Comprehensive investigation and risk assessment of organic contaminants in Yellow River Estuary using suspect and nontarget screening strategies.

Contaminants of emerging concerns (CECs) include numerous chemicals that may pose known and unknown risks to the ecosystem, and identification and risk ranking of these compounds is essential for the environmental management. In this study, liquid and gas chromatography time-of-flight mass spectrometry (LC-QTOF-MS and GC-QTOF-MS) were used to characterize the occurrence of CECs in the surface water of the Yellow River Estuary (YRE). A total of 295 and 315 chemicals were identified by LC-QTOF-MS and GC-QTOF-MS, respectively. The occurrence of two compounds, erucamide and 2-phenylquinoline, was for the first time reported in the aquatic environment in YRE. The concentrations of 121 CECs, including 35 antibiotics, 49 pesticides and veterinary, 16 polycyclic aromatic hydrocarbons and 21 phthalic acid esters were further quantified by target analysis, which showed the detection of 99 compounds in the surface water in the range of 7.07-4611.26 ng/L. Ecological risks of pollutants based on the risk quotient (RQ) method revealed that 13 pollutants posed ecological risks to the aquatic ecosystem (RQ > 1), and pesticides (n = 12) were the main risk contributors. Here, all CECs data sets were finally transformed and ranked in the framework of the toxicological priority index (ToxPi), and a total of 81 priority control pollutants were identified in the surface water of YRE. This study highlighted the necessity of suspect and nontarget screening for CECs in estuaries, and revealed the importance of localized contamination sources in urban and agricultural environment.

Spatial distribution, receptor modelling and risk assessment of organophosphate esters in surface water from the largest freshwater lake in China.

The occurrence and risk of organophosphate esters (OPEs) has become a global concern in recent years. This study investigated the occurrence, spatial distribution, and potential sources of thirteen OPEs and their associated ecological and human health risks in water samples from the largest freshwater lake, Poyang Lake, together with its five major inflow rivers and the water channel to Yangtze River. The total OPEs concentrations ranged from 38.44 ng/L to 428.94 ng/L, and the largest tributary Ganjiang River was much more polluted than other rivers. Chlorinated OPEs, such as tris (1-chloro­2-propyl) phosphate and tri (2-chloroethyl) phosphate occupied the dominant composition of OPEs in the research area. Principal component analysis with multiple linear regression, positive matrix factorization, and correlation analysis were used to apportion the potential sources of OPEs in surface water. The combined contribution of polyvinyl chloride, polyester resins, and polyurethane foam (68.64%), antifoam agent and hydraulic fluids (21.50%), and the release of decorative materials and electric equipment from indoor (9.86%) were identified as the OPEs sources in the study region. The risk quotients (RQs) showed the ecological risk was negligible, but 2-ethylhexyl diphenyl phosphate exposures posed medium ecological risk to aquatic organisms. The carcinogenic and non-carcinogenic risks of the target OPEs were below the theoretical risk threshold values, however, toddlers were much more sensitive to the OPEs exposure in surface water than teenagers and adults. Oral ingestion was the principal exposure pathway, and the health risk via oral ingestion was 1-2 orders of magnitude higher than dermal contact exposure route.

Vertical profile and assessment of soil pollution from a typical coking plant by suspect screening and non-target screening using GC/QTOF-MS.

A comprehensive workflow for suspect screening and non-target screening with gas chromatography coupled with quadrupole time-of-flight mass spectrometry (GC/QTOF-MS) was used to characterize the pollution characteristics of soil samples in a typical coking plant in China. Suspect screening confirmed 57 chemicals including PAHs, alkyl PAHs, and phthalates contained in high-resolution personal compound database and library (PCDL). Non-target screening detected 88 chemicals from soil samples in the NIST 17 library. A total of 122 chemicals were screened in soil samples, and many of them were of emerging concern. Their presence in the soil obtained from coking operations has been underestimated, such as the oxygenated PAHs (naphtho[2,1-b]furan and 9H-fluoren-9-one), and the alkyl biphenyls compounds (4,4'-dimethylbiphenyl, 3,3'-dimethylbiphenyl, 4-methyl-1,1'-biphenyl and 2,2',5,5'-tetramethyl-1,1'-biphenyl). Toxicity assays by luminescent bacteria proved that the extracts from soil samples at different depths showed varying toxicity to V. qinghaiensis sp.-Q67. Soil extracts from a depth of 20-40 cm exhibited the greatest toxicity to luminescent bacteria compared with the other six-layered soil samples, which was correlated with the number of detectable pollutants and total organic carbon content. This study provided a screening method for suspect and non-target contaminants in urban industrial soil sites, which was important in identifying localized contamination sources.

Aqueous chlorination of ephedrine: Kinetic, reaction mechanism and toxicity assessment.

Ephedrine (EPH) is widely detected in the water environment, because it is the major ingredient in drugs treating influenza, asthma or hypotension, and is also a highly sought-after chemical precursor in the illicit manufacture of methamphetamine. In this study, transformation of EPH during the chlorination process was investigated for the first time, and the impact of water parameters including pH, different cations and anions on EPH transformation was evaluated as well. The degradation of EPH in the presence of NaClO fit the second order reaction kinetics, with a rate constant of 7.43 × 102 ((mol·L-1)-1·min-1). Increasing the dosage of NaClO increased the observed pseudo first order rate constant for EPH degradation (kobs). Degradation rate of EPH decreased with the increasing pH from 2.0 to 10.0, due to the formation of a chlorammonium intermediate that reacted with NaClO. Low concentration of Br- and I- did not exert significant influence on the degradation of EPH, while at high concentrations a promotive effect was observed. Other ions including Fe3+, Cu2+, NO3-, SO42-, Mg2+ and Ca2+ exerted negative effects even at relatively low concentrations. Based on the degradation products/intermediates identified by UPLC-MS/MS, the EPH degradation pathways were proposed. The reaction mechanism involved in the EPH degradation included dehydration, hydroxylation, deamination and demethylation. Toxicity assays by V. qinghaiensis sp. nov proved that the EPH transformation products were much more toxic than the parent compound. Results indicated that chlorination is an effective approach for the elimination of EPH in the aquatic environment, however, attention should be paid to its toxicity involvement during the chlorination process.

Occurrence and Risk Assessment of Antibiotics in Manure, Soil, Wastewater, Groundwater from Livestock and Poultry Farms in Xuzhou, China.

Antibiotics in manure, soil, wastewater, and groundwater samples from the livestock and poultry farms in Xuzhou City were investigated in the present study. The concentrations of antibiotics in all matrices varied greatly among farms. Total concentrations of fluoroquinolones and macrolides were much higher than those of sulfonamides in manures and soil samples. Total concentrations of antibiotics in wastewater of livestock farms were higher than those of poultry farm. Josamycin (JM) and tilmicosin (TIL) accounted for more than 74% of the nine macrolides in all groundwater samples. Sulfamethizole (SMT), fleroxacin (FLE), cinoxacin (CIN) and JM were the main antibiotics detected in manure and soil samples, while sulfamethoxypyridazine (SMP), sulfameter (SME), SMT, FLE, JM and TIL accounted for a large proportion of antibiotics in surface and groundwater. The risk assessment of target antibiotics revealed that JM in wastewater showed relatively high RQs for aquatic organisms.

Occurrence, distribution, environmental risk assessment and source apportionment of polycyclic aromatic hydrocarbons (PAHs) in water and sediments of the Liaohe River Basin, China.

The occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) were investigated in water and sediments in Liaohe River Basin. The total PAH concentrations ranged from 111.9 to 2,931.6 ng/L in water and from 92.2 to 295,635.2 ng/g dry weight (dw) in sediments. The PAHs in water were dominated by 2-, 3- and 4-ring PAHs, which accounted for 42.8 %, 39.4 % and 14.2 % of the total PAHs, respectively, while in sediment PAHs were dominated by 3-, 4- and 5-ring PAHs, which accounted for 26.5 %, 44.2 % and 17.4 % of the total PAHs, respectively. The benzo[a]pyrene equivalents for water samples showed that in 37 out of 50 sites the values were greater than the national standard, and the environmental risk assessment indicated that high environmental risk of PAHs existed in sediments. Using the molecular ratio method for the source identification it was concluded that PAHs were determined to be from mixed sources (petroleum and combustion) in Liaohe River system and combustion sources in Daliao River system.