Irrigating crops with recycled water can result in vegetables laced with small amounts of drugs and personal care chemicals, but researchers disagree on whether the contaminated produce is likely to harm people.
Global water shortage is placing an unprecedented pressure on water supplies. Treated wastewater is a valuable water resource, but its reuse for agricultural irrigation faces a roadblock: public concern over the accumulation of commonly-occurring pharmaceutical and personal care products (PPCPs) into human diet.
In a new study published in the journal Environmental Science & Technology, researchers irrigated eight vegetable crops with treated wastewater containing 19 drugs and chemicals that are commonly found in wastewater and difficult to filter out. Eight of the chemicals were detected in the edible portions of the mature crops, including:
• Meprobamate (a prescription tranquilizer)
• Primidone (an anticonvulsant medication)
• DEET (active ingredient in insect repellents)
• Carbamazepine (mood-stabilizer for epilepsy, bipolar disorder)
• Dilantin (anticonvulsant drug)
• Naproxen (nonsteroidal anti-inflammatory drug)
• Triclosan (antibacterial and anti fungal agent).
The total concentrations of PPCPs detected in edible plant tissues from the treated wastewater and fortified irrigation treatments were in the range of 0.01 3.87 and 0.15 7.3 ng/g (dry weight), respectively.
Annual exposure of PPCPs from the consumption of mature vegetables irrigated with the fortified water was estimated to be only 3.69 μg per capita. Results from the present study showed that the accumulation of PPCPs in vegetables irrigated with treated wastewater was likely limited under field conditions.
Source: Wu X, Conkle JL, Ernst F, Gan JJ. Treated Wastewater Irrigation: Uptake of Pharmaceutical and Personal Care Products by Common Vegetables under Field Conditions. Environ Sci Technol. 2014 Sep 11.