Table 2.

Estimates of number of laundry loads washed to produce microfiber counts observed in the present study, depending on laundered material type.

Estimate by synthetic material type	Polyester:cotton blend	Polyester	Acrylic
# Microfibers per 6 kg load a	138,000	496,000	728,000
WWTP	# of 6 kg loads per capita per week, based on average MP/capita/week
Rifle Range Rd (RR)	1.5	0.4	0.3
Center Street (CS)	1.6	0.5	0.3
Plum Island (PI)	2.5	0.7	0.5
Range datab	# of 6 kg loads per capita per week, for lowest and highest count data
Low: RR 041417	1.4	0.4	0.3
High: PI 071517	5.6	1.6	1.1

^aNapper and Thompson (2016).

^bLowest and highest count data from the data set: date is given as MMDDYY.