Water quality trends in the last decade for ten watersheds dominated by diffuse pollution in Québec (Canada)

Abstract

The aim of this work is to evaluate and discuss river water quality trends over the last decade in ten watersheds where diffuse pollution represents more than half of the annual load of phosphorus (P) and nitrogen (N). Trend analyses taking into account flow data indicate a significant reduction of total P in eight rivers, of ammonia N in five rivers, of nitrate + nitrite in four rivers, of total filtered N in three rivers and of suspended solids in two rivers. An increase of turbidity was observed in four rivers and, for fecal coliforms, no trends. P decrease can be explained by reduced mineral P inputs on cropped lands related to means such as agro-environmental fertilization plans and addition of phytase in pig and poultry feed. However, for seven of them, median P concentrations remain at least two times greater than the Québec water quality guideline for protection of rivers against eutrophication. Concentrations of other parameters remain problematic in some rivers too. These results indicate the need to continue the efforts for further diffuse pollution reduction. Future work should better quantify actions taken at the watershed scale to reduce diffuse pollution.

Phytase, a New Life for an “Old” Enzyme

“…Initial success has been documented in controlled animal experiments and in open, large-scale ecological studies. Impressively, phytase supplementation in animal feed has been found to contribute to the reduction of total phosphorus concentrations over the past decade in eight of ten rivers that are dominated by diffuse pollution in Quebec (Canada) (156). Although it took 20 years after the first commercial launch of phytase in 1991 for the phytase market to reach approximately $350 million per year, several factors likely will expand phytase application to much greater values.…”

Evaluating the impacts of climate change and crop land use change on streamflow, nitrates and phosphorus: A modeling study in Bavaria

“…In basins where agricultural activities dominate, it is common for the quality of water to be compromised (Green et al, 2014;Patoine et al, 2012;Volk et al, 2009). For example, in Denmark, Nielsen et al (2012) found a high correlation between the amount of agricultural land and the total nitrogen (N) and total phosphorus (TP) concentrations in adjacent lakes.…”