Comparative characterization of microbial communities that inhabit PFAS-rich contaminated sites: A case-control study.

The historic usage and discharge of per- and polyfluoroalkyl substances (PFAS) containing chemicals have produced many contaminated sites and PFAS contamination has become a global concern due to their persistence, widespread distribution, and potential adverse impacts for human and environmental health. However, there have been limited investigations on the specific behavior of bacterial communities in PFAS contaminated soils. In this study, a quantitative PCR assay and Illumina MiSeq sequencing were used to investigate the variations of bacterial communities in a regional Australian airport contaminated with PFAS. The dominate PFAS detected in soil samples was Perfluorooctanesulfonic acid (PFOS), which accounted for 82% of total PFAS and the maximum PFOS level was noted (20,947±1824 ng.PFOS/mg.Soil) at the top soil. Irrespective of the degree of PFAS contamination at different depths, the comparable percentile contribution of each PFAS was observed in soil samples. Significantly higher bacteria amplicon sequence variant (ASV) and diversity were noted in uncontaminated soil than PFAS contaminated soil. Bacterial genera Rhodanobacter and Chujaibacter were dominant in the PFAS contaminated soil. Three different bacterial genera of Alphaproteobacteria, Ambiguous taxa of Acidobacteriia, and genus Chujaibacter of Gammaproteobacteria showed a significant positive correlation and RB41, Gaiella showed a significant negative correlation with 11 different PFAS concentrations. Overall, the results presented in this study suggest that the counts and species diversity of soil microorganisms are adversely influenced by PFAS contamination.

In situ soil flushing to remediate confined soil contaminated with PFOS- an innovative solution for emerging environmental issue.

PerFluoroOctane Sulfonate (PFOS), is a toxic anthropogenic chemical that has been produced and gradually released into the environment for the past seven decades. An accurate audit of global PFOS contamination and contaminated sites are yet to be published. The available technologies to remediate PFOS contaminated soil are limited and often basic strategies such as temporary soil containment are adopted as immediate measures to manage the contaminated sites. In this study, the in situ soil flushing technique is assessed for its capacity to remediate soil contaminated with PFOS. A complete treatment process with several operation units was proposed such as solvent flushing, ground water pumping, solvent recovery and water treatment for PFOS. Potential solvents were identified and it was observed that more than 98% PFOS removal could be attained by flushing with five bed volumes of 50% ethanol. In addition, the study investigated thirteen commercially available filter materials and identified PFA694E, K6362, MP 62, Amberlite IRA 67 and Dowexoptopore V493 as suitable to eliminate PFOS with competitive PFOS adsorption characteristics. The proposed method can be recommended to remediate PFOS in recognised contaminated soils, such as those at defence sites. Furthermore, a contaminated site with favourable characteristics to implement the suggested method was identified in Australia and described in this paper.

The Influence of fluoride on chronic kidney disease of uncertain aetiology (CKDu) in Sri Lanka.

Fluoride is an element that is widely distributed in the environment. The involvement of fluoride in pathogenesis of Chronic Kidney Disease of uncertain aetiology (CKDu) in Sri Lanka is a much-debated topic. This study aimed to investigate the fluoride concentration in drinking water in CKDu affected areas in Sri Lanka and to evaluate the possible effect of renal impairment on serum fluoride levels in CKDu patients. Drinking water (n = 60) from the common water sources from two CKDu prevalent areas and serum samples of CKDu patients (n = 311) and healthy controls (n = 276) were collected. Both environmental and biological samples were analysed for the concentration of fluoride. The fluoride concentration in over 95% of drinking water samples was below the WHO guideline of 1.5 mg/L. Serum fluoride concentrations in majority of the unaffected and early-stage CKDu patients (stages 1 and 2, eGFR >60 ml/min/1.73m2) were below the normal upper concentration of 50 µg/l and significantly higher levels were observed in patients in late stages of CKDu compared to the healthy controls. The available guidelines for drinking water are solely based on healthy populations with normal renal function. But, it is evident that once the kidney function is impaired, patients enter a vicious cycle as fluoride gradually accumulates in the body, further damaging the kidney tissue. Thus, close monitoring of serum fluoride levels in CKDu patients and establishing health-based target guidelines for fluoride in drinking water for the CKDu patients are recommended to impede the progression to end stage renal disease.

Systematic evaluation of exposure to trace elements and minerals in patients with chronic kidney disease of uncertain etiology (CKDu) in Sri Lanka.

Chronic kidney disease of uncertain etiology (CKDu) in areas in and around Sri Lanka's North Central Province has been identified as a major non-communicable disease due to its high prevalence and the burden on the public health system. Controversial evidence relating to the etiology and risk factors of CKDu has been reported. The most debated is the role of trace elements such as Cd and As in the pathogenesis of CKDu. Urine and hair samples collected from CKDu patients and healthy controls were measured for the concentration of different elements including Cd and As. To assess the possible environmental exposures, drinking water and rice samples collected from the affected areas as well as unaffected areas in the country were analyzed. Transmission electronic microscopic analysis of renal biopsies from CKDu patients was also performed. Analysis of drinking water and rice samples indicated that the levels of all minerals and trace elements analyzed including Cd and As were within the levels recommended by World Health Organization and Sri Lanka drinking water guidelines and did not suggest any form of contamination. Analysis of biological samples, including urine, hair and renal tissue, did not provide evidence to support Cd or As toxicity in CKDu patients. Overall, the observations of this integrated, comprehensive study, which included biological, environmental and pathological investigations, strongly support our previous reports on the absence of Cd and As toxicity in areas with high prevalence of CKDu. Further, these observations do not provide evidence on the involvement of Cd and As in pathogenesis of CKDu in Sri Lanka.

Whole-exome sequencing reveals genetic variants associated with chronic kidney disease characterized by tubulointerstitial damages in North Central Region, Sri Lanka.

OBJECTIVES: The familial clustering observed in chronic kidney disease of uncertain etiology (CKDu) characterized by tubulointerstitial damages in the North Central Region of Sri Lanka strongly suggests the involvement of genetic factors in its pathogenesis. The objective of the present study is to use whole-exome sequencing to identify the genetic variants associated with CKDu. METHODS: Whole-exome sequencing of eight CKDu cases and eight controls was performed, followed by direct sequencing of candidate loci in 301 CKDu cases and 276 controls. RESULTS: Association study revealed rs34970857 (c.658G > A/p.V220M) located in the KCNA10 gene encoding a voltage-gated K channel as the most promising SNP with the highest odds ratio of 1.74. Four rare variants were identified in gene encoding Laminin beta2 (LAMB2) which is known to cause congenital nephrotic syndrome. Three out of four variants in LAMB2 were novel variants found exclusively in cases. CONCLUSION: Genetic investigations provide strong evidence on the presence of genetic susceptibility for CKDu. Possibility of presence of several rare variants associated with CKDu in this population is also suggested.

Perfluorinated carboxylic acids discharged from the Yodo River Basin, Japan.

We investigated perfluorinated carboxylic acids (PFCAs) with 7-14 carbon atoms (C7-C14) in the Yodo River system in 2013. C7-C11 were detected at most sampling sites. The range and median of total PFCAs (ΣPFCAs) concentrations were 1.0-89.7 and 11.2 ng L(-1), respectively. The dominant component was C8 (average for all samples=53.3±8.8%), followed by C7 (19.2±6.7%) and C9 (17.6±7.1%). The levels of C8 were confirmed to decrease greatly over the last 10 years. We assessed the fluxes in C7-C11 discharged from the basin based on the concentrations in river water and river flow rate. The flux of discharged ΣPFCAs was 237.0 g d(-1) at the most downriver point of the assessment areas. Considering the variability in flow rate due to precipitation, the annual ΣPFCAs flux was estimated to be 86.5-173.4 kg y(-1). Identification and quantification of PFCAs sources is difficult because the strength of the sources changes with time, and available information is quite limited. Further monitoring and investigation are necessary to understand sources of PFCAs, as well as their potential for human exposure.

An integrative study of the genetic, social and environmental determinants of chronic kidney disease characterized by tubulointerstitial damages in the North Central Region of Sri Lanka.

OBJECTIVES: Previous investigations on chronic kidney disease of unknown etiology characterized by tubulointerstitial damages (CKDu) in the North Central Region (NCR) of Sri Lanka have supported the involvement of social, environmental and genetic factors in its pathogenesis. METHODS: We conducted a social-environmental-and-genetic epidemiology study on a male population in NCR to investigate the genetic and environmental contributors. We recruited 311 case-series patients and 504 control candidates. Of the 504 control candidates, 218 (43%) were eliminated because of the presence of hypertension, proteinuria, high HbA1c, high serum creatinine or high alpha-1 microglobulin in urine. RESULTS AND DISCUSSION: None of 18 metals measured (µg//) in urine, including Cd, As and Pb, showed significantly higher concentrations in cases compared with controls. As speciation results showed that 75-80% of total urinary As was in the form of arsenobetaine, which is non-toxic to humans. None of the metal concentrations in drinking water samples exceeded guideline values. A genome-wide association study (GWAS) was conducted to determine the genetic contributors. The GWAS yielded a genome-wide significant association with CKDu for a single nucleotide polymorphism (SNP; rs6066043; p=5.23 × 10(-9) in quantitative trait locus analysis; p=3.73 × 10(-9) in dichotomous analysis) in SLC13A3 (sodium-dependent dicarboxylate transporter member 3). The population attributable fraction and odds ratio for this SNP were 50% and 2.13. Genetic susceptibility was identified as the major risk factor for CKDu. However, 43% of the apparently healthy male population suffers from non-communicable diseases, suggesting their possible influence on CKDu progression.

P.R4810K, a polymorphism of RNF213, the susceptibility gene for moyamoya disease, is associated with blood pressure.

BACKGROUND: Moyamoya disease-an idiopathic vascular disorder of intracranial arteries-is often accompanied by hypertension. RNF213 has been identified as a susceptibility gene for moyamoya disease. In the present study, the association of p.R4810K (G>A) with blood pressure (BP) was investigated in a Japanese population. METHODOLOGY/PRINCIPAL FINDINGS: Three independent study populations, the Nyukawa (n = 984), Noshiro (n = 2,443) and Field (n = 881) studies, joined this study. BP, body weight and height were measured. Past and present symptoms and disease and medication histories were assessed by interview. Associations of p.R4810K (rs112735431, ss179362673) of RNF213 with BP were investigated. Two linkage disequilibrium blocks were constructed for moyamoya patients with p.R4810K (n = 140) and the general population (n = 384) using 39 single nucleotide polymorphisms (SNPs) spanning 390 kb around RNF213. A total of 60 carriers (3 for AA genotype and 57 for GA genotype) were found in these samples, and the minor allele frequencies were 1.4 % in the Nyukawa and Field studies and 0.2 % in the Noshiro study. Regression analyses adjusted for age, sex and body mass index based on an additive model demonstrated significant associations with systolic BP (mmHg/allele): ß (standard error) was 8.2 (2.9) in the Nyukawa study (P = 4.7 × 10(-3)), 18.7 (5.4) in the Noshiro study (P = 4.6 × 10(-4)) and 8.9 (2.0) (P = 1.0 × 10(-5)) in the three populations. In contrast, diastolic BP showed significant associations only in the Noshiro study. Linkage disequilibrium blocks contained none of the BP-associated proxy SNPs reported by previous studies. CONCLUSIONS/SIGNIFICANCE: Our study suggests that p.R4810K of RNF213 is associated strongly with systolic BP.

Evidence of tubular damage in the very early stage of chronic kidney disease of uncertain etiology in the North Central Province of Sri Lanka: a cross-sectional study.

BACKGROUND: In the North Central Province of Sri Lanka, chronic kidney disease of uncertain etiology (CKDue) has increased markedly over the past 15-20 years. METHODS: From around 4,700 patients who were followed up, 106 affected patients who visited two local clinics in the endemic area for CKDue on August 10, 2009 and 10 pedigrees of 10 of these cases with familial clustering of CKDue participated in this study. Urine samples, collected from affected patients (n = 106), unaffected relative controls (n = 81), and Japanese controls (n = 50), were analyzed for two tubular markers: α1-microglobulin and N-acetyl-ß-D: -glucosaminidase. Urine samples from patients with CKDue stages 1-4 (n = 101) and all the samples from unaffected relatives and Japanese controls were analyzed for urinary cadmium concentration. RESULTS: Urinary excretion of α1-microglobulin was elevated even in the earliest stage of CKDue compared with its levels in unaffected relative controls. Urinary excretion of N-acetyl-ß-D: -glucosaminidase was elevated only in stage 5. In contrast, urinary cadmium excretion was similar in CKDue patients and in the unaffected relative controls, and levels in both these groups were significantly lower than the level in the Japanese controls. All levels were below the threshold level for renal toxicity, indicating the absence of any evidence of cadmium toxicity. CONCLUSIONS: The present study indicates that renal tubular damage occurs in the very early stage of CKDue and demonstrates the existence of familial clustering, suggesting that CKDue is likely to be the outcome of exposure to an unknown nephrotoxin in susceptible subjects in the endemic region.

Tubulointerstitial damage as the major pathological lesion in endemic chronic kidney disease among farmers in North Central Province of Sri Lanka.

Chronic kidney disease of uncertain etiology (CKDu) in North Central Province of Sri Lanka has become a key public health concern in the agricultural sector due to the dramatic rise in its prevalence and mortality among young farmers. Although cadmium has been suspected as a causative pathogen, there have been controversies. To date, the pathological characteristics of the disease have not been reported. Histopathological observations of 64 renal biopsies obtained at Anuradhapura General Hospital from October 2008 to July 2009 were scored according to Banff 97 Working Classification of Renal Allograft pathology. The correlations between the histological observations and clinical parameters were statistically analyzed. Interstitial fibrosis and tubular atrophy with or without nonspecific interstitial mononuclear cell infiltration was the dominant histopathological observation. Glomerular sclerosis, glomerular collapse, and features of vascular pathology such as fibrous intimal thickening and arteriolar hyalinosis were also common. Although hypertension was identified as one of the common clinical features among the cases, it did not influence the histopathological lesions in all the cases. This study concludes that tubulointerstitial damage is the major pathological lesion in CKDu. Exposure(s) to an environmental pathogen(s) should be systematically investigated to elucidate such tubulointerstitial damage in CKDu.

Adsorption of four perfluorinated acids on non ion exchange polymer sorbents.

Perfluorinated compounds (PFCs) have attracted global concern due to their ubiquitous distribution and properties of persistence, bio accumulation and toxicity. The process of adsorption has been identified as an effective technique to remove PFCs in water. Different non ion-exchange polymeric adsorbents were tested with regard to their sorption kinetics and isotherms at low PFCs concentrations. Selected PFCs were perfluorobutanoic acid (PFBA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA) and perfluorodecanoic acid (PFDA) and the tested polymers were three types of Dowex optopores (V-493, V503, and L493), Amberlite XAD-4, and Filtrasorb 400 (Granular Activated Carbon-GAC). We observed the selective adsorption of PFCs on synthetic polymers. For PFDA, Amberlite XAD-4 gave the Freundlich adsorption constant of 2,965 (microg PFCs/g sorbent)(microg PFCs/L)(-n), which was higher than that of GAC (121.89 (microg PFCs/g sorbent) (microg PFCS/L)(-n)). In the case of PFBA, GAC showed better performance (13.36) (microg PFCs/g sorbent) microg PFCS/L)(-n) than synthetic polymers (0.62-5.23) (microg PFCs/g sorbent) (microg PFCS/L)(-n). Adsorption kinetics of all adsorbents were well described (R2 = 0.85-1) by pseudo-second order kinetic model. Sorption capacity was influenced by initial PFCs concentration for all adsorbents. GAC reached the equilibrium concentration within 4 hours, Amberlite XAD 4 reached it within 10 hours and other polymers took more than 70 hours.

Historical trends in human dietary intakes of endosulfan and toxaphene in China, Korea and Japan.

Recently, the Stockholm Convention prohibited the use of toxaphene and has been reviewing endosulfan. The historical use of these pesticides may contaminate food and tend to accumulate in the food chain. In this study, to evaluate the spatial and temporal trends of food contamination, the endosulfan and toxaphene levels were measured in pooled 24-h food composite samples from Chinese (n=10), Korean (n=10) and Japanese (n=40) adults in the 1990s and 2007-2009. Endosulfan was detected in 32 of 40 samples from Japan, but its levels (sum of α- and ß-isomers) were low in both the 1990s and 2009 (range as geometric mean (geometric standard deviation) [GM (GSD)]: 0.96 (1.6)-1.42 (1.4) ng kg(-1)d(-1)). The dietary intakes of endosulfan in Seoul as GM (GSD) were 38.68 (1.3) ng kg bw(-1)d(-1) in 1994 and 92.17 (4.4) ng kg bw(-1)d(-1) in 2007, and significantly higher than those in Japan (p<0.05). The samples from Beijing showed a 50-fold increase in the endosulfan levels from 1993 (GM: 0.58 ng kg(-1)d(-1)) to 2009 (GM: 24.91 ng kg bw(-1)d(-1)) (p<0.05). Toxaphene was detected in 33 of 40 samples from Japan. The dietary intake of toxaphene in Japan (sum of Parlars #26, #50 and #62) was 0.32-1.21 ng kg bw(-1)d(-1) (range as geometric mean) and no temporal trend was observed. The dietary intake of toxaphene in Seoul increased significantly from 0.2 ng kg bw(-1)d(-1) (GM) in 1994 to 3.6 ng kg bw(-1)d(-1) (GM) in 2007 (p<0.05). Only one of 10 pooled samples from Beijing contained a detectable level of toxaphene (0.3 ng kg bw(-1)d(-1)). For the entire population, the risk of adverse health effects from dietary intakes of endosulfan and toxaphene is unlikely. However, the concentrations of endosulfan in several samples exceeded 10% of the acceptable daily intake limit value of 6 µg kg bw(-1)d(-1) set by the World Health Organization (WHO). It appears important to refine dietary intake estimates targeting food types and source identification to ensure safe food for consumers.

A comparative study of adsorption of perfluorooctane sulfonate (PFOS) onto granular activated carbon, ion-exchange polymers and non-ion-exchange polymers.

Perfluorooctane sulfonate (PFOS) is the latest chemical categorized as persistent organic pollutants (POPs). PFOS appears in the environmental water and tap water in ng L(-1) level. The process of adsorption has been identified as an effective technique to eliminate PFOS in water. Three non-ion-exchange polymers (DowV493, DowL493 and AmbXAD4), two ion-exchange polymers (DowMarathonA and AmbIRA400) and one granular activated carbon (GAC) (Filtersorb400) were tested with regard to their sorption kinetics and isotherms at low PFOS concentrations (100-1000 ng L(-1) equilibrium concentrations). The sorption capacities at 1 microg L(-1) equilibrium concentration decreased in the following order: ion-exchange polymers>non-ion-exchange polymers > GAC, but at further low equilibrium concentration (100 ng L(-1)) non-ion-exchange polymers showed higher adsorption capacity than other adsorbents. In the case of sorption kinetics, GAC and ion-exchange polymers reached the equilibrium concentration within 4 h and AmbXAD4 within 10 h. DowV493 and DowL493 took more than 80 h to reach equilibrium concentration. AmbIRA400 was identified as the best filter material to eliminate PFOS at equilibrium concentration > 1000 ng L(-1). Considering both adsorption isotherms and adsorption kinetics, AmbXAD4 and DowMarathonA were recommended to eliminate PFOS at ng L(-1) equilibrium concentration.