Assessment of Environmental Noise Pollution in Warri and Effurun Metropolitan Cities

Environmental noise pollution affects not only the quality of life, but it poses a serious health and social problem. The Cirrus integrating averaging sound level instrument: model CR262A was employed to determine the noise levels at the twenty-two (22) selected sampling stations. The measurement of the noise was carried out during the morning, afternoon, and evening periods, to evaluate noise pollution within the twin city. Results indicated that there is no much difference (p>0.05) in the mean noise values within the different periods of the day at each sampling station, but there is significant variation (p<0.05) in the mean noise values at each period of the day over all the sampling stations. The results of the noise measurement showed that Enerhen Junction and NNPC Complex recorded the highest and lowest overall noise values of 84.84+5.39 dB(A) and 70 .90+2.98 dB(A) respectively. The results of this survey showed that the noise values at all the measurements points within Warri and Effurun metropolitan cities and at all the periods of the day is more than the Nigeria Federal Ministry of Environment (NFMEnv) and World Health Organization (WHO) permissible limit of 55dB daily noise level criteria for residential areas. The ssurvey requires the need to enact and enforce permissible noise levels/standards for residential neighbourhoods of 55dB by relevant environmental authorities both at Federal and state levels instead of applying 90dB standard meant for regulations in industrial settings. Current World Environment Journal Website: www.cwejournal.org ISSN: 0973-4929, Vol. 13, No. (3) 2018, Pg. 433-444


Introduction
Noise pollution, majorly a by-product of high human population density and developed industrial state, is now globally recognized as a major challenge for the quality of life in urban areas.It is becoming progressively perpetual, yet unnoticed form of air pollution even in developed nations.BIRMA et.al., Curr.World Environ., Vol.13(3), 433-444 (2018)   adverse health effects.It also adversely affects future generations and has sociocultural, aesthetic, and economic effects. 1,2The most important factors raising noise pollution in urban areas include interalia appliances, vehicular traffic, neighborhood electrical appliances, TV and music systems.Others include public address systems, railway and air traffic, garbage trucks, construction equipment, manufacturing processes, and lawnmowers and generating sets.The noise created does not affect only people, but even oneself, fall prey to the cumulative noise generated by the household equipments used daily. 3Agarwal and Swami, confirmed that the transportation sector was one of the major contributors to noise in urban areas.Hence, as a first step towards assessment of noise pollution, measurement was taken up with emphasis on traffic noise. 4e hike in the population and in the number of vehicles movement has led to an increase in noise pollution, but noise pollution has been considered to be no effect than other contaminants in the environment. 5In comparison to many other environmental issues, noise pollution continues to increase and is accompanied by an growing number of complaints from people vulnerable to the noise.
The health significance of noise pollution are: noise-induced hearing impairment; interference with speech communication; disturbance of rest and sleep; psycho-physiological as well as mentalhealth.Other effects are decrease of children's ability to comprehend, concentration, assimilation and performance effects; effects on residential behavior and annoyance as well as interference with proposed activities. 6,7e air medium through which noise is released and moves is common to all human.Therefore People, businesses, and organizations, do not have unrestricted rights to emits noise at will, as if the resultant effects of noise were uncommon only to their private property.On the contrary, people should have obligation to use the host medium in ways that are compatible with or do not hamper other uses 8 According to Maduemezia 9 , noise pollution is one aspect of environmental pollution that is taken rather lightly in Nigeria.He asserted that greater part of the sources of noise in the society is of a social origin.However, noise, as a polluting agent in the environment, has been recognized in recent years as a serious threat to the quality of life enjoyed by people in most industrialized nations.In developing nations, however, noise pollution has not been seen as dangerous and having adverse effect on the life of the people.10,11 World Health Organisation also state that there is evidence, that disturbed sleep causes fatigue, accidents and reduced performance (Naish  et al., 2012).
The effects of noise are seldom catastrophic,and are often only transitory, but adverse effects can be cumulative with prolonged or repeated exposure.Sleep disruption, the masking of speech and television, and the inability to enjoy one's property or leisure time, impair the quality of life.This is probably the reason why not much research into environmental noise pollution has been carried out within Nigeria cities.Consequently, the need for monitoring environmental noise pollution has become necessary in Warri-Effurun and environs, so that the citizens can have a better understanding of the level of noise they are daily exposed to and the health implication.

Description of the Study Area
The study was carried out in the twin city of Effurun-Warri metropolis in Delta State of the Niger Delta Region, Nigeria and is situated on lat.5 0 52'0''E and Long. 5 0 35'0''N-(Figure 1).
The metropolis is a multicultural landscape (consisting of Urhobo, Itsekiris and Ijaws among others) with a population of 500,698. 12The coastal city is a tourist centre with a wide range of existing potential attraction Sites and Monuments, Hospitality Centres, Festivals and Dances, in addition to its known religious tolerance. 13The study area is among the largest oil-producing sites in the African continent and has a sea port strategically located in the city, making it an industrialized and highly commercial city characterized with high traffic volume all year round with frequent traffic jams at market and road junction vicinities located along the major roads in the city. 14enty-two noise monitoring stations were carefully selected to represent all the quarters of the study area with high noise pollution sources.The monitoring sites consist of road junctions and markets situated along the major roads and are opened on a daily basis from morning to evening.The monitoring stations were geo-referenced using

Fig. 1: A Map of Nigeria and map of Effurun-Warri showing the Sampling stations
Global Positioning System (GPS). 15,16Table 1 shows the monitoring stations and their respective coordinates.

Cirrus Integrating Averaging Sound Level Meter: Model CR262A Cirrus Sound Level Meter
Model CR262A is a type II, portable direct noise measuring device according to IEC 60651 specifications.It is an integrating averaging sound level hand-held meter with 35-130 dB(A) as a measuring range.The instrument is fitted with microphone interface that responds to sound pressure from the acoustic source and transforms it into an electric signal which can be interpreted by the measuring instrument.
The sound meter was calibrated by a calibrator as defined by IEC 60942 for checking the accuracy of the hand-held indicating instruments.The Calibrator is a small, battery driven device and has a standard sound level of 94 dB with an accuracy of ±0.5 dB. 17

Noise Measurement Procedure
The measurements were made at street level (at market centres' road junctions and passenger loading parks).It was a typical walk-through surveys with the Sound Level Meter (SLM) held comfortably well away from the body at a distance of about 2.0 m above the ground level with the microphone pointed horizontally to the surrounding noise sources. 18weighted instantaneous sound pressure level (LAi) measurements were taken for a period of 10 minutes per station per day for one week, (bringing the total period of reading to 70 minutes per sampling station).This procedure was carried out for morning (6:00-8:30 a.m.), afternoon (12:00-2:30 p.m.) and evening (5:00-7:30 p.m.) measurements.19 Analysis of Variance (ANOVA) was used as a statistical tool to analyse the data obtained from the noise measurement at 95% confidence level.

Result and Discussion
The results of the noise level measured in decibel {dB(A)} at 22 strategic locations at different periods of the day (morning, afternoon and evening) in Effurun and Warri metropolitan cities, Delta State, Nigeria, shows that even the lowest noise level value recorded at NNPC Complex Road (72.12 dB(A)) is more than the WHO limit of 55 dB(A) for residential environment and the mean noise level value for the control station (Oha Community) of 54.66 dB(A). 20

Morning Period
The result of the noise level for the morning period in Warri-Effurun metropolis (Table 2 and Figure 2) below shows that, Delta Steel Company (DSC) roundabout had an average noise level of 75.04±6.59dB(A).The summary of noise level measurements for the morning period, shows that Hausa Quarters

Afternoon Period
The result of the noise measurement during the afternoon period (Table 3

Evening Period
The result of the environmental noiseassessment within the study area during the evening period (Table 4 and Figure 4) showed that DSC roundabout had an average noise level of 76.80±7.37 dB(A), while 78.97±5.92dB(A) was recorded for PTI junction station.The Enerhen junction and Hausa Quarters sampling stations recorded the highest and second to the highest mean noise level during the evening measurement with values of 84.84±5.39dB (A) and 83.90 ±5.36 dB (A) respectively.The least and second lowest average noise level were

Diurnal Comparison at Each Station
When the average noise levels per station are examined across different periods of the day, one could say that the values are not the same.However, the statistical analysis (ANOVA) of the result (Table 5, and Figure 5) affirms that there is no much differences (p>0.05) between the average noise levels at varied periods (morning, afternoon and evening periods) of the day,when all the stations are considered individually.

Diurnal Comparison at all the Stations
The result of the statistical test using ANOVA also indicated that there is a significant difference at (p<0.05) of average noise level for different stations at a particular period of time.

Morning Period
The post hoc statistical analysis using Duncan multiple range shows that the morning period has four (4)

Fig. 2 :
Fig. 2:The average noise level values for the morning period of the 22 sampling stations

Fig. 3 :
Fig. 3:The average noise level values for the afternoon period of the 22 sampling stations of noise level [83.70±4.89dB(A)], while NNPC Complex Junction had the lowest value of noise level [70.90±2.98 dB(A)] during the period under review

Fig. 4 :
Fig. 4: The average noise level values for the evening period of the 22 sampling stations recorded at Demonstration Link Road and NNPC Complex Junction with values of 72.74±3.97dB(A) and 72.77±4.29 dB(A) accordingly.

Table 1 : Sampling stations and their coordinates and descriptions S/ Name of Station Elevation Coordinate Description of the measurement station N
o 31'03.7"Most busy market in the study area along warri-Sapele road.It E 05 o 45'46.2" is an activity area with high daily traffic jam.o 44'39.3"sometimes especially at resumption an closure of NNPC workers BIRMA et.al., Curr.World Environ., Vol.13(3), 433-444 (2018)

Table 3 :The values for average, minimum and maximum noise level in dB(A) during Afternoon period Afternoon S/N Sampling Sites Average Min. Max. Noise level, dB(A)
and Figure3) shows that the mean noise level values of 75.01±4.90dB(A),79.76±4.36dB(A)and 73.03±4.49dB(A)were recorded for Okere roundabout, Estate roundabout and Okumagba Avenue junction respectively.On the overall, the afternoon measurement shows that Enerhen Junction recorded the highest value BIRMA et.al., Curr.World Environ., Vol.13(3),433-444 (2018)

Table 4 : The average, minimum and maximum noise values in dB(A) during the evening period
different groups of stations that have no considerable difference (p>0.05) in their average noise values.The Group I, II, III and IV have an average noise level values ranges of 72.16dB(A) to 78.94dB(A), 74.29dB(A) to 80.86dB(A), 75.99dB(A) to 82.14 dB(A) and 78.94dB(A) to 84.60 dB(A) respectively.The groups also have 19, 17, 12 and 4 numbers of stations respectively.