Readings taken in the bedrooms of Senglea residences whose owners complained of incessant humming noises from Palumbo shipyards showed that with the window open, the noise levels exceeded the World Health Organisation threshold of 30 decibels, a court heard today.
However, the shipyard owners disputed the value of the threshold limit saying that the noise levels were still within the WHO nighttime parameter which they claimed was 40 decibels.
The contrasting interpretations were given before Magistrate Aaron Bugeja who is presiding the criminal complaint filed by Senglea Residents Association against the Palumbo owners, regarding noise disturbances at night between 28 and 29 January. The complaint has also been filed against the captain and inspector of a tugboat named Hamal, which was supplying electricity to another vessel at dock number 6.
During today’s sitting court-appointed expert Prof. Joseph Agius – a former dean at the engineering department - took the witness stand to explain the results of onsite scientific inspections carried out last night in Sengela between 11.30pm and 3am.
He said that the highest level was recorded near the Gardjola watch tower but noted that there was also the noise being generated from a yacht outside the shipyard at Boiler Wharf.
The expert noted that the two main sources of noise were the diesel generators inside the tugboat and the much larger diesel generator of merchant vessel Argentina Grande which was further away from the residents in Dock 6. Prof. Agius explained that readings taken within the bedrooms of the complainants, reached up to 40.5 decibels with the window open and 30.1 decibels when the windows were closed.
He added that the humming noise about which the residents had complained was perfectly compatible with that emanated by the diesel engine inside a generator. However, he noted that the one inside the tugboat was much smaller than the one powering the Argentina Grande.
Nevertheless he pointed out that it was difficult for the human ear to determine the source of a noise if these had identical characteristics. Asked by the court to give a rough approximation of the noise level inside the court room, he said it would be about 50db.
The expert said that distance, humidity levels and reverberations were other variables which one needed to take account when assessing noise levels.
The court referred to the testimony given by Senglea resident Jesmond Bonnici who had testified that the noise was being emanated from Grande Argentina but decreased when it was shifted from dock 5 to 6, last Monday.
The expert said such explanation made sense as the source had been further away from its original position. The expert said that he could approximately determine the previous noise level, when the large vessel was closer to the residence. He later said this could increase by 4 to 5 db.
Palumbo director, Joseph Calleja who is one of the three persons against whom the charges were filed, today also took the witness stand and pointed that that the readings were taken on a night when harbour activity had increased.
He also said that at present there were some 110 ships in the harbour and so the source of inconvenience could have outside their facility, perhaps in the surrounding industrial zone.
In its submission the defence led by lawyers Matthew Brincat and Abigail Bugeja referred to various discrepancies between the residents on the source of the inconvenience.
The defence also noted how the police had failed to verify if the humming noise was audible near the residences of the complainants, when the complaints had been filed. The defence argued that it was plausible and acceptable to have some background noise in a harbor area, as long as this would not prevent residents from sleeping at night.
The case continue next Friday when Magistrate Bugeja will give his decision.