Occurrence of polycyclic aromatic hydrocarbons in water and sediment samples from KwaZulu Natal Province,South Africa

Solid‐phase extraction (SPE) and ultrasonic extraction (UE) techniques followed by Gas Chromatography‐Mass Spectrometry (GC‐MS) have been modified for qualitative and quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples. Percentage recoveries of PAHs ranged from 85 to 121% in water and 82 to 117% in sediment samples. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.02 to 0.2 and 0.05 to 0.5 µg/L for SPE while for UE, they were between 0.008–0.09 and 0.02–0.30 µg/kg, respectively. The concentration levels of PAHs (naphthalene, acenaphthene, acenaphthylene, fluorine, anthracene, phenanthrene and pyrene) detected in water samples were 0.071–2.7, 2.0–10.4 and 2.5–3.5 µg/L in wastewater, river water, and dam water, respectively. In sediment samples, concentration levels of PAHs were between 2.8–42.0 and 2.8–3.9 µg/kg, in river and dam sediment, respectively.     

An analytical method for the analysis of trihalomethanes in ambient air using solid‐phase microextraction gas chromatography‐mass spectrometry: An application to indoor swimming pool complexes

A simple method for the collection and analysis of the four brominated and chlorinated trihalomethanes (THMs) in air samples is described. Ambient air samples were collected in pre‐prepared glass vials, with THM analysis performed using solid‐phase microextraction gas chromatography‐mass spectrometry, where the need for chemical reagents is minimized. Analytical parameters, including oven temperature program, solvent volume, incubation time, vial agitation, extraction time and temperature, as well as desorption time and temperature, were evaluated to ensure optimal method performance. The developed method allows for point‐in‐time quantification (compared to an average concentration measured over extended periods of time), with detection limits between 0.7 to 2.6 µg/m³. Excellent linearity (r² > 0.99), repeatability (3% to 11% RSD), and reproducibility (3% to 16% RSD) were demonstrated over a concentration range from 2 to 5000 µg/m³. The method was validated for the analysis of THMs in indoor swimming pool air and was used to investigate the occurrence of THMs in the air above 15 indoor swimming pools. This is the first study to report the occurrence of THMs in swimming pool air in Australia, and concentrations higher than those previously reported in other countries were measured.     

n‐Alkane distributions in soil and water samples collected near Agbabu bitumen field of southwestern Nigeria

Soil and water samples from the vicinity of Agbabu bitumen field of Southwestern Nigeria were analysed by GC‐FID for n‐alkanes, in order to characterize their distributions and to gather information on the degree of contamination by bitumen exploration and processing and other biogenic contributions. Total concentrations of n‐alkanes in water and soil samples analysed ranged from 61.5 to 472.7 µg L^?1 and 422.8 to 2289.4 ng g^?1 dw, respectively. On the basis of the total n‐alkane concentrations, carbon preference index (CPI) values and the odd‐even carbon predominance, it is suggested that both natural (e.g. aquatic input) and anthropogenic (e.g. bitumen and synthetics) sources contribute to the n‐alkanes load in soil and water samples of the area studied.     

Analysis of triclosan and 4n‐nonylphenol in Colombian reservoir water by gas chromatography‐mass spectrometry

In this work were determined triclosan and 4n‐nonylphenol in water from a reservoir that is used to provide water to a purification plant in an important city in Colombia. The analytical methodology was validated using solid‐phase extraction and analysis by gas chromatography‐mass spectrometry (GC‐MS). The analysis by GC‐MS showed good linearity in the range of 0.05–5 μg/L for both compounds. Recoveries from 79 to 109% and standard deviations of 2.5–7.7 for low concentrations and from 3.8 to 9.6 (n = 5) for high concentrations were obtained for both compounds. In Colombia, this is the first time that these compounds have been analysed in water supplying of a drinking water treatment plant. The validated method was applied to the analysis of 27 samples collected in August 2010 in 11 locations from the reservoir and in the influent and effluent of the drinking water treatment plant. In total, seven samples were found to contain triclosan.     

Biological and environmental exposure monitoring of volatile organic compounds among nail technicians in the Greater Boston area

Nail technicians are exposed to volatile organic compounds (VOCs) from nail products, but no studies have previously measured VOC biomarkers for these workers. This study of 10 nail technicians aimed to identify VOCs in nail salons and explore relationships between air concentrations and biomarkers. Personal and area air samples were collected using thermal desorption tubes during a work shift and analyzed using gas chromatography/mass spectrometry (GC/MS) for 71 VOCs. Whole blood samples were collected pre‐shift and post‐shift, and analyzed using GC/MS for 43 VOCs. Ventilation rates were determined using continuous CO₂ measurements. Predominant air VOC levels were ethyl methacrylate (median 240 µg/m³), methyl methacrylate (median 205 µg/m³), toluene (median 100 µg/m³), and ethyl acetate (median 639 µg/m³). Blood levels were significantly higher post‐shift than pre‐shift for toluene (median pre‐shift 0.158 µg/L and post‐shift 0.360 µg/L) and ethyl acetate (median pre‐shift <0.158 µg/L and post‐shift 0.510 µg/L); methacrylates were not measured in blood because of their instability. Based on VOCs measured in these seven nail salons, we estimated that emissions from Greater Boston area nail salons may contribute to ambient VOCs. Ventilation rates did not always meet the ASHRAE guideline for nail salons. There is a need for changes in nail product formulation and better ventilation to reduce VOC occupational exposures.     

Removal of tetracycline antibiotic by Lemna gibba L. from aqueous solutions

In this study, the efficiency of Lemna gibba L. on tetracycline (TC) removal from the solutions prepared at various initial TC concentrations (50, 100 and 300 µg/L) was investigated. The study was conducted in the reactors planted with Lemna gibba L. plants. Lemna gibba L. plants in the reactors were harvested at various hydraulic retention times. Then, the concentrations of TC were determined by using LC/‐MS‐MS. The maximum removal efficiencies for the TC50, TC100 and TC300 in the planted reactors were 99.8 ± 4.1; 99.9 ± 4.9 and 99 ± 4.9%, respectively. The harvesting times for Lemna gibba L. at TC50, TC100 and TC300 concentrations were determined to be 12, 8 and 12 hours, respectively. First‐, second‐ and pseudo‐first‐order kinetics are determined in the planted reactors (with Lemna gibba L.). According to the study results, second‐order kinetics were obtained at TC50, TC100, TC300 concentrations. As a result, the Lemna gibba L. plant can be used as an alternative treatment method to other advanced treatment methods and it can be done with a cheap method by adapting to existing treatment plants. Lemna gibba L. plants can be used to remove pollutants by applying them to polluted lakes and water bodies.     

Selenium bioaccumulation in eutrophic lake – Dąbie Małe Lake,Poland

While the world literature presents many studies on the occurrence of selenium in aquatic ecosystems, the risks associated with overexposure of hydrobionts to this element and the consequences of its magnification in the food chain (areas rich in Se), there are few studies on Se concentration in Poland's water bodies and watercourses (Se deficient area). The objective of the study was to assess the Se bioaccumulation in D?bie Ma?e Lake, based on Se concentration in the water, bottom sediments, and organs of Rutilus rutilus and Perca fluviatilis. The accumulation and biomagnification factor averaged 231 ± 69 and 1.2, respectively. Bioconcentration factor, calculated as Se in muscle divided by Se in water, ranged 35–104. Although Se concentrations in bottom sediments and fish were generally lower than the values reported in the literature, Se concentration in the water exceeded 2 µg/L, recommended value as a probable safe water concentration for wildlife.     

Nitrate removal from water using zero‐valent aluminium

Nitrate pollution in surface and groundwater is known to adversely affect human health, water quality and the health of aquatic ecosystems. Zero‐valent aluminium is a strong reductant for ions such as nitrate. In this study, its use in nitrate reduction efficiency was evaluated as a function of pH, aluminium dosage and aluminium particle size through a lab‐scale investigation. The most effective pH for complete nitrate removal, with an initial concentration of 14.0 ± 1.0 mg N/L, was found to be 13 ± 0.2. Under this condition, complete removal was achieved in 5 min, using aluminium particle size of 1–3 µm and aluminium‐to‐nitrate (NO₃^–‐N) ratio of 125. The 1–3 µm and 297–841 µm aluminium particles removed nitrate at a reaction rate constant (k) of 0.048 ± 0.017 (mg‐N/L)^1.53/min and at 0.042 ± 0.014 (mg‐N/L)^1.28/min, respectively. The use of smaller aluminium particles was found to be more effective for nitrate removal than large particles, and it was observed that for these particle sizes, aluminium dosages was less of a factor than any other experimental conditions evaluated.     

Graphene oxide nanosheets modified with trithiocyanuric acid for extraction and enrichment of Pb (II) and Cu (II) ions in seawater

Trithiocyanuric acid (TTC) is a robust chelating ligand for extracting divalent and univalent heavy metals from water samples. In this method, graphene oxide nanosheets (GO) was modified with TTC, to produce a new nano‐adsorbent (GO‐TTC), for extraction and preconcentration of Pb (II) and Cu (II) ions from seawater samples. The concentrated analytes were measured by a flame atomic absorption spectrometry. The detection limits of the method for Pb (II) and Cu (II) ions were 0.32 ng/mL and 0.13 ng/mL, respectively. The relative standard deviations of analytes for six successive extractions were below 1.64%. The maximum adsorption capacity of GO‐TTC for Pb (II) and Cu (II) ions was 750 µg/g and 460 µg/g, respectively. The recoveries of the spiked analytes in artificial and natural seawater samples were above 90%, pointing out that the method is not affected by the major coexisting ions in seawater matrices.     

Removal of selected risk elements from wastewater in a horizontal subsurface flow constructed wetland

Removal of Pb, Cd, Cr, Mo, V, Be and Ba from municipal wastewater using a horizontal subsurface flow constructed wetland was studied. The removal efficiencies attained for these elements were 50, 86, 71, 59, ?53, 37 and 40%, respectively. The average inflow and outflow Pb concentrations were 1.5 and 0.7 µg/L. Similarly, the inflow and outflow concentrations of 0.14 and 0.02 µg/L were obtained for Cd. Cr inflow and outflow concentrations were 3.7 and 1.1 µg/L, respectively. Concentrations of 0.78 and 0.32 µg/L were measured for Mo. V was washed out from the system. Its average inflow and outflow concentrations were 4.8 and 7.4 µg/L, respectively. Be inflow and outflow concentrations were rather low (1.03 and 0.65 µg/L), however, the concentrations of Ba were significantly higher (189 and 113 µg/L). The main perspective of the constructed wetland is the removal of toxic elements forming insoluble compounds (e.g. CdS) depositing in the wetland bed.     

Occurrence and seasonal variations of Giardia in wastewater and river water from Al-Jinderiyah region in Latakia,Syria

ABSTRACT

This study investigates the occurrence and concentration of Giardia cysts in wastewater and river water samples in Al-Jinderiyah region, Latakia, Syria. A total of 120 samples were collected between October 2016 and October 2017 from influent and effluent of Al-Jinderiyah Waste Water Treatment Plant (WWTP) and from three contaminated river water sites. Samples were concentrated and subjected to microscopic examination. The results show that the concentrations of cysts ranged from 0 to 297 cysts/L in wastewater samples. The overall removal efficiency of cysts in the activated sludge WWTP was 84.35%. The concentrations of cysts ranged from 0 to 128.52 cysts/L in river water samples. The highest concentration in river water was recorded near the raw wastewater discharge point. Seasonal variations of Giardia cysts concentration were significant, and the highest concentrations were recorded in the rainy season. The results suggest that Giardia may pose a public health risk in the studied region.     

Analysis of selected phthalates in Canadian indoor dust collected using household vacuum and standardized sampling techniques

Phthalates have been used extensively as plasticizers to improve the flexibility of polymers, and they also have found many industrial applications. They are ubiquitous in the environment and have been detected in a variety of environmental and biological matrices. The goal of this study was to develop a method for the determination of 17 phthalate esters in house dust. This method involved sonication extraction, sample cleanup using solid phase extraction, and isotope dilution GC/MS/MS analysis. Method detection limits (MDLs) and recoveries ranged from 0.04 to 2.93 μg/g and from 84 to 117%, respectively. The method was applied to the analysis of phthalates in 38 paired household vacuum samples (HD) and fresh dust (FD) samples. HD and FD samples compared well for the majority of phthalates detected in house dust. Data obtained from 126 household dust samples confirmed the historical widespread use of bis(2‐ethylhexyl) phthalate (DEHP), with a concentration range of 36 μg/g to 3840 μg/g. Dibutyl phthalate (DBP), benzyl butyl phthalate (BzBP), diisononyl phthalate (DINP), and diisodecyl phthalate (DIDP) were also found in most samples at relatively high concentrations. Another important phthalate, diisobutyl phthalate (DIBP), was detected at a frequency of 98.4% with concentrations ranging from below its MDL of 0.51 μg/g to 69 μg/g.     

Unexpected increase in indoor pollutants after the introduction of a smoke‐free policy in a correctional center

Correctional centers (prisons) are one of the few non‐residential indoor environments where smoking is still permitted. However, few studies have investigated indoor air quality (IAQ) in these locations. We quantified the level of inmate and staff exposure to secondhand smoke, including particle number (PN) count, and we assessed the impact of the smoking ban on IAQ. We performed measurements of indoor and outdoor PM_2.5 and PN concentrations, personal PN exposure levels, volatile organic compounds (VOCs), and nicotine both before and after a complete indoor smoking ban in an Australian maximum security prison. Results show that the indoor 24‐h average PM_2.5 concentrations ranged from 6 (±1) μg/m³ to 17 (±3) μg/m³ pre‐ban. The post‐ban levels ranged from 7 (±2) μg/m³ to 71 (±43) μg/m³. While PM_2.5 concentrations decreased in one unit post‐ban, they increased in the other two units. Similar post‐ban increases were also observed in levels of PN and VOCs. We describe an unexpected increase of indoor pollutants following a total indoor smoking ban in a prison that was reflected across multiple pollutants that are markers of smoking. We hypothesise that clandestine post‐ban smoking among inmates may have been the predominant cause.     

Phthalates in indoor dust in Kuwait: implications for non‐dietary human exposure

Phthalates are semivolatile organic compounds with a ubiquitous environmental distribution. Their presence in indoor environments is linked to their use in a variety of consumer products such as children's toys, cosmetics, food packaging, flexible PVC flooring among others. The goal of this study was to investigate the occurrence and concentration of phthalates in dust from homes in Kuwait and to assess non‐dietary human exposure to these phthalates. Dust samples were randomly collected from 21 homes and analyzed for eight phthalates. The concentrations of total phthalates were log normally distributed and ranged from 470 to 7800 μg/g. Five phthalates [Di(2‐ethylhexyl) phthalate (DEHP), Di‐n‐octyl phthalate (DnOP), Di‐n‐butyl phthalate (DBP), Benzyl butyl phthalate (BzBP), and Dicyclohexyl phthalate (DcHP)] were routinely detected. The major phthalate compound was DEHP at a geometric mean concentration of 1704 μg/g (median, 2256 μg/g) accounting for 92% of the total phthalates measured. Using the measured concentrations and estimates of dust ingestion rates for children and adults, estimated human non‐dietary exposure based on median phthalate concentrations ranged from 938 ng/kg‐bd/day for adults to 13362 ng/kg‐bd/day for toddlers. The difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors.     

Semi‐volatile organic compounds in the air and dust of 30 French schools: a pilot study

The contamination of indoor environments with chemical compounds released by materials and furniture, such as semi‐volatile organic compounds (SVOCs), is less documented in schools than in dwellings—yet children spend 16% of their time in schools, where they can also be exposed. This study is one of the first to describe the contamination of the air and dust of 90 classrooms from 30 nursery and primary schools by 55 SVOCs, including pesticides, phosphoric esters, musks, polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), phthalates, and polybromodiphenylethers (PBDEs). Air samples were collected using an active sampling method, and dust samples were collected via two sampling methods (wiping and vacuum cleaning). In air, the highest concentrations (median >100 ng/m³) were measured for diisobutyl phthalate (DiBP), dibutyl phthalate (DBP), diethyl phthalate (DEP), bis(2‐ethylhexyl) phthalate (DEHP), and galaxolide. In dust, the highest concentrations (median >30 μg/g) were found for DEHP, diisononyl phthalate (DiNP), DiBP, and DBP. An attempt to compare two floor dust sampling methods using a single unit (ng/m²) was carried out. SVOC concentrations were higher in wiped dust, but frequencies of quantification were greater in vacuumed dust.     

Artificial vs natural Stachybotrys infestation—Comparison of mycotoxin production on various building materials

The genus Stachybotrys belongs to filamentous fungi found in indoor environment, mostly on cellulose-rich substrates after water-damage. The major purpose of this study was to investigate the influence of different building materials in case of mold infestation on the mycotoxin production of Stachybotrys species. Fifteen Stachybotrys mycotoxins including satratoxins, phenylspirodrimanes, and recently discovered stachybotrychromenes were in the focus of the investigations. Artificial and natural infestations were compared to determine whether environmental factors, for example, time of growth, temperature, humidity, and material additives have an influence on the observed mycotoxin profiles. It turned out that mycotoxin profiles from Stachybotrys spp. on building materials can be influenced by cellulose, paints, and paste of the materials. The total toxin levels of artificially and naturally contaminated gypsum board samples ranged up to 30 µg/cm², whereas wallpaper samples showed total toxin levels in the range of 20-66 µg/cm². A naturally infested sample disclosed the conversion of the dialdehyde components to the corresponding lactone isomers under the influence of light.     

HPLC determination of polycyclic aromatic hydrocarbons (PAHs) in the littoral urban sewage area of cortiou (Marseille,France)

A selective method for determining polycyclic aromatic hydrocarbons (PAHs) in sediments using solid‐phase extraction and RP‐HPLC with fluorescence and UV detection is described. The complete analytical method is used to surface sediments from the creek of Cortiou (France). Sewage from the urban area of Marseille is delivered to the creek. PAH levels in sediments (µg/g) range between 2.251 µg/g (for the benzo(a)anthracene) and 相似文献   

A comparative study of walking‐induced dust resuspension using a consistent test mechanism

Human walking influences indoor air quality mainly by resuspending dust particles settled on the floor. This study characterized walking‐induced particle resuspension as a function of flooring type, relative humidity (RH), surface dust loading, and particle size using a consistent resuspension mechanism. Five types of flooring, including hardwood, vinyl, high‐density cut pile carpet, low‐density cut pile carpet, and high‐density loop carpet, were tested with two levels of RH (40% and 70%) and surface dust loading (2 and 8 g/m²), respectively. Resuspension fraction r_a (fraction of surface dust resuspended per step) for house dust was found to be varied from 10^?7 to 10^?4 (particle size: 0.4–10 µm). Results showed that for particles at 0.4–3.0 µm, the difference in resuspension fraction between carpets and hard floorings was not significant. For particles at 3.0–10.0 µm, carpets exhibited higher resuspension fractions compared with hard floorings. Increased RH level enhanced resuspension on high‐density cut pile carpet, whereas the opposite effect was observed on hard floorings. Higher surface dust loading was associated with lower resuspension fractions on carpets, while on hard floorings the effect of surface dust loading varied with different RH levels.     

Reactions in the aqueous environment of low molecular weight organic molecules

The origin of small organic molecules in surface waters of the United States, for the most part, stems from industrial, urban and agricultural sources. Agricultural materials were examined, particularly the chlorinated pesticides and herbicides, to determine concentration ranges within which the characteristic interactions of these solutes could be defined. It was found that chlorinated hydrocarbon concentrations of bottom sediments at selected locations range from 5 ng/kg (nanograms per kilogram) to 3.5 μg/kg (micrograms per kilogram), and in water from 5 ng/l to 0.06 μg/l. Herbicide concentrations in water ranged from 5 ng/l to 1.5 μg/l for the same samples. Total organic carbon concentrations at these locations ranged from less than 0.1 mg/l to 42 mg/l (milligrams per litre).     

Lead,Cadmium And Zinc Accumulation On Soil And Vegetation Along Some Selected Major Roads Of Eastern Cape

Surface soil and grass samples were collected in triplicates from seven locations perpendicular to three major roads in Eastern Cape. Total and available lead, cadmium and zinc were determined in the soil samples and total elements were determined in grass. Lead, cadmium and zinc concentrations declined with distance from road traffic. Significant correlation was also established between available elements in soil and in grass. Levels of total and available elements in the soils ranged from 1167-10834 v µg v g m 1 and from 200-" 5734 v µg v g m 1 , respectively. The levels of the element in grass varied between 200 v µg v g m 1 and 3900 v µg v g m 1 . Total and available cadmium levels in soil although lower than the levels are also significant with values ranging from 17-"2833 v µg v g m 1 and from 27 v µg v g m 1 and from 27-1867 v µg v g m 1 , respectively. The cadmium levels in grass varied between 7 v µg v g m 1 and 1100 v µg v g m 1 . The total and available zinc levels in soil ranged from 2833-8334 v µg v g m 1 and from 533-3600 v µg v g m 1 . The levels in grass varied between 0 and 2800 v µg v g m 1 . The degree of pollution measured would constitute a threat to livestock. Motor traffic appears to be the main source of the elements.