Maximum Total Concentration Research Articles

The occurrence and distribution of antibiotics in the Karst river system in Kaiyang, Southwest China

Abstract To our knowledge, this was the first study to investigate the occurrence and distribution of antibiotics in the Karst river system in Kaiyang, Southwest China. Ten water samples were collected from the Karst river in Kaiyang, Southwest China. Thirty-five antibiotics, including nine sulfonamides, four tetracyclines, five macrolides, sixteen quinolones and chloramphenicol, were analyzed. The results suggest that antibiotics are widely prevalent in the Karst river, with macrolides and quinolones being the most dominant and occupying 47% and 43% of total antibiotic concentration, respectively. The maximum total concentrations of sulfonamides, tetracyclines, macrolides, and quinolones were 30.4, 421, 884, and 1,807 ng/L, respectively. Lincomycin, roxithromycin, nalidixic acid, ofloxacin, and norfloxacin were detected in all samples with a detection frequency of 100%. The main sources of antibiotics were wastewater treatment plants (WWTPs) and rural dumps that did not contain sanitary treatment, which accounted for 33% and 40% of the total antibiotics present in the Karst river. Due to an increase in river flow quantity, the presence of WWTPs and rural dumps did not affect the concentration and distribution of antibiotics in the Karst river; however, the mass flux of antibiotics were significantly affected by the contamination source and the poor natural attenuation.

Year-round presence of neonicotinoid insecticides in tributaries to the Great Lakes, USA.

To better characterize the transport of neonicotinoid insecticides to the world's largest freshwater ecosystem, monthly samples (October 2015-September 2016) were collected from 10 major tributaries to the Great Lakes, USA. For the monthly tributary samples, neonicotinoids were detected in every month sampled and five of the six target neonicotinoids were detected. At least one neonicotinoid was detected in 74% of the monthly samples with up to three neonicotinoids detected in an individual sample (10% of all samples). The most frequently detected neonicotinoid was imidacloprid (53%), followed by clothianidin (44%), thiamethoxam (22%), acetamiprid (2%), and dinotefuran (1%). Thiacloprid was not detected in any samples. The maximum concentration for an individual neonicotinoid was 230 ng L-1 and the maximum total neonicotinoids in an individual sample was 400 ng L-1. The median detected individual neonicotinoid concentrations ranged from non-detect to 10 ng L-1. The detections of clothianidin and thiamethoxam significantly increased as the percent of cultivated crops in the basins increased (ρ = 0.73, P = .01; ρ = 0.66, P = .04, respectively). In contrast, imidacloprid detections significantly increased as the percent of the urbanization in the basins increased (ρ = 0.66, P = .03). Neonicotinoid concentrations generally increased in spring through summer coinciding with the planting of neonicotinoid-treated seeds and broadcast applications of neonicotinoids. More spatially intensive samples were collected in an agriculturally dominated basin (8 sites along the Maumee River, Ohio) twice during the spring, 2016 planting season to provide further information on neonicotinoid inputs to the Great Lakes. Three neonicotinoids were ubiquitously detected (clothianidin, imidacloprid, thiamethoxam) in all water samples collected within this basin. Maximum individual neonicotinoid concentrations was 330 ng L-1 and maximum total neonicotinoid concentration was 670 ng L-1; median detected individual neonicotinoid concentrations were 7.0 to39 ng L-1.

Dry sliding behavior and friction layer formation in copper-free barite containing friction materials

The tribological behavior of materials used for vehicular car brakes is investigated using pin-on-disc tests. In particular, the disc was made of a commercial gray cast iron, used for real brake discs. The pins were made of newly developed formulations of friction materials, whose thread-line is the elimination of copper. This element was present in the selected bench-mark friction material, which is a low-metallic material, in which copper is replaced by re-arranging the overall composition and by adding increasing amounts of barite, up to a total maximum concentration of 33.5wt%. Wear products, namely the friction layers that formed on the mating surfaces of the pin materials, have been characterized to identify the main phenomena involved and influencing wear rate and friction coefficient. The main outcome of the research is the beneficial influence of barite, the compositional range that is important to target, the possible routes to be pursued, to improve the results achieved so far.

An Evaluation of the Phytochemical Properties of SomePomegranate Cultivars during Fruit Development and Ripening

The pomegranate fruit is a good source of bioactive compounds. The present study has investigated the biochemical and sensory characteristics of the arils of four Iranian commercial pomegranate cultivars namely Malase Shirine Saveh (MSS), Malase Torshe Saveh (MTS), Alak Shirine Saveh (ASS) and Agha Mohammad Ali (AMA) for several developmental and ripening stages during 45–180 days after fruit set (DAFS). The results showed that the total soluble solids (TSS), individual and total anthocyanin concentrations, and color parameters including chroma and a* values significantly increased, in contrast, the total phenolic concentration and color parameters (L* and hue angle) gradually decreased during developmental stages. Six anthocyanin pigments were found responsible for the red color of pomegranate juice. The quantity and the quality of the anthocyanin pigments were different among the cultivars and the various developmental stages. The predominant anthocyanin pigment at all developmental stages in all cultivars was cyanidin 3,5-diglucosides. The maximum total phenolic concentration was recorded at 45 DAFS for all cultivars. The highest antioxidant activity was recorded at 45 DAFS, and gradually decreased until 135 DAFS. Similar decrease was observed in total phenolic and flavonoid concentrations. Notably, increasing of antioxidant activity at the late-developmental stage was due to induction of the flavonoids and anthocyanins accumulation.

Acidogenic fermentation of vegetable and salad waste for chemicals production: Effect of pH buffer and retention time

This study investigated the effect of pH buffer and solids retention time (SRT) on the anaerobic fermentation of vegetable and salad waste (VSW). Experiments were carried out in batch and semi-continuous reactors at 35°C. In the batch experiments, the effect of pH buffer on the production of volatile fatty acids (VFAs) and ethanol was investigated. Acetate and butyrate were the main fermentation products. The maximum total product concentration was 43.3 and 18.5gCODl−1 in the buffered and unbuffered batch reactors resulting in a yield of 62 and 27% (CODtotalproduct/CODfeed) respectively. Volatile suspended solids (VSS) removal was higher in the buffered semi-continuous reactor (57%) compared to the unbuffered-acidic reactor (39%), but similar yields (15%, CODtotalproduct/CODfeed) were observed because biogas production was stimulated in the buffered reactor. The effect of SRT on the VSS removal and product distribution in unbuffered systems was investigated at 10, 20 and 30days SRT. The VSS removal increased as the SRT increased, ranging between 18.2–49.1%, likewise the total product concentration, 9.1–19.4gCODl−1, and product yield, 7–24% (CODtotalproduct/CODfeed). Acetate and butyrate were the predominent fermentation products at all conditions followed by caproate although caproate to this was only detected at 20 and 30days SRT. Total COD removal ranged between 15.2 and 35.1% with the highest removal observed at 30days SRT.

Production of vinegar from purple sweet potato in a liquid fermentation process and investigation of its antioxidant activity.

Acetobacter pasteurianus JST-S was screened from solid fermented grains of vinegar in China, identified by molecular analysis, and used for the production of purple sweet potato vinegar using purple sweet potato as the substrate. By orthogonal experiment, maximum total acid concentration (4.26% [v/v]) was achieved under optimized conditions as follows: fermentation time, 3.5days; ethanol content, 9% v/v; and inoculum size, 8% v/v. During the production of purple potato vinegar, the anthocyanin concentration decreased from 652.07 to 301.73μg/mL. The antioxidant activity of products, including diphenyl-picryl hydrazide radical-scavenging capacity (above 60%), reducing power (above 0.47), and hydroxyl radical-scavenging capacity (above 46%), showed positive linear regression (P<0.01), which could be related with the changes in anthocyanin concentration and antioxidant activities at different stages of vinegar fermentation. The acetic acid and other non-phenolic antioxidants in purple sweet potato vinegar may have contributed to the antioxidant activities. Results of these studies may provide a reference for the industrial production of vinegar by liquid fermentation of purple sweet potato.

Use of low-cost agro products as substrate in semi-continuous process to obtain carotenoids by Sporidiobolus salmonicolor

Abstract This work has studied the semi-continuous carotenoids production by Sporidiobolus salmonicolor (CBS 2636) comparing the use of complex substrates and agroindustrial residues. The maximum total carotenoids concentration was 4376 μg L−1 in a 264 h period with complex substrates (80 g L−1 glycerol, 5 g L−1 malt extract, and 15 g L−1 peptone) and 7388 μg L−1 in a 288 h period with agroindustrial residues (80 g L−1 crude glycerol, 80 g L−1 corn maceration water, and 20 g L−1 rice parboiling water), showing an of approximate 54% increase, under the following conditions: 25 °C, pHinitial of 4.0, 180 rpm agitation rate, 1.5 vvm aeration rate, with 50% working volume cut. The maximum productivity on total carotenoids was 34.8 and 41.4 g L−1 h−1, the maximum productivity on cells was 0.058 and 0.104 g L−1 h−1, with specific maximum growth speeds of 0.05 and 0.08 h−1, obtaining the major carotenoid all-trans-β-carotene (83% and 81%), respectively.

CO2 conversion in a non-thermal, barium titanate packed bed plasma reactor: The effect of dilution by Ar and N2

Carbon dioxide conversion upon dilution by argon and nitrogen at atmospheric pressure has been studied using a barium titanate packed bed, non-thermal plasma reactor. The results show that the packed bed reactor with the BaTiO3 ferroelectric packing material directly contacting to electrodes provided a higher CO2 conversion and energy efficiency than a dielectric barrier discharge reactor with and without packed materials using electrodes covered by dielectric layers. In the packed bed reactor, the CO2 conversion increased from 19% in pure CO2 to 36% upon diluting the CO2 with 80% argon and to 35% with 80% nitrogen at a specific energy input (SIE) of 36kJL−1. The energy efficiency was approximately constant at ca. 0.24mmolkJ−1 for pure CO2 dissociation upon increasing SIE, but decreases upon dilution by Ar and is more pronounced by N2. In addition to the major products of CO and O2, up to 100ppm of ozone was produced in a CO2/Ar plasma, but not in a CO2/N2 plasma where some nitrogen oxides (N2O, NO and NO2), were observed with a total maximum concentration of 3120ppm. Possible mechanisms are presented for the effect of Ar and N2 on the dissociation of CO2 and for the formation of O3, N2O and NOx based on discharge processes in the plasma and the subsequent chemistry. Electrical characterisation of the pure CO2, CO2/Ar and CO2/N2 plasmas was also undertaken. The results suggest the formation of by-products can be controlled by varying the dilution gas fraction and operating conditions.

Lab-scale pyrolysis of the Automotive Shredder Residue light fraction and characterization of tar and solid products

The general aim of this study is the recovery of Automotive Shredder Residue (ASR). The ASR light fraction, or car fluff, that was collected at an Italian shredding plant was pyrolysed at various temperatures (500–800°C) in a lab-scale reactor. The condensable gases (tar) and solid residue yields increased with decreasing temperature, and these products were characterized to suggest a potential use to reclaim them. The higher heating value (HHV) of tar was 34–37MJ/kg, which is comparable with those of fossil fuels. Furthermore, the ash content was low (0.06–4.98%). Thus, tar can be used as an alternative fuel. With this prospect, the concentrations of polychlorinated dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in tar were determined. The toxicity of tar changes with temperature (1–5ng I-TEQ/g), and the PCDFs significantly contribute to tar toxicity, which was 75–100% with a maximum of 99.6% at 700°C. Regarding the characterization of the solid residue, the low HHV (2.4–3.3MJ/kg) does not make it suitable for energy recovery. Regarding material recovery, we considered its use as a filler in construction materials or a secondary source for metals. It shows a high metal concentration (280,000–395,000mg/kg), which is similar at different pyrolysis temperatures. At 500°C, polycyclic aromatic hydrocarbons (PAHs) were not detected in the solid residue, whereas the maximum total PAH concentration (19.41ng/g, 700°C) was lower than that in fly ash from MSWI. In conclusion, 500°C is a suitable pyrolysis temperature to obtain valuable tar and solid residue.

Pharmacokinetics of 400 mg ropivacaine after periarticular local infiltration analgesia for total knee arthroplasty

Although considered safe, no pharmacokinetic data of high dose, high volume local infiltration analgesia (LIA) with ropivacaine without the use of a surgical drain or intra-articular catheter have been described. The purpose of this study is to describe the maximum total and unbound ropivacaine concentrations (Cmax , Cu max ) and corresponding maximum times (Tmax , Tu max ) of a single-shot ropivacaine (200 ml 0.2%) and 0.75 mg epinephrine (1000 μg/ml) when used for LIA in patients for total knee arthroplasty. In this prospective cohort study, 20 patients were treated with LIA of the knee for primary total knee arthroplasty. Plasma samples were taken at 20, 40, 60, 90, 120, 240, 360 min and at 24 h after tourniquet release, in which total and unbound ropivacaine concentrations were determined. Results are given as median [IQR]. Highest ropivacaine concentration (Cmax ) was 1.06 μg/ml [0.34]; highest unbound ropivacaine concentration (Cu max ) was 0.09 μg/ml [0.05]. The corresponding time to reach the maximum concentration for total ropivacaine was 312 min [120] after tourniquet release, and for the unbound fraction 265 [110] min after tourniquet release. Although great inter-individual variability was found between the maximum ropivacaine concentrations, both maximum total and unbound serum concentrations of ropivacaine remained well below the assumed systemic toxic thresholds of 4.3 and 0.56 μg/ml.

Tyrosine and aurora kinase inhibitors diminish transport function of multidrug resistance-associated protein (MRP) 4 and breast cancer resistance protein (BCRP)

&lt;p class="PaperKeywordTitle"&gt;Tyrosine and aurora kinases are important effectors in signal transduction pathways that are often involved in aberrant cancer cell growth. Tyrosine (TKI) and aurora (AKI) kinase inhibitors are anti-cancer agents specifically designed to target such signaling pathways through TKI/AKI binding to the ATP-binding pocket of kinases thereby leading to diminished kinase activity. Some TKIs have been identified as inhibitors of ATP-binding cassette (ABC) transporters such as P-glycoprotein and breast cancer resistance protein (BCRP), which are commonly upregulated in malignant cells. TKI/AKIs have been investigated as ABC transporter inhibitors in order to facilitate the accumulation of concomitantly administered chemo-therapeutics within cancer cells. However, ABC transporters are prominently expressed in the liver and other eliminating organs, and their inhibition has been linked to intracellular accumulation of drugs, altered disposition, and toxicity. The potential for TKIs/AKIs to inhibit other important hepatic efflux transporters, particularly multidrug resistance-associated proteins (MRPs), remains unknown. The aim of the current study was to compare the inhibitory potency of 20 selected TKI/AKIs against MRP4 and BCRP through the use of inverted membrane vesicle assays. Relative IC&lt;sub&gt;50 &lt;/sub&gt;values were estimated by determining TKI/AKI inhibition of MRP4-mediated [&lt;sup&gt;3&lt;/sup&gt;H]-dehydroepiandrosterone sulfate uptake and BCRP-mediated [&lt;sup&gt;3&lt;/sup&gt;H]-estrone sulfate uptake. To provide insight to the clinical relevance of TKI/AKI inhibition of ABC efflux transporters, the ratio of the steady-state maximum total plasma concentration (C&lt;sub&gt;ss&lt;/sub&gt;) to the IC&lt;sub&gt;50&lt;/sub&gt; for each compound was calculated with C&lt;sub&gt;ss&lt;/sub&gt;/IC&lt;sub&gt;50&lt;/sub&gt; ratio &amp;gt;0.1 deemed potentially clinically relevant. Such analysis identified several potentially clinically relevant inhibitors of MRP4: alisertib, danusertib, erlotinib, lapatinib, neratinib, nilotinib, pazopanib, sorafenib, and tozasertib. The potentially clinically relevant inhibition of BCRP was much more extensive and included alisertib, barasertib, danusertib, enzastaurin, erlotinib, gefitinib, imatinib, neratinib, nilotinib, pazopanib, selumetinib, sorafenib, sunitinib, tozasertib, and vandetanib. These findings indicate the significant potential for TKI/AKIs to inhibit multiple ABC efflux transporters. The resulting inhibition data could provide insight regarding the clinical interpretation of pharmacokinetic/pharmacodynamic outcomes when TKI/AKIs are administered concomitantly with additional chemotherapeutic agents.&lt;/p&gt;

Викиди зважених часток від повітряних суден під час експлуатації в межах аеропорту

Мета: Викиди авіадвигунів в межах приземного граничного шару під час етапів зльоту та посадки призводять до значного погіршення якості повітря в межах аеропорту та на прилеглих житлових територіях. На сьогодні, основними об'єктами забруднення повітря в аеропортах є оксиди азоту і зважені частки (ЗЧ10, ЗЧ2.5 і ультрадісперсні ЗЧ), які спричиняють виникнення відповідно фотохімічного смогу та туману з наступними несприятливими наслідками для здоров’я населення. Аналіз результатів інвентаризації викидів ЗЧ у головних аеропортах Європи вказує на домінантність викидів авіадвигунів та допоміжної силової установки. Стаття спрямована на аналіз теоретичних та експериментальних досліджень із розподілу часток за розміром у викидах авіадвигунів, а також особливостей їх морфології та внутрішньої структури, оскільки зазначені властивості мають важливе значення для розуміння потенційного впливу ЗЧ на здоров'я населення. Стаття також надає детальний опис основних методів розрахунку викидів та дисперсії ЗЧ від авіадвигуна протягом злітно-посадкового циклу повітряного судна. Методи: аналітичне розв'язання рівняння атмосферної дифузії використовується для розрахунку максимальної концентрації ЗЧ від точкового джерела емісії. Концентрація ЗЧ змінюється обернено пропорційно швидкості вітру u1 і прямо пропорційно вертикальній складовій коефіцієнту турбулентного обміну k1/u1. Оцінка концентрації нелетучої ЗЧ враховує розмір і форму ЗЧ. Модель PolEmiCa обчислює розподіл фракцій ЗЧ у викидах від авіадвигунів та ДСУ (висота установки H = 4,5 м для Ту-154). Результати: Максимальна концентрація ЗЧ у викидах ДСУ вища, а відповідна відстань менша, у порівнянні з випадком для газу. Полідисперсність призводить до розподілу максимумів концентрацій в просторі для окремих фракцій за напрямком вітру, що призводить до зменшення загальної максимальної концентрації. Обговорення: Хоча емісія ДСУ сягає рівня авіадвигунів, викиди ДСУ не сертифіковані ІСАО. Отже, зазначена проблема є актуальною для місцевої якості повітря, зокрема для розробки моделі та визначення методів виявлення складової викидів авіадвигунів і ДСУ у загальне забруднення повітря аеропорту ЗЧ.

Occurrence of microcystins and anatoxin-a in eutrophic lakes of Saint Petersburg, Northwestern Russia

Abstract Cyanobacteria are natural components of many freshwater bodies worldwide. In Russian lakes, the presence of potentially toxic cyanobacteria was also frequently observed. Our study was conducted in Sestroretskij Razliv Lake (Razliv) and Lower Suzdal Lake (Suzdal) in Saint Petersburg region, Northwestern Russia, which differ from one another in eutrophic status and composition of the phytoplankton community. In large, shallow, artificial and hypertrophic Razliv, Aphanizomenon flos-aquae and Microcystis spp. dominated. Fourteen microcystin variants were identified in this lake. The maximum concentration of extracellular microcystins was 41.37 μg l−1. In eutrophic and shallow Suzdal, dominated by Planktothrix agardhii, nine microcystin variants and anatoxin-a (&lt;0.54 μg l−1) were found. The maximum total concentration of extracellular MCs in this lake was 2.89 μg l−1. Regular studies into the production of cyanotoxins in these water bodies were carried out for the first time. The analyses performed with the application of high-resolution tandem mass spectrometry revealed the presence of microcystins in 59% of the samples collected during a 3-year study. Since both lakes are used for recreational purposes, the regular monitoring program should be implemented to protect water users from a potential risk that was identified in our study.

Historical sources of polychlorinated biphenyls to the sediment of the New York/New Jersey Harbor

Using dated sediment cores, polychlorinated biphenyl (PCB) congener concentrations in the New York/New Jersey Harbor and Lower Hudson River were investigated using Positive Matrix Factorization. Of the seven factors resolved, six represent Aroclors in various stages of weathering. Factor 1 resembles Aroclor 1242 and is consistent with the Upper Hudson River PCB signal associated with the General Electric capacitor plants near Hudson Falls, NY. This factor is the dominant source of PCBs in the upper layers of the sediment core collected in the Lower Hudson River. Factor 2 (Aroclor 1248) was the dominant PCB component in the core depths corresponding with around 1970, but it has decreased more rapidly since its peak (estimated half-life of about 5 years) than factor 1 (half-life of about 14 years), suggesting that PCBs from the Upper Hudson have delayed the recovery of the Harbor from PCB contamination. The seventh factor, comprised of PCBs 206, 208, and 209, was greatest in concentration in the deepest core slices and is thought be associated with inadvertent production of PCBs during the manufacture of titanium dioxide and/or with foundry waxes containing PCBs. PCB 11, which is thought to be associated with the use of color organic pigments, was examined separately and was detected in sediment throughout the Harbor. Its maximum concentrations generally occurred at the same depth as the maximum total PCB concentrations, suggesting that PCB 11 concentrations decreased after the mid-1970s.

Regional assessment of concentrations and sources of pharmaceutically active compounds, pesticides, nitrate, and E. coli in post-glacial aquifer environments (Canada).

There is growing concern worldwide about the exposure of groundwater resources to pharmaceutically active compounds (PhACs) and agricultural contaminants, such as pesticides, nitrate, and Escherichia coli. For regions with a low population density and an abundance of water, regional contamination assessments are not carried out systematically due to the typically low concentrations and high costs of analyses. The objectives of this study were to evaluate regional-scale contaminant distributions in untreated groundwater in a rural region of Quebec (Canada). The geological and hydrogeological settings of this region are typical of post-glacial regions around the world, where groundwater flow can be complex due to heterogeneous geological conditions. A new spatially distributed Anthropogenic Footprint Index (AFI), based on land use data, was developed to assess surface pollution risks. The Hydrogeochemical Vulnerability Index (HVI) was computed to estimate aquifer vulnerability. Nine wells had detectable concentrations of one to four of the 13 tested PhACs, with a maximum concentration of 116ng·L-1 for benzafibrate. A total of 34 of the 47 tested pesticides were detected in concentrations equal to or greater than the detection limit, with a maximum total pesticide concentration of 692ng·L-1. Nitrate concentrations exceeded 1mg·L-1 N-NO3 in 15.3% of the wells, and the Canadian drinking water standard was exceeded in one well. Overall, 13.5% of the samples had detectable E. coli. Including regional-scale sources of pollutants to the assessment of aquifer vulnerability with the AFI did not lead to the identification of contaminated wells, due to the short groundwater flow paths between recharge and the sampled wells. Given the occurrence of contaminants, the public health concerns stemming from these new data on regional-scale PhAC and pesticide concentrations, and the local flow conditions observed in post-glacial terrains, there is a clear need to investigate the sources and behaviours of local-scale pollutants.

Indoor secondary organic aerosols formation from ozonolysis of monoterpene: An example of d-limonene with ammonia and potential impacts on pulmonary inflammations.

Monoterpene is one class of biogenic volatile organic compounds (BVOCs) which widely presents in household cleaning products and air fresheners. It plays reactive role in secondary organic aerosols (SOAs) formation with ozone (O3) in indoor environments. Such ozonolysis can be influenced by the presence of gaseous pollutants such as ammonia (NH3). This study focuses on investigations of ozone-initiated formation of indoor SOAs with d-limonene, one of the most abundant indoor monoterpenes, in a large environmental chamber. The maximum total particle number concentration from the ozonolysis in the presence of NH3 was 60% higher than that in the absence of NH3. Both of the nuclei coagulation and condensation involve in the SOAs growth. The potential risks of pulmonary injury for the exposure to the secondary particles formed were presented with the indexes of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) expression levels in bronchoalveolar lavage fluid (BALF) upon intratracheal instillation in mice lung for 6 and 12h. The results indicated that there was 22-39% stronger pulmonary inflammatory effect on the particles generated with NH3. This is a pilot study which demonstrates the toxicities of the indoor SOAs formed from the ozonolysis of a monoterpene.

Determination of total arsenic and arsenic species in drinking water, surface water, wastewater, and snow from Wielkopolska, Kujawy-Pomerania, and Lower Silesia provinces, Poland.

Arsenic is a ubiquitous element which may be found in surface water, groundwater, and drinking water. In higher concentrations, this element is considered genotoxic and carcinogenic; thus, its level must be strictly controlled. We investigated the concentration of total arsenic and arsenic species: As(III), As(V), MMA, DMA, and AsB in drinking water, surface water, wastewater, and snow collected from the provinces of Wielkopolska, Kujawy-Pomerania, and Lower Silesia (Poland). The total arsenic was analyzed by inductively coupled plasma mass spectrometry (ICP-MS), and arsenic species were analyzed with use of high-performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Obtained results revealed that maximum total arsenic concentration determined in drinking water samples was equal to 1.01 μg L−1. The highest concentration of total arsenic in surface water, equal to 3778 μg L−1 was determined in Trująca Stream situated in the area affected by geogenic arsenic contamination. Total arsenic concentration in wastewater samples was comparable to those determined in drinking water samples. However, significantly higher arsenic concentration, equal to 83.1 ± 5.9 μg L−1, was found in a snow sample collected in Legnica. As(V) was present in all of the investigated samples, and in most of them, it was the sole species observed. However, in snow sample collected in Legnica, more than 97 % of the determined concentration, amounting to 81 ± 11 μg L−1, was in the form of As(III), the most toxic arsenic species.

Fusidic Acid Inhibits Hepatic Transporters and Metabolic Enzymes: Potential Cause of Clinical Drug-Drug Interaction Observed with Statin Coadministration.

Fusidic acid (FA), which was approved in the 1960s in many European and Asian countries, has gained renewed interest due to its continued effectiveness against methicillin-resistant Staphylococcus aureus As rhabdomyolysis has been reported upon coadministration of FA with statins, we aimed to elucidate the underlying molecular mechanisms that contribute to FA-statin drug-drug interactions. Because of the association between rhabdomyolysis and increased exposure to statins, we investigated if cytochrome P450 (CYP) enzymes and transporters involved in the disposition of various statins are inhibited by FA. FA was found to inhibit BCRP and OATP1B1 but not P-gp. In overexpressing cell systems, FA inhibited BCRP-mediated efflux (50% inhibitory concentration [IC50], ∼50 to 110 μM) and OATP1B1-mediated uptake (IC50, ∼4 to 35 μM) of statins at clinically relevant concentrations achievable in the intestine and liver (based on a 550-mg oral dose of FA, the expected maximum theoretical gastrointestinal concentration is ∼4 mM, and the maximum total or unbound concentration in the inlet to the liver was reported to be up to 223 μM or 11 μM, respectively, upon multiple dosing). Similarly, FA inhibited metabolism of statins in human liver microsomes (IC50, ∼17 to 195 μM). These data suggest that FA inhibits at least 3 major dispositional pathways (BCRP, OATP1B1, and CYP3A) and thus affects the clearance of several statins. We confirmed that FA is eliminated via phase 1 metabolism (primarily via CYP3A); however, there is also some phase 2 metabolism (mediated primarily by UGT1A1). Taken together, these data provide evidence for molecular mechanisms that may explain the occurrence of rhabdomyolysis when FA is administered with statins.

Mechanisms of cementitious material deterioration in biogas digester

Digesters produce biogas from organic wastes through anaerobic digestion processes. These digesters, often made of concrete, suffer severe premature deterioration caused mainly by the presence of fermentative microorganisms producing metabolites that are aggressive towards cementitious materials.To clarify the degradation mechanisms in an anaerobic digestion medium, ordinary Portland cement paste specimens were immersed in the liquid fraction of a running, lab-scale digester for 4weeks. The anaerobic digestion medium was a mixture of a biowaste substrate and sludge from municipal wastewater treatment plant used as a source of anaerobic bacteria.The chemical characteristics of the anaerobic digestion liquid phase were monitored over time using a pH metre, high performance liquid chromatography (HPLC) and ion chromatography (HPIC). An initial critical period of low pH in the bioreactors was observed before the pH stabilized around 8. Acetic, propionic and butyric acids were produced during the digestion with a maximum total organic acid concentration of 50mmolL−1. The maximum ammonium content of the liquid phase was 40mmolL−1, which was about seven times the upper limit of the highly aggressive chemical environment class (XA3) as defined by the European standard for the specification of concrete design in chemically aggressive environments (EN 206).The changes in the mineralogical, microstructural and chemical characteristics of the cement pastes exposed to the solid and liquid phase of the digesters were analysed at the end of the immersion period by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDS) and electron-probe micro-analysis (EPMA). A 700-μm thick altered layer was identified in the cement paste specimens. The main biodeterioration patterns in the bioreactors' solid/liquid phase were calcium leaching and carbonation of the cement matrix.

Organotins in fish muscle and liver from the Polish coast of the Baltic Sea: Is the total ban successful?

Muscle and liver tissues of nine fish species were analyzed to assess butyltin and phenyltin contamination. The samples were collected from three basins located in the Southern Baltic Sea coastal zone that each represent different potential for organotin pollution. Maximum total concentrations of butyltin compounds (BTs) in the fish muscles and livers were 715 and 1132ng Sn g−1 d.w., respectively, whereas triphenyltin (TPhT) was not detected. In the muscle samples, the predominant compound in the sum of butyltins was tributyltin (TBT), while in the liver samples, tributyltin degradation products were found in the majority. The results demonstrate that 6–7years after the implementation of the total ban on harmful organotin use in antifouling paints, butyltins remain present in fishes from the Polish coast of the Baltic Sea. According to the HELCOM recommendation, eight samples exceeded the good environmental status boundary for tributyltin in seafood.