Progress in the research on aquatic environmental nonpoint source pollution in China

In this paper, the authors reviewed the development process of China's research on aquatic environmental nonpoint pollution, and the situation of nonpoint source pollution in east China was also analyzed.

About Some Aspects of Use of Optical Sensors for Monitoring the Aquatic Environment

Multi-channel polarization optical technology is increasingly used for prompt monitoring of water systems.Optical devices during the assessment of water quality determine the intensity of light through the studied aquatic environment.Spectrophotometric devices measure the spectrum of weakening of light through the aquatic environment.Spectroellipsometric devices receive spectra in vertical and horizontal polarizations.The presented article develops an adaptive optical hardware and image system for monitoring water bodies.The system is combined.It consists of 2 parts:1)automated spectrophotometer-refractometer,and 2)adaptive spectroellipsometer.The system is equipped with a corresponding algorithmic and software,including algorithms for identifying spectral curves,databases and knowledge of spectral curves algorithms for solving reverse problems.The presented system is original since it differs from modern foreign systems by a new method of spectrophotometric and spectroellipsometric measurements,an original elemental base of polarization optics and a comprehensive mathematical approach to assessing the quality of a water body.There are no rotating polarization elements in the system.Therefore,this makes it possible to increase the signal-to-noise ratio and,as a result,improve measurement stability and simplify multichannel spectrophotometers and spectroellipsometers.The proposed system can be used in various water systems where it is necessary to assess water quality or identify the presence of a certain set of chemical elements.

Toxic effects of crude-oil-contaminated soil in aquatic environment on Carassius auratus and their hepatic antioxidant defense system

Under the indoor simulant conditions, toxic effects of crude-oil-contaminated soil which was put into aquatic environment on the young fishes Carassius auratus and their hepatic antioxidant system after a 20-d exposure were investigated. Results showed that the relationship between the mortality of C. auratus and the exposed doses could be divided into 3 phases： fishes exposed to the low dose groups （0.5-5.0 g/L） were dead due to the ingestion of crude-oil-contaminated soils in aquatic environment; at the medium dose groups （5.0-25.0 g/L） fishes were dead due to the penetration of toxic substances; at the high dose groups （25.0-50.0 g/L） fishes were dead due to environmental stress. The highest mortality and death speed were found in the 1.0 g/L dose group, and the death speed was sharply increased in the 50.0 g/L dose group in the late phase of exposure. The activities of superoxide dismutase （SOD）, catalase （CAT） and glutathione S-transferase （GST） and the content of malaondialdehyde （MDA） in the hepatic tissues of C. auratus were induced significantly. The activity of SOD was increased and then decreased. It was significantly inhibited in the 50.0 g/L dose group. The activity of CAT was highly induced, and restored to a level which is little more than the control when the exposed doses exceeded 10.0 g/L. The activity of GST was the most sensitive, it was significantly induced in all dose groups, and the highest elevation was up to 6 times in the 0.5 g/L dose group comparing with the control. The MDA content was significantly elevated in the 50.0 g/L dose group, and the changes of the MDA content were opposite with the changes of GST activity.

Study on the System of Aquatic Environmental Monitoring Methods in China

The development of Chinese system of aquatic environmental monitoring methods was summarized. The existing problem of the system of aquatic environmental monitoring methods was analyzed. At last, some suggestions were made on setting and implementing the system of aquat- ic environmental monitoring methods in China.

Assessment of the conventional molybdenum-blue and magnesium-induced coprecipitation procedures in phosphorus measurement in various aquatic environments

Phosphorus （P） is an essential nutrient utilized by all organisms for energy transport and growth. Both the conventional molybdenum-blue method and the magnesium-induced coprecipitation （MAGIC） procedures were applied for the measurement of dissolved inorganic phosphorus （DIP） and total dissolved phosphorus （TDP） in more than 840 water samples collected between 2003 and 2005, including seawater （the Huanghai Sea, the East China Sea, and the northern South China Sea）, water from rivers and estuaries （the Changjiang, the Huanghe, and the major rivers emptying into the Jiaozhou Bay）, groundwater （in the drainage basin surrounding the Jiaozhou Bay）, rain-water, and aquaculture water samples. The MAGIC method allows the investigation of phosphorus distributions and cycling for systems in which DIP is below the detection limits of conventional methods. Comparison between the two methods demonstrated that the concentrations obtained with both methods were significantly correlated. The differences of DIP and TDP concentrations measured with the two methods were higher when the concentrations of DIP and TDP were lower, implying the lower reproducibility at low concentrations. The concentration differences increase with the increase in the proportion of DOP in TDP, which indicates that the discrepancy of DIP concentrations measured with the two methods increases when the DOP concentration is high. The discrepancies indicated that the composition of P compounds differs depending on sample sources and water type; it would be useful to infer the presence of different phosphorus compound pools from differences between the two methods. This study indicates the potential presence of a pool of alkaline-labile compounds for samples from rainwater and rivers and estuaries surrounding the Jiaozhou Bay; the potential presence of acid-labile compounds that were adsorbed by Mg（OH）2 for samples from the Changjiang Estuary, Huanghai Sea, East China Sea, and groundwater; the potential presence of a substantial pool of acid-labile compounds that were not adsorbed by Mg（OH）2 for samples from the Huanghe Estuary, aquaculture water, the East China Sea algal bloom water, and the northern South China Sea.

Numerical simulation of stratified turbulent two-phase flow in aquatic environment

The two fluid model of stratified turbulent two phase flow in aquatic environment is developed in this paper. The motion of each phase is described by a unified multi fluid model in an Eulerian coordinate system. The laws of turbulent transportation for each phase, and the restriction of each other between the two phases are completely simulated. The complex two phase turbulence with strong buoyancy effects is selected to examine numerically. The extensive experimental data obtained in stratified flow are used here. Comparison of the results of numerical simulation with the experimental data is conducted. It has shown that the results of numerical simulation are satisfactory.

State Key Laboratory of Environmental Aquatic Chemistry (SKLEAC) is under construction

A new State Key Laboratory named Environmental Aquatic Chemistry is establishing in the Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. It asso-ciates with other three Iaboratories in universities to make up an Joint State Key Laboratory of Environmental Simulation and Pollution Control. They are supported by Chinese Government with the loan from World Bank for about 2.5 million US dollars and the same amount of RMB.

The impact of heavy metals on bacterial tolerance of antibiotic resistance and growth in the aquatic environment of Vietnam

Heavy metals may induce bacterial antibiotic resistance and affect their growth in the ecosystem.In this study,we aim to determine bacterial growth and antibiotic resistance in the pressure of heavy metals.Observed the changing morphology by gram staining was checked for bacterial toleration with heavy metal,developing of the colony form unit(CFU)was analysed bacterial kinetic growths and their biofilm formation.The disk diffusion test was used to perform bacterial susceptibility profiles with Ceftazidime(30μg),Ceftriaxone(30μg),Colistin sulfate(10μg),Meropenem or Imipenem(10μg),Ciprofloxacin(5μg)and Azithromycin(15μg)and the CLSI was applied for interpreting the data.The bacterial morphology remarkably changed from normal to short,round shape at a high concentration of heavy metals after 1 month.Their changing shape adapted to heavy metals by survival growing and resisted to Azithromycin,Ciprofloxacin,and Colistin without biofilm formation after 1 month,that was continued increasing after 2 months.The bacterial growth and antibiotic resistance were significant differences between provinces(P=0.01),type of bacterial species,and concentration of heavy metals.These results indicate that heavy metals are a crucial factor-driven for enhancing bacterial adaptation in pollution water resources and inducing their antimicrobial resistance in the aquatic environment.

Historical Evolution of Mariculture in China During Past 40 Years and Its Impacts on Eco-environment

The rapid development of mariculture in China in recent decades has satisfied people's demand of seafood, and has made a great contribution to economic development. However, mariculture has also caused some negative impacts on the eco-environment. By statistically analyzing national data(as well as data for four main provinces) regarding the mariculture area and cultivation species in China since reform and opening up, the historical evolution of mariculture during the past 40 years was analyzed, the driving factors related to policy, market and technology innovation were discussed, and the potential impacts of mariculture on the coastal eco-environment were also illustrated. The statistical results indicated that the maricultural area increased radically during the past 40 years, from 1979(116.47 × 10~3 ha) to 2012(2205.65 × 10~3 ha), with an increase of nearly 20-fold. Shandong Province represented the fastest-growing region, with an increase of 31-fold. Moreover, the cultivated species had gradually become diversified. Initially, shellfish and algae were major species, and then it developed to various species including fish, and currently shellfish and crustaceans were the major species. The development of mariculture was driven by government policies, market economy and technology innovation. Rapid development of mariculture also caused significantly adverse impacts on the eco-environment of the coastal regions. For example, the sea reclamation for mariculture decreased the area and function of coastal wetlands and the contaminants originating from mariculture destroyed the coastal aquatic environment. Fortunately, the implementation of ‘13 th Five-Year Fisheries Planning' is expected to help both improve the seafood quality and reduce the contamination in coastal aquatic environment. This current study will provide reference for management and structure adjustment of mariculture in the future.

Removing microplastics from aquatic environments:A critical review

As one of the typical emerging contaminants,microplastics exist widely in the environment because of their small size and recalcitrance,which has caused various ecological problems.This paper summarizes current adsorption and removal technologies of microplastics in typical aquatic environments,including natural freshwater,marine,drinking water treatment plants(DWTPs),and wastewater treatment plants(WWTPs),and includes abiotic and biotic degradation technologies as one of the removal technologies.Recently,numerous studies have shown that enrichment technologies have been widely used to remove microplastics in natural freshwater environments,DWTPs,and WWTPs.Efficient removal of microplastics via WWTPs is critical to reduce the release to the natural environment as a key connection point to prevent the transfer of microplastics from society to natural water systems.Photocatalytic technology has outstanding pre-degradation effects on microplastics,and the isolated microbial strains or enriched communities can degrade up to 50%or more of pre-processed microplastics.Thus,more research focusing on microplastic degradation could be carried out by combining physical and chemical pretreatment with subsequent microbial biodegradation.In addition,the current recovery technologies of microplastics are introduced in this review.This is incredibly challenging because of the small size and dispersibility of microplastics,and the related technologies still need further development.This paper will provide theoretical support and advice for preventing and controlling the ecological risks mediated by microplastics in the aquatic environment and share recommendations for future research on the removal and recovery of microplastics in various aquatic environments,including natural aquatic environments,DWTPs,and WWTPs.

A critical review of microplastics in aquatic ecosystems: Degradation mechanisms and removing strategies

Plastic waste discarded into aquatic environments gradually degrades into smaller fragments,known as microplastics(MPs),which range in size from 0.05 to 5 mm.The ubiquity of MPs poses a significant threat to aquatic ecosystems and,by extension,human health,as these particles are ingested by various marine organisms including zooplankton,crustaceans,and fish,eventually entering the human food chain.This contamination threatens the entire ecological balance,encompassing food safety and the health of aquatic systems.Consequently,developing effective MP removal technologies has emerged as a critical area of research.Here,we summarize the mechanisms and recently reported strategies for removing MPs from aquatic ecosystems.Strategies combining physical and chemical pretreatments with microbial degradation have shown promise in decomposing MPs.Microorganisms such as bacteria,fungi,algae,and specific enzymes are being leveraged in MP remediation efforts.Recent advancements have focused on innovative methods such as membrane bioreactors,synthetic biology,organosilane-based techniques,biofilm-mediated remediation,and nanomaterial-enabled strategies,with nano-enabled technologies demonstrating substantial potential to enhance MP removal efficiency.This review aims to stimulate further innovation in effective MP removal methods,promoting environmental and social well-being.

Pharmaceuticals and personal care products (PPCPs) in the freshwater aquatic environment

Pharmaceuticals and personal care products(PPCPs)are a unique group of emerging environmental contaminants,due to their inherent ability to induce physiological effects in human at low doses.An increasing number of studies has confirmed the presence of various PPCPs in different environmental compartments,which raises concerns about the potential adverse effects to humans and wildlife.Therefore,this article reviews the current state-of-knowledge on PPCPs in the freshwater aquatic environment.The environmental risk posed by these contaminants is evaluated in light of the persistence,bioaccumulation and toxicity criteria.Available literature on the sources,transport and degradation of PPCPs in the aquatic environment are evaluated,followed by a comprehensive review of the reported concentrations of different PPCP groups in the freshwater aquatic environment(water,sediment and biota)of the five continents.Finally,future perspectives for research on PPCPs in the freshwater aquatic environment are discussed in light of the identified research gaps in current knowledge.

Significance of adverse outcome pathways in biomarker-based environmental risk assessment in aquatic organisms

In environmental risk assessments（ERA）, biomarkers have been widely used as an early warning signal of environmental contamination. However, biomarker responses have limitation due to its low relevance to adverse outcomes（e.g., fluctuations in community structure, decreases in population size, and other similar ecobiologically relevant indicators of community structure and function）. To mitigate these limitations, the concept of adverse outcome pathways（AOPs） was developed. An AOP is an analytical, sequentially progressive pathway that links a molecular initiating event（MIE） to an adverse outcome. Recently, AOPs have been recognized as a potential informational tool by which the implications of molecular biomarkers in ERA can be better understood. To demonstrate the utility of AOPs in biomarker-based ERA, here we discuss a series of three different biological repercussions caused by exposure to benzo（a）pyrene（Ba P）, silver nanoparticles（Ag NPs）, and selenium（Se）. Using mainly aquatic invertebrates and selected vertebrates as model species, we focus on the development of the AOP concept. Aquatic organisms are suitable bioindicator species whose entire lifespans can be observed over a short period; moreover, these species can be studied on the molecular and population levels.Also, interspecific differences between aquatic organisms are important to consider in an AOP framework, since these differences are an integral part of the natural environment.The development of an environmental pollutant-mediated AOP may enable a better understanding of the effects of environmental pollutants in different scenarios in the diverse community of an ecosystem.

Pharmaceutical compounds in aquatic environment in China： locally screening and environmental risk assessment

An environmental risk assessment was performed for pharmaceutical compounds present in the aquatic environment of China. Predicted environmental concentration （PEC） of the compounds were calculated according to European Medicines Evaluation Agency （EMEA） guidelines. Available ecotoxicological data compromised by applying a very conservative assessment factor （AF） were employed to calculate the predicted noeffect concentration （PNEC）. The screening principle and the risk assessment were based on risk quotient （RQ）, which derived from the PEC and related PNEC values. PEC results indicated that all the compounds except sulfadimethoxine and levocamitine, should carry out phase II risk assessment in EMEA guideline. RQ values suggested that more than 36 pharmaceuticals may be imposed health threats to the aquatic environment; especially the antibiotic therapeutic class including amoxicillin, sulfasalazine, trimethoprim, oxytetracycline and erythromycin showed high RQ values. These substances with high RQ value （RQ≥ 1） were regarded as top- priority pharmaceuticals for control in the aquatic environment of China. However, the antibiotic substances which had low risk quotient （RQ 〈 1）, should be reassessed by its potentially induced resistance under low concentration in future.

Chemical Characterization of Lake Togbadji

The present study focused on the chemical characterization of the watercourse of the Togbadji Lake wildlife ranch. The methodological approach followed is as follows: Bibliography review, Sampling campaign. The results obtained were the subject of descriptive statistics, the two-sample Wilcoxon test to determine the impact of different localities on the abundance of microbiological contaminants, a Principal Component Analysis (PCA) with the software R version 3.5.0, in order to group the pollution parameters according to the different levels and sources of contamination. From our results, it is found that the respective average values in dry and rainy seasons for ammonium ions are 0.38 ± 0.16 mg/L and 0.22 ± 0.03 mg/L;for nitrite ions 0.20 ± 0.25 mg/L and 0.02 ± 0.01 mg/L;for nitrate ions 3.72 ± 2.52 mg/L and 7.84 ± 4.91 mg/L;for total Kjeldahl nitrogen 1.27 ± 1.44 mg/L and 1.19 ± 1.49 mg/L;for orthophosphate ions 0.20 ± 0.25 mg/L and 0.02 ± 0.01 mg/L;for total phosphorus 0.04 ± 0.01 mg/L and 0.11 ± 0.23 mg/L;the chemical oxygen demand 93.36 ± 61.73 mg/L of O2 and 89.93 ± 66.11 mg/L of O2 and the biochemical oxygen demand over 5 days 25.50 ± 18.22 mg/L of O2 and 37 ± 33.15 of O2. It emerged that the main sources of pollution in Lake Togbadji are runoff water, discharges of various wastewater from artisanal activities, livestock farming and open defecation.

Ethogram of Yangtze finless porpoise calves (Neophocaena phocaenoides asiaeorientalis)

Underwater behavioral patterns of one Yangtze finless porpoise （Neophocaena phocaenoides asiaeorientalis） calf in captivity and those performed on the water surface by two calves in semi-natural environment were focally followed and continuously recorded until one year postpartum to construct the ethogram. The results indicate that 1） the three calves could display diverse and active behavioral patterns; 2） soon after birth, patterns critical for survival appeared first; 3） playful and social patterns predominated the ethogram; 4） most of the patterns were alike across age classes; 5） most of the patterns appeared at the calves’ early life stage. It is possible that the above characteristics are adaptively shaped by the aquatic and social life of this subspecies.

Multifaceted Aquatic Environmental Differences between Nanoplastics and Microplastics:Behavior and Fate

Microplastics and nanoplastics are emerging pollutants of concern in the aquatic environment that are causing increasing global environmental and human health problems.Although there has been extensive research on microplastics and nanoplastics,little has been said about the differences in their behavior in the aquatic environment,and many studies have considered them as the same class of hazardous materials;but in fact,microplastics and nanoplastics should be considered as two different types of environmentally hazardous materials.In this review,we propose that microplastics and nanoplastics behave in the aquatic environment in a size-dependent manner and should be distinguished.And we systematically analyzed the differences in the behavior of microplastics and nanoplastics in the aquatic environment in terms of five aspects:1)distribution behavior;2)adsorption behavior;3)reaction with natural colloids;4)aging and leaching behavior;5)interaction with organisms.This paper has been written to draw academic attention to the different behaviors of microplastics and nanoplastics in the aquatic environment in order to distinguish between their effects on humans and the environment.

Analysis on Strategic Future of Application of Agricultural Ecological Source in Control on Agricultural Nonpoint Source Pollution in Xi River Area in Guangxi

Non-point source pollution has become a hot issue on aquatic ecological environment at home and abroad. The research analyzed the challenges confronted by Xi River and proposed to construct agricultural ecological source in middle and upper reaches of the Xi River from the perspectives of scientific layout, legal construction, routine monitoring, technology integration, and coordination system in order to promote sustainable development of eco-environment in Xi River.

Mercury in aquatic fauna contamination:A systematic review on its dynamics and potential health risks

Mercury is an important pollutant,released into aquatic ecosystems both naturally and by anthropogenic action.This element is transferred to aquatic organisms in different ways,causing potential health risks.In addition,mercury can be accumulated by humans,especially through the consumption of contaminated food.This systematic review aims to present mercury pathways,the major routes through which this element reaches the aquatic environment and its transformations until becoming available to living animals,leading to bioaccumulation and biomagnification phenomena.The key biotic and abiotic factors affecting such processes,the impact of mercury on animal and human health and the issue of seafood consumption as a source of chronic mercury contamination are also addressed.A total of 101 articles were retrieved from a standardized search on three databases(PubMed,Emabse,and Web of Science),in addition to 28 other studies not found on these databases but considered fundamental to this review(totaling 129 articles).Both biotic and abiotic factors display fundamental importance in mediating mercurial dynamics,i.e.,muscle tropism,and salinity,respectively.Consequently,mercurial contamination in aquatic environments affects animal health,especially the risk of extinction species and also on human health,with methylmercury the main mercury species responsible for acute and chronic symptomatology.

A continuing 30-year decline in water quality of Jiaojiang Estuary, China

A quantitative description of a long-term series of aquatic environmental factors and their spatial distributions was generated using measured data from the Jiaojiang Estuary from 1982 to 2011. The aquatic environmental factors included suspended matter, salinity, and nutrients. Based on these factors, the aquatic ecosystem health in the Jiaojiang Estuary over the last 30 years was analyzed. The results indicated that the suspended matter concentration in the estuary was mainly affected by the amounts of suspended sediment and solid waste, with the value fluctuating over a long period, and the range of high concentration expanded continually; the salinity was mainly affected by precipitation and surface water resources, showing an overall decreasing trend, and the region with low salinity moved seaward and toward the reclamation areas; and the nutritional status, mainly affected by discharge of industrial wastewater and domestic sewage, was satisfactory in the 1980s and 1990s, but the status became severe in recent years. Reclamation had a great influence on these three factors： high reclamation strength led to a significant increase in the suspended matter concentration and a deterioration of the nutritional status, and the reclamation rate was negatively related with the salinity in the estuary. There was a significant positive correlation between the health status of the aquatic ecosystem and salinity, with a correlation coefficient of 0.93. The correlation coefficient between the health status and nutritional status was -0.71, while the correlation between the suspended matter concentration and health status was not as significant as that of the other two factors. The dynamics of the aquatic environment could be divided into four stages： sustainable health from the 1980s to the 1990s, continued deterioration from 2000 to 2003, improvement from 2004 to 2005, and secondary deterioration from 2006 to 2011. The Jiaojiang Estuary is faced with imminent environmental pressure at present.