Low levels of artificial sweeteners present in the aquifer, but what’s safe?

By Mike Ekberg, MCD manager for water resources monitoring and analysis MCD staff recently found artificial sweeteners in five of 12 groundwater samples. The samples were collected from monitoring wells installed in the buried valley aquifer. This is further proof that many of the chemicals we flush down a toilet, rinse down a sink, or apply to our lawns and gardens ultimately end up in our rivers, streams, and aquifers. It should be noted that none of the wells sampled in the study are used for drinking water. MCD uses its monitoring wells in the buried valley aquifer to act as a network of sentinels. Samples from the wells provide information on human impacts as well as natural changes in the quality of water over time. MCD found artificial sweeteners in several groundwater samples (in monitoring wells, not drinking water wells), providing further proof that what we flush down the toilet and rinse down the sink makes its way to our rivers, streams and aquifers. Artificial sweeteners in groundwater is a concern for two reasons: First, their presence is an indication that human sewage is flowing into the aquifer. Human sewage contains low levels of many contaminants that pass through the sewage treatment process and enter into natural waters. Second, artificial sweeteners are considered to be potential endocrine disruptors because they may interfere with the body’s endocrine system and harm people and animals. The endocrine system is a chemical messaging system within the human body that regulates organ function. Fortunately, the artificial sweeteners were present in the groundwater at very low concentrations – parts per trillion.

These "endocrine disruptors." as they are known, are present in many products we use every day, including plastic bottles, detergents, flame retardants, cosmetics, and pesticides. Among the other chemicals MCD found in the samples were:

• Bisphenol A (BPA), a compound found in plastics.
• DEET, an active ingredient in insect repellant.
• The herbicides atrazine, metolachlor, simazine, and sulfometuron methyl.
• Meclofenamic acid, a drug used for joint and muscular pain and arthritis.
• Propylparaben, an ingredient in many cosmetics.

BPA is becoming a big concern because human exposure to the compound is widespread. Some animal studies report effects on fetuses and newborns exposed to BPA. None of the chemicals found exceeded any human health-based standards. The jury is still out, however, on what the standards should be for some of these chemicals. It’s possible that new standards will be set once we better understand how these chemicals affect the human body. If we want clean, safe water, we may need to support investments in advanced water treatment technologies to remove potentially harmful compounds from water.  

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