Pollution and risk assessment of phenolic compounds in drinking water sources from South-Western Nigeria

Abstract

This study reports the occurrence and risk assessment of 2,4-Dinitrophenol (2,4-DNP), Phenol (PHE), and 2,4,4, in drinking water sources in three South western States in Nigeria (Osun, Oyo and Lagos). Groundwater (GW) and surface water (SW) were collected during dry and wet seasons of a year. The detection frequency of the phenolic compounds followed the trend: Phenol > 2,4-DNP > 2,4,6-TCP. The mean concentrations of 2,4-DNP, Phenol, and 2,4,6-TCP in GW/SW samples from Osun State were 639/553 µg L − 1 , 261/262 µg L − 1 , and 169/131 µg L − 1 respectively, during the rainy season and 154/7 µg L − 1 , 78/37 µg L − 1 , and 123/15 µg L − 1 during the dry season. In Oyo state, the mean concentration were 165/391 µgL − 1 for 2,4-DNP and 71/231 µgL − 1 for Phenol in GW/SW samples respectively, during rainy season. Generally, in the dry season, these values decreased. In any case, these concentrations are higher than those previously reported in water from other countries. The concentration of 2,4-DNP in water posed serious ecological risks to Daphnia on the acute scale while it was Algae on the chronic scale. Estimated daily intake and hazard quotient calculations suggests that 2,4-DNP in water pose serious toxicity concern to humans. Additionally, the concentration of 2,4,6-TCP in water from Osun State in both seasons pose signi cant carcinogenic risk to persons ingesting water from this State. Every exposure group were at risk from ingesting these phenolic compounds in water. However, this decreased with increasing age of the exposure group. Results from the Principal Component Analysis indicate that 2,4-DNP in water samples is from an anthropogenic source different from that for Phenol and 2,4,6-TCP. There is a need to treat these GW and SW before drinking while maintaining regular assessment of these water sources.drinking water (Sonawane and Korake, 2016). In Brazil, the Brazilian potability standard for drinking water set the maximum permissible level for 2,4,6-TCP at 200 ng L − 1 (Sartori et al., 2012). However, there is a dearth of data on the presence of these phenolic compounds in water bodies and drinking water sources in Africa, even though these compounds are vastly used in industries and particularly for agricultural purposes in the continent. Consequently, no limit has been determined for these priority pollutants in aquatic environments in West African countries.To make matters worse for millions of Africans, the major sources of drinking water are some of these aquatic environments, including streams, rivers, hand-dug wells and boreholes. In fact it is estimated that > 50% of Africans use groundwater as their primary source of drinking water (https://businessday.ng/opinion/article/world-water-day-2022-where-are-we/ ). Water from these sources is not pre-treated before use. The quality of these drinking water sources from Africa and especially Nigeria, with respect to phenolic compounds is relatively unknown.Based on the observed gaps, this study aims to provide baseline data on the occurrence of some p...

Electro Fenton's reaction coupled Zn-air battery for in situ pollutant degradation

“…It may be questioned that the discharge products like formate and acetate accumulate in the electrolyte, however they are value added products because of their immense techno commercial implications in industries involving food, cosmetics, cleaning supplies, and textiles. 23,24…”

“…It may be questioned that the discharge products like formate and acetate accumulate in the electrolyte, however they are value added products because of their immense techno commercial implications in industries involving food, cosmetics, cleaning supplies, and textiles. 23,24 The pollutant degradation in the cathodic compartment is the effect of a sequence of reactions involving electrochemical as well as chemical reactions. It is important to investigate the efficiency of hydroxyl radical utilization in this system.…”

“…19,22 Therefore, the development of efficient water treatment processes to remove these aromatic compounds at the source water itself is the need of the hour. 23 Here, we show that in situ peroxide production during the battery discharge can be directly utilized for pollutant degradation at the cathode of a Zn-air battery by triggering peroxideassisted Fenton's reaction. The proposed battery consists of metallic zinc (Zn) as an anode coupled with an air-based positive electrode catalyzed by anthraquinone.…”

“…19,22 Therefore, the development of efficient water treatment processes to remove these aromatic compounds at the source water itself is the need of the hour. 23…”

Distribution, Correlations, and Risk Evaluation of Endocrine Disrupting Chemicals from Indoor Aerosols within Universities in Nigeria

“…The hazard quotient (HQ) and hazard index (HI) were used to calculate the noncarcinogenic risk of indoor dust exposure as shown in eqs and : HQ = ADD RfD HI = prefix∑ HQ i where RfD is the oral reference dose value (ng/kg/day), which is 10000000 ng/kg/day each for MeP and EtP, 100000 ng/kg/day each for PrP and BuP, 4000 ng/kg/d for BPA, and 1200000 ng/kg/day for TCS . The HQ of the noncarcinogenic risk is categorized as HQ > 1, indicating a high noncarcinogenic risk, while HQ < 1 indicates a low noncarcinogenic risk …”