Reducing overall herbicide use may reduce risks to humans but increase toxic loads to honeybees, earthworms and birds

Environmental Sciences Europe

Table 7 Toxic loads (TL) rankings of herbicide AIs used in 2019 in Austria for honeybees (A. mellifera), earthworms (E. fetida) and birds (S. serinus), share on total TL for each organism, change 2010 vs 2019 and parameters from linear models testing changes of toxic loads, P-values in bold if significant, arrows indicate the direction of the change

Rank	Active ingredient	LD₅₀	Half-life [days]	Share on TL 2019 (%)	Change 2010–19 (%)	R²	F-value	P-value
Honeybees		[µg bee⁻¹]
1	Diquat	13.0	5500	92.6	646	0.65	15.08	0.005	↑
2	Iron sulphate	100.0	1000	4.7	187	0.67	16.54	0.004	↑
3	Terbuthylazin	22.6	22	0.6	− 6	0.17	1.61	0.240
4	Glyphosate	100.0	24	0.4	− 38	0.36	4.43	0.069
5	Pendimethalin	101.2	101	0.4	− 27	0.15	1.25	0.300
6	Chlorotoluron	88.7	70	0.2	4946	0.99	200.70	0.001	↑
7	S-metolachlor	85.0	23	0.2	4	0.02	0.13	0.728
8	Aclonifen	107.0	80	0.2	^a− 2	0.00	0.01	0.925
9	Flufenacet	100.0	39	0.1	19	0.02	1.21	0.304
10	Nicosulfuron	5.2	19	0.1	198	0.46	6.74	0.032	↑
Earthworms		[mg earthworms⁻¹]
1	Diquat	193.0	5500	94.9	646	0.65	15.08	0.005	↑
2	Iron sulphate	7838.0	1000	0.9	187	0.67	16.54	0.004	↑
3	Aclonifen	307.1	80	0.9	^a− 2	0.00	0.01	0.925
4	Terbuthylazin	290.1	22	0.7	− 6	0.17	1.61	0.240
5	Flufenacet	448.3	39	0.4	19	0.13	1.21	0.304
6	Prosulfocarb	147.0	10	0.3	122	0.72	20.68	0.002	↑
7	Pendimethalin	2047.0	101	0.3	− 27	0.15	1.25	0.300
8	MCPA	665.3	25	0.3	42	0.49	7.70	0.024	↑
9	S-metolachlor	1166.8	23	0.2	4	0.02	0.13	0.728
10	Dimethenamid-P	602.6	16	0.2	77	0.18	1.77	0.221
Birds		[mg bird⁻¹]
1	Diquat	0.4	5500	97.3	646	0.65	15.08	0.005	↑
2	Iron sulphate	8.4	1000	1.7	187	0.67	16.54	0.004	↑
3	Chlorotoluron	2.2	70	0.2	4946	0.99	200.70	0.001	↑
4	MCPA	1.6	25	0.2	42	0.49	7.70	0.024	↑
5	Pendimethalin	6.4	101	0.2	− 27	0.15	1.25	0.300
6	Glyphosate	15.4	24	0.1	− 38	0.36	4.43	0.069
7	Terbuthylazin	8.5	22	0.1	− 6	0.17	1.61	0.240
8	Metribuzin	1.1	19	< 0.1	76	0.68	16.97	0.003	↑
9	Aclonifen	13.7	80	< 0.1	^a− 2	0.00	0.01	0.925
10	S-metolachlor	11.3	23	< 0.1	4	0.02	0.13	0.728

LD₅₀ and half-life date from [91]
^a%-change from 2015 to 2019 only, because data for aclonifen were missing in 2010