One-step immunochromatographic assay (ICA) has been developed using colloidal gold-labeled monoclonal antibody probe for the rapid detection of lead ions in water samples. The ICA was based on the theory of competitive reactivity, and the results can be easily judged based on the presence or absence of a red colored test line with visual detection. Under optimal conditions, this method shows high detecting sensitivity with a LOD (limit of detection) of 50 ng/ml. Stability test indicates that the immunochromatographic strips are stable for 8 weeks at room temperature. During practical application, nanometer TiO2 is used to enrich the lead ions in water samples. The ICA is successfully applied in the measurement of lead ion concentrations in local water samples, and the results are highly consistent with that of ICP-MS. Detecting lead ions with ICA can be done within 4 min and is very useful for the rapid onsite testing.

Samples of airborne particulate matter (PM₂.₅) were collected at a site in Lahore, Pakistan from November 2005 to January 2006. A total of 129 samples were collected using an Andersen Reference Ambient Air Sampler 2.5-400 sampler and analyzed for major ions, trace metals, and organic and elemental carbon concentrations. The data set was then analyzed by positive matrix factorization (PMF) to identify the possible sources of the atmospheric PM collected in this urban area. Six factors reproduced the PM₂.₅ sample compositions with meaningful physical interpretation of the resolved factors. The sources included secondary PM, diesel emissions, biomass burning, coal combustion, two-stroke vehicle exhaust, and industrial sources. Diesel and two-stroke vehicles contributed about 36%, biomass burning about 15%, and coal combustion sources around 13% of the PM₂.₅ mass. Nearly two thirds of the PM₂.₅ mass is carbonaceous material. Secondary particles contributed about 30% of PM₂.₅ mass. The conditional probability function (CPF) was then used to help identify likely locations of the sources present in this area. CPF analysis point to the east and northeast, which are directions of urban and industrial areas located across the border near Amritsar, India as the most probable source for high PM₂.₅ concentration from diesel and two-stroke vehicles exhaust in Lahore. Analysis of those days within three different ranges of PM₂.₅ concentration shows that most of the measured high PM₂.₅ mass concentrations were driven by diesel and two-stroke vehicle emissions including the associated primary sulfate. The use of the potential source contribution function (PSCF) to find the source locations of regionally transported particles is inapplicable in situations when high PM₂.₅ concentrations are dominated by local sources and local meteorology.

In this work, we evaluated the effect of harmful ecotoxins, 4,5,6-trichloroguaicol (4,5,6-TCG) and tetrachloroguaiacol (TeCG), on the oxidation of the fluorescent probe dihydrorhodamine 123, the content of free phenols and the level of the total, oxidized and reduced glutathione in the leaves of reed canary grass (Phalaris arudinacea). Furthermore, the effect on the activity of guaiacol peroxidase and glutathione S-transferase was investigated. Both 4,5,6-TCG and TeCG increased the activity of guaiacol peroxidase and glutathione S-transferase, they also elevated the content of free phenols and the level of the total glutathione. A stronger effect was exerted by tetrachloroguaiacol, which strongly increased the level of the total glutathione and the content of free phenols on the 3rd and 6th day of the experiment. The activity of glutathione S-transferase was more intensively induced by trichloroguaiacol. Both 4,5,6-TCG and TeCG oxidized dihydrorodamine 123 and the effect was stronger in the presence of magnesium ions.

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.

Electrocoagulation (EC) has been evaluated as a treatment technology for arsenic (As) removal. Experiments were developed in an electrochemical reactor with three parallel iron plates. Current densities of 15, 30, and 45 A m⁻² were used to treat model water and 45 A m⁻² to treat underground water (GW). For both types of water, the EC process was able to decrease the residual arsenic concentration to less than 10 μg L⁻¹. However, the treatment time for As removal from GW was higher. This phenomenon was attributed to the competition of dissolved species present in GW such as silica and calcium with arsenic for the adsorption sites on the ferric oxyhydroxides flocs generated during the EC process. A procedure is proposed to reduce such interference by the addition of a silica adsorption inhibitor compound into the GW achieving a reduction in the process time. The adsorption of arsenic species over adsorbent was found to follow Lagergren adsorption model.

In the evaluation of the risk of pesticide leaching to groundwater, the soil surface is usually assumed to be level, although important crops like potato are grown on ridges. A fraction of the water from rainfall and sprinkler irrigation may flow along the soil surface from the ridges to the furrows, thus bringing about an extra load of water and pesticide on the furrow soil. A survey of the literature reveals that surface-runoff from ridges to furrows is a well-known phenomenon but that hardly any data are available on the quantities of water and pesticide involved. On the basis of a field experiment with additional sprinkler irrigation, computer simulations were carried out with the Pesticide Emission Assessment at Regional and Local scales model for separate ridge and furrow systems in a humic sandy potato field. Breakthrough curves of bromide ion (as a tracer for water flow) and carbofuran (as example pesticide) were calculated for 1-m depth in the field. Bromide ion leached comparatively fast from the furrow system, while leaching from the ridge system was slower showing a maximum concentration of about half of that for the furrow system. Carbofuran breakthrough from the furrow system began about a month after application and increased steadily to substantial concentrations. Because the transport time of carbofuran in the ridge soil was much longer, no breakthrough occurred in the growing season. The maximum concentration of carbofuran leaching from the ridge-furrow field was computed to be a factor of six times as high as that computed for the corresponding level field. The study shows that the risk of leaching of pesticides via the furrow soil can be substantially higher than that via the corresponding level field soil.

The Nandong Underground River System (NURS) is located in Southeast Yunnan Province, China. Groundwater in NURS plays a critical role in socio-economical development of the region. However, with the rapid increase of population in recent years, groundwater quality has degraded greatly. In this study, the analysis of 36 groundwater samples collected from springs in both rain and dry seasons shows significant spatial disparities and slight seasonal variations of major element concentrations in the groundwater. In addition, results from factor analysis indicate that NO ₃ ⁻ , Cl⁻, SO ₄ ²⁻ , Na⁺, K⁺, and EC in the groundwater are mainly from the sources related to human activities while Ca²⁺, Mg²⁺, HCO ₃ ⁻ , and pH are primarily controlled by water-rock interactions in karst system with Ca²⁺ and HCO ₃ ⁻ somewhat from anthropogenic inputs. With the increased anthropogenic contaminations, the groundwater chemistry changes widely from Ca-HCO₃ or Ca (Mg)-HCO₃ type to Ca-Cl (+NO₃) or Ca (Mg)-Cl (+NO₃), and Ca-Cl (+NO₃+SO₄) or Ca (Mg)-Cl (+NO₃+SO₄) type. Concentrations of NO ₃ ⁻ , Cl⁻, SO ₄ ²⁻ , Na⁺, and K⁺ generally show an indistinct grouping with respect to land use types, with very high concentrations observed in the groundwater from residential and agricultural areas. This suggests that those ions are mainly derived from sewage effluents and fertilizers. No specific land use control on the Mg²⁺ ion distribution is observed, suggesting Mg²⁺ is originated from natural dissolution of carbonate rocks. The distribution of Ca²⁺ and HCO ₃ ⁻ does not show any distinct land use control either, except for the samples from residential zones, suggesting the Ca²⁺ and HCO ₃ ⁻ mainly come from both natural dissolution of carbonate rocks and sewage effluents.

The elevated water table (EWT) technique for preventing acid mine drainage (AMD) was tested using instrumented laboratory columns containing reactive tailings from the Louvicourt and Sigma mines, Abitibi, Quebec. The tests were performed in short (0.4 m) and long (1.4-1.7 m) columns over 400-500 days and included periodic surface recharge and subsequent monitoring of the leached drainage water. In each column, the water table depth was adjusted relative to the air entry value (AEV or ψa) of the tailings. The influence of different water table elevations was evaluated by measuring the effluent pH, as well as the concentrations of major ions including sulphate, iron, zinc, copper and lead. Provided the water table depth below the tailings surface remained less than one half of the tailings' AEV, the observed data showed that an EWT can be very effective in reducing acid mine drainage. The principal factors controlling drainage quality were the saturated hydraulic conductivity (k sat) and the air entry value (ψa) of the tailings. A lower k sat and a higher ψa in the tailings tend to increase the performance of an elevated water table by limiting drainage-induced desaturation. Mineralogical composition had relatively little effect on the hydrogeochemical evolution provided the tailings remained highly saturated (S r ≥ 90%). The results presented here indicate that an elevated water table can be an effective means for controlling the production of AMD when the design conditions are properly selected and applied.

In the present work the kinetics of ferric reduction was investigated using dissimilatory ferric- and sulphate-reducing bacterial cultures. The effect of sulphate reduction on Fe(III) reduction was also studied. The study is an attempt to improve the biological reduction rate of Fe(III) as an alternative biotechnological way to the reduction step in steelmaking processing operations. The results obtained show that the reduction of ferric iron and sulphate took place in a successive way and none synergetic effect was detected. The simultaneous action of both metabolic activities did not enhance the process but slowed down the kinetics of ferric reduction. The reduction process of 3 g/L of soluble ferric and 3 g/L of sulphate lasted 25 days. Ferric iron was the first electron acceptor to be reduced in the first 15 days followed by the sulphate reduction in the following 10 days. That result suggests that ferric reduction is a preferential metabolic process over sulphate reduction when both electron acceptors coexist. None improvement in the kinetics was observed using an electron donor concentration in excess. In contrast, the total reduction of ferric ion (3 g/L) with adapted bacterial cultures was achieved in only 36 h. The presence of sulphate had no effect on the ferric reduction. Finally, an improved culture medium for ferric-reducing bacteria is also proposed.

A study on pH and chemical composition of precipitation was carried out in two Italian sites, one urban (site 1) and one rural (site 2), located approximately 30 km far from Bologna, during a 3-year period. No significative site variation was found. In both locations, bulk deposition pH ranged from slightly acid to slightly alkaline, despite the volume weighted mean concentration of acidic species, NO ₃ ⁻ and SO ₄ ²⁻ (67.4 and 118.4 μeq l⁻¹ in site 1 and 88.7 and 103.8 μeq l⁻¹ in site 2), that were similar to those of typical acidic rainfall region. This might be ascribed to the neutralization reaction of the Ca²⁺, attributed to the calcareous soil and the frequent dusty air mass intrusion from the Sahara. The pair correlation matrix and the analysis of the main components suggested also ammonium and other crustal elements as neutralization agents. The depositional rate of SO ₄ ²⁻ and NO ₃ ⁻ , chemical elements of agricultural interest, amounted to 38 and 28 and 32 and 35 kg ha⁻¹ for site 1 and site 2, respectively. These supplies of nutrient were not negligible and had to be considered on cultivated lands. NH ₄ ⁺ deposition rate on site 2 was 7 kg ha⁻¹, 23% over site 1, probably due to nitrogen fertilization in the fields around the monitoring station. In site 1, SO ₄ ²⁻ presented a seasonal trend, indicating that its principal source was the residential heating. Results emphasized that the entity of the bulk deposition acidification is linked not only to the ions local emission sources (fossil fuel combustions, heating, and fertilizers) but also to the surrounding territory and the prevalent wind that transports through kilometers air masses which may contain acidic and alkaline species.