Steel slag leachates : environmental risks and metal recovery opportunities

Steel slag wastes are large volume residues generated in increasing quantities globally during steel production. While there are many afteruses for slag, roughly a quarter produced globally is stockpiled or landfilled where it may pose environmental risks. Furthermore as resource pressures increase there is a growing interest in recovering valuable metals from industrial by-products. Given the uncertainties in environmental risks and opportunities for further valorisation of wastes, an improved understanding of leaching processes from steel slag would help inform long term management of these industrial by-products. This thesis aims to investigate a series of alkaline disposal sites (both steel slag and limespoil) to improve our understanding of the geochemical nature and fate of notable contaminants, as well as valuable metals of interest, in highly alkaline settings. The results of the field investigations show that leachates are characterised by high pH (> 11) and negative redox potential, excess deposition of secondary precipitates, and increased mobility of lithium (>800 ppb), strontium (>2500 ppb) and vanadium (>50 ppb), present in concentrations greater than those typically encountered in natural surface waters. Furthermore, these slag deposits were enriched with less mobile elements such as molybdenum (60 ppb) and nickel (61 ppb) with associated low environmental concern, but high resource value.Laboratory batch tests showed that acid leaching promotes the leaching of the elements of interest particularly vanadium. However, such approach may not be viable at legacy sites due to cost. On the other hand, compost amendment of slag enhanced the leaching of molybdenum and vanadium by a factor of 3.6 and 2.5 respectively above water leaching alone. Column experiments reinforced these patterns in showing enhanced leaching of vanadium, molybdenum, and lithium when organic amendment is in contact with hyperalkaline leachate under aerobic conditions. This is most likely due to alkaline hydrolysis of organics within the system and subsequent metal complexation. Analysis of secondary precipitates (notably calcium and magnesium carbonates) forming around the slag suggest these are key in controlling solubility of contaminants and metals of potential resource value (e.g. Ni)

Rapid recovery of benthic invertebrates downstream of hyperalkaline steel slag discharges

This study assesses the physical and chemical characteristics of hyperalkaline steel slag leachate from a former steelworks on two streams in England and their impacts on benthic invertebrate communities. Using multivariate methods (CCA), we related invertebrate richness and diversity with chemical parameters along the environmental gradient from point sources to less impacted sites downstream. Point discharges are characterised by high pH (10.6–11.5), high ionic strength (dominated by Ca–CO₃–OH waters), elevated trace elements (notably Li, Sr and V) and high rates of calcium carbonate precipitation. This combination of stressors gives rise to an impoverished benthic invertebrate community in source areas. The total abundance, taxonomic richness and densities of most observed organisms were strongly negatively correlated with water pH. Analysis using biological pollution monitoring indices (e.g. BMWP and Functional Feeding Groups) shows the system to be highly impacted at source, but when pH approaches values close to aquatic life standards, some 500 m downstream, complex biological communities become established. In addition to showing the rapid recovery of invertebrate communities downstream of the discharges, this study also provides a baseline characterisation of invertebrate communities at the extreme alkaline range of the pH spectrum

Pengaruh Cuka Salak terhadap Penurunan Glukosa Darah dan Histopatologi Pankreas Tikus Diabetes

Diabetes mellitus is indicated by elevated levels of blood glucose and progressive changes of the structure of pancreatic islet histopathology. Salacca vinegar made from suwaru salacca is one of alternative medicine of diabetes because contain acetate acid and antioxidant. The aim of this study is to investigate the effects of salacca vinegar on blood glucose and histopathologycal of pancreas of diabetic rats. This research is based on Pre and Post Test with Control Group Design. Ratus norvegicus rats were divided into 4 groups. There were normal group, diabetes, diabetes + salacca vinegar 0,4mL and diabetes + salacca vinegar 0,7mL. The results indicated that salacca vinegar had a significant blood glucose lowering effect diabetic rats. Group of diabetes + salacca vinegar 0,4mL reduced glucose concentration of 35,06%, diabetes + salacca vinegar 0,7mL of 32,50%. Based on histopathologycal of pancreas showed that salacca vinegar recover pancreatic beta cells damaged. Conclusion is salacca vinegar had a significant blood glucose lowering effect and recover pancreatic beta cells damaged

Methyl Jasmonate-Induced Stimulation of Sarcoplasmic Reticulum Ca 2ϩ -ATPase Affects Contractile Responses in Rat Slow-Twitch Skeletal Muscle

ABSTRACT The purpose of this study was to determine whether methyl jasmonate, a stimulator of Ca 2ϩ -adenosine triphosphatase (ATPase) activity of the purified ATPase from fast-twitch skeletal muscle, could affect contractile responses in small bundles of rat isolated slow-twitch (soleus) fibers. In saponin-skinned fibers, sarcoplasmic reticulum (SR) Ca 2ϩ loading was performed in pCa 7.0 solution. The amount of Ca 2ϩ taken up was monitored by use of the amplitude of contraction following application of 10 mM caffeine. Results indicate that the increased loading rate in the presence of methyl jasmonate is likely due to stimulation of the SR Ca 2ϩ -ATPase. In Triton-skinned fibers, the myofibrillar Ca 2ϩ sensitivity was not changed by methyl jasmonate (50 -200 M). In intact fibers, the amplitude and the time constant of relaxation of twitch and potassium contracture were reversibly reduced after 2 min of application of methyl jasmonate at a concentration of up to 125 M. At higher concentrations (Ͼ150 M), effects were not reversible. In the presence of methyl jasmonate (100 M), the relationship between the amplitude of potassium contractures and the membrane potential shifted to more positive potentials, whereas the steady-state inactivation curve was unchanged. These observations suggest that methyl jasmonate has no effect on voltage sensors. Taken together, our results show that methyl jasmonate is a potent, reversible, and specific stimulator of the SR Ca 2ϩ pump in slow-twitch skeletal muscle and is an extremely valuable pharmacological tool for improving relaxation and studying calcium-signaling questions

Identification of novel porcine and bovine parvoviruses closely related to human parvovirus 4

Human parvovirus 4 (PARV4), a recently discovered parvovirus found exclusively in human plasma and liver tissue, was considered phylogenetically distinct from other parvoviruses. Here, we report the discovery of two novel parvoviruses closely related to PARV4, porcine hokovirus (PHoV) and bovine hokovirus (BHoV), from porcine and bovine samples in Hong Kong. Their nearly full-length sequences were also analysed. PARV4-like viruses were detected by PCR among 44.4% (148/333) of porcine samples (including lymph nodes, liver, serum, nasopharyngeal and faecal samples), 13% (4/32) of bovine spleen samples and 2% (7/362) of human serum samples that were sent for human immunodeficiency virus and hepatitis C virus antibody tests. Three distinct parvoviruses were identified, including two novel parvoviruses, PHoV and BHoV, from porcine and bovine samples and PARV4 from humans, respectively. Analysis of genome pequences from seven PHoV strains, from three BHoV strains and from one PARV4 strain showed that the two animal parvoviruses were most similar to PARV4 with 61.5-63% nt identities and, together with PARV4 (HHoV), formed a distinct cluster within the family Parvoviridae. The three parvoviruses also differed from other parvoviruses by their relatively large predicted VP1 protein and the presence of a small unique conserved putative protein. Based on these results, we propose a separate genus, Hokovirus, to describe these three parvoviruses. The co-detection of porcine reproductive and respiratory syndrome virus, the agent associated with the recent 'high fever' disease outbreaks in pigs in China, from our porcine samples warrants further investigation. © 2008 SGM.published_or_final_versio

Institutional risk factors for norovirus outbreaks in Hong Kong elderly homes: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>Most of the institutional outbreaks of norovirus in Hong Kong occur in elderly homes, the proportion being 69% in 2006. Residents in elderly homes are a special population seriously affected by norovirus infections, it is necessary to investigate the risk factors of the norovirus outbreaks in Hong Kong elderly homes at the facility level.</p> <p>Methods</p> <p>A cohort of 748 elderly homes was followed up from January 2005 to December 2007; each elderly home was treated as one observation unit and the outcome event was the norovirus outbreak. Cox regression models were fitted to estimate the rate ratio (RR) and 95% confidence interval (CI) for the potential risk factors.</p> <p>Results</p> <p>A total of 276 norovirus outbreaks were confirmed during the study period; the outbreak rate was 12.2 (95% CI: 9.9-14.6) per 100 home-years; elderly homes with a larger capacity (RR = 1.4, 95% CI: 1.3-1.5 (per 30-resident increment)), a higher staff-to-resident ratio (RR = 1.2, 95% CI: 1.1-1.3 (per 1/30 increment) and better wheelchair accessibility (RR = 2.0, 95% CI: 1.3-3.2) were found to have an elevated norovirus outbreak rate in Hong Kong elderly homes; Elderly homes with partitions between beds had a lower rate of norovirus outbreaks (RR = 0.6, 95% CI: 0.4-0.8).</p> <p>Conclusions</p> <p>Elderly home capacity, staff-to-resident ratio and wheelchair accessibility were risk factors for norovirus outbreaks in Hong Kong elderly homes. Partitions between beds were a protective factor of norovirus outbreaks. These results should be considered in the infection control in Hong Kong elderly homes.</p

Alkaline residues and the environment: A review of impacts, management practices and opportunities

Around two billion tonnes of alkaline residues are produced globally each year by industries such as steel production, alumina refining and coal-fired power generation, with a total production estimate of 90 billion tonnes since industrialization. These wastes are frequently stored in waste piles or landfills, and can be an environmental hazard if allowed to generate dust, or if rainwater infiltrates the waste. This review will focus on the environmental impacts associated with alkaline residues, with emphasis on the leachates produced by rainwater ingress. Many alkaline industrial wastes can produce leachates that are enriched with trace metals that form oxyanions (e.g. As, Cr, Mo, Se, V), which can be very mobile in alkaline water. The management options for the residues and their leachates are also discussed, distinguishing active and passive treatment options. Potential reuses of these materials, in construction materials, as agricultural amendments, and in environmental applications are identified. The mechanisms of carbon sequestration by alkaline residues are assessed, and the potential for enhancing its rate as a climate change off-setting measure for the industry is evaluated. The potential for recovery of metals critical to e-technologies, such as vanadium, cobalt, lithium and rare earths, from alkaline residues is considered. Finally research needs are identified, including the need to better understand the biogeochemistry of highly alkaline systems in order to develop predictable passive remediation and metal recovery technologies

Peran Radiografik Sistem Radiografi Dalam Mendeteksi Karies Dibandingkan Dengan Sinar X Konvensional

Dari hasil penel itian mengenai perbandingan hasil kualitas radiografik pada sistem R . V.G dan radiografik konvensional dalam mendiagnosis karies aproksimal gigi, kesimpulan yaitu : dapat ditarik Tidak terdapat perbedaan hasil kualitas radiografik pada sistem Radiovisiog rafi dan radiografik konvensional dalam mendiagnosis karies aproksimal. Dari hasil nilai distribusi berdasarkan waktu paparan dan ada tidaknya ka ries a proksimal didapatkan bahwa sistem R.V.G mempunyai nilai lebih rendah dibanding sistem radiografik konvensional. Waktu paparan yang dibutuhkan untuk mendapatkan hasil kualitas radiografik yang optimal adalah 0,6 detik pada radiografik konvensional dan 0,06 detik pada sistem R. V. G

PERANAN ORANG TUA TERHADAP SKOR DEBRIS INDEKS PADA ANAK (STUDI LITERATUR)

Hapsari, Oty., 2021. Peran Orang Tua Terhadap Skor Debris Indeks pada Anak (Studi Literatur), Karya Tulis Ilmiah, Jurusan Keperawatan Gigi Politeknik Kesehatan Kemenkes Semarang, Pembimbing : (I) Tri Wiyatini, SKM. M.Kes (Epid), (II) dr. Endra Nastiti DonasariBerdasarkan Riset Kesehatan Dasar (Riskesdas) tahun 2018 di Indonesia proporsi masalah kesehatan gigi dan mulut sebesar 57,6% dan yang mendapatkan pelayanan dari tenaga medis gigi sebesar 10,2%. Adapun proporsi perilaku menyikat gigi setiap hari sebesar 94,7% dengan proporsi menyikat gigi yang benar adalah sebesar 2,8%. Kesehatan gigi dan mulut merupakan hal penting dan harus dijaga kebersihannya. Agar terbentuknya kebersihan gigi yang optimal diperlukan kedisplinan peran orang tua yang besar. Penelitian ini bertujuan untuk mengetahui peran bimbingan orang tua tehadap skor debris indeks dalam mendampingi anak untuk menjaga kebersihan gigi dan mulut. Jenis penelitian ini merupakan studi kepustakaan, dengan sumber literatur maupun jurnal. Variabel pengaruh penelitian ini adalah peran orang tua dan variabel terpengaruhnya adalah skor debris indeks.Hasil studi literatur menunjukan terdapat peran orang tua terhadap skor debris indeks pada anak dengan kriteria baik yaitu 65,2%. Hal ini walaupun peran orang tua cukup baik belum tentu anak disiplin menjaga kebersihan gigi dan mulut. Oleh karena itu diharapkan peran orang tua yang besar dalam mendampingi anak menjaga kebersihan gigi dan mulut. Kata kunci : Peran Orang Tua, Skor Debris Indek