Disposing of old pink anti-freeze

thinwater said:
The point, people, is that marine toxicity is TOTALLY different from human toxicity. They sell zinc pills at the drugs store--you need it--but we know it is lethal to marine life.
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This is certainly not my field and I'll happily demur if it is yours, but the above seems something of an overstatement compared to this from your own Fish & Wildlife service:

"Zinc is an essential elelement for all living organisms but elevated levels of zinc may be harmful near zinc-contaminated sites...in contrast to its toxicity to sensitive aquatic organisms, zinc is relatively non-toxic to birds an mammals".
http://www.usbr.gov/niwqp/guidelines/pdf/Zinc.pdf

"
 
macd said:
This is certainly not my field and I'll happily demur if it is yours, but the above seems something of an overstatement compared to this from your own Fish & Wildlife service:

"Zinc is an essential elelement for all living organisms but elevated levels of zinc may be harmful near zinc-contaminated sites...in contrast to its toxicity to sensitive aquatic organisms, zinc is relatively non-toxic to birds an mammals".
http://www.usbr.gov/niwqp/guidelines/pdf/Zinc.pdf

"
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Surely your quotation is in total agreement with thinwater's? :confused:

Richard
 
macd said:
thinwater: "[zinc] is lethal to marine life".
US Fish & Wildlife: "Zinc is an essential element for all living organisms".

I don't see that as total agreement. The expression I used (which was a suggestion, not an assertion) was "something of an overstatement".
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"in contrast to its toxicity to sensitive aquatic organisms" .... seems to me to meet thinwater's observation:).

Richard
 
RichardS said:
"in contrast to its toxicity to sensitive aquatic organisms" .... seems to me to meet thinwater's observation:).
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Rather selective. And, of course, it's clearly a question of degree: the report talks of "elevated levels". Yes, clearly zinc can be toxic to marine (and non-marine) organisms, but I simply don't see the absolute statement that zinc is toxic as being compatible with zinc's being "essential" without qualification. (In the same way that digitalis, to take one example, can be fatal, yet is actually a prescribed medicine.)

From the tone of his post, this is a subject on which thinwater may well have some authority, and I'd invite him to make that qualification...because I'd like to know more.
 
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AntarcticPilot said:
Isn't antifreeze often implicated in poisoning of cats and dogs (and sometimes children, when it has been stored in the wrong bottle within reach of toddlers)? Of course, they have vastly different physiologies to fish, but antifreeze certainly is harmful at pretty low doses for some organisms.
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Ethylene Glycol (permanent antifreeze,prestone,etc) that is used in the closed cooling systems of vehicles & boats is dangerously toxic to humans & animals. It smells & tastes sweet & has killed many pets & small animals as well as humans who have injested it. Treat it with respect & dispose of it "properly"-do not leave it lying around-it is poisonous in small quantities.

Propylene Glycol is used as a temporary antifreeze for seasonal protection of water systems. It is also used in many food products per the link in my previous post & is "GRA" rated-safe for consumption in small quantities-ie: not poisonous.

The colour is not a proof of whether an antifreeze is ethylene or propylene.

Cheers/ Len :)
 
Obviously I oversimplified when I referred to zinc as "lethal to marine life." In my day job I used to design plants to remove zinc from wastewater (refineries, including glycols--I'm not guessing). Thus, we know that...

* Zinc is an active ingredient in many anti-fouling paints, sometimes in combination with copper.
* Discharge limits on zinc in treated sewage are 1-2 orders of magnitude lower than the limit in drinking water. The drinking water limit is only for taste (makes it taste muddy).
* Very few marine organisms can tolerate more than 0.02-0.05 ppm zinc for more than a week, mostly less.

In fact, in a marine environment, the most dangerous parts of used antifreeze and oily wastewater is generally the dissolved metals, zinc being one of the worst and most common. Zinc (ZDP) is a very common additive, and there are many zinc alloys in machines.

Yes, unlike arsenic, where none is needs and every bit is bad, there is some requirement. The same is true of copper, even in marine organisms. But that amount is VERY small. Totally off topic, but the point is that toxicity is very organism-specific.

This, from a UK publication:
Mance and Yates (1984) proposed an EQS (for the protection of saltwater life) of 40 µg l-1 (expressed as a dissolved annual average concentration), which is currently adopted in UK legislation (HMSO 1989). The EQS was established by applying an arbitrary factor of 4 to a 96 hour LC50 of 166 µg l-1 reported at that time for the mysid shrimp Mysidopsis bahia. However, following a review of more recent toxicity data, Hunt and Hedgecott (1992) proposed a more stringent EQS to DoE of 10 µg l-1. This value (also expressed a dissolved annual average) was based on the lowest, most reliable NOECs reported for a range of organisms (7 - 20 µg l-1).

Grimwood and Dixon (1997) reviewed data on the saltwater toxicity of zinc following the Hunt and Hedgecott review and found only one study had been reported that perhaps indicated higher toxicity to saltwater organisms. Exposing the calanoid copepod Temora stylifera to zinc chloride, Nipper et al (1993) reported 48 hour LC50s ranging from 30 - 40 µg l-1, following exposure in saltwater of salinity 28 - 32 ppt. In addition, an LC50 as low as 4 µg l-1 was reported on exposure in saltwater of 23 ppt salinity. However, the authors concluded that this value should be treated with caution as there was also an unacceptable level of mortality in the control organisms. NOECs were not determined, although since the LC50s are lower than those reported for any other copepod species, it is conceivable that the NOECs may also be lower.
 
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Thanks, thinwater. Much appreciated.
The research summaries are a bit over my head, although I can see that 'safe' limits may be revised downwards. Disposing of antifreeze by other means than dumping them in the sea seems easy enough (in developed countrys, at least). Do you have any idea of the implications for antifouls? And do eroding zinc anodes form part of this same picture?
 
No idea about antifouling.

I am currently duing some long term trials of about 40 anodes, Zn and Al, ocean and brackish. So far...

* Aluminum protects better (amps and potential).
* Aluminum erodes a little faster.
* Aluminum causes or allows more growth on running gear.
 
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