Distribution of Phthalate Esters in Topsoil: a Case Study in the Yellow River Delta, China
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Environ Monit Assess (2013) 185:8489–8500 DOI 10.1007/s10661-013-3190-7 Distribution of phthalate esters in topsoil: a case study in the Yellow River Delta, China Yang Hongjun & Xie Wenjun & Liu Qing & Liu Jingtao & Yu Hongwen & Lu Zhaohua Received: 21 August 2012 /Accepted: 4 April 2013 /Published online: 24 April 2013 # The Author(s) 2013. This article is published with open access at Springerlink.com Abstract TheYellowRiverDelta(YRD)isatypical anthropogenic activities areas (such as the urbanization agricultural and petrochemical industrial area of China. and industrialization), and agriculture influence district, To assess the current status of phthalate esters (PAEs) of which mainly originated from construction waste, mu- soil residues, soil samples (0∼20 cm) (n=82) were col- nicipal sewage, agricultural waste and pesticide, lected in Bincheng District, at the geographic center of discarded plastic effusion and atmospheric depositions. the YRD. PAEs were detected in all topsoil samples Concentrations of PAEs were weakly positivity correlat- analyzed, which indicated that PAEs are ubiquitous en- ed with soil organic carbon content and pH, which vironmental contaminants. Concentrations of 11 PAEs suggested both of them can affect the distribution of are in the range of 0.794∼19.504 μgg−1,withanaverage PAEs. The concentration of di (2-ethylhexyl) phthalate value of 2.975 μgg−1. It was presented that PAEs pollu- and di-n-butyl phthalate dominated in the 11 PAEs, with tion in this area was weak and monotonously increasing the average values of 0.735 and 1.915 μgg−1, respec- along the rural–urban gradient. Higher concentrations tively, and accounted for 92.1 % of the whole PAEs’ were observed from roadsides (and/or gutters), densely concentrations. No significant differences of PAE conge- neric profiles were observed between our work and others previously reported, which is consistent with the use of similar commercial PAEs around the world. Y. Hongjun (*) : X. Wenjun : L. Qing : L. Jingtao : L. Zhaohua Keywords Phthalate esters . PTS . Rural–urban Shandong Key Laboratory of Eco-Environmental gradient . Yellow River Delta Science for the Yellow River Delta, Shandong Provincial Engineering and Technology Research Center for Wild Plant Resources Development and Application of Yellow River Delta, Binzhou University, Introduction 391, 5th Yellow River Road, Binzhou City 256603 Shandong Province, China e-mail: [email protected] Soil is an important reservoir for many persistent toxic substances (PTS), including polycyclic aromatic hydro- Y. Hongwen (*) carbons, polychlorinated biphenyls, phthalate esters Northeast Institute of Geography (PAEs), and so on. These PTS have been received and Agricultural Ecology, CAS, Changchun, People’s Republic of China worldwide attention due to their high resistance to deg- e-mail: [email protected] radation, high bioaccumulation, and having toxic prop- erties (He et al. 2011). L. Zhaohua PAEs have been widely used as plasticizers in poly- Institute of Restoration Ecology, China University of Mining and Technology, vinyl chloride, polyvinyl acetates, polyurethanes, and Beijing, People’s Republic of China cellulosics. As non-plasticizers, they are an important 8490 Environ Monit Assess (2013) 185:8489–8500 ingredient in flexible vinyl products, such as wiring and Materials and methods cabling, wall covering, and flooring. They could be used in vinyl blood bags and IV tubing used to help save lives Study area as well (Staples et al. 1997). Up to now, the global production is estimated to be several million tons and Bincheng District (Fig. 1) is in Binzhou City, located at will continue to increase. As a result, PAEs have become the center of the YRD, China, which covers about ubiquitous contaminants in various environmental com- 740 km2. The gross output values of agriculture and partment (Zeng et al. 2009;Cendrineetal.2009;Liuet petrochemical industry accounted for roughly 10 and al. 2010;Yuanetal.2010;Maraqaetal.2011;Bradley 30 % of the total output value, respectively. Soil in this and Smith 2011; Zhang et al. 2012). Elevated levels for area was derived from alluvial sediments of the Yellow PAEs are detected in different environmental matrices River and is classified as Aquic Inceptisols (CST 2001). (Fromme et al. 2002;Teiletal.2006;Zengetal.2008). Due to the teratogenicity, carcinogenicity, and mutage- Chemicals and materials nicity (Xu et al. 2008;Liaoetal.2010), both the Environmental Protection Agency (EPA) of the Eleven mono-PAE reference material, containing di- USA and the China State Environmental methyl phthalate (DMP), diethyl phthalate (DEP), di- Protection Administration have listed PAEs as en- n-propyl phthalate (DPRP), diisobutyl phthalate vironmental priority pollutants. Three phthalates (DiBP), di-n-butyl phthalate(DnBP), di-n-pentyl phthal- (diethyl, di-n-buthyl-, and di-n-octyl phthalate esters) ate (DnAP), di-n-hexyl phthalate (DnHP), benzyl butyl are also listed in the black list of China’s water priority phthalate(BBP), di (2-ethylhexyl) phthalate (DEHP), di- pollutants by China National Environmental Monitoring n-nonyl phthalate (DnNP), and di-n-octyl phthalate Center. (DnOP), were purchased from Dr. Ehrenstorfer The Yellow River Delta (between 117° 48′ and (Augsburg, Germany) and were used to prepare a mix- 119° 45′E and 36° 52′ and 38° 12′N), one of the largest ture solution of 1,000 μgmL−1. deltas in China and characterized with a temperate, Neutral silica gel (80–100 mesh) and alumina (100– semi-humid continental monsoon climate, is located in 200 mesh) were cleaned with methanol (MeOH), the northeast of Shandong Province on the southern dichloromethane (DCM), and n-hexane, respectively, bank of the Bohai Sea (Qi and Luo 2007; Liu and Qi using Soxhlet extractor for 72 h, activated at 180±1 2011). Recently, high-speed developing in economy and 250±1 °C for 12 h, and subsequently deactivated promoted this area to an important agricultural and with 3 % (w/w) of deionized water (extracted with petrochemical area. Cotton, corn, wheat, and vegeta- DCM/n-hexane), respectively. Anhydrous sodium sul- bles are major products for food source of the growing fate was baked at 450 °C for 4 h and stored in sealed city population (Midmore and Jansen 2003). glass jars. Filter paper was extracted with methanol, Nowadays, concerns have aroused on potential con- DCM, and n-hexane with Soxhlet extractor for 72 h tamination of textiles and foodstuff with toxic con- prior to use. To avoid contamination, no plastic equip- taminants (Midmore and Jansen 2003). Soil PAEs ment was used during sampling and processing. Water pollution in the region can be strongly influenced was filtered by Milli-Q and double distilled. All organic by agricultural operations, urbanization, and oil re- solvents used were of analytical grade and redistilled finery production (Kaisarevic et al. 2007;Khaiet with glass system. All the laboratory glass apparatus al. 2007). It is therefore necessary to evaluate the were soaked in K2Cr2O7 sulfuric acid solution for at current residues of PAEs in the region. However, least 12 h and rinsed with organic-free reagent water little is known about soil PTS contamination in the thoroughly and finally baked at 180 °C for 4 h. YDR (Chen et al. 2012;Wangetal.2011;Nieet al. 2010). The major purposes of this study were to Soil sampling and preparation investigate the concentrations, compositions, and distributions of 11 PAEs in the Bincheng District, Topsoil samples (0∼20 cm) (n=82) were collected from an area representative of the YRD, and discuss their urban, suburban, and rural areas in September 2009, using contamination profiles and possible sources of a stainless steel shovel. Sample location coordinates were PAEs. recorded with a handheld GPS receiver (Fig. 1). In the Environ Monit Assess (2013) 185:8489–8500 8491 Fig. 1 Map of soil sampling sites for PAEs analysis in Bincheng District rural and suburban areas, samples were mainly collected extraction time 1 min, purge 2 min, and static cycle (n=3) from farmland and woodland, and in the urban areas, 10 min. High-purity nitrogen was employed as the purge samples were collected from residential, commercial, gas. The extracts were separated and concentrated to and industrial land. Samples were put into solvent-rinsed around 1 mL using rotary evaporation, and then concen- brown glass bottles with a Teflon cap and stored frozen trated extracts were cleaned and fractionated on a 10-mm (−20 ° C) until analysis. Before extraction, soil samples i.d. 1:2 alumina/silica gel glass column packed, from the were freeze-dried and sieved to less than 2 mm. bottom to top, with neutral silica gel (12 cm), neutral alumina (6 cm), and anhydrous sodium sulfate (1 cm). Sample extraction and cleanup The concentrated extracts were added into the column and washed with 40 mL of hexane. Then, PAEs were eluted Extraction of 11 PAEs congeners was conducted based on with 40 mL mixed solvent of acetone/n-hexane (2:8, v/v). the method of Antoinette et al. (2009). Soil samples were The extracts were concentrated using rotary evaporator extracted with dichloromethane/acetone (1:1 v/v)usinga and reduced to1 mL under a stream of purified N2. speed extractor (E-916, Büshi). A 5-g dry sample was mixed with 10 g of sand and placed in a 20-mL extraction Instrumental analysis cell with a temperature and pressure of 110 °C. The pressures employed were 1,500 psi for each protocol. The extracted compounds were determined with an The extraction stages were preheated 5 min, static solvent Agilent 7890N gas chromatography coupled to an 8492 Environ Monit Assess (2013) 185:8489–8500 Agilent 5975 mass spectrometer (GC-MS) (Agilent vario EL III elemental analyzer (Germany). Soil pH Technologies, Avondale, PA, USA), operating in elec- was measured by pH meter with a soil/water ratio tron impact and selective ion monitoring modes, and a of 1:2.5.