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Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) may be formed during the manufacture of chlorinated pesticides, and can remain in the products as impurities. However, the contemporary release of PCDD/Fs to the environment from pesticide use is poorly understood. For this study, 27 pesticide formulations were analyzed for PCDD/Fs (n = 23 registered for use in Australia). PCDD/F impurities were present in all samples, ranging from 0.020 to 2100 ng SigmaPCDD/F g(-1) active ingredient (AI). Among current use pesticides, pentachloronitrobenzene (PCNB) contained the highest impurity levels (up to 2000 ng SigmaPCDD/F g(-1) AI and 5.6 ng TEQ g(-1) AI). The quantity of pesticide used in Australia and associated release of PCDD/Fs was estimated for PCNB and phenoxy herbicides (2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB)) using a probabilistic approach. Input parameters to model pesticide use contributed the highest proportions to the variability of the estimated PCDD/F release, and were considered to have the highest uncertainty. Preliminary estimates of PCDD/F release suggest that contaminated pesticides represent an important ongoing PCDD/F source to the Australian environment (10th-90th percentiles for PCNB = 14-42 and 2,4-D/2,4-DB = 0.35-1.6 g TEQ annum(-1)). These results may have global relevance given that many of the pesticides analyzed were imported into Australia, and are used in high volumes in other countries.

In this study, PAH bioavailability was assessed in creosote-contaminated soil following bioremediation in order to determine potential human health exposure to residual PAHs from incidental soil ingestion. Following 1,000 days of enhanced natural attenuation (ENA), a residual PAH concentration of 871 ± 8 mg kg(-1) (∑16 USEPA priority PAHs in the <250 μm soil particle size fraction) was present in the soil. However, when bioavailability was assessed to elucidate potential human exposure using an in vivo mouse model, the upper-bound estimates of PAH absolute bioavailability were in excess of 65% irrespective of the molecular weight of the PAH. These results indicate that a significant proportion of the residual PAH fraction following ENA may be available for absorption following soil ingestion. In contrast, when PAH bioavailability was estimated/predicted using an in vitro surrogate assay (FOREhST assay) and fugacity modelling, PAH bioavailability was up to 2000 times lower compared to measured in vivo values depending on the methodology used.

• Dynamic adsorption of P from water and wastewater by Zr(IV)-loaded okara was tested.• Effects of column design parameters on the adsorption performance were investigated.• The dynamic adsorption capacity of Zr(IV)-loaded okara for P was reasonably high.• The spent column was effectively regenerated with 0.2 M NaOH followed by 0.1 M HCl.• Zr(IV)-loaded okara column was efficient in eliminating P from municipal sewage. This study explores the potential of removing phosphorus from aqueous solutions and sewage by Zr(IV)-loaded okara (ZLO) in the fixed-bed column. Soybean residue (okara) was impregnated with 0.25 M Zr(IV) solution to prepare active binding sites for phosphate. The effect of several factors, including flow rate, bed height, initial phosphorus concentration, pH and adsorbent particle size on the performance of ZLO was examined. The maximum dynamic adsorption capacity of ZLO for phosphorus was estimated to be 16.43 mg/g. Breakthrough curve modeling indicated that Adams-Bohart model and Thomas model fitted the experimental data better than YoonNelson model. After treatment with ZLO packed bed column, the effluent could meet the discharge standard for phosphorus in Australia. Successful desorption and regeneration were achieved with 0.2 NaOH and 0.1 HCl, respectively. The results prove that ZLO can be used as a promising phosphorus adsorbent in the dynamic adsorption system. a b s t r a c t a r t i c l e i n f o

This paper presents a brief review of the international scientific literature of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls (PBBs) in sewage sludge and a survey of these compounds in sewage sludge from 16 Australian wastewater treatment plants (WWTPs). The SigmaPBDE mean concentration in the Australian study was 1137microgkg(-1) dry weight (d.w.) (s.d. 1116) and ranged between 5 and 4 230microgkg(-1)d.w. The urban mean of 1308microgkg(-1) (s.d. 1320) and the rural mean of 911microgkg(-1) (s.d. 831) are not statistically different and are similar to levels in European sludges. Principal components analysis was performed on the data set and revealed that 76% of the data variation could be explained by two components that corresponded to overall concentration of the pentaBDE and the decaBDE commercial formulations. An analysis of variance was performed comparing PBDEs levels at three WWTPs over the years 2005 and 2006, finding differences between treatment plants (BDE-47) but no significant difference in PBDE levels in the years 2005 and 2006. Low levels of BB-153 were detected in all samples of this survey (n=16); mean 0.6microgkg(-1)d.w. (s.d. 0.5). This compound has rarely been reported in any other study of sewage sludges undertaken outside Australia. This work highlights the need for a risk assessment of PBDEs in sewage sludge when used for land application, taking into account typical levels found in Australian sludges and soils.

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Per‐ and polyfluoroalkyl substances (PFAS) have been used in aqueous film‐forming foams used in firefighting, resulting in soil and groundwater contamination and leading to human exposure via animal products grown in contaminated areas. The present study reports the relationship between PFAS intake by hens and the PFAS concentrations in the edible parts of eggs. Laying hens were exposed via drinking water to different concentrations of 4 PFAS compounds (perfluorooctane sulfonate [PFOS], perfluorohexane sulfonate [PFHxS], perfluorooctanoic acid [PFOA], and perfluorohexanoic acid) over 61 d. Egg PFAS residues were assessed for a further 30 d after exposure ceased. The target concentrations of PFAS were 0, 0.3, 3, 30, and 300 µg/L for the treatment groups T1–T5, respectively; and PFAS residues were determined from the eggs collected every second day. There was a linear correlation between the PFAS concentrations in the drinking water of hens and those detected in the egg, which could be useful in estimating PFAS concentrations in the egg by measuring water concentrations. Exposure of hens to drinking water with PFAS concentrations below the Australian Government Department of Health limits (PFOS and PFHxS, 0.07 µg/L; PFOA, 0.56 µg/L), and with no other sources of PFAS exposure, is unlikely to result in egg PFAS concentrations that would exceed the 10% limit set by Food Standards Australia New Zealand for human consumption. Environ Toxicol Chem 2021;40:735–743. © 2020 SETAC