Validation of an Analytical Workflow for the Analysis of Pesticide and Emerging Organic Contaminant Residues in Paddy Soil and Rice.

Contamination of agricultural soil with organic contaminants is a global problem due to the risks associated with food security and ecological sustainability. Besides the use of agrochemicals, hundreds of emerging contaminants enter arable lands through polluted irrigation water. In this study, an analytical workflow based on QuEChERS extraction coupled with LC-MS/MS quantification was applied to measure 65 emerging contaminants (42 pesticides and 23 multiclass industrial chemicals) in soil and rice for the first time. The method was validated on paddy and yard soil and rice plants. A recovery efficiency ranging between 70 and 120% (RSD <20%) was achieved for more than 70% of the analytes. Then, the validated method was used to quantify target contaminants in 22 soil and 9 rice samples collected mainly from paddy fields close to the Ergene River (Turkey), which is a highly polluted river used for irrigation in the region. Pesticide residues were present in all soil samples up to 2.4 mg/kg. However, their concentrations were below their maximum residual limits in rice. Azoxystrobin, prochloraz, propiconazole, imidacloprid, and epoxiconazole were the most frequently detected pesticides. In addition, industrial pollutants such as benzyldimethyldodecylammonium and tris(2-butoxyethyl) phosphate were detected in paddy soil samples at concentrations between 0.1 and 691 µg/kg. Benzyldimethyldodecylammonium and 5-methyl-1H benzotriazole were also measured in rice at concentrations up to 0.26 and 2.13 µg/kg, respectively.

Identification of core micropollutants of Ergene River and their categorization based on spatiotemporal distribution.

Ergene River is heavily utilized for irrigation of fields to grow the main stocks of rice, wheat, and sunflower of Turkey also exported to Europe; therefore, monitoring the river's water quality is crucial for public health. Although the river quality is routinely monitored, the evaluation of pollution based on micropollutants is limited. In this study, we measured 222 organic micropollutants in 300 samples collected from 75 different locations on the Ergene River between August 2017 and May 2018 using direct injection liquid chromatography-tandem spectrometry with optimized scheduled multiple reaction monitoring. In total, 165 micropollutants were detected at a range of concentrations between 1.90 ng/L and 1824.55 µg/L. Sixty-three chemical substances were recurrent micropollutants that were detected at least one location in all seasons. Among them, 41 chemical substances were identified as the core micropollutants of the Ergene River using data-driven clustering methods. Hexa(methoxymethyl)melamine, benzotriazoles, and benzalkonium chlorides were frequently detected core micropollutants with an industrial origin. Besides, diuron, carbendazim, and cadusafos were common pesticides in the river. Core micropollutants were further categorized based on their type of source and environmental behavior using Kurtosis of concentration and load data obtained for each micropollutant. As a result, the majority of the core micropollutants are recalcitrant chemicals either released from a specific source located upstream of the river or have urban and agricultural sources dispersed on the watershed. In this study, we assessed the current state of pollution in the Ergene River at the micropollutant level with a very high spatial resolution and developed a statistical approach to categorize micropollutants that can be used to monitor the extent of pollution and track pollution sources in the river.

Microwave-assisted chemical oxidation of biological waste sludge: simultaneous micropollutant degradation and sludge solubilization.

Microwave-assisted hydrogen peroxide (MW/H2O2) treatment and microwave-assisted persulfate (MW/S2O8(2-)) treatment of biological waste sludge were compared in terms of simultaneous antibiotic degradation and sludge solubilization. A 2(3) full factorial design was utilized to evaluate the influences of temperature, oxidant dose, and holding time on the efficiency of these processes. Although both MW/H2O2 and MW/S2O8(2-) yielded ≥97% antibiotic degradation with 1.2g H2O2 and 0.87 g S2O8(2-) per gram total solids, respectively, at 160 °C in 15 min, MW/S2O8(2-) was found to be more promising for efficient sludge treatment at a lower temperature and a lower oxidant dosage, as it allows more effective activation of persulfate to produce the SO4(-) radical. Relative to MW/H2O2, MW/S2O8(2-) gives 48% more overall metal solubilization, twofold higher improvement in dewaterability, and the oxidation of solubilized ammonia to nitrate in a shorter treatment period.

Treatment of E. coli HB101 and the tetM gene by Fenton's reagent and ozone in cow manure.

The destruction of antibiotic-resistant microorganisms at the source of contamination is necessary due to their adverse effects and to their increasingly widespread occurrence in the environment. To address this problem, Fenton and ozone oxidation processes were applied to synthetically contaminated cow manure to remove the tetM gene and its host, Escherichia coli HB101. The efficiency of the processes was evaluated by enumeration of E. coli HB101 and by PCR amplification of the tetM gene. The results of this study show that 56.60% bacterial inactivation (corresponding to a 0.36 log reduction) was achieved by a Fenton reagent dose of 50 mM H(2)O(2) and 5 mM Fe(2+) without acidifying the manure. Despite the high organic content of cow manure, 98.50% bacterial inactivation (corresponding to a 1.83 log reduction) was obtained by the ozonation process with an applied dose of 3.125 mg ozone/g manure slurry. The PCR study revealed that the band intensity of the tetM gene gradually decreased by increasing the Fenton reagent and the applied ozone dose. However, significantly high doses of oxidants would be required to completely eliminate bacterial pollution in manure.

Evaluation of the interaction between soil and antibiotics.

The aim of this study was to investigate the occurrence of tetracycline and sulfonamide antibiotics in 13 different soil samples collected from agricultural fields. As well as the antibiotic analysis 18 different physicochemical properties of the soil samples were determined in order to establish a relationship between the recovery rates of antibiotics from the samples and the characteristics of the samples that provide critical information for the reliability of an applied antibiotic analysis method. While the concentrations of tetracyclines were 0.025-0.105 mg kg(-1) sulfonamide antibiotics were not detected in any investigated soil samples. The mean recovery rates of tetracyclines and sulfonamides were 84.57 +/- 14.92% and 65.88 +/- 8.56%, respectively. Although, the organic carbon contents and cation exchange capacities of the soil samples exhibited a great variation the results of multivariate statistical analysis indicated that the metal content of soils was the major factor significantly influenced the recovery rates of the antibiotics. The sulfonamide recovery rates were positively influenced by the calcium and magnesium amounts in the soil samples, whereas tetracycline recovery rates were markedly diminished by increasing the amount of these polyvalent metals.

Simultaneous removal of oxytetracycline and sulfamethazine antibacterials from animal waste by chemical oxidation processes.

Simultaneous degradation of oxytetracycline (OTC) and sulfamethazine (SMZ) antibacterials in synthetically contaminated cow manure (20 mg of antibacterials/kg of manure) in the presence and absence of bedding was investigated by the application of ozone, Fenton, and persulfate oxidation processes. Almost the complete removal of antibacterials was attained with all oxidation processes, which were combined with a pretreatment of manure with magnesium (Mg(2+)) salt desorption. Among the investigated oxidation processes, thermally activated persulfate oxidation with 25 mM Na(2)S(2)O(8) at 50 degrees C was also applied to the animal feeding operations wastewater, and the pseudo-first-order degradation rate constants of OTC and SMZ were found as 3.22 and 1.25 (1/h), respectively. Thermally activated persulfate treatment resulted in the reduction of 82% inhibition of OTC and SMZ to 7%, indicating the production of almost nontoxic degradation products in the wastewater.

Investigation of the tetracycline, sulfonamide, and fluoroquinolone antimicrobial compounds in animal manure and agricultural soils in Turkey.

Occurrence of antimicrobial residuals in the environment is of concern because of the emergence and development of antimicrobial-resistance in pathogen bacteria, and the ecotoxicological behaviour of these compounds. Investigation of antimicrobial pollution in animal manure has special importance since they constitute the major source for the dissemination of these chemicals into the environment. Hence, eight animal manure and nine agricultural soil samples from the North part of Marmara Region (Turkey) were collected and analyzed for two tetracyclines (TCs), four sulfonamides (SAs), and two fluoroquinolones (FQs). At least one antimicrobial compound was detected in all the agricultural soil and animal manure samples. The highest antimicrobial concentrations were in general detected in the fresh poultry manure samples. Mean recoveries from spiked soil and manure samples ranged from 60 to 86% and 62 to 77% for TCs, 69 to 101% and 14 to 82% for SAs, and 46 to 55% and 24 to 42% for FQs, respectively. Relationship between the recovery rates of the antimicrobial compounds and sample characteristics was statistically evaluated by means of hierarchical cluster analysis (HCA), and principal component analysis (PCA) followed by multiple stepwise regression (MSR). HCA showed agricultural soil samples with higher di- and trivalent metal contents resulted in higher TC and lower FQ recoveries. TC recoveries from manure were highest in the samples with lowest K, Mg, and Ca content, while FQs were more efficiently extracted from the manure samples with less % organic carbon (OC) content. The findings of HCA for TCs were supported by those of MSR analysis, giving comparable results. In addition, MSR of SA recoveries revealed that the increasing amounts of manure % OC led to lower recoveries.

Comparison of the ozonation and Fenton process performances for the treatment of antibiotic containing manure.

An integrated treatment method based on magnesium salt extraction followed by chemical oxidation was used for the treatment of a veterinary antibiotic, oxytetracycline (OTC) contaminated cow manure since animal manure can be an important source for antibiotic pollution in the environment. Pretreatment with magnesium salt enhanced the efficiencies of subsequent oxidation processes by extracting 63.9% of OTC from the manure thereby making it more favorable for oxidation with the hydroxyl radicals produced by the Fenton and ozone oxidation processes. Both the 24 h Fenton oxidation process with 434 mM H(2)O(2) and 43.4 mM Fe(2+) doses and the 1-h ozonation process with an applied ozone dose of 2.5 mg min(-1) provided more than 90% OTC removal from the manure slurry. However, the second-order OTC removal rate constant of Fenton process (119 M(-1)s(-1)) was remarkably lower than that obtained with the ozonation process (548 M(-1)s(-1)). The oxidant dose was a significant factor for the efficiency of the Fenton treatment but not for the ozone treatment. The efficiencies of both the Fenton and ozone oxidation processes were not affected by the pH adjustment of the manure slurry.

A case study on algal response to raw and treated effluents from an aluminum plating plant and a pharmaceutical plant.

The algal growth responses to the effluents of an aluminum plating plant and to the wastewater from an analgesic/antiinflammatory-drug-producing pharmaceutical plant were investigated. Growth response of the marine alga Dunaliella tertiolecta was monitored by measuring the two response parameters optical density (OD(640)) and in vitro chlorophyll fluorescence for a period of 14 days. Generally, the two response measurements gave similar results for all effluents but the raw effluents of the aluminum plating plant due to the composition of the wastewater. All wastes affected algal growth either by inhibition only or by stimulation at low concentrations and inhibition at high concentrations. Since pollutant tolerance of algae biased toxicity test results, acclimation of algae to the raw effluent of the aluminum plating plant was examined. Although the water quality parameters of treated effluent of both plants were in the permitted range reported by the Turkish Water Pollution Control Act, they inhibited growth at higher concentrations, implying that the two treatment plants were inefficient. Therefore, the importance of toxicity tests in wastewater discharge regulations was emphasized.

Adsorption and degradation of enrofloxacin, a veterinary antibiotic on natural zeolite.

The adsorption of enrofloxacin, a veterinary antibiotic onto natural zeolite and further decontamination of zeolite was investigated in the present study. In the first part of the study, the effects of pH, temperature, and presence of ammonium ion on the adsorption process were examined and evaluated on the basis of Langmuir and Freundlich isotherms. Adsorption of enrofloxacin on natural zeolite was found to be highly pH dependent, exhibiting increases correspondent to decreases in pH. The positive value of enthalpy change showed the endothermic nature of adsorption processes. The presence of ammonium ion enhanced the adsorption of enrofloxacin. In the second part of the study, infrared (IR) spectroscopy, and scanning electron microscopy (SEM) were used for the determination of the modifications on the zeolite surfaces resulting from adsorption and ozone treatment. It was found that ozone at sufficient concentrations over specified time periods was able to decompose the enrofloxacin adsorbed on zeolite.

QSPR study on the bioconcentration factors of nonionic organic compounds in fish by characteristic root index and semiempirical molecular descriptors.

The characteristic root index (CRI) was modeled together with four semiempirical molecular descriptors, namely-energies of the highest occupied and the lowest unoccupied molecular orbital (E(HOMO) and E(LUMO)), heat of formation (DeltaH(f)), and dipole moment (micro)-to predict the fish bioconcentration factor (BCF) of 122 nonionic organic compounds. The best fit equation found by "forward multiple linear regression" showed that the topology based CRI was the most important parameter. The addition of quantum chemical descriptors made only a slight improvement in the predictive capability of the Quantitative Structure-Property Relationship (QSPR) model. The CRI was followed by E(HOMO). A two-parameter equation with a correlation coefficient of r = 0.921 was obtained for a diverse set of nonionic organic chemicals. Statistical robustness of the developed model was validated by modified jackknife tests where random deletion of a class of compounds and specific deletion of a set of compounds were both performed. The predictive accuracy of the proposed model was compared with the commonly used K(ow) model and recently published studies in which BCF models were developed. Particular emphasis has been made to clearly define the boundaries for the application of the alternative developed model as well as the quality of estimates.

Application of advanced oxidation processes to different industrial wastewaters.

This study examines the application of photochemical and non-photochemical advanced oxidation processes on the treatment of textile, Kraft bleaching, photoprocessing, and pharmaceutical wastewaters. Effects of reaction conditions on the treatment efficiency of industrial wastewater have been investigated. The results were evaluated in terms of biodegradability enhancement. The results indicated depending upon the composition of wastewater and applied pretreatment all applied AOPs had an ability to increase the biodegradability of studied wastewaters.

Treatment of pharmaceutical wastewater containing antibiotics by O3 and O3/H2O2 processes.

Ozonation of three different synthetic pharmaceutical formulation wastewater containing two human antibiotics and a veterinary antibiotic has been studied to enhance the their biodegradability. The effects of pH and initial chemical oxygen demand (COD) value as well as addition of hydrogen peroxide on ozonation process were investigated. Total organic carbon (TOC), COD, biochemical oxygen demand (BOD), and aromatic content (UV254) were the parameters followed to evaluate the performance of ozonation process. Comparison of the biodegradability of selected wastewaters containing different antibiotics confirmed that the variation of biodegradability was associated with the target compound. While BOD5/COD ratio of veterinary antibiotic formulation wastewater was increased from 0.077 to 0.38 with an applied ozone dosage of 2.96 g/l, this ratio for human antibiotic I and human antibiotic II was increased from 0 to 0.1 and 0.27 respectively. Moreover the results of this investigation showed that the ozonation process is capable of achieving high levels of COD and aromaticity removals at about their natural pH values.

Advanced oxidation of a reactive dyebath effluent: comparison of O3, H2O2/UV-C and TiO2/UV-A processes.

In the present study the treatment efficiency of different AOPs (O3/OH- H2O2/UV-C and TiO2/UV-A) were compared for the oxidation of simulated reactive dyebath effluent containing a mixture of monochlorotriazine type reactive dyes and various dye auxiliary chemicals at typical concentrations encountered in exhausted reactive dyebath liquors. A525 (color), UV280 (aromaticity) and TOC removal rates were assessed to screen the most appropriate oxidative process in terms of reactive dyebath effluent treatment. Special emphasis was laid on the effect of reaction pH and applied oxidant (O3, H2O2) dose on the observed reaction kinetics. It was established that the investigated AOPs were negatively affected by the Na2CO3 content (= 867 mg/L) which is always present at high concentrations in dychouse effluents since it is applied as a pH buffer and dye fixation agent during the reactive dyeing process. The ozonation reaction exhibited almost instantaneous decolorization kinetics and a reasonable TOC reduction rate. It appeared to be stable under the investigated advanced oxidation conditions and outranked the other studied AOPs based on the above mentioned criteria. Besides, the electrical energy requirements based on the EE/O parameter (the electrical energy required per order of pollutant removal in 1 m3 wastewater) was calculated for the homogenous AOPs in terms of decolorization kinetics. In view of the electrical energy efficiency, ozonation and H2O2/UV-C oxidation at the selected treatment conditions appear to be promising candidates for full-scale dyehouse effluent decolorization.