Water, acid ground

Limits of detection for each of the six soil metabolites in surface water and ground-water were determined by using an estimate of variability for the 0.25 pgL fortifications from samples analyzed along with hundreds of surface water and groundwater sets during the years 1999-2001. During these years, the estimated LODs were below 0.1 ug for acetochlor sulfonic acid, acetochlor oxanilic acid, alachlor oxanilic acid, metolachlor sulfonic acid, and metolachlor oxanilic acid and about 0.1 igL for alachlor sulfonic acid. If the actual concentration of an analyte is at this detection limit or greater, there is at least a 95% chance of detection. 

The carbonic acid thus formed is rich in oxygen-16. The mildly acid ground-water as well as the water of rivers and lakes, which is, therefore, also enriched in oxygen-16, dissolves limestone from surrounding rocks, to form calcium bicarbonate, which is soluble in water ... 

During preparations for blasting the sulfide mineral copper pyrites, ammonium nitrate-based blasting cartridges exploded prematurely in the blast holes. This was attributed to exothermic interaction of acid ground-water with the sulfide-oxidant combination. 

Herbert Jr, R.B. (1995) Precipitation of Fe oxy-hydroxides and jarosite from acidic ground-water. GFF 117 81-85... 

Herbert Jr, R.B. (1996) Metal retention by iron oxide precipitation from acidic ground water in Dalama, Sweden. Appl. Geochem. 11 229-235... 

Abbreviations used HO, Lake Hohloh ABV, wastewater effluent BS1, soil seepage water FG1, ground-water numbers, sampling occasion FA, fulvic acid HA, humic acid K, sample concentrate gained after ultrafiltration. 

Heron, G., M.J. Barcelona, M.L. Andersen, and T.H. Christensen. 1997. Determination of nonvolatile organic carbon in aquifer solids after carbonate removal by sulfurous acid. Ground Water 35 6-11. 

Cravotta C. A., Ill (1994) Secondary iron sulfate minerals as sources of sulfate and acidity-the geochemical evolution of acidic ground water at a reclaimed surface coal mine in Pennsylvania. In Environmental Geochemsitry of Sulfide Oxidation (eds. C. N. Alpers and D. W. Blowes). American Chemical Society, Washington, DC, vol. 550, pp. 345-364. 

Morin, K. A., Cheery, J. A., Dave, N. K Lim, T. P and Vivyurka, A. J., 1988. Migration of acidic ground water seepage from uranium-tailings impoundments. 1. Field study and conceptual hydrogeochemical model. J. Contaminant Hydrology, v. 2, pp. 271-303. 

Zhu, C., Hu, F. Q., and Burden, D. S., 2001a, Multi-component reactive transport modeling of natural attenuation of an acid ground water plume at a uranium mill tailings site. J. Contaminant Hydrology, v. 52, pp. 85-108. 

Few samples in the real world can be analyzed without some chemical or physical preparation. The aim of aU sample preparation is to provide the analyte of interest in the physical form required by the instrument, free of interfering substances, and in the concentration range required by the instrument. For many instruments, a solution of analyte in organic solvent or water is required. We have already discussed some of the sample preparation steps that may be needed. Solid samples may need to be cmshed or ground, or they may need to be washed with water, acid, or solvent to remove surface contamination. Liquid samples with more than one phase may need to be extracted or separated. Filtration or centrifugation may be required. 

The stabihzing H COj source in this case is CO. Increase in the solution alkalinity results in expending of the carbonic acid, which is compensated by additional dissolution of CO. On the contrary, increase in acidity causes generation of excess carbonic acid, which turns into CO and leaves the solution. This buffer is typical of the ground waters in contact with unlimited source of CO and maintains sufficiently high water acidity with pH in the range of 5.4-7A. 

The hydrated components (C-S-H, portlandite, sulfoaluminates) in the cement matrix of concrete are in equilibrium with the pore liquid that is characterized by a high pH, due to the presence of OH (balanced by Na and K ). When concrete comes into contact with acid solutions, these compounds may dissolve at a rate that depends on the permeability of the concrete, the concentration and the type of acid. In soil with acidic ground water, the rate of refreshing is important Acids that can attack concrete are sulfuric acid, hydrochloric acid, nitric acid, organic acids such as acetic acid and humic adds and solutions of CO2. The rate of attack on the cement matrix depends on the solubility of the salts that are formed... 

In the biosphere, rain that is not lost back to the atmosphere by evaporation from the ground or from trees may pass deep underground, only to emerge at a much later date (Table 2.27) in a river or lake. Water coming into contact with rocks (and derived soils) reacts with primary minerals contained in them. The minerals dissolve to varying extents, and some of the dissolved constituents react with one another to form new, secondary minerals. Dissolution is mainly controlled by the water acidity provided from plant mineralization (humic acids), atmospheric carbonic acid and acid rain . The overall process is called chemical weathering (see Chapter 2.2.2.5, Eqs. 2.62 and 2.62 Berner and Berner 1996). 

A steel reinforced concrete pile foundation must consider the effect of sulfates, groimd water or seawater, chlorides in sods, chemical waste, acidic ground water, and organic acids. 

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