*Microplastic Contaminants in the Sediment of the East Coast of Saudi Arabia DOI: http://dx.doi.org/10.5772/intechopen.109019*

with an average size of 1.55 ± 0.94 SD mm and an overall average abundance of 11.5 ± 5.02 SD particle/kg (109.4 ± 50.26 SD particle/m2 ). The highest abundance among the low tide is found in the Dammam sample with an average of 21.2 ± 0.68 SD particle/ kg (152.8 ± 21.3 SD particle/m2 ), while the lowest is in the Jubail sample with an average of 5.5 ± 1.56 SD particle/kg (51.1 ± 14.71 SD particle/m2 ). On the other hand, Salwa has the highest abundance among the high tide with 16.5 ± 4.98 SD particle/kg (204.5 ± 64.15 SD particle/m2 ) and Jubil is the least with 6.3 ± 4.06 SD particle/kg (50.6 ± 31.21 SD particle/m2 ) (**Figures 2** and **3**). No significant differences were reported between the overall low tide average abundance (12 ± 5.94 particle/kg, 112.5 ± 40.08 SD particle/m2 ) and overall high tide average abundance (11 ± 3.85 particle/kg, 106.3 ± 58.54 SD particle/m2 ). However, when low tide and high tide average microplastic abundance were compared for each site separately, discrepancies were observed in all of the beaches except the Jubail sample. The low tide abundance average was higher than the high tide in Dammam and Khafji, but the opposite was reported in Salwa.

Average particle size was showing no significant variation between both low tide (1.53 mm) and high tide (1.58 mm). Microplastics with a size range from 1 to 2 mm were the most common size with 44%, followed by particles that were less than 1 mm in size (33%), then the range from 2 to 3 mm (14%). Therefore, only 9% of the collected particles were bigger than 3 mm (**Figure 4**).

**Figure 2.**

*Average microplastic abundance (particle/kg).*

#### **Figure 3.** *Average microplastic abundance (particle/m2 ).*

**Figure 4.** *Microplastic size distribution.*

Regarding microplastic types, 96% of the collected particles were fibers leaving only 4% as fragments and filaments. Fragments and filaments were found in both low-tide and high-tide samples.

Different colors of microplastic particles were observed in all the samples. The majority is for transparent (34%) followed by blue (30%), black (17%), red (15%), and green (4%).

Using ATR-FTIR analysis, four different polymers as polyethylene terephthalate (PET), polyethene (PE), high-density polyethylene (HDPE), and polypropylene (PP) were identified. Fibers with different colors (transparent, blue, and red) were found to be PET. PE and HDPE were found in fragments and filaments with blue, green, and transparent colors while only one white fragment was found in PP (**Figure 5**).

Statistical analysis using the Kolmogorov–Smirnov test shows that microplastic abundance and size are normally distributed. One-way analysis of variance (ANOVA) shows no significant differences between microplastic abundance, size, and color considering p < 0.05 as statistically significant.
