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101.
This work deals with disposal of slurries generated during the cutting and polishing processes of slabs of decorative sedimentary
carbonate rocks in the north western Sicily. At present, they are used as fillers of dismantled quarries near the sawmills
and, as a final step of reclamation, are covered with earth layers. In spite of such inexpensive solution, there is lack of
knowledge about the composition of the waste. In order to assess if there is any threat for the environment and to suggest
indications for alternative solutions, such as recycling or inactivation processes, the slurries were analysed by XR diffraction,
simultaneous thermal analysis, ICP/MS, ionic chromatography, FTIR, UV-Vis, COD and TOC measurements, grain size analysis.
Results indicate that the slurries can threaten the groundwater, because of the high chemical oxygen demand; furthermore they
can modify the mechanism of groundwater recharge, because of their grain size distribution. Some laboratory tests show that,
even in very aggressive conditions, the solid pollutants persist in the waste and slowly release into water the products of
their degradation. The slurry therefore should be subjected to inactivation treatment before disposal or, alternatively, recycled
as secondary raw material for a suitable process. 相似文献
102.
Eleven surface soil samples from calcareous soils of industrial areas in Hamadan Province, western Iran were analyzed for
total concentrations of Zn, Cd, Ni, Cu and Pb and were sequentially extracted into six fractions to determine the bioavailability
of various heavy metal forms. Total Zn, Cd, Ni, Cu and Pb concentrations of the contaminated soils were 658 (57–5,803), 125.8
(1.18–1,361), 45.6 (30.7–64.4), 29.7 (11.7–83.5) and 2,419 (66–24,850) mg kg−1, respectively. The soils were polluted with Zn, Pb, and Cu to some extent and heavily polluted with Cd. Nickel values were
not above regulatory limits. Copper existed in soil mainly in residual (RES) and organic (OM) fractions (about 42 and 33%,
respectively), whereas Zn occurred essentially as RES fraction (about 69%). The considerable presence of Cd (30.8%) and Pb
(39%) in the CARB fraction suggests these elements have high potential biavailability and leachability in soils from contaminated
soils. The mobile and bioavailable (EXCH and CARB) fractions of Zn, Cd, Ni, Cu, and Pb in contaminated soils averaged (7.3,
40.4, 16, 12.9 and 40.8%), respectively, which suggests that the mobility and bioavailability of the five metals probably
decline in the following order: Cd = Pb > Ni > Cu > Zn. 相似文献
103.
R. K. Prasad N. C. Mondal Pallavi Banerjee M. V. Nandakumar V. S. Singh 《Environmental Geology》2008,55(3):467-475
Remote Sensing and Geographic Information System has become one of the leading tools in the field of hydrogeological science,
which helps in assessing, monitoring and conserving groundwater resources. It allows manipulation and analysis of individual
layer of spatial data. It is used for analysing and modelling the interrelationship between the layers. This paper mainly
deals with the integrated approach of Remote Sensing and geographical information system (GIS) to delineate groundwater potential
zones in hard rock terrain. The remotely sensed data at the scale of 1:50,000 and topographical information from available
maps, have been used for the preparation of ground water prospective map by integrating geology, geomorphology, slope, drainage-density
and lineaments map of the study area. Further, the data on yield of aquifer, as observed from existing bore wells in the area,
has been used to validate the groundwater potential map. The final result depicts the favourable prospective zones in the
study area and can be helpful in better planning and management of groundwater resources especially in hard rock terrains. 相似文献
104.
The aim of this interdisciplinary study is to examine a component of the hydrological cycle in Galapagos by characterizing
soil properties. Nine soil profiles were sampled on two islands. Their physical and hydrodynamic properties were analyzed,
along with their mineralogical composition. Two groups of soils were identified, with major differences between them. The
first group consists of soils located in the highlands (>350 m a.s.l.), characterized by low hydraulic conductivity (<10−5 m s−1) and low porosity (<25%). These soils are thick (several meters) and homogeneous without coarse components. Their clay fraction
is considerable and dominated by gibbsite. The second group includes soils located in the low parts of the islands (<300 m
a.s.l.). These soils are characterized by high hydraulic conductivity (>10−3 m s−1) and high porosity (>35%). The structure of these soils is heterogeneous and includes coarse materials. The physical properties
of the soils are in good agreement with the variations of the rainfall according to the elevation, which appears as the main
factor controlling the soil development. The clayey alteration products constrain soils physical and hydrodynamic properties
by reducing the porosity and consequently the permeability and also by increasing water retention. 相似文献
105.
The Cu–Co–Ni Texeo mine has been the most important source of Cu in NW Spain since Roman times and now, approximately 40,000 m3 of wastes from mine and metallurgical operations, containing average concentrations of 9,263 mg kg−1 Cu, 1,100 mg kg−1 As, 549 mg kg−1 Co, and 840 mg kg−1 Ni, remain on-site. Since the cessation of the activity, the abandoned works, facilities and waste piles have been posing
a threat to the environment, derived from the release of toxic elements. In order to assess the potential environmental pollution
caused by the mining operations, a sequential sampling strategy was undertaken in wastes, soil, surface and groundwater, and
sediments. First, screening field tools were used to identify hotspots, before defining formal sampling strategies; so, in
the areas where anomalies were detected in a first sampling stage, a second detailed sampling campaign was undertaken. Metal
concentrations in the soils are highly above the local background, reaching up to 9,921 mg kg−1 Cu, 1,373 mg kg−1 As, 685 mg kg−1 Co, and 1,040 mg kg−1 Ni, among others. Copper concentrations downstream of the mine works reach values up to 1,869 μg l−1 and 240 mg kg−1 in surface water and stream sediments, respectively. Computer-based risk assessment for the site gives a carcinogenic risk
associated with the presence of As in surface waters and soils, and a health risk for long exposures; so, trigger levels of
these elements are high enough to warrant further investigation. 相似文献
106.
Paul F. Hudak 《Environmental Geology》2008,55(6):1311-1317
This modeling study evaluated the capability of alternative funnel-and-gate structures with three gates for capturing contaminated
groundwater in a hypothetical unconfined aquifer. Simulated interceptor structures were linear and 45 m wide, consisting of
three gates and two funnels (walls). One gate occupied the center and two gates occupied the ends of the interceptor structures.
The structures, positioned perpendicular to regional groundwater flow, traversed the entire thickness of the aquifer. A total
of four structures were evaluated (numbers designate widths of end, center, and end gates, respectively, in meters): 3-3-3,
2-5-2, 1-7-1, and 4-1-4. Particle tracking and zonal water budgets identified shapes of capture zones and discharge patterns
for each interceptor structure. A mass transport model, accounting for advection and hydrodynamic dispersion, tested the capability
of each structure for capturing a contaminant plume. Results suggest that: time-dependent capture zones underestimate the
amount of time to capture a contaminant plume, wide center gates facilitate plume capture, and wide end gates facilitate lateral
containment of contaminants. Of the structures simulated, the 2-5-2 configuration was relatively efficient at processing and
containing the simulated contaminant plume. 相似文献
107.
Regional distribution pattern of groundwater heavy metals resulting from agricultural activities 总被引：18，自引：0，他引：18
Contaminations of groundwater by heavy metals due to agricultural activities are growing recently. The objective of this study
was to evaluate and map regional patterns of heavy metals (Cd, Zn and Cu) in groundwater on a plain with high agricultural
activities. The study was conducted to investigate the concentration of heavy metals and distribution in groundwater in regions
of Shush Danial and Andimeshk aquifers in the southern part of Iran. Presently, groundwater is the only appropriate and widely
used source of drinking water for rural and urban communities in this region. The region covers an area of 1,100 km2 between the Dez and Karkhe rivers, which lead to the Persian Gulf. For this study, the region was divided into four sub-regions
A, B, C and D. Additionally, 168 groundwater samples were collected from 42 water wells during the earlier months of 2004.
The flame atomic absorption spectrometry (AAS-Flame) was used to measure the concentration of heavy metals in water samples
and the Surfer software was used for determination of the contour map of metal distribution. The results demonstrated that
in all of the samples, Cd and Zn concentrations were below the EPA MCLG and EPA secondary standard, respectively. However,
the Cu contents of 4.8 % of all samples were higher than EPA MCL. It is also indicated that the concentrations of metals were
more pronounced at the southern part of the studied region than at the others. The analysis of fertilizers applied for agricultural
activities at this region also indicated that a great majority of the above-mentioned heavy metals were discharged into the
environment. Absence of confining layers, proximity to land surface, excess agricultural activities in the southern part and
groundwater flow direction that is generally from the north to the southern parts in this area make the southern region of
the Shush plain especially vulnerable to pollution by heavy metals than by other contaminants. 相似文献
108.
A Triassic carbonate unit has been intensively drained by zinc and lead ore mines and numerous borehole fields since the nineteenth
century. Its groundwater recharge has increased due to: pumping of water from boreholes, mining activity, and urbanization.
An approach to determine the amounts of the recharge at a variety of spatial scales is presented in the paper. Different methods
were used to identify and quantify recharge components on a regional and local scale: mathematical modelling was performed
for four aquifers included in an aquifer system, an analytical estimation based on the assumption that an average recharge
is equal to the average discharge of the hydrogeological system—for six man-made drainage centres, and the method of water
level fluctuation (WLF) was applied in one observation borehole. Results of modelling have been supplemented by observation
of environmental tracers (δ18O, δ2H, 3H), noble gases temperatures, and 4Heexc in groundwater. The regional aquifer’s current recharge according to estimations performed by means of modelling varies from
39 to 101 mm/year on average. Depending on the aquifer site the average precipitation ranges from 779 to 864 mm/year. In the
confined part of the aquifer average recharge ranges from 26 to 61 mm/year. Within outcrops average recharge varies from 96
to 370 mm/year. Current recharge estimated by the analytical method for man-made drainage centres varies from 158 up to 440 mm/year.
High values are caused by different recharge sources like precipitation, induced leakage from shallow aquifers, and water
losses from streams, water mains and sewer systems. Pumping of water, mining and municipal activities constitute additional
factors accounting for the intensified recharge. 相似文献
109.
M. M. Jordán S. Pina F. García-Orenes M. B. Almendro-Candel E. García-Sánchez 《Environmental Geology》2008,55(2):453-462
The ecologic restoration criteria in areas degraded from extraction activities require making use of their mine spoils. These
materials do not meet fertility conditions to guarantee restoration success and therefore, need the incorporation of organic
amendments to obtain efficient substratum. Reducing the deficiencies in the organic material and restoration material nutrients
with the contribution of treated sewage sludge is proposed in this work. This experiment was based on a controlled study using
columns. The work was conducted with two mine spoils, both very rich in calcium carbonate. The first mineral, of poor quality,
came from the formation of aggregates of crushed limestone (Z). The other residual material examined originated in limestone extraction, formed by the levels of interspersed non-limestone
materials and the remains of stripped soils (D). Two treatments were undertaken (30,000 and 90,000 kg/ha of sewage sludge), in addition to a control treatment. The water
contribution was carried out with a device that simulated either short-duration rain or a flooding irrigation system in order
to cover the surface and then percolate through the soil. The collection of leached water took place 24 h after the applications.
Different parameters of the leached water were determined, including pH, electrical conductivity, nitrate anions, ammonium,
phosphates, sulphates and chlorides. The values obtained for each irrigation application are discussed, and the nitrate values
obtained were very elevated. 相似文献
110.