Compositional Data for Bengal Delta Sed

Collected from Boreholes at Srirampur,

Kachua, Bangladesh

Open-File Report 2006-1222

U.S. Department of the Interior

U.S. Geological Survey
In cooperation with the Geological Survey of Bangladesh and Bangladesh Water 

Development Board 

Compositional Data for Bengal Delta Sediment Collected 

from Boreholes at Srirampur, Kachua, Bangladesh 

By George N. Breit, James C. Yount, Md. Nehal Uddin, Ad. Atual Muneem, Heather A. Lowers, Rhonda L. 

Driscoll, and John W. Whitney 

Open-File Report 2006–1222 

U.S. Department of the Interior 

U.S. Geological Survey 
U.S. Department of the Interior 

DIRK KEMPTHORNE, Secretary 

U.S. Geological Survey 

P. Patrick Leahy, Acting Director 

U.S. Geological Survey, Reston, Virginia 2006 

Revised and reprinted: 2006 

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Suggested citation: 

Breit, G.N., Yount, J., Uddin, Md. N., Muneem, Ad., A., Lowers, H., Driscoll, R.,, and Whitney, J.W., 2006, 

Compositional data for Bengal delta sediment collected from boreholes at Srirampur, Kachua, Bangladesh: 

U.S. Geological Survey Open-file Report 2006-1222 

Any use of trade, product, or firm names is for descriptive purposes only and does not imply 

endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report. 

ii
Contents 

Abstract ...................................................................................................................................................................................1

Introduction.............................................................................................................................................................................1 

Setting...............................................................................................................................................................................2

Methods...................................................................................................................................................................................2 

Sample collection ...........................................................................................................................................................2 

Grain-size analysis .........................................................................................................................................................4 

Mineralogy.......................................................................................................................................................................4 

Bulk Chemical Analyses ................................................................................................................................................4 

Extraction Chemical Analyses......................................................................................................................................4 

Results......................................................................................................................................................................................7 

Physical and Mineralogical Characteristics .............................................................................................................7 

Bulk Chemical Composition ..........................................................................................................................................7 

Chemical Extractions ...................................................................................................................................................11 

References Cited..................................................................................................................................................................13 

 Figures 

1. Location of Srirampur, Bangladesh ............................................................................................................................3 

2. Ternary diagram of sand, silt, and clay abundances...............................................................................................7 

3. Comparison of measured and corrected sulfur concentrations ...........................................................................9 

Tables 

1. Median, minimum and maximum concentrations. .................................................................................................10

Appendices 

1. Depth and description of air-dried sediment samples............................................................................................16 

2. Depth and description of preserved sediment samples.........................................................................................18 

3. Results of grain-size analysis ......................................................................................................................................20 

4. Major minerals present in air-dried sediment samples as determined by X-ray diffraction...........................22 

5. Results of quantitative mineralogical analysis of air-dried sediments using X-ray diffraction ......................24 

6. Results of carbon and sulfur analysis of air-dried samples...................................................................................25 

7. Results of ICP-AES analyses of air-dried samples..................................................................................................27 

8. Results of EDXRF analysis of air-dried samples.......................................................................................................33 

9. Results of arsenic analyses by HGAAS of air-dried samples................................................................................39 

10. Concentrations of major cations extracted with 0.1 M SrCl2 ................................................................................40 

11. Total iron and ferrous iron extracted by 0.5 N HCl from air-dried sediment samples......................................41

12. Total iron and ferrous iron extracted by 0.5 N HCl from preserved sediment samples...................................42 

13. Results of analyses of 0.5 N HCl extract solutions from preserved sediment samples...................................43 

14. Results of analyses of Ti(III) -EDTA extract solutions from preserved sediment samples .............................49 

15. Concentration of arsenic extracted using H2

O2 and HCl........................................................................................50

16. Concentrations of AVS, Acid-soluble Sulfate, and Reducible Sulfide ................................................................51 

iii
SI to Inch/Pound 

Multiply By To obtain 

Length 

centimeter (cm) 0.3937 inch (in.) 

millimeter (mm) 0.03937 inch (in.) 

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi) 

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Volume 

milliliter 0.03382 ounce, fluid (fl. oz) 

milliliter 0.002113 pint (pt) 

milliliter 0.001057 quart (qt) 

milliliter 0.06102 cubic inch (in3) 

Mass 

gram (g) 0.03527 ounce, avoirdupois (oz) 

kilogram (kg) 2.205 pound avoirdupois (lb) 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: 

°F=(1.8×°C)+32 

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: 

°C=(°F-32)/1.8 

Horizontal coordinate information is referenced to World Geodetic System 1984 (WGS 84) 

iv
Chemical Symbols 

Abbreviation Chemical Species 

Ag silver 

Al aluminum 

As arsenic 

Au gold 

B boron 

Ba barium 

Be beryllium 

Bi bismuth 

C carbon 

C-total total carbon 

C-carbonate carbonate carbon 

Ca calcium 

Cd cadmium 

Ce cerium 

Co cobalt 

Cs cesium 

EDTA ethylene diamine tetra-acectic acid 

Er erbium 

Fe iron 

Ga gallium 

Ge germanium 

Ho holmium 

K potassium 

La lanthanum 

Li lithium 

Mg magnesium 

Mn manganese 

Mo molybdenum 

Na sodium 

Nb niobium 

Nd neodymium 

Ni nickel 

P phosphorous 

Pb lead 

Rb rubidium 

S sulfur 

Sb antimony 

Se selenium 

Sn tin 

Sr strontium 

v
Abbreviation Chemical Species 

Ta tantalum 

Th thorium 

Ti titanium 

U uranium 

V vanadium 

W tungsten 

Y yttrium 

Yb ytterbium 

Zn zinc 

Zr zirconium 

vi
Compositional Data for Bengal Delta Sediment 

Collected from Boreholes at Srirampur, Kachua, 

Bangladesh 

By George N. Breit, James C. Yount, Md. Nehal Uddin, Ad. Atual Muneem, Heather A. Lowers, 

Rhonda L. Driscoll, and John W. Whitney 

Abstract 

Processes active within sediment of the Bengal delta have attracted world concern because 

of the locally high content of arsenic dissolved in ground water drawn from that sediment. 

Sediment samples were collected from two boreholes in Srirampur village, Kachua upazila, 

Chandphur district, Bangladesh, to investigate the processes contributing to arsenic contamination. 

The samples were mineralogically and chemically analyzed to determine compositional variations 

related to the arsenic content of the sediment. Mineralogy of the sediments was determined using 

powder X-ray diffraction. Bulk chemical composition was measured by Combustion, Inductively 

Coupled Plasma Atomic Emission Spectroscopy, Energy Dispersive X-ray Fluorescence, and 

Hydride Generation Atomic Absorption Spectrophotometry. Solutions produced by four chemical 

extractions — 0.1 molar strontium chloride, 0.5 normal hydrochloric acid, titanium(III)-EDTA, and 

a solution of hydrogen peroxide and hydrochloric acid — were analyzed to evaluate the chemical 

reactivity of the sediment with an emphasis on arsenic residence. Acid-volatile sulfide, acidsoluble sulfate, and reducible sulfide were also measured. 

Sediment sampled at Srirampur is typically unlithified, gray, micaceous, feldspathic, 

arenaceous silt and sand. Arsenic content of the sediment ranges from <1 to 210 ppm, with the 

highest contents measured in sediment collected at a depth of 320 meters. Samples with high 

arsenic contents typically contain high concentrations of sulfur. The greatest amount of arsenic 

was extracted using the oxidative hydrogen peroxide and hydrochloric acid extraction solution. 

The extraction results are consistent with the apparent association of arsenic in sulfur in the bulk 

chemical analyses. Pyrite is typically the most abundant form of sulfur in the sediment and is 

dissolved by the oxidative extraction. 

Introduction 

The ingestion of arsenic-rich ground water was first proposed in 1983 as the cause for a 

range of health problems experienced by residents of the Bengal basin (Gorair and others, 1984; 

Saha, 1984; 1995). Subsequent testing of wells in the basin has determined that ground water 

across the basin locally contains high concentrations of arsenic. An estimated 40 million residents 

(20% of the population of Bangladesh) currently consume water that exceeds local drinking water 

standards of 50 μg/L arsenic (World Bank, 2005). In addition, this contaminated water is used to 

irrigate farms needed to supply food for the resdients. Explanations for the contamination have 

consistently proposed that naturally occurring arsenic is released from ferric oxyhydroxide grain 

1
coatings in response to microbially facilitated reduction in the subsurface (Nickson and others, 

2000; Kinniburgh, and Smedley, 2001; Harvey and others, 2002; Horneman and others, 2004; 

Ravenscroft and others, 2004). This report presents the results of characterization of sediment 

samples collected in the area of Srirampur village in southeastern Bangladesh (fig. 1). 

Interpretation of these results will be presented in manuscripts currently in preparation. Funding 

for this work was provided by the U.S. Agency for International Development and the World Bank. 

A primary concern for aid agencies seeking to alleviate the health crisis caused by the 

consumption of arsenic-rich water is to identify methods or sources that will supply safe drinking 

water. One of the mitigation strategies proposed is to install water wells to depths below 150 m. 

Water analyses summarized by the National Arsenic Mitigation Information Center (NAMIC) and 

other databases (www.bamwsp.org) show that the frequency of wells that produce water exceeding 

the drinking water standard decrease with increasing depth. A small fraction of existing wells 

deeper than 150 m produce water that exceeds the 50 μg/L drinking water standard 

(www.bamwsp.org). Although the lack of arsenic in water produced by these deeper wells has been 

attributed to removal of arsenic in the sediment by ground water flow, no evidence has been offered 

to verify the loss of arsenic. This investigation determined the composition of sediment from 

depths as great as 400 meters to provide the data necessary to evaluate the viability of deeper 

aquifers to sustain production of water with low arsenic contents. 

Setting 

Srirampur village is located approximately 45 kilometers southeast of the capital city of 

Dhaka in Kachua upazila, Chandphur District (fig. 1). Testing of 17,400 tubewells in the Kachua 

upazila determined that 98% produce water containing more than 50 μg/L of arsenic 

(www.bamwsp.org). Srirampur is 18 km east of the Meghna Estuary, which is currently the 

principal discharge for the Ganges, Brahmaputra, and Meghna River drainage basins. The study 

area is located physiographically on the Tippera surface (Morgan and McIntire, 1959) within and 

adjacent to the Meghna river floodplain. Much of the sediment transported by the rivers and 

deposited in the basin originates in crystalline rocks of the high Himalayas, with lesser additions 

from the Indian Shield to the west, the Shillong Plateau to the north, and Tertiary-age sedimentary 

rock that are exposed in the Indo-Burman Range to the east. The Tertiary rock is composed mostly 

of sediment originally shed from the ancestral Indian Shield and early Himalaya uplift, which was 

buried along the paleo-Indian continental margin, lithified, and tectonically uplifted into the 

weathering zone during the India-Asia collision. Holocene sediment accumulation rates for the 

Bengal delta range up to 1 cm year-1 as a result of the large amount of sediment transport, sea level 

rise, and accommodation space created by subduction (Goodbred and Kuehl, 2000). 

Methods 

Sample Collection 

Sediment samples were collected in the spring and summer of 2003 from two boreholes by 

coring selected depth intervals. The borehole drilled by the Geological Survey of Bangladesh 

(GSB), SH-1, was located at 23.33933° N latitude and 90.92603° E longitude and was drilled to a 

total depth of 405 meters. Drilling fluid used by GSB was a mix of water and bentonite with the 

addition of barite when drilling advanced below 260 m depth. The upper 125 m of sediment 

collected during drilling of a well by the Bangladesh Water Development Board (BWDB), BWDB2
1, was also sampled. BWDB-1 is located at 23.33933° N and 90.92253° E, approximately 370 m 

west of SH-1. Forty-three samples were collected from SH-1, and 14 from BWDB-1. Samples 

were described in the field (appendix 1). Bulk samples were air-dried prior to analysis and are 

designated as –AD in the appendices. 

Aliquots of 42 sediment samples recovered from the SH-1 borehole were placed in glass 

vials filled with argon gas at the drill site to preserve the oxidation state of iron and arsenic in the 

sample. These preserved samples are identified as –P in subsequent tables. Some preserved 

samples were collected at different depth intervals than the –AD samples, as listed in appendix 2. 

Preserved samples were collected using a detipped 10 mL syringe that was used to extract sediment 

in the lowest section of the core barrel (immediately above the coring bit). This material was 

considered to be the least contaminated by drilling fluid. The sediment collected in the detipped 

syringe was then transferred to an amber glass vial equipped with a Teflon coated septum. 

Sediment was transferred into the vial while the vial was purged with flowing argon gas. The vial 

was then capped, and purged for an additional five minutes by using needles to pass argon through 

the septum. After purging, the vial was frozen until shipment to the United States for analysis. 

During shipment the vials thawed but were promptly refrozen upon arrival at the USGS 

laboratories. 

Figure 1. Map of Bangladesh showing the location of the Srirampur study site. Srirampur is located 

approximately 50 kilometers west of the border with India, 80 kilometers north of the Bay of Bengal 

and 18 kilometers east of the Meghna estuary. 

3
Grain-size Analysis 

Aliquots of 43 bulk sediment samples were analyzed to determine grain-size using a 

Malvern Mastersizer S long bed laser refraction instrument. Approximately 0.3 gram splits of 

sediment were soaked overnight in 40 mL of distilled water amended with 20 mL of 0.25 weight 

percent sodium hexametaphosphate to enhance particle dispersion. The disaggregation treatments 

were intended to separate individual mineral particles. Consistent with the observed lack of 

cementation, Srirampur sediment samples dispersed easily. Grain-size characteristics of the 

samples are presented in appendix 3. 

Mineralogy 

To determine the mineral composition, splits of 57 bulk samples were ground to < 50 μm in 

an agate shatterbox prior to analysis by X-ray diffraction. Side-packed mounts were prepared by 

loading the powdered sample against frosted glass to minimize preferential orientation. The 

mounts were analyzed using Ni-filtered, Cu Kα radiation on a Siemens D500 equipped with a 

graphite monochromater. Samples were scanned from 4 to 64 degrees 2θ with a 0.02 degree step 

size and count time of 2 seconds per step. 

Seven samples were prepared according to the methods described in Eberl (2002) for 

quantitative mineral analysis. This method requires micronizing the sample with ZnO as an 

internal standard. The ROCKJOCK (Eberl, 2002) program was then used to calculate the 

abundance of major mineral constituents. Analytical precision of the ROCK JOCK method is 

estimated to be within ten relative percent. Results of the qualitative and quantitative XRD 

analyses are listed in appendices 4 and 5. 

Bulk Chemical Analyses 

Fifty-seven air-dried samples were analyzed to determine chemical composition by 

Combustion, Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), Energy 

Dispersive X-ray Fluorescence (EDXRF), and Hydride Generation Atomic Absorption 

Spectrophotometery (HGAAS). All samples were homogenized in a mortar and pestle, split, and 

ground in an agate shatterbox prior to analysis. The combustion procedure of Brown and Curry 

(2002a, 2002b) determined the total carbon and sulfur concentrations. Carbonate carbon was 

measured by evolution of carbon dioxide using the Chittick method (Dreimanis, 1962). Samples 

analyzed by ICP-AES were first dissolved using the four acid digestion as described in Briggs 

(2002). ICP-AES determined the concentration of 40 elements. EDXRF analyses followed the 

procedure of Siems (2002), in which a pressed powder pellets were analyzed directly for 30 

elements. Arsenic concentrations were also obtained using HGAAS according to the method of 

Hageman and others (2002). HGAAS was used because of its lower detection limit, and higher 

precision and accuracy. Detection limits, accuracy, and precision of all methods were consistent 

with those described in references listed above. Results of the chemical analyses of the bulk 

samples are listed in appendices 6 though 9. 

Extraction Chemical Analyses 

Selected sediment samples were treated with chemical reagents to extract constituents of the 

sediment. Extractions were conducted to evaluate the exchangeable cations, the solid phase 

residence of iron and arsenic, and the speciation of sulfur. A strontium chloride (SrCl2) solution 

was used to determine the abundance of soluble and exchangeable cations. Acid, reducible, and 

4
oxidizable extractions were applied sequentially to evaluate the distribution of arsenic among the 

solid phases. Acid-volatile sulfide (AVS), acid-soluble sulfate, and disulfide (DI) were extracted 

from only selected samples. 

Exchangeable major ions were extracted by transferring 5 to 10 gram aliquots of sixteen 

preserved sediment samples into an acid-washed, amber serum vial containing 40 mL of a 0.1 M 

solution of SrCl2. The vial and SrCl2 solution were flushed with flowing, high-purity nitrogen prior 

to and during addition of the sediment. Nitrogen continued to purge the vial for 5 minutes 

following addition of the sediment. The vial was sealed with a rubber septum and wrapped with 

aluminum foil to exclude light. All wrapped vials were agitated on a wrist shaker for one hour to 

disaggregate and disperse the sediment. The vials were then shaken by hand intermittently during 

the 24 hour reaction period. After reaction, 30 mL of solution was withdrawn from the serum vial 

using a syringe. The solution was then filtered through a 0.2 μm filter and acidified with highpurity nitric acid to a pH <2. Acidified solutions were analyzed by ICP-AES for calcium, 

magnesium, potassium, and sodium and spectrophotometrically for total iron using the 

Orthophenanthroline method of Clescri and others (1998). Results of the analyses are presented in 

appendix 10. Duplicate extractions with strontium chloride solution were reproduced within 20 

relative percent for all measured constituents. The variability was attributed to visible grain-size 

heterogeneity within the frozen samples. Although variable in absolute concentration, the relative 

abundance of exchangeable cations within each sample was within 5 relative percent for all ions. 

Chemical extractions applied to estimate the solid-phase residence of arsenic were selected 

to dissolve phases detected in the sediment samples. The acid (0.5N HCl) and reducible extractions 

(trivalent titanium chloride (TiCl3) and ethylenediaminetetraacetic acid (EDTA)) were based on 

methods described by Heron and Christensen (1995). Treatment of sediment with 0.5N HCl was 

expected to dissolve carbonate minerals (calcite, dolomite, rhodocrosite, and siderite), vivianite, 

and amorphous FeS phases. The Ti(III)-EDTA reagent was selected for its ability to dissolve 

goethite and hematite with minimal impact of silicate minerals (Ryan and Gschwend, 1991). 

Hydrogen peroxide (H2O2) in a solution of HCl provided the oxidative extraction intended to 

dissolve arsenic bound to more refractory sulfide minerals (pyrite) and organic matter. 

A 3 to 5 gram aliquot of each of 42 frozen, preserved sediment samples was transferred to 

an acid-washed amber serum vial under flowing high-purity nitrogen. The sediment was exposed 

to air for a few minutes during the transfer but experiments determined that a minimum of 30 

minutes of exposure of the cold sediment was needed before iron oxidation was detectable in the 

0.5 N HCl extract solutions. Forty mL of 0.5 N hydrochloric acid was added; the vial was sealed 

with a rubber septum and purged with nitrogen gas, wrapped with aluminum foil, and shaken 

periodically. Following 24 hours, 30 mL of the acid solution was withdrawn through the septum 

and filtered through a 0.2 μm syringe filter. An aliquot of the solution was immediately analyzed 

to determine the concentration of dissolved ferrous iron and dissolved total iron using the 

Orthophenanthroline method (Clesceri and others, 1998). A second aliquot of the remaining 

solution was analyzed by ICP-AES for 25 elements and for arsenic by HGAAS. The 0.5 N HCl 

extraction also was applied to 33 of the air-dried samples. The extracts from the acid solutions 

were only analyzed to measure the oxidation state of dissolved iron to estimate the magnitude of 

change to the iron redox state caused by exposing the samples to air. Results of the analyses of 

both sets of 0.5N HCl extractions are presented in appendices 11 through 13. Measured 

concentrations of extractions with 0.5 N HCl of replicate samples of the sediment typically 

reproduced within 15 percent, but ratios of ferrous to total extractable iron were reproduced within 

3 percent. Variations in element concentrations in the replicates are attributed to sample 

heterogeneity. 

5
The sediment remaining after the 0.5N HCl extraction of the preserved sediment was 

filtered, rinsed thoroughly with distilled water, and air-dried at 50 oC prior to reaction with the 

reducing solution. Because the most reactive constituents of the sample were removed by 0.5 N 

HCl, drying was determined to have a minimal effect on the redox condition of the remaining 

solids. Approximately 2 to 3 grams of the dried solid was mechanically split from the residue and 

combined with 40 mL of 0.008 molar TiCl3 in 0.05 molar EDTA with a pH adjusted to 6 using 

sodium hydroxide. The reducing solution was prepared under flowing nitrogen. The serum vial 

was sealed, purged with nitrogen for 5 additional minutes, wrapped with foil to exclude light, and 

shaken intermittently over the reaction period. Following 24 hours of reaction, 30 mL of solution 

was removed using a syringe. The solution was then filtered through a 0.2 μm syringe filter. The 

Ti(III)-EDTA solution has a distinct magenta color prior to reaction. This color was maintained, 

although it was less intense, at the completion of the reaction time indicating that the Ti(III)was not 

consumed. The filtered solutions were analyzed for iron, aluminum, magnesium, and manganese 

using standard methods of atomic absorption spectrophotometry. Hydride generation atomic 

fluorescence spectrometry was used to determine the concentration of dissolved arsenic. Results of 

the analyses of the Ti(III)-EDTA extract solutions are presented in appendix 14. Duplicate 

analyses of the sediment with Ti(III)-EDTA were typically within 4 percent. 

Approximately 0.5 grams of the air-dried residue remaining for each sample after the 

Ti(III)-EDTA extraction was combined with 5 mL of 2.4 molar HCl and 10 percent H2O2

. The 

solution and sediment reacted for 2 hours, and then 3 mL of 20% H2O2 was added. Following two 

additional hours of reaction, the resulting mixtures were slowly heated to 40 °C in a water bath for 

approximately 14 hours. The resulting solutions were then filtered though a 0.45 μm filter and 

diluted to a total volume of 25 mL. The method was intended to dissolve sulfide minerals in the 

sediment and was tested using coarse-grained hydrothermal pyrite. Approximately 95% of the 

hydrothermal pyrite dissolved during this procedure. Hydride generation atomic fluorescence 

spectrometry was used to measure the arsenic content of the solutions as presented in appendix 15. 

Duplicate sediment analyses with the H2O2-HCl extraction were consistently within 10 percent. 

The abundances of AVS, acid-soluble sulfate, and DI were determined following the 

extraction scheme of Tuttle and others (1986). Sulfur speciation was determined on a 2 to 5 gram 

aliquot of preserved sediment that was transferred while only partially thawed into the reaction 

vessel. Under flowing nitrogen the sample was combined with 80 milliliters of 6 N HCl that 

contained 2 grams of stannous chloride (SnCl2). The SnCl2 was added to reduce ferric iron in the 

samples that might oxidize evolved hydrogen sulfide (H2

S) (Rice and others, 1993). After 15 to 30 

minutes, the reaction vessel was heated to boiling to increase the reaction rate. The evolved H2S 

was carried in flowing nitrogen through a reservoir of pH 4 buffer to remove HCl and bubbled 

through a trap containing 1 N silver nitrate (AgNO3) until the reaction was complete. The resulting 

silver sulfide (Ag2

S) was collected by filtration, air-dried, and weighed to measure the abundance 

of AVS. The acid solution was separated from the residual solid by filtration, and the residual solid 

was air-dried and weighed. The solution was reacted with 10 mL of 10% barium chlorite to 

precipitate dissolved sulfate as barium sulfate, which is considered acid-soluble sulfate. The 

residual sediment from the AVS extraction was placed in a reaction vessel under flowing nitrogen 

and combined with 50 mL of 1M chromous chloride (CrCl2) in 4 N HCl containing 10 milliliters of 

ethanol. Chromium (II) converts reducible sulfide minerals (i.e., pyrite) to H2S. The H2S is carried 

to a 1N AgNO3 trap as described for the AVS extraction and precipitated as Ag2S. The CrCl2

solution is boiled for approximately 1 hour or until evolution of H2S has stopped. Results of the 

sulfur speciation are listed in appendix 16. 

6
Results 

Physical and mineralogical characteristics. 

Sediment samples from the Srirampur boreholes are typically gray and micaceous ranging 

from silt to sand. Samples collected at depths of 46 to 48 meters are distinctly brown relative to 

other samples and may be Pleistocene sediment near the Holocene-Pleistocene unconformity 

(Goodbred and Kuehl, 2000). The relative grain size distribution of the sample materials from the 

GSB bore-hole are plotted in figure 2. XRD analyses identified quartz, plagioclase, and potassium 

feldspar as the major constituents of the sediment, with minor amounts of chlorite, muscovite, 

biotite and amphibole (appendices 4 and 5). Confirmed authigenic phases detected by XRD in 

some samples include siderite and pyrite; calcite was not detected. 

Figure 2. Ternary diagram of results of grain size analyses (appendix 3) in sediment samples 

recovered from the GSB borehole in Srirampur, Kachua. 

Bulk Chemical Composition 

The median, minimum, and maximum concentration of chemical constituents measured in 

bulk air-dried sediments from the two bore holes are listed in table 1. Precision of duplicate splits 

of the same sample were within 10 relative percent for elements with concentrations greater than 3 

times the detection limit for combustion, Chittick, ICP-AES, and EDXRF methods. Elements 

present in lower concentrations were reproduced within 30 relative percent. Duplicate total arsenic 

measurements by HGAAS were consistently within 4 relative percent. Analyses of solid and rock 

standards submitted with the samples yielded results within the precision and accuracy described in 

Taggert (2002). 

7
Total arsenic concentrations of the sediment range from 0.6 to 210 ppm as measured by 

HGAAS. The highest concentrations occur between 307 and 310 meters depth. Samples within 

this depth interval are also distinguished by high concentrations of sulfur. Concentrations of other 

elements in the high arsenic interval were similar to other samples from the boreholes. 

Unusually high concentrations of barium (>400 ppm) were detected in sediment collected 

from the GSB borehole below depths of approximately 240 meters. The drilling engineer reported 

that 240 m was the depth at which barite was added to the drilling fluid. A scanning electron 

microscope (SEM) examination of sediment below 240 m revealed the presence of uniform, small 

prisms of barite (BaSO4) identical to those added to the drilling fluid. Because sulfur is an 

important component of the processes active within the sediment, we subtracted the contaminant 

barite from the bulk sulfur analyses using the following procedure. 

Potassium and barium have a recognized geochemical association in potassium feldspars 

and micas (Puchelt, 1978). This association is evident in the sediment collected at Srirampur. 

Samples recovered from depths less than 230 meters (uncontaminated with barite) have a strong 

correlation of barium and potassium (r2 = 0.9). The amount of excess barium in the deeper samples 

was then calculated based on the amount of barium expected for the measured amount of potassium 

(equation 1). Because of the uncertainty in the analytical data and the expected variance from an 

ideal correspondence between Ba and K, only samples with greater than 200 ppm excess barium 

were considered to have sufficient contamination to merit correction. In addition, barium contents 

of 200 ppm, if contained in barite, would correspond to approximately 0.005 weight percent sulfur, 

which is close to the detection limit of the sulfur analyses. Accordingly, sulfur concentrations in 

the samples were corrected by using equation 2. Results of the recalculation of sulfur concentration 

are plotted in figure 3. Note that the very high sulfur concentrations in some samples are 

unaffected by the barite correction. 

Ba (ppm) excess = Ba (ppm) measured – (174* K (wt. %) + 76) (1) 

Sulfur (ppm) corrected = Sulfur (ppm) measured – (0.233 * Ba (ppm) excess) (2) 

8
Figure 3. Comparison of the sulfur concentration measured in the sediment with concentrations 

corrected for barite contamination of the samples. Significant differences between measured and 

corrected sulfur contents are apparent in mot samples deeper than 240 meters. 

9
Table 1. Median, minimum, and maximum concentrations of chemical constituents of sediment 

recovered from the two boreholes in Srirampur, Kachua, Bangladesh. 

[ICP-AES, Inductively Coupled Plasma Atomic Emission Spectroscopy; EDXRF, Energy Dispersive X-ray 

Fluorescence Spectrometry; HGAAS, Hydride Generation Atomic Absorption Spectrophotometery; *, sulfur 

concentrations listed as corrected values as described in the text; detection ratio is the number of analyses above the 

detection limit/total number of analyses] 

Element 

(units) 

Analytical 

Method 

Median Minimum Maximum Detection 

Ratio 

Al (wt.%) ICP-AES 4.8 2.7 9.8 57/57 

Ca (wt.%) ICP-AES 0.68 0.26 1.4 57/57

Fe (wt.%) ICP-AES 2.2 0.87 7.4 57/57

K (wt.%) ICP-AES 1.7 1.2 2.9 57/57

Mg (wt.%) ICP-AES 0.39 0.16 1.9 57/57

Na (wt.%) ICP-AES 1.0 0.52 1.4 57/57

P (wt.%) ICP-AES 0.03 0.007 0.074 57/57

Ti (wt.%) ICP-AES 0.22 0.093 0.55 57/57

C-total (wt.%) Combustion 0.19 0.05 1.5 55/57

C-carbonate 

(wt.%) 

Chittick 0.07 0.05 0.33 43/43 

S (wt.%)* Combustion 0.027 <0.005 1.47 57/57 

Ag (ppm) ICP-AES <2 <2 <2 0/57 

Ag (ppm) EDXRF <1 <1 <1 0/57 

As (ppm) ICP-AES <10 <10 230 8/57 

As (ppm) EDXRF 3 <2 190 35/57 

As (ppm) HG-AAS 2.7 0.6 210 57/57 

Au (ppm) ICP-AES <8 <8 <8 0/57 

Ba (ppm) ICP-AES 420 270 1700 57/57 

Ba (ppm) EDXRF 420 290 1700 57/57 

Be (ppm) ICP-AES 1.8 <1 3.4 57/57 

Bi (ppm) ICP-AES <10 <10 <10 0/57 

Bi (ppm) EDXRF <5 <5 <5 0/57 

Br (ppm) EDXRF <1 <1 3 5/57 

Cd (ppm) ICP-AES <2 <2 2.9 1/57 

Cd (ppm) EDXRF <1 <1 3 2/57 

Ce (ppm) ICP-AES 58 29 110 57/57 

Ce (ppm) EDXRF 68 40 120 57/57 

Co (ppm) ICP-AES 7.2 1.4 120 57/57 

Cr (ppm) ICP-AES 32 19 130 57/57 

Cr (ppm) EDXRF 40 23 140 57/57 

Cs (ppm) EDXRF 6 <5 18 48/57 

Cu (ppm) ICP-AES 5.2 1.4 190 57/57 

Cu (ppm) EDXRF 9 3 190 57/57 

Eu (ppm) ICP-AES <2 <2 <2 0/57 

Ga (ppm) ICP-AES 10 4.3 24 55/57 

Ga (ppm) EDXRF 11 5 24 57/57 

Ge (ppm) EDXRF <2 <2 2 1/56 

Ho (ppm) ICP-AES <4 <4 <4 0/57 

La (ppm) ICP-AES 30 14 56 57/57 

La (ppm) EDXRF 37 20 67 57/57 

10
Table 1. Median, minimum and maximum of chemical constituents—Continued. 

Element 

(units) 

Analytical 

Method 

Median Minimum Maximum Detection 

Ratio 

Li (ppm) ICP-AES 14 8.2 83 57/57 

Mn (ppm) ICP-AES 570 82 2700 57/57 

Mo (ppm) ICP-AES <2 <2 4.8 19/57 

Mo (ppm) EDXRF <2 <2 4 3/57 

Nb (ppm) ICP-AES 9.4 2 23 57/57 

Nb (ppm) EDXRF 9 4 18 57/57 

Nd (ppm) ICP-AES 25 12 43 57/57 

Nd (ppm) EDXRF 33 16 59 57/57 

Ni (ppm) ICP-AES 13 8 84 57/57 

Ni (ppm) EDXRF 16 9 87 57/57 

Pb (ppm) ICP-AES 17 12 38 57/57 

Pb (ppm) EDXRF 18 12 33 57/57 

Rb (ppm) EDXRF 87 58 240 57/57 

Sb (ppm) EDXRF <2 <2 <2 0/57 

Sc (ppm) ICP-AES 7 3.5 19 57/57 

Se (ppm) EDXRF <1 <1 <1 0/57 

Sn (ppm) ICP-AES <5 <5 19 15/57 

Sn (ppm) EDXRF 3 <2 6 42/57 

Sr (ppm) ICP-AES 120 67 170 57/57 

Sr (ppm) EDXRF 130 69 160 57/57 

Ta (ppm) ICP-AES <20 <20 <40 0/57 

Th (ppm) ICP-AES 12.5 4 24 56/57 

Th (ppm) EDXRF 11 4 21 55/57 

U (ppm) ICP-AES <100 <100 <100 0/57 

U (ppm) EDXRF <4 <4 6 15/57 

V (ppm) ICP-AES 44 25 140 57/57 

V (ppm) EDXRF 46 27 140 57/57 

W (ppm) EDXRF <5 <5 40 1/57 

Y (ppm) ICP-AES 16 6 31 57/57 

Y (ppm) EDXRF 22 10 39 57/57 

Yb (ppm) ICP-AES 1.6 <1 3.6 54/57 

Zn (ppm) ICP-AES 35 17 150 57/57 

Zn (ppm) EDXRF 41 20 140 57/57 

Zr (ppm) EDXRF 180 78 360 57/57 

Chemical Extractions 

The strontium chloride extraction determined that calcium, magnesium, and sodium are the 

dominant exchangeable cations, with smaller abundances of potassium (appendix 10). 

Exchangeable iron is relatively abundant in the shallowest sediment samples (< 80 m depth), 

decreases to low concentrations between 80 and 180 m, and is generally below detection in samples 

deeper than 180 m. Considered on the basis of equivalents: sodium ranges from 17 to 60 percent, 

calcium; 16 to 40 percent, magnesium; 11 to 44 percent; potassium 1 to 9 percent; and iron less 

than 6 percent of the measured exchangeable ions. The relative abundance of exchangeable cations 

other than iron does not vary systematically with depth. 

Analyses of the 0.5N HCl extraction solutions verified that the sediment is chemically 

reduced with respect to iron. Greater concentrations of iron were extracted by the acid treatment 

than any other measured constituent (0.12 to 6.6 wt.%; appendix 13). Together with Fe2+/Fetotal 

values that are typically greater than 0.9, the amounts of extracted iron are attributed primarily to 

11
dissolution of siderite. The lowest Fe2+/Fetotal value (0.62) was measured on the sediment collected 

at 46.5 m, which is the brown sand tentatively identified as sediment oxidized during the HolocenePleistocene unconformity. As expected, iron dissolved from the air-dried sediment using 0.5 N 

HCl typically contained lower Fe2+/Fetotal values than the preserved samples. 

Substantial amounts of aluminum, calcium, magnesium, manganese, potassium, sodium, 

and silicon were also dissolved by 0.5 N HCl. These elements are attributed to dissolution of 

detrital silicates and siderite. Reaction of the acid with portions of feldspars, micas, and other 

detritus weathered during transport and shallow burial likely accounts for Al, Si, K, Na, and some 

of the Ca, Mg, and Mn. Dissolution of siderite likely released substantial amounts Ca, Mg, and Mn 

as well as iron based on preliminary electron microbeam analyses of siderite grains. 

Wilkin and Ford (2002) noted a decrease in the amount of dissolved arsenic when sulfidic 

sediment treated with HCl solutions. This challenges the ability of HCl extracts to reliably estimate 

the abundance of labile arsenic. Wilkin and Ford (2002) attributed the arsenic loss to precipitation 

of amorphous orpiment (As2S3) by reaction of dissolved arsenic and H2S evolved by reaction of the 

AVS with HCl. Therefore, the arsenic concentrations of the 0.5N HCl extract solutions in this 

study should be viewed with caution. The potential of orpiment precipitation in the 0.5N HCl 

extraction was evaluated using Geochemist’s Workbench with the LLNL V8 R6 combined 

database that was modified with the thermodynamic data of Nordstrom and Archer (2003) and 

Pokrovski and others (2002). Results of AVS extraction (appendix 16) and the abundance of 

arsenic and iron in the 0.5N HCl solutions (appendices 12 and 13) were used to evaluate the degree 

of saturation of amorphous orpiment. The amount of AVS extracted by the 0.5N HCl is likely to be 

smaller than the AVS extracted by hot 6N HCl, so the calculations are considered to indicate the 

maximum saturation values. Five of the 16 samples were oversaturated with respect to amorphous 

orpiment although the maximum saturation index (saturation index = log(ion activity product / 

equilibrium constant)) was 2. Because the samples selected for sulfur speciation generally contain 

greater contents of sulfur than most of the sediment samples, the number of samples oversaturated 

with amorphous orpiment is likely to be proportionally smaller. Similar equilibrium calculations 

with the closed-system results of Wilkin and Ford (2002) determined that more than 80% of 

dissolved arsenic remained in solution when amorphous orpiment SI values were <2. Less than 

20% of the arsenic remained in solution when solution compositions exceeded SI values >4. This 

comparison does not eliminate the concern for orpiment precipitation in the Srirampur sediment, 

but the problem is likely to be less significant than in the sediment evaluated by Wilkin and Ford 

(2002). 

Approximately a tenth of the amount of iron, manganese, aluminum, and arsenic extracted 

by 0.5 N HCl were dissolved by the Ti(III)-EDTA extraction (appendix 14). The amount of iron 

dissolved was the largest of the four measured constituents. Greater amounts of iron and arsenic 

extracted by this reducing treatment were measured on shallow sediment (<80 m) than from the 

deeper samples. Aluminum was typically dissolved in greater amounts from samples with smaller 

grain size; this is attributed to greater abundance of micas and clays in those samples. 

Only arsenic concentration was determined in the solutions produced by the oxidative 

extraction (H2O2-HCl) (appendix 15). The amount of arsenic extracted by this treatment, 0.3 to 6 

ppm, was consistently greater than the contents extracted by the 0.5N HCl or Ti(III)-EDTA 

(appendices 13, 14). 

Sulfur speciation extractions detected AVS, acid-soluble sulfate, and reducible sulfur in the 

borehole sediment (appendix 16). Concentrations of AVS ranged from 10 to 280 ppm, acid-soluble 

sulfate measured <10 to 110 ppm, and reducible sulfur was typically the most abundant form, 20 to 

1170 ppm. Reducible sulfide is attributed to pyrite, which is consistent with detection of pyrite by 

XRD and optical microscopy. The acid-soluble sulfate extracted from the deeper samples may 

12
reflect a contribution from the drilling fluids, and this will be tested with future sulfur isotope 

analyses. For several samples the total amount of sulfur extracted is substantially different than the 

total sulfur concentrations measured for the bulk, air-dried sediment (appendix 6). The speciation 

scheme was evaluated with synthetic standards and determined to be reliable; therefore, the 

contrasting values between the air-dried and preserved samples are attributed to sample 

heterogeneity. 

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Netherlands, Kluwer Academic Publishers, p. 1-26. 

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Arsenic in groundwater of the Bengal basin, Bangladesh: Distribution, field relations and 

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14
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15
Appendix 1. Depth and description of air-dried sediment samples from the BWDB (TH/S) and GSB 

(SH-1/ ) boreholes, Srirampur, Kachua. 

Sample Depth Description 

(meters) 

TH/S 20-AD 6.1 – 6.7 dark gray clayey silt 

TH/S 60-AD 18.3 – 18.9 light gray-green fine to medium sand 

TH/S 110-AD 33.5 – 34.1 gray-green fine to medium sand 

TH/S 120-AD 36.6 – 37.2 dark gray-green clayey fine sand 

TH/S 140-AD 42.7 – 43.3 gray-green fine to medium sand 

TH/S 160-AD 48.8 – 49.4 brown clayey silt 

TH/S 170-AD 51.8 – 52.4 light gray-green medium sand 

TH/S 180-AD 54.9 – 55.5 gray-green fine to medium sand 

TH/S 210-AD 64.0 – 64.6 light gray-green medium sand 

TH/S 230-AD 70.1 – 70.7 gray-green medium sand 

TH/S 320-AD 97.5 – 98.1 light gray-green medium sand 

TH/S 360-AD 109.7 – 110.3 light gray-green medium sand 

TH/S 380-AD 115.8 – 116.4 light gray-green medium sand 

TH/S 400-AD 121.9 – 122.5 light gray-green medium sand 

SH-1/1-AD 21.3 – 22.6 gray-green clayey fine sand 

SH-1/2-AD 22.6 – 23.3 gray-green fine sand 

SH-1/3-AD 27.4 – 28.2 gray-green very fine sandy clay 

SH-1/4-AD 45.7 – 46.9 light brown clayey medium to fine sand 

SH-1/5-AD 58.7 – 59.8 gray-green clayey silt 

SH-1/6-AD 73.7 – 73.9 gray-green medium sand 

SH-1/7-AD 74.1 light gray-green clayey fine sand 

SH-1/8-AD 82.9 – 83.8 dark gray-green very fine sandy clay 

SH-1/9-AD 93.3 – 94.2 gray-green clayey medium sand 

SH-1/10-AD 113.7 – 114.6 gray-green clayey fine to medium sand 

SH-1/11-AD 123.8 – 124.4 light gray-green pebbly clayey medium sand 

SH-1/12-AD 137.2 – 138.0 dark gray very fine clayey sand 

SH-1/13-AD 157.9 – 158.5 gray-green silty fine sand 

SH-1/14-AD 167.4 – 167.7 gray-green very fine sandy silt 

SH-1/15-AD 175.9 – 176.1 light gray-green medium sand 

SH-1/16-AD 182.5 – 182.8 light gray-green medium sand 

SH-1/17-AD 182.8 – 182.9 mottled gray and light gray-green silty clay, partially lithified? 

SH-1/18-AD 189.5 – 190.4 light gray-green medium sand 

SH-1/19-AD 196.3 – 197.3 light gray-green medium to coarse sand 

SH-1/20-AD 207.8 – 208.2 light gray-green medium sand 

SH-1/21-AD 214.3 – 215.6 light gray-green medium sand 

SH-1/22-AD 221.7 – 222.6 light gray-green medium sand 

SH-1/23-AD 228.7 light gray-green medium sand 

SH-1/24-AD 236.3 – 237.2 light gray-green medium sand 

16
Appendix 1. Depth and description of air-dried sediment samples—Continued 

Sample Depth Description 

(meters) 

SH-1/25-AD 245.1 – 146.3 light gray-green medium to coarse sand 

SH-1/26-AD 253.7 – 254.6 light gray-green clayey fine to medium sand 

SH-1/27-AD 260.1 – 261.3 light gray-green fine sand 

SH-1/28a-AD 267.4 – 268.6 light gray-green medium sand 

SH-1/28b-AD 283.2 – 283.8 gray-green clayey fine sand 

SH-1/29-AD 289.9 – 290.9 light gray-green medium sand 

SH-1/30-AD 290.9 light gray-green fine sand 

SH-1/31-AD 299.7 – 300.1 light gray-green fine sand 

SH-1/32-AD 307.3 – 308.2 gray-green very fine sandy clay 

SH-1/33-AD 321.4 – 322.6 gray-green silty clay 

SH-1/34m-AD 326.4 gray-green micaceous medium to coarse sand 

SH-1/34b-AD 325.8 – 326.4 dark gray-green micaceous silty fine sand 

SH-1/35-AD 335.9 – 336.8 gray-green fine to medium sand 

SH-1/36-AD 353.9 – 354.6 gray-green medium sand 

SH-1/37-AD 354.8 – 355.7 gray-green medium sand 

SH-1/38-AD 365.7 – 366.4 gray green medium sand 

SH-1/39a-AD 375.80 – 376.7 dark gray-green silt 

SH-1/39b-AD 375.80 – 376.7 gray silty fine sand 

SH-1/40-AD 387.3 – 388.0 gray-green medium sand 

17
Appendix 2. Depth and description of sediment samples that were preserved in glass vials, flushed 

with argon, and frozen after collection from the GSB borehole, Srirampur, Kachua. 

Sample Depth Description 

(meters) 

SH-1/1-P 22.6 gray-green clayey fine sand 

SH-1/2- P 23.3 gray-green fine sand 

SH-1/3- P 27.4 gray-green very fine sandy clay 

SH-1/4- P 39.3 gray-green clayey fine sand 

SH-1/5- P 46.5 light brown clayey medium to fine sand 

SH-1/6- P 49.7 gray-green clayey silt 

SH-1/7- P 59.8 gray-green clayey silt 

SH-1/8- P 73.9 gray-green medium sand 

SH-1/9- P 83.8 dark gray-green very fine sandy clay 

SH-1/10-P 93.3 gray-green fine to medium sand 

SH-1/11-P 104.6 gray-green clayey fine sand 

SH-1/12-P 114.5 gray-green clayey fine to medium sand 

SH-1/13-P 124.4 light gray-green clayey medium sand 

SH-1/14-P 137.5 gray-green very fine sandy silt 

SH-1/15-P 146.6 gray-green medium sand 

SH-1/16-P 158.5 gray-green silty fine sand 

SH-1/17-P 168.0 gray-green silty fine sand 

SH-1/18-P 176.1 light gray-green medium sand 

SH-1/19-P 182.8 light gray-green medium to coarse sand 

SH-1/20-P 189.9 light gray-green medium sand 

SH-1/21-P 197.3 light gray-green medium sand 

SH-1/22-P 207.9 light gray-green fine to medium sand 

SH-1/23-P 215.5 light gray-green fine to medium sand 

SH-1/24-P 222.6 light gray-green medium sand 

SH-1/25-P 228.7 light gray-green medium to coarse sand 

SH-1/26-P 237.2 light gray-green fine to medium sand 

SH-1/27-P 245.7 light gray-green medium to coarse sand 

SH-1/28-P 253.8 light gray-green medium to coarse sand 

SH-1/29-P 260.7 light gray-green fine sand 

SH-1/30-P 268.3 light gray-green medium sand 

SH-1/31-P 283.7 light gray-green clayey fine sand 

SH-1/32-P 290.7 gray-green very fine sand 

SH-1/33-P 300.1 gray-green silty fine sand 

SH-1/34-P 307.8 gray-green fine sand 

18
Appendix 2. Depth and description of preserved sediment samples—Continued

Sample Depth Description 

(meters) 

SH-1/35-P 316.2 gray-brown medium sand 

SH-1/36-P 326.5 gray, micaceous silty sand 

SH-1/37-P 336.6 gray-green fine to medium sand 

SH-1/38-P 354.3 gray green fine to medium sand 

SH-1/39-P 355.6 gray-green medium sand 

SH-1/40-P 366.6 gray-green medium sand 

SH-1/41-P 376.2 gray silty fine sand 

SH-1/42-P 388.0 gray silty medium sand 

19
Appendix 3. Results of grain size analysis of air-dried sediment samples collected from the GSB 

borehole, Srirampur, Kachua. Designations as sand, silt, and clay follow the size definitions of 

Wentworth (1922). 

[Eric Fisher, Analyst; nd, not determined] 

Sample Sand Silt Clay Description 

(wt.%) (wt.%) (wt.%) 

SH-1/1-AD 48.4 41.8 9.8 silty sand 

SH-1/2-AD 50.8 44.2 5.0 silty sand 

SH-1/3-AD 34.2 56.8 9.0 sandy silt 

SH-1/4-AD 77.7 18.2 4.1 sand 

SH-1/5-AD 0.3 59.0 40.7 clayey silt 

SH-1/6-AD 83.8 13.5 2.7 sand 

SH-1/7-AD 71.1 22.6 6.3 silty sand 

SH-1/8-AD 24.3 64.0 11.7 sandy silt 

SH-1/9-AD 55.1 31.4 13.5 silty sand 

SH-1/10-AD 79.0 14.2 6.7 sand 

SH-1/11-AD 68.6 23.6 7.9 silty sand 

SH-1/12-AD 54.4 36.6 9.0 silty sand 

SH-1/13-AD 80.8 16.7 2.5 sand 

SH-1/14-AD 42.1 51.6 6.2 sandy silt 

SH-1/15-AD 86.4 11.7 1.9 sand 

SH-1/16-AD 83.3 14.5 2.2 sand 

SH-1/17-AD 49.5 43.0 7.5 silty sand 

SH-1/18-AD 96.9 2.4 0.7 sand 

SH-1/19-AD 93.9 5.1 1.0 sand 

SH-1/20-AD 75.4 18.5 6.1 silty sand 

SH-1/21-AD 91.0 7.8 1.2 sand 

SH-1/22-AD 96.8 2.9 0.2 sand 

SH-1/23-AD 95.0 4.2 0.8 sand 

SH-1/24-AD 92.4 6.6 1.0 sand 

SH-1/25-AD 93.7 5.3 1.0 sand 

SH-1/26-AD 63.7 28.0 8.3 silty sand 

SH-1/27-AD 95.7 3.4 0.9 sand 

SH-1/28a-AD 94.7 4.6 0.7 sand 

SH-1/28b-AD nd nd nd -- 

SH-1/29-AD 90.1 8.6 1.3 sand 

SH-1/30-AD 94.4 5.1 0.5 sand 

SH-1/31-AD nd nd nd -- 

SH-1/32-AD 40.4 50.7 8.9 sandy silt 

SH-1/33-AD 51.2 35.5 13.3 silty sand 

SH-1/34m-AD nd nd nd micaceous sand 

SH-1/34b-AD 71.4 27.2 1.4 silty sand 

20
Appendix 3. Results of grain size analysis—Continued 

Sample Sand Silt Clay Description 

(wt.%) (wt.%) (wt.%) 

SH-1/35-AD 84.3 14.4 1.3 silty sand 

SH-1/36-AD 78.4 19.5 2.1 silty sand 

SH-1/37-AD 79.5 18.3 2.2 silty sand 

SH-1/38-AD 69.9 27.9 2.2 silty sand 

SH-1/39a-AD nd nd nd -- 

SH-1/39b-AD 81.1 17.2 1.7 silty sand 

SH-1/40-AD 80.9 16.9 2.2 silty sand 

21
Appendix 4. Major minerals detected by X-ray diffraction analysis of air-dried sediment 

samples from the BWDB (TH/S) and GSB (SH-1) boreholes, Srirampur, Kachua. 

 [XX, major constituent; X, minor constituent; <, not detected; Plag., plagioclase; K-spar, potassium feldspar; Amph., 

amphibole] 

Sample Quartz Plag. K-spar Mica Chlorite Amph. Siderite Pyrite 

TH/S 20-AD XX X X X X X X < 

TH/S 60-AD XX X X X X X < <

TH/S 110-AD XX X X X X X < <

TH/S 120-AD XX X X X X X < <

TH/S 140-AD XX X X X X X < <

TH/S 160-AD XX X X X X < X <

TH/S 170-AD XX X X X X X < <

TH/S 180-AD XX X X X < X < <

TH/S 210-AD XX X X X X X < <

TH/S 230-AD XX X X X X X < <

TH/S 320-AD XX X X X X X < <

TH/S 360-AD XX X X X X X < <

TH/S 380-AD XX X X X X X < <

TH/S 400-AD XX X X X X X < <

SH-1/1-AD XX X X X X X < < 

SH-1/2-AD XX X X X X X < < 

SH-1/3-AD XX X < X X X < < 

SH-1/4-AD XX X < < < < < < 

SH-1/5-AD XX X X X X < < < 

SH-1/6-AD XX X X X < < < < 

SH-1/7-AD XX X X X X X X < 

SH-1/8-AD XX X X X X < X < 

SH-1/9-AD XX X X X X X X < 

SH-1/10-AD XX X X X X X X < 

SH-1/11-AD XX X X X X < X < 

SH-1/12-AD XX X X X X X X < 

SH-1/13-AD XX X X X X < X < 

SH-1/14-AD XX X X X X < X < 

SH-1/15-AD XX X X X < < < < 

SH-1/16-AD XX X X X < X X < 

SH-1/17-AD XX X X X X < X < 

SH-1/18-AD XX X X X X < < < 

SH-1/19-AD XX X X X X < X < 

SH-1/20-AD XX X X X < X X < 

SH-1/21-AD XX X X X X X X < 

SH-1/22-AD XX X X X X < X < 

SH-1/23-AD XX X X X < X X < 

SH-1/24-AD XX X X X X X < < 

22
23

Appendix 4. Major minerals present in air-dried sediment samples as determined by X-ray 

diffraction analysis—Continued

Sample Quartz Plag. K-spar Mica Chlorite Amph. Siderite Pyrite 

SH-1/25-AD XX X X X X X X < 

SH-1/26-AD XX X X X X X < < 

SH-1/27-AD XX X X X X X X < 

SH-1/28a-AD XX X X X X X X < 

SH-1/28b-AD XX X X X X X X < 

SH-1/29-AD XX X X X X X X < 

SH-1/30-AD XX X X X X X X < 

SH-1/31-AD XX X X X X X < < 

SH-1/32-AD XX X X X < < X < 

SH-1/33-AD XX X X X < < < < 

SH-1/34m-AD XX X X X X < X X 

SH-1/34b-AD XX X X X X X < X 

SH-1/35-AD XX X X X X X < < 

SH-1/36-AD XX X X X X X X < 

SH-1/37-AD XX X X X X X X < 

SH-1/38-AD XX X X X X X < < 

SH-1/39a-AD XX X X X X X X < 

SH-1/39b-AD XX X X X X X < < 

SH-1/40-AD XX X X X X X X < 
Sample Quartz K-spar Plag. Siderite Smectite Amph. Muscovite Biotite 

(wt.%) (wt.%) (wt.%) (wt.%) (wt.%) (wt.%) (wt.%) (wt.%

SH-1/1-AD 40 10 23 <1 1 3 9 5. 

SH-1/7-AD 63 9 13 1 3 2 3 6 SH-1/13-AD 57 11 13 1 2 <1 5 2 SH-1/18-AD 54 14 20 <1 <1 <1 3 2 SH-1/22-AD 53 15 16 2 2 1.6 2 3 SH-1/30-AD 57 12 20 1 <1 <1 2 <1 SH-1/33-AD 39 8 11 <0.5 10 <1 10 1 

Appendix 5. Results of quantitative mineralogical analysis by X-ray diffraction of air-dried sediment samples from Srirampur, Kachua. Abundances determined using the ROCKJOCK procedure of Eberl (2002). 

24

 [ K-spar, potassium feldspars, Plag., plagioclase; Amph., amphibole] 
Appendix 6. Results of carbon and sulfur analyses of air-dried sediment samples from the BWDB 

(TH/S) and GSB (SH-1) boreholes, Srirampur, Kachua. Sulfur and total carbon determined by 

Combustion. Carbonate carbon determined using the Chittick method. Sulfur was corrected (Sulfur 

(corr)) for barite contamination as described in the text. 

[nd, not determined] 

Sample Sulfur Sulfur (corr) Total Carbon Carbonate Carbon 

(wt.%) (wt.%) (wt.%) (wt.%) 

TH/S 20-AD 0.045 0.045 0.35 nd 

TH/S 60-AD 0.007 0.007 0.06 nd 

TH/S 110-AD 0.010 0.010 0.07 nd 

TH/S 120-AD 0.007 0.007 0.08 nd

TH/S 140-AD 0.016 0.016 0.11 nd

TH/S 160-AD <0.005 <0.005 0.99 nd

TH/S 170-AD 0.012 0.012 0.09 nd

TH/S 180-AD 0.007 0.007 0.03 nd

TH/S 210-AD 0.006 0.006 0.11 nd

TH/S 230-AD 0.010 0.010 0.10 nd

TH/S 320-AD 0.010 0.010 0.05 nd

TH/S 360-AD 0.015 0.015 0.09 nd

TH/S 380-AD 0.005 0.005 0.11 nd

TH/S 400-AD <0.005 <0.005 0.08 nd

SH-1/1-AD 0.045 0.045 0.22 0.06 

SH-1/2-AD 0.024 0.024 0.17 0.09 

SH-1/3-AD 0.049 0.049 0.54 0.14 

SH-1/4-AD 0.015 0.015 0.32 0.27 

SH-1/5-AD 0.005 0.005 0.65 0.08 

SH-1/6-AD 0.005 0.005 0.09 0.05 

SH-1/7-AD 0.024 0.024 0.37 0.12 

SH-1/8-AD 0.110 0.110 0.69 0.17 

SH-1/9-AD 0.031 0.031 0.30 0.08 

SH-1/10-AD 0.051 0.051 0.33 0.09 

SH-1/11-AD 0.049 0.049 0.69 0.32 

SH-1/12-AD 0.044 0.044 0.60 0.18 

SH-1/13-AD 0.058 0.058 0.23 0.09 

SH-1/14-AD 0.130 0.130 0.45 0.14 

SH-1/15-AD 0.008 0.008 0.08 0.04 

SH-1/16-AD 0.005 0.005 0.12 0.04 

SH-1/17-AD 0.007 0.007 0.62 0.06 

SH-1/18-AD 0.021 0.021 0.09 0.03 

SH-1/19-AD 0.045 0.045 0.46 0.08 

SH-1/20-AD 0.041 0.041 0.91 0.30 

SH-1/21-AD 0.029 0.029 0.25 0.08 

SH-1/22-AD 0.025 0.025 0.22 0.05 

SH-1/23-AD 0.020 0.020 0.15 0.05 

25
26

Appendix 6. Results of carbon and sulfur analyses—Continued

Sample Sulfur Sulfur (corr) Total Carbon Carbonate Carbon 

(wt.%) (wt.%) (wt.%) (wt.%) 

SH-1/24-AD 0.046 0.040 0.12 0.05 

SH-1/25-AD 0.051 0.043 0.19 0.04 

SH-1/26-AD 0.048 0.024 0.14 0.07 

SH-1/27-AD 0.048 0.048 0.24 0.05 

SH-1/28a-AD 0.034 0.029 0.30 0.05 

SH-1/28b-AD 0.037 0.037 0.30 nd 

SH-1/29-AD 0.055 0.046 0.28 0.1 

SH-1/30-AD 0.031 0.031 0.12 0.04 

SH-1/31-AD 0.034 0.034 0.09 nd 

SH-1/32-AD 0.120 0.120 0.40 0.12 

SH-1/33-AD 0.170 0.170 0.30 0.14 

SH-1/34b-AD 0.57 0.57 0.70 0.04 

SH-1/34m-AD 1.47 1.47 1.50 nd 

SH-1/35-AD 0.047 0.015 0.05 0.05 

SH-1/36-AD 0.038 0.028 0.15 nd 

SH-1/37-AD 0.079 0.048 0.13 0.05 

SH-1/38-AD 0.024 0.016 0.06 0.05 

SH-1/39a-AD 0.131 0.131 0.43 0.12 

SH-1/39b-AD 0.039 0.033 0.05 0.05 

SH-1/40-AD 0.033 0.017 0.08 0.07 
Appendix 7. Results of Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) analyses of air drie

BWDB (TH/S) and GSB (SH-1/) boreholes from Srirampur, Kachua. 

[Paul Briggs, Analyst] 

Sample Al Ca Fe K Mg Na P Ti Ag As Au Ba 

wt. % wt. % wt. % wt. % wt. % wt. % wt. % wt. % ppm ppm ppm ppm 

TH/S 20-AD 6.6 1.1 4.0 2.1 1.1 1.2 0.074 0.37 <2 <10 <8 460 TH/S 60-AD 4.7 1.4 2.0 1.6 0.60 1.3 0.056 0.26 <2 <10 <8 340 

TH/S 110-AD 4.6 1.4 2.1 1.6 0.59 1.2 0.059 0.27 <2 <10 <8 340 TH/S 120-AD 5.6 1.1 2.4 2.0 0.78 1.4 0.035 0.24 <2 <10 <8 420 TH/S 140-AD 4.7 1.3 2.4 1.6 0.64 1.2 0.065 0.29 <2 <10 <8 350 TH/S 160-AD 8.5 0.32 4.9 2.1 0.67 0.61 0.037 0.47 <2 11 <8 540 TH/S 170-AD 3.8 1.0 1.8 1.4 0.42 1.0 0.036 0.21 <2 <10 <8 310 TH/S 180-AD 4.8 1.4 2.2 1.6 0.65 1.2 0.058 0.28 <2 <10 <8 340 TH/S 210-AD 4.0 1.2 2.1 1.4 0.49 1.0 0.047 0.25 <2 <10 <8 310 TH/S 230-AD 3.5 0.99 2.1 1.3 0.39 0.90 0.044 0.24 <2 <10 <8 300 TH/S 320-AD 3.1 0.78 1.5 1.3 0.32 0.77 0.030 0.2 <2 <10 <8 280 TH/S 360-AD 2.9 0.53 1.3 1.3 0.28 0.63 0.020 0.17 <2 <10 <8 280 TH/S 380-AD 2.7 0.58 1.5 1.2 0.26 0.61 0.032 0.17 <2 <10 <8 380 TH/S 400-AD 2.7 0.56 1.3 1.3 0.26 0.60 0.020 0.17 <2 <10 <8 270 

SH-1/1-AD 6.6 1.3 3.5 2.2 1.2 1.4 0.051 0.36 <2 <10 <8 450 SH-1/2-AD 6.5 1.2 3.4 2.2 1.1 1.4 0.048 0.35 <2 <10 <8 440 SH-1/3-AD 7.6 1.4 4.5 2.3 1.6 1.2 0.068 0.48 <2 <10 <8 480 SH-1/4-AD 3.6 0.61 4.2 1.4 0.43 0.55 0.064 0.24 <2 <10 <8 300 SH-1/5-AD 9.8 0.39 5.1 2.3 0.92 0.63 0.043 0.52 <2 <10 <8 540 SH-1/6-AD 3.1 0.26 0.87 1.5 0.16 0.52 0.008 0.09 <2 <10 <8 300 SH-1/7-AD 4.8 0.68 2.5 1.8 0.34 1.1 0.026 0.15 <2 <10 <8 370 SH-1/8-AD 8.1 0.32 4.4 2.1 0.86 0.56 0.030 0.46 <2 10 <8 410 SH-1/9-AD 4.4 0.5 1.6 1.8 0.28 0.84 0.019 0.16 <2 <10 <8 380 

SH-1/10-AD 4.3 0.52 2.4 1.6 0.32 0.80 0.026 0.20 <2 <10 <8 310 SH-1/11-AD 3.8 0.47 4.0 1.6 0.24 0.68 0.024 0.17 <2 <10 <8 300 SH-1/12-AD 5.8 0.82 3.6 1.9 0.75 1.00 0.039 0.29 <2 <10 <8 550 

27
Appendix 7. Results of ICP-AES analyses—Continued

Sample Al Ca Fe K Mg Na P Ti Ag As Au Ba 

wt. % wt. % wt. % wt. % wt. % wt. % wt. % wt. % ppm ppm ppm ppm 

SH-1/13-AD 4.8 0.53 2.4 1.7 0.52 0.93 0.029 0.25 <2 <10 <8 340 

SH-1/14-AD 7.0 0.48 4.2 2.2 0.97 0.89 0.051 0.40 <2 <10 <8 430 SH-1/15-AD 3.7 0.46 1.4 1.5 0.21 0.78 0.016 0.13 <2 <10 <8 470 SH-1/16-AD 5.0 0.68 2.1 1.8 0.30 1.20 0.022 0.16 <2 <10 <8 360 SH-1/17-AD 8.0 0.37 6.9 2.2 1.20 0.53 0.019 0.44 <2 <10 <8 430 SH-1/18-AD 4.9 0.63 1.2 1.9 0.27 1.20 0.017 0.14 <2 <10 <8 380 SH-1/19-AD 4.7 0.58 2.8 1.8 0.29 1.10 0.018 0.14 <2 10 <8 360 SH-1/20-AD 4.5 0.65 4.3 1.6 0.29 1.00 0.022 0.14 <2 <10 <8 310 SH-1/21-AD 5.0 1.00 2.2 1.6 0.38 1.10 0.043 0.29 <2 <10 <8 340 SH-1/22-AD 4.7 0.76 1.9 1.7 0.32 1.10 0.022 0.16 <2 <10 <8 320 SH-1/23-AD 4.3 0.64 1.4 1.6 0.28 1.00 0.019 0.14 <2 <10 <8 320 SH-1/24-AD 4.5 0.92 2.2 1.4 0.36 0.99 0.032 0.28 <2 <10 <8 570 SH-1/25-AD 4.2 0.47 1.4 1.8 0.26 0.99 0.017 0.11 <2 <10 <8 710 SH-1/26-AD 4.7 0.79 1.5 1.6 0.36 1.10 0.026 0.17 <2 <10 <8 1300 SH-1/27-AD 5.3 1.00 2.7 1.8 0.47 1.20 0.05 0.36 <2 <10 <8 490 

SH-1/28a-AD 4.8 0.76 2.4 1.7 0.36 1.10 0.027 0.20 <2 <10 <8 550 

SH-1/28b-AD 4.9 0.79 2.3 1.8 0.36 1.10 0.028 0.20 <2 <10 <8 550 

SH-1/29-AD 4.8 0.59 2.0 2.0 0.33 1.10 0.023 0.15 <2 <10 <8 800 SH-1/30-AD 4.8 0.73 1.4 1.8 0.34 1.20 0.026 0.16 <2 <10 <8 430 SH-1/31-AD 4.9 0.92 1.6 1.7 0.38 1.20 0.035 0.22 <2 <10 <8 320 SH-1/32-AD 7.1 0.51 3.9 2.2 1.00 0.76 0.051 0.34 <2 <10 <8 420 SH-1/33-AD 7.4 0.45 4.1 2.2 1.10 0.75 0.036 0.39 <2 10 <8 560 

SH-1/34m-AD 7.4 0.60 7.4 2.9 1.90 0.97 0.033 0.55 <2 230 <8 440 

SH-1/34b-AD 5.9 0.63 4.3 2.1 1.10 0.98 0.032 0.36 <2 74 <8 410 

SH-1/35-AD 4.9 1.20 2.3 1.6 0.56 1.20 0.042 0.29 <2 <10 <8 1700 SH-1/36-AD 4.9 0.63 1.5 2.2 0.31 1.30 0.02 0.12 <2 14 <8 870 SH-1/37-AD 4.4 0.69 1.6 1.6 0.34 0.98 0.021 0.16 <2 10 <8 1600 SH-1/38-AD 4.4 0.98 1.9 1.6 0.40 1.00 0.028 0.22 <2 <10 <8 670 

SH-1/39a-AD 7.2 0.54 4.5 2.3 1.00 0.88 0.044 0.37 <2 <10 <8 480 

SH-1/39b-AD 4.6 0.79 1.6 1.6 0.40 1.00 0.026 0.21 <2 <10 <8 590 

SH-1/40-AD 4.0 0.69 1.6 1.4 0.34 0.88 0.024 0.20 <2 <10 <8 960 

28
Appendix 7. Results of ICP-AES—Continued

Sample Cd Ce Co Cr Cu Eu Ga Ho La Li Mn Mo 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

TH/S 20-AD <2 76 15 76 22 <2 15 <4 40 32 990 2.7 TH/S 60-AD <2 71 6.2 41 2.5 <2 10 <4 38 12 470 <2 

TH/S 110-AD <2 81 3.4 35 3.1 <2 10 <4 43 12 500 <2 TH/S 120-AD <2 41 9.7 38 4.6 <2 12 <4 23 20 390 <2 TH/S 140-AD <2 86 8.4 48 5.4 <2 10 <4 46 14 560 <2 TH/S 160-AD <2 79 13 96 24 <2 19 <4 39 42 530 2.5 TH/S 170-AD <2 66 4 31 2.3 <2 8.0 <4 35 9.5 570 <2 TH/S 180-AD <2 83 4.2 43 3.1 <2 10 <4 44 13 500 <2 TH/S 210-AD <2 75 4.8 41 3.6 <2 8.3 <4 41 10 570 <2 TH/S 230-AD <2 74 4.3 40 3.1 <2 6.9 <4 39 9.2 760 <2 TH/S 320-AD <2 59 2.2 26 2 <2 6.2 <4 31 8.5 420 <2 TH/S 360-AD <2 45 2.8 24 2.4 <2 6.0 <4 25 9.4 310 <2 TH/S 380-AD <2 52 3.7 22 3.3 <2 5.6 <4 28 8.2 570 <2 TH/S 400-AD <2 55 1.4 21 2.3 <2 5.6 <4 29 8.4 360 <2 

SH-1/1-AD <2 63 15 66 24 <2 13 <4 32 29 600 2.0 SH-1/2-AD <2 57 16 58 19 <2 13 <4 30 27 580 2.0 SH-1/3-AD <2 93 20 95 50 <2 17 <4 48 38 910 2.9 SH-1/4-AD <2 80 12 43 9 <2 5.8 <4 40 15 1200 <2 SH-1/5-AD <2 94 21 128 30 <2 24 <4 48 56 560 3.0 SH-1/6-AD <2 29 5.3 25 4.1 <2 7.9 <4 14 9.8 82 <2 SH-1/7-AD <2 34 7.8 24 187 <2 9.8 <4 18 14 890 <2 SH-1/8-AD <2 84 21 112 30 <2 18 <4 42 49 840 <2 SH-1/9-AD <2 48 8.4 32 5.1 <2 11 <4 24 13 420 2.0 

SH-1/10-AD <2 53 16 32 66 <2 9.0 <4 27 15 1000 <2 SH-1/11-AD <2 58 12 26 111 <2 8.1 <4 30 13 2700 <2 SH-1/12-AD <2 60 21 53 26 <2 12 <4 31 23 1200 2.0 

29
Appendix 7. Results of ICP-AES—Continued

Sample Cd Ce Co Cr Cu Eu Ga Ho La Li Mn Mo 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

SH-1/13-AD <2 53 11 46 6.7 <2 9.1 <4 27 21 530 <2 

SH-1/14-AD <2 70 17 87 22 <2 15 <4 35 42 840 2.0 SH-1/15-AD 2.9 40 5.7 20 3.8 <2 9.3 <4 20 12 470 <2 SH-1/16-AD <2 38 6.9 23 4.1 <2 12 <4 20 16 840 <2 SH-1/17-AD <2 75 18 84 34 <2 23 <4 39 48 1800 2.8 SH-1/18-AD <2 39 6 23 2.0 <2 12 <4 21 15 240 <2 SH-1/19-AD <2 33 10 24 4.9 <2 10 <4 17 15 1000 <2 SH-1/20-AD <2 38 122 20 40 <2 8.3 <4 20 13 1900 <2 SH-1/21-AD <2 96 6.3 39 19 <2 12 <4 50 14 740 <2 SH-1/22-AD <2 44 7 25 2.8 <2 11 <4 23 13 570 <2 SH-1/23-AD <2 42 5.9 23 4.0 <2 9.9 <4 22 13 380 <2 SH-1/24-AD <2 110 6.5 36 2.4 <2 9.9 <4 56 13 950 <2 SH-1/25-AD <2 34 6.2 19 2.6 <2 9.7 <4 18 14 340 <2 SH-1/26-AD <2 51 6.6 28 5.2 <2 11 <4 27 14 340 <2 SH-1/27-AD <2 99 8 44 3.7 <2 12 <4 52 19 850 <2 

SH-1/28a-AD <2 49 7.2 29 8.8 <2 10 <4 26 14 760 <2 

SH-1/28b-AD <2 53 7.4 31 7.6 <2 11 <4 28 15 760 <2 

SH-1/29-AD <2 34 6.3 24 6.2 <2 11 <4 18 16 620 <2 SH-1/30-AD <2 36 5.7 26 2.7 <2 11 <4 19 14 330 <2 SH-1/31-AD <2 59 5.6 32 1.8 <2 11 <4 31 14 420 <2 SH-1/32-AD <2 64 16 85 28 <2 14 <4 33 48 830 2.1 SH-1/33-AD <2 66 17 99 42 <2 14 <4 33 55 530 2.3 

SH-1/34m-AD <2 46 40 94 33 <2 <4 <4 24 83 800 4.8 

SH-1/34b-AD <2 44 22 72 19 <2 5.1 <4 22 44 560 3.0 

SH-1/35-AD <2 98 7.4 50 2.5 <2 4.4 <4 49 14 600 2.5 SH-1/36-AD <2 30 7 20 7.9 <2 6.4 <4 15 16 430 2.6 SH-1/37-AD <2 40 6.5 28 3.0 <2 4.3 <4 20 11 390 2.6 SH-1/38-AD <2 86 5.8 31 1.4 <2 <4 <4 42 12 630 <2 

SH-1/39a-AD <2 67 18 77 14 <2 4.4 <4 34 45 1000 3.3 

SH-1/39b-AD <2 61 6.6 30 5.2 <2 5.5 <4 30 14 390 2.6 

SH-1/40-AD <2 52 6.3 30 4.4 <2 4.5 <4 25 11 380 <2 

30
Appendix 7. Results of ICP-AES analyses—Continued

Sample Pb Sc Sn Sr Ta Th U V Y Yb Zn 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

TH/S 20-AD 17 11 <5 140 <20 17 <100 79 20 2.3 64 TH/S 60-AD 15 7.4 <5 150 <20 15 <100 51 21 2.4 35 

TH/S 110-AD 12 7.6 <5 150 <20 18 <100 51 22 2.4 32 TH/S 120-AD 18 7.2 <5 150 <20 9.2 <100 53 12 1.3 45 TH/S 140-AD 14 8 <5 150 <20 20 <100 54 21 2.4 41 TH/S 160-AD 27 14 <5 82 <20 21 <100 113 18 2.4 75 TH/S 170-AD 15 5.5 <5 130 <20 14 <100 38 15 1.6 27 TH/S 180-AD 14 8 <5 150 <20 18 <100 54 21 2.3 35 TH/S 210-AD 15 6.6 <5 140 <20 22 <100 44 19 2.2 32 TH/S 230-AD 14 5.5 <5 120 <20 17 <100 39 17 1.7 27 TH/S 320-AD 13 4.5 <5 100 <20 16 <100 32 13 1.5 22 TH/S 360-AD 13 3.6 <5 81 <20 9.4 <100 26 10 1.1 20 TH/S 380-AD 12 3.7 9.9 84 <20 10 <100 28 11 1.2 19 TH/S 400-AD 12 3.6 19 80 <20 12 <100 25 12 1.2 17 

SH-1/1-AD 19 12 5 150 <40 13 <100 77 19 1.9 76 SH-1/2-AD 19 11 <5 150 <40 11 <100 72 17 1.6 66 SH-1/3-AD 24 16 7.3 140 <40 19 <100 104 27 2.7 95 SH-1/4-AD 15 6.3 <5 80 <40 22 <100 47 16 1.5 37 SH-1/5-AD 27 19 5.9 90 <40 18 <100 135 29 2.7 95 SH-1/6-AD 16 3.5 <5 67 <40 4.4 <100 27 6.3 <1 18 SH-1/7-AD 16 6 <5 120 <40 6.3 <100 39 11 1.2 120 SH-1/8-AD 24 16 6.2 77 <40 15 <100 110 25 2.3 94 SH-1/9-AD 18 5.7 <5 96 <40 8.5 <100 34 13 1.3 25 

SH-1/10-AD 16 6.2 <5 93 <40 10 <100 40 12 1.2 76 SH-1/11-AD 15 6 <5 75 <40 12 <100 36 16 1.8 90 SH-1/12-AD 19 10 <5 120 <40 11 <100 64 18 1.8 72 

31
Appendix 7. Results of ICP-AES analyses—Continued

Sample Pb Sc Sn Sr Ta Th U V Y Yb Zn 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

SH-1/13-AD 17 7.9 <5 95 <40 11 <100 52 18 1.5 130 

SH-1/14-AD 22 13 6.3 96 <40 13 <100 93 20 1.9 86 SH-1/15-AD 17 4.7 <5 90 <40 7.5 <100 28 12 1.2 30 SH-1/16-AD 20 5.6 <5 130 <40 7.4 <100 34 12 1.1 29 SH-1/17-AD 24 16 6.7 75 <40 16 <100 104 25 2.5 94 SH-1/18-AD 19 5.3 <5 130 <40 7.4 <100 34 9.9 1.0 30 SH-1/19-AD 19 5.5 <5 120 <40 7.3 <100 34 11 1.1 27 SH-1/20-AD 16 5.9 <5 110 <40 7.5 <100 32 13 1.3 47 SH-1/21-AD 19 8.8 <5 140 <40 19 <100 52 27 2.8 36 SH-1/22-AD 16 5.8 <5 120 <40 8.0 <100 35 13 1.3 23 SH-1/23-AD 17 5.2 <5 120 <40 8.0 <100 31 12 1.2 22 SH-1/24-AD 15 9.4 <5 130 <40 20 <100 47 31 3.6 26 SH-1/25-AD 18 4.4 <5 110 <40 6.8 <100 28 8.9 <1 20 SH-1/26-AD 16 6.8 <5 160 <40 9.6 <100 42 14 1.4 26 SH-1/27-AD 18 10 <5 140 <40 23 <100 68 28 2.8 37 

SH-1/28a-AD 15 7.0 <5 140 <40 11 <100 44 15 1.5 32 

SH-1/28b-AD 15 7.1 <5 140 <40 10 <100 44 15 1.5 30 

SH-1/29-AD 17 5.6 <5 130 <40 7.0 <100 34 9.5 1.0 31 SH-1/30-AD 15 5.8 <5 130 <40 7.9 <100 38 10 1.0 26 SH-1/31-AD 16 7.1 <5 140 <40 15 <100 45 17 1.7 27 SH-1/32-AD 22 13 <5 98 <40 13 <100 90 20 1.9 79 SH-1/33-AD 22 14 5.5 100 <40 13 <100 100 19 2.0 91 

SH-1/34m-AD 38 16 14 120 <20 9.0 <100 120 23 2.4 150 

SH-1/34b-AD 22 12 7.9 110 <20 15 <100 78 17 1.7 90 

SH-1/35-AD 13 9.1 <5 170 <20 24 <100 56 24 2.6 41 SH-1/36-AD 34 4.3 <5 150 <20 <4 <100 28 7.5 <1 32 SH-1/37-AD 17 5.0 <5 140 <20 8.9 <100 34 12 1.2 36 SH-1/38-AD 14 7.1 <5 130 <20 19 <100 42 22 2.5 28 

SH-1/39a-AD 18 13 8.0 100 <20 14 <100 87 17 1.7 74 

SH-1/39b-AD 19 5.8 6.0 130 <20 11 <100 38 14 1.4 32 

SH-1/40-AD 19 5.3 6.1 120 <20 14 <100 35 14 1.6 39 

32
Appendix 8. Results of Energy Dispersive X-ray Fluorescence (EDXRF) analyses of air-dried sediment samples re

BWDB (TH/S) and GSB (SH-1/) boreholes at Srirampur, Kachua. 

[David Siems and Tammy Hannah, Analysts] 

Sample Ag As Ba Bi Br Cd Ce Cr Cs Cu Ga 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

TH/S 20-AD <1 6 440 <5 <1 <1 84 72 8 26 15 

TH/S 60-AD <1 <2 360 <5 <1 <1 91 40 6 9 11 

TH/S 110-AD <1 <2 350 <5 <1 <1 88 41 <5 9 10 TH/S 120-AD <1 <2 360 <5 <1 <1 97 44 <5 14 11 TH/S 140-AD <1 8 490 <5 <1 <1 85 110 10 28 18 TH/S 160-AD <1 <2 330 <5 <1 <1 71 41 <5 8 10 TH/S 170-AD <1 <2 360 <5 <1 <1 95 46 6 10 10 TH/S 180-AD <1 2 330 <5 <1 <1 93 43 5 9 8 TH/S 210-AD <1 <2 430 <5 <1 <1 47 38 9 10 12 TH/S 230-AD <1 <2 320 <5 <1 <1 88 39 <5 9 8 TH/S 320-AD <1 <2 300 <5 <1 <1 76 32 <5 8 9 TH/S 360-AD <1 <2 300 <5 <1 <1 65 30 6 6 7 TH/S 380-AD <1 <2 300 <5 <1 <1 70 27 <5 8 6 TH/S 400-AD <1 <2 290 <5 <1 <1 74 25 6 6 5 

SH-1/1-AD <1 7 450 <5 <1 <1 65 76 9 26 18 SH-1/2-AD <1 3 450 <5 <1 <1 64 66 10 24 16 SH-1/3-AD <1 7 480 <5 <1 2 95 120 11 56 21 SH-1/4-AD <1 6 320 <5 <1 <1 87 73 <5 14 9 SH-1/5-AD <1 6 530 <5 <1 <1 98 140 11 31 24 SH-1/6-AD <1 <2 340 <5 <1 <1 42 27 7 6 7 SH-1/7-AD <1 <2 400 <5 <1 <1 44 29 6 190 11 SH-1/8-AD <1 10 410 <5 <1 <1 93 140 11 39 21 SH-1/9-AD <1 3 420 <5 <1 <1 63 35 7 9 10 

SH-1/10-AD <1 4 340 <5 <1 <1 55 40 7 74 11 SH-1/11-AD <1 4 330 <5 <1 <1 62 35 <5 73 10 SH-1/12-AD <1 5 550 <5 <1 <1 63 65 8 34 14 

33
Appendix 8. Results of EDXRF analyses—Continued.

Sample Ag As Ba Bi Br Cd Ce Cr Cs Cu Ga 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

SH-1/13-AD <1 6 370 <5 <1 <1 65 63 7 10 11 

SH-1/14-AD <1 9 430 <5 <1 <1 80 110 9 20 15 SH-1/15-AD <1 2 500 <5 <1 3 49 23 8 5 10 SH-1/16-AD <1 2 390 <5 <1 <1 44 28 6 7 11 SH-1/17-AD <1 <2 430 <5 <1 <1 74 120 11 38 22 SH-1/18-AD <1 <2 410 <5 <1 <1 50 23 8 3 11 SH-1/19-AD <1 5 380 <5 <1 <1 42 33 5 8 10 SH-1/20-AD <1 3 340 <5 <1 <1 40 32 <5 38 9 SH-1/21-AD <1 3 370 <5 <1 <1 119 42 7 21 11 SH-1/22-AD <1 2 360 <5 <1 <1 55 34 6 6 11 SH-1/23-AD <1 <2 360 <5 <1 <1 58 27 7 6 10 SH-1/24-AD <1 3 590 <5 <1 <1 120 44 7 5 11 SH-1/25-AD <1 4 750 <5 <1 <1 44 23 9 4 11 SH-1/26-AD <1 <2 1400 <5 <1 <1 63 38 15 8 11 SH-1/27-AD <1 4 510 <5 <1 <1 120 60 6 7 12 

SH-1/28a-AD <1 2 580 <5 1 <1 64 36 8 11 11 

SH-1/28b-AD <1 2 580 <5 <1 <1 71 39 11 9 12 

SH-1/29-AD <1 3 820 <5 <1 <1 47 29 11 11 11 SH-1/30-AD <1 <2 460 <5 2 <1 47 33 8 5 11 SH-1/31-AD <1 <2 350 <5 2 <1 67 40 6 3 11 SH-1/32-AD <1 8 430 <5 3 <1 73 104 12 30 16 SH-1/33-AD <1 11 560 <5 <1 <1 81 120 14 42 19 

SH-1/34m-AD <1 190 410 <5 2 <1 43 120 18 34 21 

SH-1/34b-AD <1 67 420 <5 <1 <1 48 86 10 22 16 

SH-1/35-AD <1 <2 1700 <5 <1 <1 110 53 8 9 13 SH-1/36-AD <1 2 890 <5 <1 <1 49 25 14 11 10 SH-1/37-AD <1 5 1700 <5 <1 <1 60 34 18 8 9 SH-1/38-AD <1 <2 690 <5 <1 <1 95 40 6 4 9 

SH-1/39a-AD <1 11 480 <5 <1 <1 68 92 8 18 15 

SH-1/39b-AD <1 2 600 <5 <1 <1 72 39 7 8 12 

SH-1/40-AD <1 <2 990 <5 <1 <1 72 34 12 8 9 

34
Appendix 8. Results of EDXRF analyses—Continued

Sample Mo Nb Nd Ni Pb Rb Sb Se Sn Sr Th 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

TH/S 20-AD <2 14 33 45 23 128 <2 <1 4 140 18 

TH/S 60-AD <2 10 39 23 16 79 <2 <1 5 160 10 

TH/S 110-AD <2 10 39 21 18 80 <2 <1 2 160 17 TH/S 120-AD <2 12 39 31 17 83 <2 <1 3 160 17 TH/S 140-AD <2 17 32 59 28 138 <2 <1 4 86 20 TH/S 160-AD <2 8 33 14 15 69 <2 <1 <2 140 11 TH/S 170-AD <2 10 38 25 17 82 <2 <1 2 160 12 TH/S 180-AD <2 9 42 22 14 71 <2 <1 3 150 16 TH/S 210-AD <2 9 23 32 18 120 <2 <1 <2 150 7 TH/S 230-AD <2 9 36 20 14 63 <2 <1 <2 130 9 TH/S 320-AD <2 7 38 21 14 62 <2 <1 <2 109 11 TH/S 360-AD <2 7 36 13 13 64 <2 <1 <2 89 9 TH/S 380-AD <2 6 33 14 13 58 <2 <1 <2 92 8 TH/S 400-AD <2 6 40 11 12 60 <2 <1 <2 86 9 

SH-1/1-AD <2 13 25 37 21 139 <2 <1 4 150 12 SH-1/2-AD <2 13 31 34 20 139 <2 <1 3 150 11 SH-1/3-AD <2 18 37 47 26 152 <2 <1 4 140 19 SH-1/4-AD <2 8 33 24 20 76 <2 <1 2 84 17 SH-1/5-AD <2 18 45 68 28 165 <2 <1 5 90 21 SH-1/6-AD <2 4 24 12 14 70 <2 <1 <2 69 4 SH-1/7-AD <2 6 20 13 20 90 <2 <1 4 130 6 SH-1/8-AD <2 18 40 67 26 140 <2 <1 4 82 19 SH-1/9-AD <2 7 31 13 19 90 <2 <1 2 102 8 

SH-1/10-AD <2 8 25 19 19 83 <2 <1 3 99 8 SH-1/11-AD <2 8 16 15 20 80 <2 <1 2 82 10 SH-1/12-AD <2 11 24 27 23 120 <2 <1 3 120 12 

35
Appendix 8. Results of EDXRF—Continued

Sample Mo Nb Nd Ni Pb Rb Sb Se Sn Sr Th 

ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm 

SH-1/13-AD <2 10 30 28 19 95 <2 <1 2 99 11 

SH-1/14-AD <2 15 36 42 24 140 <2 <1 4 98 16 SH-1/15-AD <2 6 18 9 18 78 <2 <1 <2 93 8 SH-1/16-AD <2 7 25 13 21 94 <2 <1 <2 130 7 SH-1/17-AD <2 15 25 40 29 150 <2 <1 4 78 18 SH-1/18-AD <2 6 33 12 19 94 <2 <1 <2 130 6 SH-1/19-AD <2 6 22 16 20 89 <2 <1 <2 120 7 SH-1/20-AD <2 6 18 9 19 81 <2 <1 2 120 7 SH-1/21-AD <2 10 56 13 19 80 <2 <1 3 140 18 SH-1/22-AD <2 7 29 12 18 82 <2 <1 <2 130 8 SH-1/23-AD <2 5 28 9 16 78 <2 <1 <2 120 6 SH-1/24-AD <2 11 47 12 17 74 <2 <1 3 130 21 SH-1/25-AD <2 5 22 12 18 92 <2 <1 2 120 <4 SH-1/26-AD <2 7 50 12 18 84 <2 <1 3 160 8 SH-1/27-AD <2 14 44 20 19 97 <2 <1 3 150 21 

SH-1/28a-AD <2 8 36 15 17 91 <2 <1 3 140 10 

SH-1/28b-AD <2 9 36 14 17 89 <2 <1 2 140 11 

SH-1/29-AD <2 7 31 13 18 98 <2 <1 2 130 6 SH-1/30-AD <2 7 30 12 16 87 <2 <1 <2 140 7 SH-1/31-AD <2 9 33 13 17 80 <2 <1 3 140 12 SH-1/32-AD <2 13 28 44 26 130 <2 <1 3 99 15 SH-1/33-AD <2 14 47 50 26 130 <2 <1 3 100 11 

SH-1/34m-AD 4 16 19 87 33 240 <2 <1 6 90 9 

SH-1/34b-AD <2 15 16 52 24 160 <2 <1 4 110 10 

SH-1/35-AD <2 11 59 21 18 75 <2 <1 5 160 20 SH-1/36-AD <2 6 43 10 18 90 <2 <1 2 130 <4 SH-1/37-AD <2 6 43 16 17 81 <2 <1 3 140 7 SH-1/38-AD 2 8 39 15 15 72 <2 <1 5 130 17 

SH-1/39a-AD <2 15 26 43 21 140 <2 <1 4 99 14 

SH-1/39b-AD 2 8 28 15 17 84 <2 <1 2 130 9 

SH-1/40-AD <2 7 44 14 17 78 <2 <1 3 130 9 

36
Appendix 8. Results of EDXRF analyses—Continued

Sample V W Y Zn Zr 

ppm ppm ppm ppm ppm 

TH/S 20-AD 87 <5 34 66 230 

TH/S 60-AD 49 <5 28 44 280 

TH/S 110-AD 52 <5 32 40 280 TH/S 120-AD 60 <5 31 50 330 TH/S 140-AD 120 <5 33 76 250 TH/S 160-AD 35 <5 23 35 240 TH/S 170-AD 57 <5 30 42 300 TH/S 180-AD 44 <5 27 41 300 TH/S 210-AD 54 <5 17 48 120 TH/S 230-AD 37 <5 25 36 320 TH/S 320-AD 35 <5 20 31 230 TH/S 360-AD 29 <5 16 27 170 TH/S 380-AD 32 <5 15 28 190 TH/S 400-AD 31 <5 17 27 200 

SH-1/1-AD 81 <5 26 78 190 SH-1/2-AD 73 <5 22 70 170 SH-1/3-AD 110 <5 37 99 270 SH-1/4-AD 55 <5 26 43 360 SH-1/5-AD 139 <5 37 93 190 SH-1/6-AD 27 <5 10 20 86 SH-1/7-AD 36 <5 14 130 100 SH-1/8-AD 120 <5 39 96 280 SH-1/9-AD 37 <5 16 29 110 

SH-1/10-AD 43 <5 17 86 140 SH-1/11-AD 39 <10 20 80 140 SH-1/12-AD 72 40 25 93 180 

37
38

Appendix 8. Results of EDXRF analyses—Continued

Sample V W Y Zn Zr 

ppm ppm ppm ppm ppm 

SH-1/13-AD 52 <5 22 140 250 

SH-1/14-AD 110 <5 32 89 270 SH-1/15-AD 32 <5 15 35 100 SH-1/16-AD 34 <5 14 35 110 SH-1/17-AD 110 <5 34 110 190 SH-1/18-AD 35 <5 13 33 100 SH-1/19-AD 40 <5 15 33 98 SH-1/20-AD 35 <10 14 54 100 SH-1/21-AD 59 <5 32 46 220 SH-1/22-AD 39 <5 16 29 110 SH-1/23-AD 29 <5 15 27 100 SH-1/24-AD 53 <5 38 39 230 SH-1/25-AD 29 <5 12 24 96 SH-1/26-AD 46 <5 18 33 100 SH-1/27-AD 77 <5 38 47 350 

SH-1/28a-AD 47 <5 19 36 150 

SH-1/28b-AD 46 <5 20 35 160 

SH-1/29-AD 37 <5 13 36 110 SH-1/30-AD 37 <5 15 31 120 SH-1/31-AD 46 <5 22 30 180 SH-1/32-AD 100 <5 29 88 220 SH-1/33-AD 110 <5 27 96 230 

SH-1/34m-AD 120 <5 29 130 140 

SH-1/34b-AD 81 <10 23 88 190 

SH-1/35-AD 59 <5 33 47 270 SH-1/36-AD 28 <10 10 31 78 SH-1/37-AD 36 <5 15 39 140 SH-1/38-AD 38 <5 27 34 140 

SH-1/39a-AD 96 <5 28 75 230 

SH-1/39b-AD 42 <5 19 34 160 

SH-1/40-AD 35 <5 22 38 160 
Appendix 9. Results of arsenic analyses by Hydride Generation Atomic Absorption 

Spectrophotometery (HGAAS) of air-dried sediment samples from the BWDB (TH/S) and GSB (SH-1/) 

boreholes sediment from Srirampur, Kachua. 

 [Zoe Ann Brown, Analyst] 

Sample As Sample As 

ppm ppm 

TH/S 20-AD 7.8 SH-1/15-AD 1.9 

TH/S 60-AD 1.8 SH-1/16-AD 2.1 

TH/S 110-AD 2.0 SH-1/17-AD 1.2 

TH/S 120-AD 2.1 SH-1/18-AD 1.6 

TH/S 140-AD 2.9 SH-1/19-AD 4.3 

TH/S 160-AD 11 SH-1/20-AD 3.0 

TH/S 170-AD 1.4 SH-1/21-AD 2.8 

TH/S 180-AD 2.1 SH-1/22-AD 1.9 

TH/S 210-AD 1.8 SH-1/23-AD 1.9 

TH/S 230-AD 1.8 SH-1/24-AD 3.3 

TH/S 320-AD 1.7 SH-1/25-AD 3.2 

TH/S 360-AD 1.8 SH-1/26-AD 1.9 

TH/S 380-AD 1.7 SH-1/27-AD 3.3 

TH/S 400-AD 1.3 SH-1/28a-AD 2.3 

SH-1/28b-AD 2.4 

SH-1/1-AD 6.4 SH-1/29-AD 3.7 

SH-1/2-AD 3.3 SH-1/30-AD 1.6 

SH-1/3-AD 7.6 SH-1/31-AD 1.8 

SH-1/4-AD 5.7 SH-1/32-AD 8.4 

SH-1/5-AD 5.9 SH-1/33-AD 12 

SH-1/6-AD 0.6 SH-1/34m-AD 210 

SH-1/7-AD 2.1 SH-1/34b-AD 71 

SH-1/8-AD 11 SH-1/35-AD 1.6 

SH-1/9-AD 2.7 SH-1/36-AD 3.1 

SH-1/10-AD 3.9 SH-1/37-AD 5.8 

SH-1/11-AD 4.4 SH-1/38-AD 1.6 

SH-1/12-AD 6.2 SH-1/39a-AD 12 

SH-1/13-AD 5.3 SH-1/39b-AD 2.7 

SH-1/14-AD 9.2 SH-1/40-AD 1.3 

39
Appendix 10. Concentrations of major cations extracted from preserved sediment samples from the 

GSB borehole at Srirampur, Kachua, with an aqueous solution of 0.1 molar SrCl2. Concentrations 

measured by ICP-AES. 

[Cyndi Rice, analyst]

Sample Ca Mg K Na Fe 

(ppm) (ppm) (ppm) (ppm) ppm 

SH-1/2-P 280 310 59 210 32 

SH-1/3-P 440 400 62 420 64 

SH-1/6-P 760 550 100 640 110 

SH-1/7-P 1540 730 94 700 350 

SH-1/8-P 200 63 25 200 0.3 

SH-1/10-P 260 75 21 230 0.3 

SH-1/12-P 150 44 130 300 3.1 

SH-1/13-P 260 61 85 340 5.4 

SH-1/16-P 250 200 85 500 0.6 

SH-1/17-P 700 480 110 740 <0.3 

SH-1/26-P 150 84 100 250 0.3 

SH-1/29-P 270 180 46 460 <0.3 

SH-1/30-P 140 97 38 370 <0.3 

SH-1/33-P 1400 920 170 960 <0.3 

SH-1/35-P 190 93 64 330 <0.3 

SH-1/41-P 460 280 74 170 <0.3 

40
Appendix 11. Total iron and ferrous iron extracted from air-dried sediment samples from the GSB 

bore-hole at Srirampur, Kachua, using an acid solution of 0.5N HCl. Concentrations determined 

spectrophotometrically. 

[nd, not determined.]

Sample Total Iron Ferrous Ferrous / Total Iron 

(wt. %) (wt.%) (wt. / wt.) 

SH-1/1-AD 0.91 0.66 0.72 

SH-1/2-AD 0.93 0.65 0.70 

SH-1/3-AD 1.21 0.85 0.71 

SH-1/4-AD 2.51 1.48 0.59 

SH-1/5-AD 1.09 0.43 0.40 

SH-1/6-AD 0.14 0.09 0.60 

SH-1/7-AD 1.35 1.25 0.93 

SH-1/8-AD 1.26 0.83 0.66 

SH-1/9-AD 0.48 0.34 0.71 

SH-1/10-AD 1.22 1.15 0.94 

SH-1/11-AD 3.31 3.03 0.92 

SH-1/12-AD 1.77 1.55 0.88 

SH-1/13-AD 0.78 0.66 0.85 

SH-1/14-AD 1.14 1.04 0.91 

SH-1/15-AD 0.48 0.38 0.79 

SH-1/16-AD 1.02 0.95 0.93 

SH-1/17-AD 2.05 1.79 0.87 

SH-1/18-AD 0.32 0.26 0.83 

SH-1/19-AD 1.37 1.42 1.01 

SH-1/20-AD 2.62 2.67 1.01 

SH-1/21-AD 0.50 0.45 0.90 

SH-1/22-AD 0.52 0.44 0.84 

SH-1/23-AD 0.30 0.25 0.84 

SH-1/24-AD 0.38 0.33 0.87 

SH-1/25-AD 0.48 0.42 0.89 

SH-1/26-AD 0.36 0.34 0.95 

SH-1/27-AD 0.97 0.9 0.93 

SH-1/28a-AD 1.23 1.22 0.99 

SH-1/28b-AD 1.12 1.05 0.94 

SH-1/29-AD nd nd nd 

SH-1/30-AD 0.46 0.43 0.94 

SH-1/31-AD 0.36 0.33 0.93 

SH-1/32-AD 1.14 0.96 0.85 

SH-1/33-AD 0.93 0.79 0.86 

SH-1/34m-AD nd nd nd 

SH-1/34b-AD nd nd nd 

SH-1/35-AD nd nd nd 

SH-1/36-AD nd nd nd 

SH-1/37-AD nd nd nd 

SH-1/38-AD nd nd nd 

SH-1/39a-AD nd nd nd 

SH-1/39b-AD nd nd nd 

SH-1/40-AD nd nd nd 

41
42

Appendix 12. Total and ferrous iron extracted from preserved sediment samples from the GSB borehole, Srirampur, Kachua, using an acid solution of 0.5N HCl. Concentrations determined 

spectrophotometrically. 

[concentrations on dry weight basis following extraction]

Total Iron Ferrous Ferrous / Total Iron 

(wt. %) (wt.%) (wt. / wt.) 

SH-1/1-P 0.76 0.74 0.98 

SH-1/2-P 0.90 0.89 0.98 

SH-1/3-P 1.33 1.25 0.94 

SH-1/4-P 1.52 1.35 0.89 

SH-1/5-P 0.48 0.29 0.62 

SH-1/6-P 2.15 2.16 1.00 

SH-1/7-P 2.62 2.59 0.99 

SH-1/8-P 0.11 0.11 0.93 

SH-1/9-P 1.84 1.87 1.01 

SH-1/10-P 0.22 0.22 0.99 

SH-1/11-P 2.36 2.42 1.01 

SH-1/12-P 0.15 0.15 1.00 

SH-1/13-P 2.87 2.78 0.97 

SH-1/14-P 1.42 1.40 0.99 

SH-1/15-P 0.85 0.83 0.98 

SH-1/16-P 0.63 0.61 0.96 

SH-1/17-P 1.07 1.08 1.01 

SH-1/18-P 0.49 0.48 0.98 

SH-1/19-P 0.18 0.17 0.97 

SH-1/20-P 0.29 0.28 0.97 

SH-1/21-P 0.86 0.85 0.99 

SH-1/22-P 6.25 6.29 1.01 

SH-1/23-P 0.71 0.69 0.97 

SH-1/24-P 0.21 0.20 0.92 

SH-1/25-P 0.39 0.38 0.99 

SH-1/26-P 0.45 0.45 1.01 

SH-1/27-P 0.52 0.51 0.98 

SH-1/28-P 0.44 0.43 0.98 

SH-1/29-P 1.77 1.77 1.00 

SH-1/30-P 0.71 0.66 0.94 

SH-1/31-P 0.91 0.85 0.94 

SH-1/32-P 0.43 0.43 0.99 

SH-1/33-P 1.41 1.38 0.98 

SH-1/34-P 1.19 1.13 0.95 

SH-1/35-P 0.57 0.55 0.96 

SH-1/36-P 1.58 1.48 0.94 

SH-1/37-P 0.39 0.37 0.96 

SH-1/38-P 0.48 0.46 0.96 

SH-1/39-P 0.45 0.44 0.96 

SH-1/40-P 0.22 0.21 0.96 

SH-1/41-P 0.93 0.93 1.00 

SH-1/42-P 0.15 0.13 0.91 
Appendix 13. Element concentrations extracted from preserved sediment samples from the GSB borehole, Sriram

an acid solution of 0.5 N HCl. Concentrations determined by ICP-AES unless otherwise indicated. [*, determined by HG-AAS, # determined by atomic absorption spectrophotometry. Values calculated based on dry weight of the post-

Sample Al As* B Ba Be Ca Cd Co Cr Cu 

(ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) 

SH-1/1-P 3000 0.25 2.0 25 0.21 1400 <0.2 5.4 4.8 6.9 

SH-1/2-P 2800 0.35 2.2 19 0.20 2200 <0.2 6.0 4.9 6.0 SH-1/3-P 4300 1.4 3.3 46 0.43 3500 <0.2 8.4 6.8 23 SH-1/4-P 4400 1.7 4.0 27 0.49 2400 <0.2 9.1 7.4 27 SH-1/5-P 790 0.57 1.4 6.9 0.15 160 <0.2 1.8 2.5 1.8 SH-1/6-P 3200 0.21 4.8 56 0.73 1900 <0.2 7.7 6.9 0.7 SH-1/7-P 6000 0.18 4.6 100 1.03 2500 <0.2 10.0 13.0 1.3 SH-1/8-P 380 0.06 0.4 4.1 0.08 320 <0.2 1.2 1.5 0.5 SH-1/9-P 2900 0.06 4.2 26 0.93 2200 <0.2 6.4 5.8 <0.2 

SH-1/10-P 730 0.14 0.7 9.2 0.12 470 <0.2 3.2 3.0 0.8 SH-1/11-P 1300 0.21 4.8 8.9 0.43 830 0.69 4.5 0.4 59 SH-1/12-P 710 0.45 0.7 5.0 0.14 450 <0.2 2.5 2.0 0.7 SH-1/13-P 1300 0.59 6.8 17 0.51 1100 0.86 5.5 <0.2 41 SH-1/14-P 1100 0.10 4.1 7.9 0.33 610 <0.2 2.9 0.9 2.5 SH-1/15-P 1900 0.21 3.2 16 0.38 1200 <0.2 4.8 4.2 2.5 SH-1/16-P 1300 0.68 2.3 24 0.33 860 <0.2 3.6 2.7 2.6 SH-1/17-P 2700 1.7 4.1 18 0.45 1600 <0.2 8.2 5.1 8.9 SH-1/18-P 480 0.56 2.1 65 0.14 480 2.11 2.5 1.1 2.1 SH-1/19-P 520 0.20 1.2 22 0.11 580 <0.2 1.5 1.6 1.1 SH-1/20-P 630 0.24 1.6 4.1 0.12 540 <0.2 2.2 1.9 0.6 SH-1/21-P 420 0.39 1.7 3.5 0.13 480 <0.2 2.0 0.8 1.0 SH-1/22-P 1200 0.41 14.4 43 0.75 1700 1.49 8.1 <0.2 33 SH-1/23-P 1500 0.39 1.9 11 0.24 1700 <0.2 3.2 2.9 6.1 SH-1/24-P 430 0.34 0.8 17 0.11 660 <0.2 1.7 1.5 1.1 SH-1/25-P 610 0.33 2.5 3.5 0.16 460 <0.2 2.5 0.8 0.7 SH-1/26-P 940 0.20 1.6 6.6 0.15 530 <0.2 1.8 1.7 2.3 

43
Appendix 13. Concentrations of elements extracted using 0.5 N HCl—Continued

Sample Al As* B Ba Be Ca Cd Co Cr Cu 

(ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) 

SH-1/27-P 400 0.49 1.6 100 0.13 430 <0.2 2.1 0.6 0.9 

SH-1/28-P 680 0.42 1.5 130 0.15 710 <0.2 2.5 1.5 2.3 SH-1/29-P 1800 1.3 4.9 8.7 0.40 1600 <0.2 5.8 3.0 2.7 SH-1/30-P 600 0.28 2.0 5.5 0.13 680 <0.2 2.2 1.5 1.0 SH-1/31-P 1000 0.32 3.2 130 0.17 760 <0.2 2.7 1.3 58 SH-1/32-P 680 0.13 1.5 2.3 0.11 710 <0.2 1.7 1.5 0.7 SH-1/33-P 3400 1.7 5.0 6.6 0.66 2900 <0.2 8.6 6.0 23 SH-1/34-P 2500 1.9 3.6 14.8 0.36 1800 <0.2 6.8 4.4 8.4 SH-1/35-P 610 0.11 1.6 230 0.12 710 <0.2 1.7 1.9 1.1 SH-1/36-P 4400 0.54 3.8 87.0 0.55 1200 <0.2 11.9 9.3 6.2 SH-1/37-P 840 0.18 1.2 260 0.11 1000 <0.2 2.2 3.2 1.5 SH-1/38-P 750 0.23 1.6 230 0.11 480 <0.2 3.2 1.9 7.7 SH-1/39-P 700 0.24 1.3 290 0.11 610 <0.2 2.1 2.8 2.0 SH-1/40-P 430 0.15 0.7 250 0.07 410 <0.2 1.4 1.7 1.0 SH-1/41-P 2200 1.1 3.0 15.0 0.26 1200 <0.2 6.7 4.1 3.3 SH-1/42-P 500 0.12 0.8 280 0.08 470 <0.2 1.5 2.4 1.6 

44
Appendix 13. Concentrations of elements extracted using 0.5 N HCl—Continued

Sample Li Mg Mn Mn# Mo Na Ni P Pb 

(ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) 

SH-1/1-P 3.8 2000 170 170 0.3 280 10 350 2.8 

SH-1/2-P 3.6 2500 220 220 <0.2 230 11 490 2.4 SH-1/3-P 5.0 3800 530 500 0.5 550 14 550 9.1 SH-1/4-P 6.1 3700 610 560 0.5 710 16 400 12 SH-1/5-P 0.6 410 25 23 <0.2 240 2.9 50 2.6 

SH-1/6-P 3.0 1800 670 640 <0.2 910 11 270 6.2 SH-1/7-P 3.3 2600 600 600 0.3 880 18 200 8.9 SH-1/8-P 0.3 210 12 11 <0.2 200 4.0 27 2.2 

SH-1/9-P 3.5 1700 760 700 0.4 930 12 180 8.7 

SH-1/10-P 0.7 400 21 20 <0.2 270 4.4 85 2.7 SH-1/11-P 1.6 840 1200 1200 <0.2 320 5.1 160 <1 SH-1/12-P 0.9 340 31 29 <0.2 300 4.3 120 2.2 SH-1/13-P 1.2 650 2300 2400 <0.2 540 5.1 180 <1 SH-1/14-P 1.3 560 930 890 <0.2 380 4.6 130 1.5 SH-1/15-P 2.5 1200 570 530 <0.2 600 8.0 340 <1 SH-1/16-P 1.8 1100 240 230 <0.2 730 6.2 230 3.0 SH-1/17-P 3.5 2300 340 330 <0.2 1100 15 260 8.3 

SH-1/18-P 0.7 340 250 240 <0.2 320 3.4 130 2.4 

SH-1/19-P 0.7 340 54 52 <0.2 420 2.4 190 1.4 SH-1/20-P 0.9 400 100 99 <0.2 220 3.7 180 2.0 SH-1/21-P 0.6 300 190 180 <0.2 220 2.8 140 2.3 SH-1/22-P 1.2 1200 3300 3200 0.7 750 6.1 280 <1 SH-1/23-P 1.9 810 320 320 <0.2 430 4.9 590 1.8 SH-1/24-P 0.6 300 75 68 <0.2 420 2.5 250 2.0 SH-1/25-P 0.9 460 380 360 <0.2 280 3.0 120 <1 SH-1/26-P 1.2 460 170 160 0.2 340 2.9 150 1.3 

45
Appendix 13. Concentrations of elements extracted using 0.5 N HCl—Continued

Sample Li Mg Mn Mn# Mo Na Ni P Pb 

(ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) 

SH-1/27-P 0.5 310 220 210 <0.2 440 2.6 110 1.4 

SH-1/28-P 0.9 520 150 150 <0.2 540 4.1 220 1.8 

SH-1/29-P 2.5 1500 830 780 0.3 660 8.2 510 1.5 

SH-1/30-P 0.9 450 320 300 <0.2 450 3.4 240 <1 

SH-1/31-P 1.1 630 420 410 <0.2 660 3.4 180 <1 

SH-1/32-P 0.9 530 180 170 <0.2 600 2.8 230 <1 

SH-1/33-P 5.0 3400 530 500 0.5 1500 17 310 20 SH-1/34-P 3.9 2400 460 430 <0.2 510 12 240 8.7 SH-1/35-P 0.7 590 220 210 <0.2 350 2.3 190 2.9 

SH-1/36-P 7.8 4000 360 360 <0.2 430 21 190 11 SH-1/37-P 1.3 600 130 120 <0.2 330 4.0 350 1.5 

SH-1/38-P 1.0 480 240 230 <0.2 240 3.2 130 <1 

SH-1/39-P 1.0 530 210 200 <0.2 410 3.5 180 <1 

SH-1/40-P 0.6 320 82 80 <0.2 250 2.2 120 <1 

SH-1/41-P 3.6 1900 290 280 0.3 160 11 270 4.2 SH-1/42-P 0.7 350 29 27 <0.2 330 2.5 150 1.5 

46
Appendix 13. Concentrations of elements extracted using 0.5 N HCl—Continued

Sample Sr Ti V Zn 

(ppm) (ppm) (ppm) (ppm) 

SH-1/1-P 5.4 210 8.2 17 

SH-1/2- P 5.6 270 8.3 17 SH-1/3- P 11 230 15 25 SH-1/4- P 14 170 14 27 SH-1/5- P 1.8 25 4.9 4.6 SH-1/6- P 12 51 13 22 SH-1/7- P 21 22 17 30 SH-1/8- P 2.1 3 0.9 4.0 SH-1/9- P 14 40 8.0 28 

SH-1/10-P 2.6 18 1.4 6.6 SH-1/11-P 2.9 77 12 40 SH-1/12-P 2.0 36 1.7 6.4 SH-1/13-P 4.4 <0.5 7.0 54 SH-1/14-P 2.6 56 7.2 12 SH-1/15-P 4.6 72 8.4 20 SH-1/16-P 5.4 44 4.5 35 SH-1/17-P 11 78 8.8 28 SH-1/18-P 3.7 17 2.7 8.5 SH-1/19-P 3.3 21 1.8 5.2 SH-1/20-P 2.0 56 2.4 8.0 SH-1/21-P 1.7 25 1.7 7.1 SH-1/22-P 8.0 <0.5 6.8 25 SH-1/23-P 6.2 100 7.1 15 SH-1/24-P 3.6 20 1.7 4.4 SH-1/25-P 1.9 72 4.8 6.5 SH-1/26-P 2.5 50 4.0 7.9 

47
Appendix 13. Concentrations of elements extracted using 0.5 N HCl—Continued

Sample Sr Ti V Zn 

(ppm) (ppm) (ppm) (ppm) 

SH-1/27-P 5.2 16 2.3 4.2 

SH-1/28-P 8.1 33 4.0 7.5 SH-1/29-P 5.4 150 13 15 SH-1/30-P 2.5 50 5.4 6.2 SH-1/31-P 8.8 <0.5 4.2 44 SH-1/32-P 2.9 53 3.4 5.5 SH-1/33-P 21 <0.5 7.5 32 SH-1/34-P 13 11 5.9 22 SH-1/35-P 9.5 13 2.5 13 SH-1/36-P 9.3 270 16 38 SH-1/37-P 11 63 3.1 18 SH-1/38-P 7.5 48 2.5 16 SH-1/39-P 10 53 2.7 18 SH-1/40-P 8.0 18 1.3 9.3 SH-1/41-P 7.0 130 5.5 23 SH-1/42-P 9.9 22 1.1 13 

48
Appendix 14. Concentrations of iron, manganese, aluminum and arsenic extracted from preserved 

sediment samples from the GSB borehole Srirampur, Kachua using the reductive extract solution of 

Ti(III)-EDTA.

[iron, manganese, and aluminum determined by atomic absorption spectrophotometry; arsenic determined by hydride 

generation atomic fluorescence spectrometry] 

Sample Fe Mn Al As 

(ppm) (ppm) (ppm) (ppm) 

SH-1/1-P 1900 14 100 0.6 

SH-1/2-P 1500 10 60 0.6 

SH-1/3-P 2300 17 170 1.3 

SH-1/4-P 2900 23 240 1.8 

SH-1/5-P 630 2 15 0.6 

SH-1/6-P 1100 14 260 0.6 

SH-1/7-P 2400 32 nd 0.4 

SH-1/8-P 380 2 58 <0.1 

SH-1/9-P 1300 22 460 0.3 

SH-1/10-P 490 4 83 0.3 

SH-1/11-P 670 19 35 0.3 

SH-1/12-P 340 5 66 0.3 

SH-1/13-P 1000 45 92 0.2 

SH-1/14-P 310 7 35 <0.1 

SH-1/15-P 340 5 54 0.2 

SH-1/16-P 830 76 120 0.3 

SH-1/17-P 1200 90 290 1.3 

SH-1/18-P 300 3 35 0.1 

SH-1/19-P 440 5 48 0.3 

SH-1/20-P 180 1 35 <0.1 

SH-1/21-P 230 2 36 <0.1 

SH-1/22-P 1400 43 73 0.2 

SH-1/23-P 520 7 93 <0.1 

SH-1/24-P 290 3 67 0.1 

SH-1/25-P 250 4 17 <0.1 

SH-1/26-P 220 1 48 0.1 

SH-1/27-P 260 3 17 0.1 

SH-1/28-P 410 5 120 0.1 

SH-1/29-P 580 6 85 0.5 

SH-1/30-P 160 1 49 <0.1 

SH-1/31-P 1000 8 1300 0.3 

SH-1/32-P 130 1 69 0.2 

SH-1/33-P 2200 35 650 0.4 

SH-1/34-P 1200 17 410 0.5 

SH-1/35-P 710 3 87 0.2 

SH-1/36-P 1800 17 100 <0.1 

SH-1/37-P 780 5 50 0.2 

SH-1/38-P 400 2 55 0.1 

SH-1/39-P 680 4 51 0.1 

SH-1/40-P 280 1 17 <0.1 

SH-1/41-P 660 6 150 0.5 

SH-1/42-P 400 2 35 0.1 

49
Appendix 15. Concentration of arsenic extracted from preserved sediment samples from the GSB 

borehole, Srirampur, Kachua, using an oxidative extract solution of H2O2 and HCl. 

[arsenic determined by hydride generation atomic fluorescence spectrometry]

Sample As 

(ppm) 

SH-1/1-P 1.2 

SH-1/2-P 1.3 

SH-1/3-P 3.2 

SH-1/4-P 5.0 

SH-1/5-P 0.3 

SH-1/6-P 1.8 

SH-1/7-P 1.2 

SH-1/8-P 0.1 

SH-1/9-P 1.0 

SH-1/10-P 0.5 

SH-1/11-P 1.0 

SH-1/12-P 1.3 

SH-1/13-P 2.2 

SH-1/14-P 1.6 

SH-1/15-P 0.7 

SH-1/16-P 1.9 

SH-1/17-P 6.2 

SH-1/18-P 0.7 

SH-1/19-P 0.4 

SH-1/20-P 1.1 

SH-1/21-P 0.3 

SH-1/22-P 1.2 

SH-1/23-P 0.5 

SH-1/24-P 0.4 

SH-1/25-P 0.4 

SH-1/26-P 1.5 

SH-1/27-P 0.8 

SH-1/28-P 0.4 

SH-1/29-P 3.1 

SH-1/30-P 0.4 

SH-1/31-P 1.7 

SH-1/32-P 0.5 

SH-1/33-P 4.1 

SH-1/34-P 5.2 

SH-1/35-P 0.2 

SH-1/36-P 6.0 

SH-1/37-P 0.7 

SH-1/38-P 1.1 

SH-1/39-P 0.6 

SH-1/40-P 0.4 

SH-1/41-P 4.6 

SH-1/42-P 0.2 

50
Appendix 16. Concentration of acid-volatile sulfide (AVS), pyritic sulfur (DI), and acid-soluble 

sulfate (SO4) in selected preserved sediment samples from the GSB borehole, Srirampur, Kachua. 

[nd, not determined] 

Sample Sulfide -AVS 

(ppm) 

Acid-soluble-SO4 

(ppm) 

Sulfide -DI 

(ppm) 

SH-1/1-P 65 10 70 

SH-1/2-P 60 10 220 

SH-1/3-P 50 <10 310 

SH-1/5-P 30 <10 120 

SH-1/7-P 30 <10 20 

SH-1/9-P 30 10 110 

SH-1/12-P 280 80 1090 

SH-1/14-P nd nd 38 

SH-1/16-P 20 <10 520 

SH-1/18-P 20 <10 330 

SH-1/20-P 10 <10 200 

SH-1/23-P 96 nd 128 

SH-1/28-P 10 40 220 

SH-1/33-P 20 110 590 

SH-1/34-P 120 15 90 

SH-1/36-P 40 70 1170 

SH-1/41-P 80 <10 1540 

51