Occurrence and Persistence of Pesticides, Pharmaceutical Compounds, and other Organic Contaminants in a Conventional Drinking-Water Treatment Plant R.H.

Occurrence and Persistence of Pesticides, Pharmaceutical Compounds, and other

Organic Contaminants in a Conventional Drinking-Water Treatment Plant

R.H. Coupe, PhD and D.P. Bach, P.E.

Introduction• More than 100,000 synthetic chemicals are used in a variety of

domestic, industrial, and agricultural applications.

• Numerous studies have documented that many of these compounds, including pharmaceuticals, fragrances and flavorants, flame retardants and plasticizers, detergent metabolites, components of personal care products, and products of petroleum use and combustion are incompletely degraded or removed during waste water treatment and are persistent in the aquatic environment.

• It has also been shown that some of these compounds can survive conventional drinking water treatment and persist in finished potable water (Stackelberg and others, 2004; Coupe and Blomquist, 2004).

Introduction - continued

• Those communities that depend upon a surface water supply for their drinking water are vulnerable to up basin activities.

• These include:atmospheric deposition agriculturesilvilcultureindustryconstructionminingurban etc…

Ross Barnett Reservoir

• 33,000 acre impoundment created by damming the Pearl River in 1965.

• Created for drinking water supply and recreation.• Drinking water supply for the city of Jackson, MS.• There is an aquatic vegetation problem in the reservoir;

Waterhyacinth, alligatorweed, and hydrilla.

Pearl River Basin in Mississippi

Upper Pearl Basin

• Approximately 3,000 mi2 drainage area

• Land use is mostly forest (silvilculture) and some agriculture

• Some small urban areas with POTWs: Louisville, Kosciusko, Carthage, Forest, Philadelphia, etc…

Objectives

• The objectives of this work were (1) to determine, if pesticides, pharmaceuticals, and other organic compounds can be detected in the Ross Barnett reservoir and (2) if detected, were they also found in the finished water from the O.B. Curtis drinking water plant.

Scope

• Collect 3 sets of samples: 8/24, 8/30, & 9/5/2006during the low flow season this would maximize

the contribution from point sources, but minimize those from nonpoint sources.

• Each set consisted of 3 samples: one from the intake structure, one after sedimentation but before chlorination, and one from the finished water supply.

• Each water sample was analyzed for more than 200 compounds.

Scope -- continued• Samples were sent to the USGS National Water Quality

Laboratory in Denver Colorado for analysis.• Pesticides – Filtered Water, Solid Phase Extraction --

capillary-column gas chromatography/mass spectrometry with selected-ion monitoring or graphitized carbon-based solid-phase extraction and HPLC– High use, water soluble pesticides and pesticides metabolites.

• Waste-Water Indicator Method –Whole water, Liquid-Liquid Extraction and capillary-column GS/MS– Alkylphenol ethoxylate nonionic surfactants, food additives,

fragrances, antioxidants, flame retardants, plasticizers, industrial solvents, disinfectants, fecal sterols, and polycyclic aromatic hydrocarbons

O.B. Curtis Water Treatment Plant Process Schematic

Intake water Ross Barnett Reservoir

Dual 1 mm raw screens

Potassium Permanganate for clam & Mn control (as needed)

Dual Pre-oxidation Basins

NH4 for algae control (as needed)

Lime for pH control (as needed)

Dual Rapid Mix units

Chlorine to combine with NH4 for algae control (as needed)

Flocculators and Sedimentation Basins

ACH & anionic polymer to aid in coagulation

Lime, PAC (as needed)

Six dual media filters

Clean water

Fluoride, lime & chlorine for disinfection UV (not in operation during study)

Membrane ultrafiltration (not in operation)

Settled solids to Handling Facility Chlorine Dioxide for Mn control (as needed)

Backwash to Handling Facility

Results – Waste Water Indicators

Compound Date Intake (ug/L) Finished (ug/L)

Caffeine 8/24 0.0233 0.0132

Deet 8/30 0.0642 0.0619

Desulfnyl fipronil 8/24 0.0053 0.0050

A few compounds (Phenyl Cyanate, Camphor, and Cholesterol) were found in the source water, but not in finished water. With a couple of exceptions (above and below), there were few detections of waste water indicators in either the source or finished water.

Results – Herbicides (part 1)

Herbicide Date Intake (ug/L) Finished (ug/L)

Atrazine All 0.46, 0.44, 0.42 0.45, 0.44, 0.38

CIAT All 0.04, 0.03, 0.03 0.04, 0.03, 0.03

OIET All 0.06, 0.04, 0.02 0.03, 0.04,0.04

Hexazinone All 0.018, 0.014, 0.016 0.019, 0.014, 0.015

Simazine All 0.0099, 0.0067, 0.0068 0.0097, 0.0067, 0.0067

Metolachlor All 0.023, 0.018, 0.018 0.022, 0.018, 0.015

Results -- Herbicides (part II)

Herbicide Target Date Intake(ug/L)

Finished(ug/L)

2,4-D Waterhyacinth & alligatorweed

8/28 & 8/30

0.115, 0.013 0.0096, 0.0053

Endothall hydrilla -- -- --

Fluridone hydrilla All 0.103, 0.114, 0.223 0.108, 0.108, 0.169

Conclusions

• Limited evidence of the presence of waste water indicators

• Heavily used herbicides are found in low concentrations in the Ross Barnett Reservoir and were not removed by the drinking water treatment process then in place at the O.B. Curtis plant.

• Some herbicides used in the reservoir for aquatic vegetation control are found in the lower end of the Ross Barnett Reservoir and also were not removed by the treatment process.