We assessed the potential of nitrate-nitrogen (NO₃-N) and fluoride (F) contamination in drinking groundwater of an intensively cultivated district in India as a function of its agricultural activities. Three hundred and forty two groundwater samples were collected from different types of wells with varying depths and analyzed for pH, EC, NO₃-N load and F content. Database on predominant cropping system, fertilizer and pesticide uses were also recorded for the district. The NO₃-N load in groundwater samples were low ranging from 0.01 to 5.97 mg L⁻¹ with only 6.7% of them contained greater than 3.0 mg L⁻¹. Samples from the habitational areas showed higher NO₃-N content over the agricultural fields. But all the samples contained NO₃-N below the 10 mg L⁻¹, the threshold limit fixed by WHO for drinking purpose. The content decreased with increasing depth of wells (r = -0.297, P <= 0.01) and increased with increasing rate of nitrogenous fertilizer application (r = 0.931, P <= 0.01) and was higher in areas where shallow-rather than deep-rooted crops are grown. Fluoride content in groundwater was also low (0.02 to 1.19 mg L⁻¹) with only 2.4% of them exceeding 1.0 mg L⁻¹ posing a potential threat of fluorosis in some locality. On average, its content varied little spatially and along depth of sampling aquifers indicating homogeneity in lithology of the district. The content showed a significant positive correlation (r = 0.237, P <= 0.01) with the amount of phosphatic fertilizer (single super phosphate) used for agriculture. Results thus indicated that the groundwater of the study area is presently safe for drinking purpose but some anthropogenic activities associated with intensive cultivation had a positive influence on its loading with NO₃-N and F.

Two advanced models that respectively simulate the transport of heavy metals in the atmosphere at continental and regional scale, as well as the transfer of contaminants in the air-soil-plant system, were used to study the potential accumulation of lead and cadmium in vegetables in a French region submitted to global and local industrial releases. The dynamics of lead and cadmium in the atmosphere, the soil and two types of plants (leaf and fruit vegetables respectively) were simulated over 40 years. Kinetic best estimate calculations were conducted to simulate the potential accumulation of lead and cadmium in soils and plants. An uncertainty analysis was also performed to provide confidence intervals for the maximum contamination levels of leaf and fruit vegetables. A sensitivity analysis allowed to identify the most sensitive parameters of the modeling system. For this purpose, Probability Density Functions were proposed for the main parameters included in the air-soil-plant model. Different results were obtained for lead and cadmium respectively, lead being more sensitive to aerial processes (interception of deposits by leaves eventually followed by translocation to edible organs).

Seasonal deposition fluxes of polycyclic aromatic hydrocarbons (PAHs) in the North Basin of Lake Biwa were investigated by monthly collecting sediment trap samples through a year from July 2003. Average deposition flux of total PAHs was 75 ng cm⁻² year⁻¹, similar to those for other rural area. Deposition fluxes of PAHs did varied seasonally. In the vertical mixing period of the lake, late autumn to early spring, the fluxes of less volatile PAHs were enhanced while those for volatile PAHs were not. The size difference of particles associated with volatile and less volatile PAHs caused the seasonal variation of the fluxes. Oil discharge from water delivery equipments may contribute the fluxes of volatile PAHs in summer to autumn.

The need for solutions to minimize the negative environmental impacts of anthropogenic activities Fhas increased. Sewage sludge is composed of predominantly organic matter and can be used to improve soil characteristics, such as fertility. Therefore, its application in agriculture is an adequate alternative for its final disposal. However, there is a lack of information on its long-term effects on soil changes in tropical areas. Thus, the objectives of this study were to determine (i) the effect of sewage sludge application on heavy metal build-up in soil and maize grains and leaves, and (ii) the effects of soil amendment with sewage sludge on the chemical properties of a Brazilian oxisol. Besides the increasing levels of Zn, Cu, Ni, and Cr, amending soil with sewage sludge also alters the distribution of these metals by increasing the mobile Phases, which correlated significantly with the increase in metal extraction with two single extractants, Mehlich 1 and DTPA (Diethylene triamine pentaacetic acid). The levels of Fe, Mn, Zn, and Cu in maize grains and leaves increased with the type and rate of sewage sludge application. Nevertheless, metal build-up in soil and plants was within the allowed limits. Significant differences were also found in soil characteristics like humic fractionation with the applied sewage doses. The data obtained does not indicate any expressive drawbacks in the use of sewage sludge as a soil amendment, as the heavy metal concentrations observed are unlikely to cause any environmental or health problems, even overestimated loadings, and are in accordance with the Brazilian regulations on farming land biosolid disposal.

The distribution and geochemical behavior of nonylphenol (NP) in suspended and settling particles were studied in Lake Biwa, Japan. The vertical distribution of the particulate nonylphenol (PNP)/particulate organic carbon (POC) ratio showed a characteristic and hitherto unreported profile. The ratio was low at the surface, increased with depth to the middle layer before reaching a maximum at a depth of 45 or 65 m, and decreased toward the bottom. This profile is thought to have been due to the particulate organic matter (POM) in the lake being either freshly produced or aged POM and because the aged POM has a relatively higher affinity for NP compared to freshly produced POM. This idea was supported by the statistical analysis of physicochemical data (PNP, POC and chlorophyll a) and because the average PNP/POC ratio in the aged POM (2.24 x 10⁻⁵ g/g) was approximately four times higher than that of the freshly produced POM (0.63 x 10⁻⁵ g/g). The settling flux was estimated to be 2.2-6.4 μg/m²/day.

The Anllóns basin (NW Spain) has been included in the Natura 2000 Network and declared as Site of Community Importance. The main contamination problems of the basin come from a former gold mine and from agricultural activities, which influence the quality of the sediment-water system. Phosphorus (P) enrichment in the bed sediments was evaluated by analyzing P in the pore waters, in the surface bed sediments, and in the vertical sediment profiles, including both total and bioavailable forms. Two granulometric fractions (<2 mm and <63 μm) were evaluated. Pore waters, bed sediments, and vertical profiles showed high percentages of the bioavailable P fraction with respect to the total P content, which evidences the potential risk of pollution which suppose the bed sediments of the Anllóns River. The vertical profiles showed P enrichment in the superficial layers, which could be the consequence of the increased use of fertilizers in the last decades. With regards to the granulometric distributions, the <63 μm showed, in general, higher P concentrations than the <2 mm fraction. However, at the sampling points most heavily contaminated, the concentration of both fractions becomes similar, thus indicating that, at these sites, the coatings formed over sands can retain important P concentrations in the bed sediments.

Impairment of water quality is a major concern for streams and rivers in the central USA. Total maximum daily loads (TMDLs) establish a watershed framework and set management targets to alleviate pollution from both point and nonpoint sources. For this study, we have used a hydrologic modeling approach to holistically examine the effect of land use management, urban development, and agricultural practices on sediment and nutrient loadings in an agricultural watershed. Annualized Agricultural Nonpoint Source (AnnAGNPS) simulation indicates that while point source dischargers contribute 8% of total nitrogen (TN) and 24% of total phosphorus (TP) loadings to the Marmaton River, agricultural nonpoint sources are the leading pollution source contributing 55% of TN and 49% of TP loading. Based on TMDL analysis and model simulation, 3% of the watershed area (3,244 ha) needs to be targeted to control TN loading whereas 1% of the total area (1,319 ha) is required for TP reduction management. Managing the TN areas alone can achieve a 57% reduction in the TP load required for the TMDL, whereas managing the targeted TP areas can only provide 30% of the required TN reduction. Areas required both TN and TP management comprise 469 ha. Targeting these areas can achieve approximately 22% of the required TN reduction and 29% of the required TP reduction. Overall, 4,094 ha will require management to achieve water quality goals. This study demonstrates that a modeling approach is needed to effectively address TMDL issues and help identify targeted areas for management.

An experimental study to investigate the potential soil accumulation of the triazole fungicide difenoconazole in soil was carried out in northwestern Italy. The fungicide was applied to sugar beet for 4 years with three applications per year at a rate of 75 g ha⁻¹ each, according to formulated product recommended use. Soil cores were collected each year before the first application, after each application and at harvest of the crop. The soil samples were then split into 0-10 and 10-40 cm depth layers, extracted and quantitatively analysed by gas chromatography for difenoconazole residues. The study evidenced that difenoconazole residues could be detected in the upper soil layer only, in quantities detectable after several applications (0.14 to 0.32 mg kg⁻¹ after the third application) which then become undetectable the following year. It can be concluded, therefore, that difenoconazole does not accumulate in soil.

The paper summarizes results of chemical analyses of fog and rime water samples. The samples were collected at Milesovka, the Czech meteorological observatory. The input data set contains the samples acquired during 234 fogs and 14 rime events. The fog and rime samples were collected in the period of 2000-2004. Methods employed for sampling fog and rime water and differences in the pollutant concentrations are described. The following components were analyzed: conductivity, acidity (pH), cations Na⁺, K⁺, NH₄ ⁺, Mg²⁺, Ca²⁺, and anions F⁻, Cl⁻, NO₃ ⁻, SO₄ ²⁻. The attention was exclusively devoted to the precipitation originating in fogs (no falling precipitation particles were considered). Differences in the relative content of selected ions in the annual average samples of rime and fog are presented together with their absolute values. The importance of rime contributions to total precipitation amounts is demonstrated by maximum values of the rime weight detected at the Milesovka Observatory. The absolute maximum of 52.3 kg m⁻² was registered at Milesovka Mt. on December 28, 2002.

Desorption of Cu, Cr, Pb, and Zn from industrially polluted soils as a result of acidification is in focus. The eight soils of the investigation vary greatly in composition and heavy metal concentration/combination. Three soils had elevated concentrations of Cu, Pb, and Zn; regardless of pollution level, pollution origin, and soil type, the order for desorption as pH decreased was Zn > Cu > Pb. Turning to a single heavy metal in different soils, there was a huge difference in the pH at which the major desorption started. The variation was most significant for Pb where, e.g., less than 10% was desorbed at pH 2.5 from one soil, whereas in another soil 60% Pb was desorbed at this pH. Sequential extraction was made and the soils in which a high percentage of Pb was found in the residual phase (adsorbed strongest) was also the soils where less Pb was desorbed at low pH in the desorption experiments. It was evident that Cu, Pb, and Zn started to desorb at a higher pH from calcareous soils than from soils with low carbonate content. The mechanism responsible for this is co-precipitation of heavy metals in the carbonates. When the carbonates are dissolved at a relatively high pH of about 5, the co-precipitated heavy metals are released. The sequential extraction pattern for Cr differed generally much from the other heavy metals since the majority of Cr was extracted in the last two steps. Cr was also the heavy metal that desorbed the least at high acidification.