We investigated the occurrence and removal of four benzotriazoles (BTs) (benzotriazole: BT; 5-methyl-benzotriazole: 5-TTri; 5-chloro-benzotriazole: CBT; 5,6-dimethyl-benzotriazole: XTri) and six UV filters (benzophenone-3: BP-3; 3-(4-methylbenzylidene)camphor: 4-MBC; octyl 4-methoxycinnamate: OMC; 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chloro benzotriazole: UV-326; 2-(2′-Hydroxy-5′-octylphenyl)-benzotriazole: UV-329; octocrylene: OC) in a full scale municipal wastewater treatment in South Australia. BT, 5-TTri and BP-3 were found as the dominant compounds detected in the wastewater samples with average concentrations up to 5706 ± 928 ng/L, 6758 ± 1438 ng/L and 2086 ± 1027 ng/L in influent, and up to 2439 ± 233 ng/L, 610 ± 237 ng/L and 153 ± 121 ng/L in effluent, respectively. In the biosolid, 4-MBC and OC were found with the highest concentrations of 962 ± 135 ng/g and 465 ± 65 ng/g, respectively. Sorption onto sludge played a dominant role in the removal for UV filters, especially for 4-MBC, UV-326 and OC, which accounted for 54%–92% of influent loads, while biological degradation played a significant role for the other compounds.

Polybrominated diphenyl ethers (PBDEs) were determined in sewage sludge samples collected from eight Italian wastewater treatment plants (WWTPs) between June 2009 and March 2010. Total PBDE concentrations ranged from 158.3 to 9427 ng g⁻¹ dw, while deca-BDE (BDE-209) (concentrations ranging from 130.6 to 9411 ng g⁻¹ dw) dominated the congener profile in all the samples, contributing between 77% and 99.8% of total PBDE. The suitability of using a magnetic particle enzyme-linked immunoassay (ELISA) to analyse PBDEs in sewage sludge was also tested. The ELISA results, expressed as BDE-47 equivalents, were well correlated with those obtained by GC–NCI–MS, with correlation coefficients (r²) of 0.899 and 0.959, depending on the extraction procedure adopted. The risk assessment of PBDEs in sewage sludge addressed to land application was calculated. PECₛₒᵢₗ values compared to the relative PNECₛₒᵢₗ for penta and deca-BDE suggests that there is a low risk to the soil environment.

The anti-microbial substance triclosan can partition to sewage sludge during wastewater treatment and subsequently transfer to soil when applied to land. Here, we describe the fate of triclosan in a one-year plot experiment on three different soils receiving sludge. Triclosan and methyl-triclosan concentrations were measured in soil samples collected monthly from three depths. A large fraction of triclosan loss appeared to be explained by transformation to methyl-triclosan. After 12 months less than 20% of the initial triclosan was recovered from each soil. However, the majority was recovered as methyl-triclosan. Most of the chemical recovered at the end of the experiment (both triclosan and methyl-triclosan) was still in the top 10 cm layer, although there was translocation to lower soil horizons in all three soils. Between 16.5 and 50.6% of the applied triclosan was unaccounted for after 12 months either as a consequence of degradation or the formation of non-extractable residues.

Effects of N deficiency and salinity on root anatomy, permeability and metal (Pb, Zn and Cu) translocation and tolerance were investigated using mangrove seedlings of Rhizophora stylosa. The results showed that salt could directly reduce radial oxygen loss (ROL) by stimulation of lignification within exodermis. N deficiency, oppositely, would reduce lignification. Such an alteration in root permeability may also influence metal tolerance by plants. The data indicated that a moderate salinity could stimulate a lignified exodermis that delayed the entry of metals into the roots and thereby contributed to a higher metal tolerance, while N deficiency would aggravate metal toxicity. The results from sand pot trail further confirmed this issue. This study provides a barrier property of the exodermis in dealing with environments. The plasticity of root anatomy is likely an adaptive strategy to regulate the fluxes of gases, nutrients and toxins at root–soil interface.

Ofloxacin (OFL) was used as a model antibiotic and the quenching of OFL fluorescence by DOM was examined with an emphasis on temperature-dependent quenching kinetics. OFL fluorescence intensity was corrected for inner filter and temperature effects. The kinetics data were fitted well using a two-compartment pseudo first-order kinetics model. Three quenching compartments were identified using this model, namely, a very fast quenching compartment (q₀) and two pseudo first-order quenching compartments (q₁ + q₂). The q₀ values had a positive relationship with temperature, while (q₁ + q₂) were negatively related with temperature. In addition, OFL–DOM binding quantified by (q₁ + q₂) was consistent with binding result obtained from dialysis equilibrium system. We concluded that q₀ was resulted from dynamic quenching, while (q₁ + q₂) was attributed to static quenching. The dynamic quenching of OFL by DOM accounted for 30–90% to the overall quenching and thus was very significant.

This study evaluated the effect of continuous and batch feeding on the removal of 8 pharmaceuticals (carbamazepine, naproxen, diclofenac, ibuprofen, caffeine, salicylic acid, ketoprofen and clofibric acid) from synthetic wastewater in mesocosm-scale constructed wetlands (CWs). Both loading modes were operated at hydraulic application rates of 5.6 cm day⁻¹ and 2.8 cm day⁻¹. Except for carbamazepine, clofibric acid and naproxen, removal in CWs was significantly (p < 0.05) enhanced under the batch versus continuous mode. For all compounds tested except naproxen, values for first-order decay constants (k) for drain and fill operation were higher than that for the continuous mode of operation. Correlation between the distribution coefficient (log Dₒw) and removal efficiencies of pharmaceutical compounds in the CWs, showed that pharmaceutical removal efficiency was significantly (p < 0.1) and inversely correlated with log Dₒw value, but not with log Kₒw value.

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in sediments and benthic invertebrates near submarine municipal outfalls in Victoria and Vancouver, B.C., Canada, two areas with contrasting receiving environments. PBDE concentrations in wastewater exceeded those of the legacy PCBs by eight times at Vancouver and 35 times at Victoria. Total PBDE concentrations in benthic invertebrates were higher near Vancouver than Victoria, despite lower concentrations in sediments, and correlated with organic carbon-normalized concentrations in sediment. Principal Components Analysis indicated uptake of individual PBDE congeners was determined by sediment properties (organic carbon, grain size), while PCB congener uptake was governed by physico-chemical properties (octanol-water partitioning coefficient). Results suggest the utility of sediment quality guidelines for PBDEs and likely PCBs benefit if based on organic carbon-normalized concentrations. Also, where enhanced wastewater treatment increases the PBDEs to particulate organic carbon ratio in effluent, nearfield benthic invertebrates may face increased PBDE accumulation.

The high wastewater volumes produced during citrus production at pre- and post-harvest level presents serious pesticide point-source pollution for groundwater bodies. Biobeds are used for preventing such point-source pollution occurring at farm level. We explored the potential of biobeds for the depuration of wastewaters produced through the citrus production chain following a lab-to-field experimentation. The dissipation of pesticides used pre- or post-harvest was studied in compost-based biomixtures, soil, and a straw-soil mixture. A biomixture of composted grape seeds and skins (GSS-1) showed the highest dissipation capacity. In subsequent column studies, GSS-1 restricted pesticides leaching even at the highest water load (462Lm⁻³). Ortho-phenylphenol was the most mobile compound. Studies in an on-farm biobed filled with GSS-1 showed that pesticides were fully retained and partially or fully dissipated. Overall biobeds could be a valuable solution for the depuration of wastewaters produced at pre- and post-harvest level by citrus fruit industries.

The use of biosolids in agriculture continues to be debated, largely in relation to their metal contents. Our knowledge regarding the speciation and bioavailability of biosolids metals is still far from complete. In this study, a multi-technique approach was used to investigate copper and zinc speciation and partitioning in one contemporary and two historical biosolids used extensively in previous research and field trials. Using wet chemistry and synchrotron spectroscopy techniques it was shown that copper/zinc speciation in the biosolids was largely equivalent despite the biosolids being derived from different countries over a 50 year period. Furthermore, copper speciation was consistently dominated by sorption to organic matter whereas Zn partitioned mainly to iron oxides. These data suggest that the results of historical field trials are still relevant for modern biosolids and that further risk assessment studies should concentrate particularly on Cu as this metal is associated with the mineralisable biosolids fraction.

Predictions of surface water exposure to “down-the-drain” chemicals are presented which employ grid-based spatially-referenced data on average monthly runoff, population density, country-specific per capita domestic water and substance use rates and sewage treatment provision. Water and chemical load are routed through the landscape using flow directions derived from digital elevation data, accounting for in-stream chemical losses using simple first order kinetics. Although the spatial and temporal resolution of the model are relatively coarse, the model still has advantages over spatially inexplicit “unit-world” approaches, which apply arbitrary dilution factors, in terms of predicting the location of exposure hotspots and the statistical distribution of concentrations. The latter can be employed in probabilistic risk assessments. Here the model was applied to predict surface water exposure to “down-the-drain” chemicals in China for different levels of sewage treatment provision. Predicted spatial patterns of concentration were consistent with observed water quality classes for China.