In this study, the impact of hydration status on dermal uptake of pesticides in two species of amphibians is examined. Absorption of pesticides in anurans occurs primarily through a highly vascularized dermal seat patch; however, pesticides can also enter through the superficial dermis following exposure. Despite the growing body of literature on dermal exposure in amphibians, little is known on how hydration status influences uptake. Thus, the objective of this study was to investigate the influence of hydration status on absorption of pesticides (atrazine, triadimefon, metolachlor, chlorothalonil, and imidacloprid) in southern leopard frogs (Lithobates sphenocephala) and Fowler’s toads (Anaxyrus fowleri). Amphibian treatments included dehydration periods of 0, 2, 4, 6, 8, or 10 h prior to exposure to pesticide-contaminated soils for 8 h. Following exposure, soil and whole-body homogenates were extracted and analyzed by LC-MS/MS. Dehydration time was then regressed against post-exposure concentrations to infer the impact of dehydration on dermal pesticide uptake. Increased dehydration time resulted in significantly lowered pesticide concentrations in both species (F₆, ₂₉₃ = 67.66, p = 0.007) for the five pesticides studied. This phenomenon could be due to an energy and/or dilution effect.

To control non-point source (NPS) pollution, it is important to estimate NPS pollution exports and identify sources of pollution. Precipitation and terrain have large impacts on the export and transport of NPS pollutants. We established an improved export coefficient model (IECM) to estimate the amount of agricultural and rural NPS total phosphorus (TP) exported from the Luanhe River Basin (LRB) in northern China. The TP concentrations of rivers from 35 selected catchments in the LRB were used to test the model’s explanation capacity and accuracy. The simulation results showed that, in 2013, the average TP export was 57.20 t at the catchment scale. The mean TP export intensity in the LRB was 289.40 kg/km², which was much higher than those of other basins in China. In the LRB topographic regions, the TP export intensity was the highest in the south Yanshan Mountains and was followed by the plain area, the north Yanshan Mountains, and the Bashang Plateau. Among the three pollution categories, the contribution ratios to TP export were, from high to low, the rural population (59.44%), livestock husbandry (22.24%), and land-use types (18.32%). Among all ten pollution sources, the contribution ratios from the rural population (59.44%), pigs (14.40%), and arable land (10.52%) ranked as the top three sources. This study provides information that decision makers and planners can use to develop sustainable measures for the prevention and control of NPS pollution in semi-arid regions.

Walnut is one of the most popular nuts worldwide and contains various mineral nutrients. Little is known, however, about the relationship between toxic heavy metals in walnuts and growth soil. In this study, we investigated the distribution, relationship, and risk assessment of five toxic heavy metals—lead (Pb), arsenic (As), chromium (Cr), cadmium (Cd), and mercury (Hg)—in walnuts and growth soil in the main production areas of China. The results showed that the main heavy metal pollution in walnut and soil was Pb and Cd. Regionally, positive relationships existed between heavy metals and the pH and organic matter of soil. In addition, we observed a notable uptake effect between walnut and growth soil. In this study, we found a significant correlation (r = 0.786, P < 0.05) between the bioconcentration factors and the longitude of the sampling areas. The risks (total hazard quotients) of five heavy metals toward children and adults by dietary walnut consumption were 46.8 and 56.2%, respectively. The ability to identify toxic heavy metal pollution in walnuts and growth soil could be helpful to screen suitable planting sites to prevent and control heavy metal pollution and improve the quality and safety of walnut.

Engineered nano-TiO₂ (Enano-TiO₂) have inevitably discharged into aquatic sediments that resulted from their widespread use. The physicochemical characteristics of sediments might be changed because of remarkable properties of Enano-TiO₂ and affected by the aging of sediments, thereby altering the environmental behavior and bioavailability of other pollutants such as perfluorooctane sulfonate (PFOS) in sediments. Here, adsorption behavior and mechanism of PFOS on aging aquatic sediments spiked with Enano-TiO₂ at a weight ratio of 5.0% were investigated. The results showed that Enano-TiO₂ significantly altered zero points of charge (pHzₚc) and pore surface properties of sediments, manifested as pHzₚc, the total surface area (SBET), the micro-pore surface area (Sₘᵢcᵣₒ), and the external surface area (Sₑₓₜ) of sediment particles contaminated with Enano-TiO₂ clearly increased, instead average pore size decreased. Rapid intra-particle diffusion processes were well fitted by the pseudo-second-order rate model with the sorption rate (K₂) following the order single (5.764 mg/(g·h)) > binary systems (3.393 mg/(g·h)). Freundlich model best described the sorption isotherm data with the larger sorption capacity (KF) and sorption affinity (1/n) of sediments spiked with Enano-TiO₂ than that of sediments only. Additionally, Enano-TiO₂ changed the adsorption thermodynamics of PFOS on the sediments with the absolute value of ∆G⁰, ∆H⁰, and ∆S⁰ increased. Fourier transform infrared (FT-IR) spectroscopy suggested possible formation of a negative charge-assisted H-bond between PFOS and the functionalities on sediment surfaces, including O–H of carboxyl, alcohol, phenols, and chemisorbed H₂O as well as carbonyl groups (C=O) of ketone groups. Furthermore, the multilayer sorption of PFOS on sediments contaminated with Enano-TiO₂ is plausible because of bridging effect of Cu²⁺ and Pb²⁺.

Investigation of presence of Uranium (U) in groundwater/drinking water is an active are of research due to its chemical and radiological toxicity as well as long-term health effects. The current study had the objective of estimating U as a naturally occurring radioactive element in groundwater samples and assessment of ingestion dose, when groundwater is the source of drinking water. The random sampling method was chosen for the collection of samples based on population density. The estimation of U was done using LED fluorimeter. Statistical tools were applied to analyze the data and its spatial distribution. The U concentrations in three blocks of urban Patna were well below the permissible limits suggested by different health agencies of the world. A correlation test was performed to analyze the association of U with other physiochemical parameters of water samples. It was found that the sulfate, chloride, calcium, hardness, alkalinity, TDS, salinity, and ORP were positively correlated, whereas fluoride, phosphate, magnesium, dissolved oxygen, and pH were negatively correlated with U concentrations. The ingestion dose due to U, occurring in groundwater, was found to vary from 0.2–27.0 μSv y⁻¹ with a mean of 4.2 μSv y⁻¹, which was well below the recommended limit of 0.1 mSv (WHO WHO Chron 38:104–108, 2012).Therefore, the water in this region is fit for drinking purposes.

The effect of EDTA and citric acid on accumulation, toxicity of heavy metals (Cu, Zn, Cd, and Pb), and growth of Moso bamboo was investigated in current experiment. The availability of heavy metals in soil and its uptake by plants has indicated toxicity. The results revealed that EDTA and citric acid has reduced biomass of Moso bamboo but non-significant difference in biomass was observed compared with control. Application of EDTA (10 mmol kg⁻¹) has significantly improved copper (Cu) by 56.5 and 84.9% in roots and above ground parts of plants. Application of EDTA (10 mmol kg⁻¹) has significantly enhanced lead (Pb) by 51.8 and 210.8% in roots and above ground parts of Moso bamboo. Furthermore, treatment of EDTA has significantly improved activities of water-soluble Cd, Cu, and Pb in soil by 98.9, 70.1, and 73.1 times compared with control. In case of contents of diethylenetriaminepentaacetic acid (DTPA)-extractable metals, the treatment of EDTA (10 mmol kg⁻¹) has produced maximum increase of 244.5 mg kg⁻¹ Zn and 157.9 mg kg⁻¹ Pb, respectively. It is concluded that effect of EDTA was superior compared with citric acid for improvement of phytoremediation potential of Moso bamboo.

Composting leachates were collected to investigate the fluorescent characteristic and compositional change of dissolved organic matter (DOM) and the effects of the DOM and nutrients on heavy metal distribution during a leachate combination treatment process. Excitation-emission matrix (EEM) fluorescence spectra showed that, with the progress of the treatment units, the content of fulvic-like, humic-like, and protein-like substances gradually decreased. One fulvic-like component (C1), three humic-like components (C2, C3, and C4), and three protein-like components (C5, C6, and C7) were identified in the leachate DOM by parallel factor analysis. Anaerobic-aerobic processes removed a large fraction of the tyrosine-like component (C7) and tryptophan-like component (C6) and a small amount of humic-like component (C2), while the membrane bioreactor showed a good removal effect on protein-like component. The ultra-filtration membrane treatment had a removal effect on fulvic-like and humic-like component and other recalcitrant compounds, while the reverse osmosis treatment had a good removal effect on both humic-like and protein-like components. Correlation analysis indicated that Mn and Cr were primarily associated with protein-like components and nutrients in the composting leachates. Ni and Pb were bound to fulvic-like, humic-like, and protein-like components, Co and Zn interacted with inorganic nitrogen and total phosphorus, and Cd only interacted with inorganic nitrogen.

In the present study, surface ozone (O₃), nitrogen oxides (NOₓ), and carbon monoxide (CO) levels were measured at two sites downwind of fire active region in the Indo-Gangetic Plain (IGP): Agra (27.16° N, 78.08° E) and Delhi (28.37° N, 77.12° E) to study the impact of post-harvest crop-residue fires. The study period was classified into two groups: Pre-harvest period and Post-harvest period. During the post-harvest period, an enhancement of 17.3 and 31.7 ppb in hourly averaged O₃ mixing ratios was observed at Agra and Delhi, respectively, under similar meteorological conditions. The rate of change of O₃ was also higher in the post-harvest period by 56.2% in Agra and 39.5% in Delhi. Relatively higher O₃ episodic days were observed in the post-harvest period. Fire hotspots detected by Moderate Resolution Imaging Spectroradiometer (MODIS) along with backward air-mass trajectory analysis suggested that the enhanced O₃ and CO levels at the study sites during the post-harvest period could be attributed to crop-residue burning over the North-West IGP (NW-IGP). Satellite observations of surface CO mixing ratios and tropospheric formaldehyde (HCHO) column also showed higher levels during the post-harvest period. Graphical abstract

The development of environmentally sustainable control strategies to fight insect pests is a key challenge nowadays. Pheromone-mediated mating disruption (MD) is based on the release of synthetic sex attractants into a crop, interfering with mate finding of a given pest species. However, a limited number of research items have been published on the optimization of MD strategies against the European grapevine moth, Lobesia botrana, as well as on the use of biodegradable dispensers to reduce waste production in vineyards, despite the high economic importance of this pest. Therefore, the present study evaluated the efficacy of the MD products Isonet® L TT and the biodegradable Isonet® L TT BIO, applied at various densities, in reducing L. botrana damage on grapevine in comparison to an untreated control and the reference MD product Isonet® L. Experiments were conducted in three different areas of grapevine cultivation, located in Central and Northern Italy, over three different years. Our MD approach allowed a reliable control of the three generations of L. botrana during the whole grape growing season, leading to a significant reduction in the infested flower clusters and bunches, as well as in the number of nests per flower cluster and bunch, if compared to the untreated control. The performances of Isonet® L TT BIO, Isonet® LTT, and Isonet® L did not differ in terms of infested flower clusters/bunches, as well as nests per flower cluster/bunch. This was confirmed in all experimental sites over 3 years of field experiments. Overall, the present research provides useful information for the optimization of MD programs against L. botrana, highlighting the interesting potential of biodegradable pheromone dispensers that can be easily applied at low densities in vineyards, reducing the use of chemical pesticides to control moth pests.

In this study, shrimp waste was enzymatically hydrolyzed to generate a green dispersant and the product was tested for crude oil dispersion in seawater. The hydrolysis process was first optimized based on the dispersant effectiveness (DE) of the product. The functional properties of the product were identified including stability, critical micelle concentration, and emulsification activity. Water was confirmed as a good solvent for dispersant generation when compared with three chemical solvents. The effects of salinity, mixing energy, and temperature on the dispersion of the Alaska North Slope (ANS) crude oil were examined. Microtox acute toxicity test was also conducted to evaluate the toxicity of the produced dispersant. In addition, DE of the product on three different types of crude oil, including ANS crude oil, Prudhoe Bay crude oil (PBC), and Arabian Light crude oil (ALC) was compared with that of the Corexit 9500, respectively. The research output could lead to a promising green solution to the oil spill problem and might result in many other environmental applications.