| Lake and reservoir(lake)play an important role in serving people’s livelihood and ensuring water security due to their rich water resources.However,rapid economic growth,demographic structure and climate change have degraded the water environment,and water quality is being challenged.The water environment security of lake has become the focus of attention.In order to understand the pollution status and treatment of global lakes,this paper is based on 1838 literatures on lake pollution and 196 literatures on lake control measures collected in Web of Science(WOS)database from 1970 to 2021.Meta-analysis and environmental risk assessment were used to clarify the pollution status and treatment of global lakes in the past 50 years.It provides basic data and scientific basis for ensuring safe water use and realizing the unification of economic,social and ecological benefits of water resources.The conclusions were:A total of 1,685 lakes in 97 countries were studied in 1,838 papers,covering more than300 types of pollutants,including various chemical elements and organic compounds.Pb and polycyclic aromatic hydrocarbons(PAHs)were the most frequently studied chemical elements and organic compounds,respectively.Pollutant study frequency showed that Pb,Cu,Zn,Cd,Cr,Ni,As and Hg,as well as PAHs,organochlorine pesticides(OCPs),polychlorinated biphenyls(PCBs),microplastics(MPs),polybrominated diphenyl ethers(PBDEs),antibiotics(ABs)were the main pollutants.Risk assessment of heavy metals based on Sediment Quality Guidelines(SQGs)and single factor pollution index showed that the ecological risk of Ni,Cr and As pollution in lake sediments were higher.Ni,Cr and As of Russia’s Lake Kuetsjarvi,India’s Ashtamudi Lake,and Serbia’s Gru Z Reservoir were seriously polluted.The pollution of Pb,As and Cd in water bodies was more serious,and the pollution of Pb,As and Cd in Lake Wielkie of Poland,Tangyung Co of China and Eleyele Lake of Nigeria were more serious.Analysis of individual organic pollutants showed that PAH in sediment and DDT in water were highly concentrated.The pollution of 16 priority PAHs in the sediments of Erhai Lake in China was serious,and DDTs in the water of Songkhla Lake in Thailand was serious.Among 34 lakes,58.82% were eutrophication,and26.47% were severe eutrophication.In global lake water,the average concentrations of total nitrogen(TN),total phosphorus(TP),chlorophyll a(Chl-a)were 2.19 mg/L,0.13 mg/L and70.34 μg/L.Three indicators were higher concentrations in Dianchi Lake in China,Krishnagiri Reservoir in India and Lake Tsukui in Japan.There were 36 different measures in 196 literatures on lake management measures.The results showed that all the measures improved the water transparency and total suspended solids by 95% and 87%,respectively.The best time period for water quality improvement was 0-5 years.The common treatment measures were in situ passivation,constructed wetland(CW),aeration,phytoremediation and biological regulation.However,there were great differences in the removal effects of each index.The removal rates of TP in water by the five measures were 62.92%,45.52%,59.37%,36.67% and 41.87%,and the removal rates of Chl-a were 58.55%,44.67%,-196.76%,71.56% and 33.66%,respectively.The removal rates of TN from water by passivation,CW,phytoremediation and biological regulation were 44.96%,56.57%,21.96% and 39.52%,respectively.For in-situ passivation,the treatment effect of mixed passivator was better than that of single passivator,and the best duration of passivation benefit was within 5 years after application.The combined type of CW improved the water quality better than the single type of CW.Based on meta-analysis,this study summarized and analyzed the research fields of lake pollution and treatment in the past 50 years,and provided important reference for lake pollution evaluation and treatment,which could help to solve the problem of lake pollution. |
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