{"id":782,"date":"2010-06-30T15:28:30","date_gmt":"2010-06-30T20:28:30","guid":{"rendered":"http:\/\/blogs.edf.org\/nanotechnology\/?p=782"},"modified":"2024-02-12T11:01:01","modified_gmt":"2024-02-12T16:01:01","slug":"hurry-up-and-wait-not-much-new-revealed-by-epas-initial-round-of-dispersant-toxicity-testing","status":"publish","type":"post","link":"https:\/\/blogs.edf.org\/health\/2010\/06\/30\/hurry-up-and-wait-not-much-new-revealed-by-epas-initial-round-of-dispersant-toxicity-testing\/","title":{"rendered":"Hurry up and wait: Not much new revealed by EPA&#8217;s initial round of dispersant toxicity testing"},"content":{"rendered":"<p><em>Richard Denison, Ph.D.<\/em><em>, is a Senior Scientist.<\/em><\/p>\n<p>EPA held a press call today to discuss the <a href=\"http:\/\/www.epa.gov\/bpspill\/dispersants-testing.html\" target=\"_blank\" rel=\"noopener\">initial results of its own testing<\/a> of oil spill dispersants.\u00a0 The testing by EPA was initiated after <a href=\"http:\/\/www.epa.gov\/bpspill\/dispersants\/5-21bp-response.pdf\" target=\"_blank\" rel=\"noopener\">BP resisted complying<\/a> with an <a href=\"http:\/\/www.epa.gov\/bpspill\/dispersants\/directive-addendum2.pdf\" target=\"_blank\" rel=\"noopener\">EPA-Coast Guard Directive issued May 20<\/a> that directed the company to identify and switch to dispersants that are less toxic and more effective than the two Corexit\u00ae dispersants on which BP has exclusively relied to mitigate the effects of the oil disaster unfolding at Deepwater Horizon.\u00a0 In expressing disappointment with BP\u2019s response to the Directive, <a href=\"http:\/\/www.epa.gov\/bpspill\/dispersants\/Rainey-letter-052610.pdf\" target=\"_blank\" rel=\"noopener\">EPA indicated it would initiate its own toxicity and effectiveness testing<\/a> of Corexit and other dispersants.\u00a0 Today\u2019s call reported on round 1 of that testing.<\/p>\n<p>First let me say I applaud EPA for taking on the unglamorous task of conducting further testing and seeking to answer questions that would have been nice to have had answers to well before this mess developed.\u00a0 Second, I understand that testing takes time, that this is only round one and EPA says more is coming, so that at least partially compensates for the distinctly anticlimactic feeling I had listening in on today\u2019s call.<\/p>\n<p>So, what did we learn today?\u00a0 Not too much new.<!--more--><\/p>\n<p>The initial round of testing was conducted on Corexit 9500 and seven other dispersants listed on the National Contingency Plan (NCP) Product Schedule.\u00a0 Here are my initial takeaways:<\/p>\n<ul>\n<li>The testing was done on the dispersants <strong><em>by themselves \u2013<\/em> <em>not in combination with oil<\/em><\/strong>.\u00a0 <a href=\"http:\/\/blogs.edf.org\/nanotechnology\/2010\/06\/14\/epa-data-show-dispersants-plus-oil-are-more-toxic-than-either-alone\/\" target=\"_blank\" rel=\"noopener\">I posted earlier<\/a> that acute toxicity increased as one progressed from dispersant by itself, to oil by itself, to the mixture of oil and dispersant.\u00a0 We\u2019ll have to wait longer for EPA to release data that will shed further light on whether that conclusion holds or not.<\/li>\n<li>What is most remarkable about the data EPA released today is<em> <strong>how similar they are to the industry-supplied data on the dispersants by themselves that were previously made available on EPA\u2019s website<\/strong>.<\/em> \u00a0With only a few exceptions, the new toxicity values changed by a factor of 2 or 3.<\/li>\n<li>The exceptions that involved slightly larger changes are:\n<ul>\n<li>JD-2000 appears to be 9-fold less acutely toxic to shrimp and at least 14-fold less toxic to fish than indicated by the previous data.<\/li>\n<li>Sea Brat #4 is about 5-fold less toxic to shrimp.<\/li>\n<li>Corexit 9500 is about 5-fold less toxic to fish, while Corexit 9500\u2019s toxicity to shrimp is essentially unchanged.<\/li>\n<\/ul>\n<\/li>\n<li>The before-and-after toxicity levels changed on average by a factor of 2.8 for shrimp and a factor of 3.1 for shrimp.\u00a0 Excluding JD-2000, the changes averaged only 2.0 for shrimp and 1.6 for fish.<\/li>\n<\/ul>\n<p>On this point, <a href=\"http:\/\/www.epa.gov\/bpspill\/reports\/ComparativeToxTest.Final.6.30.10.pdf\" target=\"_blank\" rel=\"noopener\">EPA\u2019s data report<\/a> concludes:\u00a0 \u201cGiven the expected range of inter-laboratory variability, the results of the present study were consistent with test results reported in the NCP Product Schedule, with the exception of two dispersants for each test species which yielded higher LC50s (i.e., lower toxicity) than reported in the NCP.\u201d<\/p>\n<p>The new data for Corexit 9500 by itself leave unchanged its classification by EPA as \u201cslightly toxic\u201d to shrimp, and downgrade its classification from \u201cslightly toxic\u201d to \u201cpractically non-toxic\u201d to fish.<\/p>\n<p>No new testing was done on Corexit 9527, which was used initially in the response to the spill.<\/p>\n<p>So, for the most part the new data largely confirm the previous data, while suggesting that one dispersant (JD-2000) is a fair bit less acutely toxic to fish and shrimp than its manufacturer\u2019s data indicated, and that Corexit 9500 is a bit less acutely toxic to fish, and about as toxic to shrimp as indicated by the earlier data.<\/p>\n<p>All of the <a href=\"http:\/\/blogs.edf.org\/nanotechnology\/2010\/05\/24\/oil-spill-dispersants-what-part-of-%e2%80%9ccontingency-plan%e2%80%9d-did-we-not-understand\/\" target=\"_blank\" rel=\"noopener\">bigger questions<\/a> remain, of course, including:<\/p>\n<ul>\n<li>Does dispersant use increase the acute toxicity of the oil?\u00a0 EPA describes its next round of testing as aimed at answering this question.<\/li>\n<li>What about sublethal and longer-term effects?<\/li>\n<li>What is the ultimate fate and impact of dispersed vs. undispersed oil?<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Richard Denison, Ph.D., is a Senior Scientist. EPA held a press call today to discuss the initial results of its own testing of oil spill dispersants.\u00a0 The testing by EPA was initiated after BP resisted complying with an EPA-Coast Guard Directive issued May 20 that directed the company to identify and switch to dispersants that &#8230;<\/p>\n","protected":false},"author":100,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[75,5009],"tags":[1061,39171,39204],"coauthors":[],"class_list":["post-782","post","type-post","status-publish","format-standard","hentry","category-environment","category-health-science","tag-bp-oil-disaster","tag-exposure-vs-hazard","tag-oil-dispersant"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/782","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/users\/100"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/comments?post=782"}],"version-history":[{"count":1,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/782\/revisions"}],"predecessor-version":[{"id":12588,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/posts\/782\/revisions\/12588"}],"wp:attachment":[{"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/media?parent=782"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/categories?post=782"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/tags?post=782"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/blogs.edf.org\/health\/wp-json\/wp\/v2\/coauthors?post=782"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}