The adsorption of ethyl acetate, a volatile organic compound, on activated carbons, synthesized from various precursors based on by-products and waste materials—polymer, biomass, coal tar pitch—was studied. The activated carbons were prepared by thermochemical treatment of the precursors, carbonization, and subsequent activation with water vapor. Surface and textural properties of obtained carbon adsorbents were characterized by low-temperature N₂ adsorption, Boehm’s method, etc. The activated carbons are distinguished by relatively high surface area and developed pore structure. The adsorption investigations were performed with water solutions of ethyl acetate, and the obtained results fit well the Langmuir model, as well as the Freundlich model. All activated carbons demonstrated considerably high adsorption capacity in the range 160–450 mg/g. The obtained data indicate that the adsorption ability of activated carbon toward ethyl acetate depends on the surface area, and it increases with increasing the content of mesopores, where ethyl acetate molecules are preferably adsorbed.

Silicon (Si) is one of beneficial elements for rice and is considered to enhance plant resistance to toxic metals. Nanofertilizers generally have a smaller particle size and specific characters and behaviors in soil and plants. Thus, nano-Si fertilizers may putatively have an advantage over traditional fertilizers in reducing heavy metal accumulation in rice straws and grains, but their effects still require investigation. Here, using a greenhouse pot culture experiment, we studied the effects of foliar application with organic or inorganic nano-Si on growth and yields, and heavy metal accumulation in six rice cultivars grown in soil artificially polluted with Cd, Pb, Cu, and Zn. Generally, hybrid cultivars had higher biomass and yields than conventional cultivars (P < 0.001), and nano-Si showed positive effects on at least four cultivars (P < 0.001). The average spike weight of six cultivars increased to 25.3 and 24.8 %, respectively, by inorganic and organic nano-Si. Hybrid cultivars generally had higher Cd concentrations in roots, shoots, and grains than conventional cultivars. In most cases, both organic and inorganic nano-Si reduced concentrations (P < 0.01) and bio-concentration factor (BCF) of the heavy metals in grains and decreased the translocation factor (TF) of heavy metals from roots to shoots and/or from shoots to grains, and the most pronounced effects were found on Cd. The average grain Cd concentration decreased to 27.1 and 23.8 %, respectively, by inorganic and organic nano-Si. In general, inorganic nano-Si had more pronounced effect than organic nano-Si on both rice growth and heavy metal accumulation. This present study firstly showed that nano-Si had positive effects on the growth and yields of rice grown in multi-metal-polluted soil and potentially reduced heavy metal accumulation in rice, especially the toxic Cd in grains. However, both rice cultivar and chemical form of Si fertilizers should be taken into account to develop efficient nano-Si fertilizers for preventing heavy metal-contaminated rice grains.

An estimated 4.9 million barrels of crude oil and natural gases was released into the Gulf of Mexico during the Deepwater Horizon oil spill of 2010. The Deepwater Horizon oil spill affected the aquatic species in the Gulf of Mexico, vegetation, and the human population along the coast. To reduce the effect of the spilled oil on the environment, different remediation strategies such as chemical dispersant, and mechanical booms and skimmers were utilized. Over 2.1 million gallons of dispersants was applied to minimize the impact of the spilled oil. However, environmental and human toxicity issues arose due to the perceived toxicity of the dispersant formulations applied. After the Deepwater Horizon oil spill, various studies have been conducted to find alternative and environmentally benign oil spill response strategies. The focus of this manuscript is to demonstrate an objective and an overall picture of current research work on oil spill response methods with emphasis on dispersant and oil sorbent applications. Current trends in oil spill sorbent and dispersant formulation research are presented. Furthermore, strategies to formulate environmentally benign dispersants, as well as the possible use of photoremediation, are highlighted.

The important effects of minerogenic particles delivered from watersheds on optical and phosphorus metrics of lacustrine water quality have recently been quantified through measurements of the projected area of these particles per unit volume of water (PAVₘ), using an individual particle analysis technique. A mass balance type model for PAVₘ, partitioned according to the contributions of four size classes, is developed and tested for Cayuga Lake, New York, supported by long-term monitoring of PAVₘ in the lake and its primary tributaries. The model represents the source of PAVₘ of tributary inputs and three in-lake loss processes: (1) size-dependent settling, (2) enhancement of settling through aggregation, and (3) filter feeding by dreissenid mussels. The central roles of major runoff events and localized external loads of minerogenic sediment at one end of the lake in driving patterns of PAVₘ in time and space are successfully simulated, including (1) the higher PAVₘ levels in a shallow area (“shelf”) adjoining these inputs, relative to pelagic waters, following runoff events; and (2) the positive dependence of the shelf increases on the magnitude of the event. Analyses conducted with the model establish that settling, with aggregation enhancement, dominates the loss of PAVₘ from the water column of the shelf, while mussel filtration increases in relative importance in pelagic waters. The utility of PAVₘ predictions to quantify the effects of these particles on optical and phosphorus concentration metrics of water quality is established.

This paper has its origin via an inadvertent error wherein a length of rubber hose was added to the sampling line of a sulphur gas analyser at the Australian Baseline Station at Cape Grim. This carbon disulphide (CS₂) contamination source was removed after a period of 10 weeks. In the interim, substantial data was collected and is here compared with the record of ambient station temperatures. CS₂ was found to vary with ambient temperature over both short and monthly time scales. Comparisons of linear, natural log (ln) and log₁₀ correlations yield the conclusion that log₁₀ and ln CS₂ emission vs. temperature (°C) associations provide the best correlations. No significant depletion of CS₂ emission from the rubber over a 10-week period was detected. Implications for regional and global emission inventories of CS₂ and carbonylsulphide (COS) are discussed.

This study aimed to assess the micronuclei formation in Tradescantia pallida var. purpurea through active and passive biomonitoring of air genotoxicity and its relation with abiotic environmental factors, and to analyze the concentrations of trace elements in flower buds and leaves, in order to determine the importance of these parameters to atmospheric quality monitoring. For 2 years, active biomonitoring was conducted with exposure of cuttings with flower buds at three sites in the metropolitan area of Porto Alegre in southern Brazil, and indoor (negative control). For passive biomonitoring, flower buds were collected from beds at the same sites. Meteorological and vehicular traffic data were recorded during the exposures. The micronuclei (MCN) frequencies obtained by active and passive biomonitoring for Canoas, Esteio, and São Leopoldo (respectively means of 5.44, 5.34, 4.17 and of 3.01, 2.47, 2.72) were significantly higher than those of the negative control. Furthermore, the sensitivity of the flower buds used for active biomonitoring was greater compared to those used for the passive biomonitoring, which was evidenced by significantly higher MCN frequencies. The multivariate analysis indicated two main components responsible for 74.58 % of the variances observed, and pointed to a strong relation between micronuclei frequency from active biomonitoring and vehicular traffic. Temperature and relative air humidity did not relate with the formation of micronuclei in both biomonitoring systems. Flower buds proved to be efficient bioaccumulators of trace elements, as they accumulated concentrations of up to three times more than the leaves.

This work investigates the sorption behaviour of six hydrophobic organic compounds (HOCs) from the trichlorobenzenes (TCBs) and polycyclic aromatic hydrocarbons (PAHs) on Danube sediment using batch and column experiments, either in the presence or absence of carbon nanotubes (CNTs). For all HOCs investigated, nonlinear isotherms were obtained. Based on logKoc, it can be concluded that the Danube sediment has a higher sorption affinity for PAHs than TCBs. A positive correlation between HOC molecular hydrophobicity and sorption affinity was obtained, meaning that hydrophobic interactions play a significant role. There was a negative correlation between molecular hydrophobicity and the percentage of eluted HOCs, indicating that more hydrophobic molecules show less mobility in the sediment column. In the presence of CNTs in the sediment column, HOC concentrations in the column eluate decreased by factors of 2–3. Metal oxides and hydroxides on the surface of the sediment under the given experimental conditions had positively charged centres that caused the deposition of CNTs, leading to simultaneous sorption of organic compounds on both sediment organic matter (SOM) and CNTs. The increased retention of HOCs in the presence of CNTs on the sediment column reduces their mobility, which might also suggest that CNTs may be used for remediation of contaminated soils and sediments.

Elevated plant-available cadmium (Cd) in soils results in contamination to cacao (Theobroma cacao L) beans. Effectiveness of vermicompost and zeolite in reducing available Cd in three cacao-growing soils was studied under laboratory conditions. Sorption–desorption experiments were conducted in soils and amendments. Cadmium was added at 0 or 5 mg kg⁻¹ (spiked), then, amendments were incorporated at 0, 0.5, or 2 %. Amended soils were incubated at room temperature for 28 days. Plant-available Cd was determined using 0.01 M CaCl₂ (WSE) and Mehlich 3 (M3) extraction procedures in subsamples taken from individual bags at six time intervals. Soils and amendments displayed different sorption characteristics and a better fit was attained with Freundlich model (R ² > 0.82). Amendments were ineffective in reducing extractable Cd in non-spiked soils. In Cd-spiked soils, vermicompost at 2 % significantly reduced WSE-Cd (P < 0.01) from 3.36, 0.54, and 0.38 mg kg⁻¹ to values lower that instrument’s detection in all the three soils and significantly diminished M3-extractable Cd (P < 0.05) from 4.62 to 4.11 mg kg⁻¹ in only one soil. Vermicompost at 0.5 % significantly decreased WSE-Cd (P < 0.01) from 3.04 and 0.31 to 1.69 and 0.20 mg kg⁻¹, respectively, in two soils with low sorption capacity for Cd. In contrast, zeolite failed to reduce WSE- or M3-extractable Cd in all studied soils. A negative correlation occurred between soil pH and WSE-Cd (r > −0.89, P < 0.01). The decrease in WSE-Cd appears to be associated with the increase in pH of the vermicompost-amended soils.

Pathogenic human viruses cause over half of gastroenteritis cases associated with recreational water use worldwide. They are difficult to concentrate from environmental waters due to low numbers and small sizes. Rapid enumeration of viruses by quantitative polymerase chain reaction (qPCR) has the potential to improve water quality analysis and risk assessment. However, capturing and recovering these viruses from environmental water remain formidable barriers to routine use. Here, we compared the recovery efficiencies of human adenoviruses (HAdVs) and human polyomaviruses (HPyVs) from 10-L river water samples seeded with raw human wastewater (100 and 10 mL) using hollow-fiber ultrafiltration (HFUF) and glass wool filter (GWF) methods. The mean recovery efficiencies of HAdVs in river water samples through HFUF were 36 and 86 % for 100 and 10 mL of seeded human wastewater, respectively. In contrast, the estimated mean recovery efficiencies of HAdVs in river water samples through GWF were 1.3 and 3 % for 100 and 10 mL seeded raw human wastewater, respectively. Similar trends were also observed for HPyVs. Recovery efficiencies of HFUF method were significantly higher (P < 0.05) than GWF for both HAdVs and HPyVs. Our results clearly suggest that HFUF would be a preferred method for concentrating HAdVs and HPyVs from river water followed by subsequent detection and quantification with PCR/qPCR assays.

The implantation of wastewater treatment systems aims to minimize environmental impacts, but ultimately generates waste materials, such as sewage sludge, which must be properly discarded. Final disposal in landfills, and incineration are the most commonly used disposal methods, but both constitute a threat to the soil, water, air, and food chain. The most suitable alternative for the disposal of sewage sludge is its use as fertilizer, due to the nutrients in its composition, such as nitrogen, phosphorus, and organic carbon. However, the presence of potentially toxic metals is the main factor that limits such use. Many techniques have been employed in attempt to remove these toxic metals, including physical, chemical, and biological treatments, but the high cost of the physical and chemical treatments, as well as the risk of causing secondary pollution, makes this type of sewage sludge treatment an unsatisfactory option. Therefore, removing toxic metals through biological treatments has become an increasingly popular choice, as such treatments have been shown to be the most economically and environmentally beneficial methods. The aim of the present study was to provide a review of some of the most common alternative treatments for the incineration and disposal of sludge in landfills, emphasizing the physical, chemical, and biological processes that enable the removal of potentially toxic metals, for the purpose of obtaining a final product which can be used as fertilizers in farm soils.