Risk Assessment for Safe Drinking Water Supplies - Global Drinking Water Management and Conservation - page 114

that considers the safety of all nearby water bodies including groundwater. All
CFAOs are required to keep records of the quantity of manure produced and how
the manure was utilized, applied to land, sold to third parties for the manufacture of
fertilizers, or used for methane generation as an energy source.
Apart from the regulatory requirements, there are voluntary guidelines from the
U.S. Department of Agriculture (USDA) for best management practices (BMPs) on
farms as well as tax incentives for demonstrating the implementation of BMPs.
There are

financial and technical assistance programs for implementing nutrient
management plans as well as environmental education programs. And there are
performance measures for the implementation of the “ Uni ed National Animal

Feeding Operations Strategy ” (USEPA 2002 ).

6.2.2.2 Nonpoint Source Pollution

Nonpoint sources of pollution, also called diffused pollution, mostly originate from
unknown origins and locations; it is the pollution that shows up downstream; it may
include pollution due to the death of wild animals in water courses at unknown
locations, or even bird feces, as noted in Chap. 2 . Nonpoint sources of pollution
associated with surface runoff include sediments, nutrients, pesticides, pathogens,
metals, oils, and many chemical contaminants entering water bodies from unknown
locations. Controlling nonpoint sources of pollution is rather dif

cult and compli-

cated because of its diffused characteristics and dif culty in pinpointing the origin

of contaminants flowing to surface waters. Watershed management and imple-

menting BMPs are considered effective tools for nonpoint source pollution control.

6.2.2.3 Ecological Risk Assessment

To deal with nonpoint source pollution, the U.S. EPA recommends the application
of ERA to watershed management (USEPA 1998). As de

ned by the U.S. EPA,

“ c information in order to

evaluate the likelihood that adverse ecological effects may occur or are occurring as
a result of exposure to one or more stressors

ERA is a process to collect, organize, and analyze scienti

(USEPA 1998 ). Watershed ERA
consists of a combination of one or more ERA methodologies and watershed
management approaches. Table 6.1 shows major steps for a watershed ERA
framework developed by the U.S. EPA (USEPA 2007 ).
Step 1: Problem formulation is de

”

ned as an integrated framework for risk
assessment, including assessment of conceptual models and analysis plan. The
conceptual models describe the various physical, chemical, and biological stressors,
their sources, assessment endpoints and the possible pathways and also disclose
how the assessment endpoints respond to the stressors via possible pathways, as
shown in Fig. 6.1 (USEPA 2007 ).