English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

A study was conducted in 2014–15 by the U.S. Geological Survey (USGS), in cooperation with the Municipality of Caguas, to determine if changes in the stream sanitary quality during base-flow conditions have occurred since 1997–99, when a similar study was completed by the USGS. Water samples were collected for the current study during two synoptic surveys in 2014 and 2015. Water samples were analyzed for fecal and total coliform bacteria, nitrate plus nitrite as nitrogen, nitrogen and oxygen isotopes of nitrate, and human health and pharmaceutical products. Water sampling occurred at 39 stream locations used during the 1997–99 study by the USGS and at 11 additional sites. A total of 151 stream miles were classified on the basis of fecal and total coliform bacteria results. The overall spatial pattern of the sanitary quality of surface water during 2014–15 is similar to the pattern observed in 1997–99 in relation to the standards adopted by the Puerto Rico Environmental Quality Board in 1990. Surface water at most of the water-sampling sites exceeded the current standard for fecal coliform of 200 colonies per 100 milliliters adopted by the Puerto Rico Environmental Quality Board in 2010. The poorest sanitary quality was within the urban area of the Municipality of Caguas, particularly in urban stream reaches of Río Caguitas and in rural and suburban reaches bordered by houses in high density that either have inadequate septic tanks or discharge domestic wastewater directly into the stream channels. The best sanitary quality occurred in areas having little or no human development, such as in the wards of San Salvador and Beatriz to the south and southwest of Caguas, respectively. The concentration of nitrate plus nitrite as nitrogen ranged from 0.02 to 9.0 milligrams per liter, and did not exceed the U.S. Environmental Protection Agency drinking-water standard for nitrate as nitrogen of 10 milligrams per liter. The composition of nitrogen and oxygen isotopes of nitrate indicates that the origin of nitrate in the streams is most likely animal and human waste. A baseline was established for the concentrations of selected human health and pharmaceutical products at stations in some of the streams within the Municipality of Caguas. Thirty-eight human health and pharmaceutical products were present at or above the measurement detection level. Introduction The Autonomous Municipality of Caguas (referred to herein as the Municipality of Caguas) is located south of San Juan at the eastern end of the Cordillera Central mountain range and between the Sierra de Cayey and Sierra de Luquillo minor mountain ranges (fig. 1). Caguas, with an area of 58.7 square miles (mi2) and a population of about 143,000 in 2015, is part of the larger San Juan metropolitan area. The average population density is about 2,394 persons per mi2. The maximum land surface altitude in the Municipality of Caguas (2,887 feet [ft] above mean sea level) is at Cerro Lucero (fig. 1). A study conducted during 1997–99 by the U.S. Geological Survey (USGS), in cooperation with the Municipality of Caguas, classified the streams within the municipal territory according to their sanitary quality during base-flow conditions (Gómez-Gómez and others, 2001). The classification of sanitary quality was based on whether the concentration of fecal coliform and total coliform exceeded the prevalent standards of the Puerto Rico Environmental Quality Board (PREQB) for these parameters during 1997–99 in successive samples (Junta de Calidad Ambiental de Puerto Rico, 1990). Water samples from 40 stream sites within the Municipality of Caguas were analyzed for fecal coliform bacteria. The study indicated that 28 percent of stream miles analyzed within the territory were classified as having poor sanitary quality. Only 9.6 percent of the total stream miles classified were of good sanitary quality; the remaining 62.4 percent were classified as having fair or acceptable sanitary water quality. Approximately 26 stream miles (mi) out of a total of 163 mi (about 16 percent) were not classified because of insufficient data. 2 Sanitary Quality of Surface Water During Base-Flow Conditions in the Municipality of Caguas, Puerto Rico As part of the 1997–99 study, the surface waters within the Municipality of Caguas were classified in terms of their sanitary quality according to the water-quality standards for surface waters in Puerto Rico established and implemented by the PREQB (Junta de Calidad Ambiental de Puerto Rico, 1990). The water-quality standards implemented by PREQB are based on the designated use of the surface waters; for example, fishing, raw water source for public-supply, and secondary contact for recreation, among other uses. All perennial fresh surface waters in Puerto Rico inland of their estuaries are classified as Class SD waters. In the 1997–99 study, the sanitary quality standard for Class SD surface water according to the PREQB (Junta de Calidad Ambiental de Puerto Rico, 1990) was based on the fecal coliform or total coliform indicator bacteria concentration as follows: the geometric mean concentration of at least five samples in sequential order shall not exceed 10,000 colonies per 100 milliliters (mL) for total coliform bacteria or 2,000 colonies per 100 mL for fecal coliform bacteria, and not more than 20 percent of the samples (1 in a set of 5) shall exceed 400 colonies per 100 mL of fecal coliform bacteria (Junta de Calidad Ambiental de Puerto Rico,1990). During 1997–99, the contamination sources that affected stream sanitary quality during base-flow conditions were distinct for urban and rural areas (Gómez-Gómez and others, 2001). In urban areas, probable major sources of fecal contamination were the illegal discharge of sewage to stormwater drains, overflows from sewer mains into the stormwater drains because of clogged mains, ruptured sewer mains, and seepage from sewer mains into the local aquifer. In rural areas, major sources of fecal contamination included gray-water discharge from residential and commercial establishments along stream channels, septic tank seepage or overflows, fecal contamination directly into streams from unfenced livestock, and runoff from restrained livestock pens near stream courses. Another potential source of fecal contamination considered during the 1997–99 study was runoff and groundwater seepage from the municipal landfill at Barrio Turabo (fig. 2; Gómez-Gómez and others, 2001). Gómez-Gómez and others (2001) also delineated the potential contaminant sources from unsewered rural communities in proximity to stream courses, particularly along stream segments with fecal coliform concentrations below 2,000 colonies per 100 mL. It is likely that the indicator bacteria might have become affected by household wastewater discharges, rendering them unable to grow and form colonies because of structural or metabolic changes associated with exposure to untreated wastes (American Public Health Association, American Public Works Association and Water Environment Federation, 1998). Housing communities bordering the riparian zone or dense housing developments, generally having one or more housing units per 1/5th acre and located within 300 feet (ft) of stream courses are potential sources of fecal contamination to streams from “gray-water” discharge and septic tank seepage. The Municipality of Caguas adopted and implemented measures to improve the sanitary quality of streams and to comply with the Commonwealth of Puerto Rico State and Federal standards at those streams for which the study by Gómez-Gómez and others (2001) indicated high fecal contamination during 1997–99. After a 15-year period in which the population increased from 140,500 to 142,900 (U.S. Census Bureau, 2012), the Municipal Government of Caguas sought to determine the Cerro Lucero

scientific investigations report

Sanitary quality of surface water during base-flow conditions in the Municipality of Caguas, Puerto Rico, 2014–15: A comparison with results from a similar 1997–99 study