TITLE:
Understanding Fate and Effects of Copper Pesticides in Aquatic Systems
AUTHORS:
Ben E. Willis, West M. Bishop
KEYWORDS:
Sediments, Risks, Bioavailability, Algaecide, Herbicide, Copper
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.4 No.5,
May
6,
2016
ABSTRACT: Copper
sulfate and other chelated or complex copper forms are commonly used to manage
nuisance and noxious algae and invasive weeds through direct application to
aquatic systems. Regulatory scrutiny and perceived non-target species impacts
supported the need for an accurate risk assessment of fate and effects of
copper applied as a pesticide. Copper inputs to aquatic systems originate from
numerous sources (e.g. natural, storm water, industrial) whereas direct
pesticide applications account for approximately 13%. Following a pesticide
application, copper rapidly partitions to suspended algae and particulates and
the majority (>90%) of applied copper is transferred to sediments within 2
days. Copper subsequently shifts to less bioavailable forms and risks to
non-target species are significantly decreased. Additionally, the copper that
partitions to sediments is diluted through migration to greater sediments
depths and accretion. Even when elevated sediment copper concentrations were
measured following chronic applications or high treatment levels, no adverse
effects to non-target species were observed with laboratory or field
experiments. When used appropriately copper can be an effective tool for water
resource managers with negligible environmental impact.