Field Determinations of Pentachlorophenol in Water Using UV/Vis Spectroscopy

Pentachlorophenol (PCP) is an organochloride pesticide banned in many countries due to its broad-spectrum toxicity. Current methods for monitoring PCP in environmental water require expensive laboratory equipment, limiting field monitoring. Two field methods for screening the concentration of PCP in environmental water are described herein. The first involves filtering the sample and calculating the indicative concentration from the absorbance at 320 nm. Alternatively, the sample can be acidified with concentrated hydrochloric acid to produce a fine suspension. This cloudy solution can be matched to a photo card for field estimation of concentration, or calculated more accurately from the absorbance at 450 nm. The useable ranges for these methods are 2 ppb to 100 ppm for the un-acidified method and 4 ppm to 1000 ppm for the acidified method. Results indicate that aquatic humic substances and natural turbidity present in environmental water do not compromise the results.