Review Article on Water Analysis: Emerging Contaminants and Current Issues

2003 Research Abstracts - Table of Contents

National Exposure Research Laboratory - FY03 Research Abstract

Scientific Problem and Policy Issues

This invited review for the journal Analytical Chemistry (June 2003) covers developments from 2001-2002 in water analysis. The author (Dr. Richardson) this year chose to narrow the focus of the review to new, emerging contaminants and environmental issues that are driving most of the current research. Numerous abstracts from the scientific literature were consulted before choosing the most-representative ones to include for this review. In addition to covering general reviews involving water analysis and new regulations and regulatory methods that relate to water analysis, Dr. Richardson also discusses new research on drinking water disinfection by-products (DBPs); pharmaceuticals, hormones, and endocrine disrupting compounds; chiral contaminants; methyl-tert-butyl ether (MTBE); algal toxins; organotins; perchlorate; arsenic; natural organic matter; and microorganisms.

Research Approach

DBPs: In addition to new regulations involving DBPs (e.g., the Stage 1 and Stage 2 Disinfectants/DBP Rule), there are new, emerging issues with DBPs. Human exposure research has revealed that ingestion is not the only important route of exposure–inhalation from showering and dermal adsorption (from bathing and other activities) can provide similar or higher exposures to certain DBPs. In addition, DBPs beyond those that are currently regulated are becoming important. Specific DBPs that are of current interest include bromonitromethanes, iodo-trihalomethanes, brominated forms of MX (MX is 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone), and nitrosodimethylamine (NDMA). New research on DBPs is detailed in this review, including new human exposure research, occurrence data and analytical methods for toxicologically important DBPs, fate studies on DBPs, formation mechanisms for NDMA, and the identification of new DBPs.

Pharmaceuticals, hormones, and endocrine disrupting compounds: These compounds are becoming major issues in environmental chemistry due to their presence in environmental waters (following incomplete removal in wastewater treatment or point-source contamination) and concern about possible estrogenic and other effects, both to wildlife and humans. Pharmaceuticals that have been detected directly or as their metabolites include antibiotics, analgesics and anti-inflammatory drugs, lipid regulators, beta-blockers, antiepileptic drugs, oral contraceptives, and steroids and hormones. Although their environmental levels are generally very low (low ng/L), these levels may be sufficient to induce estrogenic responses and cause reproductive and developmental effects in wildlife. New research on pharmaceuticals, hormones, and endocrine disrupting compounds is detailed in this review, including occurrence and fate data on these compounds in drinking water, surface waters, and wastewaters.

Chiral contaminants: It was not until recent developments allowed the separation and low-level of detection of chiral isomers that their environmental behavior could be studied. However, early research is showing that the behavior of chiral compounds is not straightforward–it is not always possible to predict the enantiospecific transformation. New research on the occurrence and fate of chiral compounds (including chiral pesticides), as well as new analytical methods for their measurement, is detailed in this review.

Methyl-tert-butyl ether (MTBE): MTBE contamination is a concern, due to its introduction into groundwater and surface waters through leaking underground gasoline storage tanks and discharges of fuel from boats and other watercraft. New occurrence information, analytical methods for measuring MTBE, and technologies for removing it are including in this review.

Algal toxins: Algal toxins have been responsible for increased incidences of shellfish poisoning, large fish kills, deaths of livestock and wildlife, and illness and death in humans. Methods for measuring different algal toxins are presented, as well as occurrence information, including new recent reports of the presence of algal toxins in finished drinking water.

Organotins: Organotins are widely used in antifouling paints for ships and have been measured widely in coastal waters and sediment. A recent discovery that dibutyltin leaches from polyvinylchloride (PVC) pipe at 1 g/L levels has created a new concern for drinking water. New analytical methods developed for measuring organotins (including a new EPA method) are presented, as well as new occurrence information on organotins in water.

Perchlorate: Perchlorate, a rocket fuel component, has recently become an important environmental issue since its discovery in a number of water supplies in the western United States. The development of sensitive analytical techniques has revealed perchlorate in surface waters and ground waters primarily in the southwestern United States. New methods for measuring perchlorate, as well as occurrence information and methods for removing perchlorate are presented in this review.

Arsenic: Recent issues including the determination of individual species of arsenic, rather than total arsenic, and new analytical methods developed for measuring these species at low levels in water are presented.

Natural Organic Matter: Natural organic matter (NOM) is a complex mixture of substances, including humic acids, and impacts such processes as the sorption or transformation/degradation of environmental pollutants, provides sources and sinks for carbon, serves as a carbon and energy source for biota, and controls levels of dissolved oxygen, nitrogen, phosphorus, sulfur, trace metals, and acidity. Also, importantly, NOM serves as the precursor material for the formation of drinking water DBPs. New information provided by electrospray ionization mass spectrometry is showing much lower molecular weights for NOM (e.g., 300 to 1200 for humic acid) than earlier gel permeation work (e.g., 100 to 100,000). These new results are presented in this review, along with a discussion of the controversy these results have created.

Microorganisms: New mass spectrometry methods (including matrix-assisted laser desorption ionization mass spectrometry and electrospray ionization mass spectrometry) are enabling the rapid identification of bacteria and other microorganisms through the identification of marker proteins. New mass spectrometry methods, as well as new biological and biochemical methods are presented in this review.

Results and Implications

The emerging contaminants discussed in this review are environmentally important; some are already listed on EPA's Contaminant Candidate List (CCL); others are the subject of intense research and may be considered for regulation in the future.

Research Collaboration and Publications

Future Research

For some of the areas (e.g., pharmaceuticals), research needs and future directions are discussed. The author is invited by Analytical Chemistry to write this review every two years. A follow-up review on the next two years of research is scheduled for 2005.

Contacts for Additional Information

Questions and inquiries can be directed to:
Susan D. Richardson, Ph. D.
US EPA
960 College Station Rd.
Athens, GA 30605-2700

Phone: 706/355-8304
E-mail: richardson.susan@epa.gov

2003 Research Abstracts - Table of Contents

Exposure Research Home

Atmospheric Modeling | Ecological Exposure Research | Ecosystems Research | Environmental Sciences
Human Exposure & Atmospheric Sciences | Microbiological & Chemical Exposure Assessment Research

EPA Home | Privacy and Security Notice | Contact Us