Macroinvertebrates As Bioindicators of Water Pollution in Streams Draining Dairy Farming Catchments

Abstract

Runoff from intensive dairy farming systems can impair the quality of catchment waters, with potential ecological and human health implications. A water quality study was carried out in three streams in a predominantly dairy farming region, with the aim of assessing the effects of diffused-and point-sourced inputs on a number of water quality parameters and benthic macroinvertebrates. The results showed significant increases in streamwater biochemical oxygen demand (BOD), ammonium-nitrogen (m-N) and molybdate reactive phosphorus (MRP) concentrations between the farm reaches. These changes in water quality appeared to be due largely to the point-sourced inputs from farmyards, and had a significant effect on the ability of the water to support a healthy and diverse community of invertebrates. The results also showed that concentrations of dissolved oxygen (DO) and ammonium in streamwater were the two most important parameters studied that were inversely related to the invertebrate scores.

Farmyard point discharges and their influence on nutrient and labile carbon dynamics in a second order stream draining through a dairy unit

“…Similarly, farmyards have been shown to represent an important source of microbial contamination (Kay et al, 2003). There are direct local influences of farmyards on stream water quality (see Hooda et al, 2000b). Runoff from impervious hardstanding areas and farm tracks often displays a marked episodic response in relation to hydro-logical events with the degree of contamination dependent upon various combinations of factors (Edwards et al, this issue).…”

“…This general assumption is evident from a number of recent reviews and forms the underlying basis for the application and use of loss coefficients (Hooda et al, 2000a;Vanni et al, 2001;Woli et al, 2002;Salvia-Castellvi et al, 2005). Recent evidence suggests that under certain circumstances, point sources, which include piped flows from farmyards, silage effluents and domestic septic systems (Hooda et al, 2000b), together with surface runoff from areas of hardstanding (Hively et al, 2005) may also contribute significantly. While these various sources contribute cumulatively to the total catchment export loading there is also the possibility for impacts, including increases in biochemical oxygen demand and decline in benthic macroinvertebrate species, on receiving headwaters (Hooda et al, 2000b).…”

Impacts of Pig Manure-Based Liquid Fertilizer Agricultural Application on the Water Quality of Agricultural Catchment

“…Generally, when there is no rainfall, the level of nutrients including BOD remains within normal range in surface waters unless farm effluents are discharged directly into streams. This effluent may have even greater nutrient concentration if there has been no rainfall event [24]. In addition, the impact intensity of land use on water quality was as great as the amount of surplus nutrient in cropland from the respective drainage watershed [3].…”

Microbial and nutrient contaminants of fresh and coastal waters

“…The role of nitrogen (N) in eutrophication is less clear, however, there are other N related water quality issues, such as compliance with the nitrate-N limit (Nitrate Directive 91/676/EEC), and impacts of reduced-N on aquatic ecology. Excess inputs of either forms of the reduced N (NH 3 -N or NH 4 -N) can seriously impair aquatic ecology through direct toxicity (NH 3 ) and diminished dissolved oxygen (due to oxidation of NH 4 ) supply impacts upon invertebrates (Hooda et al, 2000b) and fish (Camargo and Alonso, 2006). N and P arise generally from intensive agriculture (Hooda et al, 2000a;Withers and Lord, 2002); however, their inputs from sewage treatment works can be equally important in densely populated catchments (Jarvie et al, 2006).…”

“…Direct discharges of such effluents from animal housing areas can also contribute significant quantities of faecal bacteria and NH 4 -N ( Monaghan and Smith, 2004). Together, these livestock farm effluents have been known to degrade ecological quality of receiving waters (Hooda et al, 2000b). Ecological status of waters has gained much more significance in recent years because of the Water Framework Directive (Directive 2000/60/EC), which places ecological quality protection at the centre of water management strategies.…”