Simulation and risk assessment of arsenic by Hydrus-3D and CalTOX in a typical brownfield site.

Accurate quantification of arsenic migration and accumulation in brownfield site is critical for environmental management and soil remediation. However, the researches simulating arsenic in brownfield site in China are limited due to sparse data and complex migration behaviors. In this study, we simulated historic arsenic contamination using Hydrus-3D in an abandoned brownfield site in Hebei, China, from 1972 to 2019. Atmospheric discharge, wastewater leakage, solid waste discharge and tank leakage were calculated according to the factory processes for model simulation. Based on the results of Hydrus-3D, we assessed health risk of arsenic in this site. The results showed that total arsenic input to the soil surface from 4 pathways was 24.6 tons, the solid waste discharge was the highest contributor. The accumulation process mainly occurred in the unsaturated zone due to clay and silty clay absorbed arsenic and thus slow down the migration process. While in the saturation zone, abundant groundwater promoted migration of arsenic, resulting in widespread distribution of contaminated area. The model results represented good performance between simulated and measured values. Sensitivity analysis indicated that adsorption constant and water conductivity were the most influential parameters. Heath risk assessment showed that arsenic contamination continues to threaten resident health.

Preparation of combined hydrogel solution that is suitable to control the emission of odor pollutants from brownfield site and its control effects.

Odor pollution caused by brownfield site has attracted increasing attention. However, to date, fewer suitable materials can be used to control the emission of odor pollutant from brownfield site during remediation. This study prepared a kind of combined hydrogel solution based on sodium alginate and carboxymethyl cellulose sodium (CHS-SC) and tested the possibility of its membrane in controlling the emission of three odor pollutants (trichloroethylene, dimethyl disulfide, and p-xylene) from polluted soil. Our results showed that CHS-SC membrane could effectively control the emission of three odor pollutants from polluted soil. Comparatively, CHS-SC membrane had higher control rates for three odor pollutants at high ambient temperature (32 °C), short storage time of CHS-SC (5 days, 25 °C), and low odor pollutant concentration (2 ml/kg soil) than at low ambient temperature (2 °C), long storage time of CHS-SC (10 d, 25 °C), and high odor pollutant concentration (4 ml/kg soil), respectively. CHS-SC membrane was degraded by 79.23% after 150 days in soil and slightly changed soil bacterial community, indicating that it had good biodegradability and environmental friendliness. In addition, CHS-SC cost was the lowest among the products with similar function. This study shows that CHS-SC is effective in short-timely controlling the emission of odor pollutants from brownfield site.

Evaluation and Potential Uses of Site Investigation Soil Contamination Data Submitted to Uk Local Government.

There has been considerable brownfield development in the UK since 2000 due to increasing demand for new housing, combined with local opposition to building on greenbelt land. To facilitate this, extensive site investigations have been carried out and the reports submitted to local government as part of the planning process. This research investigates whether this largely untapped resource of site investigation data can be used to improve understanding of potentially toxic elements (PTE) and persistent organic pollutants (POP) at a local scale. The PTE/POP data were extracted from 1707 soil samples across 120 brownfield sites in an urban/suburban region. The samples were analysed to determine the effect of site location, historical use and site age on PTE/POP concentrations. Box plots indicating statistical results together with GIS maps of PTE/POP sample data provided the optimal visualisation of results. The dataset was shown to be a valuable resource, although further exploitation would be enhanced by digitisation of the submitted data. The paper explores potential applications of this data, including background concentrations and anthropogenic enrichment factors for PTE/POP. The results were summarised in a table for the PTE/POP and a preliminary risk assessment process chart to inform developers/regulators on potential PTE/POP levels on brownfield sites on a local scale. This information could focus design and resources for developers for site investigations and risk assessments and improve planning and regulatory guidance. The lack of predictability in PTE/POP results across sites have emphasised the ongoing need for intrusive site investigation on new brownfield developments.

Groundwater contaminated with short-chain chlorinated paraffins and microbial responses.

The vertical migrations of toxic and persistent short-chain chlorinated paraffins (SCCPs) in soils as well as the microbial responses have been reported, however, there is a paucity of data on the resulting groundwater contamination. Here, we determined the concentration and congener profile of SCCPs in the groundwater beneath a production plant of chlorinated paraffins (CPs) and characterized the microbial community to explore their responses to SCCPs. Results showed that SCCPs ranged from not detected to 70.3 µg/L, with C13-CPs (11.2-65.8%) and Cl7-CPs (27.2-50.6%), in mass ratio, as the dominant groups. Similar to the distribution pattern in soils, SCCPs in groundwater were distributed in hotspot pattern. CP synthesis was the source of SCCPs in groundwater and the entire contamination plume significantly migrated downgradient, while there was an apparent hysteresis of C13-CP migration. Groundwater microbial community was likely shaped by both hydrogeological condition (pH and depth) and SCCPs. Specifically, the microbial community responded to the contamination by forming a co-occurrence network with "small world" feature, where Desulfobacca, Desulfomonile, Ferritrophicum, Methylomonas, Syntrophobacter, Syntrophorhabdus, Syntrophus, and Thermoanaerobaculum were the keystone taxa. Furthermore, the interrelations between bacterial taxa and SCCPs indicated that the microbial community might cooperate to achieve the dechlorination and mineralization of SCCPs through either anaerobic organohalide respiration mainly functioned by the keystone taxa, or cometabolic degradation processes functioned by Aquabacterium and Hydrogenophaga. Results of this study would provide a better understanding of the environmental behavior and ecological effects of SCCPs in groundwater systems.

Asbestos contamination on brownfield development sites in the UK.

The development of brownfield sites in the UK requires site investigation for contamination as part of the regulatory planning process. This site investigation includes the collection of soil samples that are analysed for asbestos contamination. This research project analyses this untapped resource of brownfield asbestos data, using site investigation data submitted to a local Borough Council, in Surrey, UK. Over 100 site investigation reports were collected. This paper presents the trends in asbestos testing from 2001 to 2019 and data on the location, concentration, form and type of asbestos found in this Borough. The rate of asbestos detection has increased significantly, reflecting improvements in asbestos measuring techniques, to a rate of 22% for all samples tested between 2016 and 2019. The concentrations of asbestos found were very low, with 74% of samples having concentrations below the limit of detection of the laboratory and were predominantly of fibrous form. A significant proportion of samples contained more carcinogenic amphibole type. Most of the asbestos was found in the top 1 m of Made Ground soil. Site history was found to be important with gas works having the highest asbestos detection rate, though a detection rate of 10% was found in soil samples on former residential sites. This information is important to inform and update risk assessment for site workers and site remediation in relation to asbestos. Hence based upon these results, a qualitative risk chart for asbestos is presented to provide guidance and in-sight into asbestos on brownfield sites for local authorities and developers.

Distributions of chlorinated paraffins and the effects on soil microbial community structure in a production plant brownfield site.

The distributions of chlorinated paraffins (CPs) in soils and their ecological effects attract much attention, while site-scale data are still scarce. In this study, a comprehensive investigation was performed to understand the CP distributions at a CP production plant brownfield site, as well as their effects on soil microbial community. Short-, medium- and long-chain CPs (SCCPs, MCCPs, LCCPs) were detected in most samples with total contents ranging ND-5,090, ND-6,670, and ND-1450 ng g-1 (dw), respectively. A CP-hotspot was observed 10 m beneath the synthesis workshop, indicating the downward migration of CPs. The consistence of soil SCCP congener profiles with commercial product CP-52 suggested the leakage of CP products as the contamination source. Besides CPs, petroleum hydrocarbons (PHC) contamination also occurred beneath the synthesis workshop. Soil microbial community composition and diversity were significantly influenced by SCCPs (p < 0.05) despite their lower contents compared to other concerned contaminants. Microbial network analysis indicated nonrandom co-occurrence patterns, with Acinetobacter, Brevibacterium, Corynebacterium, Microbacterium, Stenotrophomonas, and Variibacter as the keystone genera. Genera from the same module showed significant ecological links (p < 0.05) and were involved in the degradation of PHCs and chlorinated organic contaminants. This study provides the first phylogenetic look at the microbial communities in CP contaminated soils, indicating that the long-term exposure to CPs and PHCs may lead to microbial group assemblages with the potential for degradation.

Polycyclic aromatic hydrocarbons in the sediments of the Gulfs of Naples and Salerno, Southern Italy: Status, sources and ecological risk.

This study investigated the spatial distribution, potential sources, and toxic effects of polycyclic aromatic hydrocarbons (PAHs) in the sediments of the Gulfs of Naples and Salerno (NaSa Gulfs), Southern Italy. The investigation focused on the coastal sea sediments of the Bagnoli brownfield site within the Gulf of Naples. The ∑16PAHs in the sediments of the NaSa Gulfs outside of the Bagnoli brownfield site have concentrations that ranged from 9.58 to 15,818 µg/kg, with a geometric mean (Gmean) of 234 µg/kg. High-molecular weight PAHs (HMW PAHs) contributed to over 80% of the ∑16PAHs. The concentration of ∑16PAHs in the Gulf of Naples was twice as high as that in Salerno (768 µg/kg and 317 µg/kg, respectively), and the ∑16PAHs levels in the Bagnoli brownfield site exceeded that in the NaSa Gulfs by over three orders of magnitude. The molecular distributions of PAHs studies suggested biomass/coal combustion as their main sources. Based on the analysis of the toxic equivalent quantity and sediment quality guideline quotient, the contamination of PAHs in sediments may pose significant toxicity and biological risks to marine organisms.

Characterization and source apportionment of polycyclic aromatic hydrocarbons (pahs) in the sediments of gulf of Pozzuoli (Campania, Italy).

Most of the literature reports on the impact of the former Bagnoli brownfield on the pollution of Bagnoli Bay, embedded in the Gulf of Pozzuoli (GoP). Thus, we studied concentrations, types and sources of sixteen PAHs (EPA) in sediments at 22 sites along 5 transects covering the entire area of GoP. Outstanding levels of PAHs were found, varying from 7.1µgg-1 to 2.5 E+3µgg-1. Sediments collected at sites far away from Bagnoli were found to be polluted to a similar extent than those facing the brownfield site, with values>100µgg-1. Total PAHs levels in the sediments of GoP were higher by thirty-eleven thousand fold than those reported by other studies from various marine sites in the world. Transit axes of fine and very fine sands and diagnostic indexes revealed a common pyrolytic PAHs pollution spreading from the Bagnoli plant to all GoP.