This paper discusses the results of a study done in River Thome which is located in Nairobi county in Kenya. The purpose of the study was to establish whether the river water meets the set quality standards for surface water and irrigation water. It was established that the river water has been negatively impacted by wastewater from various human activities along the river stretch studied. The study analyzed levels of selected physico- chemical properties of Kasarani stretch of River Thome. Water samples were collected for laboratory analysis from five different stations. Mean level ranges of the physico-chemical properties were as follows: Water temperature, 18.1-27.3°C pH, 6.6-8.1; dissolved oxygen (DO), 0-10.8 mg/L; total alkalinity, 25-298.0 CaCO3 mg/L; biological oxygen demand (BOD), 0.1-118.9 mg O2 /L, and electrical conductivity, 160.0-496.0 μS/cm. Based on the levels of measurements such as the BOD concentration and DO levels, the river water is unfit for drinking, watering animals and irrigation of crops eaten raw. The results indicate that the water of a greater stretch of Thome River is polluted with domestic wastewater, agricultural and/ or surface run off.
Terrestrial and marine environments are experiencing pronounced changes. As species and their ecosystems undergo rising temperatures, varying precipitation patterns and alterations in their chemistry and phenology, there is a great deal of added stress on many organisms. Many species attempting to adapt to a rapidly changing climate are forced to migrate or to become extinct. Forest communities are changing in composition as well as migrating northward. Often, roads, cities, and other forms of development physically impede migration. Some species are not able to migrate at the pace with which their ecosystems are warming. In some forest communities, southern boundaries are migrating northward faster than northern boundaries are migrating northward which decreases the overall size of the forest and the amount of habitat available for the species therein. Some insects, like the pine beetle, thrive in warmer conditions providing significant challenges for their hosts. The oceans are warming, global circulation patterns are weakening, overturning is thwarted as there is greater stratification, and there is increased acidification. Coral reefs and other ecosystems which provide food and shelter for a whole host of other species are bleaching worldwide. The amount of carbon humans add to the atmosphere each year globally continues to climb. Currently, we add approximately 35 gigatons of carbon dioxide (CO2) equivalent to the atmosphere annually, and we have moved from approximately 280 parts per million (ppm) of CO2 prior to the Industrial Revolution to 398 ppm in 2014, which was the hottest year on record. The best atmospheric scientists agree that we should keep temperatures below the tipping point of 2° Celsius (C) in order to avert an ecosystems disaster. The purpose of this paper is to present some of the negative scenarios that have been proposed since researchers first realized that warming was inevitable by comparing early forecasts with the latest impacts.
Present research was undertaken to examine the influence of parent materials and land use on exchangeable cations in Edo state, Nigeria. This investigation was carried out with the following objectives (i) to examine the status of exchangeable cations in the soils (ii) to determine the difference in the exchangeable cations of soils amongst the different land use types in Okodobo Village. Eighteen soil samples (0-15 cm and 15-30 cm depths) were collected from three study sites viz., Secondary forest (control site) and Plantain and Oil palm (treatment sites) plantations. Exchangeable cations were analyzed using standardized methods and analyzed employing soil quality index and student t -test. The analytical results confirmed that the status of Ca++, Mg++ and Na+ were deficient, K+ was however not lacking. Student t-test revealed that there was significant difference of exchangeable cations between secondary forest and plantain land uses. Similarly, significant difference existed between plantain and oil palm land uses. Further, t-test revealed that there was no significant difference of exchangeable cations between secondary forest and oil palm land uses. Exchangeable cations decreased from surface to subsurface soils in secondary forest and oil palm land uses but increased down the soil profile in plantain land use. This research reveals the intense impact of parent materials and land use on exchangeable cations in the study area. Keeping in view the high acidic levels and low status of Ca++, Mg++ and Na+ in the soils, organic matter and agricultural lime applications are recommended respectively.
River runoff in semi-arid urban watersheds may consist entirely of treated wastewater effluent (dry-weather) and/or urban nonpoint source runoff (wet-weather), which can be a source of nutrients, bacteria, and metals to receiving waters. The purpose of this study is to identify sources of potential pollutants and to characterize urban water quality along the Los Angeles (LA) River from its head to the mouth during dry and wet weather seasons. The LA River is an effluent-dominated water body during the dry season. The three wastewater treatment plants (WWTP) including the Tillman, Burbank, and Glendale waste water treatment plants discharge the majority of the volume flowing in the LA River during the dry and wet period. The WWTPs discharge chemicals such as chloride, nitrate, and sulfate to the river. The metals are more likely attributed to street runoff. In both cases, the contamination is dispersed through various water channels that carry semi treated effluent from various sources ending up into the ocean. To understand seasonal and spatial pattern of these contaminants, the water samples for chemical and physical analysis were collected along the LA River to assess the recent pollutant deposition processes in response to extensive human activity in wet and dry seasons. The general trend of the results shows that the concentrations of anions are higher during the dry season in compare to the wet season. Anion concentration values (ppm) in the dry season ranging from 5.5-16,027 (chloride), 0-1.0 (fluoride), 0-21(nitrate), 0-1.6 (phosphate), and 13.3-2,312 (sulfate); whereas the values (ppm) for anions in the wet season ranging from 3.4-5,860 (chloride), 0-0.66 (fluoride), 0-17 (nitrate), 0-0.67 (phosphate), 7.9- 745 (sulfate). Dry season concentrations values for trace metals were obtained with values (ppb) ranging from 0.9-10 (nickel), 0.8-62 (zinc), 1-4 (arsenic), 0-1 (lead) and 0-3 (selenium). As for the wet data for trace metals (ppb) ranging 0.001-0.008 (nickel), 0.000001-0.038 (zinc), 0.0016-0.016 (arsenic), 0.00099-0.0058 (lead), 0.000001-0.0093 (selenium). Data were used to calculate mean concentrations and loads for various sources. The most likely sources for chloride are the three WWTPs in the Sepulveda Basin, Burbank, and Glendale. Other source for higher chloride level may be the tidal effect in the region closer to the ocean. The source of nitrate loading is attributed to storm drains including lawn fertilizers, septic systems, WWTPs, and agricultural runoffs in headwater area. Comparison of wet vs. dry weather loading indicates that dry weather loading can be a significant source of metals. This study indicates that constituent loading during the dry weather period can comprise a substantial portion of the total annual load in LA River urban watersheds, such as those investigated in this study. Moreover, the risks posed by the metals were highest in the dry season due to dry season runoffs. In water-limited areas such as the Los Angeles basin, urban runoff is a water resource that could improve restricted water supplies and to enhance localized renewable groundwater resources. Thus, an assessment of this precious water resource is important for local cities and regulatory organizations.
The study areas is located in the Northern, central and the southern part of Lagos Lagoon, South western Nigeria, longitude 3° 22' 27.97" to 3° 28' 58.60" East and latitude 6° 27' 41.44" to 6° 35' 42.60" North. Sediment samples were collected from bottom sediments in twelve sampling stations, with the aid of van-veen grab during the wet-season period, from May to July 2014, on a monthly basis. Sediment samples were air dried and disaggregated, 70 grams each of sediment samples were oven dried for 8 hours, and its grain size fractions determined. The result of the grain size analysis range from; coarse to very fine sand, moderate to well sorted, finely skewed to mesokurtic, while the visually described major clay fractions range from; sandy, plastic, whitish brown clay to brownish, shaly, plastic clay with occasional silt. The bi-modal peaks on the particle size plots suggest multiple source of sediment contaminants in; Unilag waterfront, Ijora and Ibeshe, and a unimodal peaks; single source of contaminant to the sediments of; Atlascove, Apapa and Ikorodu. The sieved sediments were further leached with Nitric/Hydrochloric acid (1:3), aqua regia, using APHA method and its trace metal contents analysed with Argillent 200 A model, Atomic Absorption Spectrophotometer (AAS). The analysed concentrations in mg/kg showed; Ni(Nd-17.55), Mn, (12.50-1180.25), Pb(Nd-15.37), Zn(51.68-659.55), Cu(Nd-35.55) and Cr(Nd-53.00). The major element (Fe) used as the normalizer showed a concentration of 832.64-25206.00 mg/kg. Potential contamination benchmarks; contamination factor (CF), enrichment factor (EF), geoaccumulation factor (Lgeo) and pollution load index (PLI), were used to assess whether, the observed concentrations represent background or contaminated levels. The result affirmed the elevation of Zn, Pb and Mn and moderate contamination of zinc metals at; Iddo, Okobaba, Majidun and Ijora stations and the crustal influence in the deposition of; Cu, Cr and Ni. Multivariate statistical analysis employed also affirmed these potential contamination benchmarks. Based on the results it can be concluded that zinc metal represented a contaminated level, but, the overall toxicity level of the Lagos Lagoon sediments to the aquatic ecosystem is low.