Toxicity of atrazine and metribuzin herbicides on earthworms (Aporrectodea caliginosa) by filter paper contact and soil mixing techniques

Herbicides used on a regular basis could endanger non-target species like earthworms. The aim of this work was to test the toxic effect of atrazine and metribuzin on Aporrectodea caliginosa by filter paper contact and soil mixing techniques. Atrazine had the highest intrinsic toxicity to earthworms, with LC50 of 0.026 µg mL-1 after 72 hr of treatment. While the LC50 of metribuzin was 0.063 µg mL-1 after 72 hr by filter paper contact test. LC50 was reduced from 11.121 to 3.118 and 164.824 to 19.113 μg g soil-1 in clay soil, from 32.221 to 17.33 and 324.141 to 41.028 μg g soil-1 in soil (1:1) and from 41.234 to 30.804 and 462.255 to 70.902 μg g soil-1 in sandy clay loam soil of atrazine and metribuzin after 5 and 10 day. Generally, atrazine is more toxic than metribuzin in both tests.