Water seepage

The background of this study is the investigation at the site Bielatal (see Daus et al. this volume). The arsenic concentrations in the seepage water of this tailings pond are high (up to 4 mg/1) and natural arsenic precipitation processes are incomplete. The neutral pH, the presence of both arsenite and arsenate (sum 1 mg/L), and the oxygen saturation of the water are the boundary conditions of the described experiments. 

The aim of this work was to investigate the arsenic mobilization from the tailings material (200 - 500 pg/g As) into the seepage water (up to 3.5 mg/L As) and the process of seepage water effluent forming an immobilized precipitate (up to 8 % As) in the creek. Different analytical methods for the determination of total concentrations and different sequential extraction methods as well as hyphenated techniques for speciation analysis were applied to follow the way of the arsenic in this environment. 

Figure 1. Differences between filtered and unfiltered samples from the seepage water...

The mobilization of arsenic from the tailings material seems to be a slow and continuos process attributed to reduction of iron phases. The seepage water of the middle source contains arsenite as well as arsenate in high concentrations and seems to be the only water source in contact with the tailings material. The concentrations of arsenic downstream are still high and the immobilization process by precipitation of iron hydroxide and coprecipitation or sorption of arsenic is incomplete. A reason for this may be the slow kinetics of the oxidation process and the transport of fine grained hydroxide particles. These particles are mobile and can bind the arsenic (mainly as arsenate) too. 

Due to the various health risks of different element species, there are a multitude of applications for natural water samples in this field (e.g., Cr and Sb speciation or Br and I determination).19 The investigation of heavy metal complexes with humic substances by isotope dilution SEC-ICP-MS has been described, for example, by McSheehy and Mester.20 Copper, zinc and molybdenum were found to form complexes with similar size fractions of humic substances in seepage water samples from soils. Sturgeon s group proposed the use of solid phase microextraction (SPME)... 

Seepage waters from climax stock (quartz monzonite). 

Vollmuth, S. and Niessner, R., Degradation of PCDD, PCDF, PAH, PCB, and chlorinated phenols during the destruction-treatment of landfill seepage water in laboratory model reactor (UV, ozone, and UV/ozone), Chemosphere, 30, 2317-2331, 1995. 

Vollmuth, S., Wenzel, A., and Niessner, R., Purification of organic contaminants in seepage water of a landfill by UV/ ozone technique, Proc. SPIE, 2504, 520-530, 1995. 

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. 

Oil pollution TT seepage water, whole sediment I,I (Wemersson, 2004)... 

Seepage water (rich The acidification with 0.01 mol 1, 1 H3P04 6 days 31... 

Calculate the composition of seepage water with and without considering evaporation assuming that the annual average precipitation in an area is 250 mm, the current evaporation is 225 mm and the surface runoff is 20 mm. Use the rainwater analysis of exercise chapter 3.1.2.1. Furthermore, there is an increased C02 partial pressure of 0.01 bar in the unsaturated zone. This unsaturated zone consists mainly of limestone and sandstone. 

What is the chemical composition of the seepage water discharging at the foot of the heap along the base sealing ... 

Infiltrating rainwater now dissolves C02 according to the increased partial pressure of 1 Vol% in the unsaturated zone. Thus, the seepage water has the following characteristics pH 4.76... 

Exposure Levels in Environmental Media. Tetryl has been detected in seepage water, groundwater, and surface and subsurface soil at military installations (Army 1980, 1981b, 1986a, 1988, 1990b ATSDR 1987 HazDat 1994). More data are needed regarding levels of tetryl in surface water, groundwater, soil, and air in and around these sites. Quantitative information is needed to assess the potential for human exposure and to better identify exposed populations. 

---