Untreated arsenic polluted groundwater is threatening people health, especially the people in rural areas. Soil may become one kind of promising natural material applied conveniently in rural areas for the treatment of arsenic polluted groundwater, due to its abundance, low cost, and high adsorption efficiency. The present study investigated arsenic(V) (As(V)) adsorption on two red soil samples weathered from granite (RSG) and sandstone (RSS). The two soil samples contain similar mineral types but show relatively high differences of content of iron, aluminum, and organic matter (OM), as well as point of zero charge (pHPZC) and specific surface area (SSA). Batch experiments were performed to examine the effect of initial As(V) concentration, solution pH, and temperature on the kinetics of the adsorption of As(V) by the two soil samples. The experimental results showed that the As(V) adsorption onto the two soil samples was influenced by the physicochemical properties of the soils, especially the content of iron and aluminum, the OM, as well as the pHPZC, and chemisorption was the main adsorption mechanism. The RSG sample with higher content of iron and aluminum and pHPZC showed relatively high adsorption efficiency. The OM played a negative role in the adsorption process, especially as the As/Fe molar ratio is higher. Higher adsorption capacities for the two soil samples were both obtained at lower initial As(V) concentration (1.50 and 4.0 mg/l), lower pH value (5.0), and higher temperature (313 K). Comparing to the RSS, the RSG is more suitable for the treatment of As(V)-polluted groundwater. Considering the experimental results and the natural conditions, the suggested operational conditions are pH around 7.0, temperature 293–303 K, As(V) concentration less than 4.0 mg/l, and hydraulic retention time no less than 180 min.

Anthropic eutrophication is one of the most widespread problems affecting water quality worldwide. This condition is caused by excessive nutrient inputs to aquatic systems, and one of the main consequences is accelerated phytoplankton growth. Eutrophication can lead to damage to human health, the environment, society, and the economy. One of the most serious consequences of eutrophication is the proliferation of cyanobacteria that can release toxins into the water. The aim of this research was to evaluate the trophic condition of a tropical reservoir over the course of time, using a database extending over 15 years to investigate relationships with environmental conditions, considering spatial heterogeneity and seasonality, as well as inter-relations between trophic state indicators. Data for chlorophyll-a, total phosphorus, and total nitrogen were collected from 2000 to 2014, and cyanobacteria abundance was determined from 2004 to 2014. The trophic state index was also calculated. The results demonstrated the existence of two distinct compartments in the reservoir: one lotic and the other lentic. No relationship was observed between chlorophyll-a and phosphorus. The results suggested that phytoplankton growth was mainly controlled by nitrogen concentrations. These conditions favored cyanobacteria predominance, resulting in increasing abundance of these potentially toxic bacteria over time. The model obtained indicated hypereutrophic conditions, with high phytoplankton biomass and cyanobacteria abundance during the next years likely to affect the uses of the water of the reservoir.

Aerosol optical properties were measured and analyzed through the ground-based remote sensing Aerosol Robotic Network (AERONET) over an urban-industrial site, Nanjing (32.21° N, 118.72° E, and 62 m above sea level), in the Yangtze River Delta, China, during September 2007–August 2008. The annual averaged values of aerosol optical depth (AOD₅₀₀) and the Ångström exponent (AE₄₄₀–₈₇₀) were measured to be 0.94 ± 0.52 and 1.10 ± 0.21, respectively. The seasonal averaged values of AOD₅₀₀ (AE₄₄₀–₈₇₀) were noticed to be high in summer (autumn) and low in autumn (spring). The characterization of aerosol types showed the dominance of mixed type followed by the biomass burning and urban-industrial type of aerosol at Nanjing. Subsequently, the curvature (a ₂) obtained from the second-order polynomial fit and the second derivative of AE (α′) were also analyzed to understand the dominant aerosol type. The single scattering albedo at 440 nm (SSA₄₄₀) varied from 0.88 to 0.93 with relatively lower (higher) values during the summer (spring), suggesting an increase in black carbon and mineral dust (desert dust) aerosols of absorbing (scattering) nature. The averaged monthly and seasonal evolutions of shortwave (0.3–4.0 μm) direct aerosol radiative forcing (DARF) values were computed from the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model both at the top of atmosphere (TOA) and bottom of atmosphere (SUR) during the study period. Further, the aerosol forcing efficiency (AFE) and the corresponding atmospheric heating rates (AHR) were also estimated from the forcing within the atmosphere (ATM). The derived DARF values, therefore, produced a warming effect within the atmosphere due to strong absorption of solar radiation.

Difficulties encountered in estimating the biodegradation of poorly water-soluble substances are often linked to their limited bioavailability to microorganisms. Many original bioavailability improvement methods (BIMs) have been described, but no global approach was proposed for a standardized comparison of these. The latter would be a valuable tool as part of a wider strategy for evaluating poorly water-soluble substances. The purpose of this study was to define an evaluation strategy following the assessment of different BIMs adapted to poorly water-soluble substances with ready biodegradability tests. The study was performed with two poorly water-soluble chemicals—a solid, anthraquinone, and a liquid, isodecyl neopentanoate—and five BIMs were compared to the direct addition method (reference method), i.e., (i) ultrasonic dispersion, (ii) adsorption onto silica gel, (iii) dispersion using an emulsifier, (iv) dispersion with silicone oil, and (v) dispersion with emulsifier and silicone oil. A two-phase evaluation strategy of solid and liquid chemicals was developed involving the selection of the most relevant BIMs for enhancing the biodegradability of tested substances. A description is given of a BIM classification ratio (R BIM), which enables a comparison to be made between the different test chemical sample preparation methods used in the various tests. Thereby, using this comparison, the BIMs giving rise to the greatest biodegradability were ultrasonic dispersion and dispersion with silicone oil or with silicone oil and emulsifier for the tested solid chemical, adsorption onto silica gel, and ultrasonic dispersion for the liquid one.

Airborne fine particulate matter (PM₂.₅) from five megacities including Beijing, Tianjin, Shijiazhuang, Baoding, and Jinan were collected during November 2014 and compared with similar periods in 2012 and 2013. The November 2014 period coincided with the Asia Pacific Economic Cooperation (APEC) Leaders Meeting during which measures to control pollution of the air were introduced. Concentrations of 11 elements in PM₂.₅ were quantified by inductively coupled plasma–mass spectrometry (ICP-MS) after microwave-assisted digestion. Potential effects of five toxic trace metals including Mn, Ni, Cu, Zn, Pb, and the metalloid As on health were assessed. In 2014, concentrations of PM₂.₅ were significantly less than during the same period in 2012 and 2013. Mean concentrations of six elements ranked in decreasing order, Zn > Pb > Cu ≈ Mn > As > Ni, and spatial concentrations ranked in decreasing order, Shijiazhuang > Baoding > Tianjin > Jinan > Beijing. Risks of the five metals and the metalloid As to health of humans were small, except for Mn in Shijiazhuang. Risks to health posed by other elements were less during the period of study. Risks posed by the five metals and As in Beijing were greater to varying degrees after the APEC meeting. Risks to health of humans during the APEC were overall lesser than the same period in 2012 and 2013, mostly due to lesser emissions due to the short-term control measures.

The Songhua River (SHR) is one of the seven major rivers in China. It feeds into Heilongjiang River, which is the natural border river between China and Russia. The water quality and security of the border river plays an important role in relations of two countries and the economic development for border region. This article collects the papers about researches on organic pollutant in SHR of recent 40 years. With the research study result, this article analyses organic pollutant change trend in terms of detected category, amount and distribution. It shows that the organic pollution is severe and caused negative impact on ecological environment because of industrial development near river bank during 1970–2000. The water quality of SHR has been improved and changed to slight pollution due to the implementation of basin pollution prevention planning in 21st century. The pollutant categories have decreased with lower concentration trend. This study suggests the research orientation for organic pollution of SHR in the future.

This study investigated the phytoremediation potential of Plantago major L. to remediate lead (Pb) contaminated water and soil. Results of this investigation indicated that P. major L. roots exhibit a significant increase in Pb uptake relative to P. major leaves from polluted water and soil. In polluted water (40 mg/L Pb), P. major showed unusually high concentrations of Pb in their roots (9284.66 mg/kg) within 25 days as the rhizofiltration suggesting that an exclusion strategy for metal tolerance exist widely in him. In soil, P. major has the potential for phytostabilization. In Pb-contaminated soil at 20 mg/kg, P. major roots efficiently accumulated Pb (50.53 mg/kg and 77.12 mg/kg) after 10 and 20 days, respectively. Pb was taken up by P. major leaves to a lesser extent than the roots (13.87 mg/kg and 30.4 mg/kg) after 10 and 20 days, respectively. The results suggest that P. major may be considered a bioaccumulator species for Pb and can be used as a bioindicator of pollution with lead.

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.

This study aims to evaluate extensively the inhibition of six PCB (polychlorinated biphenyls) congeners in batch reactors under fermentative-methanogenic condition. The reactors with anaerobic sludge were fed with mineral medium, co-substrates (ethanol and sodium formate), and five PCB concentrations. The maximum methane production (MMP) in the reactor without PCB (RC), with 0.5 (R0.5), 1.5 (R1.5), 3.0 (R3.0), 4.5 (R4.5), and 6.0 mg/L (R6.0) of PCB, was 654.83, 193.08, 111.65, 104.60, 96.67, and 79.50 μmolCH₄/gTVS, respectively. The methane inhibition for the reactors R0.5, R1.5, R3.0, R4.5, and R6.0 were 70, 83, 84, 85, and 88 %, respectively. The concentration that causes 50 % of inhibition (IC₅₀) for PCB was 0.03 mg/L. The inhibition results present two different profiles according to the concentration range. The concentration range of 0.5 to 3.0 mg/L of PCB inhibited the acetoclastic microorganisms and the concentration of 4.5 to 6.0 mg/L inhibited both methanogenic and acidogenic population. The acidogenic populations were less sensitive to the PCB than the methanogenic. Lower methane production and organic matter removal were verified in all reactors with PCB compared to RC, without PCB. The microbial community highlighted lower diversity index for reactors with higher PCB concentration. In the reactors with PCB, the populations of bacteria domain were more susceptible to composition changes than the archaea domain. The inhibitory effect of PCB is concentration-dependent and affected differently the populations of organisms in the reactor. Moreover, the range of 4.5 to 6.0 mg/L of PCB severely inhibited the anaerobic community.

Copper-based algaecides are used to control algae that compromise uses of lakes and reservoirs. However, there are concerns regarding potential adverse effects to benthic macroinvertebrates following long-term, repeated applications. Multiple lines-of-evidence are useful for evaluating potential ecological risks. These lines-of-evidence are encompassed in the sediment quality triad (SQT) and include sediment copper concentrations, in situ benthic invertebrate abundance, and sediment toxicity testing. The objective of this study was to measure potential ecological risks associated with long-term applications of copper algaecides in coves in Lay Lake, Alabama. Sediments from three coves treated for 7, 10, and 20 years were compared to sediments from three untreated coves in terms of copper concentrations, in situ benthic macroinvertebrate total abundance, and survival of Hyalella azteca and Chironomus dilutus in laboratory sediment toxicity tests. Sediment copper concentrations were not different between treated and untreated coves, with the exception of one treated cove (PC-1S) that contained elevated sediment copper concentrations compared to all other coves. However, the copper was not bioavailable to organisms based on in situ macroinvertebrate abundance and laboratory toxicity tests. In situ benthic invertebrate abundance was not different between treated and untreated coves. In all sediments tested, there were no measurable adverse effects to H. azteca and there were no significant differences in survival of C. dilutus between treated and untreated coves. Based on the weight-of-evidence approach utilized in this study, long-term copper use in three Lay Lake coves has not resulted in adverse effects to benthic invertebrates compared to untreated coves.