I can confirm the following information has been provided by the farms in Singapore who supply plants to the UK market. This information has been consulted on with respected persons in the UK industry.
Phytosanitary certification requires the plants to be free of pests and disease prior to export to the receiving country. The methods applied are as follows – information supplied per farm:
Our Asian plants are dipped in BUPROFEZIN (0.01%) & TRICHLORFON (0.08%) for the duration 120 minutes. We now exclusively source plants from Oriental Aquarium (S) Pte Ltd.
We used to provide plants from multiple Asian sources, but this has stopped following the disclosure of their pesticide use. The details are below:
Our supplier for standard plants dip in IMIDACLOPRID 18.3% V/V (0.005%) for 45 minutes (South Island no longer supply PlantedTanks).
Our second supplier for standard plant range dip in IMIDACLOPRID 18.3% V/V (0.005%) for 60 minutes (Liberty no longer supply PlantedTanks).
All farms advise that following exposure to the above chemicals, all plants are rinsed in freshwater – although they do not advise for how long. The advice from the farms for end customers is that they quarantine the plants in a plant only system before introducing to a tank populated with inverts & crustaceans etc.
Plants that are classed as overstock remain in our tanks until sold – this can be up to 6 days and can be purchased in our shop premises.
Reference has been made against all three chemicals detailed above, and as such we will now produce a recommendation sheet for our customers to use about plant quarantine.
Our recommendation will be that all plants from ANY supplier should be quarantined in Alkaline water for a minimum of 2 hours to 48 hours, then finally rinsed in tap water prior to addition to any tank with livestock present. Please note - we say a MINIMUM of 2 hours and suggest that 48 hours be better... don't forget to perform water changes when appropriate.
Alkaline water can be easily made using caustic soda or hydrogen peroxide mixed with water until the pH reaches 8.5. Remember to wash your plants in tap water as a final preparation before they go in your tank.
Reference has been made from:
http://pmep.cce.cornell.edu/profiles/ex ... n-ext.html
What has been specifically noticed is that
Trichlorofon is a particularly aggressive organophosphate pesticide. It is however can be detected in acidic water up to 526 days at 20C at pH5.0. That said – if alkaline water is used – pH8.5 then this product is 99% degraded within 2 hours.
Buprofezin is an insecticide – specifically an acaricide. It is not approved for use in the UK. The degradation half life is 50 days within soil and 16 days in water at pH7.0, 20C. This product specifically requires extended quarantine of at least 48 hours.
Imidacloprid is a systemic insecticide. It has a 3 hour half life in water pH neutral. It is known to be non toxic to fish, moderately toxic to crustaceans and highly toxic to invertebrates. The addition of this chemical to water reputedly degrades to CO2 as a side effect of the degradation in the presence of light.
SPECIFIC INFORMATION REGARDING SHRIMPS AND THE CHEMICALS DETAILED ABOVE
The following information was sourced by DW1305 a member of the UKAPS (www.ukaps.org)
Chlorophos insecticides are highly toxic organophosphate insecticides and cause damage to the nervous system ("anti-cholinesterase compounds"), so you would expect to see shrimp "staggering" about before dying. They are non-systemic, so shouldn't end up in the plant.
BUPROFEZIN It is an "Insect Growth Regulator", which means that it would stop crustaceans shedding their skins (it interrupts chitin synthesis), so it could cause death in the longer term.
IMIDACLOPRID, is a systemic, neonicotinoid insecticide and would remain in the plant for some time. Neonicotonoids are suspected of causing a lot of the decline of insect biodiversity in Europe and the USA, and a really not the sort of compound you would want anywhere near your shrimps.
IMIDACLOPRID has low toxicity to fish, but is highly toxic to crustaceans, in conc. as low as 1 ppb for Mysis shrimp. "Products containing imidacloprid may be very toxic to aquatic invertebrates." "The half-life in water is much greater than 31 days at pH 5, 7 and 9". from Kidd & James (1991) The Agrochemicals Handbook, Third Edition. Royal Society of Chemistry Information Services, Cambridge, UK.
Most studies show that these neonicotinoid pesticides are extremely persistent. "The solubility of imidacloprid in water is relatively high: 0.51 g/l, and its octanol-water partitioning coefficient is quite low: log Kow = 0.57 (Gupta et al., 2002). Imidacloprid is generally persistent in water, and not easily biodegradable (Tišler et al., 2009). Indeed, Overmyer et al. (2005) found no significant differences in imidacloprid concentration in water over a 48-hour experiment, and Roberts & Hutson (1999) reported that it is likely to remain in the water column in aquatic systems, and has an aerobic sediment and water DT50 of 30 to 162 days (time for 50% decline of the initial pesticide concentration, or half-life time). More details here: <http://igitur-archive.library.uu.nl/student-theses/2010-0722-200330/MSc%20Thesis%20Tessa%20van%20Dijk.pdf>".
Kreutzweiser et al. (2009) in "Imidacloprid in leaves from systemically treated trees may inhibit litter breakdown by non-target invertebrates". Ecotoxicology and Environmental Safety 72:4, pp 1053–1057 said: Abs. "Imidacloprid is a systemic insecticide that is used in trees to control several invasive, wood-boring insect pests in North America. Applications to deciduous trees result in foliar concentrations of imidacloprid that could pose a risk of harm to non-target decomposer invertebrates when autumn-shed leaves fall to forest floors or adjacent water bodies. ........ There was no significant preferential feeding on non-contaminated leaves in selection microcosms indicating that the invertebrates could not detect and avoid imidacloprid-containing leaves. Mass loss and area consumed of both imidacloprid-containing and natural leaves in selection microcosms were significantly less than in control microcosms, indicating a sub-lethal feeding inhibition effect from consumption of leaf material at realistic field concentrations of 18–30 μg/g fresh weight. Our results indicate that imidacloprid at realistic concentrations in leaves can inhibit leaf litter breakdown through adverse sub-lethal effects on decomposer invertebrates."