Dataset: Low-density microplastics (LD-MPs) in seven recreational parks of Al Ain, UAE isolated by density flotation method (DFM)

Published: 2 January 2024| Version 1 | DOI: 10.17632/nthrjr322s.1
Rener De Jesus,


The LD-MPs from 104 soil samples collected from seven different recreational parks of Al Ain, UAE were isolated by DFM using saturated sodium chloride solution (1.2 g/cm3). A total of 10, 701 g of soil samples were processed for this study (Loc_Info_Micp_count.xlsx). Prior to extraction and isolation of MPs, the 10 ± 0.1 g of each sample were dried at 40 degrees Celsius for 24 hr and then filtered using a stack of 8" dm stainless steel sieves with aperture of 5 mm and 1mm. An aliquot of 5 ± 0.1 g were subjected for DFM. After that, the sample was filtered using a Whatman glass microfiber filter to separate LD-MPs from the liquid. The filter was then viewed under stereomicroscope. The physical characteristics of LD-MPs, such as size, color, and shape, were noted (Loc_info_Micp_count.xlsx). Microplastic concentration were determined and expressed as particles per kg of samples (Micp_conc_per_sampling_site.xlsx; Table 8). Statistical data of isolated LD-MPs sizes were computed (Stat_data_of_LD-MPs_size.xlsx; Table 9). The study also tried to correlate the LD-MPs concentrations with soil pH and moisture content. Results showed that there is a negative correlation in MPs concentrations and the two selected soil properties suggesting potential negative effects in soil health (Stat_data_soil_pH_moisture_content.xlsx; Tables 10 & 11). FTIR analyses were conducted to initially determine the possible polymers present in the isolated LD-MPs (SFig3_FTIR). Polymers identified were possibly polyethylene, polypropylene, polyethylene terephthalate, or polyvinyl chloride. These results found that the presence of LD-MPs in urban recreational parks might contribute to impending environmental negative effects.


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Soil samples were taken from seven recreational parks in Al Ain, UAE using a sterile stainless-steel sample probe (HiHydro, T-style, 12 inch). A total of 10,701 g (n=104) of soil samples were gathered. and GPS were recorded (Garmin e Trex®10). Each sample was placed in a brown paper bag (29 × 9.2 × 5 cm) and transported immediately to the laboratory for further analysis. For microplastic extraction, each sample (10.0 ± 0.1 g) was dried at 40°C for 24 h. Then, filtered through a stack of 8" dm stainless-steel sieves (GlenammarTM) with apertures of 5 mm and 1 mm, followed by the density flotation method (DFM) with saturated NaCl solution (1.2 g/cm3). An aliquot of 5.0 ± 0.1 g from each filtered sample was placed in a clean Erlenmeyer flask, added with 50 mL saturated NaCl solution and stirred for 30 min. After rinsing, the flask was left undisturbed for 48 h. The liquid portion contains LD-MPs. The liquid was siphoned, transferred into a clean beaker, and filtered by a vacuum filtration system. The filter paper used was a glass microfiber filter (Whatman® pore size 1.2 µ, 4.7 cm), and the filtration process was performed twice. To verify LD-MPs, residues on the filter were brushed onto a glass Petri dish using a sable series 16 (Winsor & Newton) paintbrush (no.3) with weasel hairs to prevent contamination. The dish was viewed under a stereomicroscope (AmScopeTM) at a magnification of 40×. A hot needle test (De Witte et al., 2014) was performed for isolation of suspected LD-MPs. Controls were low-density polyethylene (LDPE) microbeads and cotton fibers. Each plastic particle was photographed and measured using ImageJ 1.53t Java 1.8.0_345 (64-bit). The isolated LD-MPs were subjected to visual color identification using the 120-palette code (SFig2). Descriptive statistical analysis was performed to summarize the measurements and observe microplastic color. Kruskal-Wallis test was performed to analyze microplastic concentration and size distribution between sampling sites. Representative LD-MPs were subjected to spectroscopic analysis using FTIR spectrometer (Thermo Nicolet Nexus 470 FTIR, USA) and equipped with DTGS detector. To measure soil pH, distilled water extraction was performed using a benchtop pH meter (Denver Instrument, Basic pH meter 13183). To measure moisture content, each sample was weighed (5.0 ± 0.1 g) before air-drying then placed in a hot-air oven at 105°C until a constant mass was achieved. The moisture content was measured using the formula: moisture content [%] = (wt. of sample before oven drying ˗ wt. of sample after oven drying / wt. of sample before oven drying) *100. A simple linear regression was used to evaluate the correlation of soil pH and moisture content to the number of LD-MPs, while the Kruskal-Wallis test was performed to determine if there were significant difference between sampling sites in terms of the LD-MPs concentration. Spike-recovery experiment was conducted to ensure the accuracy of DFM.


United Arab Emirates University


Plastics, Environmental Science, Fourier Transform Infrared Spectroscopy, Soil, Environmental Pollution, Urban Environmental Pollution, Soil pH, Soil Moisture, Soil Pollution, Microplastics