Environmental Defense Fund: Finding the Ways That Work

DuPont

Feedback from PETA

People for the Ethical Treatment of Animals

Posted on: March 26, 2007

Dear Sirs,

As the largest animal rights organization in the world, with 1.6 million members who care about the suffering of animals in laboratory testing, PETA has serious concerns with the draft DuPont–Environmental Defense (ED) Nano Risk Framework. Firstly, it is unclear where and how this Framework fits into the regulatory scheme of nanotechnology testing, how public comments are being solicited and how they will be addressed, whether they will be made public, why EPA is funding ED’s work on this project, EPA’s involvement in this project, and the overall transparency of this apparently government-funded project.

Secondly, we are particularly troubled by the lack of reference to validated non-animal methods for the recommended toxicity testing and the absence of a tiered approach that has a basis in in vitro methods.

Designing a framework by which nanomaterials can be effectively tested and deemed safe for humans and the environment is a critical, yet difficult task. It is for this reason that regulatory agencies have not yet put in place a framework of their own. Although there are many aspects of a reasonable plan within the Framework, a lack of specificity and reference to the most modern methods applicable for each safety-testing category cause this framework to be only marginally useful.

As PETA’s Nanotechnology Policy Advisor, a member of the U.S. TAG 229, Nanotechnologies, and an invited presenter at multiple international conferences on nanotoxicology, I would like to address the testing categories of the Framework and make suggestions that will make it more useful and clear. There is great responsibility that comes with designing a framework intended for use by industry stakeholders and we hope that DuPont and Environmental Defense (ED) will consider the recommended changes in order to make it a more relevant guideline. The “Output Worksheet” provided as an appendix of the Framework is designed as a checklist of toxicity testing data to be collected by those who are characterizing nanomaterials. The 15-page worksheet is remiss in that it does not include the most modern, reliable methods accepted by the OECD and other relevant agencies for various toxicity testing categories. Although a great deal of thought may have been invested in choosing the categories of toxicity tests to be conducted, there seems to have been little effort to guide researchers to the best tests for each category. We strongly encourage DuPont and ED to add to their list of tests specific OECD-accepted tests that will provide human-relevant data while requiring the fewest number of animal experiments.

Few corporations are poised in such a position as to provide great influence on a burgeoning industry. Dupont’s position also comes with great responsibility. As DuPont is aware, in vitro/in silico-based human relevant data are predictive of human health and safety and are far less costly than animal experimentation. As DuPont’s animal welfare policy states, “DuPont shares society's desire to increase the use of scientifically validated alternative methods that reduce, refine or replace the use of animal models in research. We are strong proponents of "intelligent" testing strategies, which minimize the use of animal testing by using a tiered approach to data collection.” We remain hopeful that DuPont and ED will rethink its approach and we look forward to continued discussion on this important matter.

Proposed Framework Reorganization:

We urge DuPont and Environmental Defense to add additional tiers in the proposed framework and to specify the appropriate methods for each proposed tier of testing. In addition, the framework should specify the manner in which a researcher should navigate from Tier I, to Tier II, and finally to Tier III within the proposed testing strategy.

Instead of immediately resorting to in vivo testing data, we suggest that the primary and secondary tiers of tests in the Framework focus on the wealth of in vitro tests available and include those listed in our proposed first and second tiers. Here, we propose that Tier I should address general toxicity parameters. Tier II allows the accumulation of more specific toxicity data without experimenting on animals. This testing paradigm is both efficient and cost effective. Only if toxicity testing within the first two tiers shows that the nanomaterial of interest does not show a propensity for toxicity does additional testing for regulatory approval need to be done. Because DuPont has, to date, been an advocate for tiered testing that avoids in vivo testing, failure to do so in this context is surprising.

Proposed Tier I

Health Hazard Data:
  • Skin sensitization/irritation: Please specify that OECD Test Guideline 429 (LLNA) is a partial replacement for the guinea pig tests often used to test skin sensitization and that EPISKIN™-SIT is a complete ECVAM-validated replacement for in vivo skin irritation tests for skin irritation.
  • Skin penetration: The In Vitro Skin Absorption Test is a full replacement for the in vivo skin penetration test under OECD TG 428. Please make note of this method in the Framework.
  • Genotoxicity: Although, the Framework makes mention of “gene mutation in prokaryotic cells” and “chromosomal aberration” assays, we suggest specifying the Ames test for bacterial mutation (OECD TG 471), testing for mutagenicity by in vitro chromosomal aberration (OECD TG 473), Unscheduled DNA synthesis (OECD 482), Sister Chromatid Exchange (OECD 479) each of which can be a partial or full replacement for in vivo methods. Negative results for these assays preclude the use of additional in vivo test confirmation.
Environmental Hazard Data:

It appears as though the Framework has neglected to include tests on soil bacteria to measure toxic effects due to nanomaterials that could change the balance of an ecosystem. In addition to their effect on bacterial species, the effect of nanomaterials on both aquatic and terrestrial plants is of concern and we are pleased to see that studies involving plants have been included in the framework. Toxicity to invertebrates such as the water flea, Daphnia, is also important. Much can be learned about a given nanomaterial’s impact on the environment by testing for toxic effects on base-level organisms.

Proposed Tier II:

Next steps for “additional” health hazard data should include tests which have been accepted for use by OECD, ECVAM, and or ICCVAM that allow nanomaterials to be assessed for their toxic effects.

  • Skin Corrosivity: Using CORROSITEX (OECD TG 435) as a full replacement for the in vivo skin corrosion test for acids, bases, and acid derivatives. EpiDerm and EPISKIN each serve as full replacements for the in vivo skin corrosion test (OECD TG 431).
  • Phototoxicity: The 3T3 Neutral Red Uptake Test is considered a replacement for the in vivo photoirritation tests (OECD TG 432) and has gained FDA preference.
  • Ocular Corneal Opacity-Permeability Test: ICCVAM and EU approved for use as a positive screen for ocular corrosivity and severe irritation and is acceptable for use based on the sequential testing strategy supplement to OECD TG 405.
  • Acute Neutropenia: In order to predict chemical-induced neutropenia, the CFUMG assay has been validated for use by ECVAM and endorsed by ESAC.
  • Pyrogenicity: The PBMC/IL-6, WB/IL-1, CryoWB/IL-1, WB/IL-6, and MM6/IL- 6 tests are now under ICCVAM peer review and should be considered as replacements for the rabbit and LAL tests.
  • Embryotoxicity: Partial replacements for the in vivo developmental toxicity test exist and include tests such as: Embryonic Stem Cell Test, Rat Limb Bud Test, and Micromass Test. Each of these tests is ECVAM validated and should be employed prior to moving to animal experiments that may be required by regulatory agencies.
Final Tier of Toxicity Testing:

At this point, regulatory agencies may require animal experimentation prior to giving final approval for product use; however, researchers should maintain a conservative approach towards animal-based toxicity testing and resist animal experiments until it is clear that Tier 1 and Tier 2 non-animal methods indicate that the nanomaterial may be incorporated into consumer goods and therefore must undergo animal testing per regulatory requirements. Employing the most high-throughput, human-relevant testing paradigm will allow the field of nanotechnology to progress without the pitfalls of unpredictive animal experimentation.

Good Stewardship:

Again, we reiterate the confusion concerning the role DuPont and Environmental Defense are playing in this matter but, regardless, they have a responsibility to produce a worthwhile toxicity testing framework rather than referencing every conceivable toxicity test and neglecting to specify where validated non-animal methods are the preferred tests to be performed.

We look forward to an explanation regarding this Framework’s role and seeing a newly drafted document that seeks to help collect the most meaningful data as well as encouraging the use of the most cutting-edge, high-throughput testing methods available at this time. We trust that DuPont and Environmental Defense will take this responsibility seriously and will want to make the most positive impact on nanomaterials safety while reducing animal experimentation to the greatest extent possible.

Sincerely,

Samantha Dozier, Ph.D.
Nanotechnology Policy Advisor
Regulatory Testing Division