Polychlorinated biphenyls in apple snails from an abandoned e-waste recycling site, 2010–2016: A temporal snapshot after the regulatory efforts and the bioaccumulation characteristics

https://doi.org/10.1016/j.scitotenv.2018.09.074Get rights and content

Highlights

  • PCBs in apple snails from the abandoned e-waste site decreased during 2010–2016.

  • The contribution of lighter PCB congeners increased over the years.

  • Theoretical BSAFs could predict the bioaccumulation of PCBs in apple snails.

  • Apple snail is a suitable bioindicator for PCBs in paddy field soils.

Abstract

The rudimentary recycling of electronic waste (e-waste) has been banned in China since the late 2000s, leaving many abandoned e-waste sites. However, knowledge is limited on the concentrations and fates of the e-waste derived contaminants such as polychlorinated biphenyls (PCBs) in these abandoned sites. In this work, we assessed the temporal trend of PCB concentrations in the year 2010, 2012, and 2016 at an abandoned e-waste site in South China, using apple snail as a bioindicator. The mean ∑PCBs concentrations in apple snails sampled in 2016 (53.2 ng/g dry weight) was approximately 11-fold higher than that (4.68 ng/g dry weight) in apple snails from a reference site. The result suggested that the abandoned e-waste recycling site was still heavily polluted by PCBs, despite of the fact that crude e-waste recycling processes have been prohibited for nearly 10 years. The concentrations of ∑PCBs were significantly decreased in 2016 compared to those in 2010 (mean: 115 ng/g dry weight) and 2012 (mean: 92.3 ng/g dry weight), but there were no significant differences in the concentrations between 2010 and 2012. Regarding the congener profiles, the contributions of lower chlorinated congeners (tri- and tetra-PCBs) in the snails tended to be higher over the years. The ∑PCBs in snails were significantly correlated with those in soils. Additionally, PCB profiles in snails resembled those in soils. These results suggested that apple snails can be used as an ideal bioindicator for PCBs in the paddy soils. Field determined biota-soil accumulation factors (BSAFs) for PCBs ranged from 0.31 to 1.9, with most of the values being 1–2; indicating that theoretical BSAFs can be used to predict the bioaccumulation of PCBs in the snails with a reasonable degree of certainty.

Introduction

Polychlorinated biphenyls (PCBs) are a class of chlorinated aromatic compounds in which one to ten chlorine atoms are attached to a biphenyl skeleton. Since the initial production of commercial PCBs in 1929, they had been extensively used for industrial purposes due to their highly chemical and thermal stability (Erickson, 2001). They were widely utilized as dielectric fluids in transformers, capacitor sand voltage regulators, and as plasticizers, lubricants, inks and surface coatings in carbonless copy paper (Erickson, 2001). These chemicals can be released to the environment during their production and the disposal of PCB-containing products. Because of their persistence, bioaccumulation potential and highly toxic effects, commercial PCB production ended in the USA, Western Europe and China during the 1970s (Erickson, 2001; Zhao et al., 2017), and worldwide formulation and application of PCBs was prohibited after the Stockholm Convention on persistent organic pollutants (POPs) in 2001 (UNEP, 2001). Despite the ban on the production and usages of PCBs, they continue to be of great concern because they can be emitted from fundamental sources such as old electrical and electronic products, and re-emitted from environmental reservoirs including soils, sediments, and other contaminated compartments (Breivik et al., 2007, Breivik et al., 2016; Zhao et al., 2017; Bogdal et al., 2014; Shanahan et al., 2015; Yadav et al., 2017; Li et al., 2018).

The primitive electronic waste (e-waste) recycling activities have caused heavy pollution of PCBs and other contaminants in developing countries such as China, India and Pakistan and some African countries (Wong et al., 2007; Chen et al., 2014; Iqbal et al., 2015). To deal with the worsening environmental problems in e-waste recycling sites, the Chinese local government has banned some crude processes of e-waste recycling such as open burning and acid washing since the late 2000s, leaving many abandoned e-waste sites in fields (Fu et al., 2012; Zhang et al., 2014; Wu et al., 2015; Wang et al., 2016). The local government also took some measures, e.g., covering the burning sites with uncontaminated soil, to control the re-emission of the pollutants (Wang et al., 2016). Despite of these efforts, extremely high levels of e-waste related contaminants were detected in the environment of the abandoned sites without further e-waste disposal and can still pose ecological risks (Zhang et al., 2014; Wu et al., 2015; Wang et al., 2016, Wang et al., 2017; Huang et al., 2018).

Apple snails (Pomacea canaliculata) are freshwater snails that naturally occur throughout the tropics and subtropics. They inhabit a wide range of ecosystems including natural streams, ponds, paddy fields and other waterways. Apple snails have a broad diet, preferring plant materials and decomposing organic matter (Kwong et al., 2010). Paddy fields constitute a more favorable habitat for apple snails than other ecosystems because of similarities in the environmental conditions (e.g., temperature, salinity, pH and flow velocity of paddy water) necessary for both rice production and for snail survival and development (Horgan, 2018). The ecology and biology of apple snail fit in with most of the essential characteristics of an ideal bioindicator, that is, bioaccumulation potential, wide distribution, narrow range of movement, short life-span, and ease in collection (Tanabe and Subramanian, 2006). These advantages make apple snail inhabited paddy field a suitable bioindicator for PCBs and other organic chemicals (Fu et al., 2011; She et al., 2013; Yuan et al., 2017).

Biomonitoring of PCB concentrations in abandoned e-waste recycling sites could provide information on PCB trends now that crude e-waste recycling activities have been banned. In this work, we present data from an abandoned e-waste recycling site in South China, using apple snail as a bioindicator. We collected the samples in 2010, 2012 and 2016 to evaluate whether PCB levels have continued to decrease following the stricter environmental regulations. Furthermore, we examined PCB levels in paddy soils and estimated the biota-soil accumulation factors (BSAFs) for these chemicals, to assess the bioaccumulation characteristics of PCBs in apple snails from the abandoned e-waste recycling site.

Section snippets

Sampling strategy

Apple snails (Pomacea canaliculata) were collected from 15, 16 and 11 adjacent paddy fields of an abandoned e-waste recycling site in South China (latitude 23°34′ N and longitude 113°01′ E), in April of 2010, 2012 and 2016, respectively. Apple snails collected from one paddy field were mixed as a pool sample which was composed of at least 20 individuals. The apple snails sampled for each year possess similar body length (3.0 ± 0.2 cm; mean ± SE). In the 2016 sampling, paddy soils (n = 11) were

Concentrations and congener profiles of PCBs

The concentrations of individual PCB congeners as well as the sum of the 28 PCBs detected (∑28PCBs) and the sum of the 7 marker-PCBs (∑7PCBs, including CBs 28, 52, 101, 118, 138, 153 and 180) in apple snails sampled in 2010, 2012 and 2016 are shown in Table 1. The concentrations of the ∑28PCBs in apple snails were 115 ± 15 (mean ± SE), 92 ± 11, and 53 ± 4.6 ng/g dry weight in the 2010, 2012, and 2016 sampling year, respectively. Previous studies have reported PCB concentrations in apple snails

Conclusions

The present study provides the recent levels and temporal trend of PCBs in apple snails living in paddy field of an abandoned e-waste recycling site in South China, a PCB hotspot with scarce dataset. Our results indicated that PCB levels have continued to decline over the period 2010–2016. However, recent PCB levels in the apple snails were still at significantly high levels, possibly resulting from the slow clean-up of these compounds without amended controls as well as fresh PCB input. The

Acknowledgements

Dr. Ying Zhang from the Pearl River Water Environment Monitoring Center is kindly acknowledged for assisting in instrumental analysis of part of the samples. This work was financially supported by the National Natural Science Foundation of China (grant 41373105), the Scientific Research Foundation of Anhui Normal University (grant 2017XJJ39), and State Key Laboratory of Organic Geochemistry, GIGCAS (grant SKLOG-201714). B.-X. Mai acknowledges the Local Innovative and Research Teams Project of

References (46)

  • Y.Z. She et al.

    Bioaccumulation of polybrominated diphenyl ethers and several alternative halogenated flame retardants in a small herbivorous food chain

    Environ. Pollut.

    (2013)
  • E. Terzaghi et al.

    Rhixzoremediatin half-lives of PCBs: role of congener composition, organic carbon forms, bioavailiability, microbial activity, plant species and soil conditions, on the prediction of fate and persistence in soil

    Sci. Total Environ.

    (2018)
  • Y. Wang et al.

    Factors influencing the atmospheric concentrations of PCBs at an abandoned e-waste recycling site in South China

    Sci. Total Environ.

    (2017)
  • S. Wen et al.

    Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) monitored by tree bark in an e-waste recycling area

    Chemosphere

    (2009)
  • M.H. Wong et al.

    Export of toxic chemicals – a review of the case of uncontrolled electronic-waste recycling

    Environ. Pollut.

    (2007)
  • J.P. Wu et al.

    Bioaccumulation of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in wild aquatic species from an electronic waste (e-waste) recycling site in South China

    Environ. Int.

    (2008)
  • J.P. Wu et al.

    Biomagnification of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls in a highly contaminated freshwater food web from South China

    Environ. Pollut.

    (2009)
  • Q. Wu et al.

    Heavy metal contamination of soil and water in the vicinity of an abandoned e-waste recycling site: implications for dissemination of heavy metals

    Sci. Total Environ.

    (2015)
  • I.C. Yadav et al.

    Possible emissions of POPs in plain and hilly areas of Nepal: implications for source apportionment and health risk assessment

    Environ. Pollut.

    (2017)
  • B. Yuan et al.

    Short-chain chlorinated paraffins in soil, paddy seeds (Oryza sativa) and snails (Ampullariidae) in an e-waste dismantling area in China: homologue group pattern, spatial distribution and risk assessment

    Environ. Pollut.

    (2017)
  • Y. Zhang et al.

    Biota-sediment accumulation factors for Dechlorane Plus in bottom fish from an electronic waste recycling site, South China

    Environ. Int.

    (2011)
  • J. Zhang et al.

    Risk assessment of polychlorinated biphenyls and heavy metals in soils of an abandoned e-waste site in China

    Environ. Pollut.

    (2014)
  • Y. Zhang et al.

    Bioaccumulation and translocation of polyhalogenated compounds in rice (Oryza sativa L.) planted in paddy soil collected from an electronic waste recycling site, South China

    Chemosphere

    (2015)
  • Cited by (21)

    • Fate and toxicity of legacy and novel brominated flame retardants in a sediment-water-clam system: Bioaccumulation, elimination, biotransformation and structural damage

      2022, Science of the Total Environment
      Citation Excerpt :

      Compounds with lower Kow were more bioavailable because it was easier to dissolve into water and be absorbed by clams, and could often be eliminated rapidly, resulting in relatively small BSAF values (Drouillard et al., 2007; Shang et al., 2013). Compounds with higher Kow had stronger affinity bound to sediments, which led to lower bioavailable pollutants for organisms and resulted in small BASF values (Qiu et al., 2019; Wu et al., 2019). Additionally, more significant molecular steric hindrance would limit pollutants with higher Kow from the environment into cell membranes (Shaw and Connell, 1982).

    • Polychlorinated biphenyls (PCBs) in soils from typical paddy fields of China: Occurrence, influencing factors and human health risks

      2022, Environmental Pollution
      Citation Excerpt :

      As a typical group of persistent organic pollutants (POPs) under the Stockholm Convention, the persistence, high toxicity and bioaccumulation ability of PCBs have been well known (ATSDR, 2000; Huang et al., 2022). Despite the fact that the production and application of PCBs have been severely restricted for nearly 50 years, the ubiquitous existence of PCBs has been found in agricultural soils by many studies (Mao et al., 2021; Sun et al., 2016; Wu et al., 2019). Local inputs, such as disposal of PCB-containing products (Sun et al., 2016), release from unintentional sources like iron–steel manufacturing, copper smelting processes, combustion processes, and production of pigments, paints and polymer sealants (Hsu et al., 2003; Kuzu et al., 2013; Mao et al., 2021), irrigation with polluted water (Teng et al., 2013) and application of agrochemicals with PCBs as additives (Wang et al., 2010), have been identified as the potential sources of PCBs in agricultural soils.

    View all citing articles on Scopus
    View full text