Arsênio, mercúrio e chumbo em Steiner (2007)

What is the truth in this connection? Great Nature does not leave us so mercilessly in the lurch if we fail to take the silicic acid or the lead or mercury or arsenic into account, as she does if we fail to take into account her potash or limestone or phosphoric acid. Heaven provides silicic acid, lead, mercury, and arsenic — provides them freely with the rain. On the other hand, to have the proper phosphoric acid, potash and limestone-content in the Earth, we must till the soil and manure it properly. Heaven does not give these things of her own accord. (Steiner 2007:44)

STEINER, Rudolf. 2007. The Agriculture Course. (Trans.: George Adams) Shrewsbury: Wilding & Son Ltd.