Heavy metal contamination in soils and food crops around Dabaoshan mine in Guangdong,China: implication for human health

This study was designed to investigate heavy metal (Cu, Zn, Pb, and Cd) contamination levels of soils, vegetables, and rice grown in the vicinity of the Dabaoshan mine, south China. The concentration of Cu, Zn, Pb, and Cd in paddy soil exceeded the maximum allowable concentrations for Chinese agricultural soil. The heavy metal concentrations (mg kg⁻¹, dry weight basis) in vegetables ranged from 5.0 to 14.3 for Cu, 34.7 to 170 for Zn, 0.90 to 2.23 for Pb, and 0.45 to 4.1 for Cd. The concentrations of Pb and Cd in rice grain exceeded the maximum permissible limits in China. Dietary intake of Pb and Cd through the consumption of rice and certain vegetable exceeded the recommended dietary allowance levels. The status of heavy metal concentrations of food crops grown in the vicinity of Dabaoshan mine and their implications for human health should be further investigated.     

Clearance and Fragmentation of Tropical Deciduous Forest in the Tierras Bajas, Santa Cruz, Bolivia

Abstract: The Tierras Bajas is an area of 20,000 km ² of lowland deciduous forest in eastern Santa Cruz, Bolivia, that has undergone rapid change during the past two decades. As part of the largest remaining area of intact deciduous tropical forest in the world, it has been nominated a priority area for conservation by several environmental organizations. We quantified the spatial and temporal patterns of deforestation in the area by digital processing of high-resolution satellite imagery from 1975 through 1998. The estimated rate of deforestation was among the highest in the world for such a limited area, ranging from 160 km ²/year in the early1980s to almost 1200 km ²/year in the late 1990s. Although most deforestation up to 1984 was in Bolivian peasant and Mennonite colonies, most deforestation after 1984 was in non-Mennonite industrial soybean farms. The level of fragmentation of uncut forest, caused by the spatial patterns of deforestation, also differed among these broad land-use types. Deforestation in planned and spontaneous peasant colonies was complex in shape, forming relatively large areas of edge-affected forest, whereas that in Mennonite and other industrial farms was in large, rectangular increments, creating relatively less edge. But the distribution of these farms and the practice of initially clearing around the peripheries of properties resulted in the isolation of large areas of forest. In 1998 four-fifths of the remaining forest were either within 1 km of a clearance edge or in isolated fragments of <50 km². Compared with deforested areas, the areas of isolated and edge-affected forest were disproportionately large during the early stages of frontier colonization. These results imply that if the fragmentation effects of deforestation are to be minimized, conservation planning must occur at the earliest stages of frontier development.     

Sociogenetic structure in a free-living nocturnal primate population: sex-specific differences in the grey mouse lemur (Microcebus murinus)

The grey mouse lemur (Microcebus murinus) has a dispersed social structure, within which female sleeping associations are common. These sleeping associations have been hypothesised to confer anti-predatory and thermoregulatory benefits, especially when rearing offspring. The genetic composition of these associations was determined using microsatellite markers to test predictions derived from kin selection theory. 161 (99 males, 62 females) individual M. murinus belonging to a free-living population in Ampijoroa, north-western Madagascar, were genotyped and observed over a total of 13 months distributed over the dry seasons of 3 successive years (1995-1997). Kin selection theory predicts that these female associations should consist of closely related members, and that female philopatry and male natal dispersal should characterise the dispersal pattern within this species. These predictions were confirmed by the data. Five out of six female sleeping groups consisted of one or more closely related dyads. Females that slept alone did not have close female kin in the vicinity or within the population at all. Closely related female dyads lived in significantly closer proximity than closely related male dyads and closely related male-female dyads showed intermediate proximity. In combination with the result that females possessed significantly more relatives within the population than males, these findings support the behavioural hypotheses of female philopatry and male natal dispersal. Matrilinear grouping patterns and sex-biased dispersal are therefore genetically established in a dispersed primate social organisation for the first time. The results further indicate that several generations of mouse lemurs live together within a given area, implying both an effective mechanism of kin recognition to avoid father-daughter incest and the potential for social learning to ensure individual recognition.     

Chemical indicators of anthropogenic impacts in sediments of the pristine karst lakes

The anthropogenic impact on the pristine karst lakes was investigated using combination of specific parameters, including multielemental analysis of major inorganic constituents (Al, K, Fe) and trace metals (Li, Ag, Cd, Sn, Pb, Bi, Cr, Co, Ni, Cu, Zn and Sb), polycyclic aromatic hydrocarbons (PAHs) and anionic surfactants of linear alkylbenzene sulfonate (LAS) type. The study was performed in the Plitvice Lakes National Park, situated in a sparsely populated area of the northwestern Dinarides, central Croatia. Dated cores of recent sediments from the two biggest lakes, Lake Prosce and Lake Kozjak, were analysed for the selected contaminants using highly specific methods, involving inductively coupled plasma mass spectrometry (ICP/MS), gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS). The concentration of inorganic constituents reflected primarily the geological background of the area as well as geomorphological and geochemical characteristics of the Plitvice Lakes. Due to the higher terrigenous input, the concentration of all elements was significantly higher in the Lake Prosce. The concentration of toxic metals was relatively low in both lakes, except for Cd (>1 mg kg⁻¹) and Pb (up to 40 mg kg⁻¹). The vertical profiles of these metals suggested that elevated concentrations of Cd were of natural origin, derived from the erosion of the Jurassic dolomite bedrock, while Pb was predominately of recent anthropogenic origin. A similar distribution pattern, suggesting the same prevailing mechanism of input, was observed for pyrolytic PAHs. The characteristic diagnostic PAH ratios revealed that higher PAHs prevailingly originated from the combustion of biomass and fossil fuels. LAS, which represent highly specific indicators of untreated wastewaters, were found in rather high concentrations in the recent sediment layers (up to 4.7 mg kg⁻¹), suggesting that contaminated household and hotel wastewaters reach the Lakes, very probably by leaking through the porous karst rocks.     

Concentration-dependent RDX uptake and remediation by crop plants

The potential RDX contamination of food chain from polluted soil is a significant concern in regards to both human health and environment. Using a hydroponic system and selected soils spiked with RDX, this study disclosed that four crop plant species maize (Zea mays), sorghum (Sorghum sudanese), wheat (Triticum aestivum), and soybean (Glycine max) were capable of RDX uptake with more in aerial parts than roots. The accumulation of RDX in the plant tissue is concentration-dependent up to 21 mg RDX/L solution or 100 mg RDX/kg soil but not proportionally at higher RDX levels from 220 to 903 mg/kg soil. While wheat plant tissue harbored the highest RDX concentration of 2,800 μg per gram dry biomass, maize was able to remove a maximum of 3,267 μg RDX from soil per pot by five 4-week plants at 100 mg/kg of soil. Although RDX is toxic to plants, maize, sorghum, and wheat showed reasonable growth in the presence of the chemical, whereas soybeans were more sensitive to RDX. Results of this study facilitate assessment of the potential invasion of food chain by RDX-contaminated soils.     

Combustion in porous media and its applications – A comprehensive survey

The rapid advances in technology and improved living standard of the society necessitate abundant use of fossil fuels which poses two major challenges to any nation. One is fast depletion of fossil fuel resources; the other is environmental pollution. The porous medium combustion (PMC) has proved to be one of the technically and economically feasible options to tackle the aforesaid problems to a remarkable extent. PMC has interesting advantages compared with free flame combustion due to the higher burning rates, the increased power dynamic range, the extension of the lean flammability limits, and the low emissions of pollutants. This article provides a comprehensive picture of the global scenario of research and developments in PMC and its applications that enable a researcher to decide the direction of further investigation. The works published so far in this area are reviewed, classified according to their objectives and presented in an organized manner with general conclusions. A separate section is devoted for the numerical modeling of PMC.     

Proposal for new best estimates of the soil-to-plant transfer factor of U,Th, Ra,Pb and Po

There is increasing interest in radiological assessment of discharges of naturally occurring radionuclides into the terrestrial environment. Such assessments require parameter values for the pathways considered in predictive models. An important pathway for human exposure is via ingestion of food crops and animal products. One of the key parameters in environmental assessment is therefore the soil-to-plant transfer factor to food and fodder crops. The objective of this study was to compile data, based on an extensive literature survey, concerning soil-to-plant transfer factors for uranium, thorium, radium, lead, and polonium. Transfer factor estimates were presented for major crop groups (Cereals, Leafy vegetables, Non-leafy vegetables, Root crops, Tubers, Fruits, Herbs, Pastures/grasses, Fodder), and also for some compartments within crop groups. Transfer factors were also calculated per soil group, as defined by their texture and organic matter content (Sand, Loam, Clay and Organic), and evaluation of transfer factors' dependency on specific soil characteristics was performed following regression analysis. The derived estimates were compared with estimates currently in use.     

Vulnerability and risk evaluation of agricultural nitrogen pollution for Hungary's main aquifer using DRASTIC and GLEAMS models

In recent years, the significant improvement in point source depuration technologies has highlighted problems regarding, in particular, phosphorus and nitrogen pollution of surface and groundwater caused by agricultural non-point (diffuse) sources (NPS). Therefore, there is an urgent need to determine the relationship between agriculture and chemical and ecological water quality.This is a worldwide problem, but it is particularly relevant in countries, such as Hungary, that have recently become members of the European Community. The Italian Foreign Ministry has financed the PECO (Eastern Europe Countries Project) projects, amongst which is the project that led to the present paper, aimed at agricultural sustainability in Hungary, from the point of view of NPS. Specifically, the aim of the present work has been to study nitrates in Hungary's main aquifer. This study compares a model showing aquifer intrinsic vulnerability to pollution (using the DRASTIC parameter method; Aller et al. [Aller, L., Truman, B., Leher, J.H., Petty, R.J., 1986. DRASTIC: A Standardized System for Evaluating Ground Water Pollution Potential Using Hydrogeologic Settings. US NTIS, Springfield, VA.]) with a field-scale model (GLEAMS; Knisel [Knisel, W.G. (Ed.), 1993. GLEAMS—Groudwater Leaching Effects of Agricultural Management Systems, Version 3.10. University of Georgia, Coastal Plain Experimental Station, Tifton, GA.]) developed to evaluate the effects of agricultural management systems within and through the plant root zone. Specifically, GLEAMS calculates nitrate nitrogen lost by runoff, sediment and leachate.Groundwater monitoring probes were constructed for the project to measure: (i) nitrate content in monitored wells; (ii) tritium (³H) hydrogen radioisotope, as a tool to estimate the recharge conditions of the shallow groundwater; (iii) nitrogen isotope ratio δ¹⁵N, since nitrogen of organic and inorganic origin can easily be distinguished.The results obtained are satisfactory, above all regarding the DRASTIC evaluation method, which is shown to satisfactorily explain both low and high aquifer vulnerability, and furthermore proves to be a good tool for zoning hydrogeological regions in terms of natural system susceptibility to pollution. The GLEAMS model, however, proves not to be immediately usable for predictions, above all due to the difficulty in finding sufficient data for the input parameters. It remains a good tool, but only after an accurate validation, for decision support systems, in the specific case to integrate intrinsic vulnerability, from DRASTIC (or similar methods), with land use nitrate loads from GLEAMS, or similar methods.The PECO project has proved a positive experience to highlight the fundamental points of a decision support system, aimed to mitigate the nitrate risk for groundwater coming from Hungarian agricultural areas.     

Seasonal variations of monosaccharide anhydrides in PM1 and PM2.5 aerosol in urban areas

The concentrations of monosaccharide anhydrides (levoglucosan, mannosan, galactosan) in PM1 and PM2.5 aerosol samples were measured in Brno and ?lapanice in the Czech Republic in winter and summer 2009. 56 aerosol samples were collected together at both sites to investigate the different sources that contribute to aerosol composition in studied localities. Daily PM1 and PM2.5 aerosol samples were collected on pre-fired quartz fibre filters.The sum of average atmospheric concentration of levoglucosan, mannosan and galactosan in PM1 aerosol in ?lapanice and Brno during winter was 513 and 273 ng m^?3, while in summer the sum of average atmospheric concentration of monosaccharide anhydrides (MAs) was 42 and 38 ng m^?3, respectively. The sum of average atmospheric concentration of MAs in PM1 aerosol formed 71 and 63% of the sum of MA concentration in PM2.5 aerosol collected in winter in ?lapanice and Brno, whereas in summer the sum of average atmospheric concentration of MAs in PM1 aerosol formed 45 and 43% of the sum of MA concentration in PM2.5 aerosol in ?lapanice and Brno, respectively.In winter, the sum of MAs contributed significantly to PM1 mass ranging between 1.37% and 2.67% of PM1 mass (Brno – ?lapanice), while in summer the contribution of the sum of MAs was smaller (0.28–0.32%). Contribution of the sum of MAs to PM2.5 mass is similar both in winter (1.37–2.71%) and summer (0.44–0.55%).The higher concentrations of monosaccharide anhydrides in aerosols in ?lapanice indicate higher biomass combustion in this location than in Brno during winter season. The comparison of levoglucosan concentration in PM1 and PM2.5 aerosol shows prevailing presence of levoglucosan in PM1 aerosol both in winter (72% on average) and summer (60% on average).The aerosol samples collected in ?lapanice and Brno in winter and summer show comparable contributions of levoglucosan, mannosan and galactosan to the total amount of monosaccharide anhydrides in both aerosol size fractions. Levoglucosan was the most abundant monosaccharide anhydride with a relative average contribution to the total amount of MAs in the range of 71–82% for PM1 aerosols and 52–79% for PM2.5 aerosols.     

Biofilm controlled sorption of selected acidic drugs on river sediments characterized by different organic carbon content

The sorption process of selected non-steroidal anti-inflammatory drugs (ibuprofen, naproxen, ketoprofen, diclofenac) on biofilm covered river sediments were investigated in laboratory. In the course of the experiments, the effect of pH of aqueous phase, the effect of TOC (total organic carbon) content of biofilm on the sorption processes were studied. The determination of concentration of drugs was performed by gas chromatography mass spectrometry (GC-MS) both in liquid and solid phases. The pseudo-first-order rate constant of the sorption was found to be 83 min(-1). The effect of pH on the sorption of diclofenac was significantly lower than the obtained values in case of the other three drugs. The calculated K(d) (sorption coefficient) values increased in the sequence of ibuprofen, naproxen, ketoprofen and diclofenac and varied between 0.1-0.4; 0.2-0.7; 0.2-1.2; 0.2-1.4 kg L(-1) respectively, depending on the characteristics of the sediments. The value of K(d)×f(oc) showed a straight line as function of f(oc) (fraction of organic carbon) therefore, instead of the widely distributed normalization process (K(d)/f(oc)), an empirical equation (K(d)=A/f(oc)+B) was suggested for estimation of the K(d) values in case of different TOC content sediments.