Overview of microplastics pollution with heavy metals: Analytical methods, occurrence, transfer risks and call for standardization

• Published in: Journal of hazardous materials Vol. 415; p. 125755
• Main Authors: Kutralam-Muniasamy, Gurusamy, Pérez-Guevara, Fermín, Martínez, I. Elizalde, Shruti, V.C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.08.2021
• Subjects: Adsorption; Environmental pollutant; Marine; Sediment; Standardization; Trace elements; Trace elements; Sediment; Marine; Environmental pollutant; Adsorption; Standardization
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.125755

The identification and quantification of metals in microplastics are necessary to determine their exposure levels as well as to understand their potential toxicity in the environment linked to the ubiquity of microplastics. The readiness of effective protocols and measurement techniques for accurate metal quantification is of utmost importance. This first review, based on 28 original articles, provides a systematic assessment of the current protocols for extraction, detection and quantification of metals in microplastics and the challenges associated with them. Quality assurance and quality control measures are also summarized. Great variations of microplastic samples in terms of characteristics, number, mass and unit were noted. Wet acid and microwave acid digestion methods were commonly employed for metal extraction from microplastics using a combination of acids such as HF, HCl, HNO3 and H2SO4 at different concentrations and reaction conditions. Adaptation of one or multiple characterization techniques including, inductively coupled plasma-optical emission spectroscopy, inductively coupled plasma mass-spectrometry, X-ray fluorescence and atomic absorption spectroscopy has been considered. The discrepancies in methodology and elements analyzed between studies produce variable results and troublesome comparison. Having considered the need for a standard procedure, this review highlighted several suggestions towards standardization and recommended perspectives for future research. [Display omitted] •Microplastics are vectors of heavy metals in the environment.•First review on heavy metals presented in microplastics pollutants.•Significant methodological discrepancy between studies reviewed is noted.•Occurrence of heavy metals in microplastics is summarized and discussed.•Current analytical challenges and future research directions are presented.