mo processing plant in southwestern Pennsylvania, USA. Molybdenum concentrations in red clover plants (Trifolium pratense L.), measured at 23 sites, ranged from 1.1 to 56.6 mg kg^–1. Fourteen of the 23 sites sampled had red clover plants with Mo concentrations over the threshold value of 6 mg kg^–1. Red clover Cu:Mo concentration ratios were below the recommended ratio of 4 in 19 of the sites. The low Cu:Mo values, along with high plant Mo concentrations, indicates that there is a potential risk of molybdenosis in ruminant animals in this area. Acid digested (sorbed) soil Mo concentrations, measured at 30 sites, ranged from 7.0 (background level) to 131 mg kg^–1. Using the Baker Soil Test (BST) extract, molybdenum soil concentrations ranged from 0.01 to 3.99 mg kg^–1. Regression equations were developed to predict plant uptake of soil Mo based on the red clover plant, soil extracts and soil pH data. The R-squared values for predicting plant uptake were 81.9% for the BST extract and 81.6% for the acid digestion extract plus soil pH. Based on the above results, a protocol has been implemented for assessing the risk of high soil Mo near this Mo processing plant.     

Monitoring air,soil, stream and fish for aerial drift of permethrin

Permethrin drift from two aerial applications at each of two sites in a potato growing area in Ontario were measured to a maximum distance of 61 m outside the treatment area. Droplet drift did not enter the adjacent surface water streams at either study site, since there was little or no wind on the four occasions. The concentration of the insecticide in soil as a result of drifting off site was significantly lower than the amount deposited on the treatment area. The spray drifting off-target was generally made up of droplets <100 m. Permethrin residues were detected in the water and sediment samples collected after treatment along the Bailey Creek and Beeton Creek; however, these levels did not cause lethal or sublethal effects to aquatic invertebrates and fish species. Based on the conditions and results of this study, it is concluded that a buffer zone of 65 m around sensitive and productive bodies of water would be effective and practical.     

Monitoring of heavy metals uptake and allocation in Pinus sylvestris organs in alkalised soil

The concentration of heavy metals in soil and in Scots pine (Pinus sylvestris) organs growing on a pH gradient from 4.0 to 7.9 of soil at different distances from a cement plant was monitored. Emission for over 40 years of alkaline dust (pH 12.3-12.6) into the atmosphere in North Estonia had resulted in alkalisation and elevated concentration of total heavy metals in upper layers of the soil (0-30 cm), which was considerable even 10 years after the dust pollution stopped. Monitoring showed that the accumulation and allocation of heavy metals varied between the stem, shoots and needles and differed from the trees in the unpolluted area, depending more on the mobility of elements and the pH than element concentrations in the alkaline soil. A strong negative correlation was found between the soil pH and Mn, Zn and Cd concentrations in different tree organs. Compared to the unpolluted area, Pb was present in relatively higher concentrations in all organs but Cr, Fe and Cu in needles and shoots. The concentrations of Mn and Cd were much lower than control in all organs of trees in alkalised soil. The height increment and density of needles on shoots were predominantly in negative correlation with the pH of soil.     

Assessing the removal potential of soil-aquifer treatment system (soil column) for endotoxin

Soil-aquifer treatment (SAT) of wastewater is an increasingly valued practice for replenishing aquifers due to ease of operation and low maintenance needs and therefore low cost. In this study, we investigated the fate of endotoxins through laboratory-scale SAT soil columns over a four month period. The effluent of rapid sand filtration was run through the columns under gravity flow conditions. Four SAT columns were packed with four different filter materials (fine sand, medium sand, coarse sand and very coarse sand). The effluent of rapid sand filtration (average dissolved organic carbon (DOC) = 4 mg l(-1) and average endotoxin concentration = 4 EU ml(-1)) was collected from a domestic wastewater treatment plant in Sapporo, Japan. DOC removal ranged from 12.5% to greater than 22.5% during the study, with DOC levels averaging 3.1 and 3.5 mg l(-1) for the SAT columns packed with different soils. Endotoxin transformation exhibited different profiles, depending on the time and soil type. Reduction in endotoxin concentration averaged 64.3% and was as high as 86.7% across the soil columns 1, 2, 3 and 4, respectively. While DOC removal was gradual, the reductions in endotoxin levels were rather rapid and most of the removal was achieved in the top layers. Soil with a larger grain size had lower efficiency in removing endotoxin. Tests were performed to evaluate the transformation of organic matter showing endotoxicity and to determine the mechanisms responsible for changes in the structural and size properties of dissolved organic matter (OM) during SAT. Dissolved OM was fractionated using Sep-Pack C18 Cartridges into hydrophobic and hydrophilic fractions. Dialysis tubes with different molecular weight cut-offs were used to perform size fractions of OM showing endotoxicity. Evaluation of the transformation of organic matter showing endotoxicity during SAT indicated that both hydrophobic and large molecules were reduced. Moreover, experimental findings showed that adsorption test data fit to the Freundlich isotherm and were affected by the particle grain size with higher adsorption capacity for fine and medium sand.     

Distribution,bioavailability, and potential ecological risk of Cu,Pb, and Zn in soil in a potential groundwater source area

In this study, we examined three horizontal and vertical soil profiles along a sewage drainage ditch in order to determine the spatial distribution of Cu, Pb, and Zn in soils and to assess the bioavailability and potential ecological risks associated with these metals in a potential groundwater source area. Results showed that the concentrations of Cu, Pb, and Zn were approximately at background level, suggesting that human activities (industrial and agricultural pollution) had a negligible influence on these metals in soil, and that the concentrations reflected the natural background levels in the study area. Cu, Pb, and Zn concentrations were slightly higher in topsoil (0–20 cm) than deeper in the soil profile. Using a modified BCR sequential extraction method to evaluate the mobility and bioavailability of metals showed that the potential bioavailability sequence of Cu, Pb, and Zn at three depths in the soil profile was in the order Cu?≈?Pb?<?Zn. The potential ecological risk from the metals was evaluated using risk assessment code, and the results suggest that Cu and Zn pose no or low risk, while there is a low or medium risk from Pb. Results from groundwater monitoring showed that the groundwater was not polluted by leaching from soil.     

Effect of land use land cover change on soil erosion potential in an agricultural watershed

Universal soil loss equation (USLE) was used in conjunction with a geographic information system to determine the influence of land use and land cover change (LUCC) on soil erosion potential of a reservoir catchment during the period 1989 to 2004. Results showed that the mean soil erosion potential of the watershed was increased slightly from 12.11 t ha^???1 year^???1 in the year 1989 to 13.21 t ha^???1 year^???1 in the year 2004. Spatial analysis revealed that the disappearance of forest patches from relatively flat areas, increased in wasteland in steep slope, and intensification of cultivation practice in relatively more erosion-prone soil were the main factors contributing toward the increased soil erosion potential of the watershed during the study period. Results indicated that transition of other land use land cover (LUC) categories to cropland was the most detrimental to watershed in terms of soil loss while forest acted as the most effective barrier to soil loss. A p value of 0.5503 obtained for two-tailed paired t test between the mean erosion potential of microwatersheds in 1989 and 2004 also indicated towards a moderate change in soil erosion potential of the watershed over the studied period. This study revealed that the spatial location of LUC parcels with respect to terrain and associated soil properties should be an important consideration in soil erosion assessment process.     

Study of the potential of barnyard grass for the remediation of Cd- and Pb-contaminated soil

In this study, the microwave digestion method was used to determine total cadmium (Cd) and lead (Pb) concentrations, the BCR method was used to determine different states of Cd and Pb, and atomic absorption spectroscopy (AAS) and inductively coupled plasma optical emission spectrometry (ICP-OES) were used to determine Cd and Pb concentrations in simulated soil and barnyard grass before and after planting barnyard grass to provide a theoretical basis for the remediation of Cd- and Pb-contaminated soil. The results showed that the bioconcentration factor changes with different Cd concentrations are relatively complex and that the removal rate increases regularly. The 100 mg kg^?1 Cd treatment had the highest removal rate, which reached 36.66%. For Pb, the bioconcentration factor decreased and tended to reach equilibrium as the Pb concentration increased. The highest removal rate was 41.72% and occurred in the 500 mg kg^?1 Pb treatment; however, this removal rate was generally lower than that of Cd. In addition, the reduction state had the highest change rate, followed by the residual, acid soluble and oxidation states. For Pb, the residual state has the highest change rate, followed by the acid soluble state, reduction state and oxidation state. In addition, a significant correlation was observed between the soil Pb and Cd concentrations and the concentrations of Pb and Cd that accumulated in the belowground biomass of the barnyard grass, but no significant correlation was observed between the soil Pb and Cd concentrations and the amounts of Pb and Cd that accumulated in the aboveground biomass of the barnyard grass. The highest transfer factor of Cd was 0.49, which occurred in the 5 mg kg^?1 Cd treatment. The higher transfer factor of Pb was 0.48 in the 100 mg kg^?1 Pb treatment. All of these factors indicate that the belowground biomass of barnyard grass plays a more important role in the remediation of Cd- and Pb-contaminated soils than the aboveground biomass of barnyard grass. Remediation should occur through phytostabilization. Thus, with its strong adaptability and lush growth, barnyard grass can be applied as a pioneer species for the phytoremediation of Cd- and Pb-contaminated soils.     

Monitoring results for organochlorine pesticides in soil and water from selected obsolete pesticide stores in Pakistan

Seasonal changes in micromineral and macromineral concentrations in tissues of shrimp (Parapenaus longirostris) from Marmara Sea were measured for a 1-year period by using inductively coupled plasma mass spectrometer. The contents of investigated minerals in shrimp were found to be in the range of 0.374–0.716 mg/kg for Hg, 0.526–1.286 mg/kg for Se, 0.007–0.098 mg/kg for Cd, 0.197–0.230 mg/kg for Pb, 5.194–7.600 mg/kg for Cu, 11.090–17.707 mg/kg for Zn, 22.128–38.850 mg/kg for Al, 61.769–88.437 mg/kg for Fe, 0.262–0.368 mg/kg for As, 0.081–0.249 mg/kg for Co, 0.850–1.459 mg/kg for Mn, 0.316–0.507 mg/kg for Ni, 0.032–0.107 mg/kg for Sn, 1.262–1.502 mg/kg for Cr, 2,813.770–3,317.819 mg/kg for Na, 3,702.230–4,479.648 mg/kg for K, 495.782–650.280 mg/kg for Mg, 790.407–1,016.112 mg/kg for Ca, 2,685.873–3,657.658 mg/kg for P, and 0.454–0.942 mg/kg for I. The levels of Hg found in autumn were higher than maximum levels proposed by the European legislation.     

Characterization of soil heavy metal contamination and potential health risk in metropolitan region of northern China

Soil in metropolitan region suffers great contamination risk due to the rapid urbanization especially in developing countries. Beijing and Tianjin, together with their surrounding regions, form a mega-metropolitan region in northern China. To assess the soil environmental quality, a total of 458 surface soil samples were collected from this area. Concentrations of Cr, Cu, Pb, Zn, As, Cd, and Hg were analyzed and compared to the Chinese environmental quality standards for soil. Multivariate analysis was carried out to identify the possible sources and Geographic Information Systems techniques were applied to visualize the spatial data. It was found that the primary inputs of As were due to pedogenic sources, whereas Hg was mainly of anthropogenic source. Other elements including Cr, Cu, Pb, Zn, and Cd were from both lithogenic and anthropogenic origins. Health risk assessment based on the maximum heavy metal concentration indicated that As derived from sewage irrigation area can result in carcinogenic lifetime risk due to ingestion and/or dermal contact of soil. The potential non-carcinogenic risk for children is significant for Pb and the cumulative effect of multiple metals is of concern for children in the vicinity of mining site. The results increased our knowledge for understanding natural and anthropogenic sources as well as health risk for metals in metropolitan soil.     

Monitoring and assessment of toxic metals in Gulf War oil spill contaminated soil using laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) was applied for the detection of toxic metals in oil spill contaminated soil (OSCS). The OSCS samples were collected from Khursania Saudi Arabia along the coast of Persian Gulf exposed to oil spills in 1991 Gulf war. Environmentally important elements like Aluminum Magnesium, Calcium, Chromium, Titanium, Strontium, Iron, Barium, Sodium, potassium, Zirconium and Vanadium from the contaminated soil have been detected. Optimal experimental conditions for analysis were investigated. The LIBS system was calibrated using standard samples containing these trace elements. The results obtained using Laser-Induced Breakdown Spectroscopy (LIBS) were compared with the results obtained using Inductively Coupled Plasma Emission Spectroscopy (ICP). The concentrations of some elements (Ba and Cr) were found higher than permissible safe limits. Health risks associated with exposure to such toxic elements are also discussed.     

北京市通州污灌区土壤环境质量监测和蔬菜重金属污染状况研究

通过对北京市通州污灌区土壤现状调查与蔬菜重金属污染监测,结合土壤环境质量标准、食品卫生标准及污灌区污染历史,分析对比该区土壤和蔬菜重金属污染状况及其变化。结果表明,本次监测通州污灌区土壤中重金属平均含量均达到土壤环境质量标准(GB15618-1995)中二级标准限量。对照土壤中的重金属Cu、Pb、Cr、Cd和As均达到土壤一级标准。凉水河两岸和通惠北干渠中重金属含量均高于对照土壤,说明污灌区污水灌溉已使土壤受到一定程度的污染。与二十世纪70年代末监测结果相比,土壤中多数重金属含量处于上升趋势。污灌区蔬菜重金属含量监测结果表明,其含量水平均达到食品卫生标准,说明污灌区蔬菜尚未受到严重污染。     

Monitoring the effects of chelating agents and electrical fields on active forms of Pb and Zn in contaminated soil

The application of electrical fields and chelating agents is an innovative hybrid technology used for the decontamination of soil polluted by heavy metals. The effects of four center-oriented electrical fields and chelating agents on active fractions of lead and zinc were investigated in this pot experiment. Ethylenediaminetetraacetic acid (EDTA) as a synthetic chelator and cow manure extract (CME) and poultry manure extract (PME) as natural chelators were applied to the pots (2 g kg^?1) 30 days after the first irrigation. Two weeks later, four center-oriented electrical fields were applied in each pot (in three levels of 0, 10, and 30 V) for 1 h each day for 14 days. The soil near the cathode and anodes was collected and analyzed as cathodic and anodic soil, respectively. Results indicated that the soluble–exchangeable fraction of lead and zinc were decreased in the cathodic soil, while the carbonate-bound fractions were increased. In the anodic soil, however, the opposite result was observed. EDTA enhanced the soluble–exchangeable form of the metals in both anodic and cathodic soils. Furthermore, the amounts of carbonate-bound heavy metals were increased by the application of CME in both soils. The organic-bound fraction of the metals was increased by the application of natural chelators, while electrical fields had no significant impacts on this fraction.     

Monitoring of soil and groundwater contamination following a pipeline explosion and petroleum product spillage in Ijegun, Lagos Nigeria

In May 2008, an accidental damage of a Nigerian National Petroleum Corporation (NNPC) pipeline occurred in Ijegun area of Lagos, Nigeria, resulting in oil spillage and consequent contamination of the environment. The residual concentration of the total hydrocarbon (THC) and benzene, toluene, ethylbenzene, and xylene (BTEX) in the groundwater and soil was therefore investigated between March 2009 and July 2010. Results showed elevated THC mean levels in groundwater which were above the World Health Organization maximum admissible value of 0.1 mg/l. THC values as high as 757.97 mg/l in groundwater and 402.52 mg/l in soil were observed in March 2009. Pronounced seasonal variation in the concentration of THC in groundwater and soil samples show that there was significant (P?<?0.05) difference in the measured concentration of THC between each season (dry and wet), with the highest being in the dry season and between the years 2009 and 2010. Significant hydrocarbon contamination, 500 m beyond the explosion site and 25 months after the incident, was observed revealing the extent of the spillage of petroleum products. The highest concentrations of 16.65 μg/l (benzene), 2.08 μg/l (toluene), and 4864.79 μg/l (xylene) were found in stations within the 100 m buffer zone. Most of the samples of groundwater taken were above the target value of 0.2 μg/l set for BTEX compounds by the Environmental Guidelines and Standards for Petroleum Industry in Nigeria. The level of hydrocarbon in the impacted area calls for concern and remediation of the area is urgently needed to reduce further negative impact on the ecosystem.     

Heavy metal contamination from mining sites in South Morocco: Monitoring metal content and toxicity of soil runoff and groundwater

The aim of the present work is the assessment of metal toxicity in runoff, in their contaminated soils and in the groundwater sampled from two mining areas in the region of Marrakech using a microbial bioassay MetPLATE™. This bioassay is based on the specific inhibition of the β-galactosidase enzyme of a mutant strain of Escherichia coli, by the metallic pollutants. The stream waters from all sampling stations in the two mines were all very toxic and displayed percent enzyme inhibition exceeding 87% except SWA₄ and SWB₁ stations in mine C. Their high concentrations of copper (Cu) and zinc (Zn) confirm the acute toxicity shown by MetPLATE. The pH of stream waters from mine B and C varied between 2.1 and 6.2 and was probably responsible for metal mobilization, suggesting a problem of acid mine drainage in these mining areas. The bioassay MetPLATE™ was also applied to mine tailings and to soils contaminated by the acidic waters. The results show that the high toxicity of these soils and tailings was mainly due to the relatively concentration of soluble Zn and Cu. The use of MetPLATE™ in groundwater toxicity testing shows that, most of the samples exhibited low metal toxicity (2.7–45.5% inhibition) except GW3 of the mine B (95.3% inhibition during the wet season and 82.9% inhibition during the dry season). This high toxicity is attributed to the higher than usual concentrations of Cu (189 μg Cu l⁻¹) and Zn (1505 μg Zn l⁻¹). These results show the potential risk of the contamination of different ecosystems situated to the vicinity of these two metalliferous sites. The general trend observed was an increase in metal toxicity measured by the MetPLATE with increasing total and mobile metal concentrations in the studied matrices. Therefore, the MetPLATE bioassay is a reliable and fast bioassay to estimate the metals toxicity in the aquatic and solids samples.     

Petroleum contaminated soil in Oman: Evaluation of bioremediation treatment and potential for reuse in hot asphalt mix concrete

This paper presents a study that aims at evaluating the leaching characteristics of petroleum contaminated soils as well as their application in hot mix asphalt concrete. Soil samples are environmentally characterized in terms of their total heavy metals and hydrocarbon compounds and leachability. The total petroleum hydrocarbon (TPH) present in the PCS before and after treatment was determined to be 6.8% and 5.3% by dry weight, indicating a reduction of 1% in the TPH of PCS due to the current treatment employed. Results of the total heavy metal analysis on soils indicate that the concentrations of heavy metals are lower when extraction of the soil samples is carried out using hexane in comparison to TCE. The results show that the clean soils present in the vicinity of contaminated sites contain heavy metals in the following decreasing order: nickel (Ni), followed by chromium (Cr), zinc (Zn), copper (Cu), lead (Pb), and vanadium (V). The current treatment practice employed for remediation of the contaminated soil reduces the concentrations of nickel and chromium, but increases the concentrations of all remaining heavy metals.     

环境中苯并(a)芘监测技术及建议

环境中BaP是引起人们各类癌症的主要诱发物.叙述了环境中BaP的来源及其浓度状况,列举了国家制定的各项标准中的BaP含量的浓度限值,论述了环境水中和空气中BaP的样品采集、保存、前处理、分析测定及定量监测中应注意的几个问题,提出了监测BaP的4点建议.     

以监测网深化环境监测工作

本文根据多年从事监测工作的体会和对各类监测站的调查研究,评述了当前地方监测工作和行业、企业监测工作中存在的一些问题,提出了用切实运转的监测网来深化和开拓监测工作的建议,并对监测网的组建和运转作了较为可行的建议和设想。