Most of the chemicals containing non-biodegradable metal pollutants from anthropogenic sources are highly mobile in nature. The only way to contain or limit their movement is through sorption and entrapment in the soil matrices. In this study, the sorptive response of the three most commonly found divalent metal contaminants, copper (Cu⁺²), lead (Pb⁺²), and zinc (Zn⁺²), are studied using two locally available semi-arid soils from Saudi Arabia. To enhance their retention capacity, these soils are amended with lime. The response to sorption at varying initial contaminant concentrations, pH conditions, temperature levels, and dilution ratios are investigated. Relying on empirical models (Langmuir and Freundlich), the nature of sorption (monolayer or heterogeneous) is ascertained. Further, kinetic models are employed to validate the type and nature of sorption that occurs (whether pseudo first-order or second-order). It is found that the experimental results correlate well with these empirical models for both the Al-Ghat and Al-Qatif soils when amended with lime and attenuate Cu, Pb, and Zn to satisfactory levels. The R ² values are close to 1 for all the tested models. The order of sorption was Pb > Cu > Zn for these heavy metals, and also for soils and soil mixtures that were considered: Al-Qatif soil amended with 6 % lime > Al-Ghat soil with 6 % lime > Al-Qatif > Al-Ghat. Lime-treated soils sorbed 73, 65, and 60 % more than the untreated soils for Pb, Cu, and Zn, respectively.

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.

Particulate matter is an air pollutant that has resulted in tremendous health effects to the exposed populace. Air quality forecasting is an established process where air pollutants particularly, particulate matter (PM₁₀) concentration is predicted in advance, so that adequate measures are implemented to reduce the health effect of PM₁₀ to the barest level. The present study used daily average PM₁₀ concentration and meteorological parameters (temperature, humidity, wind speed and wind direction) for 5 years (2006–2010) from three industrial air quality monitoring stations in Malaysia (Balok Baru, Tasek and Paka). Time series plot was used to assess PM₁₀ pollution trend in the industrial areas. Additionally, step wise regression (SWR) analysis was used to predict next day PM₁₀ concentrations for the three industrial areas. The SWR method was compared with a persistence model to assess its predictive capabilities. The results for the trend analysis showed that, Balok Baru (BB) had higher PM₁₀ concentration levels, having high values in 2006, 2007 and 2009. These values were higher than the Malaysian Ambient Air Quality Guideline (MAAQG) of 150 μg/m³. Subsequently, the other two industrial areas Tasek (TK) and Paka (PK) had no record of violating the MAAQG. The results for the SWR analysis had significant R ² values of 0.64, 0.66 and 0.60, respectively. The model performance results for variance inflation factor (VIF) were less than 5 and Durbin-Watson test (DW) had value of 2 for each of the study areas, which were significant. The comparative analysis between SWR and persistence model showed that the SWR had better capabilities, having lower errors for the BB, TK and PK areas. Using root mean square error (RMSE), the results showed error differences of 7, 12 and 16 %, and higher predictability using index of agreement (IA), having a difference of 17, 19 and 16 % for BB, TK, and PK areas, respectively. The results showed that SWR can be used in predicting PM₁₀ next day average concentration, while the extreme event detection results showed that 100 μg/m³ were better detected than the 150 μg/m³ bench marked levels.

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.

The primary goal of this research was to evaluate the effect of a ternary mixture of toluene, methanol, and trichloroethylene (TCE) on the elimination of TCE in a biotrickling filter. Two biotrickling filters—Biofilter I and Biofilter II—were run in parallel, each with a different toluene/methanol/TCE loading ratio of 3:2.7:1 and 1.9:0.9:1, respectively. Both systems were seeded with fungal strains grown on diatomaceous earth media and were run at pH 4 maintained by formate buffer. To control excess biomass growth, the systems were “starved” for 2 days a week and run continuously for the rest of the week. TCE loading rates for each system ranged from 1.61 to 6.44 g/m³ h⁻¹ across three phases while toluene and methanol were loaded at rates corresponding to the influent composition ratios. More than 95 % methanol was removed from the gaseous streams throughout, while TCE removal was a function of the influent organic ratio and the corresponding concentrations. At and above loading rates of 3.22 g/m³ h⁻¹, elimination capacities obtained from Biofilter II surpassed those from Biofilter I due to a lower feed of bio-accessible carbon (toluene and methanol) offering reduced competition to TCE removal. While over 90 % toluene was removed from both systems, its elimination capacities dropped as the phases progressed due to competition and TCE cytotoxicity. Most carbon was converted to CO₂ and biomass, and no TCE oxidation by-products were detected.

The presence of surfactants in groundwater and in drinking and superficial waters is a major public health concern. Recently, various treatment technologies have been studied to remove these pollutants; among them, the treatments based on the sorption onto natural adsorbing materials appear more eco-friendly and with very interesting removal efficiencies. The sorption of the cationic surfactant benzyldimethyldodecyl ammonium chloride (BDC-12) onto zeolitic tuff (Si/Al ratio = 2.4) was well described by a pseudo-second-order equation with a kinetic constant not depending on the exchangeable cationic form of the zeolite. The isosteric enthalpies and entropies (∆ᵢₛₜH and ∆ᵢₛₜS) obtained from sorption isotherms were negative, and their absolute values increased with decreasing amounts of BDC-12 bound at the equilibrium (qₑ). Zeolite sorbitivity (qₑ/unit dry mass sorbent) for BDC-12 increased with NaCl concentration in the batch solution, suggesting that the sorption process does not involve cation exchange.

The current experiment was conducted to evaluate the effects of feeding dried sweet orange peel (SOP) and lemon grass leaves (LGL) as feed additives on broiler growth performance, serum metabolites, and antioxidant status. A total of 192-day-old (Ross 308) broiler chickens were distributed randomly into 4 dietary treatments with 4 replicates per each treatment. The dietary treatments included a control diet without any feed additive (T1), a diet containing 0.8 % SOP (T2), a diet containing 0.8 % LGL (T3), and a diet containing combination of 0.4 % SOP + 0.4 % LGL (T4) was fed during the growth period from 22 to 42 days. Feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), carcass traits, serum components, and antioxidant status were measured. At the end of the experimental period, the results indicated that supplementation of SOP and LGL alone or in combination did not significantly (P > 0.05) affect BWG, FI, FCR, and carcass characteristics in broiler chickens. Serum total protein was increased significantly (P < 0.05) in T3 and T4 compared to the other treatments. Also, serum globulin increased significantly (P < 0.05) in the treated groups. Serum glucose, low density lipoprotein, triglyceride, and very low density lipoprotein decreased significantly (P < 0.05) in the treatment groups, while cholesterol and high-density lipoprotein decreased in T2 compared to the other groups. Significantly (P < 0.05) higher total antioxidant status was observed in T2 compared to the other treatments. In conclusion, these results indicate that SOP, LGL, and their combination may positively modify some serum components and the antioxidant status without any beneficial effect on growth performance and carcass traits in broiler chickens.

Using an indoor microcosm assay, we analyzed the biodegradation of total petroleum hydrocarbons (TPHs) by autochthonous bacterial populations in mining soil in the presence of a surfactant (Tween 80). The kinetic behavior of TPH biodegradation involved fast and slow stages. Initially, heterotrophic and hydrocarbonoclastic bacteria increased in abundance by an order of magnitude, but both groups decreased to close to their initial population sizes by the end of experiment. The most efficient final biodegradation (61.5 %) was achieved using soil with 0.5 % added surfactant. Polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) were used to analyze changes in the bacterial community structure. During the fast biodegradation phase, bacterial species richness as indicated by DGGE profiles was reduced after long periods of TPH biodegradation with exposure to Tween 80. The distribution of families was modified, but no particular pattern could be identified. The main bacterial genera were Acinetobacter, Pedomicrobium, Halomonas, Rhizobium, Cryobacterium, Pseudomonas, Lysobacter, Thermomonas, and Stenotrophomonas. Acinetobacter exhibited the highest species richness and was the most abundant and persistent genus, followed by Pedomicrobium and Rhizobium. Decreasing TPH biodegradation can be attributed to a reduction in the microbial population and the disappearance of most of the initial bacterial genera. The correlation between TPH biodegradation and microbial population dynamics helps explain long bioremediation times and can facilitate actions for increasing bioremediation efficiency.

To study the impact of biological treatment techniques on perfluoroalkyl acids (PFAAs) emissions in municipal sewage, high-performance liquid chromatography-tandem mass spectrometry was combined with WAX extraction enrichment to analyze the content and distribution of 14 PFAAs in the influent and effluent of 10 municipal sewage treatment plants that adopted 3 biological treatment techniques including sequencing batch reactor (SBR), oxidation ditch, and A/O-involved processes in Shenzhen, China. The mass flow of PFAAs under different biological treatment techniques was also compared. Results showed that average ΣPFAAs of the ten sewage treatment plants decreased from 32 to 26 ng/L after treatment, showing no significant difference, but average daily ΣPFAAs mass flow significantly decreased from 8.1 to 6.1 g/day (p < 0.05). Through treatment, short-chain PFAAs and perfluoroalkyl carboxylic acids (PFCAs) with removal rates of 43 and 29 % decreased significantly (p < 0.01), but long-chain PFAAs and perfluorosulfonates (PFSAs) with removal rates of −0.68 % and −21 % did not. The plants using SBR had an average ΣPFAAs removal rate of 35 %, comparable to those using A/O-involved processes (27 %). However, the plants using oxidation ditch technique had an average long-chain PFAAs removal rate of −51 %, making their average ΣPFAAs removal rates reaching −25 %, significantly lower than the other two techniques (p < 0.05).

The aim of the present study was to evaluate if increased Cu and Zn concentrations in soils, as a consequence of distribution at the field level for 10 consecutive years of pig slurry (PS) and pig deep litter (DL), would cause toxicity to maize plants affecting, in turn, the biomass production and grain yield. With this aim, maize was grown in two cycles in undisturbed samples from soil that had been fertilized with annual applications of 90 or 180 kg N ha⁻¹, either as PS or DL, in a field experiment carried out for 10 years in southern Brazil. The PS180 and DL180 treatments resulted in Cu and Zn accumulation in soil, and PS180 resulted in Zn accumulation in the tissue of maize plants. The increased availability of Cu and Zn was associated to slight changes in stomatal density, chlorophyll content, and catalase and ascorbate peroxidase activities. Nevertheless, soluble carbohydrate and protein contents and plant dry matter accumulation were not significantly affected by exposure of plants to those high levels of either metal. The results here presented indicate that, although successive applications of PS and DL resulted in a really considerable increase of Cu and Zn in the soils, they do not cause toxic effects in maize plants as to impair their ability to produce biomass and grain.