(1) “In our samples, ninety percent of the plastics we are finding are microfibers… Those are often times originating from textiles or other fibrous synthetic products.”
What does "times" in the sentence mean?
"Oftentimes" (one word now, not two) is an adverb meaning "frequently" here. The OED's definition, with quotations, is below:
Now chiefly North American; otherwise archaic or literary.
1. Many times; on many occasions; in many cases; frequently, often.
▸ a1393 Gower (Fairf.) v. 4777 (MED) Often times of scarsnesse It hath be sen that for the lesse Is lost the more.
1417 in R. W. Chambers & M. Daunt (1931) 290 (MED) Right trusty and Welbeloued brother, We grete yow often tymes Wel.
1444 V. 117/2 He to forfaite as often tymes as he offendith.
c1475 (▸1392) Surg. Treat. in f. 118v (MED) Þou schalt often tymes anoynte þe place wiþ colde symple medicyns.
a1500 (▸?c1400) (Cambr.) (1937) 60 The kynge..oftentymes dyde wepe.
1541 T. Elyot vii. f. 15v He shalbe so oftentymes warned.
1567 G. Fenton tr. M. Bandello 494 Whereupon followeth oftentimes a number of indifferent mishaps.
1611 Heb. x. 11 Offring oftentimes the same sacrifices.
1668 in (1935) I. 147 He was ofintymes callit and did not compeir.
1720 J. Quincy tr. N. Hodges v. 138 Those which went no further than the Skin, would oftentimes slough off.
1774 J. Bryant I. 495 These buildings were oftentimes light-houses.
1800 Wordsworth Pet-lamb in (ed. 2) II. 143 This song to myself did I oftentimes repeat.
1846 R. C. Trench ii. 33 An oftentimes fatal readiness.
1876 18 180 They ‘gag’ to such an extent that the author oftentimes does not recognise his own dialogue.
1902 15 14 It is oftentimes difficult to discover their identities, since they bear many attributal or descriptive names.
1960 M. S. Bishop ix. 135 Oftentimes the gentle slopes of paleotopographic surfaces are indicative of much steeper dips on the underlying beds.
1994 22 July 9/3 Often times we tend to forget that all economies (whether developed, developing or undeveloped) are interdependent.
(2)“So you think about the, you know, literally millions of garments like this that are being washed every day. And..."
What is "the" after "about"?
"The" introduces the noun phrase "the millions of garments," into which both a parenthetical insertion ("you know") and an adverb ("literally") have been added. The noun phrase is also post-modified by a prepositional phrase ("like this") and a relative clause ("that are being washed every day").
The entire noun phrase is "the, you know, literally millions of garments like this that are being washed every day." That noun phrase functions as the object of the preposition "about" in "think about." "You know" is just conversational filler, like "uh," but some linguists might classify it as a pragmatic "discourse marker."