Shatapatha Brahmana 3.8.5.9

3.8.5.9

atha hṛdayaśūlam prayacati | tanna pṛthivyām parāsyennāpsu sa yatpṛthivyām parāsyedoṣadhīśca vanaspatīṃścaiṣā śukpraviśedyadapsu parāsyedapa eṣā śukpraviśettasmānna pṛthivyāṃ nāpsu

He (the slaughterer) then hands the heart-spit (to the Adhvaryu). Let him not throw it on the ground, nor into the water; for were he to throw it on the ground, that anguish would enter into the plants and trees; and were he to throw it into the water, that anguish would enter into the water: hence neither on the ground, nor into the water.