Certain manufacturers of Pond equipment decided to borrow a
technology from the Swimming Pool industry and, with maybe some minor tweaks,
promote it as an exciting breakthrough in controlling Pond algae. Presenting
the IONIZER!
Through the controlled release of Copper, Zinc and Silver
ions into the pond’s water column, algae growth can be controlled and in many
cases eliminated. This, on the surface, is great news for Pondkeepers. No
longer is it necessary to use expensive and hard-to-correctly-measure chemicals.
Just set the Ionizer to the desired level and algae disappears.
Sounds great! However, there is more to be considered than just
what the advertisements claim. What are the other potential and likely results
from use of this device that the manufacturers are not telling us?
Let’s look at some of the manufacturers’ claims as regards
Ionizers.
Company
#1 - “Destroys Bacteria
Kills Algae
Reduces chemical cost
Eliminates chemical
odors
Reduces maintenance
Environmentally
Friendly
Costs pennies per
month
Helps reduce filtration
Fish safe
Includes 2" T
Fitting”
Company #2 - “Safe for fish and plants
Low maintenance
Clears water without
the use of harsh chemicals
Easily installed in
any new or existing water feature
Treats ponds up to
25,000 gallons
Level of
mineralization is controlled by the LED panel
Cast mineral anodes are
self-cleaning
1 year warranty”
Company
#3 –“Drastically reduces pond maintenance
Crystal clear water without the
use of chemicals
Eliminates unsightly water conditions
Simple to install
Safe for fish and plants
Not toxic to animals that may
drink from the pond
Energy efficient (less than $ 1 a
month in electricity cost)
Treats ponds up to 25,000
gallons”
Understandably,
the first concern of a Pondkeeper is whether a product or treatment is safe for
fish. All three (3) of these manufacturers declare that the (proper) use of
this device is safe for fish. Let’s take a closer look at this claim.
All
Three (3) manufacturers include test strips for monitoring Copper levels with
Two (2) of the manufacturers recommending maximum Copper levels at 0.25 mg/L
and the remaining manufacturer recommending 0.30 mg/L as the maximum level of
Copper.
Copper
is a heavy metal and in low concentrations can be toxic. In addition, like
other heavy metals, such as Mercury, it is a bio-accumulate. This means that
once it is ingested by an organism it remains in that organism for an extended
period of time, in many cases, for life. Any additional ingestion only
increases the level that is already present in the organism until eventually a
certain level of toxicity is reached. For terrestrial organisms, this level is
determined primarily by the ingestion of food and water, but for aquatic
organisms, if the Copper is in suspension as ions, it may be ingested during
the respiration process also, as is the case with fis juvenile amphibians,
certain insect larvae, true aquatic invertebrates and bacteria as well as the
target taxa of algae. In the case of fish, it causes increased mucous
production on the skin and the gills where it eventually interferes with the
respiration process by blocking the absorption of Oxygen.
In
assessing the potential toxicity of any substance to any organism, two (2)
distinct levels must be determined, acute (immediate short term) and chronic
(long term). Heavy metals have long been known to play an important beneficial
and cricial role in animal and plant physiology, but at levels so low that they
are undetectable by standard testing.
Considerably
greater attention has been given, in recent years, to the effect of Heavy
Metals and other chemical compounds on the environment. Research is ongoing in
both the public and private sector. This research has resulted in some
universally accepted toxicity levels as regards Heavy Metals.
The
focus here will be on Copper. Copper, after Mercury, is the most toxic of the
Heavy Metals. Copper’s toxicity is greatly influenced by water Hardness and pH.
As water Hardness and ph increase, the toxicity of Copper is reduced. Here is
an example of a couple of simple formulae that are used to define the accepted
level of Copper in fresh water.
Maximum Copper levels (in micrograms) at
any time—0.094(hardness)+2 (where water Hardness is reported as mg/L CaCO3.
30 day average Copper levels (in
micrograms)—0.04 average hardness (where water Hardness is reported as
mg/L CaCO3.
(Environmental Protection Division,
Ministry of Environment, Government of British Columbia)
Note
- There are other formulas used by different government entities worldwide, but
the final accepted levels of Copper vary by only a few micrograms.
Using
these two (2) formulae, in water with a Hardness of 120 ppm for example, we
find the recommended Copper levels to be 13 micrograms/L at any one time and the
30 day average should not exceed 5 micrograms/L Knowing that one milligram equals 1000
micrograms, these results expressed in mg/L would be 0.013 mg/L and 0.05 mg/L.
These results appear to be on the conservative side, but considering the fact
that some aquatic organisms have a very low tolerance to Copper, these formulae
are quite appropriate.
These
are the Metal Safe Limit levels as defined in the Textbook of Fish Health:
Copper 0.014mg/l More toxic in soft water; Zinc exacerbates toxicity; Combined
both are dangerous; Zinc 0.01mg/l Synergistic with copper; 0.15mg/l In hard
Water; Cadmium 0.03mg/l; Chromium 0.10mg/l; Lead 0.01mg/l In soft Water;
4.00mg/l In hard Water; Silver 0.03mg/l (mg/l is the same as ppm).
The
author was unable to find any scientifically set copper toxicity levels for
Koi, but several anecdotal sources were found that stated that Koi begin to
show copper toxicity at 0.03 ppm along with the copper toxicity level for Koi
at 0.3 ppm., which is at or extremely close to the Maximum levels suggested by
the manufacturers of these devices. It should be stressed that no scientific
studies were found that substantiated these levels. In fact, one study reported
that Koi fry were unaffected by Copper levels of 1.00 mg/L.
It
is important, however, to know the signs and symptoms of Copper toxicity in
Koi. One of the earliest effects of too
much copper is apparent fish hypoxia, the loss of ability to use oxygen. Common
symptoms of initial acute toxicity are fish gasping, disoriented (ataxic) at
the surface, due to copper's hemolytic (blood cell splitting) and
mucus-producing effects. Copper is a proteinaceous precipitant; that is, it
causes your fish to produce more mucus. This may aid the in the suffocation or
sloughing off of parasites, but also interferes with respiration through their
skin and gills.
Of
greater concern is the previously mentioned fact that all heavy metals are bio-accumulates.
This accumulation leads to immunosuppression.
Fish are often observed suffering from bacterial infections for no apparent
reason. Water quality is optimum but
low levels of copper and/or zinc are present. Metals are most toxic in low
alkalinity and pH. This allows for a higher concentration of metal to remain
dissolved. The accumulation over time immunosuppresses the fish and allows the
normal pathogenic bacteria to gain the upper hand leading to ulceration and
possible septicemia (bacteria in the bloodstream).
In
eco-system ponds, along with the fish, the toxicity of copper to all other
aquatic organisms is of equal importance. Considerably more data is available
on the effects of copper on fresh water fauna due to the fact that they are
present in every natural waterway and their numbers and diversity are prime
indicators of the health of any aquatic eco-system.
Copper
is extremely toxic to most invertebrates and the juvenile forms of most
amphibians.
“Northern
leopard frogs (Rana pipiens) were exposed to environmentally relevant
concentrations of copper in water (control and 5, 25, and 100 microg/L, as
CuSO4) in a static renewal system for 154 d from posthatch stage to
metamorphosis. Tadpole survival, swimming performance, percent metamorphosis,
time to metamorphosis, and survival during and time required for tail
resorption were negatively affected in the 100-microg/L treatment.”
-Adverse effects of chronic copper
exposure in larval northern leopard frogs (Rana pipiens).
Chen
TH, Gross JA, Karasov WH.
Available
toxicity data on amphibians indicate copper 96 h LC50 values calculated in
tadpoles ranged from 0.04 to 5.38 mg/L. Studies of other aquatic organisms show
96 h LC50 values ranging from 0.06 to 6.68 mg/L.
Representative
toxicity levels for some other fresh water organisms are-
Most snails – 8 - 41 micrograms/L;
Cladocerans (including Daphnia) 5 - 213 micrograms/L; Amphipods 8 - 87
micrograms/L
Although
the Mayfly is fairly sensitive to Copper, the majority of insects that have
aquatic larval stages are tolerant, most notable Damselflies and Dragonflies,
which are always expected visitors to any aquatic venue. These Odonates have
the ability to store heavy metals in their exoskeletons where it remains
harmless.
The
inhibition, reduction or elimination of any member group of the aquatic food
chain will have negative effects on the overall health of the eco-system to a
lesser or greater degree depending on which species are residents of that
particular eco-system and their relative position in the food web.. Nevertheless,
any negative effect on an aquatic eco-system’s food chain and/or diversity will
have deleterious effects on the entire system.
The
only organisms that have not been discussed are the bacteria, in particular,
the nitrifying bacteria. The results of studies on the toxic effects of Copper
are quite surprising. Copper and Zinc appear to be the least toxic of the
metals tested. Copper, at low levels, actually stimulates activity in
Nitrobacter. At levels up to 0 50 mg/L the Copper ion has no
toxic effect
on Nitrobacter. Instead, the stimulatory effect is readily apparent......Apparently. at 0 50 mg/L Copper has not reached the cross-over
point where a chemical shows neither stimulatory nor inhibitory effects. This,
unfortunately, is not true of Nitrosomonas. Growth of Nitrosomonas is greatly
inhibited (about 60%) by Copper concentrations of 0.20 ppm.
Growth of Nitrosomonas europaea in batch and continuous culture (Skinner & Walker 1960)
Copper was also found to be one of the most toxic metals to heterotrophic bacteria in aquatic environments.
Sadly, company #1 is partially correct in
claiming that their ionizer “destroys bacteria”.
In
conclusion, based on the above data, we arrive at these facts-
-Ionizers can indeed control and, in some
instances, eliminate many species of algae.
-Within the manufacturers’ suggested range of
use, 0 – 25/30 mg/L, neither Koi or Goldfish should exhibit any immediate
effects of Copper toxicity. It has been shown that Koi fry can tolerate levels
of 1.00 mg/L. Due to lack of any meaningful research, long term (chronic)
effects are unknown.
-Copper at low levels is extremely toxic to
aquatic stages of most amphibians.
-Most microorganisms exhibit toxic effects of
Copper at extremely low levels and, where mortality does not occur, the effects
are compounded in second generations.
-The effects of relatively low (.20 ppm)
Copper levels on one of the main species involved in Nitrogen conversion has
the potential to cause major problems in the form of Ammonia spikes.
Considering
the whole picture regarding the impact that an Ionizer may have on an aquatic
eco-system, this author has no intention of availing himself of its use. There
are other effective and absolutely safe ways of controlling and/or eliminating
algae. You, the reader, may feel differently. After all, it’s your Pond and
your fish.
You
be the judge!
_______________
Update Nov. 29, 2012
There has long been a dearth of information regarding the
toxicity level of Copper in Koi (Cyprinus carpio). Finally some figures are
being established by scientific research.
By
Hoseini,
Seyyed Morteza;
Hosseini,
Seyed Abbas;
Soudagar,
Mohammad), Carp exposed to 10 mg/L Copper exhibited mortality rates of
21.7 ± 7.6 % at 120 hours and 61.7 ± 10.4 %
at 168 hours. Although this level of Copper is 40 times the (claimed) maximum
levels generated by ionizers, I feel that it is safe to infer, because Cu is a
bio-accumulate, that depending on the usage (level settings and duration of
these settings) of ionizers, that Koi/Carp would exhibit physiological and
behavioral signs of toxicity much quicker than was originally thought….months
instead of years. Hopefully more definitive figures will be forthcoming.
______________
Update July 8, 2014
In this recent research paper - Acute effect of copper exposure on serum biochemical characteristics of common carp (Cyprinus carpio L.), Melika Ghelichpour the effects of low level exposure to Copper were markedly detectable.
"Effects of ambient copper was investigated on serum stress markers, sodium and enzyme levels in Common carp (Cyprinus carpio L.) over a 14-d exposure period. Fish were exposed to 0, 25 and 100 microg L-1 copper (as copper sulfate) and blood was sampled at 0, 3, 7 and 14 d after exposure. Serum profile was significantly affected by copper concentration, sampling time and their interaction. Increase in serum levels of cortisol, glucose, alanine aminotransferase and aspartate aminotransferase and decrease in serum sodium levels were observed in both copper-exposed groups, 3 d after copper exposure, which lasted until the end of the experiment. It is concluded that copper exposure causes stress response and sodium loss in common carp. Likewise alanine aminotransferase and aspartate aminotransferase increase after exposure which might be as results of either tissue damage or stress."
Note: Copper Sulfate readily disassociates in water producing Copper ions. The physiological effects would be the same with an ionizer.
_________________
UPDATE June 23, 2015
Just released article
“ Health status of two ornamental fishes Poecilia reticulatae
(Guppy) and Carassius auratus auratus (Gold fish) following exposure
to therapeutic levels of Copper sulphate
M.H.B.W.M.D.N.H. Wickramasinghe* and A. Pathiratne”
…indicates that gill damage occurs in Goldfish at Copper
levels of 0.10 mg/L and may not be completely reversible at levels of 0.30 mg/L
and recommends that “precautions should be taken especially with the high
concentration of CuSO4 (Copper) as it may lead to transient ill health conditions in the
exposed fishes.”
