The Massive Expansion and Spatial Transformation of Potentially Contaminated Land Across China in 1990–2020 Observed from Remote Sensing and Big-data

Identifying and monitoring the spatiotemporal patterns of potentially contaminated land(PCL) in China is a key concern of ecological governance. However, the dynamics of PCL’s expansion remain unclear nationwide. Integrating high-resolution remote sensing images, a land-use/cover change database, crawler data from websites, and other multisource data, we produced a new dataset of China’s PCL in 1990, 2000, 2010, and 2020 using data fusion technology. Then we analyzed the spatiotemporal patterns of China’s PCL from 1990 to 2020. Our study shows that the acquired vector dataset of China’s PCL is of high quality and reliability, with an overall accuracy of 93.21%. The area of China’s PCL has kept growing for the past 30 years, and the growth rate was especially rapid during2000–2010, 2.32 and 6.13 times as rapid as that during 1990–2000 and 2010–2020, respectively. PCL has also been trending toward higher aggregation over markedly enlarged areas and has transferred progressively from north and southeast of China to northwest and southwest of China and Qinghai-Tibet Plateau. The patterns of China’s PCL have been driven by the joint factors of policies, mineral resources, economy, and others, among which policies and the economy have contributed more prominently to the long-term transition.Our study promotes the access to high-quality spatial data of PCL to facilitate environmental governance of mine wastes, pollution and land management.

Abandoned Mine, Potential Home for the People： A Case Study of Jos Plateau Tin-Mining Region

This paper seeks to examine the JPTMR （Jos Plateau Tin-Mining Region） as an abandoned mine that provides land for housing by examining the impact of the tin-mining activities due to the presence of heavy metals and radioactive substances and analyzing the level and availability of these substances and their effects on human health and the built environment within JPTMR. Utilizing secondary data, which map out 10 different locations in the region, the paper highlights the level of radioactive substances （X-ray, beta-ray and gamma-ray） and presence of heavy metals in the environment. The results show that there are traces of X-ray, beta-ray and gamma-ray as well as the heavy metals such as Pb, As, Cu, Cr and Ni which exceeded the international standards. This is particularly significant as people use the contaminated soils as building materials for their homes as well as for farming and food production. The inhabitants of the area are often without any knowledge about the perils of the contaminated soils, water as well as air which is serious long-term human catastrophe. Drawing from international experience, the paper argues that it is possible to develop housing in former tin-mining areas but requires careful remediation and engagement by the public and private sector.

Detection of novel brominated flame retardants (NBFRs) in the urban soils of Melbourne, Australia

A range of brominated flame retardants(BFRs)have been incorporated into polymeric materials like plastics,electronic equipment,foams and textiles to prevent fires.The most common of these,polybrominated diphenyl ethers(PBDEs),have been subject to legislated bans and voluntary withdrawal by manufacturers in North America,Europe and Australia over the past decade due to long-range atmospheric transport,persistence in the environment,and toxicity.Evidence has shown that replacement novel brominated flame retardants(NBFRs)are released to the environment by the same mechanisms as PBDEs and share similar hazardous properties.The objective of the current research was to characterize soil contamination by NBFRs in the urban soils of Melbourne,Australia.A variety of industrial and nonindustrial land-uses were investigated with the secondary objective of determining likely point sources of pollution.Six NBFRs;pentabromotoluene(PBT),pentabromoethylbenzene(PBEB),hexabromobenzene(HBB),2-ethylhexyl-2,3,4,5-tetrabromobenzoate(EH-TBB),1,2-bis(2,4,6-tribromophenoxy)ethane(BTBPE)and decabromodiphenyl ethane(DBDPE)were measured in 30 soil samples using selective pressurized liquid extraction(S-PLE)and gas chromatography coupled to triple quadrupole mass spectrometry(GC-MS/MS).NBFRs were detected in 24/30 soil samples with S5NBFR concentrations ranging from nd-385 ng/g dw.HBB was the most frequently detected compound(14/30),while the highest concentrations were observed for DBDPE,followed by BTBPE.Electronic waste recycling and polymer manufacturing appear to be key contributors to NBFR soil contamination in the city of Melbourne.A significant positive correlation between S8PBDEs and S5NBFR soil concentrations was observed at waste disposal sites to suggest that both BFR classes are present in Melbourne's waste streams,while no association was determined among manufacturing sites.This research provides the first account of NBFRs in Australian soils and indicates that these emerging contaminants possess a similar potential to contaminate Melbourne soils as PBDEs.

An emerging market for groundwater remediation in China： Policies, statistics, and future outlook

There is a rapidly emerging and potentially huge market for the remediation of contaminated ground- water in China. The Chinese government published a Water Action Plan in April 2015, a Soil Action Plan in May 2016, and a draft Soil Pollution Prevention and Control Law in June 2017. All of these new policies and regulations put pressures on local governments and contaminated site owners, obliging them to conduct site investigation and to cleanup contaminated groundwater. The Chinese population in northern regions heavily depend on groundwater, with nearly 70% of water supply coming from aquifer sources in the Beijing-Tianjin-Hebei region. However, poor groundwater quality due to natural geochemical background and anthropogeic pollution is a serious concern, with poor or very poor quality water observed in nearly 80% of groundwater monitoring wells in 17 northern provinces. Shallow groundwater in many areas has been contaminated by toxic pollutants such as heavy metals and chlorinated organic compounds. There is an urgent need to better understand the situation and to conduct groundwater remediation at contaminated sites. The Chinese government is investing heavily in the research and development for groundwater remediation, which is expected to greatly add to the quality and quantity of groundwater remediation projects in the near future.

Effects of typhoon "KAI-TAK" on deep ocean ambient noise in the South China Sea

By investigating the effects on deep ocean ambient noise of typhoon ＂KAI-TAK＂ which passed the north area of the South China Sea,it is shown that the wind speed,the rainfall intensity and the long wave swell caused by typhoon affect the ocean ambient noise significantly.The correlation between the ocean ambient noise and the wind speed during the typhoon is much better than that in the non-typhoon period in the same Beaufort scale.Analysis of the correlation between the 415 h ocean ambient noise measured data and wind speed shows that,when the frequency is greater than 300 Hz,the correlation coefficient between the ocean ambient noise and the wind speed is greater than 0.5,achieving a moderate correlation;when the frequency is greater than 630 Hz,the correlation coefficient is between 0.8 and 0.9,achieving a high degree of correlation.The correlation between the ocean ambient noise and the wind speed is better than that between the ocean ambient noise and the significant wave height when the frequency is greater than 300 Hz.The correlation between the ocean ambient noise and the wind speed in infrasonic band from 10 Hz to 20 Hz is poor in the South China Sea,because the shipping is busy in this sea area and the ocean ambient noise is contaminated by the ship noise even during the typhoon.