Environmental metabolomics uncovers oxidative stress, amino acid dysregulation, and energy impairment in Daphnia magna with exposure to industrial effluents.

Anthropogenic activities are regarded as point sources of pollution entering freshwater bodies worldwide. With over 350,000 chemicals used in manufacturing, wastewater treatment and industrial effluents are comprised of complex mixtures of organic and inorganic pollutants of known and unknown origins. Consequently, their combined toxicity and mode of action are not well understood in aquatic organisms such as Daphnia magna. In this study, effluent samples from wastewater treatment and industrial sectors were used to examine molecular-level perturbations to the polar metabolic profile of D. magna. To determine if the industrial sector and/or the effluent chemistries played a role in the observed biochemical responses, Daphnia were acutely (48 h) exposed to undiluted (100%) and diluted (10, 25, and 50%) effluent samples. Endogenous metabolites were extracted from single daphnids and analyzed using targeted mass spectrometry-based metabolomics. The metabolic profile of Daphnia exposed to effluent samples resulted in significant separation compared to the unexposed controls. Linear regression analysis determined that no single pollutant detected in the effluents was significantly correlated with the responses of metabolites. Significant perturbations were uncovered across many classes of metabolites (amino acids, nucleosides, nucleotides, polyamines, and their derivatives) which serve as intermediates in keystone biochemical processes. The combined metabolic responses are consistent with oxidative stress, disruptions to energy metabolism, and protein dysregulation which were identified through biochemical pathway analysis. These results provide insight into the molecular processes driving stress responses in D. magna. Overall, we determined that the metabolic profile of Daphnia could not be predicted by the chemical composition of environmentally relevant mixtures. The findings of this study demonstrate the advantage of metabolomics in conjunction with chemical analyses to assess the interactions of industrial effluents. This work further demonstrates the ability of environmental metabolomics to characterize molecular-level perturbations in aquatic organisms exposed to complex chemical mixtures directly.

Brominated flame retardants and perfluoroalkyl acids in groundwater, tile drainage, soil, and crop grain following a high application of municipal biosolids to a field.

Dewatered municipal biosolids (DMB) were applied at a rate of 22Mgdwha-1 to an agricultural field in fall 2008. Concentrations of polybrominated diphenyl ethers (PBDEs; BDE-47, -99, -100, -153, -154, -183, -197, -207, -209), other brominated flame retardants (BFRs; HBB, PBEB, DBDPE, BTBPE) and perfluoroalkyl acids (PFAAs; PFHxS, PFOS, PFDS, PFOSA, PFHpA, PFOA, PFNA, PFDA, PFUnA, PFDoA, PFTA) were monitored in tile drainage, groundwater (2m, 4m and 6m depth), soil cores (0-0.3m) pre- and post-application, DMB aggregates incorporated into the soil post-application, and in wheat (Triticum spp.) planted post-application. Several compounds were detected in soil and water pre-application and on a reference field plot. PBDEs, other BFRs and PFAAs were detected in tile drainage and 2m groundwater throughout the post-application study period; a few PBDEs were also detected sporadically at lower depths in groundwater. Some of these compounds had not been detected pre-application, while some exceeded reference field plot/pre-application levels (some significantly (p<0.05) in tile drainage); both cases indicating biosolid-based water contamination. In DMB aggregates, several PBDE congeners were found to have dissipated exponentially, with reductions >90% in many of them within 1year post-application. Exponential dissipation of other BFRs and PFAAs in DMB aggregates were not significant. No PBDEs, other BFRs, or PFAAs were detected in wheat grain.

Hormones, sterols, and fecal indicator bacteria in groundwater, soil, and subsurface drainage following a high single application of municipal biosolids to a field.

A land application of dewatered municipal biosolids (DMB) was conducted on an agricultural field in fall 2008 at a rate of 22Mg dry weight (dw) ha(-1). Pre- and post- application, hormone, sterol and fecal indicator bacteria concentrations were measured in tile drainage water, groundwater (2, 4, 6m depth), surface soil cores, and DMB aggregates incorporated in the soil (∼0.2m depth) for a period of roughly 1year post-application. Hormones and sterols were detected up to 1year post-application in soil and in DMB aggregates. Hormone (androsterone, desogestrel, estrone) contamination was detected briefly in tile water samples (22d and ∼2months post-app), at lowngL(-1) concentrations (2-34ngL(-1)). Hormones were not detected in groundwater. Sterols were detected in tile water throughout the study period post-application, and multiple fecal sterol ratios suggested biosolids as the source. Coprostanol concentrations in tile water peaked at >1000ngL(-1) (22d post-app) and were still >100ngL(-1) at 6months post-application. Fecal indicator bacteria were detected throughout the study period in tile water, groundwater (⩽2m depth), soil and DMB aggregate samples. These bacteria were strongly linearly related to coprostanol in tile water (R(2)>0.92, p<0.05). The limited transport of hormones and sterols to tile drainage networks may be attributed to a combination of the hydrophobicity of these compounds and limited macroporosity of the field soil. This transitory contamination from hormones and sterols is unlikely to result in any significant pulse exposure risk in subsurface drainage and groundwater.

Pharmaceutical and personal care products in groundwater, subsurface drainage, soil, and wheat grain, following a high single application of municipal biosolids to a field.

Dewatered municipal biosolids (DMBs) were applied to a field at a rate of ~22 Mg dw ha(-1) in October 2008. Pharmaceuticals and personal care products (PPCPs) were monitored in groundwater, tile drainage, soil, DMB aggregates incorporated into the soil post-land application, and in the grain of wheat grown on the field for a period of ~1 year following application. Over 80 PPCPs were analyzed in the source DMB. PPCPs selected for in-depth monitoring included: antibiotics (tetracyclines, fluoroquinolones), bacteriocides (triclosan, triclocarban), beta-blockers (atenolol, propranolol, metaprolol), antidepressants (fluoxetine, citalopram, venlafaxine, sertraline), antifungals (miconazole), analgesics (acetaminophen, ibuprofen) and anticonvulsants (carbamazepine). PPCPs in tile were observed twice, ~3 weeks and 2 months post-application. Of all PPCPs measured in tile drainage, only carbamazepine, ibuprofen, acetaminophen, triclosan, triclocarban, venlafaxine, and citalopram were detected (5-74 ng L(-1)). PPCPs were not detected in groundwater >2 m depth below the soil surface, and concentrations above detection limits at 2 m depth were only observed once just after the first rain event post-application. In groundwater, all compounds found in tile, except carbamazepine, acetaminophen and citalopram, were detected (10-19 ng L(-1)). PPCPs were detected in DMB aggregates incorporated in soil up to 1 year post-application, with miconazole and fluoxetine having the lowest percent reductions over 1 year (~50%). For several compounds in these aggregates, concentration declines were of exponential decay form. No PPCPs were detected in the grain of wheat planted post-application on the field. No PPCPs were ever detected in water, soil or grain samples from the reference plot, where no DMB was applied.

Polybrominated diphenyl ethers, perfluorinated alkylated substances, and metals in tile drainage and groundwater following applications of municipal biosolids to agricultural fields.

Polybrominated diphenyl ethers (PBDEs), perfluorinated alkylated substances (PFAS), and metals were monitored in tile drainage and groundwater following liquid (LMB) and dewatered municipal biosolid (DMB) applications to silty-clay loam agricultural field plots. LMB was applied (93,500 L ha(-1)) in late fall 2005 via surface spreading on un-tilled soil (SS(LMB)), and a one-pass aerator-based pre-tillage prior to surface spreading (AerWay SSD) (A). The DMB was applied (8 Mg d wha(-1)) in early summer 2006 on the same plots by injecting DMB beneath the soil surface (DI), and surface spreading on un-tilled soil (SS(DMB)). Key PBDE congeners (BDE-47, -99, -100, -153, -154, -183, -209) comprising 97% of total PBDE in LMB, had maximum tile effluent concentrations ranging from 6 to 320 ng L(-1) during application-induced tile flow. SS(LMB) application-induced tile mass loads for these PBDE congeners were significantly higher than those for control (C) plots (no LMB) (p<0.05), but not A plots (p>0.05). PBDE mass loss via tile (0-2h post-application) as a percent of mass applied was approximately 0.04-0.1% and approximately 0.8-1.7% for A and SS(LMB), respectively. Total PBDE loading to soil via LMB and DMB application was 0.0018 and 0.02 kg total PBDE ha(-1)yr(-1), respectively. Total PBDE concentration in soil (0-0.2m) after both applications was 115 ng g(-1)dw, (sampled 599 days and 340 days post LMB and DMB applications respectively). Of all the PFAS compounds, only PFOS (max concentration=17 ng L(-1)) and PFOA (12 ng L(-1)) were found above detectable limits in tile drainage from the application plots. Mass loads of metals in tile for the LMB application-induced tile hydrograph event, and post-application concentrations of metals in groundwater, showed significant (p<0.05) land application treatment effects (SS(LMB)>A>C for tile and SS(LMB) and A>C for groundwater for most results). Following DMB application, no significant differences in metal mass loads in tile were found between SS(DMB) and DI treatments (PBDE/PFAS were not measured). But for many metals (Cu, Se, Cd, Mo, Hg and Pb) both SS(DMB) and DI loads were significantly higher than those from C, but only during <100 days post DMB application. Clearly, pre-tilling the soil (e.g., A) prior to surface application of LMB will reduce application-based PBDE and metal contamination to tile drainage and shallow groundwater. Directly injecting DMB in soil does not significantly increase metal loading to tile drains relative to SS(DMB), thus, DI should be considered a DMB land application option.

Pharmaceutical and personal care products in tile drainage following surface spreading and injection of dewatered municipal biosolids to an agricultural field.

Land application of municipal biosolids can be a source of environmental contamination by pharmaceutical and personal care products (PPCPs). This study examined PPCP concentrations/temporally discrete mass loads in agricultural tile drainage systems where two applications of biosolids had previously taken place. The field plots received liquid municipal biosolids (LMB) in the fall of 2005 at an application rate of approximately 93,500 L ha (-1), and a second land application was conducted using dewatered municipal biosolids (DMB) applied at a rate of approximately 8Mg dw ha (-1) in the summer of 2006 [corrected].The DMB land application treatments consisted of direct injection (DI) of the DMB beneath the soil surface at a nominal depth of approximately 0.11 m, and surface spreading (SS) plus subsequent tillage incorporation of DMB in the topsoil (approximately 0.10 m depth). The PPCPs examined included eight pharmaceuticals (acetaminophen, fluoxetine, ibuprofen, gemfibrozil, naproxen, carbamazepine, atenolol, sulfamethoxazole), the nicotine metabolite cotinine, and two antibacterial personal care products triclosan and triclocarban. Residues of naproxen, cotinine, atenolol and triclosan originating from the fall 2005 LMB application were detected in tile water nearly nine months after application (triclocarban was not measured in 2005). There were no significant differences (p>0.05) in PPCP mass loads among the two DMB land application treatments (i.e., SS vs. DI); although, average PPCP mass loads late in the study season (>100 days after application) were consistently higher for the DI treatment relative to the SS treatment. While the concentration of triclosan (approximately 14,000 ng g(-1) dw) in DMB was about twice that of triclocarban (approximately 8000 ng g(-1) dw), the average tile water concentrations for triclosan were much higher (43+/-5 ng L(-1)) than they were for triclocarban (0.73+/-0.14 ng L(-1)). Triclosan concentrations (maximum observed in 2006 approximately 235 ng L(-1)) in tile water resulting from land applications may warrant attention from a toxicological perspective.

Effect of liquid municipal biosolid application method on tile and ground water quality.

This study examined bacteria and nutrient quality in tile drainage and shallow ground water resulting from a fall land application of liquid municipal biosolids (LMB), at field application rates of 93,500 L ha(-1), to silt-clay loam agricultural field plots using two different land application approaches. The land application methods were a one-pass AerWay SSD approach (A), and surface spreading plus subsequent incorporation (SS). For both treatments, it took between 3 and 39 min for LMB to reach tile drains after land application. The A treatment significantly (p < 0.1) reduced application-induced LMB contamination of tile drains relative to the SS treatment, as shown by mass loads of total Kjeldahl N (TKN), NH(4)-N, Total P (TP), PO(4)-P, E. coli., and Clostridium perfringens. E. coli contamination resulting from application occurred to at least 2.0-m depth in ground water, but was more notable in ground water immediately beneath tile depth (1.2 m). Treatment ground water concentrations of selected nutrients and bacteria for the study period ( approximately 46 d) at 1.2-m depth were significantly higher in the treatment plots, relative to control plots. The TKN and TP ground water concentrations at 1.2-m depth were significantly (p < 0.1) higher for the SS treatment, relative to the A treatment, but there were no significant (p > 0.1) treatment differences for the bacteria. For the macroporous field conditions observed, pre-tillage by equipment such as the AerWay SSD, will reduce LMB-induced tile and shallow ground water contamination compared to surface spreading over non-tilled soil, followed by incorporation.