Application of Big Data in the Remediation of Contaminated Sites

China has large population but little land.Such objective conditions determine that it is required to adhere to the policy path of"cherishing,rationally utilizing land and practically protecting cultivated land".Due to the relatively immature technology in the early stage of resource development in China,extensive utilization of resources leads to serious pollution,and the situation of the restoration of contaminated sites is severe.After nearly 20 years of a large number of pollution,land restoration there have been a lot of achievements in research and practice,but in the era of big data development,prevention and cure of soil pollution in China,there are a number of problems in the development of science and technology,this paper put forward the corresponding recommendations and opinions for the existing problems,in order to provide decision support for using big data to repair contaminated sites.

Experience in Remediation of Contaminated Sites at Home and Abroad

The selection of remediation technology for contaminated site is a key link of the remediation project.It determines the success or failure of the site remediation.The complexity of the types of contaminants in the site determines the diversity of remediation technologies.The experience of many countries in the world shows that the use of scientific and technological means and advanced technology can more effectively carry out the work of soil protection and pollution prevention and control,and achieve obvious results.

Monitoring dioxins and PCBs in eggs as sensitive indicators for environmental pollution and global contaminated sites and recommendations for reducing and controlling releases and exposure

This review compiles information on PCDD/F-and PCB-contaminated eggs from 20 years of global egg monitoring around emission sources in four continents conducted by the International Pollutants Elimination Network(IPEN)and Arnika as well as a compilation of data from scientific literature.IPEN monitored 127 pooled egg samples including samples from 113 chicken flocks at potential PCDD/F-and PCB-contaminated sites around priority sources listed in the Stockholm Convention(e.g.waste incinerators,metal industries,cement plants,and open burning).99(88%)of pooled egg samples were above the EU maximum limits for PCDD/Fs(2.5 pg PCDD/F-TEQ/g fat)or the sum of PCDD/Fs and dioxinlike PCBs(5 pg PCDD/F-PCB-TEQ/g fat).Children consuming such eggs exceed the tolerable weekly intake(TWI).This demonstrates that close to 90%of these areas were not safe for the production of free-range eggs.Sixteen out of the 113 egg samples(14%)were contaminated above 50 pg TEQ/g fat and exceeded the EU maximum limit more than 10 times.From the 26 pooled egg samples around incinerators 24(92%)exceeded the limit with a mean of 43.1 pg TEQ/g fat(2.6e234 pg TEQ/g).All 21 egg samples around metal industries(4.4e112.6 pg TEQ/g fat)were above limits with mean concentration of 26.0 pg TEQ/g fat.Also all 7 egg samples measured at e-waste recycling sites were above limits(mean 308 pg TEQ/g fat).In 58(51%)pooled egg samples the PCB-TEQ was above 5 pg TEQ/g fat exceeding the EU maximum limit with dioxin-like PCBs alone.This highlights the role of commercial PCBs for global contamination with dioxin-like compounds.It was discovered that around metal industries,shredder plants,open burning sites of e-waste and dump sites,a high share of contamination was caused by dl-PCBs.This clearly shows severe PCB release from the end-of-life management of PCB-containing equipment in developing countries.Also highly contaminated eggs were found at many sites where plastic was incinerated.The highest contaminated egg sample ever measured came from an e-waste site in Ghana and had 856 pg TEQ/g fat plus 300 pg TEQ from brominated dioxins(PBDD/Fs).Other extreme PCDD/F contaminations of eggs were found at a chlor-alkali site(514 pg TEQ/g fat),Agent Orange contaminated areas in Vietnam(490,249 and 246 pg TEQ/g fat)and e-waste sites(568 and 520 pg TEQ/g fat).Where DR CALUX®bioassay revealed higher TEQ compared to measured PCDD/F-PCB-TEQ in IPEN studies,polybrominated PBDD/F were also measured and detected up to 300 pg TEQ/g fat at e-waste sites.One positive outcome from the IPEN studies is that all 10 pooled supermarket eggs in developing countries were below regulatory limit.Policy recommendations are made including:a systematic assessment of areas around PCDD/Fs and PCBs sources;measures for reduction of exposures of populations;urgent control of emission sources including PCB equipment,the open burning of plastic,and the use of plastic as fuel in boilers/incinerators in developing countries without air pollution control.Furthermore,soil limits need to be re-assessed and lowered for free-range poultry.

Three-dimensional delineation of soil pollutants at contaminated sites: Progress and prospects

The precision remediation and redevelopment of contaminated sites are crucial issues for improving the human settlement and constructing a beautiful China. Three-dimensional delineation of soil pollutants at contaminated sites is a prerequisite for precision remediation and redevelopment. However, a contaminated site is a three-dimensional complex system coupling multiple spatial elements above-and under-ground. The complexity incurs high uncertainties about the three-dimensional delineation of soil pollutants based on sparse borehole and spatial statistics and inference models. This paper first systematically reviewed the objectives of fine three-dimensional delineation of soil pollutants, the sampling strategies for soil boring, the commonly used models for delineating soil pollutants, and the relevant cases of applying these models at contaminated sites. We then summarized the effects of borehole data and three-dimensional models on soil pollutants' delineation results from biased characteristics and nonstationary conditions. The present research status and related issues on correcting the biased characteristics and nonstationary conditions were analyzed. Finally, based on the problems and challenges, we suggested the three-dimensional delineation of soil pollutants in the underground “black box” for future research from the following six priority areas: multi-scenarios, nonstationary, non-linearity, multi-source data fusion, multiple model coupling, and the delineation of co-contaminated sites.

Phytoremediation of Contaminated Chemical Plant Sites

[Objective] The aim was to research phytoremediation effects on soils with combined pollution. [Method] With simulation experiment, the test selected plants suitable for phytoremediation in soils polluted with Pb-Cd, PAHs, and Pb-Cd-PAHs,respectively and ryegrass was grown to explore phytoremediation on contaminated sites by adjusting bio-availability. [Result] After 70 d growing of ryegrass, the content of available Pb in contaminated soils was 375.26 mg/kg, the content of Cd was 4.9mg/kg after 90 d, and the content of B [a]P was 0.60 mg/kg after 100 d, which were all lower compared with soil limits. [Conclusion] Ryegrass is a suitable plant for phytoremediation.

Preliminary Hydrogeologic Modeling and Optimal Monitoring Network Design for a Contaminated Abandoned Mine Site Area: Application of Developed Monitoring Network Design Software

In abandoned mine sites, i.e., mine sites where mining operations have ended, wide spread contaminations are often evident, but the potential sources and pathways of contamination especially through the subsurface, are difficult to identify due to inadequate and sparse geochemical measurements available. Therefore, it is essential to design and implement a planned monitoring net-work to obtain essential information required for establishing the potential contamination source locations, i.e., waste dumps, tailing dams, pits and possible pathways through the subsurface, and to design a remediation strategy for rehabilitation. This study presents an illustrative application of modeling the flow and transport processes and monitoring network design in a study area hydrogeologically resembling an abandoned mine site in Queensland, Australia. In this preliminary study, the contaminant transport process modeled does not incorporate the reactive geochemistry of the contaminants. The transport process is modeled considering a generic conservative contaminant for the illustrative purpose of showing the potential application of an optimal monitoring design methodology. This study aims to design optimal monitoring network to: 1) minimize the contaminant solute mass estimation error;2) locate the plume boundary;3) select the monitoring locations with (potentially) high concentrations. A linked simulation optimization based methodology is utilized for optimal monitoring network design. The methodology is applied utilizing a recently developed software package CARE-GWMND, developed at James Cook University for optimal monitoring network design. Given the complexity of the groundwater systems and the sparsity of pollutant concentration observation data from the field, this software is capable of simulating the groundwater flow and solute transport with spatial interpolation of data from a sparse set of available data, and it utilizes the optimization algorithm to determine optimum locations for implementing monitoring wells.

Managing international collaboration for the development and application of environmental technologies: opportunities for China & other Asia Pacific countries

Increased international cooperation in the field of contaminated site management has resulted in the formation of numerous networks and fora. The key benefits of increased co\|operation are perceived to be in the reduction of duplication in efforts, particularly related to industry, in the co\|ordination of contaminated site research, policy development and information dissemination. The paper introduces and briefly discusses key networks and collaborative projects currently in operation throughout the world relating to contaminated site management. The experience shared within these groups should prove useful to the application of such environmental problems in China and the Asia\|Pacific region.

Site Pollution Remediation and Its Technology

This paper summarized the connotation of contaminated site remediation,the differences between contaminated site and brownfield,the differences between contaminated site and soil pollution and land pollution,clarified the relationship between the concepts,and introduced the remediation technology of contaminated site.

Occurrence of dark septate endophytes in Phragmites australis in the Baiyang Lake and their resistance to Cd stress

Heavy metal pollution poses a serious hazard to human health,and microbial remediation of heavy metals in soil has been widely studied.A group of ascomycetes classified as dark septate endophytes(DSEs)colonize plant roots and benefit host plants under abiotic stress conditions.In this study,Phragmites australis,a common remediation plant in the Baiyang Lake in North China,was investigated.Soils and roots of P.australis were collected in typical heavy metal-contaminated sites,and the species diversity and community structure of DSEs in P.australis roots were studied.In addition,DSE strains were isolated,cultured,and tested for their tolerance to Cd stress.The results showed that DSEs occurred extensively in P.australis roots,forming typical dark septate hyphae,with a total colonization rate of 19.7%–83.1%.Morphological and internal transcribed spacer sequencing analyses were used to identify 10 species within 9 genera of DSE fungi.Among these fungi,6 strains with considerable resistance to Cd stress were identified.The biomasses of Poaceascoma helicoides,Alternaria doliconidium,and Acrocalymma vagum strains increased as the Cd levels increased.These results can not only help to understand plant-DSE interactions in wetland environments,but also provide a theoretical basis for making full use of DSE fungi to alleviate heavy metal contamination in soil.

Health Risks of Organic Contaminated Soil in an Out-of-Service Oil Refinery Site

Health risks assessment due to exposure to organic contaminated soil at an oil refinery out of service is conducted in this study by integrating health risk methods of U.S. EPA （United States Environmental Protection Agency）, ASTM （American Society for Testing and Materials） and VROM （Ministry of Housing, Spatial Planning and the Environment in Netherlands）, with the localized parameters using Chinese demographic characteristics and site features. The monitoring results show that the concentration of benzene, benzo（a）pyrene and benzo（a）anthracene in the soil of the site all exceed their risk screening values, respectively, with pollutants concentrated in soil 0.1-5.5 m beneath the surface. To estimate health risks of the site with the 95% upper confidence limit of the pollution, we focus on three major exposure pathways, namely, oral ingestion, dermal contact and breath inhalation, which indicates carcinogenic risk （CR） and non-carcinogenic hazard quotient （HQ） of the contaminated soil reach 9.59×10^-5 and 15.46, respectively, exceeding the acceptable level of 10^5 and 1, posing severe health hazards to the residents at the site. KEY WORDS： contaminated site, health risk, soil, organic contamination.

Treatability of volatile chlorinated hydrocarbon-contaminated soils of different textures along a vertical profile by mechanical soil aeration：A laboratory test

Mechanical soil aeration is a simple, effective, and low-cost soil remediation technology that is suitable for sites contaminated with volatile chlorinated hydrocarbons（VCHs）. Conventionally, this technique is used to treat the mixed soil of a site without considering the diversity and treatability of different soils within the site. A laboratory test was conducted to evaluate the effectiveness of mechanical soil aeration for remediating soils of different textures（silty,clayey, and sandy soils） along a vertical profile at an abandoned chloro-alkali chemical site in China. The collected soils were artificially contaminated with chloroform（TCM） and trichloroethylene（TCE）. Mechanical soil aeration was effective for remediating VCHs（removal efficiency 〉 98%）. The volatilization process was described by an exponential kinetic function.In the early stage of treatment（0–7 hr）, rapid contaminant volatilization followed a pseudofirst order kinetic model. VCH concentrations decreased to low levels and showed a tailing phenomenon with very slow contaminant release after 8 hr. Compared with silty and sandy soils, clayey soil has high organic-matter content, a large specific surface area, a high clay fraction, and a complex pore structure. These characteristics substantially influenced the removal process, making it less efficient, more time consuming, and consequently more expensive. Our findings provide a potential basis for optimizing soil remediation strategy in a cost-effective manner.

European cooperation to tackle the legacies of hexachlorocyclohexane(HCH)and lindane

Hexachlorocyclohexane(HCH)waste isomers from lindane production are the largest single POPs legacy,with an estimated 4.8 to 7.4 million tonnes of disposed waste.The largest part of this waste e 1.8 to 3 million tonnes e was disposed in Europe,where most producers were located.This paper provides a short overview of projects supported by the European Union(EU)to address this waste legacy and to implement the Stockholm Convention for this group of POPs with associated protection of soil,ecosystems and human health.We report here particularly on the results of a project financed by the EU called the“HCH in EU project”,which aimed to develop a systematic inventory of sites where HCH was handled and potentially resulted in contamination.The compiled information provide guidance for competent authorities to further assess their national HCH inventory and to further develop a strategy to address this large POP legacy in future.The systematic inventory revealed that there were at least 299 sites where HCH was handled.These sites include 54 former production sites,76 pesticide processing plants that used lindane,59 uncontrolled HCH waste isomer deposits,29 landfills with HCH waste,34 former or current storage sites for stocks of obsolete pesticides including technical HCH or lindane,and 16 HCH treatment or disposal sites.Additionally,at 31 of the sites lindane/technical HCH was used in applications with significant risk of soil pollution,such as wood treatment.The number of sites in this latter category is likely higher and will need further assessment.In addition to this inventory,the“HCH in EU project”produced detailed country reports,a guidance document for how to find potentially HCHimpacted sites,and a strategy document for implementing the sustainable management of these sites EU-wide,with proposed actions at the EU,country,and site level.Furthermore,the project has facilitated information exchange and e together with other related EU projects e has led to sharing information and best practices among member states and to establishing a network of authorities and other stakeholders working on the lindane/HCH waste legacy.This collaboration will facilitate a more systematic and better coordinated process to further assess,secure,and remediate the large HCH waste legacy and reduce and control lindane/HCH releases in the EU and possibly beyond.Such a coordinated effort and exchange of information for inventorying and managing contaminated sites might also be useful for other POPs such as PFOS/PFOA or dioxins.

Minimizing the environmental impact of PFAS by using specialized coagulants for the treatment of PFAS polluted waters and for the decontamination of firefighting equipment

Per-and polyfluoroalkyl substances(PFASs)represent an increasingly global challenge for keeping water and soil“non-toxic”.100 of millions of people are exposed to PFAS levels of concern,in particular,around PFAS production sites and sites where PFASs are/were used and released or disposed.The Stockholm Convention established recommendations to systematically assess PFOS pollution which can be transposed to all PFASs considering that PFASs are an issue of concern under The Strategic Approach to International Chemical Management(SAICM).One major wide-spread source of environmental pollution is the long-term use of PFAS-containing fire extinguishing agents.Strategies for the reduction of human exposure need to reduce and were feasible eliminate the current uses of PFASs and reduce and eliminate the human exposure from the contamination of the environment from past uses including contaminated drinking water.The current study shows that well-known methods of water treatment,especially the use of materials for adsorption and ion exchange,can often neither guarantee satisfactory cleaning results nor economically justifiable filter running times at high PFAS concentrations and complex matrix conditions.Their combination with a pre-precipitation stage using specialized precipitants can significantly optimize treatment successes.PFAS is still being released into the environment in considerable quantities by e.g.the use of so-called aqueous film forming foams(AFFF).Fire departments are increasingly trying to reduce the risks associated with the use of AFFF agents for the health of firefighting personnel and the environment by replacing AFFF foaming agents with fluorine-free foaming agents.If the fluorine-containing foaming agents are simply replaced,considerable residual PFAS loads often remain in the fire extinguishing systems contaminated with PFAS(fire engines,fire boats,stationary fire extinguishing systems,etc.),which are then discharged further into the environment during renewed operations-normally at a reduced concentration.The current study demonstrate that a conscientious decontamination of systems previously in contact with PFAS is therefore urgently required.Here,too,precipitants specialized for PFAS adsorption can make an important contribution to protecting the environment.Sites were firefighting equipment has been cleaned over years can also be considered contaminated and need assessment and possibly remediation.

Inventory and action plan for PFOS and related substances in Suriname as basis for Stockholm Convention implementation

Within the framework of the Stockholm Convention implementation in Suriname,the first inventory of perfluorooctane sulfonic acid(PFOS)has been developed.The major stocks of PFOS are firefighting foams with minor stocks in pesticides(ant baits)and possibly carpets.The inventory of firefighting foams assessed the import,current stocks and major use sites and recent releases.Considerable amount of PFOS and potentially PFOS containing firefighting foams are stored at the military base,the oil company and small firefighting departments throughout the country.The total amount of stored PFAS firefighting foam in Suriname is estimated to be at least 275.6 tonnes,where the major stockpile of 206 tonnes is at the oil storage facilities.For some of these foams PFOS content is confirmed and for others it is not clear if the foam contains PFOS or other per-or polyfluorinated alkylated substances(PFAS).The upper estimate of PFOS content is 4133 kg in these foams.Additionally,PFOS or other PFAS has also been discovered in fire extinguishers in institutions.The total amount of PFOS related substance EtFOSA imported with the pesticide sulfluramid was 75 kg.The imports were banned in 2014 and is controlled.A considerable amount of synthetic carpets are in stores even produced before 2003 where main use of PFOS from 3 M took place possibly containing PFOS related substances.A compilation of potentially PFOS contaminated sites has been made.Potentially contaminated sites result from firefighting foam use,dumpsites and sulfluramid use.The airport where firefighting foam was applied is above a major drinking water reservoir,where an urgent assessment is needed.Due to the lack of analytical capacity for PFOS and precursors,drinking water,firefighting foam or impacted carpets,could not been analysed.An action plan for the control of PFOS and other PFAS has been developed considering the synergy of the Stockholm Convention and the Strategic Approach to International Chemicals Management(SAICM)addressing this emerging pollution issue for developing countries.

Feasibility of Tea Saponin-Enhanced Soil Washing in a Soybean Oil-Water Solvent System to Extract PAHs/Cd/Ni Efficiently from a Coking Plant Site

Mixed contaminated brownfield sites have brought serious risks to human health and environmental safety. With the purpose of removing polycyclic aromatic hydrocarbons （PAHs） and heavy metals from a coking plant site, an innovative technology for ex-situ washing was developed in the present work. The combination of 15.0 mLL-1 soybean oil and 7.5 g L-1 tea saponin proved an effective method to extract co-pollutants from soil. After two consecutive washing cycles, the efficiency rates of removal for 3-, 4-, 5（＋6）-ring, and total PAHs, Cd, and Ni were approximately 98.2%, 96.4%, 92.3%, 96.3%, 94.1%, and 89.4%, respectively. Meanwhile, as evaluated by Tenax extraction method and metal stability indices, the residual PAHs and heavy metals after consecutive washing mainly existed in the form with extremely low bioaccessibility in the soil. Thus, in the soil after two washing cycles, there appeared limited environmental transfer risk of co-pollutants. Moreover, a subsequent precipitation method with alkaline solution and PAH- degrading strain Sphingobium sp. PHE9 inoculation effectively removed 84.6%-100% of Cd, 82.5%-91.7% of Ni, and 92.6%-98.4% of PAHs from the first and second washing solvents. The recovered solvents also exhibited a high recycling effectiveness. Therefore, the combined cleanup strategy proposed in this study proved environmentally friendly, which also played a major role in risk assessment and marlagement in mixed polluted sites.

Groundwater contamination and natural attenuation capacity at a petroleum spilled facility in Korea

As a remedial option, the natural attenuation capacity of a petroleum contaminated groundwater at a military facility was examined. Hydrogeological conditions, such as high water level, permeable uppermost layer and frequent heavy rainfall, were favorable to natural attenuation at this site. The changes in the concentrations of electron acceptors and donors, as well as the relevant hydrochemical conditions, indicated the occurrence of aerobic respiration, denitrification, iron reduction, manganese reduction and sulfate reduction. The calculated BTEX expressed biodegradation capacity ranged between 20.52 and 33.67 mg/L, which appeared effective for the reduction of the contaminants levels. The contribution of each electron accepting process to the total biodegradation was in the order： denitrification 〉 iron reduction 〉 sulfate reduction 〉 aerobic respiration 〉 manganese reduction. The BTEX and benzene point attenuation rates were 0.0058-0.0064 and 0.0005-0.0032 day-1, respectively, and the remediation time was 0.7-1.2 and 2.5-30 years, respectively. The BTEX and benzene bulk attenuation rates were 8.69 × 10^-4 and 1.05 × 10^-3 day-l, respectively, and the remediation times for BTEX and benzene were 7.2 and 17.5 years, respectively. However, most of the natural attenuation occurring in this site can be attributed to dilution and dispersion. Consequently, the biodegradation and natural attenuation capacities were good enough to lower the contaminants levels, but their rates appeared to be insufficient to reach the remediation goal within a reasonable time frame. Therefore, some active remedial measures would be required.

Ecology of industrial pollution in China

Industrial development has brought China both opportunities and challenges since the reform and opening up in 1978.Spatial and temporal analysis showed that rapid industrialization has made eastern China under a more serious pollution stress.The most serious effects of industrial pollution were reflected in aquatic and soil ecosystem degradation,and damage can be observed from species,population,and community to ecosystem level.Public consciousness about contaminated sites rose from 2004 leading to greater efforts in ecological remediation,monitoring,and risk governance.Considerable efforts are still needed in expanding the extent and breadth of monitoring to explore where the greatest ecological risks lie and how to control them.Ecology of industrial pollution has become a popular discipline in China and will be further developed to help achieve the Sustainable Development Goals.Future research for a better ecological risk management should be focused on multi-media transfer and effects of mixed pollutants,mechanisms for clean energy and material flow,and integration of ecological risk with human health risk.

Impacts of n-alkane concentration on soil bacterial community structure and alkane monooxygenase genes abundance during bioremediation processes

Petroleum hydrocarbons,mainly consisting of n-alkanes and polycyclic aromatic hydrocarbons(PAHs),are considered as priority pollutants and biohazards in the environment,eventually affecting the ecosystem and human health.Though many previous studies have investigated the change of bacterial community and alkane degraders during the degradation of petroleum hydrocarbons,there is still lack of understanding on the impacts of soil alkane contamination level.In the present study,microcosms with different n-alkane contamination(1%,3%and 5%)were set up and our results indicated a complete alkane degradation after 30 and 50 days in 1%-and 3%-alkane treatments,respectively.In all the treatments,alkanes with medium-chain length(C_(11)-C_(14))were preferentially degraded by soil microbes,followed by C27-alkane in 3%and 5%treatments.Alkane contamination level slightly altered soil bacterial community,and the main change was the presence and abundance of dominant alkane degraders.Thermogemmatisporaceae,Gemmataceae and Thermodesulfovibrionaceae were highly related to the degradation of C_(14)-and C_(27)-alkanes in 5%treatment,but linked to alkanes with medium-chain(C11-C18)in 1%treatment and C21-alkane in 3%treatment,respectively.Additionally,we compared the abundance of three alkane-monooxygenase genes,e.g.,alk_A,alk_P and alk_R.The abundance of alk_R gene was highest in soils,and alk_P gene was more correlated with alkane degradation efficiency,especially in 5%treatment.Our results suggested that alkane contamination level showed non-negligible effects on soil bacterial communities to some extents,and particularly shaped alkane degraders and degrading genes significantly.This study provides a better understanding on the response of alkane degraders and bacterial communities to soil alkane concentrations,which affects their biodegradation process.

A barrier to metal movement: Synchrotron study of iron plaque on roots of wetland plants

A wetland with attractive plants hosting birds and other wildlife is an esthetically pleasing prospect that is gaining popularity as a way of stabilizing or remediating metalcontaminated soils and sediment（Weber and Gagnon,2014;