Calling for a concrete action plan on EDCs

The following blog was submitted by Ni Zhu, a graduate student in CEE, as part of the requirements for GRAD 5414 Water for Health Seminar Interdisciplinary Seminar. This course examines emerging interdisciplinary issues related to the chemistry, microbiology, engineering and health aspects of drinking water.

It has been 53 years since Rachel Carson brought the alarming problem of misuse of synthetic chemicals to people’s attention in her book Silent Spring. The book has played an instrumental role in urging for more active public engagement and guided efforts toward environmental protection and conservation, which has also led to the creation of the U.S. Environmental Protection Agency. The book was specifically focusing on detrimental effects of artificial pesticides, but this group of exogenous compounds has grown to encompass a much wider category of contaminants, more commonly known as endocrine disrupting chemicals (EDC). In the most updated EPA Contaminate Candidate List 4 (draft), it has included 100 chemicals to be evaluated for their occurrence and potential public health risks. The list covers a wide range of chemicals, including commonly used industrial raw materials, pesticides, biological toxins, artificial hormones, disinfection byproducts and pharmaceutical and personal cares products etc. However, a point to note here is that despite the well-justified concerns associated with these contaminants, they are currently not subjected to any regulatory enforcement.

One major hindrance that is limiting development of enforceable regulation on EDCs is the knowledge gap between the basic research findings on the detection and risk characterization of EDCs with quantifiable public health impacts. The unique difficulties associated with detecting and monitoring EDCs in the environment include:

• Only traces amount is needed for some EDCs to trigger a biological effect, especially hormones, pharmaceuticals, drugs, at concentrations below the detection limit of the equipment (Birnbaum, 2010).
• EDC encompasses a wide array of compounds and treatment efficiency varies greatly among different treatment processes. Degradation performance of EDCs by conventional wastewater treatment processes varies from 23% to 100% (Auriol et al., 2006).
• Multiple routes of interaction and exposure exist between individuals and various EDCs. The effects of simultaneous exposure to multiple EDCs could result in very different combined outcome, depending on if the chemical reacts addictively, synergistically or antagonistically (Kortenkamp, 2008).

Given the aforementioned knowledge gaps and inadequate data of the effects of EDCs on humans, a prudent way is to follow the precautionary principle. While the regulatory authorities are conducting research and collecting data to better detect and characterize EDCs, other stakeholders, such as the water industry, the major industries contributing to the release of EDCs to the environment, relevant public sectors, interested NGOs, need to take a step up towards pushing for greater understanding and public awareness of this issue. A more well-informed public will, in turn, advocate for more concerted efforts towards establishing and implementing clear guidelines on the acceptable levels of EDCs in the environment.

References:

Auriol, M., Filali-Meknassi, Y., Tyagi, R. D., Adams, C. D. & Surampalli, R. Y. Endocrine disrupting compounds removal from wastewater, a new challenge. Process Biochem. 41, 525–539 (2006).

Birnhaum, L., Endocrine disrupting chemicals in drinking water: risks to human health and the environment. Committee on Energy and Commerce, United States House of Representatives. (2010).

Kortenkamp, A., Low does mixture effects of endocrine disrupters: implications for risk assessment and epidemiology. Int J Androl 31:233-240. (2008)