Informal E-waste dismantling activities accelerated the releasing of liquid crystal monomers (LCMs) in Pakistan: Occurrence, distribution, and exposure assessment

Yanhui Ge; Jingren Cui; Lianying Zhang; Shaohan Zhang; Mujtaba Baqar; Zhipeng Cheng

doi:10.1016/j.scitotenv.2024.172987

Informal E-waste dismantling activities accelerated the releasing of liquid crystal monomers (LCMs) in Pakistan: Occurrence, distribution, and exposure assessment

Sci Total Environ. 2024 Jul 1:932:172987. doi: 10.1016/j.scitotenv.2024.172987. Epub 2024 May 10.

Authors

Yanhui Ge¹, Jingren Cui², Lianying Zhang¹, Shaohan Zhang³, Mujtaba Baqar⁴, Zhipeng Cheng⁵

Affiliations

¹ School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin 300384, China.
² School of Environmental Science and Safety Engineering, Tianjin University of Technology, Tianjin 300384, China; MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
³ MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China.
⁴ MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China; Sustainable Development Study Centre, Government College University, Lahore 54000, Pakistan.
⁵ MOE Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University, Tianjin 300350, China. Electronic address: chengzhipeng@nankai.edu.cn.

PMID: 38734084
DOI: 10.1016/j.scitotenv.2024.172987

Abstract

Liquid crystal monomers (LCMs) are emerging contaminants characterized by their persistence, bioaccumulation potential, and toxicity. They have been observed in several environmental matrices associated with electronic waste (e-waste) dismantling activities, particularly in China. However, there is currently no information on the pollution caused by LCMs in other developing countries, such as Pakistan. In this study, we collected soil samples (n = 59) from e-waste dismantling areas with different functions in Pakistan for quantification analysis of 52 target LCMs. Thirty out of 52 LCMs were detected in the soil samples, with the concentrations ranging from 2.14 to 191 ng/g (median: 16.3 ng/g), suggesting widespread contamination by these emerging contaminants. Fluorinated LCMs (median: 10.4 ng/g, range: 1.27-116 ng/g) were frequently detected and their levels were significantly (P < 0.05) higher than those of non-fluorinated LCMs (median: 6.11 ng/g, range: not detected (ND)-76.7 ng/g). The concentrations and profiles of the observed LCMs in the soil samples from the four functional areas varied. The informal dismantling of e-waste poses a potential exposure risk to adults and infants, with median estimated daily intake (EDI, ng/kg bw/day) values of 0.0420 and 0.1013, respectively. Calculation of the hazard quotient (HQ) suggested that some LCMs (e.g., ETFMBC (1.374) and EDFPB (1.257)) may pose potential health risks to occupational workers and their families. Considering the widespread contamination and risks associated with LCMs, we strongly recommend enhancing e-waste management and regulation in Pakistan.

Keywords: E-waste; Informal activities; Liquid crystal monomers; Risk assessment; Soil.

MeSH terms

Electronic Waste* / analysis
Environmental Exposure / statistics & numerical data
Environmental Monitoring* / methods
Humans
Liquid Crystals*
Pakistan
Risk Assessment
Soil Pollutants* / analysis