The global variability of diatomaceous earth toxicity: a physicochemical and in vitro investigation

Table 1 Information for diatomaceous earth samples, including: particle size distribution, surface area and chemical composition

Sample information				Particle size distribution (c.v. %)		BET surface area (m²/g)		Chemical composition (wt.%)
Sample ID	Source	Process	Grade	<4 μm	<10 μm	Mean	s.d.	SiO₂	TiO₂	Al₂O₃	Fe₂O₃	MgO	CaO	Na₂O	K₂O
DE_05^#a	Spain	U	Filler	11.3	38.8	7.5	0.7	90.47	0.05	0.91	0.38	0.34	6.96	0.65	0.14
DE_11^b	Spain	U	Filler	12.4	47.3	6.3	0.4	87.26	0.05	1.40	0.42	0.49	8.96	1.04	0.17
DE_13^c	France	U	Filter aid	7.8	28.0	22.9	0.2	89.02	0.64	4.42	3.22	0.36	0.66	0.38	0.35
DE_15^d	France	U	Filter aid	7.9	28.5	23.8	0.3	87.40	0.70	4.73	3.99	0.49	0.74	0.19	0.34
DE_16^d	France	C	Filter aid	6.7	25.0	3.8	0.1	88.03	0.66	4.50	3.86	0.39	0.66	0.17	0.33
DE_18	China	C	Filter aid	7.3	28.1	3.1	0.1	93.49	0.15	3.71	1.67	0.35	0.08	−0.04	0.50
DE_20^#	Mexico	C	Filter aid	6.8	25.3	4.0	0.1	92.00	0.24	5.07	1.95	0.34	0.30	−0.13	0.20
DE_21	USA-1^e	C	Filter aid	6.2	21.7	5.7	0.2	87.83	0.32	6.57	1.81	1.02	0.54	0.51	1.02
DE_22	USA-1	C	Filler	25.4	71.5	10.6	0.2	93.24	0.17	3.82	1.15	0.65	0.17	0.03	0.59
DE_23	USA-1	C	Filter aid	21.8	65.5	6.8	0.2	93.88	0.15	3.03	1.05	0.69	0.30	0.21	0.47
DE_24^#	Mexico	C	Filter aid	12.1	45.0	5.9	0.2	93.63	0.19	3.89	1.49	0.33	0.22	0.01	0.18
DE_06^a	Spain	FC	Filler	8.5	34.4	1.1	0.1	91.27	0.03	0.67	0.35	0.27	6.25	1.00	0.09
DE_07	USA-1	FC	Filler	10.6	31.6	1.3	0.0	91.67	0.15	3.00	1.07	0.53	0.29	2.69	0.48
DE_08^#	USA-2^e	FC	Filler	9.2	28.7	1.3	0.1	93.07	0.06	1.12	1.99	0.51	0.30	2.89	0.03
DE_09	Chile	FC	Filler	9.8	33.4	1.5	0.1	93.04	0.10	1.82	0.95	0.23	1.29	2.15	0.34
DE_10^#	Mexico	FC	Filler	8.7	35.3	1.7	0.1	93.64	0.10	2.05	0.80	0.14	0.32	2.59	0.12
DE_12^b	Spain	FC	Filler	8.5	33.4	1.0	0.1	90.67	0.03	1.12	0.35	0.31	6.64	0.69	0.10
DE_14^c	France	FC	Filter aid	6.4	17.0	1.1	0.1	87.36	0.58	4.10	2.61	0.40	0.62	3.17	0.39
DE_17	China	FC	Filter aid	4.6	11.4	1.0	0.0	91.68	0.13	3.12	1.44	0.27	0.11	2.22	0.51

Table sorted by process: U unprocessed, C calcined, FC flux-calcined, c.v. cumulative volume, s.d. standard deviation (n = 3). ^#The fine fractions of these samples were separated for use in toxicology assays. ^e Samples were sourced from two separate deposits in the USA and so are denoted as USA-1 and USA-2.^a–d Unprocessed samples and their corresponding processed samples

ISSN: 1745-6673