In the present study, we evaluate our previously developed non-destructive soil algal toxicity method using species from a different class of algae; Class Trebouxiophyceae (Chlorella vulgaris and Chlorella sorokiniana), and directly measure the photosynthetic activity of these species adsorbed onto the soil as a new toxicity endpoint. This study shows that non-destructive soil algal toxicity method is applicable to non-specific test species, including those of Class Trebouxiophyceae as well as Class Chlorophyceae (Chlorococcum infusionum and Chlamydomonas reinhardtii). Furthermore, by performing photosynthesis image analysis, we verify that it is possible to measure the photosynthetic activity of soil algae Chlorella vulgaris adsorbed onto soils without the need to extract algal cells from the soil. We propose that the non-destructive soil algal toxicity method represents a novel technique for 1) evaluating pollutants in soil using non-specific algae and 2) conveniently and rapidly assessing the photosynthetic activity of soil algae Chlorella vulgaris adsorbed onto soil as a new toxicity endpoint.

This study aimed to evaluate and qualify field-based potential risks of seven neonicotinoid and phenylpyrazole (fipronil) insecticides on aquatic invertebrates, including estuary-resident marine crustaceans. One hundred and ninety-three estuarine water samples, with salinity ranging from 0.5 to 32.7, were collected from four estuarine sites in the Seto Inland Sea of Japan, in 2015–2018 and the insecticide levels were measured. Five neonicotinoid and fipronil insecticides were successfully identified, and their occurrence varied temporally. Marine crustaceans were simultaneously harvested every month from one of the estuarine water sampling sites in 2015–2017. Three predominant crustacean species, kuruma prawn (Penaeus japonicus), sand shrimp (Crangon uritai), and mysid (Neomysis awatschensis), were captured and their seasonal presence was species independent. A 96-h laboratory toxicity study with the insecticides using kuruma prawn, sand shrimp, and a surrogate mysid species (Americamysis bahia) indicated that fipronil exerted the highest toxicity to the three crustaceans. Using both toxicity data and insecticide occurrence in estuarine water (salinity ≥10, n = 169), the potential risks on the three marine crustaceans were quantified by calculating the proportion of mixture toxicity effects (Pₘᵢₓ). The Pₘᵢₓ of seven neonicotinoids on the crustaceans was less than 0.8%, which is likely to be too low to indicate adverse effects caused by the insecticides. However, short temporal detection of fipronil (exclusively in June and July) significantly affected the Pₘᵢₓ, which presented the maximal Pₘᵢₓ values of 21%, 3.4%, and 72% for kuruma prawn, sand shrimp, and mysid, respectively, indicating a significant effect on the organisms. As for estuarine water (salinity <10), some water samples contained imidacloprid and fipronil exceeding the freshwater benchmarks for aquatic invertebrates. The present study provides novel insights into the seasonally varying risks of insecticides to estuarine crustaceans and highlights the importance of considering whether ecological risk periods coincide with crustacean presence.

Aryl phosphorus-containing flame retardants (aryl-PFRs) have been frequently detected with increasingly used worldwide as one of alternatives for brominated flame retardants. However, information on their adverse effects on human health and ecosystem is insufficient, with limited study on their molecular mode of action in vitro. In this study, the cytotoxicity, DNA damage, mitochondrial impairment and the involved molecular mechanisms of certain frequently detectable aryl-PFRs, including 2-ethylhexyldiphenyl phosphate (EHDPP), methyl diphenyl phosphate (MDPP), bisphenol-A bis (diphenyl phosphate) (BDP), isodecyl diphenyl phosphate (IDPP), cresyl diphenyl phosphate (CDP) and the structurally similar and widely used organophosphorus pesticide chlorpyrifos (CPF), were evaluated in A549 cells using high-content screening (HCS) system. Aryl-PFRs showed different lethal concentration 50 (LC50) values ranging from 97.94 to 546.85 μM in A549 cells using CCK-8 assay. EHDPP, IDPP, CDP, MDPP and CPF demonstrated an ability to induce DNA damage, evidenced by increased DNA content and S phase-reducing cell cycle arrest effect using fluorophore dye cocktail assay. Additionally, the selected aryl-PFRs induced mitochondrial impairment by the increasing mitochondrial mass and decreasing mitochondrial membrane potential. Moreover, BDP, MDPP, and CDP, which contain short alkyl chains showed their potential oxidative stress with intracellular ROS and mitochondrial superoxide overproduction from an initially relatively low concentration. Additionally, based on the promotion of firefly luminescence in p53-transfected A549 cells, p53 activation was found to be involved in aryl-PFRs-induced DNA damage. Further real-time PCR results showed that all selected aryl-PFRs triggered p53/p21/gadd45β-, and p53/p21/mdm2-mediated cell cycle pathways, and the p53/bax mediated apoptosis pathway to induce DNA damage and cytotoxic effects. These results suggest that aryl-PFRs (e.g., BDP, MDPP, CDP) cause oxidative stress-mediated DNA damage and mitochondrial impairment, and p53-dependent pathway was involved in the aryl-PFRs-induced DNA damage and cell cycle arrest. In conclusion, this study improves the understanding of PFRs-induced adverse outcomes and the involved molecular mechanism.

Water diversion projects have been continuously used to alleviate water quality issues that arise during urbanization. However, studies about whether it has possible effects on the status of pharmaceutical and personal care products (PPCPs) are limited. In this study, the occurrence trends and spatial-temporal distribution characteristics of 50 PPCPs were investigated in surface water, suspended particulate matter (SPM) and sediments in Nanjing urban rivers under the background of the water diversion project from the Yangtze River to the Qinhuai River. In the four field campaigns that were embarked on April to July 2018, a total of 40, 38 and 24 PPCPs were detected in surface water, SPM and sediments, respectively, with overall concentrations of 138–1990 ng/L, 3214–33701 ng/g and 12.1–109 ng/g dry weight (dw) among nine sampling sites. The excessive concentration of caffeine (20.6–905 ng/L) may be evidence of the direct discharge of untreated sewage and an obvious indicator of the overall concentrations of PPCPs. The PPCPs contamination levels in surface water were increased along with the direction of the water diversion in urban runoff, and decreased by 8–31% due to the increase in volume attributable to the water diversion. The distribution coefficients (Kd) of pollutants in the SPM-water phases (3.0–5.6 L/kg) were two orders of magnitude higher than those in the sediment-water phases (0.3–3.3 L/kg). And the positive correlations between their log Kow and SPM-water log Kd values indicated SPM was the important carrier determining the fate of organic UV filters. Furthermore, the results of ecological risk assessment demonstrated that although the increase in the volume of water caused by the water diversion reduced the overall ecological risks of PPCPs in urban rivers, the current contamination level still represents high risks to algae and fish.

Soluble reactive phosphorus (SRP) that is released from sediment plays an important role in contributing to a lake's eutrophication. Much of the work that has studied sediment release has been conducted in the submerged bottom sediment of lakes. Less attention has paid to the littoral zones near land boundaries where the hydrodynamic disturbance of drying/wetting cycles dominates. To date, the release mechanism under drying/wetting cycles has not been revealed quantitatively. In this study, we conducted a series of laboratory experiments to evaluate the effect of varied frequencies of drying/wetting cycles to the efflux of SRP from sediment. We tested SRP, Fe2+, pH, and redox condition (pE) in overlying water under three frequencies of 24, 9, and 2.77 day−1 (F1, F2, and F3, respectively). SRP concentrations of F1, F2, and F3 experimental conditions were 3.46, 1.73, and 1.38 times that of a static experimental condition, respectively, showing a significant difference (p < 0.05) among the conditions. The overlying water under drying/wetting cycles varied in weak-base and low-redox status, which facilitated ion release. The SRP concentration of the porewater varied with the different frequencies of drying/wetting cycles. These results suggested that the variation of SRP in the porewater was strongly correlated with SRP release (R2 = 0.809). Drying/wetting cycles enhanced the mobilization and release of SRP from the sediment to the overlying water through porewater exchange. The evaluation model emphasized that porewater exchange made the greatest contribution to SRP release and a higher frequency of drying/wetting cycles may have promoted this exchange of porewater between the sediment and overlying water, thus facilitating the release of SRP.

Among the noisiest man-made activities in the seas, emitting very high acoustic energy are the underwater explosions of various objects and ship shock trials. Sound energy emitted by high explosives can be predicted or measured at sea. Sometimes, it can be convenient to apply empirical formulas and scaling laws to approximate the energy of underwater explosions. In addition, at some instances the determination of the spectral properties of the explosions is useful, i.e. when possible animal exposure to impulsive noise has to be evaluated. This paper presents an example of an application of freely available scaling laws and equations for prediction of noise levels of underwater explosions of historical ordnance in the shallow sea environments.Main findings of the study: An available scaling laws applied to model underwater explosion properties; spatial extent of explosion mapped; arising issues of modelling of underwater explosions in the shallow marine areas discussed.

Stormwater is viewed as an alternative resource to mitigate water shortages. However, stormwater reuse is constrained due to the presence of many toxic pollutants such as hydrocarbons. Effective mitigation requires robust mathematical models for stormwater quality prediction based on an understanding of pollutant processes. However, the rise in global temperatures will impose changes to pollutant processes. This study has proposed a new perspective on modelling the build-up process of hydrocarbons, with a focus on volatile organic compounds (VOCs). Among organic compounds, VOCs are the most susceptible to changes as a result of global warming due to their volatility. Seven VOCs, namely, benzene, toluene, ethylbenzene, para-xylene, meta-xylene, ortho-xylene and styrene in road dust were investigated. The outcomes are expected to lay the foundation to overcoming the limitations in current modelling approaches such as not considering the influence of temperature and volatility, on the build-up process. A new conceptualisation is proposed for the classical build-up model by mathematically defining the volatility of VOCs in terms of temperature. Uncertainty in the re-conceptualised build-up model was quantified and was used to understand the build-up patterns in the future scenarios of global warming. Results indicated that for the likely scenarios, the variability in VOCs build-up gradually increases at the beginning of the dry period and then rapidly increases after around seven days, while the build-up reaches a near-constant value in a shorter dry period, limiting the variability. These initial research outcomes need to be further investigated given the expected impacts of global warming into the future.

Development of low-cost cathode materials for Plant-Sediment Microbial Fuel Cells (P-SMFCs) has gained increasing interest, due to improved performance levels in terms of power and pollutant removal. A novel low cost three-dimensional cathode prepared by simple three-step strategy with growth of Co₃O₄ in-situ biofilm was successfully prepared. Different cathodes were applied to the six parallel P-SMFCs systems (reactor: R1-R6), such as graphite felt (GF), Pt/C, GF@Co₃O₄ (non-bonding Co₃O₄ nanowires on GF), GF@SG-Co₃O₄ (using argon as shielding gas (SG)). Its performances (R1, R2: control groups) were evaluated by electricity generation and Cr(VI) reduction at initial cadmium concentrations (4.97, 10.29 and 21.16 mg L⁻¹). A significant Cr(VI) removal efficiency of 99.76%, maximum power density of 75.12 ± 2.90 mW m⁻² and Cr(VI) adsorption capacity of 1.67 mg g⁻¹ were obtained at initial Cr(VI) concentration of 21.16 mg L⁻¹ with non-bonding GF@Co₃O₄ and bio-GF@SG-Co₃O₄ as cathodes. This indicated that these two materials were better than others (GF, Pt/C and GF@Co₃O₄) as cathodes. Characterization analysis including scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Polarization curve, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) showed that high current generation Cr(VI) removal mainly attributed to transportation of plants, adsorption of bio-cathode, formation of a relatively high concentration region and abundant oxygen vacancies of GF@SG-Co₃O₄. The results show that P-SMFCs with GF@SG-Co₃O₄ cathode may be a potentially novel approach for remediating Cr(VI) contaminated waster or soil.

The control of agricultural pests is key to maintain economically viable crops. Increasing environmental awareness, however, is leading to more restrictive European policies regulating the use of certain pesticides due to their impact on human health and the soil system. Given this context, we evaluated the efficacy of three alternatives to the soil fumigant 1,3-dichloropropene (1,3-D), which is currently banned in Europe: two non-fumigant nematicides [oxamyl (OX) and fenamiphos (FEN)] and the soil fumigant dimethyl disulfide (DMDS). We analysed the efficiency of these pesticides against root-knot nematodes and soil fungal pathogens (determined by qPCR) as well as the soil biological quality after treatments application (estimated by enzyme activities). Among treatments, 1,3-D and DMDS significantly reduced nematode populations. FEN was more effective in sandy soil, while OX had no effect in any soil. OX and FEN had no effect on fungal pathogens, whereas DMDS reduced the abundance of Rhizoctonia solani and Fusarium solani at the root level in clay-loam soil. Soil quality decreased after treatment application but then recovered throughout the experiment, indicating the possible dissipation of the pesticides. Our findings support DMDS as a potential sustainable alternative for controlling root-knot nematodes and fungal pathogens due to its effectiveness in both studied soils, although its negative impact on soil biological quality in sandier soils must be taken into account.Main finding of the work. DMDS is a reliable alternative to 1,3-D for controlling agricultural pest but its inhibitory effect on soil enzyme activities varied according to the soil characteristics.

Triphenyl phosphate (TPHP) is one of the major organophosphate esters (OPEs) with increasing consumption. Considering its largely distribution and high toxicity in aquatic environment, it is important to explore an efficient treatment for TPHP. This study aimed to investigate the accelerated degradation of TPHP in a three-electrode single chamber bioelectrochemical system (BES). Significant increase of degradation efficiency of TPHP in the BES was observed compared with open circuit and abiotic controls. The one-order degradation rates of TPHP (1.5 mg L⁻¹) were increased with elevating sodium acetate concentrations and showed the highest value (0.054 ± 0.010 h⁻¹) in 1.0 g L⁻¹ of sodium acetate. This result indicated bacterial metabolism of TPHP was enhanced by the application of micro-electrical field and addition acetate as co-substrates. TPHP could be degraded into diphenyl phosphate (DPHP), hydroxyl triphenyl phosphate (OH-TPHP) and three byproducts. DPHP was the most accumulated degradation product in BES, which accounted more than 35.5% of the initial TPHP. The composition of bacterial community in BES electrode was affected by the acclimation by TPHP, with the most dominant bacteria of Azospirillum, Petrimonas, Pseudomonas and Geobacter at the genera level. Moreover, it was found that the acute toxic effect of TPHP to Vibrio fischeri was largely removed after the treatment, which revealed that BES is a promising technology to remove TPHP threaten in aquatic environment.