Characterization of microbial communities from coastal waters using microarrays

Molecular methods, including DNA probes, were used to identify and enumerate pathogenic Vibrio species in the Chesapeake Bay; our data indicated that Vibrio vulnificus exhibits seasonal fluctuations in number. Our work included a characterization of total microbial communities from the Bay; development of microarrays that identify and quantify the diversity of those communities; and observation of temporal changes in those communities. To identify members of the microbial community, we amplified the 16S rDNA gene from community DNA isolated from a biofilm sample collected from the Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or more similar to 7 species including two recently described Shewanella species, baltica and frigidimarina, that have not been previously isolated from the Chesapeake. When the genera of bacteria from biofilm after culturing are compared to those detected by subcloning amplified 16S fragments from community DNA, the cultured sample exhibited a strong bias. In oysters collected in February, the most common bacteria were previously unknown. Based on our 16S findings, we are developing microarrays to detect these and other microbial species in these estuarine communities. The microarrays will detect each species using four distinct loci, with the multiple loci serving as an internal control. The accuracy of the microarray will be measured using sentinel species such as Aeromonas species, Escherichia coli, and Vibrio vulnificus. Using microarrays, it should be possible to determine the annual fluctuations of bacterial species (culturable and non-culturable, pathogenic and non-pathogenic). The data may be applied to understanding patterns of environmental change; assessing the health of the Bay; and evaluating the risk of human illness associated with exposure to and ingestion of water and shellfish.     

Competitive Retention of Lead and Cadmium on an Agricultural Soil

Lead and cadmium contamination of an agricultural soil has been studied using batch and column experiments. Thermodynamics of theretention phenomena may be represented by a Langmuir isotherm foran aqueous metal concentration up to 100 mg L^-1. First order kinetics with respect to the solid phase yield good predictabilityfor both batch and column experiments. Kinetics and thermodynamics of lead retention predominate over those ofcadmium. As a consequence, lead is preferentially retainedand can even displace sorbed cadmium. In the event of anspill involving both metals, cadmium would move further inthe soil and its aqueous concentration downstream could beeven higher than that of the influent solution, increasingpotential risks. A two-region model has been used to fit all the experimental results. Satisfactory predictions for column experiments are obtained with parameters which are consistent with those obtained for the batch experiments, for which sorption is described by a Langmuir isotherm including competitive retention.     

Water quality test based on dielectrophoretic measurements of fresh water algae Selenastrum capricornutum

A method is described whereby dielectrophoresis of algal cells is used to perform rapid water quality analysis, specifically detecting the presence of CuSO4. The dielectric collection spectrum of the fresh water alga Selenastrum capricornutum was determined for a range of concentrations of CuSO4 from 25 mg L(-1) to 0.25 mg L(-1) for exposure times of 15 min and 18 h. In all cases increasing the concentration of CuSO4 reduced cell collection, but a step reduction was observed in collection between 2 mg L(-1) and 5 mg L(-1). This method has potential for forming a rapid, low-cost test for water quality with broad specificity and significantly reduced analysis time compared to current methods.     

Monitoring of the three organophosphate esters TBP,TCEP and TBEP in river water and ground water (Oder,Germany)

The behaviour of the three organophosphate esters tributyl phosphate (TBP), tris(2-chloroethyl)phosphate (TCEP) and tris(2-butoxyethyl)phosphate (TBEP) during infiltration of river water to ground water has been investigated. The monitoring site is the Oder River and the adjacent Oderbruch aquifer. From March 2000 to July 2001, 76 ground water samples from monitoring wells located close to the Oder River and nine river water samples were collected. Additionally, influent and effluent samples from local waste water treatment plants, one sample of rain water and samples of roof runoff were collected. All samples were analysed by solid-phase-extraction followed by gas chromatography/mass spectrometry. TBP, TCEP and TBEP were detected at mean values of 622 ng l(-1), 352 ng l(-1), and 2955 ng l(-1), respectively in municipal waste water effluents. This points to a major input of these compounds into the Oder River by municipal waste water discharge. The concentrations of TBP and TBEP decreased downstream the Oder River possibly due to aerobic degradation. TBP, TCEP and TBEP were detected in ground water influenced predominantly by bank-filtered water. This demonstrates a transport of organic compounds by river water infiltration to ground water. TBP, TCEP and TBEP were also detected in rain water precipitation, roof runoff and ground water predominantly influenced by rain water infiltration. This hints to an input of these compounds to ground water by dry and wet deposition after atmospheric transport. Organophosphate esters were also detected in parts of the aquifer at 21 m depth. This demonstrates low anaerobic degradation rates of TBP, TCEP and TBEP.     

Distribution of polychlorinated biphenyls (PCBs) and organochlorine pesticides in soils from the East Antarctic coast

Concentrations of hexachlorobenzene (HCB), alpha-, beta- and gamma-hexachlorocyclohexane (HCH) isomers, 6 o,p'-and p,p'-isomers of DDT and 28 PCB congeners have been measured in eleven soil samples and one lichen collected on the Eastern coast of Antarctica from 5 Russian stations. For samples with low concentrations of PCBs (range 0.20-0.41 ng g(-1) dry weight) and pesticides (0.86-4.69 ng g(-1) and 0.11-1.22 ng g(-1) dry weight for HCHs and DDTs, respectively), atmospheric long-range transport from Africa, South America or Australia was suggested as the sole source of contamination. The profile of PCB congeners was dominated by the more volatile tri-, tetra- and penta-PCBs congeners, thus supporting long-range transport hypothesis. Four samples contained moderate levels of PCBs (range 1.98-6.94 ng g(-1) dry weight) and variable concentrations of pesticides (gamma-HCH, p,p'-DDT and o,p'-DDT being the main contaminants). For samples with high concentrations of PCBs (range 90.26-157.45 ng g(-1)) and high concentrations of pesticides, the presence of high molecular weight PCB congeners such as: 153, 180, 187, 170 etc, strongly suggest a local source (biotic) of PCBs rather than atmospheric transport. It is likely that on a local scale, biotic focussing of pollutants, due to bird activities (nesting and excrement) can cause high contamination levels and become more significant than contaminant input via abiotic pathways.     

Prediction of the solubility of zinc, copper, nickel, cadmium, and lead in metal-contaminated soils

Risk assessment of metal-contaminated soil depends on how precisely one can predict the solubility of metals in soils. Responses of plants and soil organisms to metal toxicity are explained by the variation in free metal ion activity in soil pore water. This study was undertaken to predict the free ion activity of Zn, Cu, Ni, Cd, and Pb in metal-contaminated soil as a function of pH, soil organic carbon, and extractable metal content. For this purpose, 21 surface soil samples (0–15 cm) were collected from agricultural lands of various locations receiving sewage sludge and industrial effluents for a long period. One soil sample was also collected from agricultural land which has been under intensive cropping and receiving irrigation through tube well water. Soil samples were varied widely in respect of physicochemical properties including metal content. Total Zn, Cu, Ni, Cd, and Pb in experimental soils were 2,015?±?3,373, 236?±?286, 103?±?192, 29.8?±?6.04, and 141?±?270 mg kg^?1, respectively. Free metal ion activity, viz., pZn²⁺, pCu²⁺, pNi²⁺, pCd²⁺, and pPb²⁺, as estimated by the Baker soil test was 9.37?±?1.89, 13.1?±?1.96, 12.8?±?1.89, 11.9?±?2.00, and 11.6?±?1.52, respectively. Free metal ion activity was predicted by pH-dependent Freundlich equation (solubility model) as a function of pH, organic carbon, and extractable metal. Results indicate that solubility model as a function of pH, Walkley–Black carbon (WBC), and ethylenediaminetetraacetic acid (EDTA)-extractable metals could explain the variation in pZn²⁺, pCu²⁺, pNi²⁺, pCd²⁺, and pPb²⁺ to the extent of 59, 56, 46, 52, and 51 %, respectively. Predictability of the solubility model based on pH, KMnO₄-oxidizable carbon, and diethylenetriaminepentaacetic acid-extractable or CaCl₂-extractable metal was inferior compared to that based on EDTA-extractable metals and WBC.     

Biodegradation or simple adsorption to the support material? Development of a simple, fast and low-cost technique

Biofilms are present in several areas and are studied in microbiology, medical sciences, biology and, of course, sanitary engineering. Biofilms are used for the treatment of municipal wastewater, and their application was even before the invention of the activated sludge process. The main objective of this work was to develop a simple, fast and low-cost technique to evaluate the nature of the first decay in the concentration of an organic compound in the presence of a solid material. Though simple, the technique developed has allowed the clarification of whether the initial concentration decay is due to adsorption to the support material or a result of biodegradation. The results show that, with two different support materials, adsorption does not take place, and the biodegradation processes are responsible for the first decay in the organic concentration. The technique used offers a fast and low-cost way of studying the existence of adsorption. Two feed concentration solutions and two different support materials were used.     

Delineating shallow saline groundwater zones from Southern India using geophysical indicators

A geophysical survey was conducted over an industrial belt encompassing 80 functional leather factories in Southern India. These factories discharge untreated effluents which pollute shallow groundwater where electrical conductivity (EC) value had a wide range between 545 and 26,600 μS/cm (mean, 3, 901 μS/cm). The ranges of Na⁺ and Cl^? ions were from 46 to 4,850 mg/L (mean, 348 mg/L) and 25 to 10,390 mg/L (mean, 1,079 mg/L), respectively. Geoelectrical layer parameters of 37 vertical electrical soundings were analyzed to demarcate fresh and saline water zones. However, the analysis not did lead to a unique resolution of saline and fresh waters. It was difficult to assign a definitive value to the aquifer resistivity of any area. Thus, geophysical indicators, namely longitudinal unit conductance (S), transverse unit resistance (T), and average longitudinal resistivity (R _s), were calculated for identifying fresh and saline waters. Spatial distributions of S, T, and R _s reflected widely varying ranges for the saline and fresh water zones. Further, the empirical relation of formation factor (F) was established from pore-water resistivity and aquifer resistivity for fresh and saline aquifers, which may be used to estimate local EC values from the aquifer resistivity, where well water is not available.     

Main results of strategic noise maps and action plans in Navarre (Spain)

According to Directive 2002/49, strategic noise maps and their correspondent action plans were carried out in the Autonomous Community of Navarre, Spain. Six strategic noise maps were produced for 120 km of major roads as well as a strategic noise map for the Agglomeration of the Region of Pamplona (ARP) with a population of 280,199 inhabitants. In the ARP, a total of 36,400 people (13.0 %) are exposed to Ln levels over 55 dBA and 42,300 people (15.1 %) are exposed to Lden levels over 65 dBA. With regard to major roads, a total of 3,900 people are exposed to Ln levels over 55 dBA and 2,400 people are exposed to Lden levels over 65 dBA. When designing action plans, different prioritisation criteria concerning rank-based effectiveness measures (mainly the amount of people benefitting from them) were taken into account.     

Alteration of antioxidant enzymes and impairment of DNA in the SiO2 nanoparticles exposed zebra fish (Danio rerio)

The incorporation of nanoparticles in industrial and biomedical applications has increased significantly in recent years, yet their hazardous and toxic effects have not been studied extensively. While standard toxicological test methods are generally capable of detecting the toxic effects, the choice of relevant methods for nanomaterials is still discussed. Among the various oxide nanomaterials, silica nanoparticles are widely used in biological applications that include nano-medicine. But studies on adverse effects of silica nanoparticle exposure to fish remain unclear. Therefore, the present study was designed to investigate the oxidative toxic effects of silicon dioxide nanoparticles using fish model. The size of the SiO₂ nanoparticles was between 68 and 100 nm which was confirmed by X-ray diffractometer, dynamic light scattering, scanning electron microscope and transmission electron microscope. The zebra fish were exposed to sub-lethal concentrations (5 and 2.5 mg/L) of characterized SiO₂ nanoparticles for a period of 7 days. After 7 days, SiO₂ nanoparticle-treated fishes were sacrificed, and tissues such as liver, muscle and gill were dissected out for the analysis of antioxidant enzymes and DNA fragmentation. The DNA profiles were analysed in the tissues of zebra fish that treated with SiO₂ nanoparticles. Tissues of fish from clean water were used as control, and DNA profiles were analysed. It is found that DNA from control tissues was intact, whereas the tissues treated with SiO₂ were all fragmented. SiO₂ nanoparticle-mediated antioxidant enzymes activities, such as catalase, superoxide dismutase, glutathione (GSH)-S-transferase, glutathione reductase and GSH, in the tissues of zebra fish were measured. The results revealed that alteration of antioxidant enzymes due to SiO₂ nanoparticle can be considered as a biomarker to SiO₂-mediated oxidative stress in biological samples.