Open Access Original Research Article

Contamination and Potential Ecology Risk of Heavy Metals in the Sediment of the Cau river, Vietnam

Dieu-Anh Van, Trung Hai Huynh

Asian Journal of Environment & Ecology, Page 1-10
DOI: 10.9734/ajee/2022/v18i230307

Five sediment cores collected at the Cau river section flowing through Thai Nguyen were analyzed to evaluate the vertical profile, enrichments, and contamination of six heavy metals including Cu, Pb, Zn, Cr, As, and Cd. The impacts of investigated metals on ecology were estimated by the toxic unit and the potential ecological risk index. The obtained mean heavy metal concentration in the five sediment cores for investigated metals was: Cd (0.56 - 1.74 mg kg−1) < As (10.2 - 32.3 mg kg−1) < Cr (12.1 - 36.2 mg kg−1) < Cu (16.0 - 51.2 mg kg−1) < Pb (24.5 - 85.5 mg kg−1) < Zn (48.2 - 151 mg kg−1). The spatial distribution and vertical patterns of heavy metal concentration in the sediment cores differed substantially among the investigated sites. Among the six investigated heavy metals, Cr was of natural origin while the remaining 5 metals (Cu, Pb, Zn, As, Cd) came primarily from human activities. Based on the classification using EF, Igeo, and PLI, sediment at S3, where there was a concentration of discharge from main activities of the area, was strongly contaminated with heavy metals. The other sites (S1, S2, S4, and S5) were in the condition slightly contaminated with heavy metals. As and Cd were mostly associated to the overall pollution load index of heavy metals in the sediment of the Cau river. The highest STU and considerable risk from heavy metals were observed at S3. Sediment at S1, S2, S4, and S5 posed a moderate ecological risk.

Open Access Original Research Article

Development of Height Equations for Teak (Tectona grandis L.f.) Plantation in Ketou Commune, Ketou, Republic of Benin

D. I. Adekanmbi, M. G. Saka

Asian Journal of Environment & Ecology, Page 11-21
DOI: 10.9734/ajee/2022/v18i230309

Aim: To develop Height equation for a seven years old Teak (Tectona grandis) plantation in Ketou commune, Republic of Benin.

Study Design: Simple random sampling technique was adopted for this study, in which, 25 plots of 20 x 20 m in size. Information was collected on the species tree height (TH) and Diameter at breast height (Dbh) at 1.3 m above the ground level on a randomly laid 25 plots of 20 x 20 m in size in the entire plantation.

Place and Duration: The study was carried out in a private Teak plantation in Ketou commune, Republic of Benin from October to December. 2021.

Methodology: The collected data was splitted into two parts: 1,552 trees were used for model development while the remaining 754 was used for data validation. Linear, semi-log, double and exponential equations were fitted to the calibrated tree height data, using stepwise regression method procedures in Statistical Package for Social Scientist (SPSS, version 20).

Results: The result revealed that, TH, Dbh and basal area (BA) of ranges between 2.4 – 16.3 m, 5.0 – 16.0 cm and 1.6 x 10-3 to 5.9 x 10-3 m2 respectively for both the calibrated and validated data set. Out of the total number of trees enumerated, only two diameter (dbh) class of 5 – 10 and 11 -15 cm was observed in the plantation. 270 trees (11.7 %) of the trees fell into lower diameter class of 5 to 10 cm, while 2,036 trees (88.3 %) fell into 11 to 15 cm class indicating that the most the tree species are still in pole stage. Correlation analysis between the dependent and independent variables were evaluated. A moderately negative correlation was exhibited with the weighted diameter at breast height. Considerable differences were found among the predictive ability of the selected models. The adjusted coefficient of determination values ranges between 55.5 and 96.7%, while the root mean square error and bias ranges between 0.026 to 1.638 and 1.2 x 10-3 to 5.6 x 10-3 respectively. Judging by the regression analysis criteria’s, Model III gave the highest R2Adj and lowest RMSE value among the competing models. The findings clearly shows that, Model III was the appropriate function to fits the data and was selected as the best equation for describing total height growth of Tectona grandis in Ketou commune, Republic of Benin.

Open Access Original Research Article

Heavy Metals and their Effects on Macroinvertebrates Present in the Ojo River, Lagos, Nigeria

G. A. Reis, A. A. Olayeri, A. O. Saba, T. E. Falebita, F. O. Alonge, T. O. Abdulkareem, T. F. Giwa, A. O. Mudashiru, U. O. Jibrin-yekini

Asian Journal of Environment & Ecology, Page 22-29
DOI: 10.9734/ajee/2022/v18i230310

Aim: To provide information regarding the presence of heavy metals in the tissues of crab (Potamon fluviatile), prawn (Macrobrachium rosenbergii), and crayfish (Metanephrops australiensis) obtained from the Ojo river of Lagos State, Nigeria.

Study Design: Commercially sold marine crustacean samples (crab, prawn, and crayfish) obtained from the Ojo river of Lagos, Nigeria, were assessed for the presence of heavy metals, and also the potential health risks for local consumers.

Place and Duration of Study: Ojo river, located close to Ojo local government secretariat, Ojo, Lagos State, Nigeria.

Methodology: Live samples of macroinvertebrates such as Metanephrops australiensis, Potamon fluviatile, and Macrobrachium rosenbergii were purchased from the fishermen at the riverside in Ojo and immediately transferred to the laboratory. The samples were oven-dried and ground into a fine powder, then subjected to sample digestion and finally atomic absorption spectrophotometer (AAS), to obtain the various heavy metal concentrations present in each sample.

Results: The result indicated variations in the metal body load among species. All the metals were below the FAO/WHO permissible limit for food consumption except for Cd in crayfish which was slightly beyond the set limit. The highest concentration examined were found in crayfish, followed by crab and prawn. Zinc and iron were of higher concentrations in the tissues of the macroinvertebrates while lead was the least concentrated metal present only in the tissues of crayfish and absent in the tissues of both crab and prawn.

Conclusion: The human health risk evaluation for the marine organisms indicated that both the crab and the prawn samples examined were safe for consumption, while crayfish may not be considered safe for consumption. Also, the potential health risk from consuming seafood exposed to these metals should not be ignored.

Open Access Original Research Article

Avoidance Response: A More Important Determinant of Population Immediate Decline in Guppy Fish (Poecilia reticulata Peters, 1859) Exposed to Pesticides

Olusola Ojo Ogunfeitimi, Hilary Chikaelo Umeokeke, Nnamdi Henry Amaeze, Evelyn Tibiebi Soriwei, Labinjo Ayomide Suuru, Friday Ojie Ehiguese

Asian Journal of Environment & Ecology, Page 30-41
DOI: 10.9734/ajee/2022/v18i230312

This study investigated the ability of Paraquat (herbicide) and Dichlorvos (insecticide) to elicit avoidance response in the population of Guppy fish, Poecilia reticulata and predict the population immediate decline (PID) of P. reticulata when exposed to both agrochemicals. A 96-h forced system (FS) bioassay was each conducted in five duplicate systems, each with a control experiment. The avoidance response was examined using a non-forced multi-compartmented static system (NFS). The guppies (n = 3 guppies per concentration of 6 compartments in quadruplet) were exposed to a gradient of Paraquat (0, 2.5, 5.0, 7.5, 10.0 and 15.0 mgL-1) and Dichlorvos (0, 1.6, 2.6, 3.0, 3.2 and 4.0 mgL-1). Their distributions were examined at 20 min intervals for a 3-h period (n=9observation periods). The results from 96-h FS were dose-dependent with the highest percentage mortality being 85.7% for Paraquat and 78.6% for Dichlorvos in their respective highest concentrations. The 3-h NFS exposure showed statistically significant concentration-dependent spatial avoidance. The P. reticulata avoided the lowest concentration of Paraquat (2.5mgL-1) and Dichlorvos (1.6 mgL-1) by 68.3% and 48.3% respectively. The avoidance increased significantly (p < 0.005) to 75%, for the highest concentrations of both test chemicals (15.0 and 4.0 mgL-1). The 3-hr AC50 value revealed that the guppies were more sensitive to Paraquat (0.37 mgL-1) than Dichlorvos (1.73 mgL-1). The PID was driven by the avoidance behavior (NFS) of the guppies rather than mortality (FS). The FS heretofore overestimate the environmental risk of contamination due to mandatory exposure of mobile organisms to contaminants. Rather than the traditional FS systems, NFS should be adopted and incorporated into typical bioassays for better predictive results.

Open Access Original Research Article

Risk Perceptions of Environmental and Health Problems Associated with Artisanal Crude Oil Refining in Bayelsa State, Nigeria

Ephraim-Emmanuel, Benson Chukwunweike, Okokon Enembe, Ordinioha Best

Asian Journal of Environment & Ecology, Page 42-50
DOI: 10.9734/ajee/2022/v18i230313

When crude oil is artisanally refined, it releases compounds that contribute to environmental pollution and health problems. The perceptions regarding these problems could be instrumental in tackling the involvement in these illicit activities. This study thus assessed the perception of the environmental and health risks associated with artisanal refining of petroleum products in communities in Bayelsa State.

The study was conducted among 615 adult residents of 3 selected communities in Bayelsa State. Multistage sampling was applied in selecting the respondents who provided responses to the administered questionnaires. Necessary ethical considerations were made during the conduct of this study.

Results from the study indicate that respondents had good perception regarding the possibility that environmental and health risks could occur as a result of crude oil artisanal refining activities (Criterion mean: 2.5 (62.5%); Grand mean [environmental risks]: 3.25 [81.15%]; Grand mean [health risks]: 3.13 [78.32%]) respectively.

The study found that the communities have good perceptions of environmental and health risks associated with the artisanal refining of crude oil in Bayelsa State. There is therefore need for sustained health education to maintain good perceptions of the health and environmental risks associated with petroleum-related artisanal refining.

Open Access Original Research Article

Women in Biodiversity Conservation: It’s Impact to Community

Myrna Nicol Ogoc, Lyndon Abalos Ogoc

Asian Journal of Environment & Ecology, Page 51-57
DOI: 10.9734/ajee/2022/v18i230323

Barangay San Isidro is an island community in the municipality of Lavezares with roughly 1000 residents. Fishing is the main source of living of the people. Few individuals resort to upland farming, while others subsist on rock scrapings from the mountain and bought from them by local construction companies in the mainland. Most of the women in the community do not have job. Healthcare services are inaccessible. Despite all odds the weather brings, the ill and the dying must cross the sea for medical assistance. Moreover, potable water is scarce with the well on top of the hill as the only water source of the community. Such conditions make Barangay San Isidro among the poorest Barangays of Northern Samar. The women supported with the knowledge in preparing the nursery for the propagation of mangrove. The mangrove seedlings produced and sold to Department of Environment and Natural Resources, DENR, and the Department of Tourism, DOT, with the coordination of Local Government Units as well as the local women folks in the plantation of the mangroves.

To address the most pressing problems faced by the community, trainings and seminars  were conducted to increase the people’s awareness and to capacitate the community in terms of organizational development and livelihood. Just like the experiences of other development practitioners, the passive and unreceptive attitudes of the people were observed. It took some time for the women to realize that helping each other would help them alleviate their condition. The academe being the prime mover and organizer of development programs for the women continued to inspire them and found new hope for and from the women. They were taught about the value of savings, self-reliance and commitment as very important factors for their success. They were motivated to carry out a microfinance project from a “piso-piso” savings for the future. Driven by their willingness to uplift their lives from poverty, the “piso” per day contribution raised to 20 pesos each week. The group also increased in number as weekly meetings were  conducted, which led to the realization of their vision, which became clearer as they got involved in the program.

This is where the Womens’ Association for Inter-Island Development or WAIID was born. Because of their strong commitment to help themselves and others, they continued their efforts through the help of different agencies both Government Organizations and Non-Government Organizations to finance their projects and activities. At present, WAIID has a total of P70,000 assets coming from their weekly contribution. The organization is able to lend 4000 to 5000 pesos to a member every week for putting up small businesses, such as sari-sari store and food vending, which support the needs of their families. On top of meeting the daily needs of their families, their aspirations levelled up as well. They aspired of sending their children to school, which has driven them to fund a scholarship program for their kids. Their livelihood came in varied means; they also sold mangrove propagules for planting projects. The men likewise, helped by means of performing heavy tasks which the women were limited at doing, such as in the crab-fattening farm. Monthly livelihood trainings and seminars were conducted by different agencies knowing the womens’ group commitment and activities reflective of good governance.

The effort did not end there. The island’s rich Lalaguna mangrove eco-park, which puts the island in the map of stunning ecotourism destinations in the province, offers a great potential for  future livelihood and ecotourism program of the community. The site will be in the roster with the majestic rock formations of Biri Island in tour packages which are in the offing. Managed by the WAIID women, a pavilion built at the site caters to tourists; with a good provision of food   and other amenities and a nice tour around the mangrove forest makes everyone feels nature at its best.

“Opportunity knocks once,” so the cliché goes and these women had a good grip of it. Having a sense of ownership of these opportunities and the desire to live better lives for their families and the community propel them to redefine life out of poverty. They turned shortcomings, both personal and government services, to become self-sufficient through the support of brave men and women who took the chance to see what was behind the thick foliage of mangroves; better lives for the once downtrodden. The Womens’ Association for Inter-Island Development (WAIID) has so much to succeed in the future; it could be a model community to look up to someday.

Open Access Original Research Article

Mangrove Habitat Assessment in Lavezares Northern Samar

Myrna Nicol Ogoc

Asian Journal of Environment & Ecology, Page 58-73
DOI: 10.9734/ajee/2022/v18i230334

Mangrove resources of the Municipality of Lavezares, Northern Samar were estimated with a total aggregate area of 1,038.4274 hectares, the 53.12% of which are distributed along the coastal margins in mainland and 46.88% along islands of the municipality.  The mangal forests comprised of 13 true mangrove species belonging to seven families, which was predominantly of Rhizophoraceae combined with significant populations of Sonneratia and Avicennia species.  The mangrove density varies at different sampled sites  ranging from the least density of 2,100 to the densest of 24,900 stems per hectare. Six of the 12 mangrove sites have predominantly matured trees, an indicator of primary growth and six were of secondary growth with an average regenerative capacity of 72.60% of its populations.

Bakauan bankau (Rhizophora stylosa) has the highest density of 840 trees per hectare with a relative density of 35 percent followed by Api-api (Avicennia officinales) with density of 507 trees per hectare with relative density of 21 percent. Other densities include Pagatpat (Sonneratia alba) with 453 trees per hectare and 19 percent relative density. Bakauan lalake (Rhizophora apiculata has the least density of 267 with relative density of 12 percent.      

For purposes of determining the number of saplings/wildlings in the study area, the mangrove assessment team established 3 regenerative plots (1m x 1m) per quadrat.

The use of acquiring data on the number of saplings in mangrove assessment is to provide information whether the area could regenerate naturally or it needs to have interventions like assisted natural regeneration or reforestation.

Based on the findings, there were only 41 saplings/seedlings encountered in all quadrats during the assessment. It implies that the area is not capable of regenerating itself naturally. Intervention like assisted natural regeneration through enrichment planting is necessary.

Assisted natural regeneration is the human protection and preservation of natural tree seedlings in forested areas like mangroves and improvement of the percentage of desirable species or genotypes and increasing biodiversity in a forest by interplanting.