Risk Assessment of Heavy Metals Contamination in Soil and Two Rice (Oryza sativa L.) Varieties Irrigated with Paper Mill Effluent

Abstract

Heavy metal pollution from industrial wastewaters has become an issue of global concern. These wastewaters are frequently used for inland irrigation which possess a serious risk of heavy metal contamination of both soil and cultivated crops. The problem is more common in developing countries like India where industrial wastewaters are often discharged without appropriate treatments. Therefore, this study aimed at assessing the impact of paper mill effluent for irrigation on the growth, productivity, and heavy metal accumulation potential of two rice (Oryza sativa L.) varieties (PB-1121 and PR-121). Water, soil, and rice crop samples were obtained from the vicinity of Saharanpur city, Uttar Pradesh, India, and subsequently analyzed for selected physicochemical and heavy metal parameters. Results showed that paper mill effluent and nearby Kali River water had significant (p < 0.05) loads of pollutants that impacted the soil properties. Moreover, the maximum plant height (123.48 ± 4.86 and 98.83 ± 2.02 cm); total chlorophyll (6.70 ± 0.25 and 6.64 ± 0.17 mg/g); leaf carotenoids (0.67 ± 0.08 and 0.63 ± 0.05 mg/g); starch content (71.08 ± 2.05 and 72.60 ± 1.63%); amylose content (25.10 ± 1.32 and 20.28 ± 1.24%); crop yield (4270.20 ± 75.12 and 5830.58 ± 63.10 kg/ha); and straw yield (5472.05 ± 93.90 and 6683.76 ± 61.26 kg/ha) of PB-1121 and PR-121, respectively, were observed using Kali River water irrigation source as compared to paper mill effluent and borewell water. The order of heavy metal accumulation in rice straw and grain followed: Fe > Mn > Zn > Cu > Cr > Cd. Similarly, the bioaccumulation factors for heavy metals in rice straw and grain were observed as >1 and <1, respectively. Moreover, the target hazard quotient (THQ) showed that there was no potential health risk of heavy metal in rice irrigated with contaminated water supply except for the PR-121 variety irrigated with Kali River water where the health risk index (HRI) value exceeded the limit (>1). As a result, the findings of this study provide useful information about the current state of heavy metal pollution and the health risks associated with rice crops irrigated with contaminated water sources.

Impact of Irrigation with Contaminated Water on Heavy Metal Bioaccumulation in Water Chestnut (Trapa natans L.)

“…In a report, Laohaprapanon et al [30] stated that wood industry-based waters have high total organic carbon (1376 ± 62 mg/L) and COD (4380 ± 94 mg/L) levels of extreme environmental toxicity even if heavily diluted. Similarly, the study on rice fields irrigated with paper mill wastewater in the Saharanpur district revealed the serious pollution of such waters [4]. Zones 1 and 3 showed a strong positive correlation with increased TSS in pond water (Figure 2a) matching in the same PCA quadrant.…”

“…The findings showed a significant accumulation of potentially toxic elements in rice fields, with only health risks in the PR-121 rice variety, which indicates a minor accumulation in the edible part of the crop [4]. Heavy metals bioaccumulation in human-consumed crops can lead to health risks varying from diarrhea to anemia, mental and central nervous dysfunction, childbirth complications, and cancer [4]. Thus, adequate monitoring of water resources either for direct consumption or to be used for agricultural production is crucial to avoid contracting transmissible diseases such as cholera and typhoid [5,6].…”

“…Specifically, the urban areas (Zone 2) had significantly (p < 0.05) These findings may be related to the excessive use of fertilizers in agricultural lands by farmers aiming to increase crop yields, which results in water source pollution. Besides that, a recent study showed that the liberation of municipal, wood, and paper mill wastewater [4] based in the Saharanpur region in water canals increases the pollutants levels posing serious health risks. The nearby wood and paper industries in the Saharanpur region are regarded as a source of highly contaminated wastewater that has been released into the wild without any pre-treatment [28,29].…”

“…Recently, a study evaluated the soil heavy metal bioaccumulation (transfer of heavy metals into vegetative parts of cultivated rice plants) originating from Kali River irrigation water in which paper mill effluents are liberated. The findings showed a significant accumulation of potentially toxic elements in rice fields, with only health risks in the PR-121 rice variety, which indicates a minor accumulation in the edible part of the crop [4]. Heavy metals bioaccumulation in human-consumed crops can lead to health risks varying from diarrhea to anemia, mental and central nervous dysfunction, childbirth complications, and cancer [4].…”

Treated municipal wastewater as option to the use of fresh water for the cultivation of valuable pastoral species Buffel grass (Cenchrus ciliaris L.)

“…Heavy metal concentration increased in TWW treated soils. Many authors evidenced that the increased heavy metals in soils were associated with reduced microbial populations, their diversity and activity; cytotoxic effect on soils; and phytotoxicity in plants leading to reduced plant growth and chlorosis (AL-Huqail et al, 2022). The hazard of heavy metals can be contrasted by the gain of OM content in soil which consequently, allowing a major detention from soils, decreases the danger that toxic elements can reach deep layers or superficial groundwater (Khaskhoussy et al, 2022).…”