Assessment of heavy metals contamination and its effects on oyster (Saccostrea cucullata) biometry parameters in the Asaluyeh port coasts,Persian Gulf,Iran

The current study examines biometric parameters and concentration of some heavy metals in soft tissues of Saccostrea cucullata in the Asaluyeh coast, Persian Gulf, Iran. The metals concentration in the soft tissue of the Saccostrea cucullata ranged as: Zn: 765–3411 mg kg^?1, Cu: 120.3–580.6 mg kg^?1, Cd: 0.13–3.5 mg kg^?1, As: 0.39–3.3 mg kg^?1, Pb: 0.05–1.64 mg kg^?1, Ni: 0.02–0.44 mg kg^?1, V: 0.06–0.32 mg kg^?1, Cr: 0.02–0.16 mg kg^?1 and Hg: 0.002–0.068 mg kg^?1. The results showed that the concentration of total heavy metals in oysters of the control station (CA) is usually lower. The results also indicated lack of correlation between oyster biometric parameters and bioaccumulated heavy metals, except between Cu and longitudinal diameter (R = 0.77). The concentration of heavy metals is higher than limits recommended by the World Health Organization, except for Cd and Pb.     

Evaluation of the effects of greywater reuse on domestic wastewater quality and quantity

This simulation study, based on experimental and literature data, evaluates the influence of onsite greywater reuse on domestic wastewater quality and quantity. For this, three scenarios were studied: no reuse; reuse for toilet flushing; reuse for toilet flushing and garden irrigation. Light greywater reuse reduced the daily household wastewater flows by 25–40%. These reductions mainly occurred during the morning and evening peak wastewater generation. Although daily loads of all pollutants decreased, their concentrations in the discharged wastewater increased owing to exclusion of potable water from the wastewater and replacing it by treated light greywater. The proportional concentration increase of most pollutants was lower than the decrease in wastewater discharge, due to degradation during treatment. The highest concentration increase occurred during the morning peak, coinciding with the highest flow reduction. This study is a first step towards quantification of the effects of onsite greywater reuse on sewers and wastewater treatment plants.     

Presence and fate of priority substances in domestic greywater treatment and reuse systems

A wide range of household sources may potentially contribute to contaminant loads in domestic greywater. The ability of greywater treatment systems to act as emission control barriers for household micropollutants, thereby providing environmental benefits in addition to potable water savings, have not been fully explored. This paper investigates the sources, presence and potential fate of a selection of xenobiotic micropollutants in on-site greywater treatment systems. All of the investigated compounds are listed under the European Water Framework Directive as either “Priority Substances” (PS) or “Priority Hazardous Substances” (PHS). Significant knowledge gaps are identified. A wide range of potential treatment trains are available for greywater treatment and reuse but treatment efficiency data for priority substances and other micropollutants is very limited. Geochemical modelling indicates that PS/PHS removal during treatment is likely to be predominantly due to sludge/solid phase adsorption, with only minor contributions to the water phase. Many PS/PHS are resistant to biodegradation and as the majority of automated greywater treatment plants periodically discharge sludge to the municipal sewerage system, greywater treatment is unlikely to act as a comprehensive PS/PHS emission barrier. Hence, it is important to ensure that other source control options (e.g. eco-labeling, substance substitution, and regulatory controls) for household items continue to be pursued, in order that PS/PHS emissions from these sources are effectively reduced and/or phased out as required under the demands of the European Water Framework Directive.     

Quantifying spatial-temporal changes of aboveground carbon stocks using Landsat time series data: A case study of Miombo woodlands

ABSTRACT

There is a need for accurate reporting of the second-growth forest in accounting for the contribution of secondary forests to achieving global carbon sequestration strategies. This study develops a model relating aboveground live biomass (AGLB) to Landsat reflectance measurements, and this method is used on multi spatial-temporal Landsat data (1998, 2001, 2004, 2011 and 2016) to assess changes in Miombo woodlands in Zambia. Results showed that the enhanced vegetation index was a better predictor of AGLB (r² = 0.96; RMSE = 0.24 t ha^?1) than the other assessed vegetation indices. Forest carbon stocks increased by an average rate of 3.65 ± standard error (SE): 0.56 t ha^?1 yr^?1 from 1998 to 2001, but a continual decline was evident for the periods 2001–2004 (?0.60 t ha^?1 yr^?1), 2004–2011 (?0.88 t ha^?1 yr^?1) and 2011–2016 (?2.03 t ha^?1 yr^?1). The study provides an empirical model for evaluating carbon stock changes.     

Geohydrological properties of selected badland sediments in Saskatchewan,Canada

Geological and seasonal weather variations govern the geohydrological properties of the Avonlea badlands in Saskatchewan, Canada. Three surface sediments exhibiting distinct lithologic variations were found: a steeply sloped and fissured sandstone; a mildly sloped and popcorn-textured mudrock; and a flat and eroded pediment. The fines content increased from the dry to the wet state, with contents of 17–33 % seen for sandstone, 4–98 % for mudrock, and 21–42 % for pediment. The water adsorption capacity was found to be highest for mudrock (w _l = 96 % and w _p = 47 %), followed by sandstone (w _l = 39 % and w _p = 31 %), and then by pediment (w _l = 31 % and w _p = 23 %). The soil water characteristic curves of sandstone and mudrock showed bimodal distributions with a low air entry value (6 and 9 kPa) pertaining to drainage through cracks and a high air entry value (160 and 92 kPa) associated with flow through the soil matrix. The pediment presented a unimodal soil water characteristic curve with a single matrix air entry value of 4 kPa. The saturated hydraulic conductivities for sandstone, mudrock, and pediment were measured as 8.5 × 10^?6, 4.0 × 10^?8, and 1.8 × 10^?5 m/s, respectively.     

Mn and Ni contents in soils of a qualified denomination of origin region: Rioja D.O.Ca,Spain

The distribution of Mn and Ni in soils of one of the most famous winegrowing regions of Spain, Rioja D.O.Ca (Denomination of origin, Spain's top category), was studied in detail according to its geographical location. There were background concentrations of 288.81 mg kg^?1 total Mn in the surface horizon and 296.06 mg kg^?1 in the subsoil; and a total Ni content of 17.89 mg kg^?1 in the surface horizon and 24.76 mg kg^?1 in the subsoil. The amounts of Mn bio- or phytoavailable were 5.28 mg kg^?1 in the upper horizon and 4.70 mg kg^?1 in the subsurface horizon; and for Ni bio- or phytoavailable, the amounts were 0.14 mg kg^?1 in the upper horizon and 0.13 mg kg^?1 in the deeper horizon. Spatial distribution patterns were established using GIS contour maps for the two elements, showing significant variations within and between the sites. The local contamination is generally associated with the quantities that are added to the soil or water from man-made sources such as industrial discharge and volatile emissions, sewage sludge, livestock wastes and other wastes.     

Dégradation des eaux de rejets issues d’une raffinerie d’huile de coton par plasma d’arc électrique rampant à pression atmosphérique

Wastewater samples from liquid effluents of cotton oil refinery in Far-Northern Cameroon were exposed to a gliding arc discharge for various exposure times in a cold plasma reactor. The analysed results showed high levels of organic pollution parameters (TOC = 4635 mg/L, COD = 6943, 98 mg/L) before treatment. More than 56% TOC and 75% COD abatement were obtained after 30 min treatment in batch conditions with a laboratory reactor. The resultant pollution abatement is attributed both to strong oxidizing effects of °OH and NO° radicals formed in the plasma and their derivatives (H₂O₂, ONO₂H and NO₃H). The conductivity and TDS increase linearly and the pH, TOC and COD decrease with increasing exposure time to the discharge. The oxidation obeys a pseudo first-order kinetics law (kinetic rate: k_1DCO = 0, 0381 min^?1 and k_1COT = 0, 0245 min^?1).     

Radioactive element contents of some granites used as building materials: insights into the radiological hazards

This study was conducted to investigate the radioactive potential hazard of granite, which is widely used as building material in Turkey. Natural radiation levels of 18 various, globally-distributed industrial granite samples imported by Turkey, were analyzed using gamma-ray spectrometer. The results are compared with the formerly published findings of granite samples from Turkey. Radioactivity levels of ²³⁸U, ²³²Th, and ⁴⁰K natural radioactive series elements of the selected 18 specimens were measured, which were from 2.4 ± 0.5 to 88.8 ± 3.6 Bq kg^?1 for ²³⁸U, from 2.4 ± 0.7 to 273 ± 0.9 Bq kg^?1 for ²³²Th, and from 169 ± 24 to 1,479 ± 94 Bq kg^?1 for ⁴⁰K. Radium equivalent activities (Ra_eq) were calculated for the granite samples to assess their radiation hazards in the construction of dwellings. The Ra_eq values of granite samples varied in the range of 39.05–570 Bq kg^?1, only one sample exceeded the safe limit value of 370 Bq kg^?1 set by the OECD-NEA (Nuclear Energy Agency. Exposure to radiation from natural radioactivity in building materials. Report by NEA Group of Experts 1979). Absorbed dose rates in air were found between 18.74 and 261 nGy h^?1 and radiogenic heat production values were calculated in the range of 0.45–6.53 μW m^?3. All rock samples used in this study were also analysed mineralogically and defined their compositions.     

Formation and properties of sediments in constructed wetlands for treatment of domestic wastewater

Sediments formation and biogeochemical properties were studied in an experimental constructed wetland site in Ukraine (“Bioplato”) for treatment of domestic effluents. The wetland, with a capacity of 50 m³ d^? 1 of wastewater, consists of vertical and horizontal filtrations units with fine gravel, middle and coarse sand, a subsurface flow unit with natural wetland soil applied, and a septic tank and sludge-drying field. Macrophytes, reed (Phragmites australis), cattail (Typha latifolia) and a number of sedge species (Carex spp.) were planted in the area and dominate the average cover of 85–90%. Treatment efficiency for BOD₅ and suspended solids was 93–96%, for COD – 82%, for nutrients – 27–50%, and for pathogenic microorganisms 99.3–99.6%. Sludge was sampled at each unit followed by standard laboratory analyses of its main characteristics: total organic carbon (TOC), total nutrients (N, P), contents of trace elements, abundance of pathogenic microorganisms, and general toxicity. Results confirmed that the top layer of sludge from each unit of wetland could be used as a source of fertilizers for grain and leguminous crops.     

Contribution of domestic effluents to hydrocarbon levels of dry weather flow in combined sewers

The importance of hydrocarbon contamination of the sewer network has been reported by many authors recently. Most of the studies are focused on the introduction of such pollutants into combined sewers by street and roof stormwater, but few evaluate the contribution of domestic inputs to hydrocarbon pollution. As a consequence, this work—carried out on the framework of the OPUR (Observatory of Urban Pollutants) research program—assesses the resolved aliphatic (AH), unresolved complex mixture (UCM) and polycyclic aromatic hydrocarbon (PAH) concentrations of domestic effluents (DE) and evaluates the role played by such effluents on the hydrocarbon levels of dry weather flow (DWF) in combined sewers. Results show hydrocarbon concentrations in the 200 – 300 μg · l^?1, 300 – 1 000 μg · l^?1 and 0.9 – 1.4 μg · l^?1 ranges for AHs, UCM and the 16 PAHs of the US-EPA, respectively. The assessment of hydrocarbon fluxes conveyed by domestic effluents on the scale of the ‘Le Marais’ experimental urban catchment (42 ha, centre of Paris) reveals the predominant contribution of domestic inputs to the DWF pollution and highlights the unsuspected role of households.     

Spectrophotometric determination of nickel using a new chromogenic reagent in plant leaves

A Spectrophotometric method for the determination of nickel in plant leaves with new chromogenic reagent is presented. A new highly sensitive and selective chromogenic reagent dibromo‐p‐methyl‐carboxyazo was synthesized; in 0.25 M phosphoric acid medium, which greatly increases the selectivity. Nickel reacts with DBMCA to form a 1:2 mole‐ratio bluish red complex, having a sensitive absorption peak at 625 nm under optimal conditions. Beer's law is obeyed over the range from 0.01 to 0.79 µ mL^? Ni (II) and the apparent molar absorptivity is 1.038?×?10^??4 mol^??1 cm^??1. The detection limit and variation coefficient were found to be 2.12 ng mL^??1 and 1.0% respectively. It is found that, except for Ca (II) and Ba (II), all foreign ions studied do not interfere with determination. The interference caused by Ca(ll) and Ba(ll) can be easily eliminated by prior extraction with potassium iodide methyl isobutyl ketone. The method has been applied to the determination of nickel in plant leaves with good accuracy.     

Comparison of the Combustion of Pine Species with Two Sizes of Calorimeter: 10 g vs. 100 g

This study aims to analyze the scale effects on the combustion dynamics and smoke emitted during the burning of vegetation species under laboratory conditions. Experiments were carried out at two scales of combustion with two fuels (Pinus pinaster and Pinus laricio needles). Two oxygen consumption calorimetry devices were used: the cone calorimeter with samples in the scale of 10 g, and Large Scale Heat Release rate calorimeter (LSHR) with samples in the scale of 100 g. Fuel loads of 1.2 kg m^?2 and 1.04 kg m^?2 were considered respectively for Pinus pinaster and Pinus laricio needles. The parameters investigated to analyze the combustion dynamics are the heat release rate, combustion efficiency and mass loss rate. Measuring the extinction coefficient allowed us to obtain the soot emission factor. The emission factors of the combustion gases were obtained by using FTIR and NDIR detectors. A carbon mass balance showed that more than 95% of carbon was recovered. This study revealed an effect of scale on the combustion dynamics (peak HRR of 806 kW m^?2 and 651 kW m^?2 respectively at the bench scale and at full scale for Pinus pinaster), total smoke production, soot emission factor (1.32 g kg^?1 and 5.17 g kg^?1 respectively at the bench scale and at full scale for Pinus pinaster) and nitrogen compounds emission factors (2.47 g kg^?1 and 5.25 g kg^?1 for the NO respectively with the cone calorimeter and LSHR for Pinus laricio). Combustion efficiency appeared to be largely independent of the combustion scale (96.89% and 96.61% respectively at the bench scale and at full scale for Pinus pinaster). We also observed differences in the fire behavior for both types of needles.     

Raumzeitmuster des See-Grundwasser-Austausches in einem sauren Tagebaurestsee

Water quality of acid mine lakes is strongly affected by groundwater inflow from the mine tailings. The rate of inflow can be an important control on the release of acidity at the lake-groundwater interface. A robust quantification of exchange fluxes is therefore of paramount importance for the chemical evolution of the lakes. The spatial and temporal patterns of lake-groundwater exchange in an acid mine lake from open pit lignite mining in Lower Lusatia, Eastern Germany were investigated using seepage meter measurements at 16 locations. To validate exchange rates from the seepage meters, additional flux estimates were obtained from hydraulic gradients, hydraulic conductivities and vertical chloride profiles. The different methods compared well and revealed strong spatial and temporal variability of exchange. In contrast to previous studies (Knoll et al. 1999), the general pattern of exchange is currently characterized by groundwater inflow at the north end of the lake and outflow of lake water to the aquifer in the south. Exchange rates ranged from –1.7?l?m^–2?d^–1 (outflow) to > 200?l?m^–2?d^–1 (inflow). The highest rates of inflow were observed at local hot spots in the deeper part of the lake and are explained by local hydraulic connections with the underlying Tertiary aquifer. The general spatial pattern is controlled by the regional groundwater flow field. Temporal patterns are the result of transients in the hydrologic boundary conditions (lake and groundwater levels), which, depending on the connectivity between the lake and parts of the aquifer-system, affect exchange fluxes to different degrees.     

A decade’s (2014–2024) perspective on cassava’s (Manihot esculenta Crantz) contribution to the global hydrogen cyanide load in the environment

In recent years, developing countries have increased their cassava (Manihot esculenta) production for food security. Cassava contains cyanogen glycosides, mainly as linamarin, which through bio-catalysis, i.e. enzyme hydrolysis, results in hydrogen cyanide (HCN). HCN is released into the environment through numerous ways with subsequent volatilisation. Thus, the HCN released during the period 2002–2013 was estimated between 0.025?×?10^?3 to 6.71 ppq (African), 0.012?×?10^?3 to 1.01 ppq (Asian) and 0.007?×?10^?3 to 0.920?×?10^?3 ppq (South American). Furthermore, a decade’s (2014–2024) projection of HCN volatilisation displays increases of 60.5% (Africa), 57.7% (Asia) and 50.5% (South America) when compared with the current production. Furthermore, gas released during cassava plants’ growth, i.e. HCN, NH₃, and NO₂, was quantified in healthy plants. Varying concentrations of HCN were released. These further indicated the presence of a pseudo-halogenic gas in the environment – a contributor to climate change.     

Seasonal patterns and socio-economic predictors of household rainwater and greywater use

Seasonal water insecurity is a growing concern in many countries. For some households, rainwater and greywater are important alternative water sources. This study examines household patterns and socio-economic predictors of using rainwater and greywater in urban Philippines, in rainy versus dry seasons. Results from a household survey (N = 396) and in-depth interviews (N = 18) suggest that rainwater and greywater use are widespread, particularly among households with more members, less financial resources, and less access to the public utility, in seasonal ways. Future research into the adoption and diffusion of these practices may inform policies that promote equitable water access year-round.     

Influence of mineral precipitation on the performance and long-term stability of Fe 0 -permeable reactive barriers: A review on the basis of 19 Fe 0 -reactive barrier sites

A comparative evaluation of the monitoring results from 19 Fe⁰-permeable reactive barriers (PRBs) is presented which considers changes of groundwater composition within the Fe⁰-PRBs, the type and distribution of mineral phases that precipitate, porosity reductions, extent of the load of inorganic groundwater constituents and the overall performance. The findings show that the changes in groundwater composition within the PRBs are extremely similar, independent of flow velocities, residence times, and concentrations of inorganic substances. In addition, the type and distribution of mineral precipitates do not show great variances with the largest mineral accumulations within the first 10 to 30 cm from the entrance face of the PRBs. From these comparisons it can be concluded that loads of dissolved inorganic species higher than 200 kg?·?a^–1?·?m^–2 limit the long-term performance of Fe⁰-PRBs up to a few years due to porosity losses caused by mineral precipitation, independent of the type of construction. Moreover, detailed calculations of porosity and hydraulic conductivity decreases of the PRBs at the Rheine and Tübingen sites show that the influence of mineral fouling on the hydraulic permeability of a PRB can only be estimated by accounting for the interaction between reduction in porosity, permeability and flow rate. The findings suggest that it is possible to pre-estimate the porosity and permeability development for a potential PRB.     

Long-term performance and binder chemical structure evolution of elastomeric bituminous geomembranes

This paper presents the results of uniaxial tensile tests, flow-rate measurements, and size-exclusion chromatography (SEC), which are used to evaluate the ageing of elastomeric bituminous geomembranes (BGMs) that were installed 6, 10, 15, 20, and 30 years ago in ponds at two different sites in France. SEC was used to detect oxidation and the absence of polymer in the bitumen at the surface of the 20- and 30-year-old BGMs. The results indicate that, for BGMs exposed less than 20 years, there was no oxidation or degradation of the polymer at the core. However, the elastomeric polymer was altered at the core of the 30-year-old BGM, resulting in an embrittlement of the bitumen, but this did not affect the mechanical properties of the glass veil and nonwoven polyester geotextile in the BGM core. Lastly, the flow rates through the BGM measured according to EN 14150 are still below 10^?6 m³ m^?2 d^?1, which indicates that the elastomeric bituminous GM is still watertight after 30 years of exposure.     

Study on swelling properties of an expansive soil deposit in Saskatchewan, Canada

The main objective of this paper was to study the swelling properties of Regina clay. The deposit comprises a topsoil (surface to 0.3 m depth), an expansive clay (0.3–8 m), and a bottom till (8–9 m). High liquid limit (70 ± 15 %) and plastic limit (33 ± 4 %) indicated high water retention and adsorption capacity for the clay. Irrespective of the cover type (vegetation and cracked road), the field water content in summer closely matched the plastic limit. The clay was characterized by medium-to-high swelling that was best predicted by SP = 0.16 (I _p)^1.188. The soil had 51 % clay minerals including smectite (32 %), illite (7 %), kaolinite (5 %), and chlorite (3 %). With a CEC of 40 cmol(+)/kg, Ca²⁺ and Mg²⁺ were found to be the main exchangeable cations: the specific surface area was 50 m²/g. The SP and P _s for a 1.2 m deep sample measured 12 % and 260 kPa, respectively, and the estimated surface heave of 180 mm gradually diminished to 3.6 m depth. These values matched well with consistency-based correlations.     

Performance assessment of empirical models for prediction of daily and monthly average global solar radiation: the case study of Ibadan,Nigeria

In this study, the performance assessment of empirical models for modelling global solar radiation in Ibadan is presented. The empirical models are derived from the three basic models: Angstrom–Prescott model, Garcia model and Hargreaves–Sammani model. The data used in the analysis consist of daily average global solar radiation, daily average sunshine hours, daily average maximum temperature and daily average minimum temperature collected over a period of nine years (2000–2008). Regression constants are determined for each of the model for each months of the year. The study reveals that Garcia Quadratic model puts up the best overall performance. The model can predict the daily average global solar irradiation with Mean Absolute Error of 1.86?MJ?m^?2?day^?1, Root Mean Square Error of 2.7?MJ?m^?2?day^?1, Mean Absolute Percentage Error 9.34% and Coefficient of Determination (R²) of 0.68.     

Environmental Gamma radiation measurement using TLDs around TNRC,tripoli

The outdoors absorbed dose rate in the air around the Tajoura nuclear research centre (TNRC), Tripoli has been measured. The measurements were performed using calcium fluoride dysprosium (CaF₂: Dy) thermoluminescence dosimeters (TLD‐200) at 9 locations, all 1 m above the ground level.

The average outdoors absorbed dose rate in air, effective dose and the collective effective dose were calculated to be 54?±?4.6 nGyh^??1, 66.23 μSvy^??1 and 99.35 manSvy^??1, respectively, based on the analysis of thermoluminescence dosimeters data.