**2.3 Assessing status and trends**

*Water Quality - Science, Assessments and Policy*

**Physical habitat parameters**

C)

Dissolved oxygen—DO (mg/L)

Total organic carbon—TOC (%) % Silt/clay (grainsize) **Water-quality parameters** Chlorophyll *a* (μg/L) Ammonium (mg N/L) Nitrate plus nitrite (mg N/L)

Dissolved inorganic nitrogen—

Total nitrogen—TN (mg N/L) Dissolved inorganic phosphate—

Total phosphorus—TP (mg P/L)

Diversity and abundance of fish **Human health indicators**

Diversity and abundance of benthic macroinvertebrates

PCBs, PBDEs and PFCs in fish tissue (Great Lakes only)

*reported as dry weight of sediments and wet weight of tissue.*

Temperature (°

Secchi depth (m)

Nitrite (mg N/L)

DIN (mg N/L)

DIP (mg P/L)

*Hyalella azteca*

*a*

**Table 1.**

**Biotic conditions**

**Sediment toxicity** Amphipod survival bioassay Estuarine test organisms: *Leptocheirus plumulosus Eohaustorius estuarius* Great Lakes test organism:

Salinity (ppt)

pH

**National Coastal Condition Assessment Indicators**

**Physical habitat parameters Ecological contaminants in sediments and fish tissue**<sup>a</sup>

mirex, trans-nonachlor

Zn

**Metals (μg/g)**: Ag, Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Sn, Tl,

**PAHs (ng/g)**: acenaphthene, acenaphthylene, anthracene, benz(a) anthracene, benz(a,e)pyrene, benzo(b,k,b+k)flouranthene, benzo(g,h,i)perylene, biphenyl, chrysene, dibenz(a,h) anthracene, fluoranthene, fluorene, indeo(1,2,3-c,d)pyrene, naphthalene, 1-methylnaphthalene, 2-methyl naphthalene, 2,6-dimethylnaphthalene, 2,3,5-trimethylnaphthalene, perylene, phenanthrene, 1-methylphenanthrene, pyrene, total PAHs

**PCB congeners (ng/g)**: 8, 18, 28, 29, 44, 52, 66, 87, 101, 105, 118, 128,

**Pesticides (ng/g)**: aldrin, chlordane (alpha-, gamma-, oxy-), dieldrin, dibenzothiophene, DDD (2,4'; 4,4'), DDE (2,4'; 4,4'), DDT (2,4'; 4,4'), endosulfan I & II, endrin, heptachlor, heptachlor epoxide, hexachlorobenzene, hexachlorohexane (alpha-, beta-, delta-), lindane,

138, 153, 170, 180, 187, 195, 201, 206, 209, total PCBs

The field data were submitted as either physical or electronic data sheets to NCCA headquarters for compilation. Preserved water, sediment, and fish samples were shipped to approve national or state laboratories for analysis and results were submitted to NCCA headquarters. Each site generated hundreds of field and laboratory data values that were organized into files by type (e.g., field data, water quality data, benthic census data, etc.), and maintained as "raw files" in a centralized database by information management specialists. The raw files were then subjected to a stringent two-phase QA review process, first checking for basic compliance with submission requirements (e.g., proper units, range checks, and conformity with standard taxonomic terminology). Any revisions to the raw files were carefully documented, and finalized files were made available at the NCCA

*Indicators measured in the National Coastal Condition Assessment (NCCA) surveys.*

Mercury in fish plugs; algal toxins (microcystin and cylindrospermopsin) and enterococcus in water

*National Oceanic and Atmospheric Administration National Status and Trends Program analytes. Concentrations* 

One of the hallmarks of the NCCA, and the NCA which preceded it, has been the emphasis on the cooperation and participation of the states and tribes in planning and conducting the assessment within their respective jurisdictions. Not only are states and tribes key to survey implementation, they are the entities responsible

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public website [26].

Following the lead of earlier EPA coastal surveys, the NCCA approach had two primary goals regarding assessment: (1) evaluate the *status* of four major components of coastal ecosystems—the water column, sediment, and benthic and fish communities, and (2) ascertain how conditions *change over time (i.e., trends)*. For each of the key assessment components, conditions were evaluated based on a suite of core indicators and indices constructed from them. For instance, water quality was assessed using five measured indicators (concentrations of nutrients, chlorophyll, and dissolved oxygen, and water clarity) and a water quality index was then crafted from the five components. The assessment process first evaluated conditions at each site, rating each indicator and index as good, fair, or poor based on regionally determined assessment thresholds. Details regarding the indicators, indices, and thresholds used in assessments are presented in Section 3 of this chapter.

Once sites were evaluated, regional and national conditions were calculated. Recall that the survey design process had assigned each site a weighting factor equal to the area represented by the station. Regional assessments were then expressed as the percent of the region in good, fair, poor, or unassessed condition. For instance, the percent area of the Pacific coast in good condition was simply calculated as the sum of weighting factors associated with Pacific sites rated as good, divided by the total area of the Pacific coastal region (sum of all Pacific site weights). Assessments were calculated for the nation, for the five primary reporting regions (**Figure 2**), and for any state or designated research area containing a statistically-sufficient number of sites.

The survey design procedure further provided a measure of the uncertainty in the condition estimates, expressed as the 95th percentile confidence interval (CI), which was calculated as the binomial proportion confidence interval adjusted for possible spatial gradients in indicator measurements [23, 27]. Operationally, the confidence intervals were calculated using a complex computer-intensive algorithm, coded in the R-programing language, available at EPA's Aquatic Resource Monitoring website [25].

As the number of surveys conducted increases, the NCCA documents change over time. Typically, trends have been evaluated by analyzing what happens at an individual location, much as a physician monitors trends in the weight of an individual patient. In contrast, trends for NCCA were evaluated at the population level, i.e., trends in the proportion of sites in good condition. These population level trends were evaluated by noting statistically significant changes, i.e., condition estimates displaying non-overlapping CIs, determined over a series of comparable surveys. Since the early 1990s, coastal survey methods have evolved significantly over time. In some cases, new analyses can be applied to old data. In other cases, methodological differences have precluded trend analyses over the entire 30-year period. Eventually, trends in national assessments will reflect only NCCA surveys conducted from 2010 onward.
