OK, so why am I showing you guys pics of my past three grows going to shit?!
BECAUSE I DO NOT WISH ANY OF THIS HAPPENING TO YOU GUYS!
Here is a word that was not new to me but never paid much attention to:
"OFF-GASSING"
There are some interesting study's out there regarding the impact of DBP (many plastics, spray glues, panda film etc. contain it) on plants in greenhouses with optimal environmental conditions for growth. Many growers will never experience this problem due to high air exchange, but once the room gets sealed the story changes
I think we need to reconsider the use of products containing DBP in our growing environment, especially when operating 'sealed' environments.
I wish that there would have been more info on this, it may have saved my last three grows lol.
Here is an excerpt from on of the study's:
"CHRONIC PLANT STUDY
Results
Visual injury was observed on all species, varying from chlorosis and necrosis, leaf crinkling to a total loss of colour in the leaves and needles. The variation in sensitivity between plant species was quantified on the basis of whole plant biomass (shoot plus root) in order to derive NOEC and EC10 values.
Interestingly, white clover was found to be more sensitive to
DBP than cabbage. Further details can be found in the PRI (2002) report and IUCLID.
PNECplant-air proposal
The PRI (2002) study is considered acceptable and useful for deriving a
PNECplant-air. Two different routes can be used for deriving the PNECplant-air: 1) the standard method (lowest NOEC/EC10 divided by assessment factor, and 2) statistical extrapolation with an additional assessment factor.
Using the lowest EC10 value, i.e. 0.33 µg/m3, and applying the standard factor of 10 would result in a
PNECplant-air of
0.03 µg/m3. Calculating the 5th percentile of the species sensitivity distribution (EC10 values for effects on total biomass) would result in a median (50% confidence interval) value of
0.2 µg/m3 (ETX, 1993). The 5th percentile estimation meets the statistical goodness-of-fit requirements (Anderson-Darling test for normality). Calculating 5th percentile values for either root or shoot biomass, rather than total biomass, results in nearly the same 5th percentile.
The problem now is that there is no guidance yet on deriving a plant-air
PNEC in the Technical Guidance Document (TGD) (EC, 2003b). The TGD focuses on the PNEC derivation for water, sediment and soil, but the assumptions etc. for those compartments may not directly hold for plants (airborne route). A number of considerations can be given here on the PNECplant-air derivation for
DBP:
1. the focus is only on deriving a
PNEC air for plants. This means that other taxonomic groups of the atmospheric compartment (e.g. insects) will remain beyond the scope of the PNEC. This implies that assessment factors may cover less ecosystem than normally for water, soil and sediment.
2. the TGD (2003b) criteria for using statistical extrapolation are not all met here (e.g. number of NOECs), but they may also not be relevant here as the focus is only on plants (see point 1). There is a fairly well coverage of plant diversity in the selected plant species, and, in addition, an acceptable goodness-of-fit is shown. One may speculate then about the introduction of an additional assessment factor. Such additional assessment factor should still cover species diversity (see point 3). It is highly uncertain, however, whether a factor of 2, 3 or 4 should then be used. An arbitrary factor of 3 on the current 5th percentile would, for example, yield a
PNEC of 0.07 µg/m3.
3. the focus in the tiered testing program, of which the PRI (2002) test is the last part, has been on sensitive species (Brassica in particular). This is supported by literature data. It should be noted, however, that the PRI (2002) test showed that white clover was even more sensitive than Brassica. Some factor is needed therefore for possible other, even more sensitive species than clover.
4. according to plant experts, the conditions in greenhouses, are very unfavourable to plants with respect to their sensitivity to toxicants. This due to optimal light and feeding conditions which optimise the exposure and therefore the
toxicity. Therefore the standard factor of 10 for extrapolating from laboratory tests to the field-situation may be argued here (lower factor).
Taking all these points into consideration, it is clear that a quantitative approach on the
PNEC derivation would be very difficult in this case. The standard assessment factor of 10 is most probably too high, but should it then be 4, 6 or 7.5? The same is true for the additional assessment factor on the 5th percentile. It is pragmatically proposed therefore to use a PNECplant-air of 0.1 µg/m3 for
DBP in the revised
risk assessment. "
For the complete Article go to:
http://www.greenfacts.org/en/dbp-dib...nvironment.htm
Anybody with more info, please chime in. If you know of acceptable encapsulates for DBP containing plastics, please chime in!
Unity