The use of fasting vs. non-fasting triglyceride concentration for estimating the prevalence of high LDL-cholesterol and metabolic syndrome in population surveys

<p>Abstract</p> <p>Background</p> <p>For practical reasons it is not easy to obtain fasting samples in large population health surveys. Non-fasting triglyceride (Tg) values are difficult to interpret. The authors compared the accuracy of statistically corrected non-fasting Tg values with true fasting values and estimated the misclassification of subjects with high low-density lipoprotein cholesterol (LDL-C) and the metabolic syndrome.</p> <p>Methods</p> <p>Non-fasting blood was obtained from a population-based sample of 4282 individuals aged 24-75 years in the National FINRISK 2007 Study. Fasting blood samples were drawn from the same persons 3 months later. Non-fasting serum Tg values were converted into fasting values using previously published formula. LDL-C was calculated and classification of the metabolic syndrome was carried out according to three different latest guidelines.</p> <p>Results</p> <p>The median (25^th, 75th percentile) non-fasting serum Tg concentration was 1.18 (0.87, 1.72) mmol/L and after postprandial correction 1.06 (0.78, 1.52) mmol/L. The true-fasting serum Tg concentration was 1.00 (0.75, 1.38) mmol/L (<it>P </it>< 0.001) vs. non-fasting and corrected value. Bias of the corrected value was +5.9% compared with the true-fasting Tg. Of the true fasting subjects, 56.4% had LDL-C ≥3.00 mmol/L. When calculated using non-fasting serum Tg, the prevalence of high LDL-C was 51.3% and using statistically corrected Tg it was 54.8%. The prevalence of metabolic syndrome was 35.5% among fully fasted persons and among non-fasting subjects 39.7%, which after statistical correction of Tg decreased to 37.6% (P < 0.001 for all comparisons).</p> <p>Conclusions</p> <p>Correction of non-fasting serum Tg to fasting values plays a minor role in population studies but nevertheless reduces misclassification of calculated high LDL-C from 5.1 to 1.6% and the metabolic syndrome from 4.2 to 2.1%.</p

Coagulation and size fractionation studies on pulp and paper mill process and wastewater streams

Abstract This thesis aims to increase our knowledge about the characteristics of chemical pulp process and wastewaters and how problematic substances, e.g. wood extractives, could be removed effectively and selectively by coagulation–flocculation with either internal or external water treatment. Characterization was performed by investigating kraft pulp bleaching filtrates, as well as wastewater, before (influent) and after (effluent) the activated sludge treatment by means of a range of chemical analyses and by carrying out size fractionation studies. Cationic polyelectrolytes were used to purify oxygen stage bleaching filtrate, and charge analyses (zeta potential, charge quantity) were carried out in order to understand the coagulation phenomenon. In activated sludge treatment, the enhancement of particle removal, either by filtration or using a chemical in the primary clarifier, would lead to savings in aeration costs and result in a more stable process. Microfiltration already with a large pore size (8 µm) removed 30–50% of the wood extractives from the influent. Separate treatment stages for certain wastewater fractions, e.g. debarking plant effluent, would ensure cost-efficiency. After the activated sludge process, the wood extractives were present as particles (18%) and &lt; 3 kDa fraction (82%). β-sitosterol occurred only in particles in the effluent. The release of harmful components into the environment could be decreased by microfiltration (e.g. 0.45 µm) of the final effluent or using a chemical in the secondary clarifier. Interestingly a huge increase in BOD was realized in the 3 kDa fraction of both influent and effluent, which indicated the presence of toxic substances in the larger fractions. After passing the effluent into the water system, there might be a similar jump in the BOD because the effluent is diluted many-fold. This would contribute to the formation of areas with an oxygen deficit. In the coagulation–flocculation studies, effective and selective removal of wood extractives (92%) from the oxygen stage filtrate was obtained with a cationic polyelectrolyte of medium molecular weight and medium charge density at 72 °C and pH 5–6. The multimodal zeta potential distribution gave more information than the average zeta potential. Aggregation of colloidal particles occurred when only one zeta potential was observed. The number of different zeta potentials diminished with decreasing pH and after exceeding a certain polyelectrolyte dosage level

Evaluating the influence of pH adjustment on chemical purification efficiency and the suitability of industrial by-products as alkaline agents

Abstract Metal salts of iron are currently used in several treatment facilities purifying peat extraction runoff water. Although chemical purification is considered best available technology for the treatment of this natural humic water, fluctuations in purification efficiency occur with low pH (3–4) and high metal concentration found in treated waters. The need for pH neutralisation increases the costs and overall environmental impacts related to chemical purification. The use of industrial by-products can decrease costs while supporting the sustainable use of natural resources and the principle of a circular economy. This study investigated the suitability of a range of calcium-based alkaline products (including by-products of the paper, cement and mineral industries) for neutralisation of chemically treated runoff water. The influence of the time of pH adjustment relative to time of coagulant addition (before coagulant, after but within coagulation, during flocculation and after sedimentation) on purification efficiency was evaluated. The hypotheses that the physical form of the coagulant was a relevant factor affecting purification was also assessed. The best performing pH-adjusting products were cement kiln dust (CaO and SiO₂) and Mahtikalkki (Ca(OH)₂, CaCO₃ and CaO), by-products of the cement and paper industry, respectively. Time of pH adjustment in relation to time of coagulation addition had a significant influence on purification efficiency, especially when solid coagulant was used. Adjustment of pH at 30 s before coagulant dosing resulted in a negative effect on treatment results. Based on results obtained, suitable points of pH adjustment are during the flocculation stage or at the outlet of sedimentation, particularly if solid coagulants are used

Sustainable tannin-based coagulants synthesized through Mannich reaction using melamine as an amine source for water treatment applications

Abstract This study explored the potential of melamine, as the nitrogenating source for the cationization of pulverized quebracho and spruce tannins. The influence of modification conditions on the properties of the coagulants was studied by varying the formaldehyde and melamine ratios with different activation times and temperatures. Based on considerations of charge density and shelf life, the most viable modifications were established as coagulants synthesized with a 1:0.52 formaldehyde to melamine molar ratio at 70 °C. At optimal conditions, the charge density of the quebracho and spruce coagulants was 2.22 meq/g and 1.04 meq/g, respectively, and the residual formaldehyde content in the coagulants was low. The developed synthesis of this study demonstrated a clear advantage over previous methods due to the rapid modification step. X-ray photoelectron spectroscopy (XPS) confirmed the emergence of an amine which signifies a successful Mannich reaction in the coagulant. Although optimal modification conditions for the coagulants were established at 70 °C (5-min activation time), the average molecular weight could not be determined for these conditions. Nevertheless, electrospray ionization mass spectrometry (ESI-MS) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry measurements revealed that the tannin-based coagulants obtained at lower temperatures (23 °C and 45 °C) possessed low average molecular weight (approx. 800–900 Da). Furthermore, ESI-MS and MALDI-TOF spectra showed that the Mannich modification resulted in the depolymerisation of the quebracho tannin, leading to a reduction in units of higher mass fractions in the synthesized coagulant, which contrasted with the spruce tannin. Jar test experiments with surface and industrial process waters demonstrated that the tannin coagulants enhanced particle settling effectively

Surface modification of pine bark with quaternary ammonium groups and its use for vanadium removal

Abstract Chemically modified pine bark was synthesized by using glycidyl trimethyl ammonium chloride (GTMAC) in the presence of sodium hydroxide. Optimization of the modification parameters was performed in order to maximize vanadium removal. Parameters included the initial NaOH concentration (0.01–2% w/v), GTMAC dosage (0.0067–0.0805 mol/g), modification time (1–6 h), modification temperature (40–80 ℃) and volume (25–100 mL). The optimal modification conditions were found to be 0.1% NaOH (w/v), 0.0134 mol/g GTMAC, 3 h and 60 ℃. The initial NaOH concentration played the most important role in successful modification while the GTMAC/NaOH ratio and volume had no significant effect under the studied conditions. Leaching of organic substances from the modified product was minor in comparison with raw pine bark. XPS analysis confirmed that quaternary nitrogen was successfully grafted onto the pine bark and that the BET surface area increased in the modification. The maximum vanadium adsorption capacity of the optimized product was found to be 32.3–35.0 mg/g at different temperatures (20 ℃, 15 ℃ and 5 ℃) at pH 4 with a contact time of 24 h, and the adsorption data was in very good agreement with the Freundlich and Redlich-Peterson models. The adsorption kinetics can be described well by the Elovich equation. Fitting the kinetic data with intra-particle diffusion and Boyd models showed that the adsorption process was controlled by both film and intra-particle diffusion, while intra-particle diffusion was the rate-limiting step. Regeneration studies demonstrated that, as a recyclable product, modified pine bark can be used effectively in real industrial processes for vanadium removal

Iron-modified peat and magnetite-pine bark biosorbents for levofloxacin and trimethoprim removal from synthetic water and various pharmaceuticals from real wastewater

Abstract Humans are at significant risk of antibiotic resistance genes (ARGs) and antimicrobial resistance (AMR) via exposure to pharmaceutical contaminants in water, so there is a strong need for cost-effective environmental solutions to mitigate this crisis. This study introduces iron-modified peat and magnetite-pine bark as efficient, low-cost and green biosorbents for the adsorption of pharmaceutical contaminants from wastewater. Peat biomass, modified by iron extracted from a groundwater treatment sludge was dissolved in acid to prepare the iron-modified peat biosorbent, and pine (Pinus sylvestris) bark as a forest industry by-product was mixed with iron salts (Fe³⁺: Fe²⁺ = 2:1) to obtain the magnetite biosorbent. The adsorption of levofloxacin was little influenced by pH compared to trimethoprim. The equilibrium removal efficiency of antibiotics over both biosorbents was reached after 180 min contact time. The maximum adsorption capacity over iron-modified peat was about 200 mg/g for both antibiotics and over magnetite-pine bark 153.0 mg/g for levofloxacin and 184.1 mg/L for trimethoprim. Possible antibiotic adsorption mechanisms were proposed based on the Fourier transform infrared spectroscopy (FTIR) analysis. Experiments with real wastewater effluent revealed trimethoprim removal of 56.6–84.3% (dosage: 3 g/L). Moreover, a variety of other pharmaceuticals were removed by the biosorbents

Removal of nitrate from underground mine waters using selective ion exchange resins

Abstract The removal of nitrogen from wastewaters is of great importance due to the harmful effects of nitrogen in the environment. In this study, nitrate removal from two underground mine waters was investigated by strong anion exchange resins (Lewatit MonoPlus SR 7 (referred to as SR7, macroporous), Purolite A520E (A520E, macroporous), Purolite A300E (A300E, gel)) in continuous-flow columns. Both mine waters had similar nitrate concentrations (NO₃-N: Mine A 32 mg/l and Mine B 37 mg/l) but contained different levels of chlorides and sulphates. Overall, all three resins removed nitrate from real underground mine waters effectively. In both mine waters, the earliest breakthrough was registered for resin A300E while resins SR7 and A520E had similar breakthrough points. Chloride was identified as a more competitive ion for nitrate than sulphate with resins SR7 and A520E, as their breakthrough curves shifted from left to right when the water was changed from Mine A (higher concentration of Cl⁻) to Mine B (higher concentration of SO₄²⁻). Resin A300E showed a somewhat higher sulphate uptake than the other two resins, which indicates its lower selectivity. This study provides new insight into how selectively nitrate is removed from real underground mine waters by polystyrene resins with different trialkyl functional groups and porosity

Removal of metals from mine drainage waters by in situ mineral sorbent-based pilot filter systems

Abstract Discharge of metal-containing wastewater streams into the environment is an environmental concern because these pollutants do not degrade and tend to bioaccumulate. A number of laboratory-based investigations on the effectiveness of a wide range of filter materials for metal removal from diluted wastewater streams have been reported. However, only a few pilot or full-scale investigations have been conducted. Therefore, this study investigated the metal retention capabilities of mineral-based filter materials (commercially available mineral product (5–15 mm), recycled mineral material (2–4 mm) and slag by-product (2–4 and 4–16 mm)) when used in pilot-scale filter systems under continuous operation in a closed mining area in North Ostrobothnia, Finland, between June and October 2017. The influence of material particle size on system function and on metal retention efficiency was also evaluated. The results revealed that system performance was dependent on material composition and particle size (smaller particle size being more effective). The highest metal removal efficiencies (Zn, Ni, Cd, Cu and Pb) and largest amount of water treated (per volume of material applied) were achieved by an aluminium oxide-based recycled mineral material (2–4 mm). While smaller-grained materials performed better in terms of removal efficiency, the removal rates achieved by coarser-grained, commercially available mineral product (5–15 mm) were comparable to those achieved by small-grained slag (2–4 mm). Full-scale systems using the recycled mineral product (2–4 mm) would have an approximately two-fold longer material replacement time than systems using the slag (2–4 mm). Replacement time for the larger-grained materials tested could not be determined, due to problems with freezing. Overall, the recycled mineral material tested can be recommended for full-scale tests, especially when high zinc removal rates are required

Pilot-scale field study for vanadium removal from mining-influenced waters using an iron-based sorbent

Abstract This study investigated the removal of vanadium from mining waters at a closed mine site (Mustavaara, Finland) using granular ferric oxyhydroxide (CFH-12) on pilot scale. Two filter systems, pilot A and pilot B, were placed in different streams, where the influent in pilot A contained a higher and very variable vanadium concentration (6.46–99.1 mg/L), while the pilot B treated influent had lower vanadium concentrations (0.443–2.33 mg/L). The operation periods were 51 days for pilot A and 127 days for pilot B. Water quality analyses revealed that vanadium was efficiently captured in the filter system in both pilots. X-ray fluorescence analysis revealed that the filter beds were not fully saturated with vanadium. X-ray photoelectron spectroscopy confirmed that oxidised vanadium (5⁺) existed in the used CFH-12 and the carbon content in the used material had increased due to the adsorbed organic compounds. For comparison, lab-scale coagulation experiments were conducted using ferric sulphate for the influent of pilot A (the sampled batch contained 15.9 mg/L V). The optimum coagulant dosage was 350 mg/L (&gt; 93% vanadium removal) at the original pH (7.8–7.9) of the influent, whereas the required coagulant amount decreased when the influent pH was adjusted to 4.6–4.8

Purifying water with plant-based sustainable solutions:tannin coagulants and sorbents

Abstract More and more efforts are being made to find efficient bio-based water and wastewater treatment products. Especially the use of tannin-based materials has become more prevalent in recent years due to the wide availability of sustainable tannin sources. This article provides an updated literature review on the potential for tannin use for coagulants and adsorbent synthesis and practical applicability in water purification. Tannin coagulants work well in many applications, especially in color, turbidity, and COD removal from industrial waters, and are often even better than conventional ones (e.g., metal salts). One of the most significant benefits of tannin coagulants is their small effect on the pH of the treated water. Also, tannin coagulants can work at a wide pH range, and sludge volume is typically smaller than with metal salts. However, it is worth noting that the performance varies widely among tannin coagulants. Tannin-derived resins and composites have been synthesized and evaluated as adsorbents for water purification. In general, tannin-derived adsorbents present good adsorption capacities for metals, antimony, cationic dyes, and uranium ions, owing to their chelating ability and negative surface charge in the pH conditions of interest and reducing power in the case of chromium(VI). With simple chemical modifications, tannin can be converted into effective sorbents for more challenging pollutants. More research is needed to test tannin materials on a larger scale and evaluate their overall benefits and cost-effectiveness