Interaction between silver nanoparticles (AgNPs) and iron plaque, which forms at the root surface of wetland plants under waterlogging conditions, is a critical process that controls the bioavailability of AgNPs. In this study, we comparatively evaluated how and to what extent iron plaque affected silver uptake sourced from metallic (Ag⁰NPs) and sulfidized (Ag₂S-NPs) silver nanoparticles under hydroponic conditions. After the formation of iron plaque at the root surface upon exposure to Fe²⁺ at 0–100 μg mL⁻¹, rice (Oryza sativa L.) seedlings were transferred to AgNP suspensions. Silver uptake depended on the amount of iron plaque and AgNP species (Ag⁰NPs vs. Ag₂S-NPs): Ag₂S-NP exposure had lower or comparable Ag uptake to that of Ag⁰NP exposure at low levels of Fe²⁺ (0–80 μg mL⁻¹), but significantly higher Ag uptake at 100 μg Fe²⁺ mL⁻¹. Such contrasting effects of iron plaque on the bioavailability of Ag⁰NPs and Ag₂S-NPs were attributed to their influences on AgNP dissolution. However, the translocation factors (TFs) and particle size distribution of NPs in planta (as determined by single-particle inductively coupled plasma-mass spectrometry analysis) were not affected by the amount of iron plaque. These results reveal contrasting effects of iron plaque on the bioavailability of Ag⁰NPs and Ag₂S-NPs, and raise concerns about the exposure of wetland plants to Ag₂S-NPs in Fe-rich environments, where high Fe levels may facilitate Ag₂S-NP bioavailability.

In China, more than 10,000 tons of bean-worm, which is rich in protein (68.5%) and essential amino acids (52.8%), is consumed annually. Thus, a large amount of bean-worm skin waste is generated, and is often indiscriminately disposed of, potentially causing environment problems. In this study, bean-worm skin (BWS) waste was pyrolyzed at 500 °C to produce biochar (BWS-BC), and the surface properties of BWS and BWS-BC were characterized using various spectroscopic techniques. Pb(II) adsorption properties of BWS and the corresponding biochar as a function of solution pH, contact time, and equilibrium concentration of Pb(II) were examined using adsorption isotherm, kinetics and thermodynamics studies. The maximum Pb(II) adsorption capacities based on the Langmuir isotherm model were calculated as 45 and 62 mg g⁻¹ for BWS and BWS-BC, respectively, which were comparable to the values obtained for biochars derived from other agro-wastes. The adsorption feasibility, favorability and spontaneity of Pb(II), as derived from the thermodynamic parameters, indicated that chemisorption and precipitation (e.g., hydroxypyromorphite) were the main adsorption mechanism in case of BWS and BWS-BC, respectively. Thus, conversion of BWS to biochar for Pb(II) adsorption can be considered as a feasible, promising and high value-added approach for BWS recycling.

With the constant quest for new sources of superfoods to supplement the largely nutrient deficient diet of the modern society, sea cucumbers are gaining increasing popularity. Three species of sea cucumbers, Cucumaria frondosa, Apostichopus californicus and Apostichopusjaponicus were collected from three geographical regions, Atlantic and Pacific coast of Canada and Yellow sea/ East China sea in China, respectively. These organisms were sectioned into parts (body wall, tentacles, internal organ, skin and muscle) and analysed for total arsenic (As) by inductively coupled plasma mass spectrometry (ICP-MS) and As species by high-performance liquid chromatography (HPLC) coupled to ICP-MS. Normal and reversed sequential extractions were optimised to address As distribution between lipids (polar and non-polar) and water-extractable fractions. Two extraction methods for water-extractable As were compared in terms of the number and the amount of extracted species. The results revealed that total As concentration and As species distribution varies significantly between sea cucumbers species. Total As in studied body parts ranged between 2.8 ± 0.52 and 7.9 ± 1.2 mg kg⁻¹, with an exception of the muscle tissue of A. californicus, where it reached to 36 ± 3.5 mg kg⁻¹. Arsenobetaine (AsB) was the most abundant As species in A. californicus and A.japonicus, however, inorganic As represented over 70% of total recovered As in the body parts of C. frondosa. Arsenosugars-328 and 482 were found in all studied body parts whereas arsenosugar-408 was only found in the skin of A. californicus. This is the first time that such a variation in As species distribution between sea cucumber species has been shown.

The transport and retention of sediments in fine grain sizes plays an important role in the cycles of phosphorus (P), and is closely related to the extent and potential for eutrophication in water reservoirs. In order to highlight the environmental indications for the transport of fine sediment particles and the associated bioavailable phosphorus (Bio-P) in the world largest reservoir, the Three Gorges Reservoir (TGR), the suspended and bed sediments were collected at 13 sections in 2016. The sediment physicochemical properties, micromorphology of sediment particles, distribution of elements on particle surface, P adsorption parameters, and P fractions in different grain sized sediments were analyzed. The results showed that the fine sediment particles had a strong P adsorption ability due to their micromorphology, mineral compositions, and the high contents of Fe/Al/Mn (hydr)oxides, which contributed a higher concentration of Bio-P in <16 μm sediment particles. The adsorption of P on the sediment particles occurred longitudinally along the TGR, and the fine sediment particles (<16 μm) dominated the transport and distribution of Bio-P in the TGR sediments. The reduced inflow and retention of fine sediment particles, caused by the construction of cascade reservoirs along the Jinsha River (upper reach of the Yangtze River), has resulted in the decrease in the retention of Bio-P in the TGR. Therefore, we conclude that the continuously decrease of inflow and retention of the fine sediment particles in the TGR, and with it a reduced sediment P buffer capacity, may enhance algal blooms occurrence also in view of the increased P discharge from the overall TGR catchment. The study results can contribute to improved management guidance on fine sediment particles and associated phosphorus for the operation and environmental protection of other large reservoirs in the world.

Human factors/errors (such as inappropriate actions by operators and unsafe supervision by organizations) are a primary cause of oil spill incidents. To investigate the influences of active operational failures and unsafe latent factors in offshore oil spill accidents, an integrated human factor analysis and decision support process has been developed. The system is comprised of a Human Factors Analysis and Classification System (HFACS) framework to qualitatively evaluate the influence of various factors and errors associated with the multiple operational stages considered for oil spill preparedness and response (e.g., oil spill occurrence, spill monitoring, decision making/contingency planning, and spill response); coupled with quantitative data analysis by Fuzzy Set Theory and the Technique for Order Preference by Similarity to Ideal Solution (Fuzzy-TOPSIS) to enhance decision making during response operations. The efficiency of the integrated human factor analysis and decision support system is tested with data from a case study to generate a comprehensive priority rank, a robust sensitivity analysis, and other theoretical/practical insights. The proposed approach improves our knowledge on the significance of human factors/errors on oil spill accidents and response operations; and provides an improved support tool for decision making.

Veterinary antibiotics have been detected as contaminants of emerging concern in soil environment worldwide. Animal manure is frequently applied to agricultural fields to improve soil fertility, which can result in introducing large amount of antibiotics into soil environment. However, few attempts have been made to identify the spatial and temporal dynamics of veterinary antibiotics in soil at the hillslope scale with different land uses. This study was performed to explore the pattern and variability of veterinary antibiotics in the soil in response to rainfall events. Results showed that higher concentrations of veterinary antibiotics were generally found in cropland (292.6 ± 280.1 ng/g) and orchard (228.1 ± 230.5 ng/g) than in forestland (13.5 ± 9.9 ng/g). After rainfall events, antibiotics accumulated in the soil at the positions where manure was applied, especially under high-intensity rainfall conditions. However, the antibiotic concentration in soil slightly increased from the top to the bottom of hills, thus indicating the restricted contribution of runoff to antibiotic transport, especially under low-intensity rainfall conditions. In addition, most antibiotics were sequestered in the surface soil (0–10 cm), and higher antibiotic concentrations were observed in deep soil (20–40 cm) in cropland than orchard. The soil aggregate, organic matter, and clay content played important roles in antibiotic sequestration along the hillslope subject to low-, medium-, and large-amount rainfall events, respectively. This study identified that land use, rainfall conditions, and soil structures jointly affect the spatial and temporal variability of antibiotics in soils on hillslopes.

For decades, a vast array of innovative biosorbents have been found out and used in the removal of heavy metals, including bacteria, algae and fungi, etc. Although extensive biological species have been tried as a biosorbent for heavy metals removal, for removal efficiency or economy efficiency limited, it has failed to make a substantial breakthrough in practical application. Thus, many improved methods based on biosorbents emerged. In this review, based on the literature and our research results, we highlight three types of novel methods for biosorbents removal of heavy metals: chemical modification of biosorbents; biomass and chemical materials combination; multiple biomass complex systems. We mainly focus on their configuration, biosorption performance, their creation method, regeneration/reuse, their application and development in the future. Through the comparative analysis of various methods, we think that intracellular autogenous nanomaterials may open up another window in biosorption of heavy metals area. At the same time, the combination of various treatment methods will be the development tendency of heavy metal pollution treatment in the future.

As a result of metal mining activities in Pakistan, toxic heavy metals (HMs) such as chromium (Cr) and lead (Pb) often enter the soil ecosystem, accumulate in food crops and cause serious human health and environmental issues. Therefore, this study examined the efficacy of biochar for contaminated soil remediation. Poplar wood biochar (PWB) and sugarcane bagasse biochar (SCBB) were amended to mine-contaminated agricultural soil at 3% and 7% (wt/wt) application rates. Lactuca sativa (Lettuce) was cultivated in these soils in a greenhouse, and uptake of HMs (Cr and Pb) as well as biomass produced were measured. Subsequently, health risks were estimated from uptake data. When amended at 7%, both biochars significantly (P<0.01) reduced plant uptake of Cr and Pb in amended soil with significant (P<0.01) increase in biomass of lettuce as compared to the control. Risk assessment results showed that both biochars decreased the daily intake of metals (DIM) and associated health risk due to consumption of lettuce as compared to the control. The Pb human health risk index (HRI) for adults and children significantly (P<0.01) decreased with sugarcane bagasse biochar applied at 7% rate relative to other treatments (including the control). Relative to controls, the SCBB and PWB reduced Cr and Pb uptake in lettuce by 69%, 73.7%, respectively, and Pb by 57% and 47.4%, respectively. For both amendments, HRI values for Cr were within safe limits for adults and children. HRI values for Pb were not within safe limits except for the sugarcane bagasse biochar applied at 7%. Results of the study indicated that application of SCBB at 7% rate to mine impacted agricultural soil effectively increased plant biomass and reduced bioaccumulation, DIM and associated HRI of Cr and Pb as compared to other treatments and the control.

During a fire event, potentially hazardous chemicals are formed from the combustion of burning materials and are released to the surrounding environment, both via gas and soot particles. The aim of this investigation was to study if firefighting techniques influence the emission of chemicals in gas phase and soot particles. Five full-scale fire tests were extinguished using four different firefighting techniques. A nontarget chemical analysis approach showed that important contaminants in gas and soot separating the different tests were brominated flame retardants (BFRs), organophosphate flame retardants (OPFR), polycyclic aromatic hydrocarbons (PAHs) and linear hydrocarbons. Reproducibility was evaluated by a field replicate test and it was determined that the temperature curve during the event had a bigger impact on the released chemicals than the firefighting technique used. However, despite fire intensity being a confounding factor, multivariate statistics concluded that water mist with additive resulted in less BFR emissions compared to foam extinguishing. The analysis also showed that the conventional spray nozzle method released more PAHs compared with the water mist method. The comprehensive chemical analysis of gas and soot released during fire events was able to show that different firefighting techniques influenced the release of chemicals.

Global urbanization and plastic pollution has increased the availability and variety of substrates for sessile organisms, and are intensively used by invasive species for settlement. Despite extensive literature describing the strong association between artificial structures and invasive species, little effort has been directed towards identifying the larval traits that favor this selection. Larval selection and settlement are crucial as larvae actively search and interpret environmental cues to identify suitable habitats to settle. The aim of this research was to investigate if invertebrate larvae have a preference for a particular anthropogenic substrate, and how pre-settlement behaviors vary when encountering different substrates. We used two invasive bryozoan species, Bugula flabellata and Bugula neritina, which are commonly found in urbanized areas around the world. Energy expenditure during planktonic and benthonic stages, pre-settlement swimming/exploring behaviors, settlement and larval selectivity were quantified under laboratory conditions on different substrates (concrete, wood, polystyrene, polyvinyl chloride, polyethylene terephthalate and polycarbonate). The energy expenditure measured was higher in planktonic larvae than in early settled larvae. Larvae of both species swam less and explored more when exposed to plastic surfaces, suggesting a preference for this substrate and resulting in lower energy expenditures associated with searching for habitat. Larvae actively chose to settle on plastics rather than on wood or concrete substrates. The results suggest that for Bugula larvae, the likelihood of colonizing plastic surfaces is higher than other materials commonly found in urbanized coastal areas. The more quickly they adhere to artificial substrates the lower the energy expenditure, contributing to higher fitness in these individuals. The strong preference of invertebrate larvae for plastics can potentially extend the distribution range of many invasive marine species as they are able to travel long distances attached to floating debris. This phenomenon will likely exacerbate the introduction of exotic species into novel habitats.