Researchers Complete Rebuttal of Inspector General Report on Biosolids

(July 30, 2020) – Members of the US Department of Agriculture’s Multistate Research Committee, known as W4170, recently completed a rebuttal of the November 2018 EPA Office of Inspector General (OIG) report on biosolids land application.

The OIG report, entitled “EPA unable to assess the impact of unregulated pollutants in land-applied biosolids on human health and the environment” was met with strong criticism from the water sector and EPA’s Office of Water for its alarmist tone and sweeping conclusions about risk, which were not supported by the body of scientific information currently available.

In its initial response to the OIG, EPA’s Office of Water (OW) characterized the report as lacking in science and context, as well as being alarmist and biased. EPA OW correctly pointed out that the mere presence of the pollutants mentioned in the OIG report does not indicate risk. 

The W4170 rebuttal, which began with an extensive review of the available science, agrees, concluding: “the OIG report did not consider the concentration of chemicals found in the biosolids” and that overall “sufficient data and research are available to conclude that current biosolids regulations are protective of human health and the environment.” Further, the W4170 rebuttal points out that the bulk of human exposure to these chemicals is from domestic use of consumer goods and that only trace amounts are found in biosolids. 

Several chemicals were identified in the W4170 report as requiring further study, including several persistent pharmaceuticals, and the researchers noted that “as with any regulation intended to protect public health and the environment, they must always by dynamic and evolve with updated science.” NACWA and its members have fully supported additional research on biosolids and through its aggressive advocacy have worked to support EPA’s biosolids program to do this work.

For additional information on this report, please contact Chris Hornback, NACWA’s Deputy Chief Executive Officer.