Monitoring of carbaryl and cypermethrin concentrations in water and soil in Southern Malawi
- PDF / 737,331 Bytes
- 14 Pages / 547.087 x 737.008 pts Page_size
- 114 Downloads / 181 Views
Monitoring of carbaryl and cypermethrin concentrations in water and soil in Southern Malawi Charity Kanyika-Mbewe & Benard Thole & Rodgers Makwinja & Chikumbusko Chiziwa Kaonga
Received: 30 September 2019 / Accepted: 17 August 2020 # Springer Nature Switzerland AG 2020
Abstract Carbaryl (a carbamate insecticide) and cypermethrin (a synthetic pyrethroid insecticide) are extensively used in agriculture. However, the presence of these insecticides in the environment constitutes a significant source of ecological contamination. This study determined the levels of these insecticides in Lisungwi, Neno District, a cotton-growing area in Southern Malawi. A total of 81 soil samples (500 g each) were collected from six sampling points (33 in dry season and 48 rainy season). A total of 86 water samples (500 ml each) were collected seasonally (20 from shallow wells, 18 from streams, and 48 from boreholes). High-performance liquid chromatography (HPLC) was used to determine carbaryl while UV/Vis spectrophotometer detected cypermethrin. Paired t test showed a significant (p < 0.05) difference between rainy season carbaryl (in water and soil) and maximum recommended levels (MRL) (Canadian guidelines and Australian Guidelines). Similarly, a significant (p < 0.05) difference between carbaryl and WHO limits and US MRL was reported in water and soil during the rainy C. Kanyika-Mbewe : B. Thole : C. C. Kaonga (*) Physics and Biochemical Sciences Department, University of Malawi, The Polytechnic, P/Bag 303, Chichiri, Blantyre 3, Malawi e-mail: [email protected] R. Makwinja African Center of Excellence for Water Management, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia R. Makwinja Senga Bay Fisheries Research Unit, P.O.Box 316, Salima, Malawi
season. A similar observation was made for cypermethrin. Specifically, carbaryl (0.083–0.254 mg/ L in surface water and 0.165–0.492 mg/L in groundwater) and cypermethrin (8.115–15.460 mg/L in surface water and 4.48–12.18 mg/L in groundwater) concentrations during the rainy season were above the recommended limits. On the other hand, cypermethrin (0.01– 0.048 mg/L) in the soil samples during the rainy season was below the recommended limits while carbaryl (1.67–1.305 mg/L) was above the recommended limits. Higher carbaryl and cypermethrin values were recorded during the rainy season than the dry season. Nitrate, pH, and EC and the insecticides (carbaryl and cypermethrin) depicted strong correlation and significance (p < 0.05), suggesting that these factors influenced their persistence in both soil and water. The study provides evidence that Lisungwi has cypermethrin and carbaryl concentrations above the recommended limits and their presence varies with seasons—a situation considered to be a serious threat to both aquatic biota and humans. Keywords Cotton . Contamination . Concentration . Insecticides . Malawi
Introduction Pesticides (which include insecticides, herbicides, rodenticides, and nematicides, among others) are detrimental to human health and the environment (Tariq et
Data Loading...
