Cerium (Ce, CeCl₃) and Erbium (Er, ErCl₃) are increasingly used in many electronic devices facilitating the alteration of their biogeochemical cycles (e.g. e-waste). Previous surveys stated that their environmental concentrations due to natural or anthropogenic events can reach up to 161 μg/L in ore mine effluent for Ce with a mean water concentration of 0.79 μg/L, and 11.9 μg/L for Er in ore mine effluents with a mean water concentration of 0.004 μg/L. Their potential effects onto aquatic organisms are still relatively unexplored. In this study, long-term multigenerational effects on Daphnia magna were assessed using various exposure times (3, 7, 14, and 21 days) in three generations (F0, F1 and F2). Each generation was exposed to environmental concentrations of Ce and Er (0.54 and 0.43 μg/L, respectively – mean values) and effects included organisms' size, parental reproduction, and survival, determination of reactive oxygen species (ROS), enzymatic activity (superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST)), gene expression of ATP-binding cassette (ABC) transporter, and uptake.Results evidenced that chronic multi-generational exposure of daphnids to Ce and Er reduced survival, growth and reproduction, decreasing ROS, SOD and CAT from F0 to F2. Ce reduced the number of generated offsprings after each generation, while Er delayed the time of offsprings emergence, but not their number. ROS, SOD, CAT and GST evidenced that Er is slightly more toxic than Ce. Up- and downregulation of genes was limited, but Ce and Er activated the ABC transporters. Uptake of Ce and Er decreased through exposure time and generations.

Transformation of organic microcontaminants (OMCs) during wastewater treatments results in the generation of transformation products (TPs), which can be more persistent than parent compounds. Due to reuse of reclaimed wastewater (RWW) for crop irrigation, OMCs and TPs are released in soils being capable to translocate to crops. Furthermore, OMCs are also susceptible to transformation once they reach the soil or crops. The recalcitrant antiepileptic carbamazepine (CBZ) and some of its frequently reported TPs have been found in agricultural systems. However, there is no knowledge about the fate in reuse practices of multiple CBZ TPs that can be formed during wastewater treatment processes. For the first time, this work presents a study of the behavior of CBZ TPs generated after a conventional Ultraviolet-C (UVC) treatment in an agricultural environment. The UVC-treated water was used for the irrigation of lettuces grown under controlled conditions. The latter was compared to the fate of TPs generated in the peat and plant by irrigation with non-treated water containing CBZ. A suspect screening strategy was developed to identify the TPs using liquid chromatography coupled to quadrupole-time-of-flight (LC-QTOF-MS). The results revealed the presence of 24 TPs, 22 in UVC-treated water, 11 in peat and 9 in lettuce leaves. 4 of the TPs identified in peat (iminostilbene, TP 271B, TP 285A-B); and 3 in leaves (10–11 dihydrocarbamazepine, TP 271A-B) were not previously reported in soils or edible parts of crops, respectively. Comparing the TPs found in peat and lettuces derived from both irrigation conditions, no significant differences regarding TPs formation or occurrence were observed. UVC treatment did not contribute to the formation of different TPs than those generated by transformation or metabolism of CBZ in peat or plant material. This research improves the current knowledge on the fate of CBZ TPs in agricultural systems because of reuse practices.

Multi-walled carbon nanotubes (MWCNTs) are increasing used in commercial applications and may be released into the environment with anionic surfactants, such as sodium dodecylbenzenesulfonate (SDBS), in sewer discharge. Little research has examined the transport, retention, and remobilization of MWCNTs in the presence or absence of SDBS in porous media with controlled chemical heterogeneity, and batch and column scale studies were therefore undertaken to address this gap in knowledge. The adsorption isotherms of SDBS on quartz sand (QS), goethite coated quartz sand (GQS), and MWCNTs were determined. Adsorption of SDBS (MWCNTs » GQS > QS) decreased zeta potentials for these materials, and produced a charge reversal for goethite. Transport of MWCNTs (5 mg L⁻¹) dramatically decreased with an increase in the fraction of GQS from 0 to 0.1 in the absence of SDBS. Conversely, co-injection of SDBS (10 and 50 mg L⁻¹) and MWCNTs radically increased the transport of MWCNTs when the GQS fraction was 0, 0.1, and 0.3, especially at a higher SDBS concentration, and altered the shape of retention profile. Mathematical modeling revealed that competitive blocking was not the dominant mechanism for the SDBS enhancement of MWCNT transport. Rather, SDBS sorption increased MWCNT transport by increasing electrostatic and/or steric interactions, or creating reversible interactions on rough surfaces. Sequential injection of pulses of MWCNTs and SDBS in sand (0.1 GQS fraction) indicated that SDBS could mobilize some of retained MWCNTs from the top to deeper sand layers, but only a small amount of released MWCNTs were recovered in the effluent. SDBS therefore had a much smaller influence on MWCNT transport in sequential injection than in co-injection, presumably because of a greater energy barrier to MWCNT release than retention. This research sheds novel insight on the roles of competitive blocking, chemical heterogeneity and nanoscale roughness, and injection sequence on MWCNT retention and release.

Although amino modified nanopolystyrene could cause toxicity on environmental organisms, the effect of amino modification on nanopolystyrene toxicity is still largely unclear. We here employed Caenorhabditis elegans as an animal model to compare the effects between pristine and amino modified nanopolystyrene particles in inducing reproductive toxicity. Nanopolystyrene (35 nm) could cause the damage on gonad development as indicated by the endpoints of number of total germline cells, length of gonad arm, and relative area of gonad arm. Nanopolystyrene exposure also reduced the reproductive capacity as reflected by the endpoints of brood size and number of fertilized eggs in uterus. Moreover, amino modification enhanced nanopolystyrene toxicity on both the gonad development and the reproductive capacity. Additionally, induction of germline apoptosis and formation of germline DNA damage contributed to the enhancement of nanopolystyrene toxicity in reducing reproductive capacity by amino modification. Our results highlight the potential environmental risk of amino modified nanopolystyrene in inducing reproductive toxicity on gonad development and reproductive capacity of environmental organisms.

Heavy metal data measured by portable X-ray fluorescence (PXRF), especially by in-situ PXRF, are usually affected by multiple soil factors, such as soil moisture (SM), soil organic matter (SOM), and soil particle size (SPZ). Thus, a correction may be needed. However, traditionally-used correction methods, such as non-spatial linear regression (LR), cannot effectively correct the spatially non-stationary influences of the related soil factors on PXRF analysis. Moreover, these correction methods are not robust to outliers. In this study, robust geographically weighted regression (RGWR) was used to correct in-situ and ex-situ PXRF data of soil Pb in a peri-urban agricultural area of Wuhan City, China. The accuracy of the corrected PXRF data by RGWR was compared with those by non-spatial and spatial but non-robust methods (i.e., LR and GWR). In addition, to find an appropriate method of using the corrected PXRF data for more accurate spatial prediction, we compared robust ordinary kriging with the corrected PXRF data as part of hard data (ROK-CPXRF) and robust ordinary cokriging with the corrected PXRF data as auxiliary soft data (RCoK-CPXRF). Results showed that (i) RGWR obtained higher correction accuracy than LR and GWR on both the in-situ and ex-situ PXRF data; (ii) the accuracy of the RGWR-corrected in-situ PXRF data was increased nearly to that of the RGWR-corrected ex-situ PXRF data; (iii) given the same amount of sample data, ROK-CPXRF obtained higher prediction accuracy than RCoK-CPXRF. It is concluded that the methods suggested in this study may largely promote the application of in-situ PXRF technique for rapid and accurate soil heavy metal investigation in large-scale areas.

Cu, Mn, Fe, Zn, Cd and Pb levels were measured in liver and muscle samples of Rainbow Trout Oncorhynchus mykiss collected from three watersheds with different land-uses: native forest, exotic plantation, and agriculture in Chile, during January, April, July, and October 2012. Cd and Pb levels were not detected in the liver and muscle, probably since they are under the detection limits. Higher metal concentrations (liver-muscle tissues) were detected in samples from agriculture and exotic plantation streams, whereas trout from native forest streams had lower metal concentrations. Higher metal concentrations were detected in liver tissue compared to muscle tissue, and both negatively correlated to the length and weight of the fish. This suggest the liver had higher ability to accumulate Cu, Mn, Fe and Zn compared to muscle tissue. The concentration range of Fe and Zn recorded in the muscle are within the range reported by other authors, whereas Mn and Cu concentrations are higher than reported in the literature. However, at all sites the concentration of selected metals were below the limits permitted by current legislation (FAO), and therefore did not put the human population at risk, suggesting that is eating wild rainbow trout safe in Chile.

The high concentration of fluoride (F) in soils has become a rising concern for its toxicity to microbes, plants, animals and human health. In the present study, the spatial and vertical distribution, health risk assessment and anthropogenic sources of F in farmland soils in an industrial area dominated by phosphate chemical plants were studied. Concentrations of total fluoride (TF) and water soluble fluoride (WSF) in the surface soils decreased with distance within the range of 2500 m at the prevailing downwind of the industrial area. The soil TF and WSF concentrations in 0–40 cm profiles were higher than those in 40–100 cm layers in the industrial area. At the prevailing downwind of the industrial area within 700 m, the hazard quotient values of human exposure to surface soils were higher than 1, indicating that a potential risk may exist for human health in this area. The main exposure pathway for children and adults was oral ingestion and particulate inhalation, respectively. The source apportionment model of soil F was modified based on years’ historical data and experimental data. The results showed that the proportion of anthropogenic sources of soil F was dustfalls (69%) > irrigation water (23%) > air (5%) > chemical fertilizers (3%) in the industrial area. The high F concentration of dustfalls was mainly due to the phosphate rock, phosphogypsum, and surface soils with high F contents from the factories. In order to safeguard human health and alleviate hazards of F to surroundings, the control of pollutants emission from factories was a basic and vital step to reduce F in the soils in industrial areas.

The study was aimed to evaluate the ability of native lichen Xanthoria (X.) parietina to biomonitor and bioaccumulate some heavy metals (As, Cd, Co, Cr, Ni, Pb), PAHs, PCDDs, PCDFs, PCBs and PBDEs and to evaluate the use of the native X. parietina as a multi-tracer tool for scenarios characterized by different anthropogenic pressures. Samples of native X. parietina were collected in six different sites (two green, two residential and two industrial areas, respectively) and analyzed for the target compounds.The results show that X. parietina was a useful tool for the biomonitoring of air quality in the selected areas, and was able to bioaccumulate all the studied metals and POPs. In particular, the total concentrations dry weight (dw) ranged between 8.1 and 103.4 mg kg⁻¹ for metals, from 113 × 10³ to 183 × 10³ ng kg⁻¹ for PAHs, from 868 to 7685 ng kg⁻¹ for PCBs, from 14.3 to 113.8 ng kg⁻¹ for PCDDs/Fs (∑TEq = 0.9–7.1), and from 194 to 554 ng kg⁻¹ for PBDEs.Besides, in general, the levels of analytes recovered in the different samples of lichen show an increasing trend from green to industrial sites, especially for PCBs (mean values equal to 1218, 4253 and 7192 ng kg⁻¹ respectively for green, residential and industrial areas).The statistical approach, based on Pearson's correlation and principal component analysis tests, showed that one of the industrial sites was well-separated from the others, that resulted grouped due to some similarities.

In the present investigation seaweeds of macroalgae like Kappaphycus alvarezii, Gracilaria salicornia and Gracilaria edulis used as novel biosorbent in native (KA, GS, GE) and ethanol modified (EKA, EGS, EGE) for Rhodamine B (RB) removal from aqueous solution in batch process. Effect of various biosorption parameters such as pH, initial concentration of RB, biosorbent dosage and contact time were studied. The maximum biosorption capacity determined as 9.84 (KA), 11.03 (GS), 8.96 (GE), 112.35 (EKA), 105.26 (EGS) and 97.08 mg/g (EGE), respectively towards the removal of RB from aqueous solutions. Better removal of RB was observed using EKA, EGS, and EGE biosorbents at 2.0 pH. The characterizations of the biosorbents were performed using Scanning Electron microscope and Fourier Transform Infrared Spectroscopy. Biosorption equilibrium data evaluated using Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Jovanovic isotherm model. The Langmuir isotherm model best suited the equilibrium data for all the biosorbents studied. The rate of RB removal subjected to kinetic analysis using pseudo-first-order, pseudo-second-order, intra-particle diffusion and Elovich models. Pseudo-second-order kinetic model better described the experimental data of the RB biosorption. Desorption studies performed using 0.1 M sodium hydroxide as eluting agents for regeneration and recycle analysis. The recyclability of the six biosorbents showed consistent biosorption capacity towards RB removal up to the entire three cycles. The studied biosorbents sourced from large volume and easily available, further biosorption performance indicated that the KA, GS, GE, EKA, EGS and EGE could be used as efficient, alternative and eco-friendly biosorbents for the removal of harmful dyes in the environment.

Understanding the mercury (Hg) methylation process is important for the management of paddy soils contaminated by Hg. In this work, samples of eighteen paddy soils with varying soil properties were spiked with inorganic Hg and subjected to a 90 d flooding period. Soil pH and redox potential (Eh) were measured in situ at intervals, and soils were sampled for the analysis of methylmercury (MeHg). The Hg methylation efficiency increased with flooding time and reached a relatively steady state at 30 d of incubation, ranging from 0.08% to 2.52%, and was significantly correlated with the in situ soil pH and Eh. The Elovich equation could adequately describe the kinetic production of MeHg. MeHg production was well predicted by the in situ soil pH and Eh of flooded soils, in addition to the organic matter content of air-dried soil samples and flooding time. The two predictive models explained 78% and 68% of the variability of the Hg methylation efficiency. The results suggested that the methylation of inorganic Hg in paddy soils after flooding can be predicted as a function of routinely measured soil properties and flooding time, a correlation that can be utilized to improve understanding of the extent of Hg methylation and the management of Hg-contaminated paddy soils.