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Most Cited Emerging Contaminants Articles

The most cited articles published since 2015, extracted from Scopus.

Occurrence, sources and fate of pharmaceuticals and personal care products in the groundwater: A review

© 2015 The Authors The presence of pharmaceuticals and personal care products (PPCPs) in the aquatic environment may pose potential threat to the ecosystem and human health, hence PPCPs have aroused much concern over the world. The contamination of PPCPs in the groundwater, the main source of drinking water supply in many countries and regions, has been extensively studied in the last decade. This paper reviews the occurrence of frequently detected PPCPs, including antibiotics, anti-inflammatories, lipid-regulators, carbamazepine, caffeine, and N,N-diethyl-m-toluamide in groundwater, with special concern to the progress made over the past three years. Possible emission sources for PPCPs in groundwater, such as wastewater and contaminated surface water, landfills, septic systems, livestock breeding and sewer leakage, are summarized. Besides, adsorption, migration and degradation, the dominant mechanisms in the subsurface transport and fate of PPCPs, are discussed, and the insights into the future study of PPCPs in the groundwater are provided.

Pharmaceuticals and personal care products (PPCPs) in the freshwater aquatic environment

Volume 3, Issue 1, March 2017, Pages 1-16
Anekwe Jennifer Ebele | Mohamed Abou-Elwafa Abdallah | Mohamed Abou-Elwafa Abdallah | Stuart Harrad

© 2017 KeAi Communications Co., Ltd Pharmaceuticals and personal care products (PPCPs) are a unique group of emerging environmental contaminants, due to their inherent ability to induce physiological effects in human at low doses. An increasing number of studies has confirmed the presence of various PPCPs in different environmental compartments, which raises concerns about the potential adverse effects to humans and wildlife. Therefore, this article reviews the current state-of-knowledge on PPCPs in the freshwater aquatic environment. The environmental risk posed by these contaminants is evaluated in light of the persistence, bioaccumulation and toxicity criteria. Available literature on the sources, transport and degradation of PPCPs in the aquatic environment are evaluated, followed by a comprehensive review of the reported concentrations of different PPCP groups in the freshwater aquatic environment (water, sediment and biota) of the five continents. Finally, future perspectives for research on PPCPs in the freshwater aquatic environment are discussed in light of the identified research gaps in current knowledge.

Polybrominated diphenyl ethers and “novel” brominated flame retardants in floor and elevated surface house dust from Iraq: Implications for human exposure assessment

Volume 2, Issue 1, March 2016, Pages 7-13
Layla Salih Al-Omran | Layla Salih Al-Omran | Stuart Harrad

© 2015 The Authors Concentrations of polybrominated diphenyl ethers (PBDEs) and selected novel brominated flame retardants (NBFRs) were measured in indoor dust from the living areas of 18 homes in Basrah, Iraq. This is the first report of contamination of the Iraqi environment with these chemicals. To evaluate the implications for human exposure, samples were collected from both the floor and from elevated surfaces like tables, shelves and chairs. When normalised for the organic carbon content of the dust sample, concentrations in elevated surface dust of BDE-99, BDE-209, pentabromoethylbenzene (PBEB), bis (2-ethylhexyl) 3,4,5,6-tetrabromophthalate (BEH-TEBP), and decabromodiphenylethane (DBDPE) exceeded significantly (p < 0.05) those in floor dust from the same rooms. This suggests that previous studies that base estimates of adult exposure via dust ingestion on floor dust, may underestimate exposure. Such underestimation is less likely for toddlers who are far more likely to ingest floor dust. Concentrations of PBDEs and NBFRs in indoor dust from Basrah, Iraq are at the lower end of levels reported elsewhere. The PBDE contamination pattern in our samples suggests that use in Iraq of the Deca-BDE formulation, exceeds substantially that of Penta-BDE, but that use of the Octa-BDE formulation has been higher in Iraq than in some other regions. Reassuringly, our estimates of exposure to our target BFRs via dust ingestion for the Iraqi population fall well below the relevant health-based limit values.

Sampling strategy for estimating human exposure pathways to consumer chemicals

© 2016 The Authors Human exposure to consumer chemicals has become a worldwide concern. In this work, a comprehensive sampling strategy is presented, to our knowledge being the first to study all relevant exposure pathways in a single cohort using multiple methods for assessment of exposure from each exposure pathway. The selected groups of chemicals to be studied are consumer chemicals whose production and use are currently in a state of transition and are; per- and polyfluorinated alkyl substances (PFASs), traditional and “emerging” brominated flame retardants (BFRs and EBFRs), organophosphate esters (OPEs) and phthalate esters (PEs). Information about human exposure to these contaminants is needed due to existing data gaps on human exposure intakes from multiple exposure pathways and relationships between internal and external exposure. Indoor environment, food and biological samples were collected from 61 participants and their households in the Oslo area (Norway) on two consecutive days, during winter 2013-14. Air, dust, hand wipes, and duplicate diet (food and drink) samples were collected as indicators of external exposure, and blood, urine, blood spots, hair, nails and saliva as indicators of internal exposure. A food diary, food frequency questionnaire (FFQ) and indoor environment questionnaire were also implemented. Approximately 2000 samples were collected in total and participant views on their experiences of this campaign were collected via questionnaire. While 91% of our participants were positive about future participation in a similar project, some tasks were viewed as problematic. Completing the food diary and collection of duplicate food/drink portions were the tasks most frequent reported as “hard”/”very hard”. Nevertheless, a strong positive correlation between the reported total mass of food/drinks in the food record and the total weight of the food/drinks in the collection bottles was observed, being an indication of accurate performance of the participants despite the challenges of the sampling campaign.

Occurrence of emerging flame retardants from e-waste recycling activities in the northern part of Vietnam

© 2015 The Authors This study investigated the contamination status of 21 emerging flame retardants (FRs) in soils (n = 32) and river sediments (n = 8) from an e-waste recycling (EWR) site in the northern part of Vietnam. Among analyzed FRs, higher levels of decabromodiphenyl ethane (DBDPE) (ND–4200 ng/g dw), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE) (ND–350 ng/g dw) and Dechlorane Plus isomers (DPs) (ND–65 ng/g dw) were found in soils near EWR workshops and open burning places. The highest concentrations of DBDPE (20 ng/g dw), BTBPE (5.7 ng/g dw) and DPs (6.7 ng/g dw) were also detected in sediments collected from the middle of the EWR site. The levels decreased concomitantly with increasing distance from the EWR site. These results indicate that these FRs were released to the surrounding environment from improper recycling activities, such as manual dismantling of devices and open burning of e-wastes. Moreover, the estimated daily intakes of those FRs via soil ingestion were approximately ten times higher for children than adults. To our knowledge, this is a first comprehensive study on characterization of soil and sediment contamination by a series of emerging FRs at an EWR site in Vietnam.

Assessing the persistence of pharmaceuticals in the aquatic environment: Challenges and needs

© 2016 KeAi Communications Co., Ltd Chemical's persistence is known to be an important parameter applied for decades to identify persistent organic pollutants in hazard and/or risk assessments. Nevertheless it is greatly challenged in the case of emerging contaminants such as pharmaceuticals because the persistence of these chemicals could be more affected by environmental conditions. This fact brings more challenges to the current system for evaluating the persistence of chemical contaminants. In this paper, challenges in assessing the persistence of pharmaceuticals were identified, and more importantly research needs were addressed based on the existing data and knowledge.

A review of the role of emerging environmental contaminants in the development of breast cancer in women

Volume 2, Issue 4, December 2016, Pages 204-219
Shabana Siddique | Cariton Kubwabo | Shelley A. Harris | Shelley A. Harris | Shelley A. Harris

© 2016 KeAi Communications Co., Ltd The incidence of breast cancer is on a rise worldwide; it is a disease having a complex etiology. Besides genetics, environmental and other lifestyle factors play a role in the development of the disease. There has been a keen interest in studying associations between breast cancer and exposures to emerging environmental chemicals, which mimic estrogens or influence estrogen levels and signaling in the human body. The common consequence of an endocrine disrupting chemical exposure is that it may have an impact on breast cancer etiology by stimulating formation as well as progression of breast cancer. Exposures to selected emerging environmental contaminants such as alkylphenols (APs), bisphenol A (BPA), parabens, perfluoroalkyl substances (PFASs), phthalates, polybrominated diphenyl ethers (PBDEs), synthetic musks and triclosan, and their probable role in breast cancer development are reviewed. Studies evaluated include the experimental in vitro and in vivo studies as well as human population based studies. In vitro and in vivo evidences indicate that a number of emerging environmental contaminants may play a role in the initiation and/or progression of breast cancer. Although exposures have been assessed in some human populations, breast and other cancer risks associated with these exposures are largely unknown. Efforts should be focussed on the evaluation of these environmental exposures in human populations and their interactions with each other and other genetic and lifestyle risk factors.

Defluoridation of groundwater by calcined Mg/Al layered double hydroxide

© 2016 The Authors The present study evaluated calcined Mg/Al layered double hydroxide (CLDH) availability for the removal of fluoride from local groundwaters. The Mg/Al layered double hydroxide (LDH) was synthesized by co-precipitation method and characterized by XRD, FT-IR and TGA-TDA analyses. Batch defluoridation experiments were performed under various conditions such as calcination, solution pH, contact time, temperature, material dosage and reuse. Experimental results indicate that fluoride removal strongly increased after calcination of the LDH up to 600 °C. The maximum fluoride removal was obtained at solution pH of 6.85. Kinetics of fluoride removal followed the pseudo-second order kinetic model. The rise in solution temperature strongly enhances the removal efficiency. The adsorption mechanism involved surface adsorption, ion exchange interaction and original LDH structure reconstruction by rehydration of mixed metal oxides and concomitant intercalation of fluoride ions into the interlayer region. The optimum dosages required to meet the national standard for drinking water quality were found to be 0.29 and 0.8 g/L, respectively, for Bejaad and Settat goundwaters. A decrease in the fluoride uptake with increasing the number of regeneration cycles was observed.

Analysis of monomeric and oligomeric organophosphorus flame retardants in fish muscle tissues using liquid chromatography–electrospray ionization tandem mass spectrometry: Application to Nile tilapia (Oreochromis niloticus) from an e-waste processing area in northern Vietnam

© 2016 The Authors Using electrospray ionization tandem mass spectrometry combined with liquid chromatography (LC), a novel analytical method was developed to quantify eight monomeric organophosphorus flame retardants (m-PFRs) and three oligomeric organophosphorus flame retardants (o-PFRs) in fish muscle samples. The optimization and validation experiments indicate that the developed method can determine accurately the concentrations of analytes in fish muscle samples. The recoveries of analytes in fish muscle samples were in the range of 74–105%. The coefficients of variation of the concentrations of analytes in fish muscle samples were 0.6–8.9%. The concentrations of analytes in procedural blanks were below the limit of quantification (LOQ) values. Furthermore, the developed method was applied to the analysis of m-PFRs and o-PFRs in the muscle samples of tilapias collected from an electronic waste (e-waste) processing area in northern Vietnam. The concentrations of m-PFRs such as tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), and triphenyl phosphate (TPHP) were dominant among the investigated m-PFRs. The respective concentrations of TCEP, TCIPP, and TPHP were up to 160, 300, and 230 ng g−1lipid weight, respectively, whereas those of o-PFRs were up to 10 ng g−1lipid weight. The results of this study indicate lower accumulation potential of o-PFRs compared with m-PFRs for the first time.

Use of wild trout for PBDE assessment in freshwater environments: Review and summary of critical factors

© 2015 The Authors Certain wild animals represent sentinels to address issues related to environmental pollution, since they can provide integrative data on both pollutant exposure and biological effects. Despite their technological benefits, PBDEs are considered a threat to environmental health due to their persistence, toxicity, and capacity to be accumulated. These pollutants have been found geographically widespread in fish, particularly in predator species such as trout. The aim of this work is to critically review the applicability and usefulness of wild trout for assessing PBDEs in freshwater environments. Reviewed reports include data from highly industrialized areas as well as areas from remote regions with relatively low human activity, including European and North American great lakes and freshwater environments in Europe, Greenland, subarctic areas and Patagonia, respectively. A summary of relevant factors were grouped into organism-specific factors (food habits, age, size, lipid content, sex and reproduction, tissue type, mechanism of contaminant uptake and metabolism), and PBDE levels in the surrounding environment (sediment). Five wild trout species [rainbow trout (Oncorhynchus mykiss), brown trout (Salmo trutta), lake trout (Salvelinus namaycush), arctic char (Salvelinus alpinus), and brook trout (Salvelinus fontinalis)], collected worldwide within the 1994 to present time frame, were considered. Multivariate techniques (principal component analysis-PCA) and mapping approach, showed clear differences in geographic distribution patterns of PBDE levels in trout depending on the region studied: wild trout from European and North American great lakes have the highest PBDE loads. This pattern could be due to high industrial activity at these locations. A correlational approach used to explore intraspecific relationships between PBDE levels and morphometry, showed positive relationships only for brown trout. Further, brown trout showed the highest trout-to-sediment ratios, which is suggestive of a relatively greater capacity of this species to accumulate PBDEs in relation to sediment levels. Overall, results suggest that adult wild trout could be useful as a PBDE bioindicator.

Detection of novel brominated flame retardants (NBFRs) in the urban soils of Melbourne, Australia

Volume 3, Issue 1, March 2017, Pages 23-31
Thomas J. McGrath | Paul D. Morrison | Paul D. Morrison | Andrew S. Ball | Bradley O. Clarke

© 2017 The Authors A range of brominated flame retardants (BFRs) have been incorporated into polymeric materials like plastics, electronic equipment, foams and textiles to prevent fires. The most common of these, polybrominated diphenyl ethers (PBDEs), have been subject to legislated bans and voluntary withdrawal by manufacturers in North America, Europe and Australia over the past decade due to long-range atmospheric transport, persistence in the environment, and toxicity. Evidence has shown that replacement novel brominated flame retardants (NBFRs) are released to the environment by the same mechanisms as PBDEs and share similar hazardous properties. The objective of the current research was to characterize soil contamination by NBFRs in the urban soils of Melbourne, Australia. A variety of industrial and non-industrial land-uses were investigated with the secondary objective of determining likely point sources of pollution. Six NBFRs; pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), hexabromobenzene (HBB), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenyl ethane (DBDPE) were measured in 30 soil samples using selective pressurized liquid extraction (S-PLE) and gas chromatography coupled to triple quadrupole mass spectrometry (GC-MS/MS). NBFRs were detected in 24/30 soil samples with Σ5NBFR concentrations ranging from nd-385 ng/g dw. HBB was the most frequently detected compound (14/30), while the highest concentrations were observed for DBDPE, followed by BTBPE. Electronic waste recycling and polymer manufacturing appear to be key contributors to NBFR soil contamination in the city of Melbourne. A significant positive correlation between Σ8PBDEs and Σ5NBFR soil concentrations was observed at waste disposal sites to suggest that both BFR classes are present in Melbourne's waste streams, while no association was determined among manufacturing sites. This research provides the first account of NBFRs in Australian soils and indicates that these emerging contaminants possess a similar potential to contaminate Melbourne soils as PBDEs.

Concentrations of organophosphate flame retardants in dust from cars, homes, and offices: An international comparison

Volume 2, Issue 2, June 2016, Pages 66-72
Stuart Harrad | Sandra Brommer | Jochen F. Mueller

© 2016 The Authors Concentrations of a number of organophosphate flame retardants (PFRs) were measured in floor dust collected from living rooms in Australia (n = 42), Canada (n = 14), Germany (n = 22), and Kazakhstan (n = 9); cars from Australia (n = 39) and Germany (n = 19); and offices from Germany (n = 25) and Kazahkstan (n = 8). PFR concentrations in these samples were compared with each other and with previously reported data for PFRs in dust from similar microenvironments in the UK. Our data reveal significant between-country differences in both absolute concentrations and the relative abundance of specific PFRs in each of the microenvironments studied. Most notably, concentrations of TCIPP in UK living room dust (median = 21 μg g−1) exceeded significantly (p < 0.05) those in all other countries studied here; a substantial number of car dust samples contained elevated concentrations of TDCIPP, and German samples generally contained lower levels of PFRs in all microenvironments studied. In addition, PFRs were determined in dust samples collected from living room couches in both Australia (n = 41) and the UK (n = 10). The elevated concentrations of TCIPP in UK living room dust are likely attributable to the favoured use of this PFR in UK couch foam. This is indicated by concentrations of TCIPP in UK couch dust (median = 610 μg g−1) exceeding significantly those in Australian couch dust (median = 2.9 μg g−1). Moreover, concentrations of TCIPP in UK couch dust originating from couches 15 years old or less, display a marked relationship with the age of the couch, with concentrations in such samples increasing significantly (p < 0.01) with couch age.

Comprehensive evaluation of dioxins and dioxin-like compounds in surface soils and river sediments from e-waste-processing sites in a village in northern Vietnam: Heading towards the environmentally sound management of e-waste

© 2016 The Authors The management of electronic waste (e-waste), which can be a source of both useful materials and toxic substances, depending on the processing method, is important for promoting material cycling. In this study, we used the dioxin-responsive chemical-activated luciferase gene expression (DR-CALUX) assay combined with gas chromatography–high-resolution mass spectrometry to evaluate the levels of dioxin-like compounds in surface soils and river sediments collected in and around an e-waste-processing village in northern Vietnam. The WHO-TEQs (Toxic equivalents) of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), coplanar polychlorinated biphenyls (Co-PCBs), and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) in soils collected in January 2012 ranged from 0.29 to 310 pg/g (median 2.9 pg/g, n = 32), and the WHO-TEQs in sediments ranged from 0.96 to 58 pg/g (median 4.4 pg/g, n = 8). Dioxin-like activities (CALUX-TEQs [2,3,7,8-TCDD equivalent]) in soils collected in January 2012, 2013, and 2014 ranged from <30 to 4300 pg/g (median <30 pg/g, n = 96), and the activities in sediments ranged from <30 to 4000 pg/g (median 33 pg/g, n = 24). Dioxin-like compounds accumulated in samples collected around e-waste-processing areas such as open-burning sites and e-waste-processing workshops, and the compounds may be transported from their sources to surrounding areas over the course of several years. Some of the CALUX-TEQs, but not WHO-TEQs, values were higher than the maximum acceptable WHO-TEQs promulgated by various authorities, indicating that all dioxin-like compounds should be evaluated in samples collected from e-waste-processing areas. Our findings suggest that open burning and open storage of e-waste should be prohibited and that wastewater treatment should be implemented at each workshop to reduce contamination by dioxin-like compounds from e-waste.

Occurrence of pharmaceuticals and perfluorinated compounds and evaluation of the availability of reclaimed water in Kinmen

Volume 2, Issue 3, September 2016, Pages 135-144
Webber Wei Po Lai | Yen Ching Lin | Hsin Hsin Tung | Shang Lien Lo | Angela Yu Chen Lin

© 2016 The Authors Emerging contaminants have commonly been observed in environmental waters but have not been included in water quality assessments at many locations around the world. To evaluate the availability of reclaimed water in Kinmen, Taiwan, this study provides the first survey of the distribution of thirty-three pharmaceuticals and five perfluorinated chemicals in lake waters and water from local wastewater treatment plants (WWTPs). The results showed that the target emerging contaminants in Kinmen lakes were at trace ng/L concentrations. In addition, most of the target compounds were present in the Jincheng and Taihu WWTP influents at ng/L concentrations levels, of which 5 compounds (erythromycin-H2O (1340 ng/L), ibuprofen (1763 ng/L), atenolol (1634 ng/L), acetaminophen (2143 ng/L), and caffeine (3113 ng/L)) reached μg/L concentrations. The overall treatment efficiencies of the Jincheng and Taihu WWTPs with respect to these pharmaceuticals and perfluorinated chemicals were poor; half of the compounds were less than 50% removed. Five compounds (sulfamethoxazole, erythromycin-H2O, clarithromycin, ciprofloxacin and ofloxacin) with risk quotient (RQ) values > 1 in the effluent should be further investigated to understand their effects on the aquatic environment. Additional and advanced treatment units are found necessary to provide high-quality recycled water and sustainable water resources.

An insight of environmental contamination of arsenic on animal health

Volume 3, Issue 1, March 2017, Pages 17-22
Paramita Mandal

© 2017 KeAi Communications Co., Ltd The main threats to human health from heavy metals are associated with exposure to lead, cadmium, mercury and arsenic. Exposure to arsenic is mainly via intake of food and drinking water, food being the most important source in most populations. Although adverse health effects of heavy metals have been known for a long time, exposure to heavy metals continues and is even increasing in some areas. Long-term exposure to arsenic in drinking-water is mainly related to increased risks of skin cancer, but also some other cancers, as well as other skin lesions such as hyperkeratosis and pigmentation changes. Therefore, measures should be taken to reduce arsenic exposure in the general population in order to minimize the risk of adverse health effects. Animal are being exposed to arsenic through contaminated drinking water, feedstuff, grasses, vegetables and different leaves. Arsenic has been the most common causes of inorganic chemical poisoning in farm animals. Although, sub-chronic and chronic exposure of arsenic do not generally reveal external signs or symptoms in farm animals but arsenic (or metabolites) concentrations in blood, hair, hoofs and urine are remained high in animals of arsenic contaminated zones. So it is assumed that concentration of arsenic in blood, urine, hair or milk have been used as biomarkers of arsenic exposure in field animals.

Early life exposure to per- and polyfluoroalkyl substances (PFASs): A critical review

Volume 3, Issue 2, June 2017, Pages 55-68
Kerstin Winkens | Robin Vestergren | Robin Vestergren | Urs Berger | Ian T. Cousins

© 2017 The Authors Due to the dynamic developmental processes during pregnancy, infancy, childhood and adolescence, exposure to PFASs is hypothesized to have the most pronounced negative effects during this period. In this review we critically evaluate the current state of the science regarding human early life exposure processes (until 18 years of age) to per- and polyfluoroalkyl substances (PFASs). Efficient placental transfer of perfluoroalkyl acids (PFAAs) results in relatively high prenatal exposure compared with many neutral organic contaminants. The few biomonitoring studies that specifically target infants, toddlers and other children suggest relatively high serum concentrations of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in early life with peak concentrations occurring sometime before the child reaches 20 months. This peak in serum concentrations is most likely explained by exposure via breastfeeding, ingestion of house dust and/or specific contact events with consumer products leading to high body weight normalized estimated daily intakes (EDIs). Although children have higher EDIs of PFASs than adults, these are not always reflected by higher serum levels of PFASs in children in cross-sectional biomonitoring studies due to the confounding effect of age and birth cohort, and different exposure histories due to production changes. Longitudinal exposure studies measuring internal and external exposure (for multiple pathways and PFASs) at several time points during early life are strongly encouraged to understand temporal changes in exposure of individual children. A better quantitative understanding of early life exposure processes would help to improve the validity of epidemiological studies and allow informed decisions regarding setting of regulatory thresholds and appropriate mitigation actions.

Localization of polycyclic aromatic hydrocarbons and heavy metals in surface soil of Asia's oldest oil and gas drilling site in Assam, north-east India: Implications for the bio-economy

Volume 2, Issue 3, September 2016, Pages 119-127
Hemen Sarma | N. F. Islam | P. Borgohain | A. Sarma | M. N.V. Prasad

© 2016 KeAi Communications Co., Ltd The environmental influx of hazardous contaminants viz PAHs and HMs occurs due to oil and gas drilling, and processing of petroleum products in industrial facilities and refineries. This problem plagues crude oil drilling sites as PAHs are an essential component of and HMs coexist with crude oil. We analyzed the spatial distribution of 16 PAHs and 8 HMs in 10 contaminated sites of Assam, a state in India. These included Digboi, where crude oil was drilled in 1867 and the first oil well in Asia that was drilled. The Ʃ16 PAHs in soil were detected with a minimum of 13.48 and a maximum of 86.3 mgkg−1and Ʃ 8 heavy metal concentrations in the soil ranged between 69.51 and 336.06 mgkg−1. A negative correlation was detected between the relative concentrations of PAHs and HMs. The results confirmed that the non-biodegradable nature of HMs made them stay in the soil for longer periods of time. In our study, we found that the levels of lead, copper, nickel, and chromium (total) in soil were 73.62, 11.86, 58.97 and 158.66 mgkg−1. The recovery percentage for PAHs and HMs were in the range of 67–97% and 90–95% respectively. Spatial distribution indices for Phenanthrene/Anthracene, Naphthalene/Acenapthhylene, Chyrsene/Benzo (g, h, i) perylene and Fluranthene/Pyrene) calculated for soil samples indicated that the spatial distribution of PAHs in soil is uneven which might be due to variations in contaminates disseminated in soil. Such regionalized concentration has serious implications on the bio-economy both in terms of health and economy, especially since the proximity of crude oil sites to paddy fields and/or tea plantations uniquely marks the landscape of upper Assam.

Hexabromocyclododecane and tetrabromobisphenol-A in indoor dust from France, Kazakhstan and Nigeria: Implications for human exposure

© 2016 The Authors Concentrations of hexabromocyclododecane isomers (α-, β- and γ-HBCDs) and tetrabromobisphenol-A (TBBP-A) were measured – for the first time – in indoor dust from homes, offices and cars from France, Kazakhstan and Nigeria. ΣHBCDs in French and Kazakhstani house dust (median = 1351 and 280 ng g−1, respectively) were consistent with previous reports from the UK and Romania, respectively. Concentrations of ΣHBCDs in Nigerian domestic dust (median = 394 ng g−1) were substantially higher than those reported from Egyptian homes. In general, concentrations of ΣHBCDs in the studied microenvironments were higher than those of TBBP-A, which may be attributed to the major application of TBBP-A as a reactive flame retardant; rendering its release to dust more difficult. Statistical analysis revealed significantly lower ΣHBCDs in French houses than those found in both offices and cars, while ΣHBCDs in cars from Kazakhstan were higher (P < 0.05) than those in homes and offices. Moreover, TBBP-A concentrations in car dust from Nigeria were lower than those found in homes and offices. Exposure estimates revealed higher intake of HBCDs and TBBP-A by toddlers via indoor dust ingestion compared to adults. Combined with their low body weight, this can raise concerns over the potential adverse health effects of such high exposure in toddlers.

Highly efficient removal of perfluorooctanoic acid from aqueous solution by H2O2-enhanced electrocoagulation-electroflotation technique

© 2016 The Authors Electrocoagulation (EC) technique was used to investigate the removal performance of aqueous perfluorooctanoic acid (PFOA) with relatively high concentration as simulating the wastewater from organic fluorine industry. A comparison was done with the similar amount of coagulant between EC and chemical coagulation process. PFOA removal obtained was higher with EC process, especially for Fe anode. Several factors were studied to optimize the EC process. At the optimal operating parameters including 37.5 mA/cm2of current density, initial pH 3.77, and 180 rpm of mixing speed, 93% of PFOA could be removed with 100 mg/L of initial concentration after 90-min electrolysis. Furthermore, the remove efficiency could be obviously improved by H2O2intermittent addition, which removed more than 99% of PFOA within 40-min EC. It could be attributed to that H2O2facilitated the oxidative transformation from ferrous to ferric ion. In addition, the adsorptive removal of aqueous PFOA on Fe flocs during EC was also verified by fourier transform infrared spectra.

Pay special attention to the transformation products of PPCPs in environment

© 2017 KeAi Communications Co., Ltd Pharmaceuticals and personal care products (PPCPs) have received increasing attention. However, their transformation products (TPs) and metabolites, sometimes even with environmental concentration and/or toxicity higher than their parent compounds, received attention far from enough. This study gives useful insight on the occurrence, fate and toxicity of PPCP TPs or metabolites in WWTPs, surface water and even drinking water, highlighting the necessity of studying the PPCP TPs formation, occurrence, toxicity and environment risk, and further evaluating the environmental risk caused by PPCPs comprehensively.

Integrative assessment of biomarker responses in teleostean fishes exposed to glyphosate-based herbicide (Excel Mera 71)

© 2016 KeAi Communications Co., Ltd Present study deals with the effects of glyphosate-based herbicide, Excel Mera 71 on Anabas testudineus, Heteropnestes fossilis and Oreochromis niloticus in field conditions (1.85 kg/ha) based on anti-oxidative, metabolic and digestive responses. For this study following biomarkers viz., acetylcholinesterase (AChE), lipid peroxidation (LPO), catalase (CAT), glutathione-S-transferase (GST), alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), amylase, lipase and protease were investigated in gill, stomach, intestine, liver, kidney, brain, muscle and spinal cord of the concerned fish species. Enzyme activities were significantly altered by glyphosate exposure after 30 days, these activities were tissue as well as species specific. The results suggested that these biomarkers could be used to assess the ecological risks of glyphosate on fish. Bioaccumulation factor (BAF) studied in different aquatic natural macrophytes showed order of Alternanthera philoxeroides > Azolla pinnata > Lemna sp. (Minor) > Lemna sp. (Major) > Pistia stratiotes, while transfer factor (TF) showed the order of Pistia stratiotes > Alternanthera philoxeroides > Lemna sp. Bioconcentration factor (BCF) study showed maximum accumulation of glyphosate in liver, kidney or intestine, and minimum either in bone or stomach irrespective of fish species. An integrated biomarker response (IBR), which uses a battery of biomarkers to calculate the standardized scores for each biomarker responses ranging from physiological to biochemical/molecular responses, was evaluated by combining the multiple biomarkers into a single value to evaluate quantitatively the toxicological effects of glyphosate. In general, the multiple indices exhibited variations and A. testudineus was more affected than other fish species; maximum IBR value was observed for LPO and minimum in case of ALT. The order of integrated biomarkers caused by glyphosate treatment was recorded as follows: LPO > Amylase > CAT > AST > Protease > Lipase > ALP > GST > AChE > ALT for A. testudineus, LPO > AChE > AST > Protease > CAT > Amylase > Lipase > GST > ALP > ALT for H. fossilis and AChE > CAT > LPO > AST > Amylase > GST > Protease > ALP > Lipase > ALT for O. niloticus. Finally, IBR analysis is able to distinguish the variations between different parameters and might be a useful tool for the quantification of integrated responses induced by glyphosate toward fish.

A meta-analysis of recent data on UK environmental levels of POP-BFRs in an international context: Temporal trends and an environmental budget

Volume 1, Issue 1, November 2015, Pages 39-53
Stuart Harrad

© 2015 The Author This study collates and synthesises UK data on environmental levels of POP-BFRs published between 1999 and March 2015. Target POP-BFRs are: the polybrominated diphenyl ether (PBDE) formulations Penta-BDE, Octa-BDE, and Deca-BDE (the latter as a candidate Stockholm Convention POP), as well as hexabromocyclododecane (HBCDD). Environmental compartments covered include: sediments (freshwater and marine), atmospheric deposition (both measured directly and inferred from sediment core data), soil, herbage, outdoor air, indoor air, indoor dust, freshwater (rivers and lakes), human tissues (blood serum and milk), wildlife, and the human diet. Temporal trends in contamination were examined for evidence of environmental responses to regulatory and voluntary actions banning/restricting the manufacture and use of POP-BFRs. Good evidence exists that – with some exceptions – concentrations of Penta-BDE congeners like BDEs-47 and 99 have responded well to the use restrictions introduced in the mid-2000s. However, it appears that human body burdens of these contaminants do not appear to have responded in a similar way, as levels in UK human milk in 2010–2012, are not discernibly different to those reported in 2002–03. The evidence for HBCDD and BDEs-183 and 209 is less abundant, but signs exist that absolute concentrations of BDE-183 are falling in the UK environment. With respect to BDE-209, evidence from analysis of lake sediment core and UK diet samples, suggests that levels have yet to respond discernibly to the more recent curbs on manufacture and use of Deca-BDE. The limited evidence for HBCDD is strongly consistent with a declining trend in environmental contamination with this chemical. Broadly, examination of the UK database in an international context, suggests UK levels are generally within the range of those found in other industrialised countries. Interestingly, while UK concentrations of BDE-209 in abiotic matrices such as indoor dust, are at the high end of those reported globally; concentrations in UK human milk are amongst the lowest reported to date. This suggests that the bioavailability of BDE-209 from indoor dust is likely very low. An environmental budget was estimated for the UK burden of POP-BFRs. As with previous comparable exercises for polychlorinated biphenyls (PCBs) and chlorinated dioxins, the majority (>90%) of the UK burden of POP-BFRs resides in soil. Moreover, the POP-BFR burden identifiable as present in the UK environment is much lower than data on production and use of POP-BFRs in Europe. This may be explained by POP-BFRs: (a) undergoing environmental transport away from the UK; (b) undergoing environmental degradation; (c) remaining in use; and (d) entering the waste stream. While the UK database appears relatively strong for some environmental compartments and POP-BFRs – e.g. BDEs-47 and -99 are well-characterised in the human diet, indoor air/dust, and human milk – substantial gaps exist for BDE-209 and HBCDD in air (indoor and outdoor), herbage, and soil.

Mass transfer of an organophosphate flame retardant between product source and dust in direct contact

Volume 3, Issue 3, January 2017, Pages 115-120
Ioannis Liagkouridis | Borislav Lazarov | Georgios Giovanoulis | Ian T. Cousins

© 2017 KeAi Communications Co., Ltd Organophosphate flame retardants (OPFRs) are a group of semi-volatile organic compounds (SVOCs) and among the most abundant contaminants indoors. Their indoor presence has been associated with potential health risks however there is limited understanding as to how they are released from indoor sources. This study uses an emission micro-chamber to explore one of the currently understudied chemical migration pathways; direct transfer between a source material and settled dust in contact with the source. A tris(2-chloroisopropyl) phosphate (TCIPP)-treated insulation board is used as the source material. Rapid and substantial transfer was observed after only 8 h of source-dust contact, resulting in 80 times higher concentrations in dust compared to pre-experiment levels. Further time points at 24 h and 7 d showed similarly high average dust levels and the TCIPP in the dust and air in the chamber was calculated to be close to thermodynamic equilibrium. It was concluded that TCIPP was effectively transferred from the insulation board to the dust on its surface and the surrounding air via gas-phase diffusion. In a real room, a gradient of TCIPP concentrations in air above the surface of a product could result in higher concentrations in dust sitting on the product than dust in the rest of the room.

Inventory of primary emissions of selected persistent organic pollutants to the atmosphere in the area of Great Mendoza

© 2015 The Authors The setting up of a country or region-based inventory is considered a crucial step toward the elimination of worldwide persistent organic pollutants (POPs) contamination. Moreover, the need of comparable emission inventories at city or region level is widely recognized to develop evidence-based policies accounting for the relation between emissions and institutional, socio-economic and demographic characteristics at small scale level. Due to the low spatial and temporal resolution of the available measurements, highly variable air concentrations of several POPs have been observed in Latin American and Caribbean countries. This paper presents a high resolution spatially disaggregated atmospheric emission inventory for selected POPs in order to assess the environmental fate of some of these compounds in a finer resolution. As study case we estimated releases to air of POPs in a typical mid-size urban conglomeration in Argentina. Inventoried compounds were total polychlorinated biphenyls (PCBs), total polybrominated diphenyl ethers (PBDEs), total dichlorodiphenyltrichloroethane (DDT) on a sum basis, hexachlorobenzene (HCB) and dioxins and furans (PCDD/Fs), for which emissions were estimated in 0.92 kg/year, 1.65 kg/year, 4.2E−02 kg/year (total sum of congeners), 0.86 kg/year and 4.4E−02 kg/year respectively, values that are in accordance with the geographic and economic context. Although emitting sources are quite varied, there are very clear trends, particularly in relation to open burning of municipal solid waste and agrochemical use as major contributors. Overall, the inventory provides valuable data for the analysis of the heterogeneity of POP emissions and the necessary inputs for air quality modeling.

A comparative QSAR study on the estrogenic activities of persistent organic pollutants by PLS and SVM

Volume 1, Issue 1, November 2015, Pages 8-13
Fei Li | Jialin Liu | Lulu Cao

© 2015 The Authors Quantitative structure-activity relationships (QSARs) were determined using partial least square (PLS) and support vector machine (SVM). The predicted values by the final QSAR models were in good agreement with the corresponding experimental values. Chemical estrogenic activities are related to atomic properties (atomic Sanderson electronegativities, van der Waals volumes and polarizabilities). Comparison of the results obtained from two models, the SVM method exhibited better overall performances. Besides, three PLS models were constructed for some specific families based on their chemical structures. These predictive models should be useful to rapidly identify potential estrogenic endocrine disrupting chemicals.

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