Health Risk Associated with Some Trace and Some Heavy Metals Content of Harvested Rainwater in Yatta Area, Palestine

Abstract

Rainwater is considered a dependable source for domestic purposes within rural areas in Palestine. Harvested rainwater stored in cisterns is used to leverage deficits from municipal water supplies. Harvested rainwater in areas surrounded with industrial and agricultural activities is usually contaminated with heavy and trace metals. To study the effects of human exposure to heavy and trace metals, 74 harvested rainwater samples of rain-fed cisterns were collected from different localities in the Yatta area of Palestine in the months of January and February of 2016. The water samples were analysed for Ca, Mg, Al, Fe, K, Na, Ag, Li, Co, Ba, Bi, Sr, Ga, V, Rb, Mo, Beand Tl elements utilizing ICP-MS (inductively coupled plasma mass spectrometry). The selected trace metals were found within the concentration limits of the acceptable values, in accordance with WHO and Palestinian standards, except for K and Al, which were found above the allowed limits. The potential risks of the selected trace metals on the health of the local residents, as well as the possible sources of such heavy metals, were also studied. The Chronic daily intake (CDI) of each metal and health risk indexes (HRI) were calculated for both adults and children residents. The oral ingestion pathway was studied, including exposure via drinking water. The values for CDI were found in the descending order of: Ca > Mg > Na > K > Sr > Fe > Al > Ba > Li > V > Rb > Ag > Mo > Ga > Co > Bi > TI > Be. The values of HRI were below 1 for most of the selected heavy metals, expect for Li for children, indicating potential health risk. The study also predicted that the local residents have a higher chance of developing cancer in their lifetime, especially children, with respect to the carcinogenic risk (CRing) values for Na, Mg, Al, Ba, K, Ca, Fe and Sr, which were greater than standardized limits (>10−6). The rest of the selected elements were within the acceptable limit in the five different studied locations. Furthermore, univariate, multivariate and statistical analysis depending on one-way ANOVA, inter-metal correlation, cluster analysis (CA) and principal component analysis (PCA) results revealed that geogenic and anthropogenic activities were major sources of drinking water contamination by heavy metals in the Yatta area.

The Quality of Stored Rainwater for Washing Purposes

“…The pH values of the rainwater ranged from 6.6 to 8.26 with an average value of 7.51 and was similar to that given by Al-Khatib, et al (2019) [35]. In addition, the average value of conductivity for the analyzed rainwater (47.99 µS•cm −1 ) was eight times lower than the average value (389 µS•cm −1 ) noted in rainwater from Yatta [35]. This confirms the good quality of rainwater in one of the cleaner regions of Europe.…”

“…Table 1 shows the results of physicochemical characteristic of the rainwater samples: immediately after rainfall and 10, 20, 30 days later. The pH values of the rainwater ranged from 6.6 to 8.26 with an average value of 7.51 and was similar to that given by Al-Khatib, et al (2019) [35]. In addition, the average value of conductivity for the analyzed rainwater (47.99 µS•cm −1 ) was eight times lower than the average value (389 µS•cm −1 ) noted in rainwater from Yatta [35].…”

“…Another parameter confirming this statement is the concentration of total dissolved solids (TDS). The highest value of total dissolved solids measured in the analyzed rainwater was 61 mg•dm −3 while the literature data [35] give values more than five times higher. A similar accuracy was noted for the other examined parameters such as: chlorine, ammonia, etc., which were many times lower in the examined rainwater than the literature reports [35].…”

“…The requirements for collected rainwater for washing purposes can be defined using three groups of factors: proper tank size, quality and safety of accumulated rainwater and washing quality based on outcome, results and users' satisfaction ( Figure 2). The quality and pollution of harvested rainwater depends on the environment, location, collection surface and the RWH system [31][32][33][34][35]. For the purposes of this analysis three areas of rainwater contamination have been identified (Figure 3).…”

“…In urban areas, roofs are contaminated with wind-blown dirt including heavy metals and nutrias, lichens and mosses, fungus, fecal droppings from birds and other animals, insects and litter, or fallen organic matter from the surroundings trees pollute the water [36]. Metal roofs are suitable for high quality of harvested rainwater-high temperature and ultraviolet light effectively The quality and pollution of harvested rainwater depends on the environment, location, collection surface and the RWH system [31][32][33][34][35]. For the purposes of this analysis three areas of rainwater contamination have been identified (Figure 3).…”