Table 1. Sediment Microplastic Concentration ([MP]) and Richness (S), Diversity (H and D) and Evenness (E_H) Indexes at Each Sampling Site.

sites		[MP] (microplastic g–1)						S	H	D	EH
		0–1 cm	1–2 cm	2–3 cm	3–4 cm	7–8 cm	average per site
urbana	2	0.78	0.14	0.13	0.03	0.23	0.26	9	1.84	5.0	0.84
	4	2.54	0.36	0.85	0.10	0.04	0.78	6	1.46	3.5	0.82
	5	0.91	0.45	0.63		0.03	0.41	10	1.83	3.9	0.80
	7	1.18	1.44	0.20	0.38	0.18	0.68	11	2.05	6.0	0.85
	8	0.58	0.06	0.67	0.08		0.28	7	1.91	6.5	0.98
	9	0.93	0.07	0.29	0.09	0.03	0.28	8	1.80	4.6	0.86
	13	1.15	1.25	2.03	2.17	0.71	1.46	11	1.94	5.6	0.81
	14	0.75	0.93	0.92			0.52	6	1.39	3.0	0.78
	15	0.86	0.08	0.96	0.10		0.40	7	1.85	5.8	0.95
	16	0.20	0.37	0.18	0.41	0.06	0.25	8	1.87	5.7	0.90
natural	1	0.14		0.08	0.12		0.07	3	0.95	2.3	0.86
	3			0.04		0.15	0.04	4	1.33	3.6	0.96
	6	0.05		0.10		0.06	0.04	3	0.95	2.3	0.86
	10	0.24		0.20		0.07	0.10	3	1.05	2.8	0.96
	11b	0.13	0.24		0.24		0.12	4	1.24	3.0	0.90
	12	0.19					0.04	1	0.00	1.0
	17	0.04					0.01	1	0.00	1.0
	18	0.13					0.03	1	0.00	1.0
	19		0.33	0.14	0.46		0.18	5	1.55	4.5	0.96
	20		0.05		0.15		0.04	3	1.04	2.7	0.95
average per depth	0.54	0.29	0.37	0.22	0.08

^aSites showing average sediment microplastic concentrations greater than 0.20 microplastic g^–1. All these sites, except one (site 16) which is located in an agriculture influenced area, are located in high urban influenced areas (Figure 1c).

^bSite 11 is located near an urban zone (Figure 1c) but does not display patterns regarding microplastic sediment concentration, diversity, evenness, and richness that are similar to the other urban-influenced sites. It was therefore considered as a natural site.