In aerobic aquatic environments, the half life is 15 days, while in anaerobic aquatic environments, 2,4-D was moderately persistent to persistent (half life of = 41 to 333 days). 2,4-D has been detected in streams and shallow groundwater at low concentrations, in both rural and urban areas. Breakdown is pH dependent. Some ester forms are highly toxic to fish and other aquatic life. "The ester forms of 2,4-D can be highly toxic to fish and other aquatic life. 2,4-D generally has moderate toxicity to birds and mammals, is slightly toxic to fish and aquatic invertebrates, and is practically nontoxic to honeybees" per EPA. A number of 2,4-D-degrading bacteria have been isolated and characterized from a variety of environmental habitats. Metabolic pathways for the compound’s degradation have been available for many years, and genes encoding 2,4-D catabolism have been identified for several organisms. As a result of the extensive metadata on environmental behavior, physiology, and genetics, 2,4-D was the first herbicide for which the bacteria actively responsible for "in situ "degradation were demonstrated. This was accomplished using the technique of DNA-based stable isotope probing, which enables a microbial function (activity), such as degrading a chemical, to be linked with the organism’s identity without the need to culture the organism involved. Maximum residue limits were first set in the EU in 2002 and re-evaluated in 2011 by the European Food Safety Authority, which concluded that the codex maximum residue limits were "not expected to be of concern for European consumers". The total chronic exposure represented less than 10% of the acceptable daily intake (ADI). Concern over 2,4-D is such that it is currently not approved for use on lawns and gardens in Denmark, Norway, Kuwait, and the Canadian provinces of Québec and Ontario. 2,4-D use is severely restricted in the country of Belize. In 2008, Dow AgroScience, LLC, sued the Canadian government for allowing Quebec to ban 2,4-D, but settled in 2011. In 2005, the US EPA approved the continued use of 2,4-D. On July 10, 2013, the Pest Management Regulatory Agency in Canada updated the re-evaluation notice of 2,4-D, stating that the 2,4-D registrants had provided it with required data and deemed them acceptable. On April 18, 2012, EPA denied the petition filed November 6, 2008, by the Natural Resources Defense Council to revoke all tolerances and to cancel all registrations of 2,4-D. EPA stated that recent new study and EPA’s comprehensive review confirmed EPA’s previous finding that the 2,4-D tolerances are safe at anticipated exposure.