Variations in statewide water quality of New Jersey streams, water years 1998-2009

Heckathorn, Heather A.; Deetz, Anna C.

doi:10.3133/sir20125047

Cited by 2 publications

(2 citation statements)

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“…• Keep all data and employ statistical tools for computing concentration statistics (median and percentile concentrations) such as the Kaplan-Meier method on left-censored data (Helsel, 2012). Such statistical methods involve no assumptions about the underlying distribution of a dataset and can handle complex datasets with multiple reporting levels and detected concentrations that are less than the reporting level (for example, Heckathorn and Deetz, 2012;Berndt and Crandall, 2009).…”

Section: Other Modifications To Detection-level Determinations and Damentioning

confidence: 99%

Use of set blanks in reporting pesticide results at the U.S. Geological Survey National Water Quality Laboratory, 2001-15

Medalie¹,

Sandstrom²,

Toccalino³

et al. 2019

Scientific Investigations Report

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Section: Other Modifications To Detection-level Determinations and Damentioning

confidence: 99%

Use of set blanks in reporting pesticide results at the U.S. Geological Survey National Water Quality Laboratory, 2001-15

Medalie¹,

Sandstrom²,

Toccalino³

et al. 2019

Scientific Investigations Report

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“…Graves et al (2005) used the nonparametric test to determine differences of nutrient concentrations in runoff from select land use categories in Florida's Indian River Lagoon watershed. Heckathorn and Deetz (2012) Equations 3,4,5,6,and 7: (3) where: N = total number of observations n i = size of random sample k = random sample from population…”

Section: Objectivementioning

confidence: 99%

A Spatial and Temporal Analysis of Land Use and Water Quality in Southern Miami Dade County

Londono¹

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County. The following research questions and hypothesis will guide this thesis.• Question: What is the status of nutrient concentrations in the canals of southern Miami Dade County that flow through agricultural lands? 2 o Hypothesis: Nutrient concentrations in the canals will differ, considering the different land use practices. There will be differences between canals that flow through urban-residential areas and canals that flow through agricultural lands. Certain types of agricultural practices may influence water quality at specific sites. Those land use practices related to specific sites will be identified.• Question: Do the nutrient concentrations among the canals differ from each other?o Hypothesis: The nutrient concentrations across not only the canals, but across canal sites will differ considering the different land use compositions at each site.• Also, the higher levels of phosphorus in surface waters lead to the increased growth of organisms such as algae and duckweed, which changes the habitat of aquatic and nonaquatic wildlife (Bates et al. 2002). In the case of nitrogen, it is mostly found as total organic nitrogen (TON) in the Everglades and near-shore waterbodies, but oxidized forms of inorganic nitrogen such as nitrate, nitrite, and ammonia have been observed as well (Briceño et al. 2013;Lietz 1999 where: X _ is the sample mean n is the observed sample sizeThe sample is then ordered from smallest to largest as shown below,Also, for the observed sample size n, coefficients for the Shapiro-Wilk test must be looked up which are provided in statistical textbooks and integrated in computer statistical software (Conover 1999). The Shapiro-Wilk test statistic T 3 is derived as shown in Equation 2:where: X SFWMD 1995). For NH3-N, both thresholds were used for the summary statistics table.These NOx-N and NH3-N nutrient criteria were also used by Carey et al. (2011) for the Biscayne Bay watershed study regarding nutrient discharges into the bay. Objective 2The second objective is to determine whether or not the water quality stations have similar distribution functions of nutrient concentrations of TP, NOx-N, and NH3-N.In order to accomplish this, the data for each corresponding water quality station need to be ranked by degree of nutrient impairment. where: N = total number of observations n i = size of random sample k = random sample from populationwhere: i = 1, 2, …, k X ij = ith random sample of size n i R(X ij )= rank assigned to X ijThe test statistic T is defined by Equation 5 as: If the null hypothesis can be rejected, then it can be determined which pairs of water quality stations differ by employing a pairwise comparison procedure that utilizes the following inequality equation, Equation 8 devised by Sachs (1997):where: R i and R j are the rank sums of two samples If this inequality is satisfied then it can be said that water quality stations i and j are different in terms of their distributions. Also, box-plots depicting the nutrientconcentrations for each water quality station in each time...

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Variations in statewide water quality of New Jersey streams, water years 1998-2009

Cited by 2 publications

References 1 publication

Use of set blanks in reporting pesticide results at the U.S. Geological Survey National Water Quality Laboratory, 2001-15

Use of set blanks in reporting pesticide results at the U.S. Geological Survey National Water Quality Laboratory, 2001-15

A Spatial and Temporal Analysis of Land Use and Water Quality in Southern Miami Dade County

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