The occurrence of 14 endocrine disrupting compounds (EDCs), pharmaceuticals and personal care products (PPCPs) in influents, effluents and sludge from five wastewater treatment plants (WWTPs) in ...southern California was studied in winter and summer. All 14 compounds were detected in influent samples from the five WWTPs except for estrone. Paracetamol, naproxen and ibuprofen were the dominant compounds, with mean concentrations of 41.7, 35.7 and 22.3μg/L, respectively. The treatment removal efficiency for most compounds was more than 90% and concentrations in the effluents were relatively low. Seasonal variation of the compounds' concentration in the wastewater was significant: the total concentration of each compound in the wastewater was higher in winter than in summer, which is attributed to more human consumption of pharmaceuticals during winter and faster degradation of the compounds in summer. The highest concentrations of triclosan and octylphenol were detected in sewage sludge, with mean concentrations of 1505 and 1179ng/g, respectively. Risk quotients (RQs), expressed as the ratios of environmental concentrations and the predicted no-effect concentrations (PNEC), were less than unity for all the compounds except for estrone in the effluents, indicating no immediate ecological risk is expected. However, RQs were higher than unity for 2 EDCs (estrone and octylphenol) and carbamazepine in sludge samples, indicating a significant ecotoxicological risk to human health. Therefore, appropriate treatment of sewage sludge is required before its application.
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► We took influent, effluent and sludge sample from 5 WWTPs in California in 2 seasons. ► We investigated the occurrence of 14 EDCs and PPCPs in the samples. ► Seasonal variations of compounds in the wastewater were significant. ► Most of selected compounds in influents were degraded during the treatment. ► RQ were lower than unity in effluent but higher than unity for 3 chemicals in sludge.
In this study, an efficient full Bayesian approach is developed for the optimal sampling well location design and source parameters identification of groundwater contaminants. An information measure, ...i.e., the relative entropy, is employed to quantify the information gain from concentration measurements in identifying unknown parameters. In this approach, the sampling locations that give the maximum expected relative entropy are selected as the optimal design. After the sampling locations are determined, a Bayesian approach based on Markov Chain Monte Carlo (MCMC) is used to estimate unknown parameters. In both the design and estimation, the contaminant transport equation is required to be solved many times to evaluate the likelihood. To reduce the computational burden, an interpolation method based on the adaptive sparse grid is utilized to construct a surrogate for the contaminant transport equation. The approximated likelihood can be evaluated directly from the surrogate, which greatly accelerates the design and estimation process. The accuracy and efficiency of our approach are demonstrated through numerical case studies. It is shown that the methods can be used to assist in both single sampling location and monitoring network design for contaminant source identifications in groundwater.
Key Points:
Optimal monitoring network is decided by Bayesian experimental design
Contaminant source is identified by MCMC
Sparse grid is used to improve computational efficiency
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•Mycobacterium sp. WY10 is an efficient PAHs-degrader with 53 functional genes.•A detailed PHE and PYR metabolism maps were constructed with metabolic results.•PHE was degraded in a ...dominant phthalate pathway and a minor salicylate pathway.•Both phthalate and salicylate pathways played important roles on PYR degradation.
Mycobacterium sp. WY10 was a highly effective PAHs-degrading bacterium that can degrade phenanthrene (PHE, 100 mg L−1) completely within 60 h and 83% of pyrene (PYR, 50 mg L-1) in 72 h. In this study, ten and eleven metabolites, respectively, were identified in PHE and PYR degradation cultures, and a detailed PHE and PYR metabolism maps were constructed based on the metabolic results. The strain WY10 degraded PHE and PYR with initial dioxygenation mainly on 3,4- and 4,5-carbon positions, respectively. Thereafter, PYR degradation entered the PHE degradation pathway via the ortho-cleavage. It was observed that the “lower pathway” of PHE and PYR degradations were different. Based on the kinetics of residual metabolites, PHE was degraded in a dominant phthalate pathway and a minor salicylate pathway. However, both phthalate and salicylate pathways played important roles on PYR degradation. The WY10 genome revealed there were fifty-three genes related to PAHs degradations, including a complete gene set for PHE and PYR degradation via the phthalate pathway. The candidate gene/ORF, BOH72_19755, encoding salicylate synthase might contribute in the salicylate pathway.
A greenhouse pot experiment was conducted to study the effects of conventional nitrogen fertilization on soil acidity and salinity. Three N rates (urea; N0, 0 kg N ha
−1
; N1, 600 kg N ha
−1
; and ...N2, 1,200 kg N ha
−1
) were applied in five soils with different greenhouse cultivation years to evaluate soil acidification and salinization rate induced by nitrogen fertilizer in lettuce production. Both soil acidity and salinity increased significantly as N input increased after one season, with pH decrease ranging from 0.45 to 1.06 units and electrolytic conductivity increase from 0.24 to 0.68 mS cm
−1
. An estimated 0.92 mol H
+
was produced for 1 mol (NO
2
−
+ NO
3
−
)-N accumulation in soil. The proton loading from nitrification was 14.3–27.3 and 12.1–58.2 kmol H
+
ha
−1
in the center of Shandong Province under N1 and N2 rate, respectively. However, the proton loading from the uptake of excess bases by lettuces was only 0.3–4.5 % of that from nitrification. Moreover, the release of protons induced the direct release of base cations and accelerated soil salinization. The increase of soil acidity and salinity was attributed to the nitrification of excess N fertilizer. Compared to the proton loading by lettuce, nitrification contributed more to soil acidification in greenhouse soils.
Pharmaceuticals and personal care products (PPCPs) are emerging contaminants in the environment, which have drawn popular concerns recently. Most studies on the environmental fate of PPCPs have ...focused on their behaviors during wastewater treatment processes, in aquatic environments, and in the sludge, however, little is known about their behavior in agricultural soils. In this study, adsorption and degradation of six selected PPCPs, including clofibric acid, ibuprofen, naproxen, triclosan, diclofenac and bisphenol A have been investigated in the laboratory using four US agricultural soils associated with reclaimed wastewater reuse. Adsorption test using a batch equilibrium method demonstrated that adsorption of all tested chemicals in soils could be well described with Freundlich equation, and their adsorption affinity on soil followed the order of triclosan
>
bisphenol A
>
clofibric acid
>
naproxen
>
diclofenac
>
ibuprofen. Retardation factor (
R
F
) suggested that ibuprofen had potential to move downward with percolating water, while triclosan and bisphenol A were readily retarded in soils. Degradation of selected PPCPs in soils generally followed first-order exponential decay kinetics, with half-lives ranging from 0.81 to 20.44
d. Degradation of PPCPs in soils appeared to be influenced by the soil organic matter and clay contents. Sterilization generally decreased the degradation rates, indicating microbial activity played a significant role in the degradation in soils. The degradation rate constant decreased with increasing initial chemical concentrations in soil, implying that the microbial activity was inhibited with high chemical loading levels.
Pharmaceuticals and personal care products (PPCPs) are one class of the most urgent emerging contaminants, which have drawn much public and scientific concern due to widespread contamination in ...aquatic environment. Most studies on the environmental fate and behavior of PPCPs have focused on nonsteroidal anti-inflammatory drugs. Some other compounds with high concentrations were less mentioned. In this study, sorption and degradation of five selected PPCPs, including bisphenol A (BPA), carbamazepine (CBZ), gemfibrozil (GFB), octylphenol (OP), and triclosan (TCS) have been investigated using three different soils. Sorption isotherms of all tested PPCPs in soils were well described by Freundlich equation. TCS and OP showed moderate to strong sorption, while the sorption of GFB and CBZ in soils was negligible. Degradation of PPCPs in three soils was generally fitted first-order exponential decay model, with half-lives (
t
1/2
) varying from 9.8 to 39.1 days. Sterilization could prolong the
t
1/2
of PPCPs in soil, indicating that microbial activity played an important role in the degradation of these chemicals in soils. Degradation of PPCPs in soils was also influenced by the soil organic carbon (
f
oc
) contents. Results from our data show that sorption to the soils varied among the different PPCPs, and their sorption affinity on soil followed the order of TCS > OP > BPA > GFB > CBZ. The degradation of the selected PPCPs in soil was influenced by the microbial activity and soil type. The poor sorption and relative persistence of CBZ suggest that it may pose a high leaching risk for groundwater contamination when recycled for irrigation.
► We developed a rapid and reliable analytical method for determination of 14 PPCPs and EDCs in sewage sludge. ► The method is based on ultrasonic extraction, clean-up on Envi-carb cartridge, ...derivatized with MTBSTFA, and analyzed by GC–MS. ► This method was applied to sewage sludge samples from 4 STPs in southern California.
Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) have been acknowledged as emerging pollutants due to widespread contamination in environment. A rapid and reliable analytical method, based on ultrasonic extraction, clean up on Envi-carb cartridge, derivatized with N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide (MTBSTFA), and analyzed by gas chromatography–mass spectrometry (GC–MS), was developed for determination of 4 EDCs (bisphenol A, estrone, nonylphenol and octylphenol) and 10 PPCPs (acetylsalicylic acid, carbamazepine, clofibric acid, diclofenac, gemfibrozil, ibuprofen, ketoprofen, naproxen, paracetamol and triclosan) in sewage sludge. Mean recoveries of the target analytes, at different spike levels (40, 300 and 2000ng/g), ranged from 57.9% to 103.1%. Relative standard deviations (RSDs) were in the range of 1.3–9.5% at different spiked levels. The limit of quantification (LOQ) ranged from 4.7 to 39ng/g. The method was applied to sewage sludge samples from sewage treatment plants (STPs) in southern California. High concentrations of PPCPs and EDCs were found in sewage sludge, ranging from 1502 to 5327ng/g dry weight. Appropriate disposal of sewage sludge was required to avoid secondary contamination.
The effect of reclaimed wastewater irrigation on the alteration of soil properties and accumulation of trace metals in soil profiles was investigated by monitoring different plots from Palmdale, ...California that had been irrigated with effluents for various lengths of time (3, 8, and 20 years, respectively). The non-effluent-irrigated plot served as the control and provided reference “background” values. Total metals at different soil depths were analyzed by acid digestion, and EDTA-extractable metals were analyzed as available fraction. Results show that soil pH values were significantly (
p
<
0.05) lowered in plots with 20-year irrigation to a depth of 140
cm, while EC was elevated for all three plots compared with control. OM, TC and TN contents increased in the top 10-cm soil layers in plots with 8- and 20-year effluent irrigation. Irrigation with effluents also increased both the total and EDTA-extractable metals in the fields. It showed that long-term effluent irrigation could be of agricultural interest due mainly to its organic matter concentrations and nutrients input, however, trace contaminants such as heavy metals in the upper horizons may be accumulated, which may eventually lead to deterioration of soil and groundwater quality and affect the sustainability of land-based disposal of effluent.
The influences of different N fertilization rates and soil salinity levels on the growth and nitrogen uptake of cotton was evaluated with a pot experiment under greenhouse conditions. Results showed ...that cotton growth measured as plant height was significantly affected by the soil salinity and N-salinity interaction, but not by N alone. Cotton was more sensitive to salinity during the emergence and early growth stages than the later developmental stages. At low to moderate soil salinity, the growth inhibition could be alleviated by fertilizer application. Soil salinity was a dominated factor affecting cotton's above-ground dry mass and root development. Dry mass of seed was reduced by 22%, 52%, and 84% respectively, when the soil salinity level increased from control level of 2.4 dS m⁻¹ to 7.7 dS m⁻¹, 12.5 dS m⁻¹ and to 17.1 dS m⁻¹, respectively. N uptake increased with N fertilization at adequate rates at both low and medium soil salinities but was not influenced by over N fertilization. At higher salinities, N uptake was independent of N rates and mainly influenced by soil salinity. The uptake of K decreased with soil salinity. The concentration of Na, Cl and Ca in plant tissues increased with soil salinity with highest concentrations in the cotton leaf.
Microbial ecological studies have been remarkably promoted by the high-throughput sequencing approach with explosive information of taxonomy and relative abundance. However, relative abundance does ...not reflect the quantity of the microbial community and the inter-sample differences among taxa. In this study, we refined and applied an integrated high-throughput absolute abundance quantification (iHAAQ) method to better characterize soil quantitative bacterial community through combining the relative abundance (by high-throughput sequencing) and total bacterial quantities (by quantitative PCR). The proposed iHAAQ method was validated by an internal reference strain EDL933 and a laboratory strain WG5. Application of the iHAAQ method to a soil phenanthrene biodegradation study showed that for some bacterial taxa, the changes of relative and absolute abundances were coincident, while for others the changes were opposite. With the addition of a microbial activity inhibitor (NaN
), the absolute abundances of soil bacterial taxa, including several dominant genera of
,
, and
, decreased significantly, but their relative abundances increased after 28 days of incubation. We conclude that the iHAAQ method can offer more comprehensive information to reflect the dynamics of soil bacterial community with both relative and absolute abundances than the relative abundance from high-throughput sequencing alone.
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