Search

Aim: To explore clinical decision‐making by comparing the processes used by three groups of nurses in the emergency departments of three hospitals: in Norway, Finland and Ireland. Background: Clinical decision‐making in an emergency department environment is a complex process often occurring in times of crisis. It is an important aspect contributing to the quality of care. However, empirical research is limited regarding the decision‐making process in different nursing roles. Methods: In accordance with the consolidated criteria for reporting qualitative research, a qualitative and observational study was conducted to explore clinical decision‐making by comparing the processes used by three groups of nurses in the emergency departments of three hospitals: in Norway, Finland and Ireland. Six Registered Nurses, six Nurse Specialists and six Nurse Practitioners were observed. A total of 40 hours of observation was made at each setting according to a structured observation guideline, followed by clarifying questions. The data material was analysed by means of a qualitative manifest and latent content analysis. Results: Three themes arose: acting in accordance with routines, previous experience and intuition; considering patient experience; and facilitating new alternatives based on critical thinking. The Registered Nurses mainly used the first approach, the Nurse Specialists used the first and the second approaches, and the Nurse Practitioners used all three approaches. Conclusions: The results highlight the differences in decision‐making processes between these groups. Nurse Practitioners were the only group that facilitated and evaluated new alternatives using their clinical autonomy, such as stepping up and making independent and collaborative decision‐making. Implication: The results can be used in countries developing advanced practice nursing education and defining their scope of practice to inform stakeholders. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was to illuminate the meaning of being a nurse in the archipelago. Methodological Design and Justification: A phenomenological hermeneutical design was applied, as there is a need to understand the lifeworld and the meaning of being a nurse in the archipelago. Ethical Issues and Approval: Approval was granted by the Regional Ethical Committee and local management team. All participants provided consent to participate. Research Method: Individual interviews were conducted with 11 nurses (Registered Nurses or primary health nurses). The interviews were transcribed, and the text was analysed by means of phenomenological hermeneutical method. Results: The analyses ended in one main theme: Standing alone on the frontline, and three themes: 1. Combating sea, weather and the clock with the sub‐themes: Fighting to give care to patients despite harsh conditions and Fighting against time; 2. Standing firm but wavering with the sub‐themes: Embracing the unexpected and Calling out for support; and 3. Being a lifeline throughout the entire lifespan with the sub‐themes: Having responsibility for the islanders and Having an intertwined private and work life. Study Limitations: The interviews may be considered few, but the textual data were rich and assessed suitable for the analysis. The text may be interpreted differently, but we deemed our interpretation as more probable than others. Conclusion: Being a nurse in the archipelago means standing alone on the frontline. Nurses, other health professionals and managers need knowledge and insight about working alone and the moral responsibilities thereof. There is a need to support the nurses in their lonely work. Traditional means of consultations and support could preferably be supplemented by modern digital technology. [ABSTRACT FROM AUTHOR]

Established international soil classification systems have not properly accommodated acid sulfate soils (ASS) and soil materials in Finland and Sweden because: (1) in these soils some diagnostic ASS properties are too deep to meet the depth requirements, and (2) there is a lack of defined diagnostic soil classification criteria for acidic and potentially acidic soil materials that do not completely fulfill the diagnostic pH-criterion of pH < 4.0. In this paper, two new ASS materials are introduced with the prefix "para" for parasulfuric material (oxidized material) and parahypersulfidic material (reduced material). These materials have diagnostic pH-criteria of pH 4.0-4.5 and 3.0-3.5 (field-pH for parasulfuric material and incubation-pH for parahypersulfidic material) for mineral and organic soil materials (here defined as > 20% organic matter; peat and gyttja), respectively. The term "para-acid sulfate soil (para-ASS) material" is introduced for soil materials which may have a considerable environmental impact due to mobilization of acidity and dissolved metals. Because organic acids may lower pH to values below the established pH-value of < 4.0 for ASS materials, a pH of < 3.0 is used in the Finnish-Swedish ASS classification for organic soil materials. These changes and new additions to existing diagnostic ASS materials have consequently also led to a slight modification of the required field-pH values of the existing terms "hypersulfidic material" and "sulfuric material". The Finnish-Swedish ASS classification further includes a systematic way for classification of the entire soil profile and no depth requirements for diagnostic ASS materials are present; what matters is the current or potential environmental impact that the soil has or may have. It is proposed that the Finnish-Swedish ASS classification may serve as a framework for establishing a unified ASS classification globally and that the new diagnostic ASS materials are included in relevant international soil classification systems. [ABSTRACT FROM AUTHOR]

Acid sulfate soils (ASS) cause big problems worldwide due to their potential to form sulfuric acid during oxidation of sulfidic materials, resulting in very acid soil (pH <4.0). Impacts include acidification of soil and water, leaching of metals, decreased nutrient supply, deterioration of water fauna and flora, and corrosion of infrastructure. These soils also exhibit poor geotechnical properties. Finland has the largest occurrences of ASS in Europe, mainly along the coast of the Baltic Sea. The EU Water Framework Directive brought about wide co-operation to reduce the harmful impacts of ASS in Finland. One urgent step was to localize and characterize the occurrences of ASS The more than 10 year-long programme, led by the Geological Survey of Finland (GTK), started in 2009 and field work was completed in 2021. During the programme observations, measurements, sampling and analyses were made at 23 000 sites in an area of 5 010 000 ha. Traditionally ASS in Finland have been considered to comprise fine-grained sulfidic sediments and/or their oxidized layers, occurring on agricultural land along the coast below the highest shoreline of the Littorina Sea transgression. This study recognized and classified significant occurrences of other types of potentially harmful ASS materials: (1) coarse-grained ASS (sand), (2) organic ASS (peat) and (3) unsorted ASS (till material). The methods, definition and classification of Finnish ASS have been revised. We calculated the extent of ASS along the coast to be about 1000 000 ha corresponding to 21% of the area covered in the past by the Littorina Sea. and three to six times more than earlier estimates. In addition, some occurrences of ASS were recognized inland, mainly related to black shales and sulfidic ores. The mapping data can be accessed via the GTK map service (www.gtk.fi) providing information about the distribution and properties of ASS. [ABSTRACT FROM AUTHOR]

Nordic countries incarcerate offenders at much lower rates in comparison with incarceration rates in the United States, and reincarcerate fewer people per capita. Non-custodial alternatives to sanctions, including fines and community service, are used extensively in Finland to reduce negative effects of institutionalization and subsequent disadvantage caused by incarceration. The nature of drug-involved offenders within the Finnish system is reviewed in light of current research about the effectiveness of incarceration and deterrence-based approaches for drug offenders. Employing a 2014 sample from register data (consisting of official government records) of drug offenders in Finland with a 3-year recidivism period, this study utilizes a genetic matching procedure to compare offenders who received fines, conditional sentences (probation), or incarceration. While recognizing that numerous confounding variables affect incarceration, we compare a matched sample of drug offenders and the sanctions they have received from the Finland judicial system to determine whether offenders who initially receive a fine or a conditional sentence reenter the correctional system at different rates than those who are incarcerated. After matching, results found no significant differences between offenders receiving incarceration sentences or those who received noncustodial sentences (fine, or conditional sentence) for general and drug-related recidivism. These results are presented within the context of the Finnish corrections system in order to inform the criminal justice community about culture, incarceration, and process differences that could positively affect working with drug offenders in other localities. [ABSTRACT FROM AUTHOR]

To meet both current and future competence needs, improved and updated understanding of nurses' scope of practice when working in remote communities is needed. The aim was to describe and analyze the characteristics of nursing encounters in primary healthcare in remote areas. The setting for the study was an island community in Finland. Nurses' patient record documentation and self-reports on patient encounters were surveyed (n = 1062). Patients aged ≥65 years accounted for most encounters. Great variety in the encounters was seen, though some nursing tasks and patient conditions were overrepresented. For patient safety reasons, it is important to review how nurses maintain competence regarding those tasks and conditions encountered less often. Primary healthcare services should focus on the broader determinants of health. However, a more disease-oriented focus was seen. To ensure quality of care in primary healthcare in remote areas, there is a need for standardized routines for monitoring patients and documenting findings and performed interventions. [ABSTRACT FROM AUTHOR]

Background: Wide variation exists between the nursing competence requirements seen in the emergency care context and the subsequent design of nursing education programmes. Clarifying nursing roles and scope of practice may shed light on inconsistencies and encourage nurses to work to their full potential. Aim: Describe and clarify the overarching similarities and differences in registered nurses' and nurse specialists' scope of practice in emergency departments. Methods: A qualitative study performed in Finland and Norway, based on 11 interviews analysed by means of qualitative content analysis. Results: The results are presented in three main categories related to nurses' scope of practice: The nurses share the same role, Competence varies and Same accountability and responsibility, with potential for development of the specialist role. Discussion: Given the varying educational systems that currently exist, management teams face a more or less impossible task if attempting to standardise the scope of practice for different professional nurse groups. Still, nurse specialists possess competence that could be utilised to improve patient care and some specialisations seem more suitable for emergency care than others. Individual skills and qualifications should be recognised, which would enable nurses to work to their full potential. Conclusion and implications: No differences were seen between registered nurses' and nurse specialists' role, and professional accountability and responsibilities in the context studied here, although the level of nursing competence differed. Before and even after consensus on uniform competence standards for the different professional nurse groups is reached, management teams should invest in reviewing nurses' competence in relation to different expertise levels, and strategically recruit so that current health needs in the emergency departments can be met. [ABSTRACT FROM AUTHOR]

Acid sulfate (a.s.) soils have long been under investigation in Finland due to their negative impact on the environment. Earlier studies have mostly focused on fine-grained (< 63 μm) a.s. soil materials, but acidification caused by coarse-grained (≥ 63 μm) post-glacial a.s. soil materials has recently gotten more attention. Using a “let the soil speak for itself” incubation approach, we investigated six soil profiles consisting of mostly coarse-grained potential a.s. soil materials in a study area in western Finland. Although the sulfur concentrations and acidities in the reduced sulfidic coarse-grained parent materials were significantly lower (10–100 times) compared to fine-grained a.s. soil materials, the pH-values were similar and well below 4.0 for most samples after a 16-week (incubation) oxidation period. The coarse-grained materials also oxidized rapidly and displayed a fast drop in pH during the incubation. This was most likely due to a poor buffering capacity caused by the low specific surface and a quartz-feldspathic mineralogy, which is likely to cause a rapid leaching of acidity. No actual a.s. soil materials (pH < 4.0) were observed in the sampled soil profiles but are likely to occur within the study area; since all, besides one, of the sampled soil profiles contained potential a.s. soil materials. Acidity and metal problems were common in a nearby groundwater area utilized for drinking water, where Al, As, Cr, Co, Fe, Mn and Ni concentrations were elevated at least 10 times over background median values. In addition, oxidation of coarse-grained a.s. soil materials appear to have caused the pH to decrease as low as 3.4 in several sand pit lakes, formed by sand mining, where median levels of SO 4 , Al, Mn, Ni, Se and Zn were elevated > 10 times over background concentrations. We suggest that there is a strong link between the oxidation of coarse-grained post-glacial a.s. soil materials and a high acidity and elevated metal concentrations in groundwater and sand pit lakes. [ABSTRACT FROM AUTHOR]

Aim To explore the relationship between inner strength and health threats among community-dwelling older women. Background Inner strength is described as a resource that promotes experiences of health, despite adversities. Inner strength and its dimensions (i.e. connectedness, creativity, firmness and flexibility) can be assessed using the Inner Strength Scale ( ISS). Exploring attributes of weaker inner strength may yield valuable information about areas to focus on in enhancing a person's inner strength and may ultimately lead to the perception of better health. Design Cross-sectional questionnaire survey. Methods The study is based on responses from 1270 community-dwelling older women aged 65 years and older; these were collected in the year 2010 and describe the situation that still exists today for older women. The questionnaire included the ISS, background characteristics and explanatory variables known to be health threats in ageing. Data were analysed using descriptive and inferential statistics. Results Poorer mental health was related to weaker inner strength in total and in all the dimensions. Symptoms of depressive disorders and feeling lonely were related to three of the dimensions, except firmness and creativity respectively. Furthermore, poor physical health was associated with the dimensions firmness and flexibility. Other health threats were significantly related to only one of the dimensions, or not associated at all. Conclusion Mental ill health has overall the strongest association with weaker inner strength. Longitudinal studies are recommended to confirm the results. However, the ISS does not only estimate inner strength but can also be a tool for discovering where (i.e. dimension) interventions may be most profitable. [ABSTRACT FROM AUTHOR]

The aim of the present study was to explore health-related quality of life (HRQoL) and associated variables among all community-dwelling older women (≥65 years) (n = 2724) on Åland, a Finnish self-governing island community. A total of 1023 women participated (mean age 72.9 ± 6.8 years). Absence of depression, absence of diagnosed disease(s), having the opportunity to engage in meaningful leisure activities, and never or seldom feeling lonely explained, together with socioeconomic control variables (i.e. age, education and economic situation), 34.4% of the variation in physical health. Absence of depression, strong inner strength, and never or seldom feeling lonely explained, together with socio-economic control variables, 27.7% of the variation in mental health. HRQoL was rated as relatively good, although special attention should be paid to women aged 80þyears. To promote HRQoL, interventions aimed at preventing, detecting and treating depression should be prioritised. In addition, interventions aimed at reducing feelings of loneliness are also recommended in order to enhance overall HRQoL. [ABSTRACT FROM AUTHOR]

Objectives:The aim of this study was to explore if inner strength is independently associated with a reduced prevalence of depression after controlling for other known risk factors associated with depression. Methods:A population-based cross-sectional study was performed, where all women living in Åland, a Finnish self-govern island community in the Baltic Sea, aged 65 years or older were sent a questionnaire including the Geriatric Depression Scale and the Inner Strength Scale along with several other questions related to depression. Factors associated with depression were analyzed by means of multivariate logistic regression. Results:The results showed that 11.2% of the studied women (n= 1452) were depressed and that the prevalence increased with age and was as high as 20% in the oldest age group. Non-depressed women were more likely to never or seldom feel lonely, have a strong inner strength, take fewer prescription drugs, feeling needed, being able to engage in meaningful leisure activities, as well as cohabit. Conclusion:Our results showed an association between stronger inner strength and being non-depressed. This can be interpreted to mean that inner strength might have a protective effect against depression. These findings are interesting from a health-promotion perspective, yet to verify these results, further longitudinal studies are required. [ABSTRACT FROM PUBLISHER]

Abstract: The sulfur dynamics of boreal brackish-water sediments rich in metastable iron sulfide (average elemental composition of FeS1.1), which upon oxidation have a huge impact on stream-water chemistry, were studied. Two cores, extending from the upper oxidized layer (acid sulfate soil) into the underlying iron sulfide-bearing sediment (potential acid sulfate soil) were collected at a site close to the sea level and at another site about 40 m above the latter in a region of current isostatic land uplift (Finland). The data clearly show, in contrast to what is often argued, that these notorious acidic soils are formed not as a result of the natural uplift but because of extensive ditching of farmlands. Above the depth of artificial drainage, S and Ni are abundantly lost, while beneath that level pyrite is abundant and metastable iron sulfide is increasing with depth, and the Ni concentration is relatively stable. In the narrow zone between the reduced and oxidized layers, the processes are dynamic and result in preservation of elemental S at one of the locations. The sulfur isotopic composition for metastable iron sulfide and pyrite in the investigated acid sulfate soils were found to be distinctly bimodal and roughly corresponding to a similar distribution in stream-water sulfate earlier reported from the same region. This indicates that pyrite is the main source of sulfate and acidity in some affected drains, while in others it is metastable iron sulfide. [Copyright &y& Elsevier]

In Finland, acid sulfate (AS) soils are regarded as a serious environmental threat towards the Baltic Sea and watersheds situated in land areas that have emerged from the sea since the last glaciation due to glacial isostasy. The aim of this study is to compare the behavior of coarse-grained AS soil materials to the behavior of fine-grained AS soils and coarse-grained non-AS soils in order to (1) assess the potential environmental threat of coarse-grained AS soils and (2) to assess the need to distinguish coarse-grained AS soils from fine-grained AS soils in future risk assessment of AS soils. The hypotheses are that (1) a coarser grain size enhances the rate of oxidation and pH decrease due to larger inherited pore size, enabling better initial aeration and less efficient buffering processes due to lower particle surface areas and different mineralogy (more weathering resistant quartz and feldspars), and that (2) the leaching of acid generating materials and elements from coarse grained AS soils is significantly lower as compared to fine-grained AS soils but significantly higher as compared to coarse grained non-AS soils. The study used an incubation based "let the soil speak for itself"-approach, which means that parameters such as pH, acidity, amount of elements leached, and the electric conductivity of the leachates were measured on arrays of sample aliquots before, during, and after a 16 week incubation (oxidation) period. Even though the coarse-grained AS soil materials contained one order of magnitude less sulfide than the fine-grained AS soil materials, a S mass fraction as low as 0.01%, the pH dropped well below 4.0 upon oxidation, thus being classified as AS soils. The amount of acid generating materials and elements leached from coarse-grained AS soil materials were at least one order of magnitude less, as compared to the fine-grained AS soil materials, except for Fe, which leached in similar or greater quantities from coarse-grained AS soil materials. The differences in the leaching of acid generating materials and elements suggest it would be beneficial to divide coarse-grained and fine-grained AS soils into separate subgroups for risk management purposes. • Elements leach in greater amounts from fine-grained acid sulfate soils than coarse. • A sulfide mass fraction of 0.01% may lower the pH below 4.0 in coarse materials. • Iron is leached in large quantities from coarse-grained acid sulfate soil materials. • Leachate electric conductivity may be used to estimate leaching and acid generation. [ABSTRACT FROM AUTHOR]

Imbalanced datasets are one of the main challenges in digital soil mapping. For these datasets, machine learning techniques commonly overestimate the majority classes and underestimate the minority ones. In general, this generates maps with poor precision and unrealistic results. Considering these maps for land use decision-making can have dire consequences. This is the case of acid sulfate (AS) soils, a type of harmful soil that can generate serious environmental damage when drained in agricultural or forestry activities. Therefore, it is necessary to create high-precision maps to avoid environmental damage. Although most soil class datasets in nature are imbalanced, this problem has hardly been studied. One of the main objectives of this work is the evaluation of different techniques to address the problem of imbalanced datasets. The methods considered to balance the dataset are an undersampling technique, the addition of more samples, and the combination of both. For increasing the number of samples from the minority class, we develop a new technique by creating artificial samples from the quaternary geological map. The method used for the modeling is Random Forest, one of the best methods for the classification of AS soils. Balancing the dataset improves the performance of the model in all the studied cases, where the values of the metrics for both classes are above 80%. The consideration of artificial non-AS soil samples improves the prediction of the model for the AS soils. Furthermore, we create AS soil probability maps for the four balanced datasets and the imbalanced dataset. The modeled AS soil probability maps created from the balanced datasets have high precision. A detailed comparison between the maps is made. The predictions of some of these maps match between 75%–80% of the study area. In addition, the extent of the AS soils obtained in all the cases is compared with the extent of the AS soils in the conventionally produced occurrence map. The good results of this study confirm the importance of balancing the dataset to improve the prediction and classification of AS soils. • Different techniques were evaluated for addressing the problem of imbalanced datasets. • Balancing datasets improved prediction accuracy of acid sulfate soil mapping. • Highly accurate acid sulfate soil mapping from balanced datasets and random forest. • Detailed comparison of modeled acid sulfate soil probability maps in western Finland. [ABSTRACT FROM AUTHOR]

In Finland, nationwide mapping of acid sulfate soils (ASS) has been done since 2009 by the Geological Survey of Finland (GTK). In Sweden, regional ASS mapping has been done since 2012 by the Geological Survey of Sweden (SGU). GTK and SGU have collaborated in two EU-funded projects in order to unify the methods for classification, characterization and mapping of ASS. The definitions, diagnostic criteria and terminology for ASS set by the International Acid Sulfate Soils Working Group in 2008 have been adopted for ASS in Finland and Sweden, however with some minor modifications for characterization of hypersulfidic materials in organic soil materials and introduction of new diagnostic criteria and terminology for soil materials that are close to being classified as ASS materials but which are not completely fulfilling the diagnostic criteria. When applicable, the ASS materials are also classified according to the most recent version of the World Reference Base for Soil Resources (WRB).ASS are in Finland and Sweden defined as soils, sediments (incl. glacial till) and organic materials (e.g. peat) containing hypersulfidic materials which upon natural oxidation in the field or during incubation in the laboratory form sulfuric acid that lowers soil-pH to <4.0 for mineral soil materials or <3.0 for organic soil materials. Because organic acids can lower soil-pH to around 3.5–4.0, we have chosen to use a lower pH-limit for organic soil materials in order to distinguish between acidity formed from sulfide oxidation and that originating from organic acids.An important issue to consider during classification of ASS is how to handle soil materials where the pH due to sulfide oxidation drops considerably (e.g. ≥1 pH unit) during incubation, or during field conditions, to values close to, but not triggering, the diagnostic criteria for classification as ASS. With current international classification systems such soils are considered non-ASS even though the possible environmental impact, e.g. release of acidity and metals due to sulfide oxidation, can potentially be very high. Mapping of ASS in Finland and Sweden have shown that areas with this type of soils can be quite large. We have therefore introduced the prefix "pseudo" (i.e. pseudo acid sulfate soil), which here can be described as "close to" or "almost", in order to describe a soil not fulfilling the ASS criteria but which may have a considerable environmental impact due to sulfide oxidation.In order to enable classification of pseudo ASS, we have also introduced the terms "pseudo sulfuric material" and "pseudo hypersulfidic material". Pseudo sulfuric material is used only for mineral soil materials and is characterized by a pH of 4.0–4.5 in the oxidised horizon. This material is important in Finnish and Swedish soils as they often contain soluble aluminium that leach out from the soil, occasionally causing severe problems for fish in recipient waters, at pH-levels around 4.5. Pseudo hypersulfidic materials display a pH-drop of ≥1 unit to values between 4.0–4.5 and 3.0–3.5, in mineral and organic soil materials, respectively. [ABSTRACT FROM AUTHOR]

Acid sulfate soils (ASS) are in Finland defined as soils, sediments (including glacial till),organic material (e.g. peat) containing hypersulfidic materials which upon oxidation, eithernaturally or during incubation in the laboratory, form sulfuric acid that significantly lowerssoil-pH to &#x003C;4 for mineral soil materials and &#x003C;3 for organic soil materials. In Finland, ASSare disturbed in agriculture, forestry, peat production, dredging and infrastructuredevelopments. The sulfidic sediments responsible for ASS formation have been developing after thelatest glaciation in parts of the Baltic Sea beginning during the Littorina Sea (c. 8000–3000years ago) and today continuing in shallow coastal waters. Post-glacial isostaticuplift has brought these sediments above sea level and they are now consequentlymostly found in coastal areas. The most common type of ASS in Finland consistlargely of fine-grained (clay and silt) and often gyttja-containing soil materials thatgenerally have been deposited in estuary systems where the input of organic matter ishigh and the conditions for sulfide formation are favourable. In these soils, thereduced hypersulfidic material is often dark coloured indicating the presence of ironmonosulfides. The problems with leaching of acidity and metals into recipient waters related toASS have been known for centuries, but not until 2009 did systematic mappingand characterization commence on the responsibility of the Geological Survey ofFinland (GTK). At the observation points, soil probing and sampling down to 2–3m is done and observations of sediment texture and structure, pH and oxidationdepth are made. Samples are collected for analyses of incubation-pH, trace- andmajor elements (aqua regia dissolution and ICP-OES), loss on ignition and grainsize. Fine-grained ASS contain a relatively high concentration of sulfur (median c. 0.5%) and alarge pool of easily mobilised metals. During the mapping process it has become evident thatthere are also coarse-grained soils (fine sand and sand), constituting of glaciogenic and/orre-deposited glaciogenic material, which have low concentrations of sulfur (0.01–0.1%)metals and organic matter and that are strongly acidified to pH well below 4 when oxidised inthe laboratory. Due to the lower concentrations of acidity and metals, the negativeenvironmental impact of these coarse-grained ASS is much less or more short-lived than thatof fine-grained ASS. However, because of the poor buffering capacity of these soils, even alow sulfur content can induce leaching of acidity strong enough to cause fish killsin recipient streams. Also sulfidic till and peat have been encountered, often inassociation with black schists, and reportedly have had a negative impact on theenvironment. By the end of 2018, about 82% of the total potential 5 million hectares has been mapped.To date, &#x003E;21 000 observation points (observation density c. 0.5/km2) and &#x003E;10 000 analyseshave been made. Once the mapping is finished, the area of ASS is very likely to exceed thatof earlier estimations of 336 000 ha. The results from the mapping (incl. probability maps,site descriptions and analyses) are made public at http://gtkdata.gtk.fi/Hasu/index.html. [ABSTRACT FROM AUTHOR]

In Finland, acid sulfate (AS) soils are regarded as a serious environmental threat towards the Baltic Sea and watersheds situated in land areas which have emerged from the sea since the last glaciation due to glacial isostasy. Because of this, a national mapping and data collection program of Finnish AS soils started in 2009. The mapping raised many questions regarding characterization and risk assessment of boreal AS soils, in particular coarse-grained (median grain size ≥ 63 μm) AS soils. In some cases, coarse-grained AS soils may cause severe acidity and metal problems even though their sulfide and metal content are magnitudes lower compared to fine-grained (median grain size < 63 μm) AS soils. The aim of this study is to assess the potential environmental threat of coarse-grained AS soils and criteria to be used in future risk assessment.The hypotheses are that (1) some coarse-grained AS soils leach significantly less metals and acidity than fine-grained AS soils, thus, posing a smaller threat to the environment; and (2) coarse-grained AS soils should be considered as a subgroup separate from fine-grained AS soils. Research and sample materials used for this study is data obtained from the national AS soil mapping, additional samples collected from 12 soil profiles, and 3 sulfidic aquatic sediments. The study used an incubation based "let the soil speak for itself"-approach, which means that parameters such as pH and acidity were measured on arrays of sample aliquots before, during, and after a 16-week incubation (oxidation) period. In addition, we utilized a modified version of the standard leaching method EN 12457-2:2002 to quantify the amount of acidity and metals released from the soil materials before, during, and after incubation. General properties such as grain-size and bulk chemistry (aqua regia leachable elements) were determined as well.Preliminary results show that some of the studied coarse-grained AS soil materials released at least one magnitude less metals and acidity, as compared to the fine-grained AS soil materials. However, one exception was iron, which was leached in greater quantities from coarse-grained AS soil materials than from fine-grained. The results also indicate that the leachate electric conductivity (EC), measured in the leachate obtained at the end of the incubation period, may be used to assess the amount of metals liberated during oxidation; if the initial EC (measured in the leachate obtained from a sample aliquot at the start of the incubation period) is known. For reduced parent materials, total sulfur (measured as aqua regia leachable sulfur) might be sufficient for a crude assessment of the amount of metals and acidity potentially released if the materials were to be oxidized. The preliminary results create an incentive to divide coarse-grained AS soils into subgroups based on their acidity and metal leaching potential; as some coarse-grained AS soil material's leaching capabilities are indeed equivalent to those of "traditional" fine-grained AS soils, and some coarse-grained AS soil materials do not seem to leach more than non-AS soil materials. [ABSTRACT FROM AUTHOR]

Acid sulfate soils can cause severe environmental harm due to a low pH and mobilization of harmful elements. Acid sulfate soil material is formed when oxidation of sulfide minerals causes a drop in pH to <4.0 for mineral oil materials and <3.0 for organic soil materials or when the soil materials contain enough sulfide to potentially do so. Two dredged, acid sulfate soil materials from Finland were used in this laboratory study. Chemical analyses were performed to determine the pre-incubation characteristics of both fresh dredged sediment samples and oxidized samples after 23 weeks of incubation. Total element concentrations were determined after digestion in aqua regia by ICP-MS or ICP-OES. The leachable concentration of elements was determined by using the two-stage shaking test (method SFS-EN 12457-3). The leaching of harmful elements (Cd, Co, Ni, Mn, and Zn) was high in the acidified dredged spoil samples. Also, the leaching of S was high. The soluble concentration was dependent on total concentration, pH, and the mobility of the elements. During a 23-week oxidation period, the impact of various amounts of industrial side streams (alkaline ashes, industrial lime residues) as neutralizing agents on the acid-generating dredged sediments was investigated in the laboratory. Calcite was used as a reference material. pH measurements were carried out during the incubation period. The leaching of elements was determined with a modified method based on the SFS-EN 12457-2 standard before and after oxidation. The untreated dredged spoils and the samples treated with too low amounts of neutralizing agents, acidified to pH < 4 during the oxidation period. Thus, harmful elements were leached out. However, the 100 % theoretical calculated neutralization need was suitable to prevent acidification and thus the leaching of harmful substances from the neutralized acid-generating dredged spoils. However, the leaching of Mo increased at neutral pH values. The results showed that industrial side streams can be applicable for the neutralization of acid sulfate soil materials. However, the legislation must also be considered. • Two different dredged spoils were studied, both were characterized as acid sulfate soil materials. • Harmful elements (e.g., Cd, Co, Mn, Ni, and Zn) were leached out during the incubation period. • Neutralizing with industrial side streams prevented acidification and thus leaching of metals. • Legislation limits the use of side streams and the beneficial use of soils. [ABSTRACT FROM AUTHOR]

• We evaluate different machine learning techniques for acid sulfate soil mapping. • Acid sulfate soil maps in southeastern Finland created from machine learning models. • Accurate acid sulfate soil mapping with gradient boosting and random forest. • A detailed comparison of the conventional and modeled acid sulfate soil maps. Acid sulfate soils are one of the most environmentally harmful soils existing in nature. This is because they produce sulfuric acid and release metals, which may cause several ecological damages. In Finland, the occurrence of this type of soil in the coastal areas constitutes one of the major environmental problems of the country. To address this problem, it is essential to precisely locate acid sulfate soils. Thus, the creation of occurrence maps for these soils is required. Nowadays, different machine learning methods can be used following the digital soil mapping approach. The main goal of this study is the evaluation of different supervised machine learning techniques for acid sulfate soil mapping. The methods analyzed are Random Forest, Gradient Boosting and Support Vector Machine. We show that Gradient Boosting and Random Forest are suitable methods for the classification of acid sulfate soils, the resulting probability maps have high precision. However, the accuracy of the probability map created with Support Vector Machine is lower because this method overestimates the non-AS soils occurrences. We also compare these modeled probability maps with the conventionally produced occurrence map. In general, the modeled maps are more objective and accurate than the conventional maps. Moreover, the mapping process using machine learning techniques is faster and less expensive. [ABSTRACT FROM AUTHOR]