Comparison of standard methods for determining the color of water in several countries

Determination of water color is one of the important indicators in assessing water quality. This article compares the available methods used to determine water color according to the international standard ISO 7887 or according to standard methods published by American organizations. The comparison takes into account the specific application of the legislation in the selected countries.

A Low-Cost Digital Colorimetry Setup to Investigate the Relationship between Water Color and Its Chemical Composition

Developments in digital image acquisition technologies and citizen science lead to more water color observations and broader public participation in environmental monitoring. However, the implications of the use of these simple water color indices for water quality assessment have not yet been fully evaluated. In this paper, we build a low-cost digital camera colorimetry setup to investigate quantitative relationships between water color indices and concentrations of optically active constituents (OACs). As proxies for colored dissolved organic matter (CDOM) and phytoplankton, humic acid and algae pigments were used to investigate the relationship between water chromaticity and concentration. We found that the concentration fits an ascending relationship with xy chromaticity values and a descending relationship with hue angle. Our investigations permitted us to increase the information content of simple water color observations, by relating them to chemical constituent concentrations in observed waters.

ENVIRONMENTAL ASSESSMENT OF WATER QUALITY IN THE ONEGO LAKE URBAN TRIBUTARY BY CHEMICAL INDICATORS

Introduction. The Lososinka River is an urban tributary of Lake Onego, the lower reaches of which flow through the territory of Petrozavodsk city, receiving untreated drains of the city’s storm sewers. The river enters the Petrozavodsk Bay of Lake Onego, which is used as a source of public drinking water supply in the city. Methods. During the 2015 open water period, the oxygen concentration, total iron, color, pH, total suspended matter, biochemical oxygen demand (BOD5), content of oil products, and dichromate chemical oxygen demand were measured by standard methods in the water of the background and urban areas of the Lososinka River. Results. In the river water, high values of water color (132 mg/l Cr-Co), total iron (1.5 mg/l), dichromate chemical oxygen demand (23 mgO/l) were revealed, which is associated with the geochemical peculiarities of the surface waters in Karelia, enriched in the humic matter. Seasonal increases in the concentrations of these indicators were associated with floods. The oxygen saturation of the water reached 90% due to the fast current and riffles. The indicators of water pollution include total phosphorous (60 μg/l), mineral phosphorous (40 μg/l), BOD5 (1.5 mgO2/l), suspended matter (25.5 mg/l), and content of oil products (0.02 mg/l). Seasonal changes in these indicators were not associated with the hydrological regime of the river. In the storm sewers of the city, the maximum permissible concentrations for BOD5 are exceeded by 4 times, and for oil products — by 15 times. The Kruskal–Wallis test showed that all the studied chemical indicators in the urban and background areas of the river do not have significant differences. Conclusion. Water quality in the Lososinka River is considered satisfactory in terms of most of the studied parameters. According to the total iron content, the water is characterized as polluted, and according to water color, the river water is classified as dirty. The maximum permissible concentrations for total iron in the background and urban areas of the river were exceeded by 10 times. The standards for water quality adopted in the Russian Federation and the maximum permissible concentrations for total iron and water color are inapplicable for the water bodies in Karelia with high background values of these indicators. The trophic status of the river corresponds to the eutrophic state. Good saturation of the river water with oxygen hinders water pollution in the city territory due to self-purification processes.

The visual ecology of selective predation: Are unhealthy hosts less stealthy hosts?

Predators can strongly influence disease transmission and evolution, particularly when they prey selectively on infected hosts. Although selective predation has been observed in numerous systems, why predators select infected prey remains poorly understood. Here, we use a model of predator vision to test a longstanding hypothesis as to the mechanistic basis of selective predation in a Daphnia-microparasite system, which serves as a model for the ecology and evolution of infectious diseases. Bluegill sunfish feed selectively on Daphnia with a variety of parasites, particularly in water uncolored by dissolved organic carbon. The leading hypothesis for selective predation in this system is that infection-induced changes in the appearance of Daphnia render them more visible to bluegill. Rigorously evaluating this hypothesis requires that we quantify the effect of infection on the visibility of prey from the predator’s perspective, rather than our own. Using a model of the bluegill visual system, we show that the three common parasites, Metschnikowia bicuspidata, Pasteuria ramosa and Spirobacillus cienkowskii, increase the opacity of Daphnia, rendering infected Daphnia darker against the background of downwelling light. As a result of this increased brightness contrast, bluegill can see infected Daphnia at greater distances than uninfected Daphnia – between 19-33% further, depending on the parasite. Pasteuria and Spirobacillus also increase the chromatic contrast of Daphnia. Contrary to expectations, the visibility Daphnia was not strongly impacted by water color in our model. Our work generates hypotheses about which parasites are most likely affected by selective predation in this important model system and establishes visual models as a valuable tool for understanding ecological interactions that impact disease transmission.

Matacong Island: A Short History of a Small Island on the West Coast of Africa

This article aims to examine how Matacong Island, a small island just off the coast of the Republic of Guinea, West Africa, was claimed its possession by local chiefs, how it was leased to and was used by European and Sierra Leonean merchants, and how it was colonized by Britain and France in the 19th century. In 1825 the paramount chief of Moriah chiefdom agreed to lease the island to two Sierra Leonean merchants, and in 1826 it was ceded to Britain by a treaty with chiefs of the Sumbuyah and Moriah chiefdoms. Since the island was considered as a territory exempted from duty, British and Sierra Leonean merchants used it as an important trading station throughout the 19th century. Major exports of Matacong Island included palm kernels, palm oil, hides, ivory, pepper and groundnuts, originally brought by local traders from the neighboring rivers, and major imports were tobacco, beads, guns, gunpowder, rum, cotton manufactures, iron bars and hardware of various kinds. In 1853 alone, some 80 vessels, under British, American, and French flags, anchored at Matacong Island. By the convention of 1882, Britain recognized the island as belonging to France. Although the convention was never ratified, it was treated by both countries as accepted terms of agreement. The article considers various dynamics of usage, property, and territorial possession as relates to the island during the 19th century, and reveals how complex they were, widely making use of the documents of The Matacong Island (West Africa) Papers at the University of Birmingham Library in Britain. The collection purchased by the library in 1969 is composed of 265 historical documents relating to Matacong Island, such as letters, agreements, newspaper-cuttings, maps and water-color picture

Eksperimen Bahan Makanan Sebagai Alternatif Cat Warna Air

This research aims to describe the process of creating water color paints and the resulting colors made of foodst materials. The making of this water color paint through several stages, such stages are, observation, exploration, experimental, and quality testing. This experiment focused on foodstings as dye paint making materials. The exploration stage is about the materials used as additives, pigments, solvents, and binders in paints. Experimental stages in the form of making groceries into dye paints. The quality test stage is the process of comparing the quality of the experiment's color paint and the factory-made color paint. The concept of making color paint explores ingredients from food namely, kanji flour, baking soda, vinegar, food coloring, and water. And aids like, bowls and spoons, plastic containers, and toothpicks. The paint is realized into the form of a painting using aquarel painting technique.

Mangrove Phenology and Water Influences Measured with Digital Repeat Photography

The intertidal habitat of mangroves is very complex due to the dynamic roles of land and sea drivers. Knowledge of mangrove phenology can help in understanding mangrove growth cycles and their responses to climate and environmental changes. Studies of phenology based on digital repeat photography, or phenocams, have been successful in many terrestrial forests and other ecosystems, however few phenocam studies in mangrove forests showing the influence and interactions of water color and tidal water levels have been performed in sub-tropical and equatorial environments. In this study, we investigated the diurnal and seasonal patterns of an equatorial mangrove forest area at an Andaman Sea site in Phuket province, Southern Thailand, using two phenocams placed at different elevations and with different view orientations, which continuously monitored vegetation and water dynamics from July 2015 to August 2016. The aims of this study were to investigate fine-resolution, in situ mangrove forest phenology and assess the influence and interactions of water color and tidal water levels on the mangrove–water canopy signal. Diurnal and seasonal patterns of red, green, and blue chromatic coordinate (RCC, GCC, and BCC) indices were analyzed over various mangrove forest and water regions of interest (ROI). GCC signals from the water background were found to positively track diurnal water levels, while RCC signals were negatively related with tidal water levels, hence lower water levels yielded higher RCC values, reflecting brownish water colors and increased soil and mud exposure. At seasonal scales, the GCC profiles of the mangrove forest peaked in the dry season and were negatively related with the water level, however the inclusion of the water background signal dampened this relationship. We also detected a strong lunar tidal water periodicity in seasonal GCC values that was not only present in the water background, but was also detected in the mangrove–water canopy and mangrove forest phenology profiles. This suggests significant interactions between mangrove forests and their water backgrounds (color and depth), which may need to be accounted for in upscaling and coupling with satellite-based mangrove monitoring.