[Show abstract][Hide abstract]ABSTRACT: A total of 27 surface soil samples were collected to investigate the concentration (aqua regia extractable) and spatial distribution of five major elements (Al, Ba, Fe, Mn and Sr) and seven trace elements (Cd, Cr, Cu, Ni, Pb, V and Zn) in Central Catalonia (NE Spain). The median concentrations (mg kg−1) were: Ba 227, Cd 0.32, Cr 25, Cu 20.3, Ni 23.6, Pb 19.7, Sr 73.7, V 50.2, Zn 72.2, Al 22214, Fe 21754 and Mn 463. The highest median of Ba, Cr, Cu, Ni, Sr, V, Al, Fe and Mn are in soils formed from lutites and those of Cd, Pb and Zn to soils derived from limestones. The soils formed from sandstones have the lowest median values of the studied metals. The spatial distributions of Cr and Ni are similar. The distribution patterns of Cd, Cr, V and Zn have in common higher values in NW, N and NE areas; but Zn, moreover, has high concentration also in the eastern area. In general, the metal higher values occur in the NW, N and NE. Some of them, such Cd, Cr, Ni, Pb and Mn also show significant values in southern-center area. Barium, Cu and Mn show as well higher values in the SE corner of the studied region.Research Highlights► Concentrations of Ba, Cd, Cr, Cu, Ni, Pb, Sr, V, Zn, Al, Fe and Mn in top soils of Central Catalonia (NE Spain). ► Clay and OM contents, EC and pH were related to metal concentrations using correlation and factorial analysis. ► Relationship between these twelve metals of tops soils and their parent rocks. ► The pattern distribution of these twelve metals in top soils of Central Catalonia (NE Spain).
[Show abstract][Hide abstract]ABSTRACT: In Peru, the leaf miner Phyllocnistis citrella attacks citrus crops, including the economically important species Citrus aurantifolia, adversely affecting production. The objective of this work was to determine the in vitro pathogenic ability of enterobacteria isolated from within P. citrella. In addition, the pathogenic effects of these enterobacterias were tested on the predator insects Hippodamia convergens and Chrisoperna externa, on the host plant C. aurantifolia and on rats. The insects were captured in plantations of C. aurantifolia in the Piura Region. Phyllocnistys citrella was the most frequently occurring pest (98%), among other identified pests. From diseased larvae of P. citrella, the bacteria Serratia sp., Pseudomonas sp., and Enterobacter aerogenes were isolated. The three bacterial species had a similar pathogenic effect on P. citrella after 48 h (74.1% average mortality). Serratia sp. caused the highest mortality after 24 h in H. convergens (40%) and C. externa (30%), whereas the Lowest mortality rates were induced at 72 h by E. aerogenes on C. externa (3%) and by Pseudomonas sp. on H. convergens (10%). The bacteria did not affect neither C. aurantifolia or the rats, which gained the same weight as control animals.
No preview · Article · Mar 2009 · SPANISH JOURNAL OF AGRICULTURAL RESEARCH
[Show abstract][Hide abstract]ABSTRACT: Concentrations of Cd, Cr, Ni, Pb, and Zn in the top-(0-10 cm) and sub-surface (10-20 cm) soils of the Talcahuano urban area were measured. The main soil properties (organic matter, CaCO3, pH, particle sizes) were determined for a network of representative sampling sites. The mean Cr, Ni, Pb, and Zn contents in the urban topsoil samples from Talcahuano (37.8, 22.6, 35.2, 333 mg kg(-1), respectively) were compared with mean concentrations for other cities around the world. The results revealed higher concentrations of heavy metals in topsoil samples than in sub-surface samples. The samples from IS1, IS2, and IS3, located in the Talcahuano industrial park, had higher Cr, Ni, Pb, and Zn contents than did samples from the other sites. This was probably due to local pollution by industrial (metallurgical) dust, although other diffuse pollution throughout the entire port region (shipyards, metallurgy, the dismantling of old ships), and contributions from the wind from adjacent industrial, storage, and vessel areas clearly played a role. Heavy metals were lowest in the sample taken on school grounds (SG).
Full-text · Article · Jun 2008 · Environmental Monitoring and Assessment
[Show abstract][Hide abstract]ABSTRACT: In Piura (Peru), the pest Phyllocnistis citrella Stainton damages the photosynthetic rate and new bud production of Citrus aurantiifolia Swingle (sweet lemon), decreasing the yield, productivity and commercial price of its fruit. Biological control was evaluated through the crossed effect of bacteria obtained from pests (Anastrepha fraterculus Wied., Ceratitis capitata Wied. and Rhynchophorus palmarum L.) that are pathogenic against their original host species. Enterobacter cloacae (Jordan) Hormaeche & Edwards and Serratia marcescens Bizio (from A. fraterculus and C. capitata) and Pseudomonas mendocina Palleroni (from R. palmarum) were used against P. citrella. The bacterial strains were inoculated into its food and the accumulated mortality was evaluated. Larvae of P. citrella treated with P. mendocina had the highest mortality (66.7%). These bacterial species were entomopathogenic against the original source pest in laboratory and greenhouse bioassays, and this result widens the pathological activity range of these bacterial species.
No preview · Article · Apr 2007 · Pest Management Science
[Show abstract][Hide abstract]ABSTRACT: The objective of this article is to establish baseline concentrations of Ba, Cr, Cu, Ni, Pb, Sr, V, and Zn (aqua regia-extractable) in natural surface soils of the Torrelles Municipal District and to investigate the relationships between these elements and soil properties and between the element concentrations themselves. Upper baseline concentrations of these elements were (mg kg –1): Ba 272.6, Cr 40.8, Cu 31.0, Ni 29.9, Pb 68.1, Sr 83.0, V 49.7, and Zn 132.7; most corresponded with the values reported in the literature. Correlation analysis showed that total Fe and Al have the strongest relationships with trace elements.
Full-text · Article · Dec 2006 · Environmental Forensics
[Show abstract][Hide abstract]ABSTRACT: Restoration returns an ecosystem to a state that is as similar as possible to its natural condition. Soil is a critical component of all ecosystems. To evaluate natural variations in concentrations of trace elements and to assess trace metal contamination in soils, it is necessary to survey trace metal background values.This study determines the concentrations of barium (Ba), copper (Cu), chromium (Cr), nickel (Ni), lead (Pb), strontium (Sr), vanadium (V), and zinc (Zn) (aqua regia-extractable) based on 22 representative natural (i.e. uncultivated) surface soils of the Sant Climent Municipal District (Catalonia, Spain); it establishes the geochemical baseline concentrations and investigates possible relationships between soil properties and trace element concentrations.The obtained geochemical baseline concentrations (mg kg−1) were Ba 146.0–561.0, Cr 13.8–115.0; Cu 11.0–92.2; Ni 12.4–130.6, Pb 11.7–152.7, Sr 17.5–146.2, V 11.5–121.2, and Zn 10.7–356.0.Soil properties, including pHw, organic carbon (OC), clay fraction, cation-exchange capacity (CEC), total Fe, and total Al concentrations were related to metal concentration using correlation analysis. Total Fe and Al showed the strongest relationships with concentrations of most trace elements.