Water & Wastewater Treatment Magazine
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www.wwtonline.co.uk | WWT | NOVEMbEr 2016 | 35 In the know Research Notes: trace contaminants The wastewater headache a er taking an aspirin Trace contaminants, including chemicals from pharmaceutical and household products that are part of our daily lives, are a growing area of concern in the water environment. Cranfield University's Dr Pablo Campo- Moreno summarises the latest research on the issue in terms of water quality. Owing to significant improvements in analytical sensibility and accuracy, the driving force behind this intensive search for trace contaminants has been advances in instrumentation. Consequently, more powerful equipment has facilitated the detection of contaminants at the part-per-trillion or part-per-billion concentration levels in surface and ground waters, something otherwise unattainable by means of conventional techniques. In addition to effluents from chemical manufacturing, food industry and agricultural activities, the occurrence of trace contaminants in water is, for most of the part, due to domestic streams. In our daily living we utilise personal care products, pharmaceuticals and household cleaners, among others substances, that contain these chemicals as ingredients and active components. Thus common practices such as body hygiene, doing the laundry or taking a tablet to alleviate a headache contribute organic compounds, in tiny amounts, to waterways. For instance, drugs enter sewage systems a•er being excreted by patients, via human waste, or because in some places the preferred method of disposal for old medicaments is flushing them down the toilet; hence more than 200 pharmaceuticals have been found in river waters worldwide. While traditional wastewater treatment plants - mainly biological processes - are the main point of convergence for trace contaminants, these facilities were designed for the removal of bulk organic matter as well as nutrients (nitrogen and phosphorus), without further consideration for the elimination of trace contaminants. In fact, the amounts in which the trace contaminants exist in wastewater are insufficient for supporting microbial growth. As a result, freshwater bodies such as rivers, lakes and reservoirs closer to industrial and population sources are the environmental compartments receiving the greatest percentage of trace contaminants. The presence of these chemicals has escalated concerns as their potential impact on the biota and human health is not well understood. In general, trace contaminants are o•en associated with harmful effects such as acute and chronic toxicity, endocrine disruption, antibiotic resistance as well as bioaccumulation. G ot a headache? Most people wouldn't think twice about taking an aspirin to alleviate the pain, but they might when they realise the cumulative effect this (and other perceived benign activities) are having on our environment, wildlife, and ourselves. From chronic toxicity to antibiotic resistance, trace contaminants from both the unusual (and usual) suspects are a cause for real concern, yet amazingly there are currently no regulatory standards in terms of water quality. Addressing this situation, the EU Water Framework Directive aims to improve levels in water quality. In Pharmaceuticals find their way into wastewater in small quantities Dr Pablo CamPo-moreno LeCtUrer in APPLieD Chemistry CrAnfieLD University response to this, a collaborative effort involving Cranfield University and other leading institutions resulted in the Chemical Investigation Programme – a first step in combating the problem of unrecognised or recorded trace contaminants. What are trace contaminants? Just within the last decade, scientific studies reporting the presence of trace contaminants in aquatic environments can be counted by thousands. The expression 'trace contaminant' groups an array of compounds, mainly natural and synthetic organic chemicals, to which no regulatory standards apply