Sintering and steel production as the main emission sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may affect environment and human health. The concentrations, profiles, and distributions of PCDD/Fs in soil samples from around four typical sintering and steel production plants in Hebei Province, China, were determined. Forty-six soil samples were collected at distances from 500 to 9000 m from industrial plant chimneys. The concentrations of total 17 2,3,7,8-substituted PCDD/F congeners in the soil samples from sites A, B, C, and D were in the range 11–130, 13–284, 2.6–378, and 21–231 pg/g, respectively, and the internationally accepted toxic equivalent (I-TEQ) concentrations were 0.37–13.2, 0.31–12.1, 0.13–13.7, and 1.60–22.7 pg I-TEQ/g, respectively. Soil ingestion was estimated the major exposure pathway to PCDD/Fs. At current PCDD/F concentrations, the local population will be exposed to low amounts of PCDD/Fs in soil from around the industrial sites, and this exposure will pose potential health risks for the local population living at distances of less than 1000 m from nearest stack but will have no high health risks for people living further away. These results will be helpful when planning measures to control PCDD/F sources. The data will also benefit local environmental monitoring studies and be useful when assessing the risks posed by PCDD/Fs around the industrial sites to the environment and humans.

Nowadays, petrochemical operations involve risks to the environment and one of the biggest is oil spills. Low molecular aromatics like benzene, toluene, and naphthalene dissolve in water, and because of their toxicological characteristics, these produce severe consequences to the environment. The oil spill cleanup strategies are mainly designed to deal with the heavy fractions accumulated on the water surface. Unfortunately, very limited information is available regarding the treatment of dissolved fractions.A commercial (Filtrasorb 400) and modified activated carbons were evaluated to remove benzene, toluene, and naphthalene from water, which are the most soluble aromatic hydrocarbons, at different ionic strengths (I) and temperatures (0–0.76 M and 4–25 °C, respectively). This allowed simulating the conditions of fresh and saline waters when assessing the performance of these adsorbents. It was found that the hydrocarbons adsorption affinity increased 12 % at a I of 0.5 M, due to the less negative charge of the adsorbent, while at a high I (≃0.76 M) in a synthetic seawater, the adsorption capacity decreased 21 % that was attributed to the adsorbent’s pores occlusion by water clusters. Approximately, 40 h were needed to reach equilibrium; however, the maximum adsorption rate occurred within the first hour in all the cases. Moreover, the hydrocarbons adsorption and desorption capacities increased when the temperature augmented from 4 to 25 °C. On the other hand, thermally and chemically modified materials showed that the interactions between adsorbent-contaminant increased with the basification degree of the adsorbent surface.

The large estuary that the River Po forms at its confluence into the Adriatic Sea comprises a multitude of transitional environments, including coastal lagoons. This complex system receives the nutrients transported by the River Po but also its load of chemical contaminants, which may pose a substantial (eco)toxicological risk. Despite the high ecological and economic importance of these vulnerable environments, there is a substantial lack of information on this risk. In light of the recent amendments of the European Water Framework Directive (2013/39/EU), the present study investigated the sediment contamination of six coastal lagoons of the Po delta and its effects on Manila clams (Ruditapes philippinarum), exposed in situ for 3 months. Sediment contamination and clam bioaccumulation of a wide range of chemicals, i.e. trace metals (Cd, Cr, Ni, Hg, Pb, As), polybrominated diphenyl ethers (PBDEs), alkylphenols (APs), organochlorine compounds (PCBs, DDTs), polycyclic aromatic hydrocarbons (PAHs) and organotins (TPhT, TBT), suggested a southward increase related to the riverine transports. Where the River Po influence was more direct, the concentrations of contaminants were higher, with nonylphenol and BDE-209 exceeding sediment quality guidelines. Biometric indicators suggested the influence of contamination on organism health; an inverse relationship between PBDEs in sediments and clam condition index has been found, as well as different biota-sediment accumulation factors (BSAFs) in the lagoons.

Food waste is the largest constituent of municipal solid waste in Hong Kong, but food waste recycling is still in its infancy. With the imminent saturation of all landfill sites by 2020, multiple technologies are needed to boost up the food waste recycling rate in Hong Kong. Conversion of food waste into animal feeds is prevalent in Japan, South Korea, and Taiwan, treating over 40 % of their recycled food waste. This direction is worth exploring in Hong Kong once concerns over food safety are resolved. Fortunately, while feeding food waste to pigs and chickens poses threats to public health, feeding it to fish is considered low risk. In order to examine the feasibility of converting food waste into fish feed in Hong Kong, this paper investigates the market demand, technical viability, feed quality, regulatory hurdles, and potential contribution. The results show that a significant amount of food waste can be recycled by converting it into fish feed due to the enormous demand from feed factories in mainland China. Two conversion technologies, heat drying and black soldier fly bioconversion, are studied extensively. Black soldier fly bioconversion is preferable because the end-product, insect powder, is anticipated to gain import approval from mainland China. The authors suggest further research efforts to speed up its application for food waste recycling in urban cities.

N-doped ZnO (N-ZnO) and N-doped ZrO₂ (N-ZrO₂) are synthesized by novel, simple thermal decomposition methods. The catalysts are evaluated for the degradation of rhodamine 6G (R6G) under visible and UV light. N-ZnO exhibits higher dye degradation under both visible and UV light compared to N-ZrO₂ due to possessing higher specific surface area, lower crystalline size, and lower band gap. However, it is less reusable than N-ZrO₂ and its photocatalytic activity is also deteriorated at low pH. At the same intensity of 3.5 W/m², UVC light is shown to be a better UV source for N-ZnO, while UVA light is more suitable for N-ZrO₂. At pH 7 with initial dye concentration of 10 mg/L, catalyst concentration of 1 g/L, and UVC light, 94.3 % of R6G is degraded by N-ZnO within 2 h. Using UVA light under identical experimental conditions, 93.5 % degradation of R6G is obtained by N-ZrO₂. Moreover, the type of light source is found to determine the reactive species produced in the R6G degradation by N-ZnO and N-ZrO₂. Less oxidative reactive species such as superoxide radical and singlet oxygen play a major role in the degradation of R6G under visible light. On the contrary, highly oxidative hydroxyl radicals are predominant under UVC light. Based on the kinetic study, the adsorption of R6G on the catalyst surface is found to be the controlling step.

Straw management during fallow season may influence crop productivity, soil quality, and greenhouse gas (GHG) emissions from rice field. A 3-year field experiment was carried out in central China to examine the influence of different fallow season straw management practices on rice yield, soil properties, and emissions of methane (CH₄) and nitrous oxide (N₂O) from a mono-rice cultivation system. The treatments comprised an unfertilized control (CK), inorganic fertilization (NPK), rice straw burning in situ (NPK + RSB), rice straw mulching (NPK + RSM), and rice straw strip mulching with green manuring (NPK + RSM + GM). The maximum rice yield, soil organic carbon, soil total nitrogen, and available potassium were observed in NPK + RSM + GM treatment. Compared with NPK, the NPK + RSM + GM recorded 9 % higher grain yield averaged across 3 years. However, NPK + RSM and NPK + RSB were statistically similar with NPK regarding grain yield. The NPK + RSM and NPK + RSM + GM recorded significantly higher CH₄ emission during rice growing season as well as winter fallow; however, the response of N₂O emissions was variable. The NPK + RSM and NPK + RSM + GM were statistically similar for annual cumulative CH₄ and N₂O emissions. The NPK + RSM + GM recorded 103 and 72 % higher straw-induced net economic benefits and soil organic carbon sequestration rate, and reduced net global warming potential by 27 % as compared with NPK + RSM. Considering the benefits of soil fertility, higher crop productivity, and environmental safety, the NPK + RSM + GM could be the most feasible and sustainable option for mono-rice cultivation system in central China.

Hybrid constructed wetland (HCW) systems have been used to treat various wastewaters across the world. However, large-scale applications of HCWs are scarce, particularly for on-site improvement of the water quality of highly polluted urban rivers in semi-arid regions. In this study, a large pilot-scale HCW system was constructed to improve the water quality of the Zaohe River in Xi’an, China. With a total area of about 8000 m², the pilot HCW system, composed of different configurations of surface and subsurface flow wetlands, was operated for 2 years at an average inflow volume rate of 362 m³/day. Local Phragmites australis and Typha orientalis from the riverbank were planted in the HCW system. Findings indicate a higher treatment efficiency for organics and suspended solids than nutrients. The inflow concentrations of 5-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), suspended solids (SS), total nitrogen (TN), NH₃-N, and total phosphorus (TP) were 125.6, 350.9, 334.2, 38.5, 27.2, and 3.9 mg/L, respectively. Average removal efficiencies of 94.4, 74.5, 92.0, 56.3, 57.5, and 69.2 %, respectively, were recorded. However, the pollutant removal rates were highly seasonal especially for nitrogen. Higher removals were recorded for all pollutants in the autumn while significantly lower removals were recorded in the winter. Plant uptake and assimilation accounted for circa 19–29 and 16–23 % of the TN and TP removal, respectively. Moreover, P. australis demonstrated a higher nutrient uptake ability and competitive potential. Overall, the high efficiency of the pilot HCW for improving the water quality of such a highly polluted urban river provided practical evidence of the applicability of the HCW technology for protecting urban water environments.

Heavy metals in urban soils may pose risks to both urban environment and human health. However, only a fraction of heavy metals in soil is mobile and/or bioavailable for plant uptake and human ingestion. This study evaluates the chemical fraction and potential mobility and bioaccessibility of heavy metals (Cd, Cr, Cu, Pb, and Zn) in the contaminated urban topsoils from steel-industrial city (Anshan), Northeastern China. Chemical forms of heavy metals in soils are determined using Tessier sequential extraction technique. The toxicity characteristic leaching procedure (TCLP), ethylenediaminetetraacetic acid (EDTA), and US Pharmacopeia methodology (USPM) are used to determine the operationally defined potentially mobile and bioaccessible metal fractions, respectively. Sequential extraction results show that Cd has the highest percentage of exchangeable form, whereas Cr primarily exists in residual form. The non-residual fraction of heavy metals increases in the order of Cr < Cu < Pb < Zn < Cd. The leachability of heavy metals evaluated by TCLP test indicates that Cd, Zn, Cu, and Pb have much higher mobile than Cr. The bioavailability of heavy metals determined by EDTA extraction decreases in the order of Pb > Cu ≅ Zn > Cd > Cr. The order of bioaccessibility determined by USPM extraction is Pb = Cu > Zn > Cd > Cr. The Cr exhibits the lowest leachability and bioaccessibility among the investigated metals. The Pb has the highest bioaccessibility, indicating higher potential hazard for the human health. There are significant relationships between the EDTA- and USPM-extractable metals (Cd, Cu, Pb, and Zn) and the sum of first three steps of sequential extraction. Highly significant correlation is found between amounts of EDTA-extractable Cd, Cu, Pb, and Zn and USPM-extractable metals. The result suggests that EDTA extraction can be helpful to estimate the bioaccessibility of heavy metals for human ingestion. Introduction of mobile and human bioaccessible concentrations into risk assessments can give more realistic implications for urban environmental management.

There is a growing concern over the use of antibiotics due to the increased resistance of pathogens in broiler. The present study was designed to find the comparative effect of an antibiotic, and some phytogenic on performance traits, blood biochemical parameters, and antioxidant status during starter phase exposed to Salmonella typhimurium challenge. A total of 560-day-old broiler chicks (Ross 308) were randomly allocated to seven treatments (eight replicates). Control (basal diet); T1, infected with Salmonella enterica subsp. typhimurium; T2, infected + avilamycin at the rate of 0.2 g/kg; T3, infected + essential oil of thymol; T4, infected + phytogenic; T5, infected + anti-Salmonella organic acid; and T6, infected + essential oils of thyme, anise, and other components. Body weight gain and feed conversion ratio (FCR) were significantly (P < 0.05) high in the T2 and T5 at the end of the first and the second week and similar to T4. During the second week, European production efficiency factor (EPEF) was also significantly (P < 0.05) high in T2, T4 and T5. Blood albumin increased significantly (P < 0.05) in birds of T2 in the first week, while during the second week, blood glucose and triglyceride concentration decreased significantly (P < 0.05) in T5. Blood ALT concentration decreased significantly (P < 0.05) in T6 compared to other treatments in the second week. Total antioxidant capacity (at the end of the second week) and thiobarbituric acid reactive substances (TBARS) did not change significantly. From the results of the present study, it was concluded that different feed additives could be substituted with antibiotics in the feed of broiler exposed to S. typhimurium challenge.

In the context of an oil spill accident and the following oil spill response, much attention is given to the use of dispersants. Dispersants are used to disperse an oil slick from the sea surface into the water column generating a cloud of dispersed oil droplets. The main consequence is an increasing of the sea water–oil interface which induces an increase of the oil biodegradation. Hence, the use of dispersants can be effective in preventing oiling of sensitive coastal environments. Also, in case of an oil blowout from the seabed, subsea injection of dispersants may offer some benefits compared to containment and recovery of the oil or in situ burning operation at the sea surface. However, biological effects of dispersed oil are poorly understood for deep-sea species. Most effects studies on dispersed oil and also other oil-related compounds have been focusing on more shallow water species. This is the first approach to assess the sensitivity of a macro-benthic deep-sea organism to dispersed oil. This paper describes a toxicity test which was performed on the macro-benthic deep-sea amphipod (Eurythenes gryllus) to determine the concentration causing lethality to 50 % of test individuals (LC₅₀) after an exposure to dispersed Brut Arabian Light (BAL) oil. The LC₅₀ (24 h) was 101 and 24 mg L⁻¹ after 72 h and 12 mg L⁻¹ at 96 h. Based on EPA scale of toxicity categories to aquatic organisms, an LC₅₀ (96 h) of 12 mg L⁻¹ indicates that the dispersed oil was slightly to moderately toxic to E. gryllus. As an attempt to compare our results to others, a literature study was performed. Due to limited amount of data available for dispersed oil and amphipods, information on other crustacean species and other oil-related compounds was also collected. Only one study on dispersed oil and amphipods was found, the LC₅₀ value in this study was similar to the LC₅₀ value of E. gryllus in our study. Since toxicity data are important input to risk assessment and net environmental benefit analyses, and since such data are generally lacking on deep-sea species, the data set produced in this study is of interest to the industry, stakeholders, environmental management, and ecotoxicologists. However, studies including more deep-sea species covering different functional groups are needed to evaluate the sensitivity of the deep-sea compartments to dispersed oil relative to other environmental compartments.