Qifeng Li

Risk assessment and source identification of perfluoroalkyl acids in surface and ground water: spatial distribution around a mega-fluorochemical industrial park, China

Perfluoroalkyl acids (PFAAs) can be released to water bodies during manufacturing and application of PFAA-containing products. In this study, the contamination pattern, attenuation dynamics, sources, pathways, and risk zoning of PFAAs in surface and ground water was examined within a 10km radius from a mega-fluorochemical industrial park (FIP). Among 12 detected PFAAs, perfluorooctanoic acid (PFOA) dominated, followed by shorter-chained perfluoroalkyl carboxylic acids (PFCAs). PFAA-containing waste was discharged from the FIP, with levels reaching 1.86mg/L in the nearby rivers flowing to the Bohai sea together with up to 273μg/L in the local groundwater in the catchment. These levels constitute a human health risks for PFOA and other shorter-chained PFCAs within this location. The concentrations of ∑PFAAs in surface water strongly correlated with the local groundwater. The dominant pollution pathways of PFAAs included (i) discharge into surface water then to groundwater through seepage, and (ii) atmospheric deposition from the FIP, followed by infiltration to groundwater. As the distance increased from the source, PFAAs levels in groundwater showed a sharp initial decrease followed by a gentle decline. The contamination signal from the FIP site on PFAAs in groundwater existed within a radius of 4km, and at least 3km from the polluted Dongzhulong River. The major controlling factor in PFAA attenuation processes was likely to be dilution together with dispersion and adsorption to aquifer solids. The relative abundance of PFOA (C8) declined while those of shorter-chained PFCAs (C4-C6) increased during surface water seepage and further dispersion in groundwater.

Shifts in production of perfluoroalkyl acids affect emissions and concentrations in the environment of the Xiaoqing River Basin, China.

Perfluoroalkyl acids (PFAAs) have been widely used in surfactant applications, especially as processing acids for fluoropolymer production. This study provides an analysis of sources of certain PFAAs emitted from the intensive fluoropolymer facilities in the Xiaoqing River Basin of China. Concentrations of perfluorooctanoic acid (PFOA) as great as 0.97mg/L in surface water and 10.5μg/g dry weight in surface sediment have been detected near the effluent of one facility (F1) that produces polytetrafluoroethylene (PTFE) and other fluoropolymers with massive capacity. With the great emission of PFAAs to water in natural conditions, the log KOC values decreased for short-chain PFCAs. Mass loads of PFAAs indicated that emissions of PFAAs from other facilities or sources were much less than those from F1, which emitted 174kg/d of PFAAs including 159kg/d of PFOA to the rivers. Even though production and emissions of PFOA have been strictly controlled in other countries since 2006, production of PFOA as well as several other fluoropolymers that use PFOA as processing aids has been increasing at F1 in recent years. We recommended that production shift should be taken into consideration in PFOA elimination actions.

Are levels of perfluoroalkyl substances in soil related to urbanization in rapidly developing coastal areas in North China

Concentrations of 13 perfluoroalkyl substances (PFASs) were quantified in 79 surface soil samples from 17 coastal cities in three provinces and one municipality along the Bohai and Yellow Seas. The ∑PFASs concentrations ranged from less than limitation of quantification (LOQ) to 13.97 ng/g dry weight (dw), with a mean of 0.98 ng/g dw. The highest concentration was observed along the Xiaoqing River from Shandong province, followed by that from the Haihe River in Tianjin (10.62 ng/g dw). Among four regions, ∑PFASs concentrations decreased in the order of Tianjin, Shandong, Liaoning and Hebei, which was consistent with levels of urbanization. Fluorine chemical industries allocated in Shandong and Liaoning played important roles in terms of point emission and contamination of PFASs, dominated by perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Intensive anthropogenic activities involved in urbanization possibly resulted in increasing releases of PFASs from industrial and domestic sources.

Perfluoroalkyl acids (PFAAs) in indoor and outdoor dusts around a mega fluorochemical industrial park in China: Implications for human exposure

The manufacture of fluorochemicals can lead to high levels of perfluoroalkyl acids (PFAAs) contaminating the surrounding environment and consequently elevated exposure to the local residents. In this study, measurements of PFAAs associated with indoor and outdoor dusts around a mega fluorochemical industrial park (FIP) were made. Perfluorooctanoic acid (PFOA) and short-chain perfluoroalkyl carboxylic acids (C4-C7 PFCAs) were the predominant forms in all samples. The signature of the PFAAs in dusts in the local area matched that found within the FIP complex. The contamination plume in the local area could be linked to the prevailing wind direction starting from the FIP. The dust concentrations decreased exponentially with distance from the FIP (noticeably in the first 5km). PFAAs contamination could be detected at the furthest location, 20km away from the FIP. The concentrations of PFAAs were higher in indoor dust (73-13,500ng/g, median: 979ng/g) than those in outdoor dust (5-9495ng/g, median: 62ng/g) at every location. The highest estimated daily intake of PFOA via dust ingestion (26.0ng/kg·bw/day) was for toddlers (2-5years) living 2km away from the FIP, which is posing human health risk, though exposure remains within the provisional tolerable daily intake values.

Hexabromocyclododecanes (HBCDDs) in surface soils from coastal cities in North China: Correlation between diastereoisomer profiles and industrial activities.

Hexabromocyclododecane (HBCDD) is a brominated flame retardant with a wide range of industrial applications, although little is known about its patterns of spatial distribution in soils in relation to industrial emissions. This study has undertaken a large-scale investigation around an industrialized coastal area of China, exploring the concentrations, spatial distribution and diastereoisomer profiles of HBCDD in 188 surface soils from 21 coastal cities in North China. The detection frequency was 100% and concentrations of total HBCDD in the surface soils ranged from 0.123 to 363 ng g(-1) and averaged 7.20 ng g(-1), showing its ubiquitous existence at low levels. The spatial distribution of HBCDD exhibited a correlation with the location of known manufacturing facilities in Weifang, suggesting the production of HBCDD as major emission source. Diastereoisomer profiles varied in different cities. Diastereoisomer compositions in soils were compared with emissions from HBCDD industrial activities, and correlations were found between them, which has the potential for source identification. Although the contemporary concentrations of HBCDD in soils from the study were relatively low, HBCDD-containing products (expanded/extruded polystyrene insulation boards) would be a potential source after its service life, and attention needs to be paid to prioritizing large-scale waste management efforts.

Traditional and new POPs in environments along the Bohai and Yellow Seas: An overview of China and South Korea.

Rapid economic growth during the past two decades in the region surrounding the Bohai and Yellow Seas has resulted in severe pollution. Large amounts of monitoring data on persistent organic pollutants (POPs) in various environmental media have been accumulated, which allows us to conduct a fairly comprehensive assessment of the region around the Bohai and Yellow Seas to elucidate spatial patterns of pollution on a regional scale. This review summarized distributions of traditional and new POPs, including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and perfluoroalkyl substances (PFASs), in various environmental media. In general, due to their physico-chemical properties (poor solubility in water), OCPs and PCBs were mainly detected in sediments, PBDEs and HBCDs were mainly detected in sediments and soils. PFASs, which have greater solubility, were mainly detected in the hydrosphere. For conventional POPs, such as OCPs and PCBs, Bohai Bay and Haihe River in China, Gyeonggi Bay and Lake Sihwa in South Korea were found to be most polluted areas. While for new POPs, such as PBDEs, HBCDs and PFASs, some areas were heavily polluted due to local production and applications. Estuarine and coastal areas of the Bohai Sea were more severely contaminated by POPs than coastal regions of the Yellow Sea. Overall, the present review will guide identification of key areas for strengthening risk assessment of POPs and management practices.

Transport of Hexabromocyclododecane (HBCD) into the soil, water and sediment from a large producer in China

Hexabromocyclododecane (HBCD) is used as a flame retardant with extensive industrial applications, which is mainly produced at facilities on the coast of China. Radially distributed soil samples and equidistant paired water and sediment samples were taken around one of the biggest HBCD production enterprises to reflect its environmental behavior via air deposition and wastewater discharge of HBCD diastereoisomers (α-, β- and γ-HBCD). Worldwide high concentrations of HBCD (11,700ng/g in the soil, 5080ng/L in the water and 6740ng/g in the sediment) were detected in these environmental samples. Concentrations dropped by two orders of magnitude over several kilometers distance from the plant. The diastereoisomer pattern varied in the three environmental compartments examined, such that γ-HBCD was the predominant diastereoisomer in the soil and sediment whilst α- and γ-HBCD shared the predominance in the water. The mass inventories of HBCD in the local soil and sediment were estimated to be 5006kg and 30kg respectively, suggesting that soil was the major sink of HBCD in the production area. As for the soil, the environmental burdens in the areas with radiuses of 2, 4 and 6km were 3210, 3770 and 4590kg respectively.

Major threats of pollution and climate change to global coastal ecosystems and enhanced management for sustainability

Coastal zone is of great importance in the provision of various valuable ecosystem services. However, it is also sensitive and vulnerable to environmental changes due to high human populations and interactions between the land and ocean. Major threats of pollution from over enrichment of nutrients, increasing metals and persistent organic pollutants (POPs), and climate change have led to severe ecological degradation in the coastal zone, while few studies have focused on the combined impacts of pollution and climate change on the coastal ecosystems at the global level. A global overview of nutrients, metals, POPs, and major environmental changes due to climate change and their impacts on coastal ecosystems was carried out in this study. Coasts of the Eastern Atlantic and Western Pacific were hotspots of concentrations of several pollutants, and mostly affected by warming climate. These hotspots shared the same features of large populations, heavy industry and (semi-) closed sea. Estimation of coastal ocean capital, integrated management of land-ocean interaction in the coastal zone, enhancement of integrated global observation system, and coastal ecosystem-based management can play effective roles in promoting sustainable management of coastal marine ecosystems. Enhanced management from the perspective of mitigating pollution and climate change was proposed.

Tracing perfluoroalkyl substances (PFASs) in soils along the urbanizing coastal area of Bohai and Yellow Seas, China

With the shift of fluorine chemical industry from developed countries to China and increasing demand for fluorine chemical products, occurrence of perfluoroalkyl substances (PFASs) in production and application areas has attracted more attention. In this study, 153 soil samples were collected from 21 cities along the urbanizing coastal area of the Bohai and Yellow Seas. PFASs in this area were relatively higher, compared with other study areas. The concentrations ranged from 2.76 to 64.0 ng g-1, and those in most sites were between 2.76 and 13.9 ng g-1, with a predominance of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Among the 21 coastal cities, contaminations of PFASs in Zibo, Nantong and Binzhou were elevated, which was likely affected by local fluorine chemical plants, equipment manufacturing and chemical industry, respectively. The total emissions of PFOA and PFOS were similar, with amount of 4431 kg and 4335 kg, respectively. Atmospheric deposition was the largest source, accounting for 93.2% of total PFOA and 69.6% of PFOS, respectively. In addition, due to application of aqueous film-forming foams (AFFFs) and sulfluramid, disposal of sewage sludge and stacking of solid waste, emission of PFOA and PFOS to soil was 1617 kg, accounting for 9.29% of the whole China. In general, pollution in Jiangsu, Shandong and Tianjin was more serious than those in Liaoning and Hebei, which was consistent with industrialization level and size of industrial sectors emitting PFASs.

Are unintentionally produced polychlorinated biphenyls the main source of polychlorinated biphenyl occurrence in soils

The production of polychlorinated biphenyls (PCBs) has been banned globally for decades, but PCB concentrations in environmental media remain relatively high, especially in urban areas. Emissions estimates, studies of soil gradients between urban and rural areas, and quantitative identification of regional sources of PCBs in soils are necessary for understanding the environmental behavior of PCBs. In this study, regional PCB emissions were estimated at a resolution of 10 km × 10 km, and the spatial distribution of soil PCBs from urban to rural areas was studied along the Bohai and Yellow Sea regions. Compared with rural areas, mean PCB concentrations in urban soils (20.7 ng/g) were found to be higher, and concentrations decreased with distance from the city. Across both latitude and longitude directions, high PCB emissions in urban areas matched the distribution of total PCB concentrations in soils. The concentrations of the pollutants PCB28, PCB52, PCB101, PCB118, PCB138, PCB153, and PCB180 in soils originated from 5-year emissions, and accounted for 97%, 95%, 84%, 81%, 58%, 57%, and 27% of the total emissions, respectively. Unintentionally produced PCB (UP-PCB) emissions, which are mainly derived from cement (42%), pig iron (37%), crude steel (18%), and rolled steel (3%) industries, are the major contributors to PCBs in soils. Further identification of the sources and fates of PCBs requires a combination of field, laboratory, and modeling efforts.