Assessment of source apportionment and composition of trace elements in rainwater in the south-eastern region of Bangladesh

<p>Rainwater is considered as a dependable potable and non-potable water source, used for domestic purposes as well as for human consumption in many cases. While it is usually believed that rainwater is safe for drinking purposes, many studies have explored the existence of trace metals in harvested rainwater, which can impose a serious health risk to human beings when present in relatively high concentrations. The concentration of trace elements in atmospheric precipitation including rainwater also provides a good indication of the environmental pollution caused by anthropogenic activities.</p><p>Chattogram, located in the south-eastern side of Bangladesh, is the busiest port city and the second-largest city in the country with a population of around 4.5 million people. With the presence of high salinity and arsenic in groundwater and poor quality of surface water in the region, rainwater harvesting is the most sustainable solution to be considered in the water system management for the area, particularly given annual mean precipitation of 2488 mm during the rainy season. In recent years, extensive studies have been carried out on the potential application of different rainwater harvesting systems across the region, but there have been very few studies devoted to the identification of the composition of trace elements in rainwater considering site-specific influences in the trace metal distribution in the rainwater.</p><p>The purpose of this study was to investigate the composition and source appointment of trace metals (Fe, Cu, Zn, Pb, Mn, Cr, and Cd) in rainwater in the south-eastern region of Bangladesh. To determine their sources and relative contributions in rainwater, a total of ninety-five rainwater samples were collected in this study from five different locations representing different land-use patterns (industrial, commercial, urban, and sub-urban) within the study area, from June 2018 to October 2019. The collected water samples were analyzed for Fe, Cu, Zn, Pb, Mn, Cr, and Cd using Atomic Absorption Spectrophotometer maintaining standard protocols. The measured trace elements from the collected rainwater samples were then compared with the WHO and Bangladesh drinking water standards.</p><p>The resulting concentration of trace metals in this study was found within the allowable limits in accordance with WHO and Bangladesh drinking water standards, confirming the suitability of rainwater as a potable water source for human consumption. The average concentration of trace metals in rainwater was found in the order of Zn ˃ Cu ˃ Fe ˃ Cr ˃ Mn ˃ Pb ˃ Cd for the tested samples. Overall, the trace metal concentrations of Cu and Zn were predominantly observed in rainwater samples collected from the industrial area, indicating the influence of anthropogenic activities on atmospheric pollution. The concentrations of the trace elements in this work were found to be overall higher when compared to those reported in other investigations around the world. The measurements of this study would provide an indication of atmospheric pollution in rainwater caused by the anthropogenic origins of trace metals as well as provide a database of trace metals in rainwater for further relevant research studies across the country.</p>

Atmospheric Pollution Monitoring by Water Rain Analysis

Environmental legislation is moving towards global standards for ease of application and to impose sanctions and penalties when necessary, without compromising human health and biota. International environmental measures for control and monitoring of atmospheric air only monitor emissions of SOx, NOx, O3, and Pb. In general, most research work in air pollution done using the analysis of elements in rainwater show analysis of trace metals such as Na, Mg, Zn, and Mn. In this work, trace metals in the rainwater at the city of Goiânia, capital of the State of Goiás, were analyzed. Goiânia is a large city set in a predominantly agricultural province located in central Brazil. Presence of trace metals in rainwater was detected, indicating atmospheric air pollution levels higher than occupational limits set by WHO.

Solubility of iron and other trace elements in rainwater collected on the Kerguelen Islands (South Indian Ocean)

The soluble fraction of aerosols that is deposited on the open ocean is vital for phytoplankton growth. It is believed that a large proportion of this dissolved fraction is bioavailable for marine biota and thus plays an important role in primary production, especially in HNLC oceanic areas where this production is limited by micronutrient supply. There is still much uncertainty surrounding the solubility of atmospheric particles in global biogeochemical cycles and it is not well understood. In this study, we present the solubilities of seven elements (Al, Ce, Fe, La, Mn, Nd, Ti) in rainwater on the Kerguelen Islands, in the middle of the Southern Indian Ocean. The solubilities of elements exhibit high values, generally greater than 70%, and Ti remains the least soluble element. Because the Southern Indian Ocean is remote from its dust sources, only a fraction of smaller aerosols reaches the Kerguelen Islands after undergoing several cloud and chemical processes during their transport, resulting in a drastic increase in solubility. Finally, we deduced an average soluble iron deposition flux of 27 ± 6 μg m−2 d−1 (~0.5 μmol m−2 d−1) for the studied oceanic area, taking into account a median iron solubility of 82% ± 18%.

Ion input via rainwater in the southwestern region of Rio Grande do Sul, Brazil

Ion input via rainfall alone and after interception by the forest canopy, constitutes an important path of biochemical cycling, although few studies have provided information on the subject so far. The objective of this work is to quantify ion inputs, via rainfall, in the southwestern region of Rio Grande do Sul state, Brazil. Ten rain gauges were mounted in a field area. The quantification of stored water volume, along with sample collection for determination of nitrate, nitrite, ammonium, phosphorus, sulfur, chlorine, calcium, magnesium, potassium and sodium contents, was done fortnightly from September 2006 to August 2008. Local annual average precipitation in the relevant period was 1,588.3 mm. The concentration of chemical elements in rainwater was found to vary throughout, being inversely correlated with the increase in rainfall, while potassium, ammonium, phosphate, sulfate, chloride and sodium were found to have a significant mutual correlation (p <0.01). Based on the annual amount of nutrient input via rainwater, it can be inferred that rainfall is an important source of chemical element input into the forest system.