Ciprofloxacin (CIP) can be strongly adsorbed by ferric oxides, but some influencing factors, such as multivalent cations and soil organic matter, have not been evaluated extensively. In this study, the interaction between CIP and four divalent metals (Ca, Cd, Cu, and Pb) was investigated using potentiometric titration and the results indicated that CIP can bind to the divalent metals in the following affinity order: Cu(II) > Pb(II) > Cd(II) > Ca(II). The effects of metals and fulvic acid (FA) on the adsorption behavior of CIP onto goethite surfaces were also examined using batch experiments. It was found that metal cations enhanced the CIP retention on goethite surfaces in the same order as the affinity order with CIP, indicating that metals likely increased CIP retention through cation bridging. FA was found to promote CIP sorption rather than compete with it, and the coexistence of FA and Cu(II) in the system exhibited an addictive effect with CIP sorption, indicating that they might influence the sorption separately under the studied loading condition. Taken together, our results suggested that the coexistence of divalent cations or soil organic matter will enhance CIP sorption on goethite surfaces, hence reducing its mobility and bioavailability in the environment.

Constructed wetlands (CWs) have been used as an alternative to conventional technologies for wastewater treatment for more than five decades. Recently, the use of various modified CWs to improve treatment performance has also been reported in the literature. However, the available knowledge on various CW technologies considering the intensified and reliable removal of pollutants is still limited. Hence, this paper aims to provide an overview of the current development of CW strategies and techniques for enhanced wastewater treatment. Basic information on configurations and characteristics of different innovations was summarized. Then, overall treatment performance of those systems and their shortcomings were further discussed. Lastly, future perspectives were also identified for specialists to design more effective and sustainable CWs. This information is used to inspire some novel intensifying methodologies, and benefit the successful applications of potential CW technologies.

Fertilization is important to increase crop yields, but long-term application of fertilizers probably aggravated the risk of heavy metals in acidic soils. In this study, the effect of 22-year fertilization and cropping on accumulation, availability, and uptake of heavy metals in red soil was investigated. The results showed that pig manure promoted significantly cadmium (Cd) accumulation (average 1.1 mg kg⁻¹), nearly three times higher than national soil standards and, thus, increased metal availability. But the enrichment of heavy metals decreased remarkably by 50.5 % under manure fertilization, compared with CK (control without fertilization). On the contrary, chemical fertilizers increased greatly lead (Pb) availability and Cd activity; in particular, exceeding 85 % of soil Cd became available to plant under N (nitrogen) treatment during 9–16 years of fertilization, which correspondingly increased their enrichment by 29.5 %. Long-term application of chemical fertilizers caused soil acidification and manure fertilization led to the increase in soil pH, soil organic matter (SOM), and available phosphorus (Olsen P), which influenced strongly metal behavior in red soil, and their effect had extended to deeper soil layer (20∼40 cm). It is advisable to increase application of manure alone with low content of heavy metals or in combination with chemical fertilizers to acidic soils in order to reduce toxic metal risk.

The paper presents the kinetics and proposed pathways photodegradation and photooxidation of p-arsanilic acid, in a neutral environment by ozone and hydrogen peroxide. The results showed that in a neutral environment, photoozonation process was characterized by the highest decomposition rate constant (k) (k = 31.8 × 10⁻³ min⁻¹). The rate constants decreased in the order UV/O₃ > O₃ > UV/H₂O₂ > H₂O₂ > UV. It was also found that under pH = 7, decomposition of p-arsanilic acid leads mainly to the formation of aniline, which undergoes secondary reactions. Intermediate products of oxidation and photooxidation by hydrogen peroxide like nitrobenzene, nitrophenol, azobenzenes, and phenylazophenol were identified depending on processes. However, in the photodegradation process, formation of nitrasone as a reaction product of p-arsanilic acid with oxygen in the singlet state was observed. In the case of ozonation and photoozonation, in addition, aniline formation of carboxylic acids was observed.

In this study, the removal efficiency of 136 tetra- to octa-chlorinated dibenzo-p-dioxin (CDD)/furan (F) congeners from a nitrogen + oxygen carrier gas was studied using a laboratory-scale, fixed bed adsorption system. Two kinds of activated carbon with dissimilar pore structures were used as adsorbents. The total concentration of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in the source gas was 541 ng/Nm³ and that of the 17 toxic 2,3,7,8-substituted PCDD/Fs 96.35 ng/Nm³, accounting for 17.8 % of the total original weight amount. Their toxic equivalent quantity (TEQ) was 8.31 ng I-TEQ/Nm³. For both activated carbons, the removal efficiencies of the ten PCDD/F homologue groups rise with chlorine substitution number. The removal efficiencies vary approximately as a power function of vapor pressure (correlation coefficients r ² = 0.93 and 0.81, respectively). Competitive adsorption and desorption occur as adsorption time went on, causing elution of the lower chlorinated homologues, i.e. tetra-CDD/F and Penta-CDD/F congeners. In addition, there are significantly different concentration distributions for isomers in the same homologue groups. However, their removal efficiencies have weak correlation with their initial concentrations. The correlation coefficients are from −0.47 to 0.32 and from −0.57 to 0.46 respectively for the two kinds of activated carbons.

The objectives of this work are to track the contamination levels, distribution characteristics, and sources of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in atmospheric particulate matter (APM) of Northern China and to provide more comprehensive and fundamental data for risk assessment of organochlorine contaminants (OCs) in environments. Samples were extracted and purified by the microwave-assisted extraction and solid-phase extraction system, respectively. PCBs and OCPs were analyzed by gas chromatograph-mass spectrometer. The concentrations of ΣPCBs and ΣOCPs ranged from 0.73 to 112.65 ng/g and 0.14 to 34.73 ng/g, respectively. PCBs in atmospheric particulates collected from Shijiazhuang City had the highest concentration, whereas OCP congeners were at the relatively low levels. However, the highest concentration of OCPs occurred in Yongning City. The principal component analysis indicated that the predominant compositions of PCBs in most of samples were tetrachlorobiphenyl (Tetra-CB), pentachlorobiphenyl (Penta-CB), hexachlorobiphenyl (Hexa-CB), and heptachlorbiphenyl (Hepta-CB), while hexachlorocyclohexanes (HCHs), DDTs, chlordanes, and endosulfans were the dominant components of OCPs, which was attributed to their application characteristics. OCs in those particles were further used to assess a potential cancer risk to humans via ingestion, dermal contact, and inhalation. Cancer risk was evaluated in airborne particles caused by PCBs and OCPs. TEQPCBₛ values suggested that the representative areas were subject to different pollution degrees. However, the pollution of OCPs in certain areas should be a concern due to 41.6 % of the high risk, which could pose a potential risk to organisms.

Transcriptomics is often used to investigate changes in an organism’s genetic response to environmental contamination. Data noise can mask the effects of contaminants making it difficult to detect responding genes. Because the number of genes which are found differentially expressed in transcriptome data is often very large, algorithms are needed to reduce the number down to a few robust discriminative genes. We present an algorithm for aggregated analysis of transcriptome data which uses multiple fold-change thresholds (threshold screening) and p values from Bayesian generalized linear model in order to assess the robustness of a gene as a potential indicator for the treatments tested. The algorithm provides a robustness indicator (ROBI) as well as a significance profile, which can be used to assess the statistical significance of a given gene for different fold-change thresholds. Using ROBI, eight discriminative genes were identified from an exemplary dataset (Danio rerio FET treated with chlorpyrifos, methylmercury, and PCB) which could be potential indicators for a given substance. Significance profiles uncovered genetic effects and revealed appropriate fold-change thresholds for single genes or gene clusters. Fold-change threshold screening is a powerful tool for dimensionality reduction and feature selection in transcriptome data, as it effectively reduces the number of detected genes suitable for environmental monitoring. In addition, it is able to unmask patterns in altered genetic expression hidden by data noise and reduces the chance of type II errors, e.g., in environmental screening.

Opuntia ficus-indica (Ofi) is a long-domesticated cactus that is widespread throughout arid and semiarid regions. Ofi is grown for both its fruits and edible cladodes, which are flattened photosynthetic stems. Young cladodes develop from mother cladodes, thus forming series of cladodes of different ages. Therefore, successive cladodes may hold some potential for biomonitoring over several years the local atmospheric pollution. In this study, cladodes, roots, dust deposited onto the cladodes, and soil samples were collected in the vicinity of three heavily polluted sites, i.e., a fertilizer industry, the road side of a highway, and mine tailings. The lead content was analyzed using atomic absorption spectroscopy (AAS) and inductively coupled plasma-mass spectrometry (ICP-MS). Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) was used to characterize the cladode surfaces and the nature of dust deposit, and the lead isotopes were analyzed to identify the origin of Pb. The results show that (i) Ofi readily bioaccumulates Pb, (ii) the lead isotopic composition of cladodes evidences a foliar pathway of lead into Ofi and identifies the relative contributions of local Pb sources, and (iii) an evolution of air quality is recorded with successive cladodes, which makes Ofi a potential biomonitor to be used in environmental and health studies.

Sediments in confluence areas are typically contaminated by various pollutants that have been transported there by inflowing rivers. In this study, we evaluated the pollution status of a confluence area in Lake Chaohu (China). Both the nutrients and hazardous pollutants were analysed. Most sediment cores showed large variations in nutrient concentrations at depths of 10 to 18 cm. Positive release rates of NH₄ ⁺-N and PO₄ ³⁻-P were detected in sediment cores. Hg and Cd were the most typical problematic metal contaminants encountered, and their contamination levels extended to depths of 20 and 25 cm, respectively. Polycyclic aromatic hydrocarbons (mostly acenaphthene and fluorine) were the primary persistent organic pollutants (POPs) present in sediments, and contamination levels frequently could be detected up to a depth of 16 cm. Simulated dredging operations were implemented in the laboratory, with a dredging depth of 15 cm found to be suitable for nutrient suppression. With the goal of suppressing nutrients release and removing high-risk metals and POPs, a multi-objective dredging plan was developed. This plan subdivides the confluence area into five parts that were treated with different dredging depths. A demonstration area was dredged in the most heavily polluted part, and the observed dredging effects were consistent with those expected on the basis of the plan. Such an approach to dredging might also be useful in other areas in the future.

Temporal variation of airborne particulate mass concentration was measured in terms of toxic organics, metals and water-soluble ionic components to identify compositional variation of particulates in Varanasi. Information-related fine particulate mass loading and its compositional variation in middle Indo-Gangetic plain were unique and pioneering as no such scientific literature was available. One-year ground monitoring data was further compared to Moderate Resolution Imaging Spectroradiometer (MODIS) Level 3 retrieved aerosol optical depth (AOD) to identify trends in seasonal variation. Observed AOD exhibits spatiotemporal heterogeneity during the entire monitoring period reflecting monsoonal low and summer and winter high. Ground-level particulate mass loading was measured, and annual mean concentration of PM₂.₅(100.0 ± 29.6 μg/m³) and PM₁₀(176.1 ± 85.0 μg/m³) was found to exceed the annual permissible limit (PM₁₀: 80 %; PM₂.₅: 84 %) and pose a risk of developing cardiovascular and respiratory diseases. Average PM₂.₅/PM₁₀ratio of 0.59 ± 0.18 also indicates contribution of finer particulates to major variability of PM₁₀. Particulate sample was further processed for trace metals, viz. Ca, Fe, Zn, Cu, Pb, Co, Mn, Ni, Cr, Na, K and Cd. Metals originated mostly from soil/earth crust, road dust and re-suspended dust, viz. Ca, Fe, Na and Mg were found to constitute major fractions of particulates (PM₂.₅: 4.6 %; PM₁₀: 9.7 %). Water-soluble ionic constituents accounted for approximately 27 % (PM₁₀: 26.9 %; PM₂.₅: 27.5 %) of the particulate mass loading, while sulphate (8.0–9.5 %) was found as most dominant species followed by ammonium (6.0–8.2 %) and nitrate (5.5–7.0 %). The concentration of toxic organics representing both aliphatic and aromatic organics was determined by organic solvent extraction process. Annual mean toxic organic concentration was found to be 27.5 ± 12.3 μg/m³(n = 104) which constitutes significant proportion of (PM₂.₅, 17–19 %; PM₁₀, 11–20 %) particulate mass loading with certain exceptions up to 50 %. Conclusively, compositional variation of both PM₂.₅and PM₁₀was compared to understand association of specific sources with different fractions of particulates.