The distribution and potential toxicity of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Liaohe River Basin were investigated in this study. Total concentrations of 16 PAHs (∑PAH16) ranged from 82.5 to 25374.4 μg/kg averaging 3149.2 μg/kg. Three predominant PAHs were fluoranthene, phenanthrene, and pyrene. In Liao River, two-to-three-ring PAHs were dominant taking up 67.2–92.5 % of ∑PAH16, whereas sediments in Daliao River system mainly contained four-to-six-ring PAHs ranging from 47.8 to 83.7 %. Both petrogenic and pyrogenic sources contributed to the PAH pollution based on diagnostic ratios. The empirical and mechanistic sediment quality guidelines were used to estimate the toxicity risk of PAHs to benthic organisms. The ∑PAH16 in all sediments were significantly lower than probable effect concentrations (PEC), while ∑PAH16 at nine sites of the Daliao River system were between threshold effect concentrations (TEC) and PEC, suggesting that adverse effects were possible at the nine sites. The only individual PAH was acenaphthene whose concentrations were above PEC at some sites, indicating its potential toxicity. Based upon equilibrium partitioning theory and narcosis model, the obtained toxic units for PAH mixtures at all sites were far less than one, implying that the levels of PAH mixtures were acceptable for the protection of benthic fauna. The two evaluation methods lead to the consistent results that benthic organisms inhabiting in the sediments of Liaohe River Basin have no or low risk of adverse effects resulting from exposure to PAHs.

Accurate determination of polycyclic aromatic hydrocarbons (PAHs) in surface waters is necessary for protection of the environment from adverse effects that can occur at concentrations which require preconcentration to be detected. In this study, an effective solid phase extraction (SPE) method based on cetyltrimethylammonium bromide (CTAB)-coated Fe3O4 magnetic nanoparticles (MNPs) was developed for extraction of trace quantities of PAHs from natural waters. An enrichment factor of 800 was achieved within 5 min by use of 100 mg of Fe3O4 MNPs and 50 mg of CTAB. Compared with conventional liquid–liquid extraction (LLE), C18 SPE cartridge and some newly developed methods, the SPE to determine bioaccessible fraction was more convenient, efficient, time-saving, and cost-effective. To evaluate the performance of this novel sorbent, five natural samples including rainwater, river waters, wastewater, and tap water spiked with 15 PAHs were analyzed by use of ultraperformance, liquid chromatography (UPLC) with fluorescence detection (FLD). Limits of determination (LOD) of PAHs (log Kow ≥ 4.46) ranged from 0.4 to 10.3 ng/L, with mean recoveries of 87.95 ± 16.16, 85.92 ± 10.19, 82.89 ± 5.25, 78.90 ± 9.90, and 59.23 ± 3.10% for rainwater, upstream and downstream river water, wastewater, and tap water, respectively. However, the effect of dissolved organic matter (DOM) on recovery of PAHs varied among matrixes. Because of electrostatic adsorption and hydrophobicity, DOM promoted adsorption of Fe3O4 MNPs to PAHs from samples of water from the field. This result was different than the effect of DOM under laboratory conditions. Because of competitive adsorption with the site of action on the surface of Fe3O4 MNPs for CTAB, recoveries of PAHs were inversely proportional to concentrations of Ca2+ and Mg2+. This novel sorbent based on nanomaterials was effective at removing PAHs at environmentally relevant concentrations from waters containing relevant concentrations of both naturally occurring organic matter and hardness metals.

•This is the first report about surfactant-modified MLDH used in extraction of PAEs.•The method has advantages in nano/mesoporous, self-assembly, and magnetic character.•The synthetic process of flowerlike MLDH is time-saving and high-producing.•The special shell structure improves extraction efficiency and adsorption capacity.•The extraction process can be completed within 15 min due to magnetic separation.A novel type of layered, flowerlike magnetic double hydroxide (MLDH) nanoparticles modified by surfactants has been successfully synthesized and was applied as an effective sorbent for pre-concentration of several phthalate ester pollutants (PAEs) from water prior to quantification. The MLDH was obtained via a simple ultrasound-assisted method by using silica coated Fe3O4 as the core and anisotropic Mg–Al layered double hydroxide (Mg–Al LDH) nanocrystals as the shell to which analytes were absorbed. Orientation and dimensionality hierarchical structure as well as the large expandable interlayer free space and positive charge of the Mg–Al LDH shell make it easier to form anionic surfactant micelles on its surface via self-assembly. Due to its high adsorption area, compared with non-mesoporous nano solid-phase extraction agents, mesoporous channel shell and reduction diffusion path, MLDH exhibited high extraction efficiency of organic target residues. Under optimized conditions, with a total of 30 mg of adsorbant added to from samples containing 400 mL water from the environment recoveries of DPP, DBP, DCP and DOP were consistent with ranges of 69–101%, 79–101%, 86–102% and 63–100%, respectively. Standard deviations of recoveries ranged from 1 to 7%, respectively and the method was sensitive with limits of detection of 12.3, 18.7, 36.5 and 15.6 ng L−1. To the best of our knowledge, this is the first report of use of surfactant-modified MLDH nanoparticles and its application as adsorbent to pre-concentration of PAEs from environmental water samples prior to instrumental analyses.

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.

The occurrence and distribution of 19 antibiotics including ten sulfonamides, four quinolones, three tetracyclines and two macrolides in water, sediment, and biota samples from the Liao River Basin, China were investigated in the present study. The samples were collected in May 2012, and laboratory analyses revealed that antibiotics were widely distributed in the Liao River Basin. Macrolides made up the majority of antibiotics in the water ranging from not detected (ND) to 3162.22 ng L−1, while tetracyclines and macrolides were the predominant antibiotics in the sediments, ranging from ND to 404.82 μg kg−1 (mean 32.11 μg kg−1 dw) and ND to 375.13 (mean 32.77 μg kg−1 dw), with detection frequencies of 37.3% and 38.1%, respectively. In biological samples, quinolones were the most frequently detected antibiotics (57.1–100%), with concentrations ranging from 286.6–1655.3 μg kg−1. The highest bioaccumulation factor (BAF) of 45407 L kg−1 was found for enrofloxacin. The phase distribution calculation showed that tetracyclines were the most strongly adsorbed antibiotics in the sediment, with the highest pseudo-partitioning coefficient values, ranging from 1299 to 1499 L kg−1. The geographical differences of antibiotic concentrations were largely due to anthropogenic activities and the sewage discharges from the local cities along the rivers.

In this study, the 30-day aerobic microorganism-mediated biodegradation of polycyclic aromatic hydrocarbons (PAHs) was investigated in four size fractions (i.e., <0.002, 0.002–0.031, 0.031–0.063 and >0.063 mm) of sand-dominated sediment S1 and mud-dominated S2 collected from intertidal zones in Bohai Bay (China). Prior to biodegradation, the total quantity of phenanthrene, fluoranthene and pyrene comprised more than 80 % of the total quantity of 16 EPA-priority PAHs in each size fraction, with the exception of 70.33 % found in the >0.063 mm fraction of sediment S1. Among the three dominant compounds, the intermediate size fraction (0.031–0.063 mm) showed higher levels of biodegradation than other size fractions in sediment S1 and S2. After pooling data from sediment S1 and S2 for joint analysis, it was observed that the biodegraded portion of the three dominant compounds showed negative correlations with both total organic carbon (TOC) and humic coverage index (HCI) in the size fractions. The observed negative correlation with TOC was in agreement with findings in many other studies, but the negative correlation with HCI had not been observed in early studies, which only investigated aged sediment/soil samples. The findings in this study indicated that the greatest bioavailability of PAHs in intertidal surface sediment may be present in sediment particles of intermediate size and mobility, and that intertidal sediment particles are less likely to experience sufficient ageing given periodical tidal disturbance. These findings have important implications for the assessment of the environmental fate of PAHs in intertidal regions.

Taihu lake has become a hot spot internationally due to its algae bloom. However, its natural water chemistry (major ions) received little attention though it is equally important for drinking water and aquatic ecology. Using historical data (1950s–2012) we explored the drastic change of Taihu water chemistry over the past six decades and the driving factors. Results show that major ions increased around 2–7-fold and TDS increased nearly 3-fold during the last 60 years. The dominant cation has shifted from Ca2+ to Na+, and the current Cl– is dominant over HCO3–, the predominant anion before the 2000s. Analyses show that population increase and human activities were the major driving factors responsible for the drastic change. Whereas the mechanism of increase was different for ions, i.e., Na+ and Cl– increase was directly related to the population increase and sewage discharge in the basin; SO42- was related to atmospheric deposition derived from increasing coal consumption and SO2 emissions; hardness (Ca and Mg) increase was closely linked to the acidic precipitation. No increase trend of HCO3– was attributable to frequent outbreaks of algae bloom which consumed HCO3–. Estimation indicated that sewage discharge in the basin contributed 23% to the lake in terms of Cl–, exceeding the contribution from rock weathering. Current water chemistry of Taihu lake has become “anthropogenic dominance” from its original rock dominance.

The present water pollution situation at watershed level in China has been systematically analyzed. The causes of water pollution are attributed to the extensive economic developmental pattern, poor wastewater treatment, and a lack of nonpoint pollution control. The problems of water pollution control at watershed level include a lack of thought and approach, developmental delay in the environmental standard system, an inadequate monitoring ability, and an inefficient implementation of laws and regulations. From 2006 to 2020, water pollution control and governance will be a national key specific project of science and technology in China. The strategies of this project include establishing a water pollution control system at watershed level, orienting a healthy aquatic ecosystem, conducting risk management, and using comprehensive methods. The goal is to establish and complete a technological system of pollution control and management in three five-year phases. The main tasks are to develop common technologies, management systems, and mechanisms for lake eutrophication control, river pollution control, urban water environmental pollution control, potable water safety, and water environmental management. The bottlenecks of water pollution control and management in China could be systematically removed, and the demonstration of the system engineering approach will be conducted at selected key watersheds.

The contamination levels and distribution characters of heavy metals in coastal waters and sediments from Tianjin Bohai Bay, China were examined. Pb and Zn were found as the main heavy metal pollutants in the coastal waters of the bay. High levels of Pb and Zn appeared especially near the estuary, indicating that river discharge was the main pollution source. Moreover, atmospheric deposition resulted in Pb contamination in the middle of the embayment. Analysis of data for the period 1987–2004 indicated that Pb pollution in coastal waters of Tianjin Bohai Bay originated primarily from river discharge before 2001. Pb levels did not decrease after 2001 when annual runoff levels declined; indicating that Pb pollution by atmospheric deposition had increased due to the use of leaded petrol in motorcars. Pb, Zn, and Cd were the dominant polluting elements in surficial sediments from Tianjin Bohai Bay, with levels in excess of the corresponding upper limits of environmental background values. High concentrations of polluting elements were found in tidal sediments near water bodies such as Qihe and Dagu estuaries.

This paper is to examine the water quality of the Yellow River basin on the basis of collated data of nitrogen (40 years) and phosphorus (20 years), and also of the relevant chemical fertilizer application, population, and industrial wastewater, etc. Relationship among these elements was discussed in order to explore their causal links, in relation to the temporal variation of nitrogen and phosphorus transportation. Results indicate that the transported nitrogen load in the lower Yellow River has had an increasing trend during the past 40 years but declined considerably in the later 1990s due to the reduction in flow discharge that led to desiccation of the lower reaches of the Yellow River. Whereas, nitrogen contribution to the estuary from Huayuankou to Lijin reach was minus due to the large amount of water diversion from the Yellow River for irrigation purpose. Phosphorus content fluctuated within a certain range without any tendency, but also decreased in the later 1990s due to the desiccation in the lower reaches. Our analysis indicates that nitrogen load in the Yellow River has been mainly impacted by population growth and nitrogen fertilizer application, but showed no statistically significant relationship with wastewater loads. In contrast, total phosphorus content in the Yellow River showed no relationship with population, fertilizer use and wastewater discharge in the basin, but presented significant correlation with suspended solids concentration of the Yellow River. Calculations indicate that the phosphorus content in suspended solids of the Yellow River was 0.54 g/kg, which is quite close to the background value of phosphorus in the soil of the Loess Plateau – the intensive soil erosion area in China, through which the Yellow River flows. Therefore, we conclude that phosphorus transportation in the Yellow River is dominantly controlled by soil erosion from the Loess Plateau. The results are significant for estuarine management in that nitrogen, a key factor in marine eutrophication, is chiefly from anthropogenic sources whereas the large phosphorus loads are controlled by erosion of loess soils.

This paper presents some points of view on the approach of estuarine ecosystem health scientific research based project experience of the Chinese Research Academy of Environmental Sciences (CRAES). A practical approach (functional zone designation, classification, grading and scheduling) is introduced for managing estuarine ecosystem health at the drainage basin scale. The importance of habitat assessment and functional zone designation is emphasized. The principles for selecting evaluation indicators are presented. The paper noted that Chinese national environmental quality standards should be further developed for emerging pollutants. Special attention should be given to sediment which is important contamination carriers and potential pollution sources.

The occurrence and distribution of 19 antibiotics including ten sulfonamides, four quinolones, three tetracyclines and two macrolides in water, sediment, and biota samples from the Liao River Basin, China were investigated in the present study. The samples were collected in May 2012, and laboratory analyses revealed that antibiotics were widely distributed in the Liao River Basin. Macrolides made up the majority of antibiotics in the water ranging from not detected (ND) to 3162.22 ng L−1, while tetracyclines and macrolides were the predominant antibiotics in the sediments, ranging from ND to 404.82 μg kg−1 (mean 32.11 μg kg−1 dw) and ND to 375.13 (mean 32.77 μg kg−1 dw), with detection frequencies of 37.3% and 38.1%, respectively. In biological samples, quinolones were the most frequently detected antibiotics (57.1–100%), with concentrations ranging from 286.6–1655.3 μg kg−1. The highest bioaccumulation factor (BAF) of 45407 L kg−1 was found for enrofloxacin. The phase distribution calculation showed that tetracyclines were the most strongly adsorbed antibiotics in the sediment, with the highest pseudo-partitioning coefficient values, ranging from 1299 to 1499 L kg−1. The geographical differences of antibiotic concentrations were largely due to anthropogenic activities and the sewage discharges from the local cities along the rivers.