Development of human health risk-based Soil Quality Standards for Turkey: Conceptual framework

Soil Quality Standards (SQSs) are considered as an important tool for management of contaminated sites. In order to manage adverse effects associated with soil contamination, risk-based SQSs are used worldwide. However, developing health risk-based SQSs is a challenging task. It involves comprehensive assessment of nationwide site characteristics (e.g. soil, hydrogeological, climatic properties), understanding of social behaviors that determine human exposure to soil pollutants (e.g. exposure scenarios and parameters), and making political decisions with regard to the economical concerns. To set fixed levels of SQSs that apply for various cases and that is protective of human health, conservative assumptions should be made. The level of conservativeness of the standards should not pose a challenge to the objectivity of the decision given and not force technical and financial resources. Regarding this challenge, a novel conceptual framework is developed for derivation of human health risk-based SQSs for Turkey. In this paper, the main elements of the established conceptual framework, the methods used for specification of the generic site characteristics, the information sources used for compilation of needed chemical and toxicological data, the political decisions taken, and the challenges encountered during these studies are presented. It is believed that the presented road map developed through the conceptual framework will be beneficial for other countries that are in the stage of deriving SQSs

A geochemical equilibrium modeling approach to assessing soil acidification impacts due to depositions of industrial air emissions

Soil acidification impacts arising from depositions of industrial air emissions may become a serious environmental concern. Currently, in the literature quantitative mechanistic modeling and the experimental acid neutralizing capacity (ANC) approach and a qualitative evaluation approach classifying soils into various levels of sensitivity to acid additions have been reported to assess the long-term soil acidification impacts due to industrial air emissions. Another alternative quantitative approach proposed by this study is the geochemical modeling approach that can be used to similate an ANC curve based on relevant soil chemistry data by calculating the equilibrium distributions of chemical species in the soil solution according to the specified geochemical processes. The purpose of this syudy was essentially to illustrate the potential applications and practical utility of the proposed geochemical modeling approach to assessing soil acidification impacts due to industrial air emissions. The application of the geochemical modeling approach was illustrated by comparisons of the experimental and simulated ANC curves for a calcareous and a noncalcareous soil representing insensitive and sensitive soil cases, respectively. Results obtained from these comparisons reveal that, in terms of producing the ANC curve for the soil solution, the geochemical modeling approach seems to perform well and produce more reliable results for calcareous soil than for noncalcareous soil. However, the approach can also be used for noncalcareous soils when the air emission rates are low and may need further testing with additional measured data for a wide range of soils other than those presented in this study

Sabit ortodontik tedavinin DMFT indeksi ve beyaz nokta lezyonu oluşumu üzerine etkisi

Amaç: Bu çalışmanın amacı sabit ortodontik tedavinin DMFT indeksi ve beyaz nokta lezyonu oluşumu üzerine etkisini değerlendirmektir.Gereç ve Yöntem: Bu çalışmaya sabit ortodontik tedavi gereksinimi olmayan 26 birey (kontrol: Grup A) ve sabit ortodontik tedavi görecek olan 30 birey (test: Grup B) dahil edildi. Grup B’ deki bütün hastalar 0,018 inç slot preadjusted sabit ortodontik apareyler ile tedavi edildi. Tüm bireyler çalışma başlangıcında (T1) ve sonrasında (T2) beyaz nokta lezyonu (BNL) görülme sıklığının tespiti amacıyla Gorelick indeksine göre klinikte muayene edildi. Her birey için T1 ve T2’de DMFT (Çürük, Dolgulu ve Eksik Diş Sayısı) indeksi değeri hesaplandı. DMFT indeksi değerlendirmesinde klinik muayenede Dünya Sağlık Örgütü (DSÖ) kriterleri ve bitewing radyograflar kullanıldı. İstatistik analiz için Kruskal-Wallis ve Mann-Whitney U testleri kullanıldı.Bulgular: İki grup arasında DMFT indeksi değişimi anlamlı bulunmazken, Grup B’de BNL oluşumu (%66,6) Grup A’ya göre (%26,9) anlamlı derecede yüksek bulundu (p=0,000). Grup B’de BNL oluşumu ve DMFT indeksi ve cinsiyet arasında ilişki bulunamadı. Sabit ortodontik tedavi sonrasında en çok BNL oluşumunun alt birinci büyük azı dişler (%28,8), alt ikinci küçük azı dişler (%23,2) ve üst yan kesici dişlerde (%19,2) oluştuğu belirlendi.Sonuç: Sabit ortodontik tedavi görmekte olan  bireylerde beyaz nokta lezyonu oluşumunun önlenmesi için bireylerin ağız bakım alışkanlıklarının iyileştirilmesi ve ilave flor desteğinin arttırılmasının gerekli olduğu düşünülmektedir.Anahtar kelimeler: DMFT, Beyaz nokta lezyonu, Sabit ortodonti tedavisi. THE EFFECT OF FIXED ORTHODONTIC TREATMENT ON DMFT INDEX AND WHITE SPOT FORMATION AbstractAim: The aim of this study was to assess the effect of fixed orthodontic treatment on DMFT index and white spot lesion formationSubjects and Methods: Fifty six patients (Group A: 26 subjects; Group B: 30 subjects) who were undergoing fixed orthodontic treatment were invited to participate in this study.  All patients in Group B were treated with a 0.018 inch slot preadjusted fixed orthodontic appliances. An examiner used the Gorelick index for assessment of white spot lesion (WSL) on the buccal surface of teeth before (T1) and after (T2) treatment. The DMFT index value was recorded for each subject at T1 and T2. The WHO (World Health Organization) criteria and bitewing radiographs were utilized to diagnose the carious status of the subjects. Kruskal-Wallis and Mann-Whitney U tests were used to compare the groups.Results: No differences was found between the groups in terms of increased DMFT. On the other hand, The mean increase in WSL percentage in Group B (%66,6) and Group A (%26,9), respectively (p=0,000). In Group B, gender not significantly related to the DMFT index and development of new WSL. The greatest prevalence of WSLs was found in the mandibular first molars (%28,8), followed by the mandibular second premolars (%23,2) and the maxillary lateral incisors (%19,2).Conclusion: A more effective oral care support should be provided to subjects and caries preventive procedures (fluor therapy) should be done.Key words: DMFT, White Spot Lesion, Fixed Orthodontic Treatmen

Attomolar sensitivity microRNA detection using real-time digital microarrays.

MicroRNAs (miRNAs) are a family of noncoding, functional RNAs. With recent developments in molecular biology, miRNA detection has attracted significant interest, as hundreds of miRNAs and their expression levels have shown to be linked to various diseases such as infections, cardiovascular disorders and cancers. A powerful and high throughput tool for nucleic acid detection is the DNA microarray technology. However, conventional methods do not meet the demands in sensitivity and specificity, presenting significant challenges for the adaptation of miRNA detection for diagnostic applications. In this study, we developed a highly sensitive and multiplexed digital microarray using plasmonic gold nanorods as labels. For proof of concept studies, we conducted experiments with two miRNAs, miRNA-451a (miR-451) and miRNA-223-3p (miR-223). We demonstrated improvements in sensitivity in comparison to traditional end-point assays that employ capture on solid phase support, by implementing real-time tracking of the target molecules on the sensor surface. Particle tracking overcomes the sensitivity limitations for detection of low-abundance biomarkers in the presence of low-affinity but high-abundance background molecules, where endpoint assays fall short. The absolute lowest measured concentration was 100 aM. The measured detection limit being well above the blank samples, we performed theoretical calculations for an extrapolated limit of detection (LOD). The dynamic tracking improved the extrapolated LODs from femtomolar range to [Formula: see text] 10 attomolar (less than 1300 copies in 0.2 ml of sample) for both miRNAs and the total incubation time was decreased from 5 h to 35 min.K99 AI167063 - NIAID NIH HHSPublished versio

Transport of metals leaching from land-disposed oil field wastes

The potential for groundwater contamination by metals leaching from land-disposed oil field exploration and production (E&P) wastes is an environmental concern. In this study a geochemical transport model is adopted to consider multispecies metal migration. Objectives are to characterize the chemical composition of E&P wastes, to evaluate the mobility and pollution potential of metals in E&P wastes and to investigate the utility of simplified modelling approaches. A chemical transport model coupling a hydrologic submodel is used for the analysis. The hydrologic transport submodel considers one-dimensional advective-dispersive transport: of components in the aqueous phase under steady unsaturated flow conditions. The geochemical submodel considers speciation, precipitation-dissolution and ion exchange reactions assuming local equilibrium conditions prevail. Simulations are performed to evaluate the movement of metals through the unsaturated zone for the base case corresponding to a typical waste pit. Sensitivity analyses are performed for selected input parameters that are expected to have significant effect on metal transport. Breakthrough curves (BTCs) are obtained for metal species As, Ba, Cd, Cr, Cu, Pb and Zn at the water table. Inspection of BTCs reveals multiple peaks and complex interrelationships among model parameters which cannot be reproduced using single species transport models with linear reaction terms. Precipitation plays a significant role in attenuation of metal concentrations in E&P wastes. Calculated vadose zone attenuation ratios indexing the pollution potential of various metals span a wide range of values due to the differences in reactivity of metals. Results for the relative vadose zone concentration with respect to maximum contaminant levels in drinking water suggest that, in general, chloride is likely to to be more critical than trace metals in controlling the groundwater quality. Cadmium and copper are the next most likely to lead to non compliance. Under conditions where Cr(III) is the dominant species in waste, chromium attenuation is greatly increased due to precipitation

ASSESSING RISK OF GROUNDWATER POLLUTION FROM LAND-DISPOSED WASTES

A stochastic modeling approach for the migration of contaminants in soil and ground-water is developed to assess the expected magnitude of contamination at receptors located downgradient from a waste pit. The model evaluates uncertainties in contaminant concentrations due to uncertainties in waste composition and hydrogeologic properties of waste sites, and determines the exceedance probabilities of a specified concentration level at receptor points using Monte Carlo (MC), first order (FO), and point-estimate (PE) methods. A lognormal distribution is assumed for concentration at a receptor point in application of the FO and PE methods to assess exceedance probabilities. A comparison of the three error-analysis methods is performed to evaluate the efficiency and accuracy of the FO and PE methods relative to the MC method. Results suggest that for nonadsorbing and conservative contaminants, the level of accuracy provided by the FO method is comparable with that of the MC method. For nonconservative contaminants, both FO and PE methods compared less favorably with the MC results

Kuzey Kıbrıs Türk Cumhuriyeti (KKTC) Güzelyurt Akiferi’nin Sayısal Modellenmesi

Proje ÖzetiKuzey Kıbrıs Türk Cumhuriyeti (KKTC)’ deki sınırlı miktardaki mevcut su kaynakları arasında, Güzelyurt Akiferi ülkenin en önemli ve aynı zamanda en büyük içme, kullanma ve sulama suyu kaynağıdır. Ancak, yoğun talep karşısında beslenim ve boşalım dengesi gözetilmeksizin yapılan aşırı ve kontrolsüz su çekimleri sonucunda akiferdeki su rezervinin yıllar içerisinde ciddi olarak azalması ve denize yakın kesimlerde deniz suyu girişimi nedeniyle tuzlanarak su kalitesinin ciddi ölçüde bozulması, Güzelyurt Akiferinin karşı karşıya bulunduğu önemli sorunlar olarak tespit edilmektedir. KKTC’de yoğun bir şekilde yaşanan su kıtlığı sorununa uzun vadeli çözüm getirme amacına yönelik olarak, Türkiye Cumhuriyeti tarafından “KKTC Su Temin Projesi” geçtiğimiz aylarda uygulamaya konmuştur. Bu projenin önemli katkılarından birisi de halen Güzelyurt Akiferi üzerinde yoğun su talebi nedeniyle oluşan aşırı stresin ciddi ölçüde azaltılacak olması ve bunun sonucu olarak da orta ve uzun vadede akiferin beslenim/boşalım dengesinin yeniden tesis edilerek rehabilite edilmesi imkânının ortaya çıkmasıdır. Bu çerçevede önerilen projede, Güzelyurt Akiferi’nin günümüz modern teknolojilerinden Coğrafi Bilgi Sistemleri (CBS) ve sayısal modelleme teknikleri ile entegre sistem modelleme yaklaşımı kullanılarak, üç-boyutlu (3-B) ayrıntılı kavramsal ve sayısal simülasyon modelinin geliştirilmesi amaçlanmaktadır. Bu amaca yönelik olarak, KKTC Jeoloji ve Maden Dairesi (J&MD) bünyesinde bulunan Güzelyurt Akiferi ile ilgili mevcut jeolojik, hidrolojik ve hidrojeolojik veriler; J&MD nin yürüttüğü izleme çalışmalarıyla toplanan aylık su seviyesi ve su kalitesi (EC, Cl, pH vb) verileri ile pompaj kuyularından yapılan su çekimlerine yönelik derlenen veriler kullanılacaktır. Sayısal modelin geliştirilmesinde ise GMS10.0 yazılımı kullanılacaktır. Proje, veri derleme; veri analizi ve kavramsal modelin geliştirilmesi; sayısal simülasyon modelinin kurulumu, kalibrasyonu ve doğrulanması; simülasyon senaryolarının tanımlanması ve simülasyonların yapılması olmak üzere toplam 4 iş paketinden oluşmaktadır; ve toplam 24 ay sürelidir