Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
Martin,
I'm not dead certain of my memory either (experts please help), but if I recall
correctly (and if the source(s) was/were correct), many "weeds" are
non-mycorrhizal or facultatively so. I'm not sure of the Chenopodiaceae, but
they seem to be notorious hyperaccumulators (as Popeye was famously aware), and
I don't know whether or not they are ever mycorrhizal and what difference it
may make.
Has anybody really sorted this out? I don't want to hit the books, but if I did
I would dig out Stebbins' "The Genetics of Colonizing Species." Sounds like a
peach of an idea for a dissertation.
WT
PS: The evolutionary history of mycorrhizal associations might hold a clue.
What is it about root physiology that keeps some minerals in and some out?
Semipermeable membranes? Something else (too)? How is the amount limited?
Osmotic potential? Help!
- Original Message -
From: Martin Meiss
To: Wayne Tyson
Cc: ECOLOG-L@listserv.umd.edu
Sent: Wednesday, April 20, 2011 10:31 AM
Subject: Re: [ECOLOG-L] where do edible plants retain lead and other
contaminants?
Wayne,
Your comment on mineral uptake by the mustard family reminded me
(correctly, I hope) that the the cruciferae are one family that does not use
mycorrhizae to mediate mineral uptake. Maybe the mycorrhizal associations
account for some of the variability in heavy-metal uptake in other families.
Martin
2011/4/16 Wayne Tyson
The original post may be related to the "eat the weeds" movement, one I
have long considered a good idea while suffering no illusions that it will have
any real impact upon the weed "problem."
I eat weeds because I prefer them to most of their highly developed or
CMO'd relatives. The weeds often, in addition to being more tasty, contain more
nutrition than their cultivated cousins. Chenopodium album, for example, a
common roadside weed, is one of my favorites. It is an "accumulator" (what
plant isn't), containing a lot of iron (iron is a vital nutrient; it also is a
poison--dosage is important). I do, however, pay attention to the substrate
upon which they are growing. I prefer hillsides to stream bottoms unless I know
the watershed is pretty free of contamination. Stream bottoms, especially those
into which contaminants, often in the form of raw sewage drain, often contain
the "best" crops of the lushest weeds. In my ignorance of the specifics, I rely
upon the precautionary principle, "the solution to pollution is dilution," and
a smidgen of knowledge (which we all know can often get one into more trouble
than ignorance), and perhaps some myths I have unwittingly adsorbed (or worse,
absorbed) along the way. I avoid roadsides and vacant lots of unknown history
too. I trust my own ignorance more than that of agribusiness, but that's far
from perfect.
WT
- Original Message ----- From: "malcolm McCallum"
To:
Sent: Saturday, April 16, 2011 7:10 AM
Subject: Re: [ECOLOG-L] where do edible plants retain lead and other
contaminants?
Wayne brings up a good point.
The bioavailability of toxic compounds, including metals is affected
by many things among which pH can be one.
In fact, the issue of TMDLs in the clean water act is based on problem
that each stream has its own water chemistry and organic load. This
causes us to require specific total maximum daily loads (TMDLs) of
each compound for each stream (or portions thereof). TMDLs were
supposed to be completed for surface waters in most states a long time
ago, unfortunately the process is not done everywhere!
Malcolm
On Fri, Apr 15, 2011 at 9:03 PM, Wayne Tyson wrote:
Ecolog:
This rings a vague bell for me too. There was some work done in the
British
Isles (Scotland) on very crisp ecotones across pH differences using one
grass species. Also, I seem to recall that the Dutch were using willows
that
were supposed to be hyperaccumulators and they were burning them for fuel,
then disposing of (or "mining") the heavy-metal "laden" ash. There is, of
course, considerable literature on "phytoprospecting." I, too, would like
to
be brought up to date in this area, and educated on the particulars. For
example, I would like to know just how accumulation or "rejection"
functions, and what processes are involved. For example, how does pH
affect
the rate and amount of absorption? What other chemical and physiological
processes are involved? Why are some heavy metals (chromium, selenium,
arsenic, etc.) apparently readily absorbed (by the Chenopodiaceae, for
example--and the mustard family), and lead apparently not? Is it as simple
as semipermeable membranes, w
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
Wayne, Your comment on mineral uptake by the mustard family reminded me (correctly, I hope) that the the cruciferae are one family that does not use mycorrhizae to mediate mineral uptake. Maybe the mycorrhizal associations account for some of the variability in heavy-metal uptake in other families. Martin 2011/4/16 Wayne Tyson > The original post may be related to the "eat the weeds" movement, one I > have long considered a good idea while suffering no illusions that it will > have any real impact upon the weed "problem." > > I eat weeds because I prefer them to most of their highly developed or > CMO'd relatives. The weeds often, in addition to being more tasty, contain > more nutrition than their cultivated cousins. Chenopodium album, for > example, a common roadside weed, is one of my favorites. It is an > "accumulator" (what plant isn't), containing a lot of iron (iron is a vital > nutrient; it also is a poison--dosage is important). I do, however, pay > attention to the substrate upon which they are growing. I prefer hillsides > to stream bottoms unless I know the watershed is pretty free of > contamination. Stream bottoms, especially those into which contaminants, > often in the form of raw sewage drain, often contain the "best" crops of the > lushest weeds. In my ignorance of the specifics, I rely upon the > precautionary principle, "the solution to pollution is dilution," and a > smidgen of knowledge (which we all know can often get one into more trouble > than ignorance), and perhaps some myths I have unwittingly adsorbed (or > worse, absorbed) along the way. I avoid roadsides and vacant lots of unknown > history too. I trust my own ignorance more than that of agribusiness, but > that's far from perfect. > > WT > > > - Original Message ----- From: "malcolm McCallum" < > malcolm.mccal...@herpconbio.org> > > To: > Sent: Saturday, April 16, 2011 7:10 AM > > Subject: Re: [ECOLOG-L] where do edible plants retain lead and other > contaminants? > > > Wayne brings up a good point. > > The bioavailability of toxic compounds, including metals is affected > by many things among which pH can be one. > In fact, the issue of TMDLs in the clean water act is based on problem > that each stream has its own water chemistry and organic load. This > causes us to require specific total maximum daily loads (TMDLs) of > each compound for each stream (or portions thereof). TMDLs were > supposed to be completed for surface waters in most states a long time > ago, unfortunately the process is not done everywhere! > > Malcolm > > On Fri, Apr 15, 2011 at 9:03 PM, Wayne Tyson wrote: > >> Ecolog: >> >> This rings a vague bell for me too. There was some work done in the >> British >> Isles (Scotland) on very crisp ecotones across pH differences using one >> grass species. Also, I seem to recall that the Dutch were using willows >> that >> were supposed to be hyperaccumulators and they were burning them for fuel, >> then disposing of (or "mining") the heavy-metal "laden" ash. There is, of >> course, considerable literature on "phytoprospecting." I, too, would like >> to >> be brought up to date in this area, and educated on the particulars. For >> example, I would like to know just how accumulation or "rejection" >> functions, and what processes are involved. For example, how does pH >> affect >> the rate and amount of absorption? What other chemical and physiological >> processes are involved? Why are some heavy metals (chromium, selenium, >> arsenic, etc.) apparently readily absorbed (by the Chenopodiaceae, for >> example--and the mustard family), and lead apparently not? Is it as simple >> as semipermeable membranes, whether or not they are soluble and under what >> conditions? Is something going on in the rhizosphere that evades some >> analytical procedures? >> >> WT >> >> >> - Original Message - From: "Martin Meiss" >> To: >> Sent: Friday, April 15, 2011 9:04 AM >> Subject: Re: [ECOLOG-L] where do edible plants retain lead and other >> contaminants? >> >> >> A long time ago, when I was learning about plant ecotypes, I heard of >> research on the adaptation of plants to high lead levels found in piles of >> mine tailings. If I remember correctly, local races of plants were forming >> that were able to adapt to toxic soils. This raises these questions: if >> plants ARE NOT taking up the heavy metals, what is the mode of toxicity? >> (Are ions in the soil blocking the uptak
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
The original post may be related to the "eat the weeds" movement, one I have long considered a good idea while suffering no illusions that it will have any real impact upon the weed "problem." I eat weeds because I prefer them to most of their highly developed or CMO'd relatives. The weeds often, in addition to being more tasty, contain more nutrition than their cultivated cousins. Chenopodium album, for example, a common roadside weed, is one of my favorites. It is an "accumulator" (what plant isn't), containing a lot of iron (iron is a vital nutrient; it also is a poison--dosage is important). I do, however, pay attention to the substrate upon which they are growing. I prefer hillsides to stream bottoms unless I know the watershed is pretty free of contamination. Stream bottoms, especially those into which contaminants, often in the form of raw sewage drain, often contain the "best" crops of the lushest weeds. In my ignorance of the specifics, I rely upon the precautionary principle, "the solution to pollution is dilution," and a smidgen of knowledge (which we all know can often get one into more trouble than ignorance), and perhaps some myths I have unwittingly adsorbed (or worse, absorbed) along the way. I avoid roadsides and vacant lots of unknown history too. I trust my own ignorance more than that of agribusiness, but that's far from perfect. WT - Original Message - From: "malcolm McCallum" To: Sent: Saturday, April 16, 2011 7:10 AM Subject: Re: [ECOLOG-L] where do edible plants retain lead and other contaminants? Wayne brings up a good point. The bioavailability of toxic compounds, including metals is affected by many things among which pH can be one. In fact, the issue of TMDLs in the clean water act is based on problem that each stream has its own water chemistry and organic load. This causes us to require specific total maximum daily loads (TMDLs) of each compound for each stream (or portions thereof). TMDLs were supposed to be completed for surface waters in most states a long time ago, unfortunately the process is not done everywhere! Malcolm On Fri, Apr 15, 2011 at 9:03 PM, Wayne Tyson wrote: Ecolog: This rings a vague bell for me too. There was some work done in the British Isles (Scotland) on very crisp ecotones across pH differences using one grass species. Also, I seem to recall that the Dutch were using willows that were supposed to be hyperaccumulators and they were burning them for fuel, then disposing of (or "mining") the heavy-metal "laden" ash. There is, of course, considerable literature on "phytoprospecting." I, too, would like to be brought up to date in this area, and educated on the particulars. For example, I would like to know just how accumulation or "rejection" functions, and what processes are involved. For example, how does pH affect the rate and amount of absorption? What other chemical and physiological processes are involved? Why are some heavy metals (chromium, selenium, arsenic, etc.) apparently readily absorbed (by the Chenopodiaceae, for example--and the mustard family), and lead apparently not? Is it as simple as semipermeable membranes, whether or not they are soluble and under what conditions? Is something going on in the rhizosphere that evades some analytical procedures? WT ----- Original Message ----- From: "Martin Meiss" To: Sent: Friday, April 15, 2011 9:04 AM Subject: Re: [ECOLOG-L] where do edible plants retain lead and other contaminants? A long time ago, when I was learning about plant ecotypes, I heard of research on the adaptation of plants to high lead levels found in piles of mine tailings. If I remember correctly, local races of plants were forming that were able to adapt to toxic soils. This raises these questions: if plants ARE NOT taking up the heavy metals, what is the mode of toxicity? (Are ions in the soil blocking the uptake of needed substances?) What is the mechanism of resistance that was evolving? If it involved the blocking of uptake of lead and other metals, that implies that other, non-adapted plants DO take them up. Can any one comment on this aspect of the issue? Martin M. Meiss 2011/4/15 Judy Che-Castaldo Hi Ben, In general you are unlikely to find lead in the shoots of plants, because it is not very soluble and most plants exclude heavy metals. The edible plants that may have Pb would likely be leafy vegetables (grown close to the ground) and root vegetables (as mentioned earlier) because of the associated soil particles containing Pb. There are some plants that uptake heavy metals into their shoots but few for Pb, and even those may only do so under rare circumstances (such as phosphorous deficiency - Chaney 2007 J. Environ. Qual. 36:1429–1443).. If you are interested in other contaminants you can look into the metal hyperaccumulation li
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
Wayne brings up a good point. The bioavailability of toxic compounds, including metals is affected by many things among which pH can be one. In fact, the issue of TMDLs in the clean water act is based on problem that each stream has its own water chemistry and organic load. This causes us to require specific total maximum daily loads (TMDLs) of each compound for each stream (or portions thereof). TMDLs were supposed to be completed for surface waters in most states a long time ago, unfortunately the process is not done everywhere! Malcolm On Fri, Apr 15, 2011 at 9:03 PM, Wayne Tyson wrote: > Ecolog: > > This rings a vague bell for me too. There was some work done in the British > Isles (Scotland) on very crisp ecotones across pH differences using one > grass species. Also, I seem to recall that the Dutch were using willows that > were supposed to be hyperaccumulators and they were burning them for fuel, > then disposing of (or "mining") the heavy-metal "laden" ash. There is, of > course, considerable literature on "phytoprospecting." I, too, would like to > be brought up to date in this area, and educated on the particulars. For > example, I would like to know just how accumulation or "rejection" > functions, and what processes are involved. For example, how does pH affect > the rate and amount of absorption? What other chemical and physiological > processes are involved? Why are some heavy metals (chromium, selenium, > arsenic, etc.) apparently readily absorbed (by the Chenopodiaceae, for > example--and the mustard family), and lead apparently not? Is it as simple > as semipermeable membranes, whether or not they are soluble and under what > conditions? Is something going on in the rhizosphere that evades some > analytical procedures? > > WT > > > - Original Message - From: "Martin Meiss" > To: > Sent: Friday, April 15, 2011 9:04 AM > Subject: Re: [ECOLOG-L] where do edible plants retain lead and other > contaminants? > > > A long time ago, when I was learning about plant ecotypes, I heard of > research on the adaptation of plants to high lead levels found in piles of > mine tailings. If I remember correctly, local races of plants were forming > that were able to adapt to toxic soils. This raises these questions: if > plants ARE NOT taking up the heavy metals, what is the mode of toxicity? > (Are ions in the soil blocking the uptake of needed substances?) What is > the mechanism of resistance that was evolving? If it involved the blocking > of uptake of lead and other metals, that implies that other, non-adapted > plants DO take them up. > Can any one comment on this aspect of the issue? > > Martin M. Meiss > > 2011/4/15 Judy Che-Castaldo > >> Hi Ben, >> In general you are unlikely to find lead in the shoots of plants, because >> it >> is not very soluble and most plants exclude heavy metals. The edible >> plants >> that may have Pb would likely be leafy vegetables (grown close to the >> ground) and root vegetables (as mentioned earlier) because of the >> associated >> soil particles containing Pb. >> >> There are some plants that uptake heavy metals into their shoots but few >> for >> Pb, and even those may only do so under rare circumstances (such as >> phosphorous deficiency - Chaney 2007 J. Environ. Qual. 36:1429–1443). If >> you are interested in other contaminants you can look into the metal >> hyperaccumulation literature. Many of these plants are in the mustard >> family but probably are not normally eaten. >> >> best, >> Judy >> >> >> Judy Che-Castaldo >> BEES program, Biology Dept. >> University of Maryland >> (301)351-8290 >> http://www.life.umd.edu/grad/BEES/students/che.html >> > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1204 / Virus Database: 1435/3511 - Release Date: 03/16/11 > Internal Virus Database is out of date. > -- Malcolm L. McCallum Managing Editor, Herpetological Conservation and Biology "Peer pressure is designed to contain anyone with a sense of drive" - Allan Nation 1880's: "There's lots of good fish in the sea" W.S. Gilbert 1990's: Many fish stocks depleted due to overfishing, habitat loss, and pollution. 2000: Marine reserves, ecosystem restoration, and pollution reduction MAY help restore populations. 2022: Soylent Green is People! Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message.
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
Ecolog: This rings a vague bell for me too. There was some work done in the British Isles (Scotland) on very crisp ecotones across pH differences using one grass species. Also, I seem to recall that the Dutch were using willows that were supposed to be hyperaccumulators and they were burning them for fuel, then disposing of (or "mining") the heavy-metal "laden" ash. There is, of course, considerable literature on "phytoprospecting." I, too, would like to be brought up to date in this area, and educated on the particulars. For example, I would like to know just how accumulation or "rejection" functions, and what processes are involved. For example, how does pH affect the rate and amount of absorption? What other chemical and physiological processes are involved? Why are some heavy metals (chromium, selenium, arsenic, etc.) apparently readily absorbed (by the Chenopodiaceae, for example--and the mustard family), and lead apparently not? Is it as simple as semipermeable membranes, whether or not they are soluble and under what conditions? Is something going on in the rhizosphere that evades some analytical procedures? WT - Original Message - From: "Martin Meiss" To: Sent: Friday, April 15, 2011 9:04 AM Subject: Re: [ECOLOG-L] where do edible plants retain lead and other contaminants? A long time ago, when I was learning about plant ecotypes, I heard of research on the adaptation of plants to high lead levels found in piles of mine tailings. If I remember correctly, local races of plants were forming that were able to adapt to toxic soils. This raises these questions: if plants ARE NOT taking up the heavy metals, what is the mode of toxicity? (Are ions in the soil blocking the uptake of needed substances?) What is the mechanism of resistance that was evolving? If it involved the blocking of uptake of lead and other metals, that implies that other, non-adapted plants DO take them up. Can any one comment on this aspect of the issue? Martin M. Meiss 2011/4/15 Judy Che-Castaldo Hi Ben, In general you are unlikely to find lead in the shoots of plants, because it is not very soluble and most plants exclude heavy metals. The edible plants that may have Pb would likely be leafy vegetables (grown close to the ground) and root vegetables (as mentioned earlier) because of the associated soil particles containing Pb. There are some plants that uptake heavy metals into their shoots but few for Pb, and even those may only do so under rare circumstances (such as phosphorous deficiency - Chaney 2007 J. Environ. Qual. 36:1429–1443). If you are interested in other contaminants you can look into the metal hyperaccumulation literature. Many of these plants are in the mustard family but probably are not normally eaten. best, Judy Judy Che-Castaldo BEES program, Biology Dept. University of Maryland (301)351-8290 http://www.life.umd.edu/grad/BEES/students/che.html - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1204 / Virus Database: 1435/3511 - Release Date: 03/16/11 Internal Virus Database is out of date.
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
A long time ago, when I was learning about plant ecotypes, I heard of research on the adaptation of plants to high lead levels found in piles of mine tailings. If I remember correctly, local races of plants were forming that were able to adapt to toxic soils. This raises these questions: if plants ARE NOT taking up the heavy metals, what is the mode of toxicity? (Are ions in the soil blocking the uptake of needed substances?) What is the mechanism of resistance that was evolving? If it involved the blocking of uptake of lead and other metals, that implies that other, non-adapted plants DO take them up. Can any one comment on this aspect of the issue? Martin M. Meiss 2011/4/15 Judy Che-Castaldo > Hi Ben, > In general you are unlikely to find lead in the shoots of plants, because > it > is not very soluble and most plants exclude heavy metals. The edible > plants > that may have Pb would likely be leafy vegetables (grown close to the > ground) and root vegetables (as mentioned earlier) because of the > associated > soil particles containing Pb. > > There are some plants that uptake heavy metals into their shoots but few > for > Pb, and even those may only do so under rare circumstances (such as > phosphorous deficiency - Chaney 2007 J. Environ. Qual. 36:1429–1443). If > you are interested in other contaminants you can look into the metal > hyperaccumulation literature. Many of these plants are in the mustard > family but probably are not normally eaten. > > best, > Judy > > > Judy Che-Castaldo > BEES program, Biology Dept. > University of Maryland > (301)351-8290 > http://www.life.umd.edu/grad/BEES/students/che.html >
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
Hi Ben, In general you are unlikely to find lead in the shoots of plants, because it is not very soluble and most plants exclude heavy metals. The edible plants that may have Pb would likely be leafy vegetables (grown close to the ground) and root vegetables (as mentioned earlier) because of the associated soil particles containing Pb. There are some plants that uptake heavy metals into their shoots but few for Pb, and even those may only do so under rare circumstances (such as phosphorous deficiency - Chaney 2007 J. Environ. Qual. 36:14291443). If you are interested in other contaminants you can look into the metal hyperaccumulation literature. Many of these plants are in the mustard family but probably are not normally eaten. best, Judy Judy Che-Castaldo BEES program, Biology Dept. University of Maryland (301)351-8290 http://www.life.umd.edu/grad/BEES/students/che.html
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
Just like animals, plants accumulate metals and similar toxins throughout depending on the metal. Many things are accumulated in the roots, but also elsewhere. For example, in an unpublished study we were doing on an oxbow lake adjacent to the Red River we found Chromium and several other metals in the leaves and stems of water plants. This ability of plants to remove certain compounds from the environment stimulated the idea of phytoremediation to remove these things from soils and water. Water soluble contaminants have a more complex fate in plants because they can enter and leave with water. However, they also have the capacity to more evenly distribute throughout the plant depending on their molecular size. Further, plants due to their use of photosynthesis have an extremely well developed antioxidant enzyme system which provides them with a powerful ability to detoxify compounds and deal with free radical damage generated by contaminants. Consequently, plants in some cases can break down these compounds very effectively break down these compounds. Many herbicides in particular attack either the cell membranes (paraquate like herbicides), the photosynthetic pathways, or growth and lipid production of the meristems. There are others. I don't know a whole lot about plant toxicology, however, if you want to learn more I would investigate the phytoremediation literature and the literature on herbicide action in plants. The agronomy literature will tell you a lot obout this too. Malcolm McCallum On Wed, Apr 13, 2011 at 11:20 PM, Ben Bowman wrote: > I am looking for information about where different types of plants absorb and > retain heavy metals and other toxins. > > I would like to compile a list of edible plants that are safe to propagate and > consume despite soil contamination. This could include plants that absorb > toxins but deposit them in isolated areas. I have been told, for example, that > tree fruits can be planted in lead contaminated soil, because lead never rises > high enough in trees to wind up in their fruits. Or, if you know of such a > list already out there, I would love to see it! > > I think that lead is the most common toxin in many urban areas, so I am > particularly interested in where plants deposit lead, but I would appreciate > information on how/where they hold onto other toxins as well. > > Thanks for your help, > Ben > -- Malcolm L. McCallum Managing Editor, Herpetological Conservation and Biology "Peer pressure is designed to contain anyone with a sense of drive" - Allan Nation 1880's: "There's lots of good fish in the sea" W.S. Gilbert 1990's: Many fish stocks depleted due to overfishing, habitat loss, and pollution. 2000: Marine reserves, ecosystem restoration, and pollution reduction MAY help restore populations. 2022: Soylent Green is People! Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message.
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
>From the University of Minnesota Extension Service: http://www.extension.umn.edu/distribution/horticulture/DG2543.html Might be a bit better than "I have been told ." mcneely Ben Bowman wrote: > I am looking for information about where different types of plants absorb and > retain heavy metals and other toxins. > > I would like to compile a list of edible plants that are safe to propagate > and > consume despite soil contamination. This could include plants that absorb > toxins but deposit them in isolated areas. I have been told, for example, > that > tree fruits can be planted in lead contaminated soil, because lead never > rises > high enough in trees to wind up in their fruits. Or, if you know of such a > list already out there, I would love to see it! > > I think that lead is the most common toxin in many urban areas, so I am > particularly interested in where plants deposit lead, but I would appreciate > information on how/where they hold onto other toxins as well. > > Thanks for your help, > Ben -- David McNeely
Re: [ECOLOG-L] where do edible plants retain lead and other contaminants?
Most plants put and store most of the metals in their roots. But the percentage varies and you would have to look it up for particular species and a particular metal. So plants where roots are eaten would not be advised, but usually there would be much less in the stems, leaves or fruits. > I am looking for information about where different types of plants absorb > and > retain heavy metals and other toxins. > > I would like to compile a list of edible plants that are safe to propagate > and > consume despite soil contamination. This could include plants that absorb > toxins but deposit them in isolated areas. I have been told, for example, > that > tree fruits can be planted in lead contaminated soil, because lead never > rises > high enough in trees to wind up in their fruits. Or, if you know of such a > list already out there, I would love to see it! > > I think that lead is the most common toxin in many urban areas, so I am > particularly interested in where plants deposit lead, but I would > appreciate > information on how/where they hold onto other toxins as well. > > Thanks for your help, > Ben >
[ECOLOG-L] where do edible plants retain lead and other contaminants?
I am looking for information about where different types of plants absorb and retain heavy metals and other toxins. I would like to compile a list of edible plants that are safe to propagate and consume despite soil contamination. This could include plants that absorb toxins but deposit them in isolated areas. I have been told, for example, that tree fruits can be planted in lead contaminated soil, because lead never rises high enough in trees to wind up in their fruits. Or, if you know of such a list already out there, I would love to see it! I think that lead is the most common toxin in many urban areas, so I am particularly interested in where plants deposit lead, but I would appreciate information on how/where they hold onto other toxins as well. Thanks for your help, Ben
