Bt Brinjal The scope and adequacy of the GEAC environmental risk assessment

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34 Bt Brinjal: The GEAC environmental risk assessmentThe data are insufficient forevaluating whether Bt brinjal disruptsnatural biological control (farmer’sfriends), and thereby causes a secondarypest outbreak. The natural enemies werenot very abundant in the study, and thedata do not distinguish among species.When a species is rare, it is very difficultto determine the effect of an experimentaltreatment. Differentiation of the datato identify species, rather than speciesgroups, is necessary to draw conclusionsabout the disruption of biological control.BOX 7The Root RhizosphereThe influence of a living plant on the soil is related to the proximity of the soil to the livingroot. Living plants interact with the soil through their roots. Plant roots are leaky and plantcompounds leave the root into the surrounding soil. Soil organisms, including bacteria andfungi can seek out the resources leaked from roots and establish complex ecological communitiesnear the root. Because of the importance of living roots in the soil, the “rootrhizosphere” is defined as the couple of centimetres from the main plant roots.Bt brinjal, like other GM crops, is expected to have its greatest influence on the soil in theroot rhizosphere, if it has any influence at all. Similar to many plants, brinjal has a complexroot structure that changes daily (see Brinjal Root, figure below,http://www.soilandhealth.org/01aglibrary/010137veg.roots/010137ch27.html ). Brinjal has amail tap root, and does not have a fibrous root structure. Therefore to evaluate the effect ofBt brinjal on soils, the rhizosphere soil should be sampled.Finding 16. The soil studies werenot designed for evaluating effects onsoil health, brinjal productivity, or theproductivity of other crops grown bybrinjal farmers, and therefore, is nothelpful for evaluating environmentalsafety.The soil experiments are supposedThe most common way to collect rhizosphere soil is to dig up the root system, shake off theto address potential adverse effect (B) loose soil, and collect soil that is still adhering to the root mass (Icoz et al., 2008, see figure on“reduction in soil quality or health,right below). The method used in the experiment was to take “root zone” soil from as faraway as 20 cm from the plant stem (figure on right below; blue area has a radius of 20cm).adversely affecting crop production in This method would include a substantial amount of non-rhizosphere soil in the samples,either the short or long term.” Thewhich would dilute any effects that could have occurred in the rhizosphere. The samplingmethod makes it very difficult to detect any effects of Bt brinjal.experiments in the Dossier (volume 5)and the Supplemental Materials focusRootzoneon the five response variables: totalareaculturable bacteria, total culturable12fungi, total nematodes, total collembola,Plant3and total earthworms. There are45three significant sources of uncertaintyNon-rootzone areaassociated with these studies that makethe studies incapable of evaluatingenvironmental safety.First, the response variables donot relate to soil quality associated with brinjal production in India, or if they relate, it is only through tenuous indirectconnections. The responses have been used in Bt maize in the temperate zone, but even in this circumstance, they have been ofsupplementary value, to other more critical measures. EC-II has not provided any justification for how these measures relate toIndian soils under brinjal. For example, if total cultural bacteria were higher in Bt brinjal, would this mean that soil quality isbetter or worse? Culturable bacteria represent only a few percent of all soil species, so environmental meaning of this measureis dubious. If the response does not allow an inference regarding soil quality or health or crop production, then the responsecannot be interpreted in the context of environmental risk.A better study design would include direct associations between measured responses and environmental effects. If, forexample, nutrient or micronutrient depletion were one of the indicators of long term soil health for brinjal or vegetable
Environmental Risk Assessment 35production in India, then the level ofBOX 8appropriately selected nutrients and/ ormicronutrients should be examined. IfScientific Validitybuild-up of refractory soil organic matter(SOM) were an indicator of long-term soil There are numerous factors that contribute to the scientific validity of ahealth (it improves water holding capacity scientific study, but two are absolutely essential: replication and reportingand improves soil aggregate distribution sufficient statistics.and soil structure), then the production Replication is absolutely essential for any scientific study, and replicationand degradation of refractory SOM should is equally important for studies supporting environmental risk assessment.be examined. If the use of a Bt crop were An unreplicated study is merely an anecdote, and should not be permitted asto create a soil “toxicity” or suppressiveness evidence in an environmental risk assessment. Replication is essential becauseto subsequent crops, then this should be it gives the risk assessor a certain confidence that the reported results are notdirectly evaluated, along with feasible ways merely a one-off chance happenstance. The greater is the replication, the morethat suppressiveness could build up in the confidence can be placed in the results.soil.That two studies on soil biology even appear as Supplementary Materials toSecond, the collection of the soil EC-II indicates a standard well beneath minimal scientific norms. Such studiessamples may be faulty (Box 7). Byshould not have been accepted.sampling soil from as far away as 20cm A second critical and often poorly understood factor essential to scientificfrom the main brinjal stem, actual effects validity is the reporting of sufficient statistics. This is a minimal standardof Bt brinjal could have been diluted to for reporting scientific results and has been violated numerous times in thethe background levels, resulting in the Dossier and Supplemental Materials. In short, all studies should report allinsignificant results. Thus dilution of treatment means, some measure of variance around the mean, and the samplerhizosphere soil is a possible alternative size contributing to the mean. None of the soil studies reported a measure ofexplanation for the reported no observed variance for any of the response variables. Even more astounding, treatmenteffects, and the true meaning of the results means are not reported for some of the response variables. These oversightsis not known.also occur in most of the other studies. Without this minimal information,Third, it is essential to know species it is impossible to evaluate the quality of the data and the soundness of theidentification as much as possible,conclusions.especially for the collembola andearthworms. This is because community responses of groups of species may mask important species-specific responses.Some final points about the scientific validity of and reporting of data in the studies need to be made (Box 8). The resultsreported in the two reports on soil biology in the Supplementary Materials are based on unreplicated trials. Because of thelack of replication, these data should not be admitted as evidence in a risk assessment. That these two studies even appear asSupplementary Materials to EC-II indicates a standard well beneath minimal scientific norms. Replication is absolutely essentialfor any scientific study, and replication is equally important for studies supporting environmental risk assessment.Finding 17. The EC-II (page 41) statement “there is no accumulation of the [Bt] protein in the soil associated withproduction of Bt brinjal” was not supported by any scientific data.The statement (EC-II, page 41) cites results from Bt cotton, and EC-II provides no justification that the results from cottonare at all relevant for Bt brinjal. Results from Bt maize demonstrate that Cry toxins persist for up to three years in soils(Zwahlen and Andow 2005). EC-II could have used maize data and come to the opposite conclusion. Actually, neither cottonnor maize is a good model for understanding degradation and accumulation in brinjal. The relevant data would be for brinjalitself.In general, degradation depends on the initial concentration the Bt protein (Ccry1A toxin) and exposure to factors thatdegrade the toxin. These in turn will depend on the structure of the brinjal plant (e.g., stem diameter, leaf to stem ratio, etc), thetillage systems used after brinjal production, and the season of production of the brinjal. Thus, the three varieties of Bt brinjal
Page 1 and 2: Table of Contents 1Bt Brinjal Event
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Page 5 and 6: Summary and Conclusion 1Summary an
Page 7 and 8: Summary and Conclusion 3The EE-1 t
Page 9 and 10: Summary and Conclusion 5Event EE-1
Page 11 and 12: Summary and Conclusion 7Conclusion
Page 13 and 14: Context and Need 9standards for ER
Page 15 and 16: Context and Need 11and seek to incr
Page 17 and 18: Context and Need 13the reported yie
Page 19 and 20: Characterisation of Transgene 15Cha
Page 21 and 22: Characterisation of Transgene 17wor
Page 23 and 24: Characterisation of Transgene 19In
Page 25 and 26: Characterisation of Transgene 21Sci
Page 27 and 28: Environmental Risk Assessment 23Gen
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Bt Brinjal The scope and adequacy of the GEAC environmental risk assessment

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