Exposure of sulfidic sediments to atmospheric conditions can under various environmental and anthropogenic influences. The oxidation of sulfides results in the production of acidity, dissolution of aluminosilicates and pedogenci development. This process has acid sulfate landscapes throughout the world identified as major emitters of elevated concentrations of chemical metals. This emission of acidity and metals alters the bioaccessibility and subsequently has a deleterious impact on the surrounding biologic environment. Despite this, the examination of the biologic impact in these landscapes has received only minimal attention. Passive and dynamic hydrogel techniques were used to measure the bioaccessibility of metals in sediments and waters. The technique involved the construction of a restricted pore-size thin-film hydrogel that allowed for the diffusion of the bioaccessible fraction, composed of the free-ion and easily dissociable metal-complexes. The dynamic hydrogel technique contained a resin sink, which allowed for a time-integrated flux concentration to be calculated. The dynamic hydrogel technique was trialled and found to correlate with the pygmy mussel (Xenostrobus securis) aluminium uptake for short exposure periods (24 hours).The dynamic hydrogel metal concentration was also found to correlate to indpendantly measured pore water and simultaneously extracted metal (SEM) concentrations. The hydrogel techniqe was further applied to investigate the sediment-water interface in drained and non-drained acid suflate landscapes. The studied Australian and Finnish acid sulfate landscapes showed contrasting relationships between the acid volatile sulfides (AVS) and SEM fractions. In the Australian sediments, a conversion of AVS-S to FeS2-S occurs with depth driven by a polysulfide pathway, whilst the Finnish sediments displayed a persistence of AVS-S with depth with limited conversion to FeS2-S. Distinct variations exist at the sediment-water interface of the two contrasting landscapes, with AVS-S to FeS2-S ratios of 2.5 for the Australian and 0.2 in the Finnish sediments. The sediment geochemistry regulated metal mobility. A two-dimensional passive and dynamic hydrogel approach illustrated microniches and supply zones of aluminium iron, manganese and zinc at varying depths near the sediment-water interface. The measurement of bioaccessibility using an in situ technique in acid sulfate landscapes is a first for both Australia and Finland, and this research provides an important avenue for future water and sediment quality monitoring.

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "Inland acidic sulfate soils under fresh water conditions where contemporary clearning of native vegetation has caused erosion, rising of local water tables and excess discharge of saline-sulfatic groundwater. A new systematic and interactive web-based approach was used to improve acquisition, collation, integration and communication of diverse soil-regolith data ... Successful application of the interactive web-based data site, as part of this study, resulted in its uptake as a standard tool for coordinating and reporting on a number of current and future national and international soil-regolith studies." -- from Abstract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289208 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Enviromental Sciences, 2007

Title page, contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / "Inland acidic sulfate soils under fresh water conditions where contemporary clearning of native vegetation has caused erosion, rising of local water tables and excess discharge of saline-sulfatic groundwater. A new systematic and interactive web-based approach was used to improve acquisition, collation, integration and communication of diverse soil-regolith data ... Successful application of the interactive web-based data site, as part of this study, resulted in its uptake as a standard tool for coordinating and reporting on a number of current and future national and international soil-regolith studies." -- from Abstract. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1289208 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Enviromental Sciences, 2007

Brackish water aquaculture is one of the largest coastal industries in Indonesia. This farming system involves the construction of ponds m coastal sediments. Many ponds in Indonesia have been abandoned due to past development of ponds in acid 8ulfate soils (ASS); these soils produce sulfuric acid through the oxidation of pyrite du ring and after the sediments have been excavated. The soils also contain elevated concentrations of metal such as iron and aluminium which are harmful to farmed fish and shrimp. Acidification of pond soil causes recurrent fish and shrimp mortalities, poor growth rate in fish and shrimp, soft shell syndrome in shrimp and low plankton densities, Pond maintenance costs in ASS are also significantly higher than non-ASS ponds. There are over 6.7 million ha of ASS In Indonesia of which 35% has been developed for brackish water aquaculture. This study developed and trialled methods of soil remediation to restore abandoned ASS-affected ponds. The main objective was to develop methods at remediation that were scientifically sound but also practical and inexpensive for farmers. The research involved characterising, in detail, the chemical and physical properties of ponds soil followed by laboratory-based experiments to improve soil properties. The results of laboratory trials were the basis for large-scale field experiments to test soil remediation strategies. The study showed that pond bottoms could be improved by forced oxidation, flooding and water exchange followed by Iiming and fertilising. Up to 500% increases in productivity were achieved by this method and soils conditions Improved significantly. A further twofold productivity increase was achieved by an integrated liming method in which lime is added to rebuilt or new dykes in layers. A juvenile shrimp production system was developed for ponds that were too severely degraded or costly to remediate. The research developed methods of preventing metal toxicity in Juvenile shrimp. The study showed that aquaculture ponds built in ASS could be remediated and returned to viable production systems. Importantly, the study has developed a more detailed understanding of chemical properties In ASS-affected ponds.

Acid Sulphate Soils (ASS) often cause acidic pollution in canal water, which negatively impacts on water quality, biodiversity and the livelihood of farmers and fishermen, especially the landless poor. The problem is particularly acute in the coastal zones, where people already suffer from the consequences of salinity intrusion. Reducing acidic pollution is important for improving agricultural and aqua-cultural production and also the living conditions of people living in coastal zones with ASS. This study aims at developing an analytical tool that can simulate the propagation of acidic pollution and that would allow planers and managers to develop water management options and other resource management measures to reduce acidic pollution in the canal network of a coastal zone. / This study utilizes a systems approach, with a series of field, laboratory studies, in combination with statistical and GIS-based analyses and simulation modelling. Field and laboratory studies were carried out during 2001 - 2006 in Ca Mau peninsula, Mekong Delta, Vietnam, to fill in knowledge gaps on the source and amount of acidic loads from soil to the water surroundings, their interaction with saline water and their propagation in the canal network. Knowledge generated from this study was used in developing and validating a model to simulate the propagation of acidity in the tidal canal network with brackish water. / Measured data showed that the acidic pollution in the canal network varies seasonally. The pH of the canal water was lowest (3 – 4.5) at the beginning of the rainy season and highest (7 – 7.5) at the end of the rainy season and during the dry season. The reduced dredging activities in year 2005 and 2006 may explain why the acidic pollution decreased in 2005 – 2006 compared with 2001 –2004. The most serious acidic pollution occurs when the two following conditions are present simultaneously: (i) The existence of newly dredged canals (and hence the deposition of the excavated spoils on the canal embankment) in areas with ASS (especially with a severe ASS); and (ii) little or a lack of water exchange from tidal flows. Field experiments showed that ASS embankments within 2-3 years after dredging represent a high acidity hazard because they can release into the canal a total acidity, mainly from runoff and seepage water, of up to 2.7 mol H+day-1 per meter length of canal embankment. Functional relationships were established allowing quantification of the daily acid load transferred from fields and canal embankments to the canal network. / A laboratory titration experiment showed that saline water could buffer the effects of acidic pollution in the canal water. A new ACIDITY module was developed and was coupled to an existing hydraulics and salinity model (the Vietnam River Systems And Plains - VRSAP). The model was calibrated with measured data from 2003 and validated with data from 2005. The Model is the first of its kind able to simulate the temporal and spatial dynamics of changes of pH (as an indicator of acidity) at a regional scale, together with salinity and water flow characteristics in a tidal canal network with brackish water. The Model can be used to investigate the effects of different scenarios of water and other resource management options on the extent of acidic pollution in a coastal area. Analysis of simulation runs for various scenarios indicate that opening the two main sluices along the East Sea at high tide in one day every week in May and June for saline water intake, combined with widening the canals that connect these sluices to the West Sea can eliminate the acidity problem in the study area. Large scale dredging of canals of ASS in fresh water zone should be avoided as it can create severe acidic pollution of the canal water.

Bibliography: leaves 223-266. / xix, 306 leaves : ill. (some col.), maps ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Experiments were conducted, based on the hypothesis that organic amendments held some promise for improvements of physical properties of acid-sulphate mine tailings and for the resulting acid drainage. Concerns the ability of various organic and inorganic materials to ameliorate materials from acid-sulphate mine tailings as collected at Brukunga, South Australia / Thesis (Ph.D.)--University of Adelaide, Depts. of Geology and Geophysics and Geographical & Environmental Studies, 2000?

Abstract This thesis examines temporal and spatial variations in the status of different rivers and streams of western Finland in terms of acidity and sources of acid load derived from the catchment area. It also examines the monitoring of acid runoff water derived from maintenance drainage in peatland forestry and suggests potential mitigation methods. A total of 17 river basins of different sizes in western Finland were selected for study, including rivers affected by both drainage of agricultural AS soils and forested peatlands. Old data from 1911–1931 were available, but most data were from the 1960s onwards and were taken from the HERTTA database. During 2009–2011, pH and conductivity measurements and water sampling were conducted. Biological monitoring for ecological classification was conducted in the Sanginjoki river system during 2008 and 2009. Three peatland forestry sites were selected to study acid leaching via pH and EC measurements and water sampling. Fluctuations in groundwater level in different drainage conditions were simulated and acid leaching was investigated in laboratory experiments in order to replicate a situation where the groundwater level drops and allows oxidation of sulphidic materials. It was found that river pH decreased and metal concentrations increased with runoff. The highest acidity observed coincided with periods of intense drainage in the 1970s and after dry summers in the past decade. Together with pH, electric conductivity and sulphate in river water were identified as suitable indicators of AS soils in a catchment, because they directly respond to acid leaching derived from AS soils. Acidity derived from organic acids was clearly observed in catchments dominated by forested peatlands and wetlands. Temporal and spatial variations in ecological status were observed, but monitoring at whole-catchment scale and during consecutive years is needed to increase the reliability of the results. Simulations on the potential effects of maintenance drainage in peatland forestry on runoff water quality showed a clear risk of oxidation of sulphidic materials during dry summers. This can be prevented mainly by avoiding too deep drainage. Knowledge of the hydrochemical impacts of acidic load derived from AS soils and drained peatlands is necessary for land use planning and sustainable water management of river basins affected by these soils. / Tiivistelmä Tutkimuksessa tarkastellaan Suomen länsirannikon happamuudesta kärsivien jokivesistöjen tilan ajallista ja paikallista vaihtelua. Tutkimuskohteena on sekä happamien sulfaattimaiden että ojitettujen turvemaiden jokivesistöjä. Tutkimuksessa tarkastellaan myös sulfidipitoisilta metsäojitetuilta turvemailta valuvaa happamuutta sekä ehdotetaan tällaisille kohteille soveltuvia keinoja huuhtouman ehkäisemiseksi. Tutkimukseen valittiin 17 erikokoista jokivesistöä, joiden valuma-alueella on sekä happamia sulfaattimaita että metsäojitettuja turvemaita. Varhaisin väitöskirjaan sisällytetty aineisto on vuosilta 1911–1931. HERTTA-tietokannasta poimittiin aineistoa happamuusmuuttujista 1960-luvulta alkaen. Vuosina 2009–2011 suoritettiin pH- ja sähkönjohtavuusmittauksia sekä otettiin vesinäytteitä Siika- ja Pyhäjoen valuma-alueen joista sekä näiden välissä sijaitsevien pienempien valuma-alueiden joista. Ekologisen tilan selvittämiseksi otettiin biologiset näytteet Sanginjoen valuma-alueen joista ja puroista vuosien 2008 ja 2009 aikana. Kunnostusojituskohteilla seurattiin pH:n ja sähkönjohtavuuden muutoksia kokoojaojissa sekä otettiin vesinäytteitä. Pohjaveden pinnan vaihtelua selvitettiin sekä kenttämittauksilla että mallinnuksen avulla. Laboratoriokokeen avulla selvitettiin sulfidien hapettumista. Metallipitoisuudet nousivat ja pH laski valumien kasvaessa. 1970-luvulla toteutetut salaojitukset heijastuivat jokien happamuuden kasvuna. Myös viime vuosikymmenen kuivat kesät näkyivät veden happamuuden lisääntymisenä syksyn ylivirtaamatilanteissa. Veden pH, sähkönjohtavuus sekä sulfaatti ilmensivät happamien sulfaattimaiden esiintymistä valuma-alueella. Orgaanisista hapoista peräisin olevaa happamuutta havaittiin valuma-alueilla, joilla on runsaasti ojitettuja turvemaita. Ekologisen tilan ajallisen ja paikallisen vaihtelun vuoksi seurantaa tulisi toteuttaa peräkkäisinä vuosina sisällyttäen tarkasteluun valuma-alueen eri jokia ja puroja. Kunnostusojitukset voivat aiheuttaa happamuutta, jos ojitus ulottuu sulfidikerrokseen. Riski on olemassa poikkeuksellisen kuivina kesinä. Sulfidien hapettumista voidaan ehkäistä välttämällä liian syvien ojien kaivamista. Maatalouskäytössä olevilta happamilta sulfaattimailta ja ojitetuilta turvemailta peräisin olevan huuhtouman vaikutukset tulee tuntea, jotta valuma-alueiden maankäyttöä ja vesiensuojelua voidaan toteuttaa tehokkaasti.

Increasing attention is being given to acid sulphate soils wherever they occur. The problems that leaching sulphate soils gives with significant lowerings of pH and mobilization of heavy metals influence large spectra of our society from fisheries to agriculture to construction. Mapping these soils is consequently of great importance and the methods of doing this is very much lacking in function and precision. This study was therefore carried out to investigate whether conductivity in running water can be used as a simple instrument to identify acid sulphate soils in the catchment. 31 coastal streams in the county of Västerbotten were analyzed for different catchment properties such as occurence of marine sediments and basic water chemistry including conductivity and sulphate. Sulphate proved to be the dominant factor controling conductivity in most streams, constituting up to 90 % of the anions. The results also showed that the concentrations of sulphate correlated to 67 % with marine sediments in the catchment. Where conductivity values exceeded 90 µS/cm the influence of acid sulphate soils could be determined for certain. The major conclusion drawn from this study is that high conductivity values serves as a reliable indicator of leaching acid sulphate soils whereas lower values can not exclude them. / flisik

The escalating pollution of the environment has been one of the greatest concerns of science in recent years. Industrial advances in agriculture, expansion of chemical industries and a general change in lifestyle all over the world has lead to release of a variety of pollutants into the environment, thus contaminating the atmosphere, water bodies and many soil environments. In general, other than some natural processes, soils are increasingly being contaminated by anthropogenic sources such as leakages from waste containment facilities, accidental spills and industrial operations. Apart from affecting biotic components of the ecosystem, these pollutants greatly affect the performance, behavior and stability of the soil ecosystem, these pollutants greatly affect the performance, behavior and stability of the soil systems, thus causing severe damage to structures founded on them. The hydraulic and/or chemical alterations which allow these polluting substances to move within soil pores lead to physico-chemical decomposition processes, chemical alterations, leaching and ion exchange reactions. Such reactions could also result from natural processes such as weathering; but the effects caused by pollutants occur at faster rates. Soils are composed of clays, silts and sands. Due to charged nature of the particles and their large specific surface, engineering properties of clays are greatly affected by pollutants. The magnitude of these effects can vary significantly depending on the type of soil, the type and concentration of contaminant, duration of interaction and the environmental conditions. Hence, an understanding of contaminant-clay interactions is important for prevention of geotechnical features, if possible, or at least for planning of remedial measures. Understanding these effects and planning remedial measures requires measurement of the affected properties of polluted soils. This may involve the modification of standard test procedures or the development of new test procedures. The main types of contaminants include inorganic acids, alkalis, sulphates, organic contaminants, toxic or phytotoxic metals and combustible substances. All of these are widely used in industries. While the adverse effects of presence of sulphate in alkaline conditions is well known, little information is available on the effect of sulphate in natural soils under acidic environments. Sulphuric acid is widely employed in the production of fertilizers, pharmaceuticals, pigments, rayon, film, iron, steel, explosives, paper and paper industry. It is also used in cleaning, etching, petroleum refining, electroplating, metallurgy, and in lead-acid batteries. Due to its widespread but often improper usage and the difficulty in safe storage, sulphuric acid is often found as a contaminant in natural soils. Sulphuric acid is also generated in natural soils by oxidation by pyrites in the presence of atmospheric oxygen. Hence, an attempt has been made in this thesis to study the behavior of soils containing different clay minerals during acid-sulphate interaction. The effect of sulphate on soils containing calcite, whose presence is quite common, has also been studied. A review of literature suggests that most common geotechnical failures due to contamination occur due to significant changes on the volume change behavior. Also, it is known that severe changes that occur in soil properties can essentially be attributed to mineralogical changes that occur during interaction with pollutants. Therefore, volume change behavior of soil and detailed mineralogical changes and the consequent morphological changes that occur in soils with acid sulphate are studied.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.