Evaluation of ground water denitrification at a biosolids disposal site

A study was conducted at a sanitary sewage sludge(biosolids) disposal site in Springfield, Illinois, U.S.A. todetermine if biological denitrification played a significantfactor in attenuation of ground water nitrate values. The siteselected for this study is a 23 ha (57 acre) dedicatedbiosolids disposal facility located adjacent to a 75.7 millionliter per day (20 million gallons per day) municipal treatmentplant that uses anaerobic solids stabilization for treatment ofgenerated biosolids material. Biosolids have been disposed of byfixed-point spray applicators at the site since 1976, which hascaused ground water nitrate levels to increase significantlyabove background levels. A method was developed using aconservative chemical tracer to simulate the biosolidsapplication process and monitor the ground water directly beneaththe simulated disposal site. Results demonstrated a net declineof nitrates that could not be attributed to dilution alone.While the monitoring methodology developed for this study didnot directly estimate the denitrification rate, a rate foroverall nitrate reduction was calculated that could be consideredto take into account all transport and reduction mechanisms suchas denitrification, advection, dispersion and dilution.     

Characterization of surface runoff from a subtropics urban catchment

Characteristics of surface runoff from a 0.14-km^2 urban catchment with separated sewer in Macau was investigated. Water quality measurements of surface runoff were carried out on five rainfall events during the period of August to November, 2005. Water quality parameters such as pH, turbidity, TSS, COD, TN, Zn, Pb, and Cu were analyzed. The results show that TN and COD are the major pollutants from surface runoff with mean concentration of 8.5 and 201.4 mg/L, both over 4-fold higher compared to the Class V surface water quality standard developed by China SEPA. Event mean concentration （EMC） for major pollutants showed considerable variations between rainfall events. The largest rainfall event with the longest length of antecedent dry weather period （ADWP） produced the highest EMC of TN, TSS and COD. From the pollutographs analysis, the peak concentration of TN precedes the peak runoff flow rate for all three rainfall events. The tendency of the concentration of TSS, turbidity and COD changing with runoff flow varies between rainfall events. The relationship between TSS and other parameters were analyzed to evaluate the efficiency of the physical treatment process to control the surface runoff in the urban catchment. Based on the correlation of parameters with TSS, high treatment efficiency of TSS, TN and COD was expected. The most significant event in term of first flush is the one with the strongest rainfall intensity and longest length of ADWP. TN always showed first flush phenomenon in all three rainfall events, which suggested that the surface runoff in the early stage of surface runoff should be dealt with for controlling TN losses during rainfall events.     

A previously unrecognized group of Middle Jurassic triconodontan mammals from Central Asia

Ferganodon narynensis gen. et sp. nov. is represented by a lower molariform tooth from the Middle Jurassic (Callovian) Balabansai Svita in Kyrgyzstan. The new genus is allied with Klamelia zhaopengi Chow and Rich 1984 from the Middle Jurassic Shishugou Formation in Xinjiang, northwest China to the new family Klameliidae based on parallelogram-shaped lower molariforms, imbricating rather than interlocking of cusps e-d-f, by a peculiar distolabial cingulid cusp, and by vertical folding of the enamel on the labial crown side. The new family Klameliidae fam. nov. is most similar to Gobiconodontidae by the structure of the molariform teeth and represents a previously unrecognized radiation of eutriconodontan mammals possibly endemic to Central Asia.     

Export of toxic chemicals - a review of the case of uncontrolled electronic-waste recycling

This paper reviews the concentrations of persistent organic pollutants such as flame retardants (PBDEs), dioxins/furans (PCDD/Fs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals/metalloid concentrations of different environmental media at Guiyu, a traditional rice-growing village located in southeastern Guangdong Province (PR China), which has turned into an intensive electronic-waste (e-waste) recycling site. Incomplete combustion of e-waste in open air and dumping of processed materials are the major sources of various toxic chemicals. By comparing with existing data available in other areas and also guidelines adopted in different countries, it is obvious that the environment is highly contaminated by these toxic chemicals derived from the recycling processes. For example, the monthly concentration of the sum of 22 PBDE congeners contained in PM(2.5) (16.8ngm(-3)) of air samples at Guiyu was 100 times higher than published data. In order to safeguard the environment and human health, detailed investigations are urgently needed, especially on tracking the exposure pathways of different toxic chemicals which may affect the workers and local residents especially mothers, infants and children.     

Aquatic ecotoxicity assessment of a new natural formicide

Background, aim and scope

Agrochemicals could reach aquatic ecosystems and damage ecosystem functionality. Natural formicide could be an alternative to use in comparison with the more toxic formicides available on the market. Thus, the objective of this study was to assess the ecotoxicity of the new natural formicide Macex? with a battery of classical aquatic ecotoxicity tests.

Material and methods

Bacteria (Aliivibrio fischeri), algae (Pseudokirchneriella subcapitata), hydra (Hydra attenuata), daphnids (Daphnia magna), and fish (Danio rerio) tests were performed in accordance with international standardized methodologies.

Results

In the range of formicide concentrations tested (0.03 to 2.0?g?L^?1) EC₅₀ values varied from 0.49 to >2.0?g?L^?1, with P. subcapitata being the most sensitive species and H. attenuata and D. rerio the most tolerant species to this product in aqueous solutions.

Conclusions

This new formicide preparation can be classed as a product of low toxicity compared to the aquatic ecotoxicity of the most common commercialized formicides.     

Solanum nigrum grown in contaminated soil: effect of arbuscular mycorrhizal fungi on zinc accumulation and histolocalisation

Zn tissue accumulation in Solanum nigrum grown in a non-contaminated and a naturally contaminated Zn matrix and the effect of inoculation with different arbuscular mycorrhizal fungi (AMF) on metal uptake were assessed. S. nigrum grown in the contaminated soil always presented higher Zn accumulation in the tissues, accumulating up to 1622 mg Zn kg(-1). The presence of both Glomus claroideum and Glomus intraradices enhanced the uptake and accumulation of Zn by S. nigrum (up to 83 and 49% higher Zn accumulation, respectively). The main deposits of the metal were found in the intercellular spaces and in the cell walls of the root tissues, as revealed by autometallography, with the inoculation with different AMF species causing no differences in the location of Zn accumulation. These findings indicate that S. nigrum inoculated with selected heavy metal tolerant AMF presents extracting and accumulating capacities, constituting a potentially suitable remediation method for Zn polluted soils.     

Natural tree collectives of pure oriental spruce [Picea orientalis (L.) Link] on mountain forests in Turkey

Distribution area of oriental spruce [Picea orientalis (L.) Link.] in the world is only in the north-east of Turkey and Caucasian. Because of being the semi monopoly tree with respect to its distribution and representing the upper forest line, it is necessary to analyse, evaluate and model the stand structures of oriental spruce forests in Turkey. In this research, some sampling plots were selected in timberline and treeline in the subalpine forest zone in Turkey. In these sampling plots some information about occurrence and development of the tree collectives was obtained. A total of 12 sampling plots (6 in timberline and 6 of them in treeline) were studied and horizontal and vertical stand profiles were obtained, while number of trees ranges between 2-86 in the tree collectives in treeline and in timberline 3-12. According to this, area per tree in treeline and in timberline is determined as 1.02 m2 and 3.75 m2 on an average respectively. Mean age of trees to reach breast height is 43 years in treeline sampling plots and 22 years in timberline sampling plots. According to the ratio of h (mean height) / d1.30 (diameter at breast height), stand stability values were calculated and it was determined if the stands were stable on the basis of the sampling plots. Stability values of the sampling plots changed between 33 and 75.     

Study of summer heat exposure at the ground services operations of a main international airport in Saudi Arabia

Summer heat in coastal subtropical Jeddah, augmented by heat from operating ground servicing equipment in King Abdul-Aziz International Airport (KAAIA), presents a major occupational problem to ground service operators, particularly the air traffic control coordinator (ATCC), that hinders their work efficiency and induces health disorders to them. The present study was conducted to assess the magnitude of this problem and propose heat control strategy and remedial actions for the Saudi Arabian Airlines (SAUDIA). Heat parameters including air temperature (T (a)), wet bulb temperature (T (w)), globe temperature (T (g)) and air velocity were measured around serviced planes and in other locations used by ATCC, and the WBGT and the ATCC-WBGT-TWAs were computed. Mostly all the T (a) measurements, and many T (w) measurements, were higher than T (a) and T (w) forecasted by the Presidency of Meteorology and Environment (PME) due to heat dissipated from operating vehicles and equipment in service. The measured and PME forecasted parameters have good and medium linear correlations (T (a): r (2) = 0.74 and T (w): r (2) = 0.64). The computed WBGT in the service stations around planes are considerably higher than the 25 and 27.5 degrees C recommended TLV(R) for non-acclimatized and acclimatized operators. However, the computed ATCC- WBGT-TWA levels indicate that the shift-work-schedule which was recommended to be implemented by SAUDIA has successfully reduced their heat exposure to acceptable levels, except for a very few operators (6.7% exceeding WBGT-TLV(R) of 25 degrees C and 2.2% exceeding TLV(R) of 27.5 degrees C) for whom the shift-work schedules might be corrected to achieve safe heat exposure.     

Effects of various fatty acid amendments on a microbial digester community in batch culture

Since biogas production is becoming increasingly important the understanding of anaerobic digestion processes is fundamental. However, large-scale digesters often lack online sensor equipment to monitor key parameters. Furthermore the possibility to selectively change fermenting parameter settings in order to investigate methane output or microbial changes is limited. In the present study we examined the possibility to investigate the microbial community of a large scale (750,000 L) digester within a laboratory small-scale approach. We studied the short-term response of the downscaled communities on various fatty acids and its effects on gas production and compared it with data from the original digester sludge. Even high loads of formic acid led to distinct methane formation, whereas high concentrations of other acids (acetic, butyric, propionic acid) caused a marked inhibition of methanogenesis coupled with an increase in hydrogen concentration. Molecular microbial techniques (DGGE/quantitative real-time-PCR) were used to monitor the microbial community changes which were related to data from GC and HPLC analysis. DGGE band patterns showed that the same microorganisms which were already dominant in the original digester re-established again in the lab-scale experiment. Very few microorganisms dominated the whole fermenting process and species diversity was not easily influenced by moderate varying fatty acid amendments - Methanoculleus thermophilus being the most abundant species throughout the variants. MCR-copy number determined via quantitative real-time-PCR - turned out to be a reliable parameter for quantification of methanogens, even in a very complex matrix like fermenter sludge. Generally the downscaled batch approach was shown to be appropriate to investigate microbial communities from large-scale digesters.     

Environmental impact reduction through ecological planning at Bahia Magdalena, Mexico

For analyzing basic marine and coastal characteristics we selected the potential sites where shrimp culture could be developed in a large coastal zone, Bahia Magdalena, Baja California Sur, Mexico. Based on our analysis, 6 sites were preselected and field stages of work were then developed to assess the precise suitability of each site in order to develop the proposed aquaculture activities. In ranking the suitability we were able to recommend the most appropriate places to develop shrimp culture in this region. Also, knowing the exact biological, physico-chemical and social environment, we determined the best species to cultivate, the recommended total area and the methodology to be used to lessen the environmental impact and to obtain the maximum profitability Our methodology could be used not only to select appropriate sites for shrimp culture in other coastal lagoons, but it also could be applied to assess the suitability in a quick and accurate way, of any other production activity in coastal zones.