Table 1.

Abundance of extracellular (eDNA) and intracellular DNA (iDNA) in different environments

Environment	Environment	eDNA	iDNA	References
Water (ng ml−1)	Influent water	9.0–12.5	NA	[30]
	Effluent water	4.3–8.6	NA	[30]
	Waste water treatment plant	2.5 ± 0.4–15.9 ± 0.4	1.4 ± 0.2–10255.0 ± 162.6	[31]
	Waste water treatment plant	1.1 ± 0.0–7.8 ± 2.8	0.1 ± 0.0–20843.3 ± 4077.6	[31]
	Seawater	5.1 ± 0.6 × 103	NA	[32]
	Seawater	1–88	NA	[33]
	Forest lake water	9–11	NA	[34]
	Drinking water	0.033–0.39	NA	[35]
Sediment (μg g−1)	Activated sludge	5.6–12.3 ng ml−1	NA	[30]
	Sludge	10.5–119.1	335.4–2047.4	[36]
	Sediment	0.94–6.23	2.78–17.13	[37]
	Livestock waste management structures sediment	0.6–9.2	190.0–1005.3	[38]
	Activated sludge	4.2–52.2 × 103	NA	[39]
	Swine manure	8.6–9.7	179.0–295.4	[36]
	Sediment	0.023 ± 0.001	0.0005 ± 0.0001	[40]
	Aquatic sediment	6.7–24.3	0.31–0.67	[41]
	Aquatic sediment	77–116.8	63.7–89.7	[8]
	Sediment	2.3–57.7	NA	[29]
	Surface sediments	9.4 ± 3.0–22.5 ± 4.8	NA	[42]
	Sediment	0.0047 ± 0.0003–5.58 ± 1.26	NA	[24]
	Marine sediment	0.03–4.45 μg cm−3	0.03–5.84 μg cm−3	[43]
	Sea sediments	1.460–1.69	NA	[32]
	Marine sediment	3.3 ± 0.9–21.2 ± 1.3	NA	[24]
	Sea sediment	0.63 ± 1.59	0.035 ± 0.004	[40]
	Sea sediment	0.056 ± 0.001	0.010 ± 0.001	[40]
	Deep‐sea sediment	0.31 ± 0.18 g cm−2	NA	[16]
	Urban lake sediment	5.6–11.4	24.9–46.2	[36]
	Forest lake sediment	0.069–0.52	NA	[44]
	Ferruginous sediment	0.3–0.6	0.3–0.9	[45]
Soil (μg g−1)	Forest soil	2.2–41.1	NA	[46]
	Forest soil	7–55	29–197	[47]
	Forest soil	6.07	11.46	[48]
	Forest soil	1.70–1.90	NA	[49]
	Forest soil	6.0	NA	[50]
	Soil	0.08–1.95	NA	[44]

Abbreviation: NA, not available.