Cumulative Effects Analysis of the Water Quality Risk of Herbicides Used for Site Preparation in the Central North Island, New Zealand

Abstract

Herbicide use varies both spatially and temporally within managed forests. While information exists on the effects of herbicide use on water quality at the site and small catchment scale, little is known about the cumulative effects of herbicide use at the landscape scale. A cumulative effects analysis was conducted in the upper Rangitaiki catchment (118,345 ha) in New Zealand, to determine the risk to water quality from two herbicides commonly used for post-plant weed control: terbuthylazine and hexazinone. Data from a 12.5 ha catchment study within the Rangitaiki Basin, where these herbicides were aerially applied in two consecutive years, were used to model herbicide concentrations entering the Rangitaiki River for the remaining treated areas in the catchment for the same two spray seasons. A spreadsheet model routed herbicide residues from their point of entry into the river to a flow gauge on the Rangitaiki River. Modeling of chemical residue loadings and concentrations of terbuthylazine and hexazinone indicated that potential herbicide residues in stream waters would be mainly below analytical detection limits and pose no risk to the aquatic environment or human health and safety. Safety factors for drinking water quality standards, aquatic organisms, and human Acceptable Daily Intake levels were very large.

Use of literature mining for early identification of emerging contaminants in freshwater resources

“…Also, words are used in many different ways in a sentence, such as the words 'new' and 'first' , which leads the pattern to extract false positives. For example, 'new' could be part of a region´s or city´s name, such as 'New Zealand' in the abstract published by Neary and Baillie [50]. The word 'first' is also used in many articles as a numerical transition word, for example in the abstract by Sharma and Malaviya [51].…”

Early Warning and Forecasting System of Water Quality Safety for Drinking Water Source Areas in Three Gorges Reservoir Area, China

“…Presently, models and systems for monitoring and predicting water quality safety have become focuses in the field of water resource protection and management [11][12][13][14][15]. He et al developed an integrated geographic information system based on a water pollution management information system for the TGRA that could predict the transfer and diffusion processes of pollutants and support water pollution emergency management [16].…”