A randomized clinical trial on the comparison between hair shaving and snipping prior to laser hair removal sessions in women suffering from hirsutism

Summary

Background and objectives

Hirsutism or excess hair growth is a common dermatological problem in females, affecting up to 10% of females worldwide. We aimed this study to compare the two hair-shortening methods shaving vs. snipping among hirsute women regarding the outcome of the therapy and also the paradoxical hypertrichosis phenomenon (terminal hair regrowth) 6 months after the final therapy session.

Materials and Methods

In this study, 129 premenopausal women affected by hirsutism were randomly divided into two study groups according to hair-shortening method: shaving as group A (66 patients) and hair shortening by scissor as group B (63 patients). Each patient received six alexandrite laser therapy sessions every month for six consecutive months. Chin hairs in a 5 × 5 cm² zone were counted, and the paradoxical hair regrowth was evaluated four times during the study: once at baseline, once before the third session, once before the sixth session, and once 6 months after the last laser session.

Results

Before the third session, the counts were 15.06 ± 5.20 in group A and 13.07 ± 4.44 in group B (P = 0.022); both counts were meaningfully less than the baseline count (P < 0.001). The counts before the sixth session were 2.80 ± 1.16 in group A and 2.71 ± 1.12 in group B (P = 0.673); the counts were significantly lower than the previous session (P < 0.001). Six months after the last laser session, the counts were 11.27 ± 9.30 in group A and 8.15 ± 3.12 in group B (P = 0.012). Paradoxical hypertrichosis was observed in three patients of group A vs. no patients in group B.

Conclusion

We found that alexandrite laser therapy is really effective for treating hirsutism. Both shaving and using a scissor for hair shortening showed similar short-term results, but in one-year follow-up, paradoxical hypertrichosis was only observed in shaving group and also a lower hair count was observed in the snipping group.

http://ift.tt/2c8RcVK

Comparison of skin properties in individuals living in cities at two different altitudes: an investigation of the environmental effect on skin

Summary

Background

Skin properties vary depending on exogenous factors. Various studies have been used for comparing skin properties between cities for studying environment influence on skin properties. However, for comparison of skin properties between cities, various environmental factors have to be considered.

Objectives

The purpose of this study therefore was to compare skin properties in individuals of the same ethnicity and sex (Indonesian women) between different altitudes and to interpret the environmental effect on skin.

Methods

In this study, we reanalyzed the data obtained from previous study. The data were for healthy Sundanese Indonesian females [(n = 136) at Jakarta (n = 49) and Bandung (n = 87)], and the data consisted of published data (skin hydration, sebum level, pH, elasticity, and transepidermal water loss) and unpublished data [skin color (L*, a*, and b*)]. The skin parameters were measured on Indonesian females aged 20–34 using C+K devices (corneometer, sebumeter, pH meter, and cutometer), Delfin vapometer, and Minolta spectrophotometer, respectively.

Results

Sundanese Jakarta (low-altitude) females had higher sebum level and greater redness (a*) value in the forehead than Sundanese Bandung (high-altitude) females. In contrast, Bandung females had higher skin pH, brighter skin color, and greater forehead skin elasticity than Jakarta females.

Conclusions

The skin properties can be influenced by changing altitude because different altitudes have different environments such as air temperature, humidity, UV radiation, and so on, and it is also necessary to investigate the factors which can influence with perceived skin condition such as skin type and skin concerning.

http://ift.tt/2co4CdT

Grasp-specific motor resonance is influenced by the visibility of the observed actor

Publication date: Available online 11 September 2016
Source:Cortex
Author(s): Karen L. Bunday, Roger N. Lemon, James M. Kilner, Marco Davare, Guy A. Orban
Motor resonance is the modulation of M1 corticospinal excitability induced by observation of others' actions. Recent brain imaging studies have revealed that viewing videos of grasping actions led to a differential activation of the ventral premotor cortex depending on whether the entire person is viewed vs. only their disembodied hand. Here we used transcranial magnetic stimulation (TMS) to examine motor evoked potentials (MEPs) in the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) during observation of videos or static images in which a whole person or merely the hand was seen reaching and grasping a peanut (precision grip) or an apple (whole hand grasp). Participants were presented with six visual conditions in which visual stimuli (video vs. static image), view (whole person vs. hand) and grasp (precision grip vs. whole hand grasp) were varied in a 2x2x2 factorial design. Observing videos, but not static images, of a hand grasping different objects resulted in a grasp-specific interaction, such that FDI and ADM MEPs were differentially modulated depending on the type of grasp being observed (precision grip vs. whole hand grasp). This interaction was present when observing the hand acting, but not when observing the whole person acting. Additional experiments revealed that these results were unlikely to be due to the relative size of the hand being observed. Our results suggest that observation of videos rather than static images is critical for motor resonance. Importantly, observing the whole person performing the action abolished the grasp-specific effect, which could be due to a variety of PMv inputs converging on M1.



http://ift.tt/2cQ7yUO

An image-invariant neural response to familiar faces in the human medial temporal lobe

Publication date: Available online 10 September 2016
Source:Cortex
Author(s): Katja Weibert, Richard J. Harris, Alexandra Mitchell, Hollie Byrne, Andrew W. Young, Timothy J. Andrews
The ability to recognize familiar faces with ease across different viewing conditions contrasts with the inherent difficulty in the perception of unfamiliar faces across similar image manipulations. Models of face processing suggest that this difference is based on the neural representation for familiar faces being more invariant to changes in the image, than it is for unfamiliar faces. Here, we used an fMR-adaptation paradigm to investigate neural correlates of image-invariant face recognition in face-selective regions of the human brain. Participants viewed faces presented in a blocked design. Each block contained different images of the same identity or different images from different identities. Faces in each block were either familiar or unfamiliar to the participants. First, we defined face-selective regions by comparing the response to faces with the response to scenes and scrambled faces. Next, we asked whether any of these face-selective regions showed image-invariant adaptation to the identity of a face. The core face-selective regions showed image-invariant adaptation to familiar and unfamiliar faces. However, there was no difference in the adaptation to familiar compared to unfamiliar faces. In contrast, image-invariant adaptation for familiar faces, but not for unfamiliar faces, was found in face-selective regions of the medial temporal lobe (MTL). Taken together, our results suggest that the marked differences in the perception of familiar and unfamiliar faces may depend critically on neural processes in the medial temporal lobe.



http://ift.tt/2cAKmrF

Augmenting Distractor Filtering via Transcranial Magnetic Stimulation of the Lateral Occipital Cortex

Publication date: Available online 10 September 2016
Source:Cortex
Author(s): Jana Eštočinová, Emanuele Lo Gerfo, Chiara Della Libera, Leonardo Chelazzi, Elisa Santandrea
Visual selective attention optimizes perception and behavioral control by enabling efficient selection of relevant information and filtering of distractors. While focusing resources on task-relevant information helps counteract distraction, dedicated filtering mechanisms have recently been demonstrated, allowing neural systems to implement suitable policies for the suppression of potential interference. Limited evidence is presently available concerning the neural underpinnings of these mechanisms, and whether neural circuitry within the visual cortex might play a causal role in their instantiation, a possibility that we directly tested here. In two related experiments, transcranial magnetic stimulation (TMS) was applied over the lateral occipital cortex of healthy humans at different times during the execution of a behavioral task which entailed varying levels of distractor interference and need for attentional engagement. While earlier TMS boosted target selection, stimulation within a restricted time epoch close to (and in the course of) stimulus presentation engendered selective enhancement of distractor suppression, by affecting the ongoing, reactive instantiation of attentional filtering mechanisms required by specific task conditions. The results attest to a causal role of mid-tier ventral visual areas in distractor filtering and offer insights into the mechanisms through which TMS may have affected ongoing neural activity in the stimulated tissue.



http://ift.tt/2cQ7PaD

Plastic Surgery and Suicide: A Clinical Guide for Plastic Surgeons

Summary: Several studies have identified an increased risk of suicide among patient populations which a plastic surgeon may have a high risk of encountering: women undergoing breast augmentation, cosmetic surgery patients, and breast cancer patients. No formal guidelines exist to assist a plastic surgeon when faced with such a patient, and not every plastic surgery team has mental health clinicians that are readily accessible for consultation or referral. The goal of this clinical guide is to offer plastic surgeons a set of practical approaches to manage potentially suicidal patients. In addition, the authors review a screening tool, which can assist surgeons when encountering high-risk patients.

http://ift.tt/2ciPAbG

Nipple Reconstruction with the Biodesign Nipple Reconstruction Cylinder: A Prospective Clinical Study

Background: Nipple reconstruction is the last stage in cosmetic reconstruction of the breast after mastectomy, but no method produces reliable and consistent aesthetic results. This study examined the use of the Biodesign Nipple Reconstruction Cylinder (NRC) during reconstruction of the nipple after mastectomy. Methods: Patients with a history of breast cancer and mastectomy desiring nipple reconstruction were invited to participate. After obtaining consent, unilateral or bilateral nipple reconstruction was performed. Skin flaps were raised, the NRC was placed beneath the flaps as a stent, and the site was protected for up to 4 weeks with a nipple shield. Nipple projection was measured for 12 months after surgery. Patient satisfaction was measured and adverse events were recorded. Follow-up examinations were performed at 1 week, and then at 1, 3, 6, and 12 months after surgery. Results: Eighty-two nipple reconstructions were performed in 50 patients. Related postoperative adverse events were minor, but reported in 8 reconstructions (9.8%) representing 7 patients (14.0%). Average projection at 6 and 12 months was 4.1 ± 1.6 mm and 3.8 ± 1.5 mm, respectively, compared with 10.5 ± 2.2 mm 1 week after surgery. Of patients completing the satisfaction questionnaire at 12 months, 70/75 (93.3%) of reconstructions were rated "pleased" or "very pleased" with the overall outcome. Overall, 45/46 (97.8%) patients would recommend nipple reconstruction to other women. Conclusions: The Biodesign NRC offers a safe alternative to nipple reconstruction, resulting in stable projection and a high level of patient satisfaction for 12 months after placement.

http://ift.tt/2ciOo8i

Understanding the Role for Operative Performance Rating Tools in Meeting Surgical Trainee Feedback Needs: A Qualitative Study

No abstract available

http://ift.tt/2cavHaa

Effect of non-surgical periodontal treatment by full-mouth disinfection or scaling and root planing per quadrant in halitosis—a randomized controlled clinical trial

Abstract

Objective

The objective of this study was to compare the effect of one-stage full-mouth disinfection (FMD) and conventional quadrant scaling in four weekly sessions (QS) on periodontal clinical parameters and halitosis among individuals with advanced chronic periodontitis.

Materials and methods

In this randomized controlled clinical trial, 30 individuals were divided into two groups: FMD (n = 15) and QS (n = 15). The following data were collected at the baseline and 90 days after treatment: plaque index, tongue-coating index (TCI), bleeding on probing, probing depth, and clinical attachment level. Halimetry was performed by the organoleptic method, and the levels of volatile sulfur compounds (H2S and CH3SH) were measured by gas chromatography. The Chi-square, Fisher's exact, the Mann-Whitney, the McNemar, and the Wilcoxon tests were used for statistical analysis.

Results

Both groups showed statistically significant improvements in periodontal clinical parameters, reduction in TCI, organoleptic scores, and in CH₃SH levels between times. However, major reduction was observed in FMD group.

Conclusion

Non-surgical periodontal therapy, regardless of the protocol, was effective in improving periodontal clinical status of individuals, decreasing organoleptic scores and CH₃SH levels between times, as well as reducing halitosis.

Clinical relevance

This study contributed to the knowledge that non-surgical periodontal therapy, whether by FMD or QS, was effective in reducing halitosis in individuals with advanced chronic periodontitis.

http://ift.tt/2cOmQLa

Effect of non-surgical periodontal treatment by full-mouth disinfection or scaling and root planing per quadrant in halitosis—a randomized controlled clinical trial

Abstract

Objective

The objective of this study was to compare the effect of one-stage full-mouth disinfection (FMD) and conventional quadrant scaling in four weekly sessions (QS) on periodontal clinical parameters and halitosis among individuals with advanced chronic periodontitis.

Materials and methods

In this randomized controlled clinical trial, 30 individuals were divided into two groups: FMD (n = 15) and QS (n = 15). The following data were collected at the baseline and 90 days after treatment: plaque index, tongue-coating index (TCI), bleeding on probing, probing depth, and clinical attachment level. Halimetry was performed by the organoleptic method, and the levels of volatile sulfur compounds (H2S and CH3SH) were measured by gas chromatography. The Chi-square, Fisher's exact, the Mann-Whitney, the McNemar, and the Wilcoxon tests were used for statistical analysis.

Results

Both groups showed statistically significant improvements in periodontal clinical parameters, reduction in TCI, organoleptic scores, and in CH₃SH levels between times. However, major reduction was observed in FMD group.

Conclusion

Non-surgical periodontal therapy, regardless of the protocol, was effective in improving periodontal clinical status of individuals, decreasing organoleptic scores and CH₃SH levels between times, as well as reducing halitosis.

Clinical relevance

This study contributed to the knowledge that non-surgical periodontal therapy, whether by FMD or QS, was effective in reducing halitosis in individuals with advanced chronic periodontitis.

http://ift.tt/2cOmQLa

In situ stabilization of heavy metals in multiple-metal contaminated paddy soil using different steel slag-based silicon fertilizer

Abstract

Steel slag has been widely used as amendment and silicon fertilizer to alleviate the mobility and bioavailability of heavy metals in soil. The objective of this study was to evaluate the influence of particle size, composition, and application rate of slag on metal immobilization in acidic soil, metals uptake by rice and rice growth. The results indicated that application of slag increased soil pH, plant-available silicon concentrations in soil, and decreased the bioavailability of metals compared with control treatment, whereas pulverous slag (S1) was more effective than granular slag (S2 and S3). The acid-extractable fraction of Cd in the spiked soil was significantly decreased with application of S1 at rates of 1 and 3 %, acid-extractable fractions of Cu and Zn were decreased when treated at 3 %. Use of S1 at both rates resulted in significantly lower Cd, Cu, and Zn concentrations in rice tissues than in controls by 82.6–92.9, 88.4–95.6, and 67.4–81.4 %, respectively. However, use of pulverous slag at 1 % significantly promotes rice growth, restricted rice growth when treated at 3 %. Thus, the results explained that reduced particle size and suitable application rate of slag could be beneficial to rice growth and metals stabilization.

http://ift.tt/2ctzIFU

Assessment of metal retention in newly constructed highway embankments

Abstract

Newly constructed embankments should provide both a specific bearing capacity to enable trafficability in emergency cases and a sufficient pollutant retention capacity to protect the groundwater. A number of lysimeters were installed along the A115 highway to determine total and dissolved metal concentrations in road runoff and in the soil solution of newly constructed embankments. Dissolved concentrations in soil solution of the embankments did not exceed the trigger values of the German legislation. Depending on the metal, total concentrations in soil solution were more than twice as high as dissolved concentrations. The high infiltration rates lead to increased groundwater recharge beneath the embankments (up to 4100 mm a⁻¹). Although metal concentrations were not problematic from the legislators' point of view, the elevated infiltration rates beside the road facilitated the transfer of high metal loads into deeper soil layers and potentially into the groundwater as well.

http://ift.tt/2cfVZDI

Heavy metal speciation, risk, and bioavailability in the sediments of rivers with different pollution sources and intensity

Abstract

A comprehensive analysis of heavy metal speciation, risk, and bioavailability in the sediments of three rivers in northern China (Shaocun River (SR), Wangyang River (WR), and Xiao River (XR)) was conducted. The results showed that higher pollution input resulting from urbanization and industrialization caused higher heavy metal contents and bioavailable proportion in the studied sediments. Total contents of all studied metals (Cr, Cu, Ni, Pb, and Zn) in the sediments of SR, WR, and XR were 270.31, 902.62, and 2367.46 mg/kg, respectively. The average percentages of bioavailable fractions were 31.16, 61.73, and 81.69 %, respectively. Cr, Ni, and Pb were all mainly observed in the B4 (residual) fraction in the studied sediments, with an average percentage of 42.03, 48.19, and 55.08 %, respectively. Cu was mainly observed in the B2 (reducible) fraction (40.53 %). Zn was mainly observed in the B1 (exchangeable/acid soluble/carbonate) fraction (36.01 %), resulting in medium or high risk associated with Zn in the sediments of SR, WR, and XR. Sedimentary heavy metal risk and bioavailability associated with regional urbanization and industrialization should be taken into consideration with respect to the health of aquatic ecosystems.

http://ift.tt/2ctAEKh

Assessment of trace metal air pollution in Paris using slurry-TXRF analysis on cemetery mosses

Abstract

Mosses are useful, ubiquitous accumulation biomonitors and as such can be used for biomonitoring surveys. However, the biomonitoring of atmospheric pollution can be compromised in urban contexts if the targeted biomonitors are regularly disturbed, irregularly distributed, or are difficult to access. Here, we test the hypothesis that cemeteries are appropriate moss sampling sites for the evaluation of air pollution in urban areas. We sampled mosses growing on gravestones in 21 urban and peri-urban cemeteries in the Paris metropolitan area. We focused on Grimmia pulvinata (Hedwig) Smith, a species abundantly found in all studied cemeteries and very common in Europe. The concentration of Al, As, Br, Ca, Ce, Cl, Cr, Cu, Fe, K, Mn, Ni, V, P, Pb, Rb, S, Sr, Ti, and Zn was determined by a total reflection X-ray fluorescence technique coupled with a slurry sampling method (slurry-TXRF). This method avoids a digestion step, reduces the risk of sample contamination, and works even at low sample quantities. Elemental markers of road traffic indicated that the highest polluted cemeteries were located near the highly frequented Parisian ring road and under the influence of prevailing winds. The sites with the lowest pollution were found not only in the peri-urban cemeteries, adjoining forest or farming landscapes, but also in the large and relatively wooded cemeteries located in the center of Paris. Our results suggest that (1) slurry-TXRF might be successfully used with moss material, (2) G. pulvinata might be a good biomonitor of trace metals air pollution in urban context, and (3) cemetery moss sampling could be a useful complement for monitoring urban areas.

Graphical abstract

We tested the hypothesis that cemeteries are appropriate moss sampling sites for the evaluation of air pollution in urban areas. We sampled 110 moss cushions (Grimmia pulvinata) growing on gravestones in 21 urban and peri-urban cemeteries in the Paris metropolitan area. The concentration of 20 elements in mosses was determined by a total reflection X-ray fluorescence technique coupled with a slurry sampling method. Statistical analysis revealed that:

- Urbanized Parisian areas crossed by traffic roads have the highest polluted cemeteries with a strong influence of main wind direction on the distribution of air pollutants

- As expected, small cemeteries with low tree density were heavily polluted

- Less obvious, large green spaces such as large cemeteries (Père Lachaise, Montmartre, Montparnasse) in the center of a dense metropolis like Paris present the same level of atmospheric trace metal pollution as cemeteries in less urbanized areas or nearing a very large forest. This suggests that even in densely urbanized areas, there is more spatial variability in pollution distribution than usually assumed and that large urban areas with low traffic and green filters such as trees are likely to intercept air pollutants

http://ift.tt/2cfWnC7

Microplastics affect assimilation efficiency in the freshwater amphipod Gammarus fossarum

Abstract

An important issue in assessing microplastics is whether this newly emerging type of pollution affects freshwater invertebrates. This study was designed to examine the interactions between the amphipod Gammarus fossarum and two types of microplastics. To determine the ingestion and egestion of polyamide (PA) fibres (500 × 20 μm), amphipods were exposed to four concentrations (100, 540, 2680, 13,380 PA fibres cm⁻² base area of glass beakers) and four exposure times (0.5, 2, 8, 32 h) as well as four post-exposure times (1, 2, 4, 16 h). We demonstrate a positive correlation between concentration and ingestion of PA fibres. Fibres were found in the gut after 0.5 h of exposure. Egestion was rapid and the digestive tract was empty 16 h after exposure ended. To investigate whether polystyrene (PS) beads (1.6 μm) can be taken up in the epithelial cells of the gut and the midgut glands, four concentrations (500, 2500, 12,500, 60,000 PS beads mL⁻¹) were tested. Cryosections exhibited fluorescent PS beads only within the gut lumen. In a 28-day feeding experiment with both, fibres and beads, we studied the amphipod's feeding rate, assimilation efficiency and wet weight change. The exposure to PA fibres (2680 PA fibres cm⁻² base area of glass beakers) significantly reduced the assimilation efficiency of the animals. While both tested polymer types are ingested and egested, PA fibres can impair the health and ecological functions of freshwater amphipods under continuous exposure.

http://ift.tt/2cfX3Yd

Metabolic and endocrine effects of bisphenol A exposure in market seller women with polycystic ovary syndrome

Abstract

Bisphenol A (BPA) is one of the synthetic monomer which can be found in the environment. Limited animal and human studies have demonstrated that BPA alters endocrine and or metabolic functions. The aims of the present study were to evaluate serum BPA level in marketing seller women with polycystic ovary syndrome (PCOS) and hormonal and metabolic effects of this exposure compared to a control paired group. In a case-control study, 62 PCOS women who work as marketing sellers and 62 healthy women with similar jobs were included. The two groups were body mass index (BMI)- and age-matched. Serum samples were analyzed for BPA content, fasting blood sugar (FBS), triglyceride, cholesterol, HDL and LDL levels, thyroid stimulating hormone (TSH) concentration, and LH:FSH ratio. Significant higher serum BPA content (0.48 ± 0.08 vs. 0.16 ± 0.04 ng/ml), triglyceride (103.05 ± 13.10 vs. 91.65 ± 12.52 mg/dl), cholesterol (165.05 ± 10.79 vs. 161.21 ± 10.31 mg/dl) levels and LH:FSH ratio (3.64 ± 0.86 vs. 0.62 ± 0.14) and significant lower TSH concentration (1.56 ± 0.68 vs. 2.15 ± 1.09 IU/ml) were detected in case against control group, respectively (P < 0.05). No significant differences were detected in FBS, LDL, and HDL levels between the two groups. Also, there were no significant associations between serum TSH concentration and BPA level neither in case (P = 0.269) nor in control (P = 0.532) groups. In BPA-exposed PCOS women, BPA level was higher than healthy women and this difference maybe the cause of significant differences in levels of triglyceride, cholesterol, TSH, and LH:FSH ratio. These observations confirm the potential role of BPA in PCOS pathophysiology.

http://ift.tt/2ctzSx3

Monitoring the clean-up operation of agricultural fields flooded with red mud in Hungary

Abstract

In the course of the clean-up operation after the red mud inundation in 2010, red mud was removed from the soil surface in places where the layer was more than 5 cm deep. Before its removal, the red mud seeped into the soil. In 2012, soil samples were taken from depths of 0 to 20 and 20 to 40 cm on some of the affected areas. The parameters investigated were pH, organic matter, salt%, and the total and mobile fractions of various elements. The values recorded in 2012 were compared with those measured immediately after the removal of the red mud in 2010 and with the background and clean-up target concentrations. The pH values remained below the designated limit, while the salt content only exhibited values in the weakly salty range on areas at the greatest distance from the dam. In the central part of the inundated area, total Na contents above the 900 mg/kg target value were observed, but the Na content in the 0–20-cm layer generally exhibited a decrease due to leaching. The pH and As concentration also showed a decline on several areas compared with the values recorded in 2010. Total As and Co contents in excess of the target values were recorded on the lowest-lying part of the flooded area, probably because the finest red mud particles were deposited the furthest from the dam, where they seeped into the soil. Nevertheless, the mobility and plant availability of both elements remained moderate. The total contents of both Co and Mo, however, exhibited a significant rise compared with both the background value and the 2010 data. The monitoring of the cleaned-up areas showed that after a 2-year period element concentrations that exceeded the target values and could be attributed to the red mud pollution were only detectable on the lowest-lying areas.

http://ift.tt/2cfW8Hs

Heavy metal in sediments of Ziya River in northern China: distribution, potential risks, and source apportionment

Abstract

The concentration partitioning between the sediment particle and the interstitial water phase plays an important role in controlling the toxicity of heavy metals in aquatic systems. The aim of this study was to assess the sediment quality in a polluted area of the Ziya River, Northern China. The contamination potential and bioavailability of six metals were determined from the concentrations of total metals and the bioavailable fractions. The results showed that the concentrations of Cr, Cu, Ni, Zn, and Pb exceeded the probable effect concentration at several sites. The high geoaccumulation indices showed that the sediments were seriously contaminated by Cd. The ratio of acid-volatile sulfide (AVS) to simultaneously extracted metal (SEM) was higher than 1, which indicated that the availability of metals in sediments was low. The risk assessment of interstitial waters confirmed that there was little chance of release of metals associated with acid-volatile sulfide into the water column. Values of the interstitial water criteria toxicity unit indicated that none of the concentrations of the studied metals exceeded the corresponding water quality thresholds of the US Environmental Protection Agency. Positive matrix factorization showed that the major sources of metals were related to anthropogenic activities. Further, if assessments are based on total heavy metal concentrations, the toxicity of heavy metals in sediment may be overestimated.

http://ift.tt/2ctzUFb

Distribution, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface water in industrial affected areas of the Three Gorges Reservoir, China

Abstract

Water samples were collected from wastewater treatment plant (WWTP), drain water (DW), major tributaries (MT), and main course of the Yangtze River (MY) in areas of three industrial parks (IPs) in Chongqing city in the Three Gorges Reservoir (TGR). Sixteen EPA priority polycyclic aromatic hydrocarbon (PAH) pollutants were quantified to identify the effects of industrial activities on water quality of the TGR. The results showed that 11 individual PAHs were quantified and 5 PAHs (naphthalene (Nap), acenaphthylene (Acy), benzo[k]fluoranthene (BkF), indeno[1,2,3-cd]pyrene (InP), and benzo[g,h,i]perylene (BgP)) were under detection limits in all of the water samples. Three-ring and four-ring PAHs were the most detected PAHs. Concentrations of individual PAHs were in the range of not detected (nd) to 24.3 ng/L. Total PAH concentrations for each site ranged from nd to 42.9 ng/L and were lower compared to those in other studies. The mean PAH concentrations for sites WWTP, DW, MT, and MY showed as follows: DW (25.9 ng/L) > MY (15.5 ng/L) > MT (14.0 ng/L) > WWTP (9.3 ng/L), and DW contains the highest PAH concentrations. Source identification ratios showed that petroleum and combustion of biomass coal and petroleum were the main sources of PAHs. The results of potential ecosystem risk assessment indicated that, although PAH concentrations in MT and MY are likely harmless to ecosystem, contaminations of PAHs in DW were listed as middle levels and some management strategies and remediation actions, like strengthen clean production processes and banning illegal sewage discharging activities, etc., should be taken to lighten the ecosystem risk caused by PAHs especially risks caused by water discharging drains.

http://ift.tt/2cfX3HH

Perovskite-type titanate zirconate as photocatalyst for textile wastewater treatment

Abstract

Calcium titanate zirconate, Ca(Ti_(1-x)Zr_x)O₃ (CZT), powders have been synthesised by the polymeric precursor method. The structural analysis of the CZT powders was monitored by X-ray diffraction (XRD), photoacoustic spectroscopy (PAS) and textural analysis. The photocatalytic properties were evaluated by methylene blue (MB) decomposition and real textile wastewater (RTW) combined treatment (coagulation/flocculation/photocatalysis). Chemical oxygen demand (COD) of RTW was successfully reduced from 6195 mg L⁻¹ (untreated) to 662 mg L⁻¹ after coagulation/flocculation with a tannin-based coagulant (Tanfloc®) and finally to 471 mg L⁻¹ after combined treatment (coagulation/flocculation/photocatalysis) applying ultraviolet radiation and CaTiO₃ as photocatalyst.

http://ift.tt/2ctA27q