Featured with biodegradability and biocompatibility properties, gelatin (GE) was selected as the backbone to graft poly(acrylic acid) (PAA) to fabricate a granular hydrogel at room temperature in air. Using attapulgite (APT) as an inorganic component, the resulting GE-g-PAA/APT hydrogel was characterized by means of Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and zeta potential analysis and then used as the adsorbent to be applied in a mixed dye solution containing malachite green and orange G. The addition of APT can significantly reduce the swelling degree during the adsorption process, though its influences on the adsorption capacity are not so expectable. The as-prepared hydrogel shows a wide pH-independent adsorption from 3.0 to 10.0, with the maximum adsorption capacity of 1370 mg/g for GE-g-PAA and 1190 mg/g for GE-g-PAA/APT (5 wt%). More importantly, the as-prepared hydrogel shows high adsorption selectivity for cationic dyes and the dye-loaded hydrogel can be easily regenerated and recovered for successive adsorption cycles. Graphical Abstract Gelatin-based granular hydrogel for selective removal of MG in a mixed dyes containing MG and OG-G.

In this work, metal sorption onto grape stalks waste structural compounds and extractives has been studied for determining their role in Cr(VI), Cu(II) and Ni(II) metal sorption. For this purpose, a sequential extraction of extractives and other compounds from the lignocellulosic material has been carried out. The resulting solid samples obtained in the different extraction processes were used as sorbents of Cr(VI), Cu(II) and Ni(II). Sorption results were discussed taking into account the elemental composition and polarity of the solid extracts. Results indicated that tannins and polyphenols are involved in chromium reduction and sorption. Lignin and celluloses are involved in chromium, Cu(II) and Ni(II) sorption. FTIR analysis confirmed the involvement of lignin moieties in the studied metal ions sorption by grape stalks waste. This study presents a new approach on metal sorption field as the knowledge of the role of the sorbent chemical compounds is essential to determine the key sorbent compounds in the sorption process.

To facilitate the mapping of pollution fluxes under different flow conditions when a limited number of gauging stations are available, a method relying on geographic data was developed to estimate the mean daily stream discharge at each sampling station. It has been tested on a rural river watershed that is located in northeast France (Madon River). The stretch of 100 km is equipped with three gauging stations. Surface water samples were collected at 30 stations under different flow conditions. In a participatory research project, samples were also collected by school children at one of the stations (once a week during the school year over a 2-year period). Dissolved organic carbon and nitrogen species were measured for all samples. These data illustrate the variation in the pollution in the river that is associated with agricultural activities and discharges of untreated wastewater. This method was used to obtain localized points of nutrient discharge, to identify the zones that favor nutrient removal, and to propose remediation work.

Sediment, suspended particulate matter (SPM), water and clam Scrobicularia plana samples were collected in a temperate coastal lagoon with anthropogenic impact. Arsenic levels in sediments, SPM and water presented a spatial concentration gradient. A significant linear regression between arsenic levels in S. plana and SPM suggests particulate matter as the main route of arsenic exposure. Trend analysis showed that total arsenic concentrations in S. plana generally increased with size class, reflecting lifespan bioaccumulation. Despite being efficient in reflecting environmental contamination levels, results suggest that arsenic accumulation by S. plana may not be a passive process, given the proportionally lower accumulation in high contamination areas. Annual bioaccumulation rates ranged from 5.6 to 1 mg kg⁻¹ year⁻¹, suggesting a possible toxicity risk for individuals of the most contaminated area. Despite the absence of regulatory guidelines, food safety assessment highlighted possible adverse effects of consuming S. plana in most contaminated areas.

Plant peroxidases have strong potential utility for decontamination of phenol-polluted wastewater. However, large-scale use of these enzymes for phenol depollution requires a source of cheap, abundant, and easily accessible peroxidase-containing material. In this study, we show that potato pulp, a waste product of the starch industry, contains large amounts of active peroxidases. We demonstrate that potato pulp may serve as a tool for peroxidase-based remediation of phenol pollution. The phenol removal efficiency of potato pulp was over 95 % for optimized phenol concentrations. The potato pulp enzymes maintained their activity at pH 4 to 8 and were stable over a wide temperature range. Phenol solutions treated with potato pulp showed a significant reduction in toxicity compared with untreated phenol solutions. Finally we determined that this method may be employed to remove phenol from industrial effluent with over 90 % removal efficiency under optimal conditions.

Long-term fire retardant (LTR) use for forest fire suppression and/or prevention purposes can result in chemical leaching, from soil to the drainage water, during the annual rainfall period. Also, wildland fires can have an impact on the leaching of various chemicals from treated forest soils. Large quantities of ions in leachates, mainly due to ammonium (one of the major LTR components) soil deposition, could affect the groundwater quality. The alteration of pH, total hardness (TH), and electrical conductivity (EC) values in leachates mainly due to nitrogen-based LTR application (Fire Trol 931) was investigated in this laboratory study. The values of pH, TH, and EC were measured in the resulting leachates from pots with forest soil and pine trees alone and in combination with fire after a simulated rainfall period. pH, TH, and EC values in leachates from all treated pots were significantly greater than those from control pots.

In this experiment, air and nutrients were injected into a low temperature heavy oil reservoir to initiate an indigenous microbial enhanced oil recovery (MEOR) process with a cumulative increment of 1872 t heavy oil. This study reveals the response of microbial communities in the field before and during MEOR based on culture-dependent enrichment and culture-independent 16S rRNA gene clone library methods. The results showed that it was easy to activate the biosurfactant-producing bacteria Pseudomonas in laboratory conditions, and the bacteria were also the dominant present group in the mixed oil-water samples after MEOR. Fermentative and hydrocarbon-oxidizing bacteria increased by 300-500%, and the acetate ion concentration also significantly increased. Microbial activity of Pseudomonas and the metabolic products including biosurfactants were proposed to be the primary mechanisms for improving heavy oil recovery. The results of this experiment can serve as a useful resource for monitoring MEOR-related microbial population, and for future related experiments.

The sediments in a ditch may be altered from phosphorus source to the sink, or vice-versa. This study examined the effects of pH, dissolved oxygen (DO), and light intensity on the amount of phosphorus release. Phosphate is most susceptible to the adsorption by sediment when the pH is 7, while phosphorus release is greater in the alkaline range and reduced in acidic conditions. The interception of microorganisms in ditches also plays an important role on phosphorus release from sediments. An oxygen-rich environment was conducive to the sorption of phosphate in overlying water, while an anoxic environment provided the opposite effect. Correspondingly, the NaOH-P emissions from sediments were greater under anoxic conditions than under oxic conditions. Light intensity also had a major effect in the overlying water on pH and ORP, further to work on phosphorus release from ditch sediments. The correlation between the light intensity and the quality of phosphorus release in the sediments was not obvious.

Every day, millions of agricultural workers are exposed to noise at work and all the risks this can entail. The World Health Organization (WHO) states “noise-induced hearing loss is insidious, permanent and irreparable”. By using power tiller, more than the permissible exposure limit to noise may cause serious health problems to the agricultural workers. This paper examines the noise propagation of popular and most commonly used power tillers having a power rating of 11kW, 9.5kW and 4.4 kW. It was observed that all three power tillers produced the noise above 93 dB(A) in the working zone of the operator. The density of noise contour and SPL is proportional to the engine rpm or load. The working radius around PT-I, PT-II and PT-III of 3.5 m, 2 m and 5.6 m was found noisy [>90 dB(A)] and not suitable to work 8 h per day as per recommendation of ISO and OSHA. The permissible duration of exposure to noise for operator for PT-I, PT-II and PT-III varies from 7.8 h to 3.6 h, 13 h to 5.1 h and 5.3h to 2.1h, respectively for different engine rpm.

Environmental problems in rural areas of China can be fundamentally solved by preventing and controlling agricultural chemical pollution. On the basis of local and foreign literature, the current research used relevant statistical data regarding the use of chemical fertilizers from 1993 to 2013 and the use of agricultural films and pesticides from 1993 to 2012. Then, the paper adopted SSPS calculation, comparative analysis, and chart analysis methods to analyse the status quo of China’s agricultural chemical pollution. Results show that between 1993 and 2013, the total amount of fertilizers used in 31 provinces and cities of China has significantly increased, and the intensity of fertilizer use increases yearly. Moreover, the number of provinces that exceeded the international standard for fertilizer use (225 kg/hm2) has increased from 8 to 28. During the same period, the ratio of fertilizer use in China has changed but remained far from scientific use. Furthermore, the use of agricultural films and pesticides between 1993 and 2012 has assumed an upward trend. Overall, China’s agricultural chemical pollution becomes increasingly serious, thereby endangering the rural environment and agricultural resources and threatening human health and life. As such, this study conducted a unique and in-depth analysis from an institutional perspective and provided countermeasures and recommendations for the institutional transition of China in terms of prevention and control of agricultural chemical pollution.