Chemical Fractionation Research Articles

Effects of Biochar on Arsenic-Contaminated Soil: Chemical Fractionation, Vegetation Growth, and Oral Bioaccessibility.

Contamination by arsenic (As) is a pressing environmental and public health issue requiring urgent remediation strategies. One cost-effective and eco-friendly method involves adding stabilizing agents to soils to reduce As mobility. However, remediation projects must also address potential ecotoxicological effects. These effects may include harmful impacts on both aquatic and terrestrial organisms, including plants, disruption of ecosystem balance, and the potential bioaccumulation of toxic substances in the food chain. Biochar from organic fraction of municipal solid waste (OFMSW) shows promise for As-contaminated soil remediation. Pot experiments were conducted with soil contaminated with As (100 mg kg-1) and amended with biochar produced at three different temperatures (300, 500, and 700 °C) and addition rates (1 and 5%, w/w). Chemical fractionation showed higher As concentration in a less accessible fraction (F4). Biochar amendments did not significantly differ from the control in As immobilization, but enhanced maize (Zea mays) growth and reduced As uptake, with the most promising results seen with 1% of biochar produced at 700 °C. The bioaccumulation factor (BCF) and translocation factor (TF) were both lower than 1, indicating a low absorption of As and minimal translocation from the root to the shoot. The bioaccessible percentage was higher in the samples treated with biochar compared to the control. According to the results, biochar showed no satisfactory potential for As immobilization and its approach of pretreatment/modification should be tested regarding possible improvements in the immobilization performance of As. Since most contaminations involve multiple contaminants simultaneously, it is essential to test the interactions between arsenic and other pollutants to understand the effects of biochar in such complex scenarios, which will be explored in future studies. Graphical abstract.

Analysis of the Organic Chemical Fractions of Three Coal Extracts

Analysis of the Organic Chemical Fractions of Three Coal Extracts

A new measurement of the Galactic 12C/13C gradient from sensitive HCO+ absorption observations

We present a new constraint on the Galactic 12C/13C gradient with sensitive HCO+ absorption observations against strong continuum sources. The new measurements suffer less from beam dilution, optical depths, and chemical fractionation, allowing us to derive the isotopic ratios precisely. The measured 12C/13C ratio in the solar neighborhood (66±5) is consistent with those obtained from CH+. Two measurements toward the GC are 42.2±1.7 and 37.5±6.5. Though the values are a factor of two to three higher than those derived from dense gas tracers (e.g., H2CO, complex organic molecules) toward Sagittarius (Sgr) B2 regions, our results are consistent with the absorption measurements from c-C3H2 toward Sgr B2 (~40) and those from CH+ toward Sgr A* and Sgr B2(N) (>30). We have calculated a new Galactic 12C/13C gradient of (6.4±1.9)RGC/kpc+(25.9±10.5) and found an increasing trend of the 12C/13C gradient obtained from high-density to low-density gas tracers, suggesting that opacity effects and chemical fractionation may have a strong impact on the isotopic ratios observed in high-density regions.

Carbon Stock and Chemical Fractionation of Organic Matter in Different Soil Management Systems in the Bahian Cerrado

ABSTRACT Determining total organic carbon and its stock and quantifying the chemical fractions of soil organic matter can be used as indicators of the quality of the soil management used in a cropping area. This study aimed to quantify soil organic matter’s carbon stock and chemical fractions in different soil management systems used in the western Bahian Cerrado, Brazil, and compare them to a native Cerrado area. Ten microregions (Alto Horizonte, Anel da Soja, Bela Vista, Cascudeiro, Coaceral, Novo Paraná, Panambi, Placas, Roda Velha, Roda Velha de Baixo), three soil management systems [tillage system (TS), no-tillage systems (nTS), native Cerrado (NC)], and two soil layers (0–0.1 and 0.1–0.2 m) were studied. Soil bulk density (Sd), soil organic matter (SOM), total organic carbon (TOC), SOM quantification (qSOM), equivalent carbon stock (EqCs), humin (HF), humic acid (HAF) and fulvic acid (FAF) fractions from SOM were evaluated. The results indicated that Sd in all evaluated microregions was below the critical upper limit that would restrict plant root development. SOM, TOC, EqCs, and qSOM revealed increasing results following the TS, nTS, and NC order. The NC area presented the highest soil organic fraction contents (HF, HAF, and FAF). The microregions with better soil quality for all evaluated parameters were Coaceral and Cascudeiro; the lowest soil quality was observed in Alto Horizonte. The present study indicates that conservation agricultural management, such as the no-tillage system, improves the structure and composition of SOM parameters over time.

Source-risk and uncertainty assessment of trace metals in surface sediments of a human-dominated seaward catchment in eastern China

Current total concentration-based methods for source attribution and risk assessment often overestimate metal risks, thereby impeding the formulation of effective risk management strategies. This study aims to develop a framework for source-specific risk assessment based on metal bioavailability in surface river sediments from a human-dominated seaward catchment in eastern China. Metal bioavailability was quantified using chemical fractionation results, and source apportionment was conducted using the positive matrix factorization (PMF) model. Risk assessment integrated these findings using two indices: the Potential Ecological Risk Index (PERI) and the Mean Probable Effect Concentration Quotient (mPEC-Q), with uncertainty addressed via Monte Carlo simulations. Results indicated that average total concentrations of Cu, Pb, Zn, Cr, Hg, Cd, and As exceeded their respective background levels by 1.63 to 15.00 times. The residual fraction constituted the majority, accounting for 53.84 % to 77.79 % of total concentrations, suggesting significant natural origins. However, source apportionment revealed a predominant contribution from anthropogenic activities, including industrial smelting, agricultural practices, and atmospheric deposition. The contributions were found to vary between 5.35 % and 40.03 % when the total concentration was adjusted to bioavailable content. Total concentration-based PERI/mPEC-Q assessments indicated high/moderate risk levels, decreasing to considerable/low risk levels with bioavailability adjustment. Hg and Cd were identified as priority metals. Further incorporating source appointment parameters into the risk assessment, industrial smelting was identified as the primary contributor, accounting for 66.06 % of total risk by total concentration and 65.63 % by bioavailability. This underscores the role of bioavailability in mitigating risk overestimation. Monte Carlo simulations validated industrial smelting as a major risk contributor. This study emphasizes the importance of considering bioavailability in the source-risk assessment of sediment-metals, crucial for targeted risk management in urbanized catchment areas.

A variational framework for Cahn–Hilliard-type diffusion coupled with Allen–Cahn-type multi-phase transformations in elastic and dissipative solids

This article presents a variational framework for coupled chemo-mechanical solids undergoing irreversible micro-structural changes at infinitesimal strains. The coupled problem is characterised by phenomena such as phase transitions, micro-structure coarsening and swelling. It is an extension of our previous work on variational inelasticity for a conserved chemo-mechanical setting to a unified conserved and non-conserved setting which include multi-phase transformations. The variational framework, again governed by continuous-time, discrete-time and discrete-space–time incremental variational principles, is outlined for coupled diffusion-phase transformation phenomena in elastic and dissipative solids. For the sake of simplicity, focus is restricted to isothermal conditions. It is shown that the governing macro- and micro-balance equations of the coupled problem appear as Euler equations of these minimisation and saddle point principles. In contrast to our previous work, extended variational principles (with the gradient of the chemical potential and phase fractions) are constructed that account for diffusion-phase transformation coupling. This is achieved by Legendre transformations. Note that the local–global solution strategy is still preserved and the resulting system of symmetric non-linear algebraic equations are solved by Newton–Raphson-type iterative methods. The applicability of the proposed framework is demonstrated by numerical simulations that qualitatively characterise lower bainitic micro-structure.

Chemical Fractions and Magnetic Simulation Based on Machine Learning for Trace Metals in a Sedimentary Column of Lake Taihu

In this study, the chemical fractions (CFs) of trace metal (TMs) and multiple magnetic parameters were analysed in the sedimentary column from the centre of Lake Taihu. The sedimentary column, measuring 53 cm in length, was dated using 210Pb and 137Cs to be 124 years old. Surface layers of the column were found to contain significantly higher concentrations of Cd, Co, Cu, Pb, Sb, Ti, and Zn than the middle and bottom layers. The sedimentary core contained a substantial amount of ferrimagnetic minerals. Most of the TMs were present in the residual state, except for Mn and Pb. The chemical fractions of Cd exhibited the most significant variation with depth. The pollution load index (PLI) indicated moderate TMs pollution levels in the region, whereas the risk assessment code (RAC) classified Mn as being heavily polluted. Multiple linear regression (MLR) and random forest (RF), support vector machine (SVM), and XGBoost (1.7.7.1) machine learning models were used to simulate the RAC and total concentration of TMs, using physical and chemical indicators and magnetic parameters of the sediments as input variables. The MLR model outperformed RF, SVM, and XGBoost in simulating the CFs and total concentrations of most TMs in the sedimentary column, with R2 up to 0.668 and 0.87. The SHapley Additive exPlanations (SHAP) method reveals that χarm/χ is the dominant factor influencing the RAC of As in the XGBoost models. For the RAC of Co and Cu in RF models, C% and N% exhibit greater contributions.

Contamination, fraction, and source apportionment of heavy metals in sediment of an industrialized urban river in China

In this study, we conducted an analysis of the heavy metal concentrations, health risk assessment, fraction and source interpretation in surface and core sediments from main stream of the Pearl River and Pearl River Estuary (RRE) area. Results showed that the higher deposited heavy metal concentrations in sediments occur at the Pearl River. The concentrations of heavy metals in surface sediments from the studied locations are in a descending order: Zn > Cr > Cu > Ni > Pb > Cd. Regarding chemical fractions, Cd showed the highest proportion of acid soluble fraction (F1) among all studied heavy metals. The high mobility of Cd poses a significant threat to water bodies and the surrounding environment. The potential ecological risk index (RI) showed the Pearl River sediments exhibited significantly higher values than the estuary sediments. Cd was found to be the primary contributor to potential ecological risk, accounting for 74% of RI. The health risk assessment showed the total hazard index (HI) for child was exceeded 1 mainly driven by Zn, indicating that the child population was at risk of non-carcinogenic effects. Besides, unacceptable carcinogenic risk in both Pearl River and estuary area were observed for children. The positive matrix factorization (PMF) model was used to ascertain sources of six heavy metals and apportion their contributions in sediments. The results showed that the source contributions of natural, industrial, and mixed sources from coal combustion and traffic emissions accounted for 39.81%, 34.10%, 26.10%.

Properties and environmental quality of the overburden and tailings of manganese mining in the Eastern Amazon

Knowledge about the characteristics of overburden and tailings from manganese (Mn) mining is essential for defining their levels of potentially toxic elements (PTEs) and appropriate environmental management. This study aimed to assess the total and bioavailable contents of PTEs in Mn mining areas in the Eastern Amazon, as well as the associated environmental risks. The samples were collected in areas of overburden and tailings deposition, in addition to forest soils in the Azul mine, Carajás Mineral Province, Brazil. These samples were characterized in terms of fertility, granulometry, and total and bioavailable PTE contents. The pH values of the forest soil were more acidic than those of the overburden and tailings, and the organic matter contents were considerably higher in the forest soil. All PTEs, especially Mn, Ba, Cu, Zn, and Pb, presented higher contents in the overburden and tailings. However, chemical fractionation revealed that PTEs were predominantly in the residual fraction, with percentage contents above 60% of the total content. These results suggest a low risk of environmental contamination. The findings of this study may support more efficient environmental rehabilitation in Mn mining areas in the Amazon.

CFD Modelling and Optimization of Solid Waste Combustion in a 1 MW Fixed Bed Combustion Chamber

The global population and energy consumption grow each year. Therefore, the tendency to use biofuels instead of fossil fuels assist the global requirement. Also, enhancing of the combustion efficiency and minimizing pollutant emissions during the combustion of municipal solid waste (MSW). The present study employed a CFD model to simulate solid fuel combustion in a grate combustion chamber which was commonly used in small-capacity boilers. computational fluid dynamics technique was used to simulate complex solid fuel reactions where 1 MW boiler was supposed for wood and coal combustion. The achievements found that 10%-dried MSW was used as fuel. The results of the study were related to the average gas flow temperatures and composition in the furnace outflow section, as well as the high combustion temperatures of fossil fuels. The results for the average temperature and average chemical molecular fractions (CO, O2, CO2, H2O, and N2) generated at the exit of the combustion process were positive. Thus, it was found that the thermal efficiency of the boiler was significantly affected by the amount of air supplied to the system at a temperature of 273 K and atmospheric pressure. We observed variations in flame morphology, temperature profiles, and corresponding numerical values.

Calculations of the conversion factor from organic carbon to organic matter for aerosol mass balance

Aerosol mass balance studies based on filter samples require a conversion factor to derive organic matter (OM) concentrations from organic carbon (OC) measurements from thermo-optical methods. This factor provides indirect insights on the molecular structure of OM needed in chemical transport models. Site- and season-specific ratios of OC to OM (fOM:OC) were calculated using data from five rural background sites in France between 2012 and 2021 by relating the unidentified chemical fraction in PM2.5 samples to thermo-optical OC concentrations. Further, multiple linear formulations were used to evaluate the impact of possible artefacts on the determination of fOM:OC. The resulting fOM:OC was then compared to other estimates derived from online aerosol mass spectrometry data, showing good agreement. The spatial and temporal variability in fOM:OC is discussed considering factors such as seasonality, meteorological conditions and the atmospheric oxidative potential. Linear-mixed effect models were formulated to quantitatively determine the drivers which influence the fOM:OC at the French rural background sites. Both ozone and relative humidity were variables with statistically significant effects on fOM:OC, indicating that differences in the contributions from both photooxidation and water content, explain the variability in fOM:OC observed at the French rural background sites. Site-specific fOM:OC yielded more accurate PM2.5 mass closure and are therefore recommended in mass-balance exercises. Accurate fOM:OC are critical to maintain consistency in OM time series, especially in cases where filter-based time series may be replaced by state-of-the-art online instrumentation.

Analysis of heavy metals in sediments with different particle sizes and influencing factors in a mining area in Hunan Province

Heavy metals mainly exist on the surface of sediment particles and are transported using particulate matter as carriers. Therefore, the particle size of sediment particles can affect the adsorption, release, and migration of heavy metals. This study aim to investigate the distribution characteristics and chemical fraction of Cd, Pb, and As contents in sediments of different particle sizes using the BCR method, and to determine the key factors affecting the distribution of heavy metals through mineralogical methods such as XRD and EDS. The results revealed that the overall content of various forms of heavy metals increases with the decrease of particle size, mainly presents in fine particles. The mineralogical analysis results indicated that fine particles predominantly contained clay minerals such as chlorite and illite and coarse particles mainly include primary minerals. Due to the mining areas in the middle-upstream, Cd, Pb and As were primarily associated with galena, sphalerite and pyrite, respectively. The distribution of heavy metals is jointly influenced by sediment particle size and sediment material composition.

Comparative study of the sequential extraction methodologies for fractionation analysis of mercury in coal of Thar coalfield.

The primary objective of this study was to evaluate the bound fractions of mercury (Hg), physicochemical parameters, and mineral composition of coal. Coal samples were collected from various depths within Block-VII of the Thar coalfield in Pakistan. The Hg associated with different chemical fractions of coal was extracted using a sequential extraction scheme as per the community bureau of reference (BCR) protocol. This study utilized both the BCR-sequential extraction method (BCR-SEM) and a single-step sequential extraction based on an ultrasonic-assisted method (SSE-UAM) for the fractionation analysis of Hg in coal. The extraction methodologies, BCR-SEM and SSE-UAM, were specifically designed for analyzing Hg fractionation in coal samples. The SSE-UAM offers an operational advantage, requiring only 2h compared to the 51h needed for BCR-SEM. The analyses were validated using standard reference material (SRM-1635a) and the spiking addition method, achieving a recovery percentage of 97.1% for total Hg concentrations using the pseudo-extraction method in SRM-1635A. Total Hg content in the coal samples ranged from 0.60 to 2.34µgg-1 across four different coal seams from Block-VII of the Thar coalfield. Additionally, Hg concentration was observed to decrease with increasing depth, attributed to changes in mineralogical composition. The highest concentration of Hg was detected at a depth of 200-203m, while the lowest concentration was at a depth of 152-154m. The concentration of Hg in various fractions was 32-60% in the acid-soluble fraction, 1.72-4.92% in the reducible fraction, and 9.58-50.8% in the oxidizable fractions. The coal sample characteristics were analyzed using an elemental analyzer and scanning electron microscopy with energy-dispersive spectroscopy. Cold vapor atomic absorption spectrometry (CV-AAS) was used to measure the extracted fractional concentration of Hg in coal.

Pasture Recovery Period Affects Humic Substances and Oxidations of Organic Matter in Eastern Amazon

Land management practices that overlook soil limitations and potential have led to varying degrees of degradation. This study evaluates the carbon content in chemical and oxidisable soil fractions across different pasture recovery periods, comparing them to secondary forests. The management practices assessed include the following: secondary forest (SF), perennial pasture (PP), perennial pasture recovered five years ago (P5), and perennial pasture recovered eight years ago (P8), all on Plinthosols. We analysed carbon levels in oxidisable fractions and humic substances at depths of 0–0.10 m, 0.10–0.20 m, 0.20–0.30 m, and 0.30–0.40 m. The SF and P8 areas showed the highest organic matter content within the humic fractions, compared to the PP and P5 areas. Additionally, the P8 area demonstrated an increase in the labile and moderately recalcitrant fractions of organic matter, standing out among the different fractions evaluated. The multivariate principal component analysis indicated that P8 has the greatest impact on soil quality, followed by FS, P5, and PP. The pasture recovery over the past eight years has significantly improved soil carbon accumulation, highlighting the benefits of land restoration.

Chemical and spectroscopic composition of humic substances in soil subjected to pig manure applications for ten years

ABSTRACT Application of pig manure (PM) in agriculture can influence the amount and composition of soil organic matter (SOM). This study evaluated the changes in contents and stock of C in chemical fractions of SOM and the chemical and spectroscopic composition of humic substances (HS) in a Typic Hapludult (Argissolo Vermelho-Amarelo) after ten years of PM application. Experimental area received 90 and 180 kg ha -1 of N in the form of pig slurry (PS90 and PS180) and pig deep litter (DL90 and DL180), in addition to the control, without application (SA). Soil samples were prepared, and the chemical fractioning of SOM, elemental analysis, and Fourier Transform Infrared Spectroscopy of HS were performed. Applications of PM favored the accumulation of C in soil (up to 53 %), and PS180 increased humic acids (HA) (up to 185 %), while applications of DL favored the increase of hydrophilic substances extracted with HCl and humin (HU) (up to 10 times and 60 %, respectively). Applications of PS180 and DL180 promoted an increase in the aromatic and carboxylic character of the HS, increasing cationic exchange capacity. Therefore, PM applications, especially with DL, contribute positively to C fixation in the soil and the chemical composition of organic material.

Use and recovery of P reserves in Southern Brazil Oxisols under no-till with low and high P availability

ABSTRACT The accessibility of soil P reserves by plants on highly weathered Brazilian soils remains unclear. In this study, we assessed the contribution of soil P fractions to P uptake by soybean plants in two no-till Oxisols (Latossolos), with low and high initial content of available P. The recommended P rates (viz., 153 and 50 kg ha -1 yr -1 in the low-P and high-P soil, respectively) were applied in the form of triple superphosphate (TSP) or Bayovar rock phosphate (BRP) plus a treatment without fertilizer. Yields of winter cereals and soybean on the studied soils were examined over a period of three years. Soil samples were collected in the 0.00-0.10 m soil layer and subjected to sequential chemical fractionation of P. In the last crop season, the P content of soybean shoot biomass was determined. Soil P fractions and P content of soybean shoots were subjected to path analysis. The addition BRP in the low-P soil resulted in a winter cereal yield of 2.0 Mg ha -1 lower than TSP. In the scenario of high P, it is possible to maintain high crop yields even without phosphate fertilization for three consecutive years. Path analyses demonstrated the addition of P using either TSP or BRP boosted the contribution of the more labile inorganic P fractions. The addition of BRP should be avoided in P-deficient soils. The addition TSP or BRP reduces the pressure of plants to use soil P reserves. Therefore, the soil P legacy should be considered in fertilization recommendations for high-P soils in NT.

Transformations of phosphorus and potassium in rice straw biochar based on chemical fractionation

Biochar is an excellent soil amendment, but its fertilizer effect on the soil is often overlooked. In this study, a series of experiments were conducted to investigate the form changes of P (phosphorus) and K (potassium) in rice straw biochar at different pyrolysis temperatures and explore its fertilizer effect characteristics. The results showed that in the rice straw, P was mainly in the form of OP (organophosphorus) and NaOH-P (NaOH extractable phosphorus), and K as WSK (water-soluble potassium). For biochars, the various forms of P at 100–200 °C and K at 100–300 °C were basically unchanged; OP in rice straw biochar decreased gradually from 200 °C to 800 °C; at 200–1000 °C, NaOH-P in biochar gradually decreased, with 9.1 % of P (wt%) at 1000 °C; HCl-P (HCl extractable phosphorus) with more bioavailable, which was mainly converted from NaOH-P and OP, increased gradually from 6.8 % to 50.9 % for P (wt%) at 200–1000 °C. At 100–500 °C, the change of TK (total potassium) was slight; from 500 °C to 900 °C, WSK decreased from 84.7 % to 23.2 % for K (wt%); at 700–1100 °C, the ASK (acid-soluble K) was relatively high, with K (wt%) of 10.6–11.6 %. The volatilization was mainly at 200–500 °C for P and 500–900 °C for K, which volatilization rates were 5.6–30.3 % and 6.3–58.9 %, respectively. Moreover, HCl-P increased from 0.167 mg/g for the raw straw to 4.554 mg/g for the 1000 °C biochar and TK from 3.632 mg/g for the rice straw to 20.91 mg/g for the 600 °C biochar. It can be concluded that the biochars at 400–700 °C were suitable for use as a slow-release P fertilizer and K fertilizer. This work provides a strong basis for using a rice straw biochar at different temperatures as a P and K fertilizer.Capsule: By pyrolysis, the rice straw biochar contains more HCl-P and TK, and can be used as slow-release P fertilizer and K fertilizer.

Electrokinetic-enhanced sulfuric acid leaching of uranium from sandstone uranium ores

Solute transport in conventional acid leaching of sandstone uranium ores is limited by diffusion and convection, resulting in extended leaching cycles. This study described an electrokinetic-enhanced method for leaching sandstone uranium ore with sulfuric acid and was intended to investigate the impacts of potential gradients on leaching efficiency. Electrokinetic horizontal column leaching experiments were conducted on sandstone uranium ore. After 20 h of leaching, the uranium leaching efficiencies were 54.90 %, 56.36 %, 68.33 %, and 82.04 % for potential gradients of 0, 0.5, 1.0, and 2.0 V/cm, respectively. The uranium leaching efficiency of sandstone at a 2.0 V/cm potential gradient was 27.14 % greater than that at a 0 V/cm potential gradient, and the leaching time was decreased by approximately 40 % at the same uranium leaching efficiency. Analyses of the chemical fraction of uranium, XRD and SEM-EDS showed that the applied potential gradient facilitated solute transport during leaching, thus accelerating the leaching efficiency of adsorbed uranium, tetravalent uranium, and uranium encapsulated in lattices of silicates and primary and secondary minerals in sandstone uranium ores. Therefore, electrokinetic action is excellent for enhancing the effectiveness of sulfuric acid leaching of sandstone uranium ores and has broad application prospects.

8-Methoxypsoralen (8-MOP) Isolated from Ficus petiolaris (Moraceae) Has Insecticidal Activity against Spodoptera frugiperda

In this study, we tested the insectistatic and insecticidal effects of the ethanolic extract of stems and bark of Ficus petiolaris Kunth (Moraceae) in laboratory bioassays with an artificial diet against newly hatched larvae of the fall armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae). The extract was evaluated at five different concentrations (500, 1000, 1500, 2000, and 2500 ppm). The 2500 ppm extract had the strongest inhibitory effects on larval (89%) and pupal (20%) weight as well as the highest mortality (80%). The positive control, methyl parathion (Methyl Parathion®) at 1%, eliminated 100% of the fall armyworm, and the negative control (artificial diet) had a mortality of only 5%. Chemical fractionation of F. petiolaris stem and bark extract produced five fractions of FpR1-5, each of which was evaluated at 250, 500, 750, 1000, and 1250 ppm. FpR4 presented the strongest inhibitory effect, reducing the weight of the larva and pupa by 35% and 18%, while FpR2 had the strongest insecticidal effect, with 90% mortality at 1250 ppm. The pure 8-Methoxypsoralen compound extracted from this fraction was even more effective, with 100% S. frugiperda mortality at 100 ppm. The 50% lethal concentration (LC50) of 8-Methoxypsoralen was 67.68 ppm. Our results indicate that the F. petiolaris extract showed toxic activity against the fall armyworm, and its compound 8-Methoxypsoralen showed strong insecticidal activity at low concentrations.

Contrasting metal bioaccumulation in marine benthic invertebrate groups in polluted harbor sediments

This study examined the sediment metal fractions and availability to infer bioaccumulation in marine harbor benthic organisms. Total metals were analyzed using atomic absorption spectrometry and inductively coupled plasma-optical emission spectrometry for chemical fractions and organisms. The results showed similar metal concentrations and distribution driven by rivers and harbor pollution. We found significant differences in metal accumulation in marine benthic groups, highest in scavenger species. Their metal concentrations in decreasing order were 1.97–4568, 0.10–1260, 1.64–159, and 0.105–112 μg g−1 dw for hermit crabs, forams, bivalves, and polychaetes. Moreover, certain organisms, such as tusk shells, sea pens, bivalves, forams, and isopods, may exhibit selective metal accumulation. Biota-sediment accumulation factors (>1) were highest for essential metals like Cu, Zn, and Mn, while toxic metals like As, Cr, Co, and Ni increased. This concurrent assessment provides more comprehensive data for metal bioaccumulation in marine benthic ecosystems.