Groundwater flow models are applied to a large variety of hydrogeological conditions in different aquifer types, in order to simulate the groundwater flow of the investigated system. This paper aims to present the application of a groundwater flow model for the simulation of a sedimentary aquifer, located in Northern Greece. The simulation involves the period between April 2003 and April 2004, and the model is divided into two distinct stress periods, each containing two different time steps. The simulation of the aquifer is found to be satisfactory, conclusion which is based on both graphical as well as arithmetical verifications. The groundwater flow simulation was achieved by the application of the MODFLOW code.

Near-infrared diffuse reflectance sensing (NIRS) of soils has been the object of considerable interest and research in the last few years. This has been motivated by the prospect that this method seems to provide a cheap, convenient alternative to conventional, time-consuming methods for the measurement of a wide range of soil parameters. In particular, various authors have advocated that NIRS could be used to measure rapidly and non-destructively the concentration of trace metals in surface soils. Correlation analyses between NIRS spectra and trace metal concentration have yielded inconclusive results to date, suggesting that trace metal concentration may belong to a class of “tertiary” soil parameters, linked to NIRS spectra through “surrogate”, or indirect, correlations, involving some other primary or secondary parameter like clay or organic matter content, to which NIRS spectra are very sensitive. To assess the validity of this surrogate correlation hypothesis in the case of trace metals, experiments were carried out with soil samples varying only in the amount of trace metals they contain. Field-aged Hudson and Arkport soil pots spiked with Cu and Zn, freshly spiked samples of the same soils, and samples of a metalliferous peat soil from Western New York naturally rich in Cd and Zn were subjected to NIRS under laboratory conditions. Detailed analysis indicates that the NIR spectrum is sensitive to sample handling, including the orientation of the samples in the NIRS instrument, but that, at the same time, there is no discernable effect of the presence of trace metals on any part of the NIR spectrum. These results provide strong experimental support to the hypothesis of “surrogate” correlation for trace metals, and indicate that trace metals, even in severely contaminated soils, should not interfere with the NIR sensing of primary or secondary parameters, like organic matter content. Further work is needed to determine if this feature of NIR spectra extends to other soil chemical parameters.

Diverting the infiltrating water away from the zone of N application can reduce nitrate-nitrogen (NO₃-N) leaching losses to groundwater from agricultural fields. This study was conducted from 2001 through 2005 to determine the effects of N-application methods using a localized compaction and doming (LCD) applicator and spoke injector on NO₃-N leaching losses to subsurface drainage water and corn (Zea mays L.)-soybean (Glycine max L.) yields. The field experiments were conducted at the Iowa State University's northeastern research center near Nashua, Iowa, on corn-soybean rotation plots under chisel plow system having subsurface drainage ‘tile' system installed in 1979. The soils at the site are glacial till derived soils. The N-application rates of 168 kg-N ha⁻¹ were applied to corn only for both the treatments each replicated three times in a randomized complete block design. For combined 5 years, the LCD N-applicator in comparison with spoke injector showed lower flow weighted NO₃-N concentrations in tile water (16.8 vs. 20.1 mg L⁻¹) from corn plots, greater tile flow (66 vs. 49 mm), almost equivalent NO₃-N leaching loss with tile water (11.5 vs. 11.3 kg-N ha⁻¹) and similar corn grain yields (11.17 vs. 11.37 Mg ha⁻¹), respectively, although treatments effects were found to be non-significant (p = 0.05) statistically. The analysis, however, revealed that amount and temporal distribution of the growing season precipitation also affected the tile flow, NO₃-N leaching loss to subsurface drain water, and corn-soybean yields. Moreover, the spatial variability effects from plot to plot in some cases, resulted in differences of tile flow and NO₃-N leaching losses in the range of three to four times despite being treated with the same management practices. These results indicate that the LCD N-applicator in comparison with spoke injector resulted in lower flow weighted NO₃-N concentrations in subsurface drain water of corn plots; however, strategies need to be developed to reduce the offsite transport of nitrate leaching losses during early spring period from March through June.

Microwave (MW) is applied to enhance pentachlorophenol (PCP) removal using zerovalent iron (ZVI, Fe⁰) or granular activated carbon (GAC) as the dielectric media. Applying MW energy at 700 W for 20 s, the results show that Fe⁰ is capable of enhancing the CB removing 2.7 times (91% vs. 34 %) than GAC. Because Fe⁰ has higher dielectric loss (39.5 F/m vs. 8.3 F/m), it absorbs more MW energy to speed up the oxidation rate resulting in a faster temperature rise than GAC. Thus, in the presence of MW, Fe⁰ is superior to GAC for PCP removal. Additionally, excessive MW exposure will damage the surface structure of either Fe⁰ or GAC causing excessive electric charges to accumulate in the media that brings about the phenomenon of sparks.

The main objective of this study was to find out a cost-effective treatment methodology for the treatment of palm oil effluent (POE) obtained from a food processing industry. An electro-Fenton pretreatment and biological oxidation has been suggested for the removal of recalcitrant contaminants present in POE. An initial COD of about 6,700 mg/L of POE was subjected to electrolytic degradation for 2 h and subsequently by biological oxidation. The biological oxidation was carried out using Aspergillus niger and Pseudomonas putida in anaerobic condition. Electro-Fenton process removed 48.35% of the COD. Biological oxidation subsequently decreased the COD to 86.12% and BOD to 85.23%. In the combined process, a high reduction in TOC and TN were achieved. Experimental conditions have been optimized and performances of these techniques have been discussed. The treated water can be reused for general and agricultural purposes.

This study evaluated the effect of lead (Pb(II)), zinc (Zn(II)) and copper (Cu(II)) on growth and sporulation of four Halophytophthora species (Halophytophthora vesicula, Halophytophthora elongata, Halophytophthora spinosa var. lobata, and an oogonia-producing Halophytophthora sp.) isolated from different mangrove sites in Taiwan. Results show that all isolates grew well or even better at 1 ppm concentration of the heavy metals tested. Growth of all test isolates was totally inhibited at 500 ppm, except for H. spinosa var. lobata exposed to Zn(II). For sporulation, all isolates produced moderate to abundant zoosporangia or oogonia at 1 ppm Pb(II) and Zn(II). Production of zoosporangia by H. vesicula, H. elongata and H. spinosa var. lobata was significantly affected or totally inhibited at 1 ppm Pb(II) and Zn(II) and all concentrations of Cu(II). Abnormal oogonia were produced by Halophytophthora sp. at 10 ppm Cu(II) and 100 ppm of the three heavy metals. In general, Cu(II) and Zn(II) were found to be the most toxic, and the least toxic was Pb(II). H. spinosa var. lobata was the most tolerant to all the heavy metals, while H. vesicula and H. elongata were the most sensitive. Results of this study shows that increased concentrations of Pb(II), Cu(II), and Zn(II) in the mangrove environment can significantly affect growth and impair normal reproduction of Halophytophthora species.

Many natural vegetation species have been shown to be negatively affected by ozone. This study has investigated how the presence of competing species in a community affects two common responses to ozone: visible injury and senescence. Monocultures and mixtures of Trifolium repens and Lolium perenne were grown in large containers and were exposed in solardomes to either a rural episodic ozone profile (AOT40 of 12.86 ppm h) or control conditions (AOT40 of 0.02 ppm h) for 12 weeks. The proportion of ozone-injured or senesced leaves was different in the different regions of the canopy. The highest proportions of injured/senesced leaves were in the plant material growing at the edge of the canopy and the upper canopy, with a significantly lower proportion of injured leaves in the inner canopy. The presence of L. perenne increased the proportion of ozone-injured leaves in T. repens at the final harvest, whilst the presence of T. repens decreased the proportion of senesced leaves in L. perenne. In L. perenne, the proportion of injured leaves at the edge and inner canopy decreased significantly when grown in competition, whilst for T. repens the reverse effect occurred in the inner canopy only. Different mechanisms appeared to influence the interaction between response to ozone and competitors in these two species. In L. perenne the response to ozone may have been related to nitrogen supply, whereas in T. repens canopy structure was more important.

Phosphorus (P) loss from agricultural soils to water is a major contributor to eutrophication. In an incubation experiment with five contrasting soils, lime and gypsum showed potential as source measures to decrease P loss risk, as assessed by water extractions. Soils were incubated with lime to achieve a target pH of 6.5 and with gypsum at equivalent Ca rates for 108 days. P was added (17 kg P ha⁻¹) as KH₂PO₄ in solution. Gypsum appears to have greater potential as a source measure, decreasing molybdate-reactive P (RP) solubility by 14-56% and organic P (OP) by 10-53% across all soils. RP and Ca may have precipitated or co-sorbed, and OP may have been stabilised in organic matter complexes due to the bridging effect of Ca and the flocculating effect of increased ionic strength. Greater effectiveness of gypsum may be due to its higher solubility and the fact that it increases Ca concentrations without increasing pH. Lime decreased RP solubility in two soils (by 4% and 20%) but increased solubility in two and had no effect in a third. The overall effect of lime may depend on several competing effects of raised pH and Ca concentration that may vary in importance depending on soil characteristics such as base cation and P status. For the highest P status soil, both lime and gypsum were effective, decreasing RP solubility by 4% and 15%, respectively. Targeted treatment of high P soils may be an effective and economical strategy to minimise P losses.

Changes in dissolved organic matter (DOM) characteristics were investigated during a storm event in the Kyungan River using UV-visible, fluorescence spectroscopy, resin fractionation, and size exclusion chromatography (SEC). Water samples were collected at nine sampling times to reflect a variation of the river water level. A dramatic increase was observed for chemical oxygen demand (COD) versus biochemical oxygen demand, suggesting that non-biodegradable organic components may be more contained in the organic matters driven by the storm. Specific UV absorbance values increased from 2.15 to 3.16 L/mgC-m, reaching the maximum level at the highest water level. The storm runoff resulted in the reduction of protein-like fluorescence (PLF), the increase of fulvic-like and humic-like fluorescence for the synchronous fluorescence spectra of DOM. Weight-average molecular weight (MWw) values increased from 1,100 to 1,510 Da due to the increment of high MW fractions in the SEC chromatograms. Overall changes in DOM composition may be explained by the inflow of soil-derived DOM from the upstream basins brought by the storm. The humification index (HIX) exhibited a positive correlation with MWw values, suggesting that HIX may be suggested to a prediction descriptor for DOM MW during the storm event. PLF presented a negative correlation with DOM MW, suggesting that protein-like fluorescent compounds are associated with low MW components in the river. More input of humic substances by the storm runoff appears to shift DOM into a higher MW value as revealed by a positive correlation between MWw and hydrophobic fraction.

The chemical dynamics at Meio Stream Basin, São Paulo State, Brazil were evaluated using major elements as natural tracers. The surface water samples from Meio Stream were collected near the mouth of Meio Stream at the confluence with the Mogi-Guaçu River on February 25, 2005, April 20, 2005, and July 8, 2005. Rainwater samples were collected (using a “bulk” collector) for 1 year at one sampling point located about 4 km from downtown Leme city and other possible sources of contamination. The analyses were performed by pH, temperature, dissolved oxygen, electrical conductivity, total solids, sulfate, nitrate, phosphate, alkalinity, chloride, sodium, calcium, potassium, and magnesium. This basin has serious environmental problems in terms of rainwater and surface water quality, which result in the negative annual flux of cations and anions at Meio Stream Basin, with the exception of chlorine. The Meio Stream, downstream from Leme city, receives several elements/compounds through anthropogenic activities, mainly related to the discharge of domestic effluents. Anthropogenic inputs (mining, fossil fuel burning, and agricultural activities) are responsible for the higher concentrations of cations and anions in the rainwater from this basin.