Site-specific risk assessment and management of point and diffuse sources - Environmental Deterioration and Contamination: Problems and their Management - page 364

of reducing nutrient input by controlling the use of mineral and organic fertilizers (e.g.,
Nitrate Directive in the EU). Land use conversions (reforestation, pasture or wetland
development from agricultural land) affect the soil water balance as well as the erosive
potential. Cultivation changes (tillage direction, conservation tillage, strip cropping,
mulching, contouring) have impact on the soil loss values. These are source controlling
measures by reducing runoff and soil loss.
Delivery or transport control tries to reduce the transfer of pollutants from soil to
water bodies. Measures include floodplain rehabilitation and establishment of riparian
buffer zones along the riverbed, or the introduction of constructed wetlands. They are
implemented to retain pollutants during their transport in field and river bed. Their
impact also materializes in reducing flow velocity.
Efficiency of applied practices has been evaluated in different case study areas
(Campbell et al., 2004). Several studies have reported BMP effectiveness values for
reducing phosphorous loads. Because of varying hydrological and soil conditions,
the literature contains a wide range of factors associated with each BMP. Different
pollutants (nitrogen, phosphorus, pesticides, suspended solids and bacteria) have dif-
ferent sources, different pathways, and therefore, different potential control measures
(Campbell et al., 2004).
There are several studies to simulate the effectiveness of BMPs at different scales
(field or farm level as well as watershed scale). The most frequently applied model is the
soil and water assessment tool or SWAT (Neitsch et al., 2002). SWAT was found to be
one of the most suitable tools that can simulate water quality and the effect of nutrient
management as a result of the EUROHARP project, which was aimed at harmonizing
the modeling tools to quantify nutrient losses from diffuse sources (EUROHARP 2002-
2005). Because of cost and delayed responses to mitigation, measurement is most
reliable and informative at smaller scales, e.g., field and farm (Cherry et al., 2008).
Besides modeling, practical application of BMP concepts must be accompanied
by a cost-benefit analysis and economic feasibility study as well as legal regulation
(Zanou et al., 2003). There are BMP alternatives with nearly the same emission reduc-
ing efficiency, therefore costs can play an important role in decision-making. There
are areas with high economic or natural value, where land use form should not be
changed. Finally, farmers should be inspired in changing their management practices
by economic and/or legal programs (Herzog et al., 2008).
6 ASSESSMENT AND MANAGEMENT OF DIFFUSE SOURCES
FROM MINING
E. Vaszita
6.1 General characterization of diffuse pollution
from mining
Mining has polluted the surface and groundwater for centuries. Internationally it has
been recognized that diffuse source water pollution from mining seriously affects water
quality especially in terms of salinity, acidification and metal loading.
Legislative drivers in the European Union (such as the European Commission's
Water Framework Directive 2000/60/EC) demand basin-scale inventories of diffuse