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.

The total concentrations of 12 heavy metals in surface soils (SS, 0–20 cm), middle soils (MS, 30–50 cm) and deep soils (DS, 60–80 cm) from an acid-leaching area, a deserted paddy field and a deserted area of Guiyu were measured. The results showed that the acid-leaching area was heavily contaminated with heavy metals, especially in SS. The mean concentrations of Ni, Cu, Zn, Cd, Sn, Sb and Pb in SS from the acid-leaching area were 278.4, 684.1, 572.8, 1.36, 3,472, 1,706 and 222.8 mg/kg, respectively. Heavy metal pollution in the deserted paddy field was mainly concentrated in SS and MS. The average values of Sb in SS and MS from the deserted paddy field were 16.3 and 20.2 mg/kg, respectively. However, heavy metal contamination of the deserted area was principally found in the DS. Extremely high concentrations of heavy metals were also observed at some special research sites, further confirming that the level of heavy metal pollution was very serious. The geoaccumulation index (Igₑₒ) values revealed that the acid-leaching area was severely polluted with heavy metals in the order of Sb > Sn > Cu > Cd > Ni > Zn > Pb, while deserted paddy field was contaminated predominately by metals in the order of Sb > Sn > Cu. It was obvious that the concentrations of some uncommon contaminants, such as Sb and Sn, were higher than principal contaminants, such as Ni, Cu, Zn and Pb, suggesting that particular attention should be directed to Sn and Sb contamination in the future research of heavy metals in soils from e-waste-processing areas. Correlation analysis suggested that Li and Be in soils from the acid-leaching area and its surrounding environment might have originated from other industrial activities and from batteries, whereas Ni, Cu, Zn, Cd, Pb, Sn and Sb contamination was most likely caused by uncontrolled electronic waste (e-waste) processing. These results indicate the significant need for optimisation of e-waste-dismantling technologies and remediation of polluted soil environment.

Copper (Cu) is an essential micronutrient for normal plant growth and development, but in excess, it is also toxic to plants. The present study investigated the influence of ethylenediaminetetraacetic acid (EDTA) in enhancing Cu uptake and tolerance as well as the morphological and physiological responses of Brassica napus L. seedlings under Cu stress. Four-week-old seedlings were transferred to hydroponics containing Hoagland’s nutrient solution. After 2 weeks of transplanting, three levels (0, 50, and 100 μM) of Cu were applied with or without application of 2.5 mM EDTA and plants were further grown for 8 weeks in culture media. Results showed that Cu alone significantly decreased plant growth, biomass, photosynthetic pigments, and gas exchange characteristics. Cu stress also reduced the activities of antioxidants, such as superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein contents. Cu toxicity increased the concentration of reactive oxygen species (ROS) as indicated by the increased production of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) in both leaves and roots. The application of EDTA significantly alleviated Cu-induced toxic effects in B. napus, showing remarkable improvement in all these parameters. EDTA amendment increased the activity of antioxidant enzymes by decreasing the concentrations of MDA and H₂O₂both in leaves and roots of B. napus. Although, EDTA amendment with Cu significantly increased Cu uptake in roots, stems, and leaves in decreasing order of concentration but increased the growth, photosynthetic parameters, and antioxidant enzymes. These results showed that the application of EDTA can be a useful strategy for phytoextraction of Cu by B. napus from contaminated soils.

To determine potential surrogates of biofilm-dwelling ciliate fauna for assessing water quality, a dataset of coastal waters of the Yellow Sea was studied. Samples were collected monthly at a depth of 1 m from four sampling stations during a 1-year cycle (August 2011–July 2012), northern China. The ciliate communities at low taxonomic resolutions up to family level were significantly correlated with the full ciliate fauna at species-level resolution and represented a significant spatial variation in relation to the environmental changes. The presence/absence resolutions up to genus level maintained sufficient information of the ciliate species-abundance matrix. The vagile and sessile ciliate assemblages were significantly correlated with the full ciliate communities but only the latter maintained sufficient information with a significant spatial variation in response to the environmental stress. Correlation analyses showed that the taxon richness indices of potential surrogates at genus- and family-level resolutions can explain >95 % of the variance in that of the full species pool. Thus, it is suggested that the taxonomic resolutions up to family level may be a robust time-efficient surrogate of whole periphytic ciliate communities for assessing water quality status and would allow improving sampling strategies of large spatial scale monitoring programs, using biofilm-dwelling ciliates, in coastal waters.

The main aim of this study was to determine the sorption and biodegradation parameters of trichloroethene (TCE) and tetrachloroethene (PCE) as input data required for their fate and transport modelling in a Quaternary sandy aquifer. Sorption was determined based on batch and column experiments, while biodegradation was investigated using the compound-specific isotope analysis (CSIA). The aquifer materials medium (soil 1) to fine (soil 2) sands and groundwater samples came from the representative profile of the contaminated site (south-east Poland). The sorption isotherms were approximately linear (TCE, soil 1, K d = 0.0016; PCE, soil 1, K d = 0.0051; PCE, soil 2, K d = 0.0069) except for one case in which the best fitting was for the Langmuir isotherm (TCE, soil 2, K f = 0.6493 and S ₘₐₓ = 0.0145). The results indicate low retardation coefficients (R) of TCE and PCE; however, somewhat lower values were obtained in batch compared to column experiments. In the column experiments with the presence of both contaminants, TCE influenced sorption of PCE, so that the R values for both compounds were almost two times higher. Non-significant differences in isotope compositions of TCE and PCE measured in the observation points (δ¹³C values within the range of −23.6 ÷ −24.3 ‰ and −26.3 ÷−27.7 ‰, respectively) indicate that biodegradation apparently is not an important process contributing to the natural attenuation of these contaminants in the studied sandy aquifer.

Surface soil samples were collected from urban agglomeration of the Yangtze River Delta (YRD), China in 2003 and 2012, respectively. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were analyzed to determine if there were any changes in their levels and compositional profiles between the two sampling years. The concentrations of Σ₈PBDEs ranged from 0.553 to 13.0 μg kg⁻¹(with the mean of 3.31 μg kg⁻¹) in the 2003 samples and from 1.01 to 43.2 μg/kg (with the mean of 10.0 μg kg⁻¹) in the 2012 samples. The concentrations of Σ₃₂PCBs ranged from 0.301 to 3.29 μg kg⁻¹(with the mean of 1.01 μg kg⁻¹) in the 2003 samples and from 0.205 to 3.96 μg/kg (with the mean of 0.991 μg kg⁻¹) in the 2012 samples. The comparisons between the 2012 and 2003 data showed that PBDEs concentrations increased over the years, but PCB concentrations did not change much. BDE-209 was the major BDE congener in both the 2003 and 2012 samples, indicating that the dominant PBDE mixture production and usage in the YRD had been the commercial deca-BDE mixture. Investigation of the PBDE congener profiles indicated that there had been new input of octa-BDEs in this region in recent years. Little change was found for the pattern of PCBs congener profiles between 2 years’ samples. As such, spatial distributions of PBDEs or PCBs in surface soil samples reflected a gradient (from high to low) from the central cities out to rural areas in both the 2003 and 2012 data. In addition, high concentrations of PBDEs were observed in the industrial and residential areas, whereas high concentrations of PCBs were only observed in the industrial areas.

The European earwig Forficula auricularia is an effective predator in apple orchards. It is therefore crucial to study whether insecticides affect this natural pest control agent. Predation activity, i.e., the number of aphids eaten in 24 h, was determined under laboratory conditions after exposure of fourth-instar nymphs and adult earwigs to widely used insecticides (acetamiprid, chlorpyrifos-ethyl, deltamethrin, and spinosad), which were applied at the normal application rates. Inhibition of acetylcholinesterase and carboxylesterase activities were also measured as indicators of pesticide exposure. Predation activity decreased significantly in nymphs exposed to spinosad (62 %) and chlorpyrifos-ethyl (98 %) compared with controls. A similar response was found for both esterase activities. Spinosad had a stronger effect on AChE (−33 %) whereas chlorpyrifos-ethyl affected CbE activity preferentially (−59 %). Spinosad (20 % of controls), acetamiprid (28 %), and chlorpyrifos-ethyl (66 %) also significantly decreased the predation behavior of adult male but not female (5 to 40 %) earwigs. Adult AChE and CbE activities were also significantly reduced (28 to 67 % of controls) in pesticide-exposed earwigs. Our results suggest that earwigs should be included in the environmental risk assessment framework for authorization of newly marketed plant protection products. Their predation behavior appears to be a sensitive and complementary biomarker.

Separation and reuse of dispersed nanoparticles are major obstacles to the extensive application of nano-sized absorbents in wastewater treatment. Herein, we demonstrate the capability of directing acid-oxidized carbon nanotubes (CNTs) as the transfer vehicles of heavy metal ions from simulated wastewater. The heavy metal-loaded CNTs can be readily separated from the aqueous phase via the aggregation process at an oil/water (o/w) interface. The minimum surfactant amount to achieve 99 % transfer ratio (T ᵣ) of 100 mg/L CNTs from water phase to o/w interface was ∼0.01 mM. The adsorption experiments showed that the removal efficiency of the divalent lead ions increased with an increase in CNT mass, and the subsequent addition of cetyltrimethylammonium bromide (CTAB) surfactant did not negatively impact the removal of soluble divalent lead species (Pb(II)). In a wide region of pH and ionic strength, both the decontamination of Pb(II) and the transfer of CNTs from water phase to o/w interface can be accomplished successively. The method presented in this study may be developed as a generic one for collecting or recycling the pollutant-loaded nano-sized absorbents.