concentration levels
Recently Published Documents


TOTAL DOCUMENTS

1164
(FIVE YEARS 344)

H-INDEX

47
(FIVE YEARS 5)

Author(s):  
Hallvard Haanes ◽  
Trine Kolstad ◽  
Ingvild Egen Finne ◽  
Bård Olsen

Radon is an important contributor to public radiation dose and it is important to monitor levels in homes and introduce measures to reduce radon concentration levels, both overall and where levels are especially high. In Norway, new building regulations were introduced in 2010, which required balanced ventilation and preventive measures to reduce indoor radon levels, including a radon barrier toward the ground and pressure reducing features beneath the building that prevent soil gas from entering (radon sump). Investigations of randomly selected homes all across Norway have shown that houses built under these new regulations have significantly lower radon levels. However, a few municipalities in Norway are especially radon-prone and have houses with particularly high levels. It is crucial to verify the effect of the new regulations in these municipalities, which we have done in this study. Here, we show that both preventive radon measures and balanced ventilation and the building regulations of 2010 have significant effects on reducing the radon levels in the houses of the public. Noticeably for management, houses with a well-ventilated crawl space, which have been exempt from the required preventive measures, still in some cases have levels above action and maximum recommended levels


2022 ◽  
Vol 14 (2) ◽  
pp. 739
Author(s):  
Fernando del Ama Gonzalo ◽  
Matthew Griffin ◽  
Jacob Laskosky ◽  
Peter Yost ◽  
Roberto Alonso González-Lezcano

Several studies on indoor air quality (IAQ) and sick building syndromes have been completed over the last decade, especially in cold countries. Efforts to make homes airtight to improve energy efficiency have created buildings with low ventilation rates, resulting in the build-up of indoor pollutants to harmful levels that would be otherwise unacceptable outdoors. This paper analyzed the infiltration rates, indoor temperatures, and variations in CO2, 2.5 μm particulate matter (PM2.5), and total volatile organic compound (TVOC) concentrations over the fall of 2021 in several homes in New England, USA. A relationship between outdoor and indoor conditions and ventilation strategies has been set using the results from blower door tests and actual indoor air quality data. Although all case studies lacked mechanical ventilation devices, such as those required by ASHRAE Standard 62.2, natural ventilation and air leakage have been enough to keep VOCs and PM2.5 concentration levels at acceptable values most of the studied time. However, results revealed that 25% of a specific timeframe, the occupants have been exposed to concentration levels of CO2 above 1000 parts per million (ppm), which are considered potentially hazardous conditions.


2022 ◽  
Vol 12 (1) ◽  
pp. 441
Author(s):  
Anna Kubiak ◽  
Marcin Maćkiewicz ◽  
Marcin Karbarz ◽  
Magdalena Biesaga

Bisphenols are well-known endocrine disruptors that can easily migrate from plastic and can containers to food. Due to the complicated matrix and ultra-low concentrations of bisphenols in food, samples require extensive preparation before instrumental analysis. In this paper, an environmental sensitive microgel was employed as a sorbent for the preconcentration of four bisphenols, bisphenol A (BPA), bisphenol B (BPB), bisphenol E (BPE) and bisphenol F (BPF), from liquid food samples. Liquid chromatography with fluorescence detection (LC-FLD) was used for the quantification of bisphenols. By applying microgel solid-phase extraction procedure, the limits of detections achieved in liquid food samples can be lowered to 0.9 µg·L−1 for BPF and BPA, 2.3 µg·L−1 for BPE and 2.9 µg·L−1 for BPB. Only 5 mg of microgel was sufficient to achieve good recoveries (70.5–109%) with precision (RSD 0.21–5.01%, n = 3) for different analyzed liquid food samples spiked at concentration levels of 50 µg·L−1. In five out of twelve of the analyzed samples (pineapple, mandarin, peach, mushroom and pickles), they were contaminated with BPA, and the determined concentration was in the range of 6.2–22 µg·L−1; however, these results are below the specific migration limit (SML) set for BPA (50 µg·kg−1).


2022 ◽  
Vol 11 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Omar M. Elhady ◽  
Erian. S. Mansour ◽  
M. M. Elwassimy ◽  
Sameh A. Zawam ◽  
Ali M. Drar

Many of mimic analogues synthesized before depending on the change in the structure of aromatic rings. In this work, the carbonyl group in the structure of compounds 1-4 converted to thiocarbonyl group, and then studying the toxicological activity due to chemical change in the active center of mimic analogues was performed for compounds N-tert-butyl-2,4-dichloro-N'-(2,4-dichlorobenzoyl)benzohydrazide (2) and N-tert-butyl-2,4-dichloro-N'-[(2,4-dichlorophenyl)carbonothioyl]benzenecarbothiohydrazide (6). The toxicological study was done by using 2nd and 4th instar larvae of the cotton leaf worm, Spodoptera littoralis (Boisd.). Five concentration levels (600, 300, 150, 75 and 37.5 ppm) of compounds (2) and (6) were applied on the fresh plant food to the newly grown (2nd and 4th) instar larvae.


2021 ◽  
Vol 2 (2) ◽  
pp. 137-145
Author(s):  
Soemardiawan Soemardiawan ◽  
◽  
Hermansyah Hermansyah ◽  
Muhamad Salabi ◽  
Nurdin Nurdin ◽  
...  

Basically, in life, sport is a basic need for every human being at this time. Doing sports can prevent various diseases, including obesity, diabetes, cancer, injuries, and osteoporosis. In addition, exercise is also known to reduce stress and anxiety, improve sleep quality and concentration levels, and increase self-confidence. During the current Covid-19 pandemic, exercise can be an alternative in maintaining immune conditions. Therefore, this service activity aims to build public awareness about the healthy living movement through sports activities. Partners in this activity are residents of the Lingkar Permai community, RT 06, totaling 20 people. The activity method is through the transfer of knowledge and practice, while the steps are 1) counseling, 2) practice, 3) mentoring, and 4) evaluation. The results of the activities include 1) the understanding of partners has increased after counseling, the increase has reached 58.06%, and 2) partners can do simple movements taught by the team. Assistance activities still need to be carried out continuously so that people are genuinely aware of healthy living.


MEDISAINS ◽  
2021 ◽  
Vol 19 (3) ◽  
pp. 77
Author(s):  
Rohmayanti Rohmayanti ◽  
Widarika Santi Hapsari

Background: Centella asiatica L. Urban is a tropical plant whose spread is quite broad as Indonesia. One of the ingredients of Centella asiatica L. Urban is asiaticoside which has excellent wound healing abilities. However, research on diabetic wound healing with Centella asiatica L. Urban extract formulation in the form of a gel has not been found. Therefore, it is necessary to look at the healing activity of diabetic wounds using Centella asiatica L. Urban extract in the form of a gel.Objective: This experimental study aims to explore the effect of gel extract derived from the Centella asiatica L. Urban on the length of time for wound healing.Methods: The subjects in this study were eight weeks old Balb-C mice conditioned to hyperglycemia and were divided into five groups. The Centella asiatica L. Urban extract is provided in three concentration levels, with 3%, 5%, and 7%. As a form of negative control, used gel without Centella asiatica L. Urban extract and positive control without gel, only hydrocolloid dressing.Results: Centella asiatica L. Urban at concentrations of 3% (with the value of Sig. > 0.05), 5%, and 7% showed the ability to heal wounds.Conclusions: Centella asiatica L. Urban gel extract with a concentration of 3% had a significant effect on wound healing compared to other preparations.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Atinafu G/Mariam ◽  
Abebe Diro ◽  
Tsegaye Girma Asere ◽  
Demelash Jado ◽  
Fekadu Melak

Fluoride health problem is a great concern worldwide, most often as a result of groundwater intake. Thus, determination of fluoride is vital to take appropriate measures upon fluoride contamination of water. Potentiometric method of analysis is reliable for the determination of fluoride in various samples. In addition, spectroscopic methods are found important to quantify fluoride levels from water; however, several factors hinder its easier determination. Among the bottlenecks, the use of toxic chemicals and tedious steps in preparing chemicals (e.g., SPADNS method) are to mention a few. In this study, a spectrophotometric method was developed for the determination of fluoride from groundwater using Eriochrome Black T (EBT) as a spectroscopic reagent. Experimental parameters that influence the determination of fluoride including ligand type, kinetics, pH, and ligand-to-metal ratio were assayed. Evaluation of fluoride levels showed that Beer–Lambert’s law is obeyed in the range of 0.3–5.0 mg/L at 544 nm. The calibration curve, resulting in good linearity (R2 = 0.9997), was considered during quantitative analysis of the samples and in the spiking analysis. The limits of detection (LOD) and quantification (LOQ) of the method were found to be 0.19 and 0.64 mg/L, respectively. The precision studied in terms of intraday and interday at three concentration levels showed less than 5.4% RSD. Applicability of the method was investigated by analyzing groundwater samples spiked with fluoride standards, and satisfactory recoveries in the range of 98.18–111.4 were demonstrated. The developed spectrophotometric method has been successfully applied for fluoride determinations in groundwater samples. Thus, it could be used as an attractive alternative for the determination of fluoride from groundwater.


2021 ◽  
Vol 14 (1) ◽  
pp. 186
Author(s):  
Julia Martín ◽  
Carmen Mejías ◽  
Marina Arenas ◽  
Juan Luis Santos ◽  
Irene Aparicio ◽  
...  

Composting is an important waste management strategy, providing an economical and environment-friendly approach to sanitizing and stabilizing biosolids for land soil amendment. However, the resulting product can contain a large number of organic pollutants that may have adverse effects on the ecosystem. This paper presents the occurrence of eight widely used organic pollutants (four linear alkylbenzene sulfonates (LAS C10-C13), nonylphenol and its mono- and di-ethoxylates (NPE) and a di(2-ethylhexyl)phthalate (DEHP)) in full-scale composting processes. LAS homologues were detected at the highest concentrations (range of ∑LAS: 2068–9375 mg kg−1 dm), exceeding the limit fixed in the EU Directive draft. The concentration levels of the NPE and DEHP were significantly lower (up to 27.5 and 156.8 mg kg−1 dm, respectively) and did not exceed their fixed limits in the EU Directive draft. Ecotoxicological risk assessment for when compost is amended onto soils has also been evaluated. The concentrations measured represented a medium-low risk for most compounds, although it was not enough in the case of LAS C11 and C13 and NP.


2021 ◽  
Vol 2 (6) ◽  
pp. 43-48
Author(s):  
Manoah Muchanga ◽  
Henry M. Sichingabula

Dissolved and suspended sediment that form part of the Total Sediment Load (TSL) affects the quality of water making it unsuitable for selected aquatic invertebrates and livestock. The study aimed at determining spatial and seasonal dynamics in the concentration levels and distribution of selected physical parameters in a small lacustrine system whose main problem was punctuated by rapid deposition of clastic and none-clastic sediment. Water sampling was done during the rainy and cool-dry seasons across the reservoir using sampling bottles and DGPS. Laboratory analysis was done to determine variations in concentration levels of the parameters over time and space. Distributions of selected parameters across the reservoir were analysed using 3D Spatial Analysts Tool, Inverse Distance Weighted (IDW) in ArcGIS 10.2. Using paired T-Test at 0.05 level of significance, the study found statistically significant differences (p<0.001) in the concentration of TDS, TSS, and turbidity between the rainy season and cool-dry season. With exception of TDS, TSS and turbidity were higher in the rainy season than in the cool-dry season. Rainfall was the main control variable regarding seasonality influence on TDS, TSS, and turbidity. The study concluded that although lacustrine reservoirs may be closed systems, they still experience variations spatially and temporally in terms of concentration of TDS, TSS and turbidity. The study recommends implementation of integrated catchment-wide management of anthropogenic activities so as to minimize excess generation, transportation and deposition of sediment, which punctuate elevated levels of TDS, TSS and turbidity.


Sign in / Sign up

Export Citation Format

Share Document