“In hardwater, the stimulatory effect of AHA on Jmax persisted even in the presence of 300 microg l(-1) Cu2+, whereas both AHA and NOM prevented the increase in Km caused by Cu2+ ; these effects were reflected in Jin measurements.”
“In softwater, AHA helped to protect against the increased Km caused by high Cu2+ , but there was no protection against the inhibition of Jmax.”